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Sample records for silver based wound

  1. Colloidal silver-based nanogel as nonocclusive dressing for multiple superficial pellet wounds.

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    Dharmshaktu, Ganesh Singh; Singhal, Aanshu; Pangtey, Tanuja

    2016-01-01

    A good dressing is mandatory to an uncomplicated wound healing, especially when foreign particles contaminate the wound. Various forms of dressing preparations are available for use and differ in chemical composition and efficacy. Silver has been a known agent with good antimicrobial and healing properties and recent times has seen an upsurge in various silver-based dressing supplements. We describe our report of use and efficacy of a silver nanoparticle- based gel dressing in the healing of multiple superficial firearm pellet wounds.

  2. A novel wound rinsing solution based on nano colloidal silver

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    Soheila Kordestani

    2014-10-01

    Full Text Available Objective(s: The present study aimed to investigate the antiseptic properties of a colloidal nano silver wound rinsing solution to inhibit a wide range of pathogens including bacteria, viruses and fungus present in chronic and acute wounds. Materials and Methods:The wound rinsing solution named SilvoSept® was prepared using colloidal nano silver suspension. Physicochemical properties, effectiveness against microorganism including  Staphylocoocous aureus ATCC 6538P, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 8739 ,Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, MRSA , Mycobacterium spp. , HSV-1 and H1N1, and biocompatibility tests were carried out according to relevant standards . Results: X-ray diffraction (XRD scan was performed on the sample and verify single phase of silver particles in the compound. The size of the silver particles in the solution, measured by dynamic light scattering (DLS techniqu, ranged 80-90 nm. Transmission electron microscopy (TEM revealed spherical shape with smooth surface of the silver nanoparticles. SilvoSept® reduced 5 log from the initial count of 107 CFU/mL of Staphylocoocous aureus ATCC 6538P, Pseudomonas aeruginosa ATCC 9027, Escherichia coli ATCC 8739, Candida albicans ATCC 10231, Aspergillus niger ATCC 16404, MRSA, Mycobacterium spp. Further assessments of SilvoSept solution exhibited a significant inhibition on the replication of HSV-1 and H1N1. The biocompatibility studies showed that the solution was non-allergic, non-irritant and noncytotoxic. Conclusion: Findings of the present study showed that SilvoSept® wound rinsing solution containing nano silver particles is an effective antiseptic solution against a wide spectrum of microorganism. This compound can be a suitable candidate for wound irrigation.   

  3. Colloidal silver-based nanogel as nonocclusive dressing for multiple superficial pellet wounds

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    Ganesh Singh Dharmshaktu

    2016-01-01

    Full Text Available A good dressing is mandatory to an uncomplicated wound healing, especially when foreign particles contaminate the wound. Various forms of dressing preparations are available for use and differ in chemical composition and efficacy. Silver has been a known agent with good antimicrobial and healing properties and recent times has seen an upsurge in various silver-based dressing supplements. We describe our report of use and efficacy of a silver nanoparticle- based gel dressing in the healing of multiple superficial firearm pellet wounds.

  4. Preparation and characterization of antimicrobial wound dressings based on silver, gellan, PVA and borax.

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    Cencetti, C; Bellini, D; Pavesio, A; Senigaglia, D; Passariello, C; Virga, A; Matricardi, P

    2012-10-15

    Silver-loaded dressings are designed to provide the same antimicrobial activity of topical silver, with the advantages of a sustained silver release and a reduced number of dressing changes. Moreover, such type of dressing must provide a moist environment, avoiding fiber shedding, dehydration and adherence to the wound site. Here we describe the preparation of a novel silver-loaded dressing based on a Gellan/Hyaff(®) (Ge-H) non woven, treated with a polyvinyl alcohol (PVA)/borax system capable to enhance the entrapment of silver in the dressing and to modulate its release. The new hydrophilic non woven dressings show enhanced water uptake capability and slow dehydration rates. A sustained silver release is also achieved. The antibacterial activity was confirmed on Staphylococcus aureus and Pseudomonas aeruginosa. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. The effect of a honey based gel and silver sulphadiazine on bacterial infections of in vitro burn wounds

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    Boekema, B.K.H.L.; Pool, L.; Ulrich, M.

    2013-01-01

    Bacterial contamination remains a constant threat in burn wound care. Topical treatments to combat contaminations have good bactericidal effects but can have detrimental effects for the healing process. Treatments with for example silver can increase healing times. Honey based products can be a good

  6. Topical silver for preventing wound infection

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    Storm-Versloot, Marja N.; Vos, Cornelis G.; Ubbink, Dirk T.; Vermeulen, Hester

    2010-01-01

    BACKGROUND: Silver-containing treatments are popular and used in wound treatments to combat a broad spectrum of pathogens, but evidence of their effectiveness in preventing wound infection or promoting healing is lacking. OBJECTIVES: To establish the effects of silver-containing wound dressings and

  7. In vitro cytotoxity of silver: implication for clinical wound care.

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    Poon, Vincent K M; Burd, Andrew

    2004-03-01

    In this study, we look at the cytotoxic effects of silver on keratinocytes and fibroblasts. We have assessed the viability of monolayer cultures using the MTT and BrdU assays. The composition of the culture medium and also the culture technique were modified to assess the effects of culture 'environment' on the susceptibility of the cells to the toxic action of silver. Further in vitro, experiments were performed using tissue culture models to allow cellular behavior in three dimensional planes which more closely simulated in vivo behavior. The silver source was both silver released from silver nitrate solution but also nanocrystalline silver released from a commercially available dressing. The results show that silver is highly toxic to both keratinocytes and fibroblasts in monolayer culture. When using optimized and individualized culture the fibroblasts appear to be more sensitive to silver than keratinocytes. However, when both cell types were grown in the same medium their viability was the same. Using tissue culture models again indicated an 'environmental effect' with decreased sensitivity of the cells to the cytotoxic effects of the silver. Nevertheless in these studies the toxic dose of skin cells ranging from 7 x 10(-4) to 55 x 10(-4)% was similar to that of bacteria. These results suggest that consideration of the cytotoxic effects of silver and silver-based products should be taken when deciding on dressings for specific wound care strategies. This is important when using keratinocyte culture, in situ, which is playing an increasing role in contemporary wound and burn care.

  8. An investigation of in vivo wound healing activity of biologically synthesized silver nanoparticles

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    Kaler, Abhishek; Mittal, Amit Kumar; Katariya, Mahesh; Harde, Harshad; Agrawal, Ashish Kumar; Jain, Sanyog; Banerjee, Uttam Chand

    2014-09-01

    Therapeutic use of nano-silver is claimed to have reduced side effects and enhanced curative activity as compared to its ionic counterpart (silver ions). The present work aims to screen microbes for the synthesis of silver nanoparticles (AgNPs), to formulate the nano-silver-based Carbopol gel and evaluating its wound healing efficacy on rat model. The goal was to develop the topical formulation based on bio-nano-silver to control the infection and healing the wounds with higher efficacy. Procedure involved the use of Saccharomyces boulardii for the synthesis of silver nanoparticles in the size range of 3-10 nm and these nanoparticles were used for the preparation of Carbopol-based nano-silver gel. Highly stable Carbopol nanogel was developed with good rheological properties. The burn wound healing potential of this nano-silver gel was evaluated on SD rats via visual observation, transepidermal water loss and histology of skin. Excellent wound healing was observed with AgNPs. Biologically synthesized AgNPs-based nano-silver gel showed superior wound healing efficacy as compared to marketed formulations and silver ions.

  9. Evaluation of the Xanthan-Based Film Incorporated with Silver Nanoparticles for Potential Application in the Nonhealing Infectious Wound

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    Jinjian Huang

    2017-01-01

    Full Text Available Xanthan gum is a high molecular weight polysaccharide biocompatible to biological systems, so its products promise high potential in medicine. In this study, we crosslinked xanthan gum with citric acid to develop a transparent film for protecting the wound. Silver nanoparticles (AgNPs are incorporated into the film to enhance the antimicrobial property of our biomaterial. This paper discussed the characteristics and manufacturing of this nanocomposite dressing. The safety of the dressing was studied using fibroblasts (L929 by the method of 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide (MTT assay and staining of ethidium homodimer (PI and calcein AM. The bacterial inhibition test and application of the dressing to nonhealing wounds infected with methicillin-resistant S. aureus (MRSA were performed to evaluate the antibacterial effects in vitro and in vivo, respectively. The results indicated that the dressing could restrict the formation of biofilms, reduce inflammatory reactions, and promote the angiogenesis of granulation tissues in infectious wounds. Therefore, this dressing has a great advantage over traditional clinical products especially when administered under the condition of infections or for the purpose of infection prevention.

  10. New Guar Biopolymer Silver Nanocomposites for Wound Healing Applications

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    Runa Ghosh Auddy

    2013-01-01

    Full Text Available Wound healing is an innate physiological response that helps restore cellular and anatomic continuity of a tissue. Selective biodegradable and biocompatible polymer materials have provided useful scaffolds for wound healing and assisted cellular messaging. In the present study, guar gum, a polymeric galactomannan, was intrinsically modified to a new cationic biopolymer guar gum alkylamine (GGAA for wound healing applications. Biologically synthesized silver nanoparticles (Agnp were further impregnated in GGAA for extended evaluations in punch wound models in rodents. SEM studies showed silver nanoparticles well dispersed in the new guar matrix with a particle size of ~18 nm. In wound healing experiments, faster healing and improved cosmetic appearance were observed in the new nanobiomaterial treated group compared to commercially available silver alginate cream. The total protein, DNA, and hydroxyproline contents of the wound tissues were also significantly higher in the treated group as compared with the silver alginate cream (P<0.05. Silver nanoparticles exerted positive effects because of their antimicrobial properties. The nanobiomaterial was observed to promote wound closure by inducing proliferation and migration of the keratinocytes at the wound site. The derivatized guar gum matrix additionally provided a hydrated surface necessary for cell proliferation.

  11. The Application of Bactericidal Silver Nanoparticles in Wound Treatment

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    Geewoo Nam

    2015-07-01

    Full Text Available Even with the prevalence of wounds, the medical technol‐ ogy for efficiently managing skin damage is still primitive. The disruption of any of the numerous healing processes can lead to problems in the time-sensitive healing actions of the dermal and epidermal layers. Bacterial infection is one of the major obstacles to proper wound healing as it poses a danger of causing long-term negative effects. Keeping the wound free of bacteria is imperative to the proper and hasty repair of dermal wounds. Silver has been widely used to treat wounds for its bactericidal properties. Although the mechanism of silver’s antibacterial action is not fully understood, it exhibits a significant antimicrobial efficacy against a wide spectrum of bacterial species. A number of different approaches to the mechanism are reported and presented in this review. Silver nanoparticles (AgNPs have been reported to exhibit enhanced antibac‐ terial activity due to their increased surface-area-to-volume ratio. AgNPs are capable of various modifications, signifi‐ cantly broadening the therapeutic properties of the mate‐ rial as a result. This review explores the different aspects of silver and silver nanoparticles, and their antibacterial properties, which can be applied in the field of wound treatments.

  12. Preparation and characterization of novel wound dressing based on silver nanoparticle-impregnated bacterial cellulose and bacterial cellulose-aloe vera

    International Nuclear Information System (INIS)

    Ventigan, Sarla V.; Santiago, Karen S.; Balitaan, Jolleen Natalie I.

    2015-01-01

    Ideal wound dressings stimulate wound healing, control unpleasant odors, and provide antimicrobial action in wounds. However, most traditional wound dressings such as gauze and biological dressings exhibit exudate leaking which increases the risk of infection and delayed wound healing of tissues. This study aims to develop and characterize a bio-composite of bacterial cellulose and aloe vera having the ideal features of a wound dressing from Acetobacter xylinum-activated culture medium supplemented with various aloe vera concentrations from )-50% (v/v) and the film which exhibits the most uniform results is used for the incorporation of silver nanoparticle as an antibacterial agent. The biopolymer composites of bacterial cellulose and aloe vera were developed by adding 0-50% aloe vera (v/v) in the A. xylinum-activated coconut water medium during biosynthesis in static cultivation for 10 days. The films obtained after drying the membranes were named as bacterial cellulose-aloe vera (BC-A) films. The moisture content of films reached 99% which indicates that the films may be suitable for providing a moist environment to facilitate wound healing fast. With the addition of aloe vera up to 30% (v/v) during BC synthesis, it resulted in a significant improvement in the water absorption capacity of the films showing a WAC ration of 36.46 (r.s.d.= 12.17%, n=3) compared to the unmodified film having a ratio of 9.03 (r.s.d.= 13.95%, n=3). However, the addition of aloe vera at a concentration greater than 30% (v/v) resulted in a decrease in pellicle formation which can be observed from the very weak properties of the films. The BC-A (30%) displayed significantly improved in comparison to the unmodified BC film. Also, it is capable of absorbing high amount of water than its weight and can act as a potential wound dressing which reduces irritation and inflammation. (author)

  13. Silver nanoparticles enhance wound healing in zebrafish (Danio rerio).

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    Seo, Seung Beom; Dananjaya, S H S; Nikapitiya, Chamilani; Park, Bae Keun; Gooneratne, Ravi; Kim, Tae-Yoon; Lee, Jehee; Kim, Cheol-Hee; De Zoysa, Mahanama

    2017-09-01

    Silver nanoparticles (AgNPs) were successfully synthesized by a chemical reduction method, physico-chemically characterized and their effect on wound-healing activity in zebrafish was investigated. The prepared AgNPs were circular-shaped, water soluble with average diameter and zeta potential of 72.66 nm and -0.45 mv, respectively. Following the creation of a laser skin wound on zebrafish, the effect of AgNPs on wound-healing activity was tested by two methods, direct skin application (2 μg/wound) and immersion in a solution of AgNPs and water (50 μg/L). The zebrafish were followed for 20 days post-wounding (dpw) by visual observation of wound size, calculating wound healing percentage (WHP), and histological examination. Visually, both direct skin application and immersion AgNPs treatments displayed clear and faster wound closure at 5, 10 and 20 dpw compared to the controls, which was confirmed by 5 dpw histology data. At 5 dpw, WHP was highest in the AgNPs immersion group (36.6%) > AgNPs direct application group (23.7%) > controls (18.2%), showing that WHP was most effective in fish immersed in AgNPs solution. In general, exposure to AgNPs induced gene expression of selected wound-healing-related genes, namely, transforming growth factor (TGF-β), matrix metalloproteinase (MMP) -9 and -13, pro-inflammatory cytokines (IL-1β and TNF-α) and antioxidant enzymes (superoxide dismutase and catalase), which observed differentiation at 12 and 24 h against the control; but the results were not consistently significant, and many either reached basal levels or were down regulated at 5 dpw in the wounded muscle. These results suggest that AgNPs are effective in acceleration of wound healing and altered the expression of some wound-healing-related genes. However, the detailed mechanism of enhanced wound healing remains to be investigated in fish. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Enhanced tracheostomy wound healing using maltodextrin and silver alginate compounds in pediatrics: a pilot study.

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    Hartzell, Larry D; Havens, Tara N; Odom, Brian H; Stillman, Tanya G; Boswell, Jessica L; Bower, Charles M; Richter, Gresham T

    2014-12-01

    Tracheostomy wounds are commonly encountered in children but rarely reported. Relatively few treatments are available or have been investigated to manage this problem. Healing times for pediatric tracheostomy wounds are often unpredictable and protracted. Recent use of maltodextrin gel (MD) and a silver alginate sponge (AG) at our institution has demonstrated expedited healing and interest in this novel treatment for tracheostomy wounds. We conducted an 11-month retrospective review of children with wound complications following tracheostomy placement at a tertiary care facility. Wounds were evaluated and rated based upon the National Pressure Ulcer Advisory Panel staging system. Subjects identified with stage 2 or greater tracheostomy-related ulcers treated with MD and/or AG were included. Subject characteristics and wound healing rates were tabulated in a database that included age, wound site, initial and final wound stage, type of treatment, length of treatment, and complications. Tracheostomy wounds treated as an out-patient were excluded from the study. Eighteen subjects, which included both in-patients and out-patients, were treated with AG and/or MD during the study period for tracheostomy-related wounds. Of the 26 subjects with tracheostomies performed during the study period, 10 (38.5%) were treated for postoperative wounds. A total of 11 subjects completed their in-patient wound treatment and were thus included in the study. Average subject age was 5.3 y (range 0.25-15.6 y). Wound locations were as follows: infrastomal region (n = 8), stoma (n = 2), and lateral neck (n = 1). Six subjects had stage 2 wounds, 4 had stage 3 wounds, and 1 had a stage 4 ulcer. All wounds achieved complete epithelialization following treatment with MD and/or AG. The average length of treatment was 12.8 d (range 6-28 d). No adverse effects were identified. Postoperative tracheostomy wounds are common. The use of MD and AG provides an effective and safe treatment for

  15. [Treatment of the infected wound with exposed silver-ring vascular graft and delayed Thiersch method of skin transplant covering ].

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    Nenezić, Dragoslav; Pandaitan, Simon; Ilijevski, Nenad; Matić, Predrag; Gajin, Predag; Radak, Dorde

    2005-01-01

    Although the incidence of prosthetic infection is low (1%-6%), the consequences (limb loss or death) are dramatic for a patient, with high mortality rate (25%-75%) and limb loss in 40%-75% of cases. In case of Szilagyi's grade III infection, standard procedure consists of the excision of prosthesis and wound debridement. Alternative method is medical treatment. This is a case report of a patient with prosthetic infection of Silver-ring graft, used for femoropopliteal reconstruction, in whom an extreme skin necrosis developed in early postoperative period. This complication was successfully treated medically. After repeated debridement and wound-packing, the wound was covered using Thiersch skin graft.

  16. Antibiofilm Efficacy of DispersinB Wound Spray Used in Combination with a Silver Wound Dressing

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    Purushottam V. Gawande

    2014-01-01

    Full Text Available Chronic wounds including diabetic foot ulcers, pressure ulcers, and venous leg ulcers are a worldwide health problem. As the traditional methods of treatment have proven ineffective against chronic wounds involving biofilms, there is an unmet clinical need for developing products with an antibiofilm component that inhibits and/or disrupts biofilms and thus make the biofilm-embedded bacteria more susceptible to antimicrobial therapy. We developed a DispersinB® antibiofilm enzyme-based wound spray for treating chronic wounds in conjunction with an antimicrobial. Under in vitro conditions, the DispersinB® and Acticoat™ combination performed significantly better ( P < 0.05 than Acticoat™ alone, indicating the synergy between the two compounds because of DispersinB® enhancing the antimicrobial activity of Acticoat™. Furthermore, DispersinB® wound spray enhanced the antimicrobial activity of Acticoat™ in a chronic wound mouse model of methicillin-resistant Staphylococcus aureus (MRSA infection. Thus, this novel combination of DispersinB® and Acticoat™, an antimicrobial dressing, prompts clinical evaluation for potential applications in biofilm-based chronic wound management.

  17. The combined effects of Aloe vera gel and silver nanoparticles on wound healing in rats

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    Y. Yousefpoor

    2016-01-01

    Full Text Available Objective(s: This study was aimed at investigating the synergy effects of Aloe vera gel and silver nanoparticles on the healing rate of the cutting wounds. Materials and Methods: In order to determine the concentration of silver nanoparticles in Aloe vera gel, the MBC methods were applied on the most common bacteria infecting wounds, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa. The cutting wounds with Full-thickness skin were dorsally created on rats; then the rats were divided into 4 groups. The treatments groups included: mixture of Aloe vera gel and silver nanoparticles, Aloe vera gel alone and silver nanoparticles alone in addition to control groups. The treatment was carried out for 2 weeks and the size of the wound closures were measured by an image software analysis. Results:There was no significant difference (p

  18. Isolation and identification of burn wound superbugs by molecular technique and their susceptibility to silver nanoparticles

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    Mala, R.; Celsia, A. S. Ruby

    2018-02-01

    Burn wound is a global problem affecting millions of people. It is the major cause of mortality and morbidity. This study was aimed to isolate and identify the wound isolates by 16S rRNA and to assess their susceptibility to antibiotics and silver nanoparticles. Silver nanoparticles were synthesized using aqueous extract of A.indica. The silver nanoparticles were characterized by FESEM, XRD, FTIR and DSC. Antibacterial susceptibility of the isolates was assessed by well diffusion method. The wound isolates were identified as S.aureus and E.coli. Both isolates were resistant to β lactum antibiotics, aminoglycoside, quinolones and macrolides. The inhibition zone exhibited by all antibiotics against both organisms was less than 5 mm. The size of silver nanoparticles were recorded as 55 nm. XRD confirmed the crystalline nature of the nanoparticles. TGA and DSC of silver nanoparticles showed the loss of weight and the melting point of silver nanoparticles was recorded at 871.3°C. Silver nano particles inhibited S.aureus and E.coli with an inhibition zone of 27 mm and 32 mm respectively. Therefore the study demonstrated that only silver containing dressings can be used in burn wounds infected by multi drug resistant super bugs.

  19. Fabrication of transparent quaternized PVA/silver nanocomposite hydrogel and its evaluation as an antimicrobial patch for wound care systems.

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    Bhowmick, Sirsendu; Mohanty, Sujata; Koul, Veena

    2016-11-01

    Grafting of quaternary nitrogen atoms into the backbone of polymer is an efficient way of developing new generation antimicrobial polymeric wound dressing. In this study, an elastic, non-adhesive and antimicrobial transparent hydrogel based dressing has been designed, which might be helpful for routine observation of wound area without removing the dressing material along with maintaining a sterile environment for a longer period of time. Green synthesized silver nanoparticles have been loaded into the quaternized PVA hydrogel matrix to improve its antimicrobial property. Silver nanoparticles loaded quaternized PVA hydrogel showed enhanced mechanical and swelling properties compared to native quaternized PVA hydrogel. Release kinetics evaluated by atomic absorption spectroscopy revealed that the release mechanism of silver nanoparticles from the hydrogel follows Fickian diffusion. Antimicrobial efficacy of the hydrogels was evaluated by disk diffusion test on Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. After 96 h of release in phosphate buffer, the growth inhibition zone created by silver nanoparticless loaded quaternized PVA hydrogel is comparable to that created by ampicillin. These observations assert that the silver nanoparticles loaded quaternized PVA hydrogel acts as a reservoir of silver nanoparticles, which helps in maintaining a sterile environment for longer time duration by releasing Ag nanocrystallite in sustained manner.

  20. Efficacy of silver coated surgical sutures on bacterial contamination, cellular response and wound healing

    International Nuclear Information System (INIS)

    Gallo, Anna Lucia; Paladini, Federica; Romano, Alessandro; Verri, Tiziano; Quattrini, Angelo; Sannino, Alessandro; Pollini, Mauro

    2016-01-01

    The resistance demonstrated by many microorganisms towards conventional antibiotics has stimulated the interest in alternative antimicrobial agents and in novel approaches for prevention of infections. Silver, a natural braod-spectrum antimicrobial agent known since antiquity, has been widely employed in biomedical field due to its recognized antibacterial, antifungal and antiviral properties. In this work, antibacterial silver coatings were deposited on absorbable surgical sutures through the in situ photo-chemical deposition of silver clusters. Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and thermo-gravimetric analysis (TGA) were performed in order to investigate the presence and distribution of the silver clusters on the substrate. The amounts of silver deposited and released by the silver treated sutures were calculated through Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS), and the results were related to the biodegradation of the material. The microbiological properties and the potential cytotoxicity of the silver-treated sutures were investigated in relation with hydrolysis experiments, in order to determine the effect of the degradation on antibacterial properties and biocompatibility. - Highlights: • The in situ photo-deposition of silver nano-coatings was used to develop silver treated PGLA sutures. • The silver particles deposited had good distribution and strong adhesion to the substrate. • The silver treated sutures demonstrated good biocompatibility and antibacterial capability. • The presence of silver promoted cell migration and proliferation in the wound area.

  1. Efficacy of silver coated surgical sutures on bacterial contamination, cellular response and wound healing

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    Gallo, Anna Lucia [Department of Engineering for Innovation, University of Salento, Via Monteroni, 73100 Lecce (Italy); Paladini, Federica, E-mail: federica.paladini@unisalento.it [Department of Engineering for Innovation, University of Salento, Via Monteroni, 73100 Lecce (Italy); Romano, Alessandro [Neuropathology Unit, Institute of Experimental Neurology and Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan (Italy); Verri, Tiziano [Di.S.Te.B.A., University of Salento, Via per Monteroni, 73100 Lecce (Italy); Quattrini, Angelo [Neuropathology Unit, Institute of Experimental Neurology and Division of Neuroscience, IRCCS San Raffaele Scientific Institute, via Olgettina 60, 20132 Milan (Italy); Sannino, Alessandro; Pollini, Mauro [Department of Engineering for Innovation, University of Salento, Via Monteroni, 73100 Lecce (Italy)

    2016-12-01

    The resistance demonstrated by many microorganisms towards conventional antibiotics has stimulated the interest in alternative antimicrobial agents and in novel approaches for prevention of infections. Silver, a natural braod-spectrum antimicrobial agent known since antiquity, has been widely employed in biomedical field due to its recognized antibacterial, antifungal and antiviral properties. In this work, antibacterial silver coatings were deposited on absorbable surgical sutures through the in situ photo-chemical deposition of silver clusters. Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and thermo-gravimetric analysis (TGA) were performed in order to investigate the presence and distribution of the silver clusters on the substrate. The amounts of silver deposited and released by the silver treated sutures were calculated through Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS), and the results were related to the biodegradation of the material. The microbiological properties and the potential cytotoxicity of the silver-treated sutures were investigated in relation with hydrolysis experiments, in order to determine the effect of the degradation on antibacterial properties and biocompatibility. - Highlights: • The in situ photo-deposition of silver nano-coatings was used to develop silver treated PGLA sutures. • The silver particles deposited had good distribution and strong adhesion to the substrate. • The silver treated sutures demonstrated good biocompatibility and antibacterial capability. • The presence of silver promoted cell migration and proliferation in the wound area.

  2. Symbiosis theory-directed green synthesis of silver nanoparticles and their application in infected wound healing

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    Wen L

    2016-06-01

    Full Text Available Lu Wen,1 Pei Zeng,1 Liping Zhang,1 Wenli Huang,1 Hui Wang,2 Gang Chen1 1Department of Pharmaceutics, School of Pharmacy, 2School of Traditional Chinese Medicine, Guangdong Pharmaceutical University, Guangzhou, People’s Republic of China Abstract: In this study, silver nanoparticles (AgNPs were synthesized for the first time using an antibacterial endophytic fungus of Chinese medicinal herb Orchidantha chinensis, which has anti-inflammatory and antimicrobial activities. The AgNPs were analyzed by various characterization techniques to reveal their morphology, chemical composition, and stability. Also, the relationship between Chinese medicinal herbs, endophytic fungi, and the property of AgNPs was investigated for the first time. Interestingly, an experiment performed in this study revealed the proteins produced by the endophytic fungus to be capped on the nanoparticles, which led to an increase in the stability of spherical and polydispersed AgNPs with low aggregation for over 6 months. More importantly, further study demonstrated that the AgNPs possessed superior antibacterial activity and effectively promoted wound healing. Altogether, the biosynthesis of active AgNPs using the endophytic fungus from Chinese medicinal herb based on the symbiosis theory is simple, eco-friendly, and promising. Keywords: silver nanoparticles, Orchidantha chinensis, endophytic fungi, symbiosis theory, wound healing

  3. Silver nanoparticle/bacterial cellulose gel membranes for antibacterial wound dressing: investigation in vitro and in vivo

    International Nuclear Information System (INIS)

    Wu, Jian; Zheng, Yudong; Wen, Xiaoxiao; Lin, Qinghua; Chen, Xiaohua; Wu, Zhigu

    2014-01-01

    Bacterial cellulose (BC) has attracted increasing attention as a novel wound dressing material, but its antimicrobial activity, which is one of the critical skin-barrier functions in wound healing, is not sufficient for use in practical applications. To overcome such a deficiency, silver nanoparticles were generated and self-assembled on the surface of BC nanofibers, forming a stable and evenly distributed Ag nanoparticle coated BC nanofiber (AgNP-BC). The performance of AgNP-BC was systematically studied in terms of antibacterial activities, cytocompatibility and effects on wound healing. The results showed that AgNP-BC exhibited significant antibacterial activity against Staphylococcus aureus. Moreover, AgNP-BC allowed attachment, and growth of rat fibroblasts with low cytotoxicity emerged. Based on these advantages, AgNP-BC samples were applied in a second-degree rat wound model. Wound flora showed a significant reduction during the healing. The fresh epidermal and dermis thicknesses with AgNP-BC samples were 111 and 855 µm respectively, higher than 74 and 619 µm for BC groups and 57 and 473 µm for untreated control wounds. The results demonstrated that AgNP-BC could reduce inflammation and promote scald wound healing. (paper)

  4. Wound healing applications of biogenic colloidal silver and gold nanoparticles: recent trends and future prospects.

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    Ovais, Muhammad; Ahmad, Irshad; Khalil, Ali Talha; Mukherjee, Sudip; Javed, Rabia; Ayaz, Muhammad; Raza, Abida; Shinwari, Zabta Khan

    2018-05-01

    Nanotechnology has emerged as a prominent scientific discipline in the technological revolution of this millennium. The scientific community has focused on the green synthesis of metal nanoparticles as compared to physical and chemical methods due to its eco-friendly nature and high efficacy. Medicinal plants have been proven as the paramount source of various phytochemicals that can be used for the biogenic synthesis of colloidal silver and gold nanoparticles as compared to other living organisms, e.g., microbes and fungi. According to various scientific reports, the biogenic nanoparticles have shown promising potential as wound healing agents. However, not a single broad review article was present that demonstrates the wound healing application of biogenic silver and gold nanoparticles. Foreseeing the overall literature published, we for the first time intended to discuss the current trends in wound healing via biogenic silver and gold nanoparticles. Furthermore, light has been shed on the mechanistic aspects of wound healing along with futuristic discussion on the faith of biogenic silver and gold nanoparticles as potential wound healing agents.

  5. Fabrication of Antibacterial Wound Dressings from Silk Fibroin and Silver Nano particles

    International Nuclear Information System (INIS)

    Uttayarat, P.; Jetawattana, S.; Suwanmala, P.; Eamsiri, J.; Pongpat, S.

    2011-06-01

    Full text: Patients with burn wounds that cover large body surface area are susceptible to infection which can lead to fatality. Wound dressings or skin grafts are needed to cover the wound during the regeneration of new skin tissue. The aim of this research is to fabricate antibacterial wound dressings from silk fibroin derived from the natural silk cocoon and silver nanoparticles (AgNPs) prepared by gamma irradiation. Fibroin mats composed of nonwoven fibers with diameter of 670± 11.5 nm were fabricated by electro spinning. Using gamma irradiation, the starting silver nitrate solution was reduced to colloidal AgNPs. The fibroin mats were coated with AgNPs at various AgNP concentration and then evaluated for their antibacterial property by disc diffusion test. The concentration of colloidal AgNP solution ≤ 1 mM was found to be as sufficient in inhibiting the growth of Pseudomonas aeruginosa and Staphylococcus aureus as commercial wound dressings embedded with silver ions. These results demonstrate that electro spun fibroin mats coated with AgNPs exhibite antibacterial property and can be further developed for the treatment of burn wounds

  6. Silver-Collagen Dressing and High-voltage, Pulsed-current Therapy for the Treatment of Chronic Full-thickness Wounds: A Case Series.

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    Zhou, Kehua; Krug, Kenneth; Stachura, John; Niewczyk, Paulette; Ross, Michael; Tutuska, Justine; Ford, Gregory

    2016-03-01

    Research suggests high-voltage, pulsed-current electric therapy (HVPC) is safe and effective for treating chronic wounds, and some data suggest silver- and collagen-based dressings may facilitate healing. A combination therapy utilizing both HVPC and silver-collagen dressing may present clinical advantages. To explore the effect of the combined therapy for chronic full-thickness wounds, a prospective, consecutive case series study was conducted. All participants were adults with wounds of at least 6 weeks' duration. After obtaining informed consent, patient and wound characteristics were obtained, wounds were assessed and measured, and patients received 2 to 3 HVPC treatments per week followed by application of the silver- and collagen-based dressing for a period of 2 weeks. Data were analyzed descriptively, and changes in wound size and volume from baseline were analyzed using Wilcoxon Signed Rank Test. The dressings were saturated with normal saline, used simultaneously during the 45-minute HVPC treatment, and left on top of the wound after treatment. The HVPC electro pads (stainless steel electrodes with a sponge interface) also were moistened with normal saline and the cathode placed on top of the wound. If the patient had more than 1 wound on the same leg, the anode was placed on the additional wound (otherwise over the intact skin nearby). Secondary dressings (eg, foam and/ or gauze) were used as clinically appropriate, and a 4-layer compression wrap was used, if indicated, for patients with venous ulcers. Ten (10) patients (3 women, 7 men, 57.30 ± 9.70 years old with 14 wounds of 273.10 ± 292.03 days' duration before study) completed the study and were included in the final analyses. Average wound surface area decreased from 13.78 ± 21.35 cm(2) to 9.07 ± 16.81 cm(2) (42.52% ± 34.16% decrease, P = 0.002) and wound volume decreased from 3.39 ± 4.31 cm(3) to 1.28 ± 2.25 cm(3) (66.84% ± 25.07% decrease, P = 0.001). One (1) patient was discharged with

  7. Qualitative bacteriology in malignant wounds- a prospective, randomized, clinical study to compare the effect of honey and silver dressings

    DEFF Research Database (Denmark)

    Lund-Nielsen, Betina; Adamsen, Lis; Gottrup, Finn

    2011-01-01

    ¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿¿ Between 5% and 10% of cancer patients develop malignant wounds. In vitro and some clinical studies suggest that silver- or honey-coated dressings may have an antibacterial effect in nonmalignant wounds, but their possible antibacterial effect in malignant wounds remains unknown. ...

  8. A pre-clinical evaluation of silver, iodine and Manuka honey based dressings in a model of traumatic extremity wounds contaminated with Staphylococcus aureus.

    Science.gov (United States)

    Guthrie, Hugo C; Martin, Kevin R; Taylor, Christopher; Spear, Abigail M; Whiting, Rachel; Macildowie, Sara; Clasper, Jonathan C; Watts, Sarah A

    2014-08-01

    Prevention of extremity war wound infection remains a clinical challenge. Staphylococcus aureus is the most common pathogen in delayed infection. We hypothesised that choice of wound dressings may affect bacterial burden over 7 days reflecting the current practice of delayed primary closure of wounds within this timeframe. A randomised controlled trial of 3 commercially available dressings (Inadine(®) (Johnson & Johnson, NJ, USA), Acticoat(®) (Smith & Nephew, Hull, UK), Activon Tulle (Advancis Medical, Nottingham, UK)) was conducted in a rabbit model of contaminated forelimb muscle injury. A positive control group treated with antibiotics was included. Groups were compared to a saline soaked gauze control. The primary outcome was a statistically significant reduction (p injury. Secondary outcome measurements included bacteraemias, observational data, whole blood determination, ELISA for plasma biomarkers, PCR array analysis of wound healing gene expression and muscle/lymph node histopathology. Antibiotic, Inadine and Acticoat groups had statistically significant lower bacterial counts (mean 7.13 [95% CI 0.00-96.31]×10(2); 1.66 [0.94-2.58]×10(5); 8.86 [0.00-53.35]×10(4)cfu/g, respectively) and Activon Tulle group had significantly higher counts (2.82 [0.98-5.61]×10(6)cfu/g) than saline soaked gauze control (7.58 [1.65-17.83]×10(5)cfu/g). There were no bacteraemias or significant differences in observational data or whole blood determination. There were no significant differences in muscle/loss or pathology and lymph node cross-sectional area or morphology. There were some significant differences between treatment groups in the plasma cytokines IL-4, TNFα and MCP-1 in comparison to the control. PCR array data demonstrated more general changes in gene expression in the muscle tissue from the Activon Tulle group than the Inadine or Acticoat dressings with a limited number of genes showing significantly altered expression compared to control. This study has

  9. Antimicrobial activity of silver nanoparticles synthesized using honey and gamma radiation against silver-resistant bacteria from wounds and burns

    Science.gov (United States)

    Hosny, A. M. S.; Kashef, M. T.; Rasmy, S. A.; Aboul-Magd, D. S.; El-Bazza, Z. E.

    2017-12-01

    Silver nanoparticles (AgNPs) are promising antimicrobial agents for treatment of wounds and burns. We synthesized AgNPs using honey at different pH values or with different gamma irradiation doses. The resulting nanoparticles were characterized by UV-vis spectroscopy, TEM, DLS and FTIR. Their antimicrobial activity, against standard bacterial strains and silver-resistant clinical isolates from infected wounds and burns, was evaluated in vitro through determination of their minimum inhibitory concentration (MIC). AgNPs prepared using 30 g of honey exposed to 5 kGy gamma radiation had the best physical characters regarding stability and uniformity of particle size and shape. They recorded the lowest MIC values against both the standard and silver-resistant isolates. In conclusion, honey and gamma radiation can be used in synthesis of highly stable pure AgNPs, without affecting the physico-chemical and antimicrobial activity of honey. This offered an advantage in terms of inhibition of silver-resistant bacteria isolates.

  10. Bioimpedance measurement based evaluation of wound healing.

    Science.gov (United States)

    Kekonen, Atte; Bergelin, Mikael; Eriksson, Jan-Erik; Vaalasti, Annikki; Ylänen, Heimo; Viik, Jari

    2017-06-22

    Our group has developed a bipolar bioimpedance measurement-based method for determining the state of wound healing. The objective of this study was to assess the capability of the method. To assess the performance of the method, we arranged a follow-up study of four acute wounds. The wounds were measured using the method and photographed throughout the healing process. Initially the bioimpedance of the wounds was significantly lower than the impedance of the undamaged skin, used as a baseline. Gradually, as healing progressed, the wound impedance increased and finally reached the impedance of the undamaged skin. The clinical appearance of the wounds examined in this study corresponded well with the parameters derived from the bioimpedance data. Hard-to-heal wounds are a significant and growing socioeconomic burden, especially in the developed countries, due to aging populations and to the increasing prevalence of various lifestyle related diseases. The assessment and the monitoring of chronic wounds are mainly based on visual inspection by medical professionals. The dressings covering the wound must be removed before assessment; this may disturb the wound healing process and significantly increases the work effort of the medical staff. There is a need for an objective and quantitative method for determining the status of a wound without removing the wound dressings. This study provided evidence of the capability of the bioimpedance based method for assessing the wound status. In the future measurements with the method should be extended to concern hard-to-heal wounds.

  11. Wound healing and antibacterial activities of chondroitin sulfate- and acharan sulfate-reduced silver nanoparticles

    International Nuclear Information System (INIS)

    Im, A-Rang; Kim, Jee Young; Kim, Yeong Shik; Kim, Hyun-Seok; Cho, Seonho; Park, Youmie

    2013-01-01

    For topical applications in wound healing, silver nanoparticles (AgNPs) have attracted much attention as antibacterial agents. Herein, we describe a green-synthetic route for the production of biocompatible and crystalline AgNPs using two glycosaminoglycans, chondroitin sulfate (CS) and acharan sulfate (AS), as reducing agents. The synthetic approach avoids the use of toxic chemicals, and the yield of AgNPs formation is found to be 98.1% and 91.1% for the chondroitin sulfate-reduced silver nanoparticles (CS-AgNPs) and the acharan sulfate-reduced silver nanoparticles (AS-AgNPs), respectively. Nanoparticles with mostly spherical and amorphous shapes were observed, with an average diameter of 6.16 ± 2.26 nm for CS-AgNPs and 5.79 ± 3.10 nm for AS-AgNPs. Images of the CS-AgNPs obtained from atomic force microscopy revealed the self-assembled structure of CS was similar to a densely packed woven mat with AgNPs sprinkled on the CS. These nanoparticles were stable under cell culture conditions without any noticeable aggregation. An approximately 128-fold enhancement of the antibacterial activities of the AgNPs was observed against Enterobacter cloacae and Escherichia coli when compared to CS and AS alone. In addition, an in vivo animal model of wound healing activity was tested using mice that were subjected to deep incision wounds. In comparison to the controls, the ointments containing CS-AgNPs and AS-AgNPs stimulated wound closure under histological examination and accelerated the deposition of granulation tissue and collagen in the wound area. The wound healing activity of the ointments containing CS-AgNPs and AS-AgNPs are comparable to that of a commercial formulation of silver sulfadiazine even though the newly prepared ointments contain a lower silver concentration. Therefore, the newly prepared AgNPs demonstrate potential for use as an attractive biocompatible nanocomposite for topical applications in the treatment of wounds. (paper)

  12. Wound healing and antibacterial activities of chondroitin sulfate- and acharan sulfate-reduced silver nanoparticles

    Science.gov (United States)

    Im, A.-Rang; Kim, Jee Young; Kim, Hyun-Seok; Cho, Seonho; Park, Youmie; Kim, Yeong Shik

    2013-10-01

    For topical applications in wound healing, silver nanoparticles (AgNPs) have attracted much attention as antibacterial agents. Herein, we describe a green-synthetic route for the production of biocompatible and crystalline AgNPs using two glycosaminoglycans, chondroitin sulfate (CS) and acharan sulfate (AS), as reducing agents. The synthetic approach avoids the use of toxic chemicals, and the yield of AgNPs formation is found to be 98.1% and 91.1% for the chondroitin sulfate-reduced silver nanoparticles (CS-AgNPs) and the acharan sulfate-reduced silver nanoparticles (AS-AgNPs), respectively. Nanoparticles with mostly spherical and amorphous shapes were observed, with an average diameter of 6.16 ± 2.26 nm for CS-AgNPs and 5.79 ± 3.10 nm for AS-AgNPs. Images of the CS-AgNPs obtained from atomic force microscopy revealed the self-assembled structure of CS was similar to a densely packed woven mat with AgNPs sprinkled on the CS. These nanoparticles were stable under cell culture conditions without any noticeable aggregation. An approximately 128-fold enhancement of the antibacterial activities of the AgNPs was observed against Enterobacter cloacae and Escherichia coli when compared to CS and AS alone. In addition, an in vivo animal model of wound healing activity was tested using mice that were subjected to deep incision wounds. In comparison to the controls, the ointments containing CS-AgNPs and AS-AgNPs stimulated wound closure under histological examination and accelerated the deposition of granulation tissue and collagen in the wound area. The wound healing activity of the ointments containing CS-AgNPs and AS-AgNPs are comparable to that of a commercial formulation of silver sulfadiazine even though the newly prepared ointments contain a lower silver concentration. Therefore, the newly prepared AgNPs demonstrate potential for use as an attractive biocompatible nanocomposite for topical applications in the treatment of wounds.

  13. Silver nitrate based gel dosimeter

    International Nuclear Information System (INIS)

    Titus, D; Samuel, E J J; Srinivasan, K; Roopan, S M; Madhu, C S

    2017-01-01

    A new radiochromic gel dosimeter based on silver nitrate and a normoxic gel dosimeter was investigated using UV-Visible spectrophotometry in the clinical dose range. Gamma radiation induced the synthesis of silver nanoparticles in the gel and is confirmed from the UV-Visible spectrum which shows an absorbance peak at around 450 nm. The dose response function of the dosimeter is found to be linear upto12Gy. In addition, the gel samples were found to be stable which were kept under refrigeration. (paper)

  14. The Effect of Lithospermum officinale, Silver Sulfadiazine and Alpha Ointments in Healing of Burn Wound Injuries in Rat.

    Science.gov (United States)

    Mohtasham Amiri, Zahra; Tanideh, Nader; Seddighi, Anahita; Mokhtari, Maral; Amini, Masood; Shakouri Partovi, Alborz; Manafi, Amir; Hashemi, Seyedeh Sara; Mehrabani, Davood

    2017-09-01

    Burn is the most devastating condition in emergency medicine leading to chronic disabilities. This study aimed to compare the effect of Lithospermum officinale , silver sulfadiazine and alpha ointments on healing of burn wounds in rat. Ninety-five rats were divided into 5 groups. Group 1 just underwent burn injury, and groups 2-5 received alpha ointment, silver sulfadiazine (SSD), gel base and L. officinale extract, respectively. A hot plate was used for induction of a standard 3 rd degree burn wound. Burn wounds were macroscopically and microscopically evaluated on days 7 th , 14 th and 21 st after burn induction. A decrease in the number of inflammatory cells was noted when L. officinale and SSD were applied while the most inflammatory response was seen after administration of alpha ointment. The number of macrophages alone decreased after burn injury, while the frequency was the most when L. officinale and alpha ointment were applied. Re-epithelialization, angiogenesis and formation of granulation tissue were the best in relation to L. officinale and alpha ointment while, the worst results belonged to burn injury group and SSD regarding granulation tissue formation. Considering histological assessment, the best results were observed for scoring of inflammation, re-epithelialization, angiogenesis, formation of granulation tissue and number of macrophage when L. officinale and alpha ointment were used after burn injury. It can be concluded that topical application of L. officinale as a non-toxic, inexpensive and easy to produce herbal can lead to a rapid epithelialization and wound healing and these findings can be added to the literature on burn wound healing.

  15. Preparation of silver-chitosan nanocomposites and coating on bandage for antibacterial wound dressing application

    Energy Technology Data Exchange (ETDEWEB)

    Susilowati, Endang, E-mail: endwati@yahoo.co.id; Ashadi [Chemistry Education Department, Faculty of Teacher Training and Education, Universitas Sebelas Maret Surakarta (Indonesia); Maryani [Medical Doctor Program, Faculty of Medicine, Universitas Sebelas Maret Surakarta, Indonesia Jl. Ir Sutami 36 A Surakarta Indonesia 53126 (Indonesia)

    2016-02-08

    Bandage is a medical device that is essential for wound dressing. To improve the performance of the bandage, it has been coated by silver-chitosan nanocomposites (Ag/Chit) with pad-dry-cure method. The nanocomposites were performed by chemical reduction method at room temperature using glucose as reducing agent, sodium hydroxide (NaOH) as accelerator reagent, silver nitrate (AgNO{sub 3}) as metal precursor and chitosan as stabilizing agent. Localized surface plasmon resonance (LSPR) absorption band of silver nanoparticles was investigated using UV-Vis spectrophotometer. The bandage coated Ag/Chit nanocomposites (B-Ag/Chit) were characterized by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope (SEM). In addition, antibacterial activity of the bandage toward Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) were also studied. The formation of silver nanoparticles was confirmed by the appearance of LSPR absorption peak at 412.2 – 423.2 nm. Coating of nanocomposite cause increasing rigidity of bandage and decreasing on crystallinity. The bandages of B-Ag/Chit demonstrated good activity against both Gram positive (S. aureus) and Gram negative (E.Coli). Thus the bandages have a potential to be used for antibacterial wound dressing application.

  16. Microwave-Assisted Synthesis of Chitosan/Polyvinyl Alcohol Silver Nanoparticles Gel for Wound Dressing Applications

    Directory of Open Access Journals (Sweden)

    Nguyen Thi Hiep

    2016-01-01

    Full Text Available The purpose of this study was to fabricate chitosan/poly(vinyl alcohol/Ag nanoparticles (CPA gels with microwave-assistance for skin applications. Microwave irradiation was employed to reduce silver ions to silver nanoparticles and to crosslink chitosan (CS with polyvinyl alcohol (PVA. The presence of silver nanoparticles in CPA gels matrix was examined using UV-Vis spectroscopy, transmission electron microscopy, and X-ray diffraction. The interaction of CS and PVA was analysed by Fourier transform infrared spectroscopy. The release of silver ions was determined by atomic absorption spectrometry. The antimicrobial properties of CPA gels against P. aeruginosa and S. aureus were investigated using agar diffusion method. Finally, the biocompatibility and wound-healing ability of the gels were studied using fibroblast cells (in vitro and mice models (in vivo. In conclusion, the results showed that CPA gels were successfully fabricated using microwave irradiation method. These gels can be applied to heal an open wound thanks to their antibacterial activity and biocompatibility.

  17. Use of a new silver barrier dressing, ALLEVYN Ag in exuding chronic wounds.

    LENUS (Irish Health Repository)

    Kotz, Paula

    2009-06-01

    Recognising and managing wounds at risk of infection is vital in wound management. ALLEVYN Ag dressings have been designed to manage exudate in chronic wounds that are at risk of infection; are displaying signs of local infection; or where a suspected increase in bacterial colonisation is delaying healing. They combine an absorbent silver sulfadiazine containing hydrocellular foam layer, with a perforated wound contact layer and highly breathable top film. The results presented are from a multi-centre clinical evaluation of 126 patients conducted to assess the performance of ALLEVYN Ag (Adhesive, Non Adhesive and Sacrum dressings) in a range of indications. Clinicians rated the dressings as acceptable for use in various wound types in 88% of patients. The majority of clinical signs of infection reduced between the initial and the final assessment. The condition of wound tissue and surrounding skin was observed to improve, and there was significant evidence of a reduction in the level of exudate from initial to final assessment (p < 0.001). Clinicians rated ALLEVYN Ag as satisfying or exceeding expectations in over 90% of patients. The evaluation showed the dressings to offer real benefits to patients and clinicians across multiple indications when used in conjunction with local protocols.

  18. Biobased silver nanocolloid coating on silk fibers for prevention of post-surgical wound infections

    Directory of Open Access Journals (Sweden)

    Dhas SP

    2015-10-01

    Full Text Available Sindhu Priya Dhas, Suruthi Anbarasan, Amitava Mukherjee, Natarajan Chandrasekaran Center for Nanobiotechnology, VIT University, Vellore, India Abstract: Bombyx mori silk fibers are an important biomaterial and are used in surgical sutures due to their remarkable biocompatibility. The major drawback to the application of biomaterials is the risk of bacterial invasion, leading to clinical complications. We have developed an easy and cost-effective method for fabrication of antibacterial silk fibers loaded with silver nanoparticles (AgNPs by an in situ and ex situ process using an aqueous extract of Rhizophora apiculata leaf. Scanning electron microscopy revealed that well dispersed nanoparticles impregnated the silk fibers both in situ and ex situ. The crystalline nature of the AgNPs in the silk fibers was demonstrated by X-ray diffraction. The thermal and mechanical properties of the silk fibers were enhanced after they were impregnated with AgNPs. The silver-coated silk fibers fabricated by the in situ and ex situ method exhibited more than 90% inhibition against Pseudomonas aeruginosa and Staphylococcus aureus. Silk fibers doped with AgNPs were found to be biocompatible with 3T3 fibroblasts. The results obtained represent an important advance towards the clinical application of biocompatible AgNP-loaded silk fibers for prevention of surgical wound infections. Keywords: silk fibers, silver nanoparticles, antibacterial activity, wound infections, cytotoxicity, 3T3 fibroblast cells

  19. Comparison of DNA Damage and Apoptosis Induced By Silver Nanoparticle-containing Dressing Materials During Wound Healing.

    Science.gov (United States)

    Choi, Young Suk; Gwak, Heui-Chul; Park, Jae Keun; Lim, Ji Yun; Yeo, Eui Dong; Park, Eunseok; Kim, Junyong; Lee, Young Koo

    2018-04-13

    Silver nanoparticle (AgNP)-containing dressings are used worldwide for the treatment of wounds; however, many studies have indicated that AgNPs are toxic to humans and cause cell death, primarily via apoptosis. In this study, the investigators compare the apoptotic effects of various AgNP dressing materials, with the hypothesis that nanosilver would be less toxic than ionic silver. For the in vivo experiments, Sprague-Dawley (SD) and streptozotocin (STZ)-induced diabetic rats were treated with 5 dressing materials: Aquacel Ag (product A, silver ion; ConvaTec, Berkshire, UK), Acticoat (product B, AgNP; Smith & Nephew, Fort Worth, TX), Medifoam Silver (product C, silver ion; Genewel Science Co Ltd, Seongnam, South Korea), PolyMem Silver (product D, AgNP; Ferris Mfg Corp, Fort Worth, TX), and Vaseline-impregnated dressing gauze (control; Unilever, London, UK). All treatments were applied 3 times per week. After 14 days of treatment, the SD and STZ rats were euthanized, and wound samples were examined for apoptosis. The analysis included immunohistochemistry, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, Western blotting, and reverse transcription polymerase chain reaction for a semiquantitative evaluation of apoptosis. The AgNP-containing dressing materials were more cytotoxic than the silver dressings. Compared with the AgNP dressing materials, no significant levels of apoptotic factors were observed in the silver dressing-treated wounds. The TUNEL staining showed that product C-dressed wounds contained the most apoptotic cells, while some apoptotic cells were observed in product B-dressed wounds. Moreover, apoptotic gene expression was altered, including a decline in B-cell lymphoma-2 and activation of caspase-3. This was most evident in wounds treated with product C. Interestingly, apoptotic gene expression was not induced in product A-treated wounds. Finally, product D had a relatively lower silver concentration and was less toxic

  20. Biosynthesis of silver nanoparticles from Catharanthus roseus leaf extract and assessing their antioxidant, antimicrobial, and wound-healing activities.

    Science.gov (United States)

    Al-Shmgani, Hanady S A; Mohammed, Wasnaa H; Sulaiman, Ghassan M; Saadoon, Ali H

    2017-09-01

    Biosynthesis of silver nanoparticles (AgNPs) from Catharanthus roseus leaf extract was carried out, and their characterization, as well as antioxidant, antimicrobial, and wound-healing activities were evaluated. Color change, UV-vis spectrum, XRD, FTIR, and AFM assessments supported the biosynthesis and characterization of AgNPs. The synthesized AgNPs showed strong in vitro antioxidant and antimicrobial activities against various pathogens. The in vivo assessment of wound healing in AgNPs-treated mice revealed their effectiveness in closuring and reducing size of wounds. Such potent bioactivity may justify their biomedical use as antioxidant and antimicrobial agents for controlling various health-related diseases, particularly in wound healing.

  1. Mechanical properties and in vitro characterization of polyvinyl alcohol-nano-silver hydrogel wound dressings.

    Science.gov (United States)

    Oliveira, R N; Rouzé, R; Quilty, B; Alves, G G; Soares, G D A; Thiré, R M S M; McGuinness, G B

    2014-02-06

    Polyvinyl alcohol (PVA) hydrogels are materials for potential use in burn healing. Silver nanoparticles can be synthesized within PVA hydrogels giving antimicrobial hydrogels. Hydrogels have to be swollen prior to their application, and the common medium available for that in hospitals is saline solution, but the hydrogel could also take up some of the wound's fluid. This work developed gamma-irradiated PVA/nano-Ag hydrogels for potential use in burn dressing applications. Silver nitrate (AgNO3) was used as nano-Ag precursor agent. Saline solution, phosphate-buffered solution (PBS) pH 7.4 and solution pH 4.0 were used as swelling media. Microstructural evaluation revealed an effect of the nanoparticles on PVA crystallization. The swelling of the PVA-Ag samples in solution pH 4.0 was low, as was their silver delivery, compared with the equivalent samples swollen in the other media. The highest swelling and silver delivery were related to samples prepared with 0.50% AgNO3, and they also presented lower strength in PBS pH 7.4 and solution pH 4.0. Both PVA-Ag samples were also non-toxic and presented antimicrobial activity, confirming that 0.25% AgNO3 concentration is sufficient to establish an antimicrobial effect. Both PVA-Ag samples presented suitable mechanical and swelling properties in all media, representative of potential burn site conditions.

  2. Impregnation of silver sulfadiazine into bacterial cellulose for antimicrobial and biocompatible wound dressing

    International Nuclear Information System (INIS)

    Luan, Jiabin; Wu, Jian; Zheng, Yudong; Wang, Guojie; Guo, Jia; Ding, Xun; Song, Wenhui

    2012-01-01

    Silver sulfadiazine (SSD) is a useful antimicrobial agent for wound treatment. However, recent findings indicate that conventional SSD cream has several drawbacks for use in treatments. Bacterial cellulose (BC) is a promising material for wound dressing due to its outstanding properties of holding water, strength and degradability. Unfortunately, BC itself exhibits no antimicrobial activity. A combination of SSD and BC is envisaged to form a new class of wound dressing with both antimicrobial activity and biocompatibility, which has not been reported to date. To achieve antimicrobial activity, SSD particles were impregnated into BC by immersing BC into SSD suspension after ultrasonication, namely SSD–BC. Parameters influencing SSD–BC impregnation were systematically studied. Optimized conditions of sonication time for no less than 90 min and the proper pH value between 6.6 and 9.0 were suggested. The absorption of SSD onto the BC nanofibrous network was revealed by XRD and SEM analyses. The SSD–BC membranes exhibited significant antimicrobial activities against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus evaluated by the disc diffusion method. In addition, the favorable biocompatibility of SSD–BC was verified by MTT colorimetry, epidermal cell counting method and optical microscopy. The results demonstrate the potential of SSD–BC membranes as a new class of antimicrobial and biocompatible wound dressing. (paper)

  3. Low concentrations of silver nanoparticles have a beneficial effect on wound healing in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Ambrožová, Nikola [Palacký University, Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry (Czech Republic); Zálešák, Bohumil [University Hospital Olomouc, Department of Plastic and Aesthetic Surgery (Czech Republic); Ulrichová, Jitka [Palacký University, Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry (Czech Republic); Čížková, Kateřina [Palacký University, Department of Histology and Embryology, Faculty of Medicine and Dentistry (Czech Republic); Galandáková, Adéla, E-mail: galandakova.a@seznam.cz [Palacký University, Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry (Czech Republic)

    2017-03-15

    Silver has been used in medical application for its antibacterial, antifungal, and anti-inflammatory effects. Silver nanoparticles (AgNPs) are currently in the spotlight. It was shown that their application can be useful in the management of wounds. Our study was conducted to determine whether AgNPs (average size 10.43 ± 4.74 nm) and ionic silver (Ag-I) could affect the wound healing in the in vitro model of normal human dermal fibroblasts (NHDF). We evaluated their effect on reactive oxygen species (ROS) generation and the expression of key transcription factors that coordinate the cellular response to oxidative stress [nuclear factor (erythroid-derived 2)-like 2 (Nrf2)] and inflammation [nuclear factor-κB (NF-κB)], expression of heme oxygenase-1 (HO-1), and interleukin-6 (IL-6) level. Isolated primary NHDF were scratched, heated (1 h; 42 °C), and cultured with AgNPs (0.25, 2.5, and 25 μg/ml) and Ag-I (0.025, 0.1, and 0.25 μg/ml) for 8 or 24 h. The ROS generation, Nrf2, NF-κB, and HO-1 protein expression and IL-6 protein level were then evaluated by standard methods. Non-cytotoxic concentrations of AgNPs (0.25 and 2.5 μg/ml) did not affect the ROS generation but activated the Nrf2/HO-1 pathway and decreased the NF-κB expression and IL-6 level in the in vitro wound healing model. AgNPs at concentrations of 0.25 and 2.5 μg/ml seem to be suitable for the intended application as a topical agent for wound healing, although the gene silencing technique, chemical inhibitors, and detailed time- and concentration-dependent experiments are needed for a comprehensive study of signaling pathway regulation. Further investigation is also necessary to exclude any possible adverse effects.

  4. Low concentrations of silver nanoparticles have a beneficial effect on wound healing in vitro

    International Nuclear Information System (INIS)

    Ambrožová, Nikola; Zálešák, Bohumil; Ulrichová, Jitka; Čížková, Kateřina; Galandáková, Adéla

    2017-01-01

    Silver has been used in medical application for its antibacterial, antifungal, and anti-inflammatory effects. Silver nanoparticles (AgNPs) are currently in the spotlight. It was shown that their application can be useful in the management of wounds. Our study was conducted to determine whether AgNPs (average size 10.43 ± 4.74 nm) and ionic silver (Ag-I) could affect the wound healing in the in vitro model of normal human dermal fibroblasts (NHDF). We evaluated their effect on reactive oxygen species (ROS) generation and the expression of key transcription factors that coordinate the cellular response to oxidative stress [nuclear factor (erythroid-derived 2)-like 2 (Nrf2)] and inflammation [nuclear factor-κB (NF-κB)], expression of heme oxygenase-1 (HO-1), and interleukin-6 (IL-6) level. Isolated primary NHDF were scratched, heated (1 h; 42 °C), and cultured with AgNPs (0.25, 2.5, and 25 μg/ml) and Ag-I (0.025, 0.1, and 0.25 μg/ml) for 8 or 24 h. The ROS generation, Nrf2, NF-κB, and HO-1 protein expression and IL-6 protein level were then evaluated by standard methods. Non-cytotoxic concentrations of AgNPs (0.25 and 2.5 μg/ml) did not affect the ROS generation but activated the Nrf2/HO-1 pathway and decreased the NF-κB expression and IL-6 level in the in vitro wound healing model. AgNPs at concentrations of 0.25 and 2.5 μg/ml seem to be suitable for the intended application as a topical agent for wound healing, although the gene silencing technique, chemical inhibitors, and detailed time- and concentration-dependent experiments are needed for a comprehensive study of signaling pathway regulation. Further investigation is also necessary to exclude any possible adverse effects.

  5. Comparison of two silver dressings for wound management in pediatric burns.

    Science.gov (United States)

    Jester, Ingo; Bohn, Ingo; Hannmann, Thorsten; Waag, Karl-Ludwig; Loff, Steffan

    2008-11-01

    Purpose. Silver wound dressings are widely used in the treatment of burns. Dressings differ in material characteristics, various antimicrobial activities, and ease of use. The purpose of this study was to evaluate both dressing performance and amount of pain during the dressing changes of 2 silver dressings Urgotul SSD® (Laboratoires Urgo, Chenove, France), and Contreet Ag® (Coloplast, Minneapolis, MN) in children. A retrospective cohort study was performed with 2 groups of 20 burns treated with Urgotul SSD and Contreet Ag until the wounds were healed or grafted. Seventy dressing changes in the Contreet Ag group and 67 dressing changes in the Urgotul group were evaluated. Every dressing change was assessed regarding the dressing performance (exudate, adherence, bleeding, and dressing application/removal), and pain. Pain was "absent or slight" in 61 (92%) dressing changes with Urgotul SSD, and in 60 (85%) of the dressing changes with Contreet Ag. Dressing application in the Urgotul group was more often "very easy" (n = 33; 49%) or "easy" (n = 32; 48%) than in the Contreet Ag group, "very easy" (n = 25; 35%), and "easy" (n = 42; 60%). Contreet Ag had a greater ability to absorb exudate ("very good" n = 60; 85%, and "good" n = 11; 15%) than Urgotul SSD ("very good" n = 34; 51%, and "good" n = 13; 19%). Urgotul SSD and Contreet Ag are comparable regarding pain during dressing change. The dressings differ in their ability to absorb exudate and ease of application. Both dressings provided nearly painless wound management, and therefore were highly accepted by the nurses and especially the children being treated.

  6. Amelioration of excision wounds by topical application of green synthesized, formulated silver and gold nanoparticles in albino Wistar rats.

    Science.gov (United States)

    Naraginti, Saraschandra; Kumari, P Lakshmi; Das, Raunak Kumar; Sivakumar, A; Patil, Sagar Hindurao; Andhalkar, Vaibhav Vilas

    2016-05-01

    Wound healing, a complex biological process, has attained a lot of attention as dermatologists are primarily interested in stimulated wound closure without formation of scar or a faint scar. The recent upsurgence of nanotechnology has provided novel therapeutic materials in the form of silver and gold nanoparticles which accelerate the wound healing process. The effect of formulated nanoparticles using Coleus forskohlii root extract (green synthesized) has been tried out for ameliorating full thickness excision wounds in albino Wistar male rats. The evaluation of in vivo activity of nanoparticles in wound healing was carried out on open wounds made by excision on the dorsal sides of albino Wistar rats under anesthesia, and the healing of the wounds was assessed. Histological aspects of the healing process were studied by a HE (Hematoxylin and Eosin) staining method to assess various degrees of re-epithelialization and the linear alignment of the granulation tissue whereas Van Gieson's histochemical staining was performed to observe collagen fibers. The healing action shown by the formulated nanoparticles was remarkable during the early stages of wound healing, which resulted in the substantial reduction of the whole healing period. Topical application of formulated gold nanoparticles was found to be more effective in suppressing inflammation and stimulating re-epithelialization compared to silver nanoparticles during the healing process. The results throw light on the amelioration of excision wounds using nanoparticles which could be a novel therapeutic way of improving wound healing in clinical practice. The mechanism of advanced healing action of both types of nanoparticles could be due to their antimicrobial, antioxidant and anti-inflammatory properties. Copyright © 2016. Published by Elsevier B.V.

  7. Clinical evaluation of a dressing with poly absorbent fibres and a silver matrix for managing chronic wounds at risk of infection: a non comparative trial.

    Science.gov (United States)

    Dalac, S; Sigal, L; Addala, A; Chahim, M; Faivre-Carrere, C; Lemdjadi, Z; Bohbot, S

    2016-09-01

    To assess the efficacy, safety and acceptability of a new silver poly absorbent dressing (UrgoCleanAg) in the local management of exudative chronic wounds at risk of infection, with inflammatory signs suggesting heavy bacterial load. This prospective, multicentre, non-comparative clinical trial was conducted in French hospital wards (dermatology and vascular medicine) or specialised private-practice physicians. Patients were considered at high-risk of infection when presenting with at least three of five selected inflammatory clinical signs, suggesting a heavy bacterial load (pain between two dressing changes, erythema, oedema, malodorous wound and presence of a heavy exudate). They were treated for a maximum period of four weeks, and followed by the physician on a weekly basis, including a clinical examination, area tracings and photographs. The primary efficacy criterion of the trial was the relative wound surface area reduction at the end of the four weeks of treatment. Acceptability was documented by the nursing staff at each dressing change between the weekly evaluations. We recruited 37 patients with chronic wounds. Wound surface area, mostly covered by sloughy tissue, was reduced by 32.5% at the end of the treatment (median value), while the clinical score (maximum value of 5, based on inflammatory clinical signs) decreased from 4.0 to 2.0. Effective debridement properties were documented (62.5% relative reduction of sloughy tissue at week 4; 58.8% of debrided wounds at week 4) and improvement of the periwound skin status was noted (healthy for 28.6% of the patients at week 4 versus 2.7% at baseline). In addition, the tested wound dressing presented a good safety profile associated to a high level of acceptability, noted by both patients and nursing staff. These clinical data support that the tested dressing is a credible therapeutic alternative for the management of chronic wounds at risk of infection with inflammatory signs suggesting heavy bacterial load.

  8. A Comparison of Healing Effects of Propolis and Silver Sulfadiazine on Full Thickness Skin Wounds in Rats

    Directory of Open Access Journals (Sweden)

    E. Moghtaday Khorasgani*, A. H. Karimi and M. R. Nazem

    2010-04-01

    Full Text Available Healing effects of propolis and silver sulfadiazine (SS on skin wounds in rats were compared using qualitative and quantitative parameters and histopathological findings. A total of 30 full thickness skin wounds were created on dorsal aspects of 10 rats; i.e., three wounds on each rat. Of these wounds, 10 each were allocated to group A (propolis, group B (SS and group C (control. The skin wounds in the rats of groups A, B and C were covered daily for 14 days with 50% propolis cream, SS skin cream and bepanthane cream (control, respectively. Postoperatively, the wound surfaces were examined macroscopically and the healing process and the rates of wound expansion, contraction and epithelialization processes were quantitatively analyzed. As a result, propolis was found in general to have a better wound healing effect than others. At the 10th day of experiment histopathologically, there was inflammatory reaction with infiltration of lymphocytes, macrophages and neutrophils and proliferation of fibroblastic loose connective tissue in dermis of rats of all groups. The severity of these changes was lower in propolis treated group compared to other two groups.

  9. Linseed hydrogel-mediated green synthesis of silver nanoparticles for antimicrobial and wound-dressing applications.

    Science.gov (United States)

    Haseeb, Muhammad Tahir; Hussain, Muhammad Ajaz; Abbas, Khawar; Youssif, Bahaa Gm; Bashir, Sajid; Yuk, Soon Hong; Bukhari, Syed Nasir Abbas

    2017-01-01

    Polysaccharides are being extensively employed for the synthesis of silver nanoparticles (Ag NPs) having diverse morphology and applications. Herein, we present a novel and green synthesis of Ag NPs without using any physical reaction conditions. Linseed hydrogel (LSH) was used as a template to reduce Ag + to Ag 0 . AgNO 3 (10, 20, and 30 mmol) solutions were mixed with LSH suspension in deionized water and exposed to diffused sunlight. Reaction was monitored by noting the change in the color of reaction mixture up to 10 h. Ag NPs showed characteristic ultraviolet-visible (UV/Vis) absorptions from 410 to 437 nm in the case of sunlight and 397-410 nm in the case of temperature study. Transmission electron microscopy images revealed the formation of spherical Ag NPs in the range of 10-35 nm. Face-centered cubic array of Ag NPs was confirmed by characteristic diffraction peaks in powder X-ray diffraction spectrum. Ag NPs were stored in LSH thin films, and UV/Vis spectra recorded after 6 months indicated that Ag NPs retained their texture over the storage period. Significant antimicrobial activity was observed when microbial cultures (bacteria and fungi) were exposed to the synthesized Ag NPs. Wound-healing studies revealed that Ag NP-impregnated LSH thin films could have potential applications as an antimicrobial dressing in wound management procedures.

  10. Plasmonic characterization of photo-induced silver nanoparticles extracted from silver halide based TEM film

    Energy Technology Data Exchange (ETDEWEB)

    Sudheer,, E-mail: sudheer@rrcat.gov.in; Tiwari, P.; Rai, V. N.; Srivastava, A. K. [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India); Varshney, G. K. [Laser Bio-medical Applications & Instrumentation Division, Raja Ramanna Centre for Advanced Technology Indore, Madhya Pradesh 452013 (India)

    2016-05-23

    The plasmonic responses of silver nanoparticles extracted from silver halide based electron microscope film are investigated. Photo-reduction process is carried out to convert the silver halide grains into the metallic silver. The centrifuge technique is used for separating the silver nanoparticles from the residual solution. Morphological study performed by field emission scanning electron microscope (FESEM) shows that all the nanoparticles have an average diameter of ~120 nm with a high degree of mono dispersion in size. The localized surface plasmon resonance (LSPR) absorption peak at ~537 nm confirms the presence of large size silver nanoparticles.

  11. A comparative study to evaluate the effect of honey dressing and silver sulfadiazene dressing on wound healing in burn patients

    Directory of Open Access Journals (Sweden)

    Baghel P

    2009-01-01

    Full Text Available To compare the effect of honey dressing and silver-sulfadiazene (SSD dressing on wound healing in burn patients. Patients (n=78 of both sexes, with age group between 10 and 50 years and with first and second degree of burn of less than 50% of TBSA (Total body surface area were included in the study, over a period of 2 years (2006-08. After stabilization, patients were randomly attributed into two groups: ′honey group′ and ′SSD group′. Time elapsed since burn was recorded. After washing with normal saline, undiluted pure honey was applied over the wounds of patients in the honey group (n=37 and SSD cream over the wounds of patients in SSD group (n=41, everyday. Wound was dressed with sterile gauze, cotton pads and bandaged. Status of the wound was assessed every third and seventh day and on the day of completion of study. Patients were followed up every fortnight till epithelialization. The bacteriological examination of the wound was done every seventh day. The mean age for case (honey group and control (SSD group was 34.5 years and 28.5 years, respectively. Wound swab culture was positive in 29 out of 36 patients who came within 8 hours of burn and in all patients who came after 24 hours. The average duration of healing in patients treated with honey and SSD dressing at any time of admission was 18.16 and 32.68 days, respectively. Wound of all those patients (100% who reported within 1 hour became sterile with honey dressing in less than 7 days while none with SSD. All of the wounds became sterile in less than 21 days with honey, while tthis was so in only 36.5% with SSD treated wounds. The honey group included 33 patients reported within 24 hour of injury, and 26 out of them had complete outcome at 2 months of follow-up, while numbers for the SSD group were 32 and 12. Complete outcome for any admission point of time after 2 months was noted in 81% and 37% of patients in the honey group and the SSD group. Honey dressing improves wound

  12. Polystyrene Based Silver Selective Electrodes

    Directory of Open Access Journals (Sweden)

    Shiva Agarwal

    2002-06-01

    Full Text Available Silver(I selective sensors have been fabricated from polystyrene matrix membranes containing macrocycle, Me6(14 diene.2HClO4 as ionophore. Best performance was exhibited by the membrane having a composition macrocycle : Polystyrene in the ratio 15:1. This membrane worked well over a wide concentration range 5.0×10-6–1.0×10-1M of Ag+ with a near-Nernstian slope of 53.0 ± 1.0 mV per decade of Ag+ activity. The response time of the sensor is <15 s and the membrane can be used over a period of four months with good reproducibility. The proposed electrode works well in a wide pH range 2.5-9.0 and demonstrates good discriminating power over a number of mono-, di-, and trivalent cations. The sensor has also been used as an indicator electrode in the potentiometric titration of silver(II ions against NaCl solution. The sensor can also be used in non-aqueous medium with no significant change in the value of slope or working concentration range for the estimation of Ag+ in solution having up to 25% (v/v nonaqueous fraction.

  13. Influence of hydrophilic polymers on functional properties and wound healing efficacy of hydrocolloid based wound dressings.

    Science.gov (United States)

    Jin, Sung Giu; Yousaf, Abid Mehmood; Kim, Kyeong Soo; Kim, Dong Wuk; Kim, Dong Shik; Kim, Jin Ki; Yong, Chul Soon; Youn, Yu Seok; Kim, Jong Oh; Choi, Han-Gon

    2016-03-30

    The purpose of this study was to investigate the influence of different hydrophilic polymers on the swelling, bioadhesion and mechanical strength of hydrocolloid wound dressings (HCDs) in order to provide an appropriate composition for a hydrocolloid wound dressing system. In this study, the HCDs were prepared with styrene-isoprene-styrene copolymer (SIS) and polyisobutylene (PIB) as the base using a hot melting method. Additionally, numerous SIS/PIB-based HCDs were prepared with six hydrophilic polymers, and their wound dressing properties were assessed. Finally, the wound healing efficacy of the selected formulations was compared to a commercial wound dressing. The swelling ratio, bioadhesive force and mechanical strengths of HCDs were increased in the order of sodium alginate>sodium CMC=poloxamer=HPMC>PVA=PVP, sodium alginate>sodium CMC=poloxamer>PVA>HPMC=PVP and sodium alginate≥PVA>PVP=HPMC=sodium CMC>poloxamer, respectively. Among the hydrophilic polymers tested, sodium alginate most enhanced the swelling capacity, bioadhesive force and mechanical strengths. Thus, the hydrophilic polymers played great role in the swelling, bioadhesion and mechanical strength of SIS/PIB-based HCDs. The HCD formulation composed of PIB, SIS, liquid paraffin and sodium alginate at the weight ratio of 20/25/12/43 gave better wound dressing properties and more excellent wound healing efficacy than the commercial wound dressing. Therefore, the novel HCD formulation could be a promising hydrocolloid system for wound dressings. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. In Situ Synthesis of Antimicrobial Silver Nanoparticles within Antifouling Zwitterionic Hydrogels by Catecholic Redox Chemistry for Wound Healing Application.

    Science.gov (United States)

    GhavamiNejad, Amin; Park, Chan Hee; Kim, Cheol Sang

    2016-03-14

    A multifunctional hydrogel that combines the dual functionality of both antifouling and antimicrobial capacities holds great potential for many bioapplications. Many approaches and different materials have been employed to synthesize such a material. However, a systematic study, including in vitro and in vivo evaluation, on such a material as wound dressings is highly scarce at present. Herein, we report on a new strategy that uses catecholic chemistry to synthesize antimicrobial silver nanoparticles impregnated into antifouling zwitterionic hydrogels. For this purpose, hydrophobic dopamine methacrylamide monomer (DMA) was mixed in an aqueous solution of sodium tetraborate decahydrate and DMA monomer became soluble after increasing pH to 9 due to the complexation between catechol groups and boron. Then, cross-linking polymerization of zwitterionic monomer was carried out with the solution of the protected dopamine monomer to produce a new hydrogel. When this new hydrogel comes in contact with a silver nitrate solution, silver nanoparticles (AgNPs) are formed in its structure as a result of the redox property of the catechol groups and in the absence of any other external reducing agent. The results obtained from TEM and XRD measurements indicate that AgNPs with diameters of around 20 nm had formed within the networks. FESEM images confirmed that the silver nanoparticles were homogeneously incorporated throughout the hydrogel network, and FTIR spectroscopy demonstrated that the catechol moiety in the polymeric backbone of the hydrogel is responsible for the reduction of silver ions into the AgNPs. Finally, the in vitro and in vivo experiments suggest that these mussel-inspired, antifouling, antibacterial hydrogels have great potential for use in wound healing applications.

  15. In vitro and in vivo investigation of bacterial cellulose dressing containing uniform silver sulfadiazine nanoparticles for burn wound healing

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Wen

    2015-06-01

    Full Text Available Silver sulfadiazine (SSD particles in homogeneous dispersion state were prepared by an ultrasonic method and then nano- and microparticles were separated using centrifugation. SSD particles with narrow size distribution were impregnated with bacterial cellulose (BC to produce BC–SSD composite membrane used as burn wound dressing. A scanning electron microscope (SEM was used to examine the surface morphology of BC–SSD membranes. The incorporation of SSD in BC–SSD was confirmed by X-ray diffraction (XRD. Antimicrobial tests in vitro indicated that BC–SSD showed excellent antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The effects of BC–SSD on burn wound healing were assessed by rat models. The comparative study confirmed that the wound treated with BC–SSD showed high healing rate. The bacteria count in BC–SSD group was far less than control group. Histological analysis showed that epithelialization progressed better in wound treated with BC–SSD. These values demonstrated that the BC–SSD composite membrane could be a promising wound dressing for burn.

  16. Low molecular weight chitosan-coated silver nanoparticles are effective for the treatment of MRSA-infected wounds

    Directory of Open Access Journals (Sweden)

    Peng Y

    2017-01-01

    Full Text Available Yinbo Peng,1 Chenlu Song,1 Chuanfeng Yang,1 Qige Guo,1 Min Yao1,2 1Department of Burns and Plastic Surgery, Shanghai Ninth People’s Hospital, Institute of Traumatic Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China; 2Department of Dermatology, Wellman Center for Photomedicine, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA Abstract: Silver nanoparticles (AgNPs are being widely applied as topical wound materials; however, accumulated deposition of silver in the liver, spleen, and other main organs may lead to organ damage and dysfunction. We report here that low molecular weight chitosan-coated silver nanoparticles (LMWC-AgNPs are effective against methicillin-resistant Staphylococcus aureus (MRSA, have better biocompatibility, and have lower body absorption characteristics when compared with polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs and silver nanoparticles without surface stabilizer (uncoated-AgNPs in a dorsal MRSA wound infection mouse model. LMWC-AgNPs were synthesized by reducing silver nitrate with low molecular weight chitosan as a stabilizer and reducing agent, while PVP-AgNPs were synthesized using polyvinylpyrrolidone as a stabilizer and ethanol as a reducing agent. AgNPs with different surface stabilizers were identified by UV-visible absorption spectrometry, and particle size was determined by transmission electron microscopy. UV-visible absorption spectra of LMWC-AgNPs, PVP-AgNPs and uncoated-AgNPs were similar and their sizes were in the range of 10–30 nm. In vitro experiments showed that the three types of AgNPs had similar MRSA-killing effects, with obvious effect at 4 µg/mL and 100% effect at 8 µg/mL. Bacteriostatic annulus experiments also showed that all the three types of AgNPs had similar antibacterial inhibitory effect at 10 µg/mL. Cell counting kit-8 assay and Hoechst/propidium iodide (PI staining showed that LMWC-AgNPs were

  17. Production of electrospun polyvinyl alcohol/microbial synthesized silver nanoparticles scaffold for the treatment of fungating wounds

    Science.gov (United States)

    Yahyaei, Behrooz; Manafi, Sahebali; Fahimi, Bijan; Arabzadeh, Sepideh; Pourali, Parastoo

    2018-03-01

    Fungating wounds usually develop in patients with advanced cancer, which responds poorly to treatments. Such wounds can be treated using suitable dressings. For this purpose, a recent research produced a new type of wound dressing with antibacterial and anticancer properties. The culture supernatant of Fusarium oxysporum was challenged with silver nitrate and heated for 5 min. Production of silver nanoparticles (SNPs) was confirmed using spectrophotometer, transmission electron microscopy (TEM), and X-ray diffraction (XRD) analysis. A solution of 10% (w/w) poly vinyl alcohol (PVA) and different volumes of SNP solutions were provided, where each solution was separately used for electrospinning. The obtained PVA/SNPs film evaluated under morphological characterization using field emission scanning electron microscope (FE-SEM) and its antibacterial and anticancer activities were measured. Results confirmed the presence of SNPs in the reaction mixture with sizes less than 50 nm, spherical and oval in shapes. FE-SEM results confirmed that SNPs were seen inside and entrapped between PVA in the PVA/SNPs membrane, composed of 50% of each material. This film had acceptable antibacterial properties against four different bacterial strains and a good anticancer activity against the human melanoma cell line (COLO 792) in contrast to the control one. A recent research introduced a new and fast biological method for the synthesis of SNPs, having acceptable antibacterial and anticancer activities. Further studies are needed to support the obtained results.

  18. In situ synthesis of silver-nanoparticles/bacterial cellulose composites for slow-released antimicrobial wound dressing.

    Science.gov (United States)

    Wu, Jian; Zheng, Yudong; Song, Wenhui; Luan, Jiabin; Wen, Xiaoxiao; Wu, Zhigu; Chen, Xiaohua; Wang, Qi; Guo, Shaolin

    2014-02-15

    Bacterial cellulose has attracted increasing attention as a novel wound dressing material, but it has no antimicrobial activity, which is one of critical skin-barrier functions in wound healing. To overcome such deficiency, we developed a novel method to synthesize and impregnate silver nanoparticles on to bacterial cellulose nanofibres (AgNP-BC). Uniform spherical silver nano-particles (10-30 nm) were generated and self-assembled on the surface of BC nano-fibers, forming a stable and evenly distributed Ag nanoparticles coated BC nanofiber. Such hybrid nanostructure prevented Ag nanoparticles from dropping off BC network and thus minimized the toxicity of nanoparticles. Regardless the slow Ag(+) release, AgNP-BC still exhibited significant antibacterial activities with more than 99% reductions in Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. Moreover, AgNP-BC allowed attachment and growth of epidermal cells with no cytotoxicity emerged. The results demonstrated that AgNP-BC could reduce inflammation and promote wound healing. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Effectiveness of Aloe Vera gel compared with 1% silver sulphadiazine cream as burn wound dressing in second degree burns.

    Science.gov (United States)

    Shahzad, Muhammad Naveed; Ahmed, Naheed

    2013-02-01

    To assess the efficacy of Aloe Vera gel compared with 1% silver sulfadiazine cream as a burn dressing for the treatment of superficial and partial thickness burns. This Interventional Comparative study was carried out at the Burn unit and Plastic surgery department, Nishtar Hospital Multan, Pakistan from July 2008 to December 2010. A total of 50 patients with superficial and partial thickness burns were divided into two equal groups randomly by consecutive sampling method, one group was dressed with Aloe Vera gel while the other was treated with 1% silversulphadiazine cream, and the results regarding duration of wound epithelialization, pain relief and cost of treatment were compared. In patients treated with Aloe Vera gel, healing of burn wounds were remarkably early than those patients treated with 1% silver sulfadiazine. All the patients of Aloe Vera group were relieved of pain earlier than those patients who were treated with SSD. Thermal burns patients dressed with Aloe Vera gel showed advantage compared to those dressed with SSD regarding early wound epithelialization, earlier pain relief and cost-effectiveness.

  20. A comparative study to evaluate the effect of honey dressing and silver sulfadiazene dressing on wound healing in burn patients

    OpenAIRE

    Baghel, P. S.; Shukla, S.; Mathur, R. K.; Randa, R.

    2009-01-01

    To compare the effect of honey dressing and silver-sulfadiazene (SSD) dressing on wound healing in burn patients. Patients (n=78) of both sexes, with age group between 10 and 50 years and with first and second degree of burn of less than 50% of TBSA (Total body surface area) were included in the study, over a period of 2 years (2006-08). After stabilization, patients were randomly attributed into two groups: ?honey group? and ?SSD group?. Time elapsed since burn was recorded. After washing wi...

  1. Silver distribution and release from an antimicrobial denture base resin containing silver colloidal nanoparticles.

    Science.gov (United States)

    Monteiro, Douglas Roberto; Gorup, Luiz Fernando; Takamiya, Aline Satie; de Camargo, Emerson Rodrigues; Filho, Adhemar Colla Ruvolo; Barbosa, Debora Barros

    2012-01-01

    The aim of this study was to evaluate a denture base resin containing silver colloidal nanoparticles through morphological analysis to check the distribution and dispersion of these particles in the polymer and by testing the silver release in deionized water at different time periods. A Lucitone 550 denture resin was used, and silver nanoparticles were synthesized by reduction of silver nitrate with sodium citrate. The acrylic resin was prepared in accordance with the manufacturers' instructions, and silver nanoparticle suspension was added to the acrylic resin monomer in different concentrations (0.05, 0.5, and 5 vol% silver colloidal). Controls devoid of silver nanoparticles were included. The specimens were stored in deionized water at 37°C for 7, 15, 30, 60, and 120 days, and each solution was analyzed using atomic absorption spectroscopy. Silver was not detected in deionized water regardless of the silver nanoparticles added to the resin and of the storage period. Micrographs showed that with lower concentrations, the distribution of silver nanoparticles was reduced, whereas their dispersion was improved in the polymer. Moreover, after 120 days of storage, nanoparticles were mainly located on the surface of the nanocomposite specimens. Incorporation of silver nanoparticles in the acrylic resin was evidenced. Moreover, silver was not detected by the detection limit of the atomic absorption spectrophotometer used in this study, even after 120 days of storage in deionized water. Silver nanoparticles are incorporated in the PMMA denture resin to attain an effective antimicrobial material to help control common infections involving oral mucosal tissues in complete denture wearers. © 2011 by the American College of Prosthodontists.

  2. Development of novel wound care systems based on nanosilver nanohydrogels of polymethacrylic acid with Aloe vera and curcumin.

    Science.gov (United States)

    Anjum, Sadiya; Gupta, Amlan; Sharma, Deepika; Gautam, Deepti; Bhan, Surya; Sharma, Anupama; Kapil, Arti; Gupta, Bhuvanesh

    2016-07-01

    This study is aimed at the development of a composite material for wound dressing containing nanosilver nanohydrogels (nSnH) along with Aloe vera and curcumin that promote antimicrobial nature, wound healing and infection control. Nanosliver nanohydrogels were synthesized by nanoemulsion polymerization of methacrylic acid (MAA) followed by subsequent crosslinking and silver reduction under irradiation. Both the polymerization and irradiation time had significant influence on the nanoparticle shape, size and its formation. Polyvinyl alcohol/polyethylene oxide/carboxymethyl cellulose matrix was used as gel system to blend with nSnH, A. vera, curcumin and coat it on the hydrolysed PET fabric to develop antimicrobial dressings. The cumulative release of silver from the dressing was found to be ~42% of the total loading after 48h. The antimicrobial activity of the dressings was studied against both Staphylococcus aureus and Escherichia coli. In vivo wound healing studies were carried out over a period of 16d on full-thickness skin wounds created on Swiss albino mice. Fast healing was observed in Gel/nSnH/Aloe treated wounds with minimum scarring, as compared to other groups. The histological studies showed A. vera based dressings to be the most optimum one. These results suggest that nSnH along with A. vera based dressing material could be promising candidates for wound dressings. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Filament wound data base development, revision 1

    Science.gov (United States)

    Sharp, R. Scott; Braddock, William F.

    1985-01-01

    The objective was to update the present Space Shuttle Solid Rocket Booster (SRB) baseline reentry aerodynamic data base and to develop a new reentry data base for the filament wound case SRB along with individual protuberance increments. Lockheed's procedures for performing these tasks are discussed. Free fall of the SRBs after separation from the Space Shuttle Launch Vehicle is completely uncontrolled. However, the SRBs must decelerate to a velocity and attitude that is suitable for parachute deployment. To determine the SRB reentry trajectory parameters, including the rate of deceleration and attitude history during free-fall, engineers at Marshall Space Flight Center are using a six-degree-of-freedom computer program to predict dynamic behavior. Static stability aerodynamic coefficients are part of the information required for input into this computer program. Lockheed analyzed the existing reentry aerodynamic data tape (Data Tape 5) for the current steel case SRB. This analysis resulted in the development of Data Tape 7.

  4. Gross and histologic evaluation of effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product on experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana).

    Science.gov (United States)

    Cusack, Lara M; Mayer, Joerg; Cutler, Daniel C; Rissi, Daniel R; Divers, Stephen J

    2018-04-01

    OBJECTIVE To assess effects of photobiomodulation, silver sulfadiazine, and a topical antimicrobial product for the treatment of experimentally induced full-thickness skin wounds in green iguanas (Iguana iguana). ANIMALS 16 healthy subadult green iguanas. PROCEDURES Iguanas were anesthetized, and three 5-mm cutaneous biopsy specimens were obtained from each iguana (day 0). Iguanas were randomly assigned to 2 treatment groups, each of which had a control treatment. Wounds in the topical treatment group received silver sulfadiazine, a topical antimicrobial product, or no treatment. Wounds in the laser treatment group received treatment with a class 4 laser at 5 or 10 J/cm 2 or no treatment. Wound measurements were obtained daily for 14 days. Iguanas were euthanized, and treatment sites were evaluated microscopically to detect ulceration, bacterial contamination, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity. RESULTS On day 14, wounds treated with a laser at 10 J/cm 2 were significantly smaller than those treated with silver sulfadiazine, but there were no other significant differences among treatments. Histologically, there were no significant differences in ulceration, bacterial infection, reepithelialization, necrosis, inflammation, fibrosis, and collagen maturity among treatments. CONCLUSIONS AND CLINICAL RELEVANCE Photobiomodulation at 10 J/cm 2 appeared to be a safe treatment that was tolerated well by green iguanas, but it did not result in substantial improvement in histologic evidence of wound healing, compared with results for other treatments or no treatment.

  5. Development of novel wound care systems based on nanosilver nanohydrogels of polymethacrylic acid with Aloe vera and curcumin

    Energy Technology Data Exchange (ETDEWEB)

    Anjum, Sadiya [Bioengineering Laboratory, Department of Textile Technology, Indian Institute of Technology, New Delhi 110016 (India); Gupta, Amlan; Sharma, Deepika [Department of Pathology, Sikkim Manipal Institute of Medical Sciences, Sikkim Manipal University, Gangtok 737102 (India); Gautam, Deepti [Bioengineering Laboratory, Department of Textile Technology, Indian Institute of Technology, New Delhi 110016 (India); Bhan, Surya; Sharma, Anupama [Department of Biochemistry, North Eastern Hill University, Shillong 793022, Meghalaya (India); Kapil, Arti [Department of Microbiology, All India Institute of Medical Sciences, New Delhi 110029 (India); Gupta, Bhuvanesh, E-mail: bgupta@textile.iitd.ernet.in [Bioengineering Laboratory, Department of Textile Technology, Indian Institute of Technology, New Delhi 110016 (India)

    2016-07-01

    This study is aimed at the development of a composite material for wound dressing containing nanosilver nanohydrogels (nSnH) along with Aloe vera and curcumin that promote antimicrobial nature, wound healing and infection control. Nanosliver nanohydrogels were synthesized by nanoemulsion polymerization of methacrylic acid (MAA) followed by subsequent crosslinking and silver reduction under irradiation. Both the polymerization and irradiation time had significant influence on the nanoparticle shape, size and its formation. Polyvinyl alcohol/polyethylene oxide/carboxymethyl cellulose matrix was used as gel system to blend with nSnH, A. vera, curcumin and coat it on the hydrolysed PET fabric to develop antimicrobial dressings. The cumulative release of silver from the dressing was found to be ~ 42% of the total loading after 48 h. The antimicrobial activity of the dressings was studied against both Staphylococcus aureus and Escherichia coli. In vivo wound healing studies were carried out over a period of 16 d on full-thickness skin wounds created on Swiss albino mice. Fast healing was observed in Gel/nSnH/Aloe treated wounds with minimum scarring, as compared to other groups. The histological studies showed A. vera based dressings to be the most optimum one. These results suggest that nSnH along with A. vera based dressing material could be promising candidates for wound dressings. - Highlights: • PMAA based nanosilver nanogels offer excellent antimicrobial property. • nSnH may be coated on a fabric surface to develop wound care dressings. • Dressings show good wound recovery on animal models. • Aloe vera shows better healing behaviour as compared to the curcumin based systems.

  6. Development of novel wound care systems based on nanosilver nanohydrogels of polymethacrylic acid with Aloe vera and curcumin

    International Nuclear Information System (INIS)

    Anjum, Sadiya; Gupta, Amlan; Sharma, Deepika; Gautam, Deepti; Bhan, Surya; Sharma, Anupama; Kapil, Arti; Gupta, Bhuvanesh

    2016-01-01

    This study is aimed at the development of a composite material for wound dressing containing nanosilver nanohydrogels (nSnH) along with Aloe vera and curcumin that promote antimicrobial nature, wound healing and infection control. Nanosliver nanohydrogels were synthesized by nanoemulsion polymerization of methacrylic acid (MAA) followed by subsequent crosslinking and silver reduction under irradiation. Both the polymerization and irradiation time had significant influence on the nanoparticle shape, size and its formation. Polyvinyl alcohol/polyethylene oxide/carboxymethyl cellulose matrix was used as gel system to blend with nSnH, A. vera, curcumin and coat it on the hydrolysed PET fabric to develop antimicrobial dressings. The cumulative release of silver from the dressing was found to be ~ 42% of the total loading after 48 h. The antimicrobial activity of the dressings was studied against both Staphylococcus aureus and Escherichia coli. In vivo wound healing studies were carried out over a period of 16 d on full-thickness skin wounds created on Swiss albino mice. Fast healing was observed in Gel/nSnH/Aloe treated wounds with minimum scarring, as compared to other groups. The histological studies showed A. vera based dressings to be the most optimum one. These results suggest that nSnH along with A. vera based dressing material could be promising candidates for wound dressings. - Highlights: • PMAA based nanosilver nanogels offer excellent antimicrobial property. • nSnH may be coated on a fabric surface to develop wound care dressings. • Dressings show good wound recovery on animal models. • Aloe vera shows better healing behaviour as compared to the curcumin based systems.

  7. Silver nanoparticles delivery system based on natural rubber latex membranes

    International Nuclear Information System (INIS)

    Guidelli, Éder José; Kinoshita, Angela; Ramos, Ana Paula; Baffa, Oswaldo

    2013-01-01

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV–Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane (∼0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are sterically

  8. Silver nanoparticles delivery system based on natural rubber latex membranes

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, Eder Jose, E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo/FFCLRP-DF (Brazil); Kinoshita, Angela [Universidade do Sagrado Coracao (Brazil); Ramos, Ana Paula [Universidade de Sao Paulo/FFCLRP-DQ (Brazil); Baffa, Oswaldo [Universidade de Sao Paulo/FFCLRP-DF (Brazil)

    2013-04-15

    The search for new materials for biomedical applications is extremely important. Here, we present results on the performance of a silver nanoparticles delivery system using natural rubber latex (NRL) as the polymeric matrix. Our aim was to obtain an optimized wound dressing by combining materials with potential healing action. The synthesis of silver nanoparticles and their characterization by UV-Vis spectroscopy, transmission electron microscopy, zeta potential, dynamic light scattering, and Fourier transform infrared spectroscopy (FTIR) are depicted. The NRL membranes are good matrix for silver nanoparticles and allow for their gradual release. The release of 30 nm silver nanoparticles by the NRL membranes depends on their mass percentage in NRL membranes. The total concentration of AgNP released by the NRL membranes was calculated. The AgNP attached to the cis-isoprene molecules in the NRL matrix remain attached to the membrane ({approx}0.1 % w/w). So, only the AgNP bound to the non-rubber molecules are released. FTIR spectra suggest that non-rubber molecules, like aminoacids and proteins, associated with the serum fraction of the NRL may be attached to the surfaces of the released nanoparticles, thereby increasing the release of such molecules. The released silver nanoparticles are sterically stabilized, more stable and well dispersed. Because the serum fraction of the NRL is responsible for the angiogenic properties of the matrix, the silver nanoparticles could increment the angiogenic properties of NRL. This biomaterial has desirable properties for the fabrication of a wound dressing with potential healing action, since it combines the angiogenic and antibacterial properties of the silver nanoparticles with the increased angiogenic properties of the NRL.Graphical AbstractThe AgNP attached to the cis-isoprene molecules remain in the NRL matrix and only the AgNP bound to the non-rubber molecules (NRL serum fraction) are released. The released AgNP are

  9. Naturally Occurring Wound Healing Agents: An Evidence-Based Review.

    Science.gov (United States)

    Karapanagioti, E G; Assimopoulou, A N

    2016-01-01

    Nature constitutes a pool of medicines for thousands of years. Nowadays, trust in nature is increasingly growing, as many effective medicines are naturally derived. Over the last decades, the potential of plants as wound healing agents is being investigated. Wounds and ulcers affect the patients' life quality and often lead to amputations. Approximately 43,000,000 patients suffer from diabetic foot ulcers worldwide. Annually, $25 billion are expended for the treatment of chronic wounds, with the number growing due to aging population and increased incidents of diabetes and obesity. Therefore a timely, orderly and effective wound management and treatment is crucial. This paper aims to systematically review natural products, mainly plants, with scientifically well documented wound healing activity, focusing on articles based on animal and clinical studies performed worldwide and approved medicinal products. Moreover, a brief description of the wound healing mechanism is presented, to provide a better understanding. Although a plethora of natural products are in vitro and in vivo evaluated for wound healing activity, only a few go through clinical trials and even fewer launch the market as approved medicines. Most of them rely on traditional medicine, indicating that ethnopharmacology is a successful strategy for drug development. Since only 6% of plants have been systematically investigated pharmacologically, more intensified efforts and emerging advancements are needed to exploit the potentials of nature for the development of novel medicines. This paper aims to provide a reliable database and matrix for thorough further investigation towards the discovery of wound healing agents.

  10. In vivo performance of chitosan/soy-based membranes as wound-dressing devices for acute skin wounds.

    Science.gov (United States)

    Santos, Tírcia C; Höring, Bernhard; Reise, Kathrin; Marques, Alexandra P; Silva, Simone S; Oliveira, Joaquim M; Mano, João F; Castro, António G; Reis, Rui L; van Griensven, Martijn

    2013-04-01

    Wound management represents a major clinical challenge on what concerns healing enhancement and pain control. The selection of an appropriate dressing plays an important role in both recovery and esthetic appearance of the regenerated tissue. Despite the wide range of available dressings, the progress in the wound care market relies on the increasing interest in using natural-based biomedical products. Herein, a rat wound-dressing model of partial-thickness skin wounds was used to study newly developed chitosan/soy (cht/soy)-based membranes as wound-dressing materials. Healing and repair of nondressed, cht/soy membrane-dressed, and Epigard(®)-dressed wounds were followed macroscopically and histologically for 1 and 2 weeks. cht/soy membranes performed better than the controls, promoting a faster wound repair. Re-epithelialization, observed 1 week after wounding, was followed by cornification of the outermost epidermal layer at the second week of dressing, indicating repair of the wounded tissue. The use of this rodent model, although in impaired healing conditions, may enclose some drawbacks regarding the inevitable wound contraction. Moreover, being the main purpose the evaluation of cht/soy-based membranes' performance in the absence of growth factors, the choice of a clinically relevant positive control was limited to a polymeric mesh, without any growth factor influencing skin healing/repair, Epigard. These new cht/soy membranes possess the desired features regarding healing/repair stimulation, ease of handling, and final esthetic appearance-thus, valuable properties for wound dressings.

  11. Partial-thickness burn wounds healing by topical treatment: A randomized controlled comparison between silver sulfadiazine and centiderm.

    Science.gov (United States)

    Saeidinia, Amin; Keihanian, Faeze; Lashkari, Ardalan Pasdaran; Lahiji, Hossein Ghavvami; Mobayyen, Mohammadreza; Heidarzade, Abtin; Golchai, Javad

    2017-03-01

    Burns are common event and associated with a high incidence of death, disability, and high costs. Centella asiatica (L.) is a medicinal herb, commonly growing in humid areas in several tropical countries that improve wound healing. On the basis of previous studies, we compared the efficacy of Centiderm versus silver sulfadiazine (SSD) in partial thickness burning patients. Study population comprised burn victims referred to Velayat Burning Hospital at Rasht, Iran. The intervention group received Centiderm and control group SSD cream. Burn wounds were treated once daily at home. All of the wounds were evaluated till complete healing occurred and at the admission, days 3, 7, 14 objective signs; visual acuity score (VAS) and subjective signs were recorded. Re-epithelialization time and complete healing days were recorded. We used random fixed block for randomization. The randomization sequence was created using the computer. Patients and burning specialist physician were blinded. Seventy-five patients randomized into 2 groups; (40 patients: Centiderm group; 35 patients: SSD group). The mean age of them was 30.67 ± 9.91 years and 19 of them were male (31.7%). Thirty patients in Centiderm and 30 patients in SSD group were analyzed. All of objective and subjective signs and mean of re-epithelialization and complete healing were significantly better in Centiderm group rather than SSD group (P < 0.05). There was no infection in Centiderm group. We showed that use of Centiderm ointment not only improved the objective and subjective signs in less than 3 days, but also the re-epithelialization and complete healing rather than SSD without any infection in the subjects.

  12. [ALEA study. Treatment of chronic wounds infected by the application of silver dressings nanocrystalline combined with dressings hydrocellular].

    Science.gov (United States)

    Verdú Soriano, José; Nolasco Bonmati, Andreu

    2010-10-01

    This study was conducted with the objective to assess, in real clinical conditions in primary care and geriatric centers, application and utility of nanocrystalline silver dressings dressings combined with hydrocellular in relation to the development during 20 shifts dressing or complete healing of the characteristics of the lesions included in the study Prospective observational multicenter open, repeated measures. It could include injuries of different etiologies (pressure ulcers stage 11-111, lower limb and traumatic wounds or surgical origin), with clinical signs of local infection (at least three of the following: redness, purulent discharge, heat, edema and pain). Only one wound was included per patient. An analysis of effectiveness by intention to treat all lesions included. We recruited 103 patients who met the inclusion criteria but were collected in which 77 patients were used for nanocrystalline silver dressings in some phase of the study, They had a median of 80 years of age and 58.4% were women. By type of injury: 53.2% pressure ulcers, 31.2% lower extremity ulcers and 14.3% traumatic or surgical wounds. Over 50% of the lesions was older than eight months and a larger area of 22.75 cm2. At first, 70.1% had redness, purulent discharge 64.9%, 37.7% heat edema 42.9% and 65.8% pain. Remained in the study a median of 42.5 days at a rate of change of dressing every 2.5. During this time in 96.1% of the lesions were removed for clinical signs of local infection in a statistically significant (p < or = 0.001). 27.3% healed from injuries and those not healed, 92.9% experienced improvement, and its healing curves were statistically significant (p < 0.05). 92.2% of clinicians assessed treatment with these products as good or excellent. The use of the products used in this study consistent with the concept and PLH TIME, has proved useful in this type of injury reducing the clinical signs of infection, promoting granulation tissue and necrotic removing the burden

  13. Physical, chemical and biological studies of gelatin/chitosan based transdermal fims with embedded silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Sneha Paul

    2015-12-01

    Full Text Available Objective: To study the physical, chemical and biological properties of composite chitosangelatin transdermal film along with silver nanoparticles as binding agent and determine the compatibility of the prepared amalgamation towards wound management. Methods: Transdermal film preparations were done by solvent casting method containing different concentrations of biological synthesized silver nanoparticles. The films were characterized by using scanning electron microscope for their morphology and the determination of silver metal was done by using inductively coupled plasma atomic emission spectroscopy. Then a quantity of silver nanoparticles was further proceeded by physiochemical parameters (weight, thickness, temperature, solubility, absorption, tensile strength, in vitro drug release and skin permeation and biological parameters studies (anti-microbial, cytotoxicity and reactive oxygen species. Results: The film prepared by utilizing 2 g of gelatin and 0.5 g of chitosan exhibited better results. The physiochemical parameters studies revealed higher concentration of silver nanoparticles would give better results. In vitro drug release studies through dialysis and skin permeation showed the release of drug versus time (h. These films had shown excellent inhibition against Streptococcus and Escherichia coli species. Cytotoxicity study by MTT indicated the mild toxicity existed as the concentration of silver nanoparticles increased. Reactive oxygen species generation studies of transdermal film by using 2'7'-dichlorofluorescein diacetate assay demonstrated that the fluorescent cells were found in the higher concentration, which indicated cell damage (reactive oxygen species generated. Conclusions: Based on these observations, in vitro performances against various characteristics of transdermal film, would be utilized as a distinct dressing material and patches accessible in market.

  14. Mechanical, electrical, and thermal expansion properties of carbon nanotube-based silver and silver-palladium alloy composites

    Science.gov (United States)

    Pal, Hemant; Sharma, Vimal

    2014-11-01

    The mechanical, electrical, and thermal expansion properties of carbon nanotube (CNT)-based silver and silver-palladium (10:1, w/w) alloy nanocomposites are reported. To tailor the properties of silver, CNTs were incorporated into a silver matrix by a modified molecular level-mixing process. CNTs interact weakly with silver because of their non-reactive nature and lack of mutual solubility. Therefore, palladium was utilized as an alloying element to improve interfacial adhesion. Comparative microstructural characterizations and property evaluations of the nanocomposites were performed. The structural characterizations revealed that decorated type-CNTs were dispersed, embedded, and anchored into the silver matrix. The experimental results indicated that the modification of the silver and silver-palladium nanocomposite with CNT resulted in increases in the hardness and Young's modulus along with concomitant decreases in the electrical conductivity and the coefficient of thermal expansion (CTE). The hardness and Young's modulus of the nanocomposites were increased by 30%-40% whereas the CTE was decreased to 50%-60% of the CTE of silver. The significantly improved CTE and the mechanical properties of the CNT-reinforced silver and silver-palladium nanocomposites are correlated with the intriguing properties of CNTs and with good interfacial adhesion between the CNTs and silver as a result of the fabrication process and the contact action of palladium as an alloying element.

  15. Qualitative bacteriology in malignant wounds--a prospective, randomized, clinical study to compare the effect of honey and silver dressings

    DEFF Research Database (Denmark)

    Lund-Nielsen, Betina; Adamsen, Lis; Gottrup, Finn

    2011-01-01

    . A prospective, randomized, single-blind controlled clinical study was conducted to evaluate the bacteriology of malignant wounds and compare the effect of a honey-coated (Group A) to a silver-coated (Group B) dressing on the qualitative bacteriology of malignant wounds. All wound interventions were performed...... years, range 47-92) consented to participate and completed the 4-week study. The majority were women (88%) with breast cancer (79%). No statistically significant differences were found between the type and number of different wound pathogens in the wounds during the course of the study or between Group...... were identified. Sixty-one percent (61%) of wounds decreased in size following treatment, but no significant differences were observed between the type and variety of wound pathogens and whether wound size decreased. Although quantitative bacteriological changes may have occurred, the possible...

  16. Novel protease-based diagnostic devices for detection of wound infection

    NARCIS (Netherlands)

    Heinzle, A.; Papen-Botterhuis, N.E.; Schiffer, D.; Schneider, K.P.; Binder, B.; Schintler, M.; Haaksman, I.K.; Lenting, H.B.; Gübitz, G.M.; Sigl, E.

    2013-01-01

    A gelatinase-based device for fast detection of wound infection was developed. Collective gelatinolytic activity in infected wounds was 23 times higher (p ≤ 0.001) than in noninfected wounds and blisters according to the clinical and microbiological description of the wounds. Enzyme activities of

  17. Chitosan based metallic nanocomposite scaffolds as antimicrobial wound dressings.

    Science.gov (United States)

    Mohandas, Annapoorna; Deepthi, S; Biswas, Raja; Jayakumar, R

    2018-09-01

    Chitosan based nanocomposite scaffolds have attracted wider applications in medicine, in the area of drug delivery, tissue engineering and wound healing. Chitosan matrix incorporated with nanometallic components has immense potential in the area of wound dressings due to its antimicrobial properties. This review focuses on the different combinations of Chitosan metal nanocomposites such as Chitosan/nAg, Chitosan/nAu, Chitosan/nCu, Chitosan/nZnO and Chitosan/nTiO 2 towards enhancement of healing or infection control with special reference to the antimicrobial mechanism of action and toxicity.

  18. Reinforcement of Conducting Silver-based Materials

    Directory of Open Access Journals (Sweden)

    Heike JUNG

    2014-09-01

    Full Text Available Silver is a well-known material in the field of contact materials because of its high electrical and thermal conductivity. However, due to its bad mechanical and switching properties, silver alloys or reinforcements of the ductile silver matrix are required. Different reinforcements, e. g. tungsten, tungsten carbide, nickel, cadmium oxide or tin oxide, are used in different sectors of switches. To reach an optimal distribution of these reinforcements, various manufacturing techniques (e. g. powder blending, preform infiltration, wet-chemical methods, internal oxidation are being used for the production of these contact materials. Each of these manufacturing routes offers different advantages and disadvantages. The mechanical alloying process displays a successful and efficient method to produce particle-reinforced metal-matrix composite powders. This contribution presents the obtained fine disperse microstructure of tungsten-particle-reinforced silver composite powders produced by the mechanical alloying process and displays this technique as possible route to provide feedstock powders for subsequent consolidation processes. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.4889

  19. Porous CS based membranes with improved antimicrobial properties for the treatment of infected wound in veterinary applications

    International Nuclear Information System (INIS)

    Tonda-Turo, C.; Ruini, F.; Argentati, M.; Di Girolamo, N.; Robino, P.; Nebbia, P.; Ciardelli, G.

    2016-01-01

    Recently, much attention has been given to the use of innovative solution for the treatment of infected wounds in animals. Current applied treatments are often un-effective leading to infection propagation and animal death. Novel engineered membranes based on chitosan (CS) can be prepared to combine local antimicrobial effect, high flexibility and easy manipulation. In this work, CS crosslinked porous membranes with improved antimicrobial properties were prepared via freeze-drying technique to promote wound healing and to reduce the bacterial proliferation in infected injuries. Silver nanoparticles (AgNPs) and gentamicin sulfate (GS) were incorporated into the CS matrices to impart antibacterial properties on a wild range of strains. CS based porous membranes were tested for their physicochemical, thermal, mechanical as well as swelling and degradation behavior at physiological condition. Additionally, GS release profile was investigated, showing a moderate burst effect in the first days followed by a decreasing release rate which it was maintained for at least 56 days. Moreover, porous membranes loaded with GS or AgNPs showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria. The bacterial strains used in this work were collected in chelonians after carapace injuries to better mimic the environment after trauma. - Highlights: • Innovative scaffolds for wound healing in veterinary applications • Novel engineered membranes based on chitosan with improved antibacterial properties • Highly flexible and versatile membranes for infected wounds

  20. Porous CS based membranes with improved antimicrobial properties for the treatment of infected wound in veterinary applications

    Energy Technology Data Exchange (ETDEWEB)

    Tonda-Turo, C., E-mail: chiara.tondaturo@polito.it [Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin (Italy); Ruini, F. [Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin (Italy); Argentati, M. [Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin (Italy); Clinic for Exotic Animals, CVS, Via Sandro Giovannini 53, 00137 Rome (Italy); Di Girolamo, N. [Clinic for Exotic Animals, CVS, Via Sandro Giovannini 53, 00137 Rome (Italy); Robino, P.; Nebbia, P. [Department of Veterinary Sciences, University of Turin, Largo Braccini 2, 10095 Grugliasco, Turin (Italy); Ciardelli, G. [Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Turin (Italy)

    2016-03-01

    Recently, much attention has been given to the use of innovative solution for the treatment of infected wounds in animals. Current applied treatments are often un-effective leading to infection propagation and animal death. Novel engineered membranes based on chitosan (CS) can be prepared to combine local antimicrobial effect, high flexibility and easy manipulation. In this work, CS crosslinked porous membranes with improved antimicrobial properties were prepared via freeze-drying technique to promote wound healing and to reduce the bacterial proliferation in infected injuries. Silver nanoparticles (AgNPs) and gentamicin sulfate (GS) were incorporated into the CS matrices to impart antibacterial properties on a wild range of strains. CS based porous membranes were tested for their physicochemical, thermal, mechanical as well as swelling and degradation behavior at physiological condition. Additionally, GS release profile was investigated, showing a moderate burst effect in the first days followed by a decreasing release rate which it was maintained for at least 56 days. Moreover, porous membranes loaded with GS or AgNPs showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria. The bacterial strains used in this work were collected in chelonians after carapace injuries to better mimic the environment after trauma. - Highlights: • Innovative scaffolds for wound healing in veterinary applications • Novel engineered membranes based on chitosan with improved antibacterial properties • Highly flexible and versatile membranes for infected wounds.

  1. Enhance wound healing monitoring through a thermal imaging based smartphone app

    Science.gov (United States)

    Yi, Steven; Lu, Minta; Yee, Adam; Harmon, John; Meng, Frank; Hinduja, Saurabh

    2018-03-01

    In this paper, we present a thermal imaging based app to augment traditional appearance based wound growth monitoring. Accurate diagnose and track of wound healing enables physicians to effectively assess, document, and individualize the treatment plan given to each wound patient. Currently, wounds are primarily examined by physicians through visual appearance and wound area. However, visual information alone cannot present a complete picture on a wound's condition. In this paper, we use a smartphone attached thermal imager and evaluate its effectiveness on augmenting visual appearance based wound diagnosis. Instead of only monitoring wound temperature changes on a wound, our app presents physicians a comprehensive measurements including relative temperature, wound healing thermal index, and wound blood flow. Through the rat wound experiments and by monitoring the integrated thermal measurements over 3 weeks of time frame, our app is able to show the underlying healing process through the blood flow. The implied significance of our app design and experiment includes: (a) It is possible to use a low cost smartphone attached thermal imager for added value on wound assessment, tracking, and treatment; and (b) Thermal mobile app can be used for remote wound healing assessment for mobile health based solution.

  2. Electrospun poly(ε-caprolactone) matrices containing silver sulfadiazine complexed with β-cyclodextrin as a new pharmaceutical dosage form to wound healing: preliminary physicochemical and biological evaluation.

    Science.gov (United States)

    Souza, Sarah Oliveira Lamas; Cotrim, Monique Alvarenga Pinto; Oréfice, Rodrigo Lambert; Carvalho, Suzana Gonçalves; Dutra, Jessyca Aparecida Paes; de Paula Careta, Francisco; Resende, Juliana Alves; Villanova, Janaina Cecília Oliveira

    2018-05-10

    Cooperation between researchers in the areas of medical, pharmaceutical and materials science has facilitated the development of pharmaceutical dosage forms that elicit therapeutic effects and protective action with a single product. In addition to optimizing pharmacologic action, such dosage forms provide greater patient comfort and increase success and treatment compliance. In the present work, we prepared semipermeable bioactive electrospun fibers for use as wound dressings containing silver sulfadiazine complexed with β-cyclodextrin in a poly(Ɛ-caprolactone) nanofiber matrix aiming to reduce the direct contact between silver and skin and to modulate the drug release. Wound dressings were prepared by electrospinning, and were subjected to ATR-FT-IR and TG/DTG assays to evaluate drug stability. The hydrophilicity of the fibrous nanostructure in water and PBS buffer was studied by goniometry. Electrospun fibers permeability and swelling capacity were assessed, and a dissolution test was performed. In vitro biological tests were realized to investigate the biological compatibility and antimicrobial activity. We obtained flexible matrices that were each approximately 1.0 g in weight. The electrospun fibers were shown to be semipermeable, with water vapor transmission and swelling indexes compatible with the proposed objective. The hydrophilicity was moderate. Matrices containing pure drug modulated drug release adequately during 24 h but presented a high hemolytic index. Complexation promoted a decrease in the hemolytic index and in the drug release but did not negatively impact antimicrobial activity. The drug was released predominantly by diffusion. These results indicate that electrospun PCL matrices containing β-cyclodextrin/silver sulfadiazine inclusion complexes are a promising pharmaceutical dosage form for wound healing.

  3. A modern method of treatment: The role of silver dressings in promoting healing and preventing pathological scarring in patients with burn wounds

    Science.gov (United States)

    Munteanu, A; Florescu, IP; Nitescu, C

    2016-01-01

    Burn wounds are a global public health problem, which affects all countries, no matter the development stage and occurs in all age groups, from toddlers to elderly. In spite of burns being the cause of numerous household and work accidents, there are still no clear stated unanimous rules for their treatment. Every day new products appear on the market, each of them trying to prove more effective. Since ancient times, silver has been known for its antimicrobial properties, so it has been used for a long time in the treatment of burns and other types of wounds. One of the relatively modern methods of treatment is applying silver sheets on the scald lesions. In this paper, which was part of a larger study (research for a PhD thesis), concerning prevention and treatment of the post-burn pathological scars, the cases of some patients with burns, who were treated by using the above mentioned method were presented and analyzed. The results obtained by applying silver sheets were then commented and interpreted, pointing out the advantages and disadvantages compared to silver sulfadiazine creams and ointments, which have already been used at a large scale. The prevention and treatment of post-burn pathological (hypertrophic and keloid) scars is a field in which still little is known and in which there are also no clearly set therapy plans. We hope that through this research and the following ones we will manage to establish some major guidelines concerning the prevention of pathological scars, which are not only disabling, but also a major aesthetic issue for any patient, in order to obtain better outcomes. PMID:27974941

  4. Development of chitosan oleate ionic micelles loaded with silver sulfadiazine to be associated with platelet lysate for application in wound healing.

    Science.gov (United States)

    Dellera, Eleonora; Bonferoni, Maria Cristina; Sandri, Giuseppina; Rossi, Silvia; Ferrari, Franca; Del Fante, Claudia; Perotti, Cesare; Grisoli, Pietro; Caramella, Carla

    2014-11-01

    In the treatment of chronic wounds, topical application of anti-infective drugs such as silver sulfadiazine (AgSD) is of primary importance to avoid infections and accelerate wound repair. AgSD is used in burns and chronic wounds for its wide antibacterial spectrum, but presents limitations due to poor solubility and cytotoxicity. In the present work polymeric micelles obtained by self-assembling of chitosan ionically modified by interaction with oleic acid were developed as carriers for AgSD to overcome the drawbacks of the drug. The AgSD loaded micelles were intended to be associated in wound healing with platelet lysate (PL), a hemoderivative rich in growth factors. Unloaded micelles demonstrated good compatibility with both fibroblasts and PL. The relevance of chitosan concentration and of the ratio between chitosan and oleic acid to the drug loading and the particle size of nanoparticles was studied. A marked increase (up to 100 times with respect to saturated solution) of AgSD concentration in micelle dispersion was obtained. Moreover, the encapsulation reduced the cytotoxic effect of the drug towards fibroblasts and the drug incompatibility with PDGF-AB (platelet derived growth factor), chosen as representative of platelet growth factors. Copyright © 2014. Published by Elsevier B.V.

  5. Photonic Crystal Fibre SERS Sensors Based on Silver Nanoparticle Colloid

    International Nuclear Information System (INIS)

    Zhi-Guo, Xie; Yong-Hua, Lu; Pei, Wang; Kai-Qun, Lin; Jie, Yan; Hai, Ming

    2008-01-01

    A photonic crystal fibre (PCF) surface enhanced Raman scattering (SERS) sensor is developed based on silver nanoparticle colloid. Analyte solution and silver nanoparticles are injected into the air holes of PCF by a simple modified syringe to overcome mass-transport constraints, allowing more silver nanoparticles involved in SERS activity. This sensor offers significant benefit over the conventional SERS sensor with high flexibility, easy manufacture. We demonstrate the detection of 4-mercaptobenzoic acid (4-MBA) molecules with the injecting way and the common dipping measurement. The injecting way shows obviously better results than the dipping one. Theoretical analysis indicates that this PCF SERS substrate offers enhancement of about 7 orders of magnitude in SERS active area

  6. Biological evaluation of silver nanoparticles incorporated into chitosan-based membranes

    NARCIS (Netherlands)

    Shao, J.; Yu, N.; Kolwijck, E.; Wang, B.; Tan, K.W.; Jansen, J.A.; Walboomers, X.F.; Yang, F.

    2017-01-01

    AIM: To evaluate the antibacterial potential and biological performance of silver nanoparticles in chitosan-based membranes. MATERIALS & METHODS: Electrospun chitosan/poly(ethylene oxide) membranes with different amounts of silver nanoparticles were evaluated for antibacterial properties and

  7. Silk fibroin based antibacterial bionanotextiles as wound dressing materials

    Energy Technology Data Exchange (ETDEWEB)

    Çalamak, Semih [Hacettepe University, Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, 06100 Ankara (Turkey); Hacettepe University, Department of Nanotechnology and Nanomedicine, 06800 Ankara (Turkey); Erdoğdu, Ceren; Özalp, Meral [Hacettepe University, Faculty of Pharmacy, Department of Pharmaceutical Microbiology, 06100 Ankara (Turkey); Ulubayram, Kezban, E-mail: ukezban@hacettepe.edu.tr [Hacettepe University, Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, 06100 Ankara (Turkey); Hacettepe University, Department of Nanotechnology and Nanomedicine, 06800 Ankara (Turkey)

    2014-10-01

    New applications for medical biotextiles have been identified with the development of nanotechnological manufacturing technologies. Combination of nanotechnology and biotextile technology has resulted into a new field called bionanotextiles. Bionanotextiles are used in many areas which include wound dressings, bandages and tissue scaffolds. Silk fibroin (SF) from the cocoon of Bombyx mori, is one of the most favorable wound dressing materials due to its unique properties including biocompatibility, permeability, biodegradability, morphologic flexibility, and proper mechanical properties. The modification of antimicrobial properties of SFs can provide a barrier for bacterial penetration as wound dressing materials. In the present study, antibacterial polyethylenimine (PEI) (10, 20 and 30% (w/w)) was blended with SF and bionanotextiles were successfully fabricated by electrospinning. In addition, silk fibroin nanofibers were also functionalized with sulphate group in order to test whether they exhibit an antibacterial activity or not. Fibroin based bionanotextiles were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The cytotoxicity evaluations were carried out by L929 fibroblasts with MTT assay. The indirect cytotoxicity results demonstrate that all fibroin and PEI/fibroin extracts have no cytotoxicity on L929 cancer cell line. PEI/fibroin bionanotextiles showed strong antibacterial activities against gram positive Staphylococcus aureus and gram negative Pseudomonas aeruginosa. - Highlights: • Bionanotextiles are combination of nanotechnology and biotextile technology. • Bionanotextiles have good antibacterial activity against both of S. aureus and P. aeruginosa. • Antibacterial bionanotextiles are applicable to most of the infected wounds. • No cytotoxicity was observed on L929 cell line.

  8. Silk fibroin based antibacterial bionanotextiles as wound dressing materials

    International Nuclear Information System (INIS)

    Çalamak, Semih; Erdoğdu, Ceren; Özalp, Meral; Ulubayram, Kezban

    2014-01-01

    New applications for medical biotextiles have been identified with the development of nanotechnological manufacturing technologies. Combination of nanotechnology and biotextile technology has resulted into a new field called bionanotextiles. Bionanotextiles are used in many areas which include wound dressings, bandages and tissue scaffolds. Silk fibroin (SF) from the cocoon of Bombyx mori, is one of the most favorable wound dressing materials due to its unique properties including biocompatibility, permeability, biodegradability, morphologic flexibility, and proper mechanical properties. The modification of antimicrobial properties of SFs can provide a barrier for bacterial penetration as wound dressing materials. In the present study, antibacterial polyethylenimine (PEI) (10, 20 and 30% (w/w)) was blended with SF and bionanotextiles were successfully fabricated by electrospinning. In addition, silk fibroin nanofibers were also functionalized with sulphate group in order to test whether they exhibit an antibacterial activity or not. Fibroin based bionanotextiles were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The cytotoxicity evaluations were carried out by L929 fibroblasts with MTT assay. The indirect cytotoxicity results demonstrate that all fibroin and PEI/fibroin extracts have no cytotoxicity on L929 cancer cell line. PEI/fibroin bionanotextiles showed strong antibacterial activities against gram positive Staphylococcus aureus and gram negative Pseudomonas aeruginosa. - Highlights: • Bionanotextiles are combination of nanotechnology and biotextile technology. • Bionanotextiles have good antibacterial activity against both of S. aureus and P. aeruginosa. • Antibacterial bionanotextiles are applicable to most of the infected wounds. • No cytotoxicity was observed on L929 cell line

  9. Silver oxide nanoparticles embedded silk fibroin spuns: Microwave mediated preparation, characterization and their synergistic wound healing and anti-bacterial activity.

    Science.gov (United States)

    Babu, Punuri Jayasekhar; Doble, Mukesh; Raichur, Ashok M

    2018-03-01

    The synergistic wound healing and antibacterial activity of silver oxide nanoparticles embedded silk fibroin (Ag 2 O-SF) spuns is reported here. UV-Vis spectro photometric analysis of these spuns showed the surface plasmon resonance (SPR) confirming the formation of the silver oxide nanoparticles (Ag 2 O NPs) on the surface of the silk fibroin (SF). Scanning electron microscope (SEM) and Differential scanning calorimetry (DSC) also confirmed the presence of Ag 2 O NPs on surface of SF. X-ray diffraction (XRD) analysis revealed the crystalline nature of both SF and Ag 2 O-SF. Fourier transform infrared spectroscopy (FT-IR) results showed the different forms of silk (I and II) and their corresponding protein (amide I, II, III) confirmations. Biodegradation study revealed insignificant changes in the morphology of Ag 2 O-SF spuns even after 14 days of immersion in phosphate buffered saline (PBS). Ag 2 O-SF spuns showed excellent antibacterial activity against both pathogen (S. aureus and M. tuberculosis) and non-pathogen (E. coli) bacteria. More importantly, In vitro wound healing (scratch assay) assay revealed fast migration of the T3T fibroblast cells through the scratch area treated with extract of Ag 2 O-SF spuns and the area was completely covered within 24 h. Cytotoxicity assay confirmed the biocompatible nature of the Ag 2 O-SF spuns, thus suggesting an ideal material for wound healing and anti-bacterial applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Elements affecting wound healing time: An evidence based analysis.

    Science.gov (United States)

    Khalil, Hanan; Cullen, Marianne; Chambers, Helen; Carroll, Matthew; Walker, Judi

    2015-01-01

    The purpose of this study was to identify the predominant client factors and comorbidities that affected the time taken for wounds to heal. A prospective study design used the Mobile Wound Care (MWC) database to capture and collate detailed medical histories, comorbidities, healing times and consumable costs for clients with wounds in Gippsland, Victoria. There were 3,726 wounds documented from 2,350 clients, so an average of 1.6 wounds per client. Half (49.6%) of all clients were females, indicating that there were no gender differences in terms of wound prevalence. The clients were primarily older people, with an average age of 64.3 years (ranging between 0.7 and 102.9 years). The majority of the wounds (56%) were acute and described as surgical, crush and trauma. The MWC database categorized the elements that influenced wound healing into 3 groups--factors affecting healing (FAH), comorbidities, and medications known to affect wound healing. While there were a multitude of significant associations, multiple linear regression identified the following key elements: age over 65 years, obesity, nonadherence to treatment plan, peripheral vascular disease, specific wounds associated with pressure/friction/shear, confirmed infection, and cerebrovascular accident (stroke). Wound healing is a complex process that requires a thorough understanding of influencing elements to improve healing times.© 2015 by the Wound Healing Society. © 2015 by the Wound Healing Society.

  11. Effect of discarded keratin-based biocomposite hydrogels on the wound healing process in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Park, Mira [Department of Organic Materials & Fiber Engineering, Chonbuk National University, Jeonju 561–756 (Korea, Republic of); Shin, Hye Kyoung [Department of Chemistry, Inha University, 100 Inharo, Incheon 402–751 (Korea, Republic of); Kim, Byoung-Suhk [Department of BIN fusion technology, Chonbuk National University, Jeonju 561–756 (Korea, Republic of); Kim, Myung Jin; Kim, In-Shik [Department of Veterinary Anatomy, College of Veterinary Medicine and Bio-safety Research institute, Chonbuk National University, Jeonju 561–756 (Korea, Republic of); Park, Byung-Yong, E-mail: parkb@jbnu.ac.kr [Department of Veterinary Anatomy, College of Veterinary Medicine and Bio-safety Research institute, Chonbuk National University, Jeonju 561–756 (Korea, Republic of); Kim, Hak-Yong, E-mail: khy@jbnu.ac.kr [Department of BIN fusion technology, Chonbuk National University, Jeonju 561–756 (Korea, Republic of)

    2015-10-01

    Biocompatible keratin-based hydrogels prepared by electron beam irradiation (EBI) were examined in wound healing. As the EBI dose increased to 60 kGy, the tensile strength of the hydrogels increased, while the percentage of elongation of the hydrogels decreased. After 7 days, the dehydrated wool-based hydrogels show the highest mechanical properties (the % elongation of 1341 and the tensile strength of 6030 g/cm{sup 2} at an EBI dose of 30 kGy). Excision wound models were used to evaluate the effects of human hair-based hydrogels and wool-based hydrogels on various phases of healing. On post-wounding days 7 and 14, wounds treated with either human hair-based or wool-based hydrogels were greatly reduced in size compared to wounds that received other treatments, although the hydrocolloid wound dressing-treated wound also showed a pronounced reduction in size compared to an open wound as measured by a histological assay. On the 14th postoperative day, the cellular appearances were similar in the hydrocolloid wound dressing and wool-based hydrogel-treated wounds, and collagen fibers were substituted with fibroblasts and mixed with fibroblasts in the dermis. Furthermore, the wound treated with a human hair-based hydrogel showed almost complete epithelial regeneration, with the maturation of immature connective tissue and hair follicles and formation of a sebaceous gland. - Highlights: • Biocompatible keratin-based hydrogels were examined for wound healing process. • Human hair-based hydrogel is superior to wool-based hydrogel in wound healing. • Discarded keratin-based hydrogels are expected more eco-friendly therapeutic agents.

  12. Composite Scaffolds Based on Silver Nanoparticles for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Jenel Marian Patrascu

    2015-01-01

    Full Text Available This paper presents the synthesis, characterisation, and in vitro testing of homogenous and heterogeneous materials containing silver nanoparticles (nanoAg. Three types of antiseptic materials based on collagen (COLL, hydroxyapatite (HA, and collagen/hydroxyapatite (COLL/HA composite materials were obtained. The synthesis of silver nanoparticles was realized by chemical reaction as well as plasma sputtering deposition. The use of chemical reduction allows the synthesis of homogenous materials while the plasma sputtering deposition can be easily used for the synthesis of homogeneous and heterogeneous support. Based on the in vitro assays clear antiseptic activity against Escherichia coli was relieved even at low content of nanoAg (10 ppm.

  13. Electrical studies on silver based fast ion conducting glassy materials

    International Nuclear Information System (INIS)

    Rao, B. Appa; Kumar, E. Ramesh; Kumari, K. Rajani; Bhikshamaiah, G.

    2014-01-01

    Among all the available fast ion conductors, silver based glasses exhibit high conductivity. Further, glasses containing silver iodide enhances fast ion conducting behavior at room temperature. Glasses of various compositions of silver based fast ion conductors in the AgI−Ag 2 O−[(1−x)B 2 O 3 −xTeO 2 ] (x=0 to1 mol% in steps of 0.2) glassy system have been prepared by melt quenching method. The glassy nature of the compounds has been confirmed by X-ray diffraction. The electrical conductivity (AC) measurements have been carried out in the frequency range of 1 KHz–3MHz by Impedance Analyzer in the temperature range 303–423K. The DC conductivity measurements were also carried out in the temperature range 300–523K. From both AC and DC conductivity studies, it is found that the conductivity increases and activation energy decreases with increasing the concentration of TeO 2 as well as with temperature. The conductivity of the present glass system is found to be of the order of 10 −2 S/cm at room temperature. The ionic transport number of these glasses is found to be 0.999 indicating that these glasses can be used as electrolyte in batteries

  14. Phyto-assisted synthesis of bio-functionalised silver nanoparticles and their potential anti-oxidant, anti-microbial and wound healing activities.

    Science.gov (United States)

    Mohanta, Yugal Kishore; Biswas, Kunal; Panda, Sujogya Kumar; Bandyopadhyay, Jaya; De, Debashis; Jayabalan, Rasu; Bastia, Akshaya Kumar; Mohanta, Tapan Kumar

    2017-12-01

    Bio- synthesis of silver nanoparticles (AgNPs) was made by using the aqueous leaf extract of Ardisia solanacea. Rapid formation of AgNPs was observed from silver nitrate upon treatment with the aqueous extract of A. solanacea leaf. The formation and stability of the AgNPs in the colloidal solution were monitored by UV-visible spectrophotometer. The mean particle diameter of AgNPs was calculated from the DLS with an average size ∼4 nm and ∼65 nm. ATR-FTIR spectroscopy confirmed the presence of alcohols, aldehydes, flavonoids, phenols and nitro compounds in the leaf which act as the stabilizing agent. Antimicrobial activity of the synthesized AgNPs was performed using agar well diffusion and broth dilution method against the Gram-positive and Gram-negative bacteria. Further, robust anti-oxidative potential was evaluated by DPPH assay. The highest antimicrobial activity of synthesized AgNPs was found against Pseudomonas aeruginosa (28.2 ± 0.52 mm) whereas moderate activity was found against Bacillus subtilis (16.1 ± 0.76), Candida kruseii (13.0 ± 1.0), and Trichophyton mentagrophytes (12.6 ± 1.52). Moreover, the potential wound healing activity was observed against the BJ-5Ta normal fibroblast cell line. Current research revealed that A. solanacea was found to be a suitable source for the green synthesis of silver nanoparticles.

  15. Wound healing activity of Sida cordifolia Linn. in rats.

    Science.gov (United States)

    Pawar, Rajesh S; Chaurasiya, Pradeep K; Rajak, Harish; Singour, Pradeep K; Toppo, Fedelic Ashish; Jain, Ankit

    2013-01-01

    The present study provides a scientific evaluation for the wound healing potential of ethanolic (EtOH) extract of Sida cordifolia Linn. (SCL) plant. Excision, incision and burn wounds were inflicted upon three groups of six rats each. Group I was assigned as control (ointment base). Group II was treated with 10% EtOH extract ointment. Group III was treated with standard silver sulfadiazine (0.01%) cream. The parameters observed were percentage of wound contraction, epithelialization period, hydroxyproline content, tensile strength including histopathological studies. It was noted that the effect produced by the ethanolic extract of SCL ointment showed significant (P < 0.01) healing in all wound models when compared with the control group. All parameters such as wound contraction, epithelialization period, hydroxyproline content, tensile strength and histopathological studies showed significant (P < 0.01) changes when compared with the control. The ethanolic extract ointment of SCL effectively stimulates wound contraction; increases tensile strength of excision, incision and burn wounds.

  16. Silver against Pseudomonas aeruginosa biofilms

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Kirketerp-Møller, K.; Kristiansen, S.

    2007-01-01

    bacteria in both the planktonic and biofilm modes of growth. The action of silver on mature in vitro biofilms of Pseudomonas aeruginosa, a primary pathogen of chronic infected wounds, was investigated. The results show that silver is very effective against mature biofilms of P. aeruginosa......, but that the silver concentration is important. A concentration of 5-10 ig/mL silver sulfadiazine eradicated the biofilm whereas a lower concentration (1 ig/mL) had no effect. The bactericidal concentration of silver required to eradicate the bacterial biofilm was 10-100 times higher than that used to eradicate...... planktonic bacteria. These observations strongly indicate that the concentration of silver in currently available wound dressings is much too low for treatment of chronic biofilm wounds. It is suggested that clinicians and manufacturers of the said wound dressings consider whether they are treating wounds...

  17. An Automatic Assessment System of Diabetic Foot Ulcers Based on Wound Area Determination, Color Segmentation, and Healing Score Evaluation.

    Science.gov (United States)

    Wang, Lei; Pedersen, Peder C; Strong, Diane M; Tulu, Bengisu; Agu, Emmanuel; Ignotz, Ron; He, Qian

    2015-08-07

    For individuals with type 2 diabetes, foot ulcers represent a significant health issue. The aim of this study is to design and evaluate a wound assessment system to help wound clinics assess patients with foot ulcers in a way that complements their current visual examination and manual measurements of their foot ulcers. The physical components of the system consist of an image capture box, a smartphone for wound image capture and a laptop for analyzing the wound image. The wound image assessment algorithms calculate the overall wound area, color segmented wound areas, and a healing score, to provide a quantitative assessment of the wound healing status both for a single wound image and comparisons of subsequent images to an initial wound image. The system was evaluated by assessing foot ulcers for 12 patients in the Wound Clinic at University of Massachusetts Medical School. As performance measures, the Matthews correlation coefficient (MCC) value for the wound area determination algorithm tested on 32 foot ulcer images was .68. The clinical validity of our healing score algorithm relative to the experienced clinicians was measured by Krippendorff's alpha coefficient (KAC) and ranged from .42 to .81. Our system provides a promising real-time method for wound assessment based on image analysis. Clinical comparisons indicate that the optimized mean-shift-based algorithm is well suited for wound area determination. Clinical evaluation of our healing score algorithm shows its potential to provide clinicians with a quantitative method for evaluating wound healing status. © 2015 Diabetes Technology Society.

  18. A Composite Model of Wound Segmentation Based on Traditional Methods and Deep Neural Networks

    Directory of Open Access Journals (Sweden)

    Fangzhao Li

    2018-01-01

    Full Text Available Wound segmentation plays an important supporting role in the wound observation and wound healing. Current methods of image segmentation include those based on traditional process of image and those based on deep neural networks. The traditional methods use the artificial image features to complete the task without large amounts of labeled data. Meanwhile, the methods based on deep neural networks can extract the image features effectively without the artificial design, but lots of training data are required. Combined with the advantages of them, this paper presents a composite model of wound segmentation. The model uses the skin with wound detection algorithm we designed in the paper to highlight image features. Then, the preprocessed images are segmented by deep neural networks. And semantic corrections are applied to the segmentation results at last. The model shows a good performance in our experiment.

  19. Combination of silver nanoparticles and Drosera binata extract as a possible alternative for antibiotic treatment of burn wound infections caused by resistant Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Marta Krychowiak

    Full Text Available Staphylococcus aureus is the most common infectious agent involved in the development of skin infections that are associated with antibiotic resistance, such as burn wounds. As drug resistance is a growing problem it is essential to establish novel antimicrobials. Currently, antibiotic resistance in bacteria is successfully controlled by multi-drug therapies. Here we demonstrate that secondary metabolites present in the extract obtained from Drosera binata in vitro cultures are effective antibacterial agents against S. aureus grown in planktonic culture and in biofilm. Moreover, this is the first report demonstrating the synergistic interaction between the D. binata extract and silver nanoparticles (AgNPs, which results in the spectacular enhancement of the observed bactericidal activity, while having no cytotoxic effects on human keratinocytes. Simultaneous use of these two agents in significantly reduced quantities produces the same effect, i.e. by killing 99.9% of bacteria in inoculum or eradicating the staphylococcal biofilm, as higher amounts of the agents used individually. Our data indicates that combining AgNPs with either the D. binata extract or with its pure compound (3-chloroplumbagin may provide a safe and highly effective alternative to commonly used antibiotics, which are ineffective towards the antibiotic-resistant S. aureus.

  20. Combination of silver nanoparticles and Drosera binata extract as a possible alternative for antibiotic treatment of burn wound infections caused by resistant Staphylococcus aureus.

    Science.gov (United States)

    Krychowiak, Marta; Grinholc, Mariusz; Banasiuk, Rafal; Krauze-Baranowska, Miroslawa; Głód, Daniel; Kawiak, Anna; Królicka, Aleksandra

    2014-01-01

    Staphylococcus aureus is the most common infectious agent involved in the development of skin infections that are associated with antibiotic resistance, such as burn wounds. As drug resistance is a growing problem it is essential to establish novel antimicrobials. Currently, antibiotic resistance in bacteria is successfully controlled by multi-drug therapies. Here we demonstrate that secondary metabolites present in the extract obtained from Drosera binata in vitro cultures are effective antibacterial agents against S. aureus grown in planktonic culture and in biofilm. Moreover, this is the first report demonstrating the synergistic interaction between the D. binata extract and silver nanoparticles (AgNPs), which results in the spectacular enhancement of the observed bactericidal activity, while having no cytotoxic effects on human keratinocytes. Simultaneous use of these two agents in significantly reduced quantities produces the same effect, i.e. by killing 99.9% of bacteria in inoculum or eradicating the staphylococcal biofilm, as higher amounts of the agents used individually. Our data indicates that combining AgNPs with either the D. binata extract or with its pure compound (3-chloroplumbagin) may provide a safe and highly effective alternative to commonly used antibiotics, which are ineffective towards the antibiotic-resistant S. aureus.

  1. Nanotechnology-Based Therapies for Skin Wound Regeneration

    International Nuclear Information System (INIS)

    Tocco, I.; Bassetto, F.; Vindigni, V.; Zavan, B.

    2012-01-01

    The cutting-edge combination of nano technology with medicine offers the unprecedented opportunity to create materials and devices at a nano scale level, holding the potential to revolutionize currently available macro scale therapeutics. Nano technology already provides a plethora of advantages to medical care, and the success of nano particulate systems suggests that a progressive increase in the exploration of their potential will take place in the near future. An overview on the current applications of nano technology to wound healing and wound care is presented

  2. Transmission electron microscopy for elucidating the impact of silver-based treatments (ionic silver versus nanosilver-containing coating) on the model yeast Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Despax, B; Saulou, C; Raynaud, P [Universite de Toulouse, UPS, INPT, LAPLACE, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Datas, L [Universite de Toulouse, UPS, INPT, CIRIMAT, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Mercier-Bonin, M [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France)

    2011-04-29

    After exposure to ionic silver or nanosilver-containing plasma coating, the same visual aspect of scanning transmission electron microscopy (STEM) images was observed for the model yeast Saccharomyces cerevisiae. The main common feature was the presence of electron-dense nodules all over the cell. However, high resolution TEM (HRTEM), STEM, energy dispersive x-ray microanalysis spectroscopy (EDS) and electron microdiffraction revealed some striking differences. Regarding ionic silver exposure, the formation of electron-dense nodules was related to the Ag{sup +} reactivity towards sulfur-containing compounds to form clusters with Ag{sub 2}S-like structures, together with the production of a few silver nanocrystals, mainly at the cell wall periphery. For nanosilver-based treatment, some sulfur-containing silver clusters preferentially located at the cell wall periphery were detected, together with nodules composed of silver, sulfur and phosphorus all over the cell. In both silver-based treatments, nitrogen and silver signals overlapped, confirming the affinity of silver entities for proteinaceous compounds. Moreover, in the case of nanosilver, interactions of silver with phosphorus-containing subcellular structures were indicated.

  3. Wound Healing Activity of Topical Application Forms Based on Ayurveda

    Directory of Open Access Journals (Sweden)

    Hema Sharma Datta

    2011-01-01

    Full Text Available The traditional Indian medicine—Ayurveda, describes various herbs, fats, oils and minerals with anti-aging as well as wound healing properties. With aging, numerous changes occur in skin, including decrease in tissue cell regeneration, decrease in collagen content, loss of skin elasticity and mechanical strength. We prepared five topical anti-aging formulations using cow ghee, flax seed oil, Phyllanthus emblica fruits, Shorea robusta resin, Yashada bhasma as study materials. For preliminary efficacy evaluation of the anti-aging activity we chose excision and incision wound healing animal models and studied the parameters including wound contraction, collagen content and skin breaking strength which in turn is indicative of the tissue cell regeneration capacity, collagenation capacity and mechanical strength of skin. The group treated with the formulations containing Yashada bhasma along with Shorea robusta resin and flax seed oil showed significantly better wound contraction (P < .01, higher collagen content (P < .05 and better skin breaking strength (P < .01 as compared to control group; thus proposing them to be effective prospective anti-aging formulations.

  4. Community analysis of chronic wound bacteria using 16S rRNA gene-based pyrosequencing: impact of diabetes and antibiotics on chronic wound microbiota.

    Directory of Open Access Journals (Sweden)

    Lance B Price

    Full Text Available BACKGROUND: Bacterial colonization is hypothesized to play a pathogenic role in the non-healing state of chronic wounds. We characterized wound bacteria from a cohort of chronic wound patients using a 16S rRNA gene-based pyrosequencing approach and assessed the impact of diabetes and antibiotics on chronic wound microbiota. METHODOLOGY/PRINCIPAL FINDINGS: We prospectively enrolled 24 patients at a referral wound center in Baltimore, MD; sampled patients' wounds by curette; cultured samples under aerobic and anaerobic conditions; and pyrosequenced the 16S rRNA V3 hypervariable region. The 16S rRNA gene-based analyses revealed an average of 10 different bacterial families in wounds--approximately 4 times more than estimated by culture-based analyses. Fastidious anaerobic bacteria belonging to the Clostridiales family XI were among the most prevalent bacteria identified exclusively by 16S rRNA gene-based analyses. Community-scale analyses showed that wound microbiota from antibiotic treated patients were significantly different from untreated patients (p = 0.007 and were characterized by increased Pseudomonadaceae abundance. These analyses also revealed that antibiotic use was associated with decreased Streptococcaceae among diabetics and that Streptococcaceae was more abundant among diabetics as compared to non-diabetics. CONCLUSIONS/SIGNIFICANCE: The 16S rRNA gene-based analyses revealed complex bacterial communities including anaerobic bacteria that may play causative roles in the non-healing state of some chronic wounds. Our data suggest that antimicrobial therapy alters community structure--reducing some bacteria while selecting for others.

  5. The evidence-based principles of negative pressure wound therapy in trauma & orthopedics.

    Science.gov (United States)

    A, Novak; Khan, Wasim S; J, Palmer

    2014-01-01

    Negative pressure wound therapy is a popular treatment for the management of both acute and chronic wounds. Its use in trauma and orthopedics is diverse and includes the acute traumatic setting as well as chronic troublesome wounds associated with pressure sores and diabetic foot surgery. Efforts have been made to provide an evidence base to guide its use however this has been limited by a lack of good quality evidence. The following review article explores the available evidence and describes future developments for its use in trauma and orthopaedic practice.

  6. A new silver based composite material for SPA water disinfection.

    Science.gov (United States)

    Tartanson, M A; Soussan, L; Rivallin, M; Chis, C; Penaranda, D; Lapergue, R; Calmels, P; Faur, C

    2014-10-15

    A new composite material based on alumina (Al2O3) modified by two surface nanocoatings - titanium dioxide (TiO2) and silver (Ag) - was studied for spa water disinfection. Regarding the most common microorganisms in bathing waters, two non-pathogenic bacteria Escherichia coli (Gram-negative) and Staphylococcus epidermidis (Gram positive) were selected as surrogates for bacterial contamination. The bactericidal properties of the Al2O3-TiO2-Ag material were demonstrated under various operating conditions encountered in spa water (temperature: 22-37 °C, presence of salt: CaCO3 or CaCl2, high oxygen content, etc.). Total removal of 10(8) CFU mL(-1) of bacteria was obtained in less than 10 min with 16 g L(-1) of material. Best results were observed for both conditions: a temperature of 37 °C and under aerobic condition; this latest favouring Reactive Oxygen Species (ROS) generation. The CaCO3 salt had no impact on the bactericidal activity of the composite material and CaCl2 considerably stabilized the silver desorption from the material surface thanks to the formation of AgCl precipitate. Preliminary tests of the Al2O3-TiO2-Ag bactericidal behaviour in a continuous water flow confirmed that 2 g L(-1) of material eliminated more than 90% of a 2.0 × 10(8) CFU mL(-1) bacterial mixture after one water treatment recycle and reached the disinfection standard recommended by EPA (coliform removal = 6 log) within 22 h. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. PLGA based drug delivery systems: Promising carriers for wound healing activity.

    Science.gov (United States)

    Chereddy, Kiran Kumar; Vandermeulen, Gaëlle; Préat, Véronique

    2016-03-01

    Wound treatment remains one of the most prevalent and economically burdensome healthcare issues in the world. Current treatment options are limited and require repeated administrations which led to the development of new therapeutics to satisfy the unmet clinical needs. Many potent wound healing agents were discovered but most of them are fragile and/or sensitive to in vivo conditions. Poly(lactic-co-glycolic acid) (PLGA) is a widely used biodegradable polymer approved by food and drug administration and European medicines agency as an excipient for parenteral administrations. It is a well-established drug delivery system in various medical applications. The aim of the current review is to elaborate the applications of PLGA based drug delivery systems carrying different wound healing agents and also present PLGA itself as a wound healing promoter. PLGA carriers encapsulating drugs such as antibiotics, anti-inflammatory drugs, proteins/peptides, and nucleic acids targeting various phases/signaling cycles of wound healing, are discussed with examples. The combined therapeutic effects of PLGA and a loaded drug on wound healing are also mentioned. © 2016 by the Wound Healing Society.

  8. Operando studies of all-vanadium flow batteries: Easy-to-make reference electrode based on silver-silver sulfate

    Science.gov (United States)

    Ventosa, Edgar; Skoumal, Marcel; Vázquez, Francisco Javier; Flox, Cristina; Morante, Joan Ramon

    2014-12-01

    In-depth evaluation of the electrochemical performance of all-vanadium redox flow batteries (VRFBs) under operando conditions requires the insertion of a reliable reference electrode in the battery cell. In this work, an easy-to-make reference electrode based on silver-silver sulfate is proposed and described for VRFBs. The relevance and feasibility of the information obtained by inserting the reference electrode is illustrated with the study of ammoxidized graphite felts. In this case, we show that the kinetic of the electrochemical reaction VO2+/VO2+ is slower than that of V2+/V3+ at the electrode. While the slow kinetics at the positive electrode limits the voltage efficiency, the operating potential of the negative electrode, which is outside the stability widow of water, reduces the coulombic efficiency due to the hydrogen evolution.

  9. Wound Healing Activity of Topical Application Forms Based on Ayurveda

    OpenAIRE

    Datta, Hema Sharma; Mitra, Shankar Kumar; Patwardhan, Bhushan

    2011-01-01

    The traditional Indian medicine—Ayurveda, describes various herbs, fats, oils and minerals with anti-aging as well as wound healing properties. With aging, numerous changes occur in skin, including decrease in tissue cell regeneration, decrease in collagen content, loss of skin elasticity and mechanical strength. We prepared five topical anti-aging formulations using cow ghee, flax seed oil, Phyllanthus emblica fruits, Shorea robusta resin, Yashada bhasma as study materials. For preliminary e...

  10. Development and Antibacterial Activity of Cashew Gum-Based Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Maria José dos S. Soares

    2013-03-01

    Full Text Available The present study describes the development of a green synthesis of silver nanoparticles reduced and stabilized by exuded gum from Anacardium occidentale L. and evaluates in vitro their antibacterial and cytotoxic activities. Characterization of cashew gum-based silver nanoparticles (AgNPs was carried out based on UV–Vis spectroscopy, transmission electron microscopy and dynamic light scattering analysis which revealed that the synthesized silver nanoparticles were spherical in shape, measuring about 4 nm in size with a uniform dispersal. AgNPs presented antibacterial activity, especially against Gram-negative bacteria, in concentrations where no significant cytotoxicity was observed.

  11. Chitosan-based films composites for wound healing purposes

    International Nuclear Information System (INIS)

    Alves, Natali de O.; Silva, Gabriela T. da; Schulz, Gracelie A.S.; Fajardo, Andre R.

    2015-01-01

    Chitosan has been extensively applied in the developing of biomaterials due to its desirable good physico-chemical and biological properties. According to this, here films composite of chitosan, poly(vinyl alcohol) and bovine bone powder were prepared by casting willing to be applied in wound healing purposes. Moreover, the first step was the developing of a suitable method to obtain bovine bone powder, which was utilized here as filler. All the materials and films were fully characterized by FTIR, DRX and thermal analysis. Water uptake capacity was measured by swelling assays. (author)

  12. Evaluation of bacterial nanocellulose-based uniform wound dressing for large area skin transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Lina [Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); National Engineering Research Center for Nano-Medicine, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhou, Ping [Institute of Organ Transplant of Tongji Hospital, Huazhong University of Science and Technology, Wuhan (China); Zhang, Shengmin [Advanced Biomaterials and Tissue Engineering Center, Huazhong University of Science and Technology, Wuhan (China); Yang, Guang, E-mail: yang_sunny@yahoo.com [Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); National Engineering Research Center for Nano-Medicine, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2013-07-01

    Bacterial nanocellulose (BNC) was biosynthesized by Gluconacetobacter xylinus. The surface area, physicochemical structure and morphology of the materials were characterized. Here provides a method for an efficient production of uniform BNC, which is beneficial for the fast characterization and evaluation of BNC. In vitro cytotoxicity of the materials was evaluated by the proliferation, the adhesion, the viability and the morphology of NIH/3T3 cells. Low cytotoxicity of the BNC was observed, and micrographs demonstrate a good proliferation and adhesion of NIH/3T3 cells on BNC. Large area full-thickness skin defects were made on the back of C57BL/6 mice in animal surgery. The wounds were transplanted with BNC films and the results compared to those in a control group. The rehabilitation of the wound surfaces and the pathological sections of mice were investigated and are discussed. Histological examinations demonstrated faster and better healing effect and lower inflammatory response in the BNC group than those in the control group. Preliminary results on wound dressings from BNC show a curative effect promoting the healing of epithelial tissue. BNC is a promising natural polymer with medical applications in wound dressings. - Highlights: • BNC is expected to be a promising material in wound healing and skin transplantation. • We studied surface area, physicochemical structures and morphology of uniform BNC. • Cyto-evaluation results of BNC-based wound dressing show a good biocompatibility. • Large area skin transplantation experiments suggest a good performance of healing.

  13. Evaluation of bacterial nanocellulose-based uniform wound dressing for large area skin transplantation

    International Nuclear Information System (INIS)

    Fu, Lina; Zhou, Ping; Zhang, Shengmin; Yang, Guang

    2013-01-01

    Bacterial nanocellulose (BNC) was biosynthesized by Gluconacetobacter xylinus. The surface area, physicochemical structure and morphology of the materials were characterized. Here provides a method for an efficient production of uniform BNC, which is beneficial for the fast characterization and evaluation of BNC. In vitro cytotoxicity of the materials was evaluated by the proliferation, the adhesion, the viability and the morphology of NIH/3T3 cells. Low cytotoxicity of the BNC was observed, and micrographs demonstrate a good proliferation and adhesion of NIH/3T3 cells on BNC. Large area full-thickness skin defects were made on the back of C57BL/6 mice in animal surgery. The wounds were transplanted with BNC films and the results compared to those in a control group. The rehabilitation of the wound surfaces and the pathological sections of mice were investigated and are discussed. Histological examinations demonstrated faster and better healing effect and lower inflammatory response in the BNC group than those in the control group. Preliminary results on wound dressings from BNC show a curative effect promoting the healing of epithelial tissue. BNC is a promising natural polymer with medical applications in wound dressings. - Highlights: • BNC is expected to be a promising material in wound healing and skin transplantation. • We studied surface area, physicochemical structures and morphology of uniform BNC. • Cyto-evaluation results of BNC-based wound dressing show a good biocompatibility. • Large area skin transplantation experiments suggest a good performance of healing

  14. Charge Transfer Based Colorimetric Detection of Silver Ion

    Energy Technology Data Exchange (ETDEWEB)

    Han, Seung Choul; Kim, Kwang Seob; Choi, Soon Kyu; Oh, Jinho; Lee, Jae Wook [Dong-A Univ., Busan (Korea, Republic of)

    2014-05-15

    We have demonstrated the colorimetric chemosensor for detection of Ag{sup +} via formation of nanoparticles which is based on the intramolecular CT interaction between the electron-rich (2,6-dialkoxynaphthalene; Np) moiety and the electron-deficient (methyl viologen; MV{sup 2+}) moiety of a single sensor molecule. Under irradiation of light, Ag{sup +} was reduced to very small silver nanoparticle by CT interaction in the presence of OEGs as flexible recognition moiety of Ag{sup +} and stabilizer for Ag nanoparticles, thus Ag nanoparticles resulted to reddish brown in the color change of sensor solution, gradually. Therefore, the charge-transfer interaction between an electron-deficient and an electron-rich units existing at a sensor molecule can be regarded as a new and efficient method to construct various colorimetric chemosensors. Donor.acceptor interactions or charge transfer (CT) interactions are an important class of non-covalent interactions and have been widely exploited in self-assembling systems. Beyond molecular chemistry, supramolecular chemistry aims at constituting highly complex, functional chemical systems from components held together by intermolecular forces. Chemosensors are the molecules of abiotic origin that bind selectively and reversibly with the analyte with concomitant change in one or more properties of the system. The recognition and signaling of ionic and neutral species of varying complexity is one of the most intensively studied areas of contemporary supramolecular chemistry.

  15. The effect of silver thickness on the enhancement of polymer based SERS substrates

    International Nuclear Information System (INIS)

    Schneidewind, H; Weber, K; Zeisberger, M; Hübner, U; Dellith, A; Cialla-May, D; Mattheis, R; Popp, J

    2014-01-01

    We investigated silver-covered polymer based nanogratings as substrates for surface-enhanced Raman spectroscopy (SERS), in particular with respect to the thickness of the plasmonically active silver film. In order to obtain accurate geometrical input data for the simulation process, we inspected cross sections of the gratings prepared by breaking at cryogenic temperature. We noticed a strong dependence of the simulation results on geometrical variations of the structures. Measurements revealed that an increasing silver film thickness on top of the nanogratings leads to a blue shift of the plasmonic resonance, as predicted by numerical simulations, as well as to an increased field enhancement for an excitation at 488 nm. We found a clear deviation of the experimental data compared to the simulated results for very thin silver films due to an island-like growth at a silver thickness below 20 nm. In order to investigate the SERS activity. we carried out measurements with crystal violet as a model analyte at an excitation wavelength of 488 nm. The SERS enhancement increases up to a silver thickness of about 30 nm, whereas it remains nearly constant for thicker silver films. (paper)

  16. Liquid radiation detectors based on nano-silver surface plasmon resonance phenomena

    International Nuclear Information System (INIS)

    Puiso, J.; Laurikaitiene, J.; Adliene, D.; Prosycevas, I.

    2010-01-01

    The rapid development of micro- and nano-structures containing silver nano-particles is based on their unique physical properties. Despite the new applications of silver nano-particles in nano-medicine are under heavy discussions, silver nano-particles could be used in liquid radiation detectors thanks to the irradiation-induced surface plasmon resonance (SPR) phenomena observed in the colloidal solutions. Silver nitrate (1 mM AgNO 3 ) and sodium citrate (1 wt% and 5 wt% C 6 H 5 O 7 Na 3 ) were used as precursors for the fabrication of colloidal solutions. Prepared solutions were exposed to gamma-rays from a 60 Co gamma therapy unit 'Rokus-M' to varying absorbed doses, from 2 to 250 Gy. A UV/VIS/NIR spectrometer (Avantes-2048) was used for the measurement of the optical properties (absorbance) of the silver solutions. It was found that an initial absorbed dose of 2 Gy induced the formation of spherical silver nano-particles as it was indicated in the absorbance spectrum of the solution, which had a well-pronounced absorption maximum at the wavelength of 410 nm. There is a potential to measure absorbed doses down to around 20 mGy. The SPR peaks at the wavelengths of 500-700 nm were found at the highest investigated doses > 100 Gy, indicating the presence of silver nano-rods. The colour of colloidal solutions ranged from pale yellow to green and was dependent on the absorbed dose. The investigation has shown that density, size and shape of synthesised silver nano-particles are dependent on the absorbed dose and that shape transformations of the particles due to irradiation are possible. Application of colloidal solutions containing silver nano-particles for dosimetric purposes is discussed on the basis of the obtained results. (authors)

  17. Novel silver-based nanoclay as an antimicrobial in polylactic acid food packaging coatings.

    Science.gov (United States)

    Busolo, Maria A; Fernandez, Patricia; Ocio, Maria J; Lagaron, Jose M

    2010-11-01

    This paper presents a comprehensive performance study of polylactic acid (PLA) biocomposites, obtained by solvent casting, containing a novel silver-based antimicrobial layered silicate additive for use in active food packaging applications. The silver-based nanoclay showed strong antimicrobial activity against Gram-negative Salmonella spp. Despite the fact that no exfoliation of the silver-based nanoclay in PLA was observed, as suggested by transmission electron microscopy (TEM) and wide angle X-ray scattering (WAXS) experiments, the additive dispersed nicely throughout the PLA matrix to a nanoscale, yielding nanobiocomposites. The films were highly transparent with enhanced water barrier and strong biocidal properties. Silver migration from the films to a slightly acidified water medium, considered an aggressive food simulant, was measured by stripping voltammetry. Silver migration accelerated after 6 days of exposure. Nevertheless, the study suggests that migration levels of silver, within the specific migration levels referenced by the European Food Safety Agency (EFSA), exhibit antimicrobial activity, supporting the potential application of this biocidal additive in active food-packaging applications to improve food quality and safety.

  18. A sensitive hydrogen peroxide sensor based on leaf-like silver

    International Nuclear Information System (INIS)

    Meng, Zuchao; Zhang, Mingyin; Zhang, Hongfang; Zheng, Jianbin

    2014-01-01

    A novel non-enzymatic hydrogen peroxide sensor based on leaf-like silver was constructed. The leaf-like silver was synthesized on the surface of L-cysteine (L-cys) by electrodeposition. Scanning electron microscopy and electrochemical techniques were used to characterize the leaf-like silver nanoparticles. The sensor showed high electrocatalytic activity towards the reduction of hydrogen peroxide. A wide linear range of 2.5–1.5 mM with a low detection limit of 0.7 µM was obtained. Excellent electrocatalytic activity, large surface-to-volume ratio and efficient electron transport properties of leaf-like silver have enabled stable and highly sensitive performance for the non-enzymatic hydrogen peroxide sensor. (paper)

  19. Evaluating the superiority of honey over silver sulphadiazine dressing in shortening healing duration of burn injury: an evidence-based case report

    Directory of Open Access Journals (Sweden)

    Sandy S. Sopandi

    2013-12-01

    Full Text Available Background: Burn injury is a global health problem associated with major morbidity and mortality. Honey has long been used in wound management due to its ability to accelerate healing rates and prevent infection. This study is conducted to evaluate the efficacy of honey dressing in shortening healing duration of burn injury compared to silver sulphadiazine (SSD.Methods: A PubMed and Proquest database search was conducted to identify relevant studies. The studies were then appraised and ranked based on their validity, importance, and level of evidence.Results: The two studies appraised in this paper supported the supremacy of honey against SSD in shortening healing duration. However, the individual quality of studies involved was low.Conclusion: Honey is an alternative treatment in shortening burn wound healing duration. Further studies are needed to support clinical application of this conclusion. (Med J Indones. 2013;22:243-7. doi: 10.13181/mji.v22i4.608 Keywords: Burn injury, healing duration, honey, silver sulfadiazine

  20. High-yield water-based synthesis of truncated silver nanocubes

    International Nuclear Information System (INIS)

    Chang, Yun-Min; Lu, I-Te; Chen, Chih-Yuan; Hsieh, Yu-Chi; Wu, Pu-Wei

    2014-01-01

    Highlights: • Development of a water-based formula to fabricate truncated Ag nanocubes. • The sample exhibits (1 0 0), (1 1 0), and (1 1 1) on the facets, edges, and corners. • The sample shows three characteristic absorption peaks due to plasma resonance. -- Abstract: A high-yield water-based hydrothermal synthesis was developed using silver nitrate, ammonia, glucose, and cetyltrimethylammonium bromide (CTAB) as precursors to synthesize truncated silver nanocubes with uniform sizes and in large quantities. With a fixed CTAB concentration, truncated silver nanocubes with sizes of 49.3 ± 4.1 nm were produced when the molar ratio of glucose/silver cation was maintained at 0.1. The sample exhibited (1 0 0), (1 1 0), and (1 1 1) planes on the facets, edges, and corners, respectively. In contrast, with a slightly larger glucose/silver cation ratio of 0.35, well-defined nanocubes with sizes of 70.9 ± 3.8 nm sizes were observed with the (1 0 0) plane on six facets. When the ratio was further increased to 1.5, excess reduction of silver cations facilitated the simultaneous formation of nanoparticles with cubic, spherical, and irregular shapes. Consistent results were obtained from transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and UV–visible absorption measurements

  1. High-yield water-based synthesis of truncated silver nanocubes

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yun-Min; Lu, I-Te; Chen, Chih-Yuan; Hsieh, Yu-Chi; Wu, Pu-Wei, E-mail: ppwu@mail.nctu.edu.tw

    2014-02-15

    Highlights: • Development of a water-based formula to fabricate truncated Ag nanocubes. • The sample exhibits (1 0 0), (1 1 0), and (1 1 1) on the facets, edges, and corners. • The sample shows three characteristic absorption peaks due to plasma resonance. -- Abstract: A high-yield water-based hydrothermal synthesis was developed using silver nitrate, ammonia, glucose, and cetyltrimethylammonium bromide (CTAB) as precursors to synthesize truncated silver nanocubes with uniform sizes and in large quantities. With a fixed CTAB concentration, truncated silver nanocubes with sizes of 49.3 ± 4.1 nm were produced when the molar ratio of glucose/silver cation was maintained at 0.1. The sample exhibited (1 0 0), (1 1 0), and (1 1 1) planes on the facets, edges, and corners, respectively. In contrast, with a slightly larger glucose/silver cation ratio of 0.35, well-defined nanocubes with sizes of 70.9 ± 3.8 nm sizes were observed with the (1 0 0) plane on six facets. When the ratio was further increased to 1.5, excess reduction of silver cations facilitated the simultaneous formation of nanoparticles with cubic, spherical, and irregular shapes. Consistent results were obtained from transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and UV–visible absorption measurements.

  2. Early use of negative pressure therapy in combination with silver dressings in a difficult breast abscess.

    Science.gov (United States)

    Richards, Alastair J; Hagelstein, Sue M; Patel, Girish K; Ivins, Nicola M; Sweetland, Helen M; Harding, Keith G

    2011-12-01

    Combining silver-based dressings with negative pressure therapy after radical excision of chronically infected breast disease is a novel application of two technologies. One patient with complex, chronic, infected breast disease underwent radical excision of the affected area and was treated early with a combination of silver-based dressings and topical negative pressure therapy. The wound was then assessed sequentially using clinical measurements of wound area and depth, pain severity scores and level of exudation. It is possible to combine accepted techniques with modern dressing technologies that result in a positive outcome. In this case, the combination of a silver-based dressing with negative pressure therapy following radical excision proved safe and was well tolerated by the patient. Full epithelisation of the wound was achieved and there was no recurrence of the infection for the duration of the treatment. © 2011 The Authors. © 2011 Blackwell Publishing Ltd and Medicalhelplines.com Inc.

  3. Image-Based Measurement of H2O2 Reaction-Diffusion in Wounded Zebrafish Larvae.

    Science.gov (United States)

    Jelcic, Mark; Enyedi, Balázs; Xavier, João B; Niethammer, Philipp

    2017-05-09

    Epithelial injury induces rapid recruitment of antimicrobial leukocytes to the wound site. In zebrafish larvae, activation of the epithelial NADPH oxidase Duox at the wound margin is required early during this response. Before injury, leukocytes are near the vascular region, that is, ∼100-300 μm away from the injury site. How Duox establishes long-range signaling to leukocytes is unclear. We conceived that extracellular hydrogen peroxide (H 2 O 2 ) generated by Duox diffuses through the tissue to directly regulate chemotactic signaling in these cells. But before it can oxidize cellular proteins, H 2 O 2 must get past the antioxidant barriers that protect the cellular proteome. To test whether, or on which length scales this occurs during physiological wound signaling, we developed a computational method based on reaction-diffusion principles that infers H 2 O 2 degradation rates from intravital H 2 O 2 -biosensor imaging data. Our results indicate that at high tissue H 2 O 2 levels the peroxiredoxin-thioredoxin antioxidant chain becomes overwhelmed, and H 2 O 2 degradation stalls or ceases. Although the wound H 2 O 2 gradient reaches deep into the tissue, it likely overcomes antioxidant barriers only within ∼30 μm of the wound margin. Thus, Duox-mediated long-range signaling may require other spatial relay mechanisms besides extracellular H 2 O 2 diffusion. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. Stem Cell-Containing Hyaluronic Acid-Based Spongy Hydrogels for Integrated Diabetic Wound Healing.

    Science.gov (United States)

    da Silva, Lucília Pereira; Santos, Tírcia Carlos; Rodrigues, Daniel Barreira; Pirraco, Rogério Pedro; Cerqueira, Mariana Teixeira; Reis, Rui Luís; Correlo, Vitor Manuel; Marques, Alexandra Pinto

    2017-07-01

    The detailed pathophysiology of diabetic foot ulcers is yet to be established and improved treatments are still required. We propose a strategy that directs inflammation, neovascularization, and neoinnervation of diabetic wounds. Aiming to potentiate a relevant secretome for nerve regeneration, stem cells were precultured in hyaluronic acid-based spongy hydrogels under neurogenic/standard media before transplantation into diabetic mice full-thickness wounds. Acellular spongy hydrogels and empty wounds were used as controls. Re-epithelialization was attained 4 weeks after transplantation independently of the test groups, whereas a thicker and more differentiated epidermis was observed for the cellular spongy hydrogels. A switch from the inflammatory to the proliferative phase of wound healing was revealed for all the experimental groups 2 weeks after injury, but a significantly higher M2(CD163 + )/M1(CD86 + ) subtype ratio was observed in the neurogenic preconditioned group that also failed to promote neoinnervation. A higher number of intraepidermal nerve fibers were observed for the unconditioned group probably due to a more controlled transition from the inflammatory to the proliferative phase. Overall, stem cell-containing spongy hydrogels represent a promising approach to enhance diabetic wound healing by positively impacting re-epithelialization and by modulating the inflammatory response to promote a successful neoinnervation. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  5. Antioxidant properties of biohybrids based on liposomes and sage silver nanoparticles.

    Science.gov (United States)

    Barbinta-Patrascu, Marcela Elisabeta; Bunghez, Ioana-Raluca; Iordache, Stefan Marian; Badea, Nicoleta; Fierascu, Radu-Claudiu; Ion, Rodica Mariana

    2013-03-01

    This paper is aimed to describe a simple and rapid eco-friendly bottom-up approach for the preparation of antioxidant silver bionanostructures using a leaf extract from sage (Salvia officinalis L.). The bioreduction property of sage in the synthesis of silver nanoparticles was investigated by UV-VIS and Attenuated Total Reflectance Fourier Transform Infrared spectroscopy. During their preparation, the particle size analysis was performed by using Dynamic Light Scattering technique. Ultrasonic irradiation was used to obtain sage silver nanoparticles. The morphology (size and shape) of the herbal silver nanoparticles was evaluated by Scanning Electron Microscopy that revealed the formation of spherical phytonanoparticles with size less than 80 nm. In order to increase their stability and their biocompatibility, the sage silver nanoparticles were introduced in two types of liposomes: soybean lecithin- and Chla-DPPC-lipid vesicles which were prepared by thin film hydration method. X-Ray Fluorescence analysis confirmed the silver presence in liposomes/sage-AgNPs biohybrids. The stability of liposomes/herbal AgNPs bioconstructs was checked by zeta potential measurements. The most stable biohybrids: Chla-DPPC/sage-AgNPs with zeta potential value of -34.2 mV, were characterized by Atomic Force Microscopy revealing the spherical and quasi-spherical shaped profiles of these nanobiohybrids with size less than 96 nm. The antioxidant activity of the silver bionanostructures was evaluated using chemiluminescence assay. The developed eco-friendly silver phytonanostructures based on lipid membranes, nanosilver and sage extract, manifest strong antioxidant properties (between 86.5% and 98.6%).

  6. Polyol synthesis of silver nanoplates: The crystal growth mechanism based on a rivalrous adsorption

    International Nuclear Information System (INIS)

    Luo Xiaolin; Li Zongxiao; Yuan Chunlan; Chen Yashao

    2011-01-01

    Highlights: → Silver nanoplates have been successfully synthesized by polyol reduction in the presence of poly (vinylpyrrolidone) (PVP) and HNO 3 . → Due to the discovery of CN - ions in the solution, a mechanism for the anisotropic growth of silver nanoplates is systematically discussed. → TG, FT-IR and SERS were used to provide some direct evidences of rivalrous adsorption between PVP and CN - ions on the surface of the silver crystals. - Abstract: A polyol reducing approach has been applied to synthesize silver nanoplates with an average thickness of 50 nm and edge length of 3 μm in the presence of poly (vinylpyrrolidone) (PVP) and HNO 3 . X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscropy (TEM), and electron diffraction are used to characterize these silver nanoplates. Findings indicate that the nanoplates are single crystals and with their basal plane as (1 1 1) lattice plane. On the basis of the results from thermogravimetric analysis (TG), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy, a crystal growth mechanism based on the rivalrous adsorption between PVP and CN - ions on the surface of silver nanoplates is supposed to explain the crystal anisotropic growth.

  7. Optimization of silver-dielectric-silver nanoshell for sensing applications

    International Nuclear Information System (INIS)

    Shirzaditabar, Farzad; Saliminasab, Maryam

    2013-01-01

    In this paper, resonance light scattering (RLS) properties of a silver-dielectric-silver nanoshell, based on quasi-static approach and plasmon hybridization theory, are investigated. Scattering spectrum of silver-dielectric-silver nanoshell has two intense and clearly separated RLS peaks and provides a potential for biosensing based on surface plasmon resonance and surface-enhanced Raman scattering. The two RLS peaks in silver-dielectric-silver nanoshell are optimized by tuning the geometrical dimensions. In addition, the optimal geometry is discussed to obtain the high sensitivity of silver-dielectric-silver nanoshell. As the silver core radius increases, the sensitivity of silver-dielectric-silver nanoshell decreases whereas increasing the middle dielectric thickness increases the sensitivity of silver-dielectric-silver nanoshell

  8. Electrospun chitosan-based nanocomposite mats reinforced with chitin nanocrystals for wound dressing

    CSIR Research Space (South Africa)

    Naseria, N

    2014-08-01

    Full Text Available The aim of this study was to develop electrospun chitosan/polyethylene oxide-based randomly oriented fiber mats reinforced with chitin nanocrystals (ChNC) for wound dressing. Microscopy studies showedporous mats of smooth and beadless fibers...

  9. Impact of evidence-based interventions on wound complications after cesarean delivery.

    Science.gov (United States)

    Temming, Lorene A; Raghuraman, Nandini; Carter, Ebony B; Stout, Molly J; Rampersad, Roxane M; Macones, George A; Cahill, Alison G; Tuuli, Methodius G

    2017-10-01

    A number of evidence-based interventions have been proposed to reduce post-cesarean delivery wound complications. Examples of such interventions include appropriate timing of preoperative antibiotics, appropriate choice of skin antisepsis, closure of the subcutaneous layer if subcutaneous depth is ≥2 cm, and subcuticular skin closure with suture rather than staples. However, the collective impact of these measures is unclear. We sought to estimate the impact of a group of evidence-based surgical measures (prophylactic antibiotics administered before skin incision, chlorhexidine-alcohol for skin antisepsis, closure of subcutaneous layer, and subcuticular skin closure with suture) on wound complications after cesarean delivery and to estimate residual risk factors for wound complications. We conducted a secondary analysis of data from a randomized controlled trial of chlorhexidine-alcohol vs iodine-alcohol for skin antisepsis at cesarean delivery from 2011-2015. The primary outcome for this analysis was a composite of wound complications that included surgical site infection, cellulitis, seroma, hematoma, and separation within 30 days. Risk of wound complications in women who received all 4 evidence-based measures (prophylactic antibiotics within 60 minutes of cesarean delivery and before skin incision, chlorhexidine-alcohol for skin antisepsis with 3 minutes of drying time before incision, closure of subcutaneous layer if ≥2 cm of depth, and subcuticular skin closure with suture) were compared with those women who did not. We performed logistic regression analysis limited to patients who received all the evidence-based measures to estimate residual risk factors for wound complications and surgical site infection. Of 1082 patients with follow-up data, 349 (32.3%) received all the evidence-based measures, and 733 (67.7%) did not. The risk of wound complications was significantly lower in patients who received all the evidence-based measures compared with those who

  10. Highly sensitive wearable strain sensor based on silver nanowires and nanoparticles

    Science.gov (United States)

    Shengbo, Sang; Lihua, Liu; Aoqun, Jian; Qianqian, Duan; Jianlong, Ji; Qiang, Zhang; Wendong, Zhang

    2018-06-01

    Here, we propose a highly sensitive and stretchable strain sensor based on silver nanoparticles and nanowires (Ag NPs and NWs), advancing the rapid development of electronic skin. To improve the sensitivity of strain sensors based on silver nanowires (Ag NWs), Ag NPs and NWs were added to polydimethylsiloxane (PDMS) as an aid filler. Silver nanoparticles (Ag NPs) increase the conductive paths for electrons, leading to the low resistance of the resulting sensor (14.9 Ω). The strain sensor based on Ag NPs and NWs showed strong piezoresistivity with a tunable gauge factor (GF) at 3766, and a change in resistance as the strain linearly increased from 0% to 28.1%. The high GF demonstrates the irreplaceable role of Ag NPs in the sensor. Moreover, the applicability of our high-performance strain sensor has been demonstrated by its ability to sense movements caused by human talking, finger bending, wrist raising and walking.

  11. Phenotypic Screening Identifies Synergistically Acting Natural Product Enhancing the Performance of Biomaterial Based Wound Healing

    Directory of Open Access Journals (Sweden)

    Srinivasan Sivasubramanian

    2017-07-01

    Full Text Available The potential of multifunctional wound heal biomaterial relies on the optimal content of therapeutic constituents as well as the desirable physical, chemical, and biological properties to accelerate the healing process. Formulating biomaterials such as amnion or collagen based scaffolds with natural products offer an affordable strategy to develop dressing material with high efficiency in healing wounds. Using image based phenotyping and quantification, we screened natural product derived bioactive compounds for modulators of types I and III collagen production from human foreskin derived fibroblast cells. The identified hit was then formulated with amnion to develop a biomaterial, and its biophysical properties, in vitro and in vivo effects were characterized. In addition, we performed functional profiling analyses by PCR array to understand the effect of individual components of these materials on various genes such as inflammatory mediators including chemokines and cytokines, growth factors, fibroblast stimulating markers for collagen secretion, matrix metalloproteinases, etc., associated with wound healing. FACS based cell cycle analyses were carried out to evaluate the potential of biomaterials for induction of proliferation of fibroblasts. Western blot analyses was done to examine the effect of biomaterial on collagen synthesis by cells and compared to cells grown in the presence of growth factors. This work demonstrated an uncomplicated way of identifying components that synergistically promote healing. Besides, we demonstrated that modulating local wound environment using biomaterials with bioactive compounds could enhance healing. This study finds that the developed biomaterials offer immense scope for healing wounds by means of their skin regenerative features such as anti-inflammatory, fibroblast stimulation for collagen secretion as well as inhibition of enzymes and markers impeding the healing, hydrodynamic properties complemented

  12. Development of honey hydrogel dressing for enhanced wound healing

    International Nuclear Information System (INIS)

    Yusof, Norimah; Ainul Hafiza, A.H.; Zohdi, Rozaini M.; Bakar, Md Zuki A.

    2007-01-01

    Radiation at 25 and 50 kGy showed no effect on the acidic pH of the local honey, Gelam, and its antimicrobial property against Staphylococcus aureus but significantly reduced the viscosity. Honey stored up to 2 years at room temperature retained all the properties studied. Radiation sterilized Gelam honey significantly stimulated the rate of burn wound healing in Sprague-Dawley rats as demonstrated by the increased rate of wound contraction and gross appearance. Gelam honey attenuates wound inflammation; and re-epithelialization was well advanced compared to the treatment using silver sulphadiazine (SSD) cream. To enhance further the use of honey in wound treatment and for easy handling, Gelam honey was incorporated into our hydrogel dressing formulation, which was then cross-linked and sterilized using electron beam at 25 kGy. Hydrogel with 6% of honey was selected based on the physical appearance

  13. Efficacy of a collagen-based dressing in an animal model of delayed wound healing.

    Science.gov (United States)

    Guillemin, Y; Le Broc, D; Ségalen, C; Kurkdjian, E; Gouze, J N

    2016-07-02

    The aim of this study was to evaluate in vitro and in vivo the efficacy of GBT013, a collagen-based dressing, for the treatment of chronic wounds, in a db/db mouse model of diabetes. Macroscopic and histologic analyses of db/db mice wound healing with GBT013 or saline gauze were assessed. The mRNA expression and the proliferation of dermal fibroblast were investigated. Matrix metalloproteinases (MMP)-2 and MMP-9 activities were quantified. In db/db mice, GBT013 improves wound epithelialisation when compared with saline gauze. Histological analysis of scar tissue also shows an enhancement of remodelling associated with no sign of acute inflammation. In addition, GBT013 significantly decreases interleukin (IL)-6 and IL-8, significantly increases tissue inhibitors of metalloproteinases (TIMP)-1 and TIMP-2 fibroblast mRNA expression and significantly reduces in vitro MMP-2 and MMP-9 enzymatic activities. Moreover, GBT013 allows cell growth inside the matrix and stimulates proliferation of human dermal fibroblast. By contributing to restore MMPs/TIMPs balance, GBT013 may function in all key stages of wound healing, such as inflammation, proliferation and tissue remodelling, and ultimately may provide a favourable environment for skin repair. This work was supported by Genbiotech, the R&D subsidiary of Laboratoires Genévrier, a pharmaceutical company.

  14. A PEGylated Fibrin-Based Wound Dressing with Antimicrobial and Angiogenic Activity

    Science.gov (United States)

    2011-04-13

    activity SSD–CSM particles were impregnated in polyethylene glycol (PEGylated) fibrin gels. In vitro drug release studies showed that a burst release of...promote revascularization. Silver sulfadiazine (SSD) is a broad spectrum antimicrobial agent that controls yeasts, molds, other types of fungi , and...site is currently thought to be a crucial early event in the tissue regeneration process [23]. We have recently shown that a polyethylene glycol-based

  15. ANTISEPTIC SPRAY BASED ON STABILIZED SILVER PARTICLES: AN ANALYSIS OF ANTISEPTIC PROPERTIES AND COMPREHENSIVE COMPARISON

    Directory of Open Access Journals (Sweden)

    Manuilov, A.M.

    2018-04-01

    Full Text Available Introduction. It's known that some antiseptic sprays based on alcohols can provoke the formation of multi-resistant strains of pathogenic microorganisms. In addition, alcoholic antiseptics has a number of restrictions to use, for example, they can't to be used in even the presence of micro-trauma on the skin, their ingression into the body and mucous membranes is unacceptable. Alternative can be natural antiseptics based on colloidal silver or silver nanoparticles, as well as silver in ionic form. However, such antiseptics has low efficacy against the most dangerous strains. Company Modern Biochem Technologies Ltd. announced the development of a portable device that generates a natural and safe antiseptic Dew, based on stabilized silver particles. Antiseptic Dew surpasses the vast majority of antiseptics based on silver, and is not inferior in effectiveness to antiseptics based on alcohols. This work is devoted to testing the declared characteristics of Dew and its comparison with antiseptics based on colloidal silver, silver nanoparticles and isopropyl alcohol. Materials and methods. To test the antiseptic effect of these agents, we used four test strains from the American Type Culture Collection: E. Coli ATCC 25922, Staphylococcus Aureus ATCC 25923, Candida Albicans ATCC 885-653 and Proteus Vulgaris ATCC 4636 with billion concentration of colony forming units in 1 ml (108 – 109 CFU/mL, ln CFU/mL = 19.57 ... 20.72. Sowing and screening of cultures were performed on sterile Petri dishes according to the standard procedure. Antiseptic Dew was prepared by prototype provided by Modern Biochem Technologies. The antiseptics of comparison were purchased in Kharkiv, Ukraine. The treatment of contaminated surfaces was performed using mechanical pump sprayers. In accordance with the internal protocol, 1 ml of antiseptic was sprayed from the distance of 10 cm onto the infected surface. To determine the silver content in the Dew, we were used atomic

  16. Soda-based glass fabricated from Thailand quartz sands doped with silver compound

    Science.gov (United States)

    Won-in, Krit; Dararutana, Pisutti

    2012-10-01

    Yellow colored glass which used for luxury art glass in ancient time was fabricated by the addition of silver compound into the molten glass. It was proved that it was actually silver nanoparticle technology. In this work, the SiO2-(Na2O,K2O)-CaO-B2O3-Al2O3-MgO glass system was prepared in the laboratory scale based on local quartz sands from Trat Province, eastern area of Thailand as the silica raw material. Various concentrations of silver nitrate were added. After the complete conventional melting process, the bubble-free yellow glasses were yielded. Physical and optical properties such as density, refractive index and optical absorption spectra were measured. Scanning electron microscope coupled with energy dispersive spectroscopy was carried out to study their morphology. The refractive indices and densities were increased as the increase of the silver contents. Electron micrographs showed the presence of silver nanoparticle in the glass matrix. UV-VIS spectra were in good agreement with that found from SEM measurements and corresponded with the universally accepted. It was also showed that the more brilliance on the surface of the glass products was obtained after firing with a gas torch.

  17. Nonenzymatic glucose sensing based on deposited palladium nanoparticles on epoxy-silver electrodes

    International Nuclear Information System (INIS)

    Gutes, Albert; Carraro, Carlo; Maboudian, Roya

    2011-01-01

    Highlights: → New nonenzymatic glucose sensor material. → Modified epoxy-silver electrodes with palladium nanoparticles. → Simple electroless surface modification. → Wide linear response range. → Easy implementation. - Abstract: A new approach for nonenzymatic glucose sensing, based on a simple modification of epoxy-silver surfaces deposited on the tip of commercial copper electric wires, is presented. Palladium was galvanically displaced on the surface of the epoxy-silver surface in order to obtain metal nanoparticles that act as catalyst for the direct oxidation of glucose. Scanning electron microscopy revealed the formation of the metal nanoparticles. X-ray photoelectron spectroscopy confirmed the metallic nature of the formed nanostructures on the surface. Electrochemical characterization and calibration of the palladium-modified epoxy-silver electrode is reported, obtaining a linear range of 1-20 mM for the detection of glucose with low interference of ascorbic acid and uric acid. A simple 3-step coulometry was used as the detection technique. The developed sensing material is believed to be a great candidate for integration in small devices for clinical essays, due to the simplicity and cost effectiveness of the presented approach, compared to the state-of-the-art devices reported recently in the literature. Simplicity in the coulometry determinations makes these Pd-modified epoxy-silver sensors a good candidate for easy glucose determinations.

  18. 78 FR 2984 - Silver Bear Power, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2013-01-15

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER13-733-000] Silver Bear Power, LLC; Supplemental Notice That Initial Market- Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of Silver Bear...

  19. Measurement of diabetic wounds with optical coherence tomography-based air-jet indentation system and a material testing system.

    Science.gov (United States)

    Choi, M-C; Cheung, K-K; Ng, G Y-F; Zheng, Y-P; Cheing, G L-Y

    2015-11-01

    Material testing system is a conventional but destructive method for measuring the biomechanical properties of wound tissues in basic research. The recently developed optical coherence tomography-based air-jet indentation system is a non-destructive method for measuring these properties of soft tissues in a non-contact manner. The aim of the study was to examine the correlation between the biomechanical properties of wound tissues measured by the two systems. Young male Sprague-Dawley rats with streptozotocin-induced diabetic were wounded by a 6 mm biopsy punch on their hind limbs. The biomechanical properties of wound tissues were assessed with the two systems on post-wounding days 3, 7, 10, 14, and 21. Wound sections were stained with picro-sirius red for analysis on the collagen fibres. Data obtained on the different days were charted to obtain the change in biomechanical properties across the time points, and then pooled to examine the correlation between measurements made by the two devices. Qualitative analysis to determine any correlation between indentation stiffness measured by the air-jet indentation system and the orientation of collagen fibres. The indentation stiffness is significantly negatively correlated to the maximum load, maximum tensile stress, and Young's modulus by the material testing system (all pair-jet indentation system to evaluate the biomechanical properties of wounds in a non-contact manner. It is a potential clinical device to examine the biomechanical properties of chronic wounds in vivo in a repeatable manner.

  20. Regenerative Skin Wound Healing in Mammals: State-of-the-Art on Growth Factor and Stem Cell Based Treatments

    Directory of Open Access Journals (Sweden)

    Bizunesh M. Borena

    2015-04-01

    Full Text Available Mammal skin has a crucial function in several life-preserving processes such as hydration, protection against chemicals and pathogens, initialization of vitamin D synthesis, excretion and heat regulation. Severe damage of the skin may therefore be life-threatening. Skin wound repair is a multiphased, yet well-orchestrated process including the interaction of various cell types, growth factors and cytokines aiming at closure of the skin and preferably resulting in tissue repair. Regardless various therapeutic modalities targeting at enhancing wound healing, the development of novel approaches for this pathology remains a clinical challenge. The time-consuming conservative wound management is mainly restricted to wound repair rather than restitution of the tissue integrity (the so-called “restitutio ad integrum”. Therefore, there is a continued search towards more efficacious wound therapies to reduce health care burden, provide patients with long-term relief and ultimately scarless wound healing. Recent in vivo and in vitro studies on the use of skin wound regenerative therapies provide encouraging results, but more protracted studies will have to determine whether the effect of observed effects are clinically significant and whether regeneration rather than repair can be achieved. For all the aforementioned reasons, this article reviews the emerging field of regenerative skin wound healing in mammals with particular emphasis on growth factor- and stem cell-based therapies.

  1. Gold and silver nanoparticles based superquenching of fluorescence: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Debanjana; Chattopadhyay, Nitin, E-mail: nitin.chattopadhyay@yahoo.com

    2015-04-15

    The short review highlights the recent advances on the gold and silver nanoparticles induced efficient quenching of fluorescence from various fluorophores looking at their promising use as optical rulers and chemo-/bio- sensors. The fluorescence quenching often leads to the increase in the Stern–Volmer constant (K{sub SV}~10{sup 7}–10{sup 10} mol{sup −1} dm{sup 3}) several orders of magnitude higher than the values observed for the normal photochemical quenching processes (~10{sup 2} mol{sup −1} dm{sup 3}). This amplified quenching has been termed as “super-quenching” or “hyper-quenching”. Energy transfer (ET) is established from the donor to the metal nanoparticles rationalizing these fast quenching processes. Considering the distance dependence of the ET process, Förster resonance energy transfer (FRET) and nanometal surface energy transfer (NSET) are ascribed to take place. These sensitive distance dependent phenomena serve as the spectroscopic ruler to measure the intra- or intermolecular distances between the interacting partners. In this account focus has been laid on the size dependent energy transfer and super- and hyper- quenching of the fluorescence of the donor moieties by the nanometals and their probable applications in sensing. Rationalization has been made for the nanoparticle induced huge enhancement in the quenching efficiency. The impact of this review lies in the possible application of these amplified quenching processes in designing high sensitive chemical and biological sensors. - Highlights: • Super efficient quenching of fluorescence of probes by gold and silver nanoparticles is highlighted. • The amplified fluorescence quenching of dyes and polymers is rationalized. • Energy transfer is assigned to be responsible for the efficient quenching process. • Amplified quenching has its potential use in designing sensitive chemical/biological sensors.

  2. Gold and silver nanoparticles based superquenching of fluorescence: A review

    International Nuclear Information System (INIS)

    Ghosh, Debanjana; Chattopadhyay, Nitin

    2015-01-01

    The short review highlights the recent advances on the gold and silver nanoparticles induced efficient quenching of fluorescence from various fluorophores looking at their promising use as optical rulers and chemo-/bio- sensors. The fluorescence quenching often leads to the increase in the Stern–Volmer constant (K SV ~10 7 –10 10 mol −1 dm 3 ) several orders of magnitude higher than the values observed for the normal photochemical quenching processes (~10 2 mol −1 dm 3 ). This amplified quenching has been termed as “super-quenching” or “hyper-quenching”. Energy transfer (ET) is established from the donor to the metal nanoparticles rationalizing these fast quenching processes. Considering the distance dependence of the ET process, Förster resonance energy transfer (FRET) and nanometal surface energy transfer (NSET) are ascribed to take place. These sensitive distance dependent phenomena serve as the spectroscopic ruler to measure the intra- or intermolecular distances between the interacting partners. In this account focus has been laid on the size dependent energy transfer and super- and hyper- quenching of the fluorescence of the donor moieties by the nanometals and their probable applications in sensing. Rationalization has been made for the nanoparticle induced huge enhancement in the quenching efficiency. The impact of this review lies in the possible application of these amplified quenching processes in designing high sensitive chemical and biological sensors. - Highlights: • Super efficient quenching of fluorescence of probes by gold and silver nanoparticles is highlighted. • The amplified fluorescence quenching of dyes and polymers is rationalized. • Energy transfer is assigned to be responsible for the efficient quenching process. • Amplified quenching has its potential use in designing sensitive chemical/biological sensors

  3. Silver nanoparticle-loaded chitosan-starch based films: Fabrication and evaluation of tensile, barrier and antimicrobial properties

    International Nuclear Information System (INIS)

    Yoksan, Rangrong; Chirachanchai, Suwabun

    2010-01-01

    The fabrication of silver nanoparticles was accomplished by γ-ray irradiation reduction of silver nitrate in a chitosan solution. The obtained nanoparticles were stable in the solution for more than six months, and showed the characteristic surface plasmon band at 411 nm as well as a positively charged surface with 40.4 ± 2.0 mV. The silver nanoparticles presented a spherical shape with an average size of 20-25 nm, as observed by TEM. Minimum inhibitory concentration (MIC) against E. coli, S. aureus and B. cereus of the silver nanoparticles dispersed in the γ-ray irradiated chitosan solution was 5.64 μg/mL. The silver nanoparticle-loaded chitosan-starch based films were prepared by a solution casting method. The incorporation of silver nanoparticles led to a slight improvement of the tensile and oxygen gas barrier properties of the polysaccharide-based films, with diminished water vapor/moisture barrier properties. In addition, silver nanoparticle-loaded films exhibited enhanced antimicrobial activity against E. coli, S. aureus and B. cereus. The results suggest that silver nanoparticle-loaded chitosan-starch based films can be feasibly used as antimicrobial materials for food packaging and/or biomedical applications.

  4. A Cost-Effective Transparency-Based Digital Imaging for Efficient and Accurate Wound Area Measurement

    Science.gov (United States)

    Li, Pei-Nan; Li, Hong; Wu, Mo-Li; Wang, Shou-Yu; Kong, Qing-You; Zhang, Zhen; Sun, Yuan; Liu, Jia; Lv, De-Cheng

    2012-01-01

    Wound measurement is an objective and direct way to trace the course of wound healing and to evaluate therapeutic efficacy. Nevertheless, the accuracy and efficiency of the current measurement methods need to be improved. Taking the advantages of reliability of transparency tracing and the accuracy of computer-aided digital imaging, a transparency-based digital imaging approach is established, by which data from 340 wound tracing were collected from 6 experimental groups (8 rats/group) at 8 experimental time points (Day 1, 3, 5, 7, 10, 12, 14 and 16) and orderly archived onto a transparency model sheet. This sheet was scanned and its image was saved in JPG form. Since a set of standard area units from 1 mm2 to 1 cm2 was integrated into the sheet, the tracing areas in JPG image were measured directly, using the “Magnetic lasso tool” in Adobe Photoshop program. The pixel values/PVs of individual outlined regions were obtained and recorded in an average speed of 27 second/region. All PV data were saved in an excel form and their corresponding areas were calculated simultaneously by the formula of Y (PV of the outlined region)/X (PV of standard area unit) × Z (area of standard unit). It took a researcher less than 3 hours to finish area calculation of 340 regions. In contrast, over 3 hours were expended by three skillful researchers to accomplish the above work with traditional transparency-based method. Moreover, unlike the results obtained traditionally, little variation was found among the data calculated by different persons and the standard area units in different sizes and shapes. Given its accurate, reproductive and efficient properties, this transparency-based digital imaging approach would be of significant values in basic wound healing research and clinical practice. PMID:22666449

  5. Argentation gas chromatography revisited: Separation of light olefin/paraffin mixtures using silver-based ionic liquid stationary phases.

    Science.gov (United States)

    Nan, He; Zhang, Cheng; Venkatesh, Amrit; Rossini, Aaron J; Anderson, Jared L

    2017-11-10

    Silver ion or argentation chromatography utilizes stationary phases containing silver ions for the separation of unsaturated compounds. In this study, a mixed-ligand silver-based ionic liquid (IL) was evaluated for the first time as a gas chromatographic (GC) stationary phase for the separation of light olefin/paraffin mixtures. The selectivity of the stationary phase toward olefins can be tuned by adjusting the ratio of silver ion and the mixed ligands. The maximum allowable operating temperature of these stationary phases was determined to be between 125°C and 150°C. Nuclear magnetic resonance (NMR) spectroscopy was used to characterize the coordination behavior of the silver-based IL as well as provide an understanding into the retention mechanism of light olefins. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Collagen-based wound dressings for the treatment of diabetes-related foot ulcers: a systematic review

    Directory of Open Access Journals (Sweden)

    Holmes C

    2013-01-01

    Full Text Available Crystal Holmes,1 James S Wrobel,1 Mark P MacEachern,2 Blaise R Boles31Department of Internal Medicine, University of Michigan Medical School, 2A Alfred Taubman Health Sciences Library, University of Michigan, 3Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, USABackground: Diabetic foot ulcers are a major source of morbidity, limb loss, and mortality. A prolonged inflammatory response, extracellular matrix degradation irregularities, and increased bacteria presence have all been hypothesized as major contributing factors in the delayed healing of diabetic wounds. Collagen components such as fibroblast and keratinocytes are fundamental to the process of wound healing and skin formation. Wound dressings that contain collagen products create a biological scaffold matrix that supports the regulation of extracellular components and promotes wound healing.Methods: A systematic review of studies reporting collagen wound dressings used in the treatment of Diabetic foot ulcers was conducted. Comprehensive searches were run in Ovid MEDLINE, PubMed, EMBASE, and ISI Web of Science to capture citations pertaining to the use of collagen wound dressings in the treatment of diabetic foot ulcers. The searches were limited to human studies reported in English.Results: Using our search strategy, 26 papers were discussed, and included 13 randomized designs, twelve prospective cohorts, and one retrospective cohort, representing 2386 patients with diabetic foot ulcers. Our design was not a formal meta-analysis. In those studies where complete epithelialization, 58% of collagen-treated wounds completely healed (weighted mean 67%. Only 23% of studies reported control group healing with 29% healing (weighted mean 11% described for controls.Conclusion: Collagen- based wound dressings can be an effective tool in the healing of diabetic foot wounds. The current studies show an overall increase in healing rates despite

  7. Silver ion recognition using potentiometric sensor based on recently synthesized isoquinoline-1,3-dione derivatives

    Directory of Open Access Journals (Sweden)

    AJAR KAMAL

    2012-08-01

    Full Text Available The four derivatives of isoquinoline-1,3-dione based on β-lactum (I-IV, have been explored as neutral ionophores for preparing poly(vinylchloride based polymeric membrane electrodes (PME selective to silver(I ions. The addition of sodium tetraphenylborate (NaTPB and dioctylsebacate (DOS as a plasticizer was found to improve the performance of ion selective electrodes. The best performance was obtained with PME-1 based on ionophore I having composition: ionophore (9.2 mg, PVC (100.1 mg, DOS (201.1 mg and NaTPB (1.5 mg in 5 mL tetrahydrofuran. The electrode response was linear with Nernstian slope of 58.44 mV/decade in the concentration range of 1.0 x 10-1 M to 5.0 x 10-6 M and detection limit of 5.83 x 10-6 M. It performs satisfactorily over wide pH range of 1.0-5.5. The proposed sensor can be used over a period of more than three months without any significant drift in potential and shows good selectivity to silver(I ion over a number of cations especially with no interference of mercury(II ions. Sharp end point was obtained when the sensor was used as an indicator electrode for the potentiometric titration of silver(I ions with chloride ions and therefore this electrode (PME-1 could be used for quantitative determination of silver(I ion in synthetic water, silver foil and dental amalgam samples.

  8. The characterization of the antibacterial efficacy of an electrically activated silver ion-based surface system

    Science.gov (United States)

    Shirwaiker, Rohan A.

    There have been growing concerns in the global healthcare system about the eradication of pathogens in hospitals and other health-critical environments. The problem has been aggravated by the overuse of antibiotics and antimicrobial agents leading to the emergence of antibiotic-resistant superbugs such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) which are difficult to kill. Lower immunity of sick patients coupled with the escalating concurrent problem of antibiotic-resistant pathogens has resulted in increasing incidences of hospital acquired (nosocomial) infections. There is an immediate need to control the transmission of such infections, primarily in healthcare environments, by creating touch-contact and work surfaces (e.g., door knobs, push plates, countertops) that utilize alternative antibacterial materials like the heavy metal, silver. Recent research has shown that it is silver in its ionic (Ag+ ) and not elemental form that is antibacterial. Thus, silver-based antibacterial surfaces have to release silver ions directly into the pathogenic environment (generally, an aqueous media) in order to be effective. This dissertation presents the study and analysis of a new silver-based surface system that utilizes low intensity direct electric current (LIDC) for generation of silver ions to primarily inhibit indirect contact transmission of infections. The broader objective of this research is to understand the design, and characterization of the electrically activated silver ion-based antibacterial surface system. The specific objectives of this dissertation include: (1) Developing a comprehensive system design, and identifying and studying its critical design parameters and functional mechanisms. (2) Evaluating effects of the critical design parameters on the antibacterial efficacy of the proposed surface system. (3) Developing a response surface model for the surface system performance. These objectives are

  9. Fungal Burn Wound Infection

    Science.gov (United States)

    1991-01-01

    Aspergillus), Blasto- T he use of effective topical chemotherapeutic agents to myces (Candida), and Zygomycetes ( Mucor , Rhizopus).6 reduce...species, 18%; Mucor species and Rhizopus species, acetate in the morning and silver sulfadiazine in the evening. Prophy- 9.1%; and Microspora species and...sensitivity reports, and the patient’s sue, including one patient who required a hip disarticulation response. to control an invasive Mucor burn wound

  10. Green production of microalgae-based silver chloride nanoparticles with antimicrobial activity against pathogenic bacteria.

    Science.gov (United States)

    da Silva Ferreira, Veronica; ConzFerreira, Mateus Eugenio; Lima, Luís Maurício T R; Frasés, Susana; de Souza, Wanderley; Sant'Anna, Celso

    2017-02-01

    Silver nanoparticles are powerful antimicrobial agents. Here, the synthesis of silver chloride nanoparticles (AgCl-NPs) was consistently evidenced from a commercially valuable microalgae species, Chlorella vulgaris. Incubation of C. vulgaris conditioned medium with AgNO 3 resulted in a medium color change to yellow/brown (with UV-vis absorbance at 415nm), indicative of silver nanoparticle formation. Energy-dispersive X-ray spectroscopy (EDS) of purified nanoparticles confirmed the presence of both silver and chlorine atoms, and X-ray diffraction (XRD) showed the typical pattern of cubic crystalline AgCl-NPs. Transmission electron microscopy (TEM) showed that most particles (65%) were spherical, with average diameter of 9.8±5.7nm. Fourier transform infrared spectroscopy (FTIR) of purified nanoparticle fractions suggested that proteins are the main molecular entities involved in AgCl-NP formation and stabilization. AgCl-NPs (from 10μg/mL) decreased by 98% the growth of Gram-positive Staphylococcus aureus and Gram-negative Klebsiella pneumoniae bacterial pathogens, and had a dose-dependent effect on cell viability, which was measured by automated image-based high content screening (HCS). Ultrastructural analysis of treated bacteria by TEM revealed the abnormal arrangement of the chromosomal DNA. Our findings strongly indicated that the AgCl-NPs from C. vulgaris conditioned medium is a promising 'green' alternative for biomedical application as antimicrobials. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. A high efficacy antimicrobial acrylate based hydrogels with incorporated copper for wound healing application

    Energy Technology Data Exchange (ETDEWEB)

    Vuković, Jovana S.; Babić, Marija M.; Antić, Katarina M.; Miljković, Miona G.; Perić-Grujić, Aleksandra A.; Filipović, Jovanka M.; Tomić, Simonida Lj., E-mail: simonida@tmf.bg.ac.rs

    2015-08-15

    In this study, three series of hydrogels based on 2-hydroxyethyl acrylate and itaconic acid, unloaded, with incorporated copper(II) ions and reduced copper, were successfully prepared, characterized and evaluated as novel wound healing materials. Fourier transform infrared spectroscopy (FTIR) confirmed the expected structure of obtained hydrogels. Scanning electron microscopy (SEM) revealed porous morphology of unloaded hydrogels, and the morphological modifications in case of loaded hydrogels. Thermal characteristics were examined by differential scanning calorimetry (DSC) and the glass transition temperatures were observed in range of 12–50 °C. Swelling study was conducted in wide range of pHs at 37 °C, confirming pH sensitive behaviour for all three series of hydrogels. The in vitro copper release was investigated and the experimental data were analysed using several models in order to elucidate the transport mechanism. The antimicrobial assay revealed excellent antimicrobial activity, over 99% against Escherichia coli, Staphylococcus aureus and Candida albicans, as well as good correlation with the copper release experiments. In accordance with potential application, water vapour transmission rate, oxygen penetration, dispersion characteristics, fluid retention were observed and the suitability of the hydrogels for wound healing application was discussed. - Graphical abstract: Display Omitted - Highlights: • Design and evaluation of novel pH responsive hydrogel series. • Structural, morphological, thermal characterization and controlled copper release. • Antibacterial activity against Escherichia coli and Staphylococcus aureus over 99%. • Antifungal activity against Candida albicans over 99%. • In vitro evaluation studies revealed great potential for wound healing application.

  12. Preparation and characterization of novel antibacterial castor oil-based polyurethane membranes for wound dressing application.

    Science.gov (United States)

    Yari, Abbas; Yeganeh, Hamid; Bakhshi, Hadi; Gharibi, Reza

    2014-01-01

    Preparation of novel antibacterial and cytocompatible polyurethane membranes as occlusive dressing, which can provide moist and sterile environment over mild exudative wounds is considered in this work. In this regard, an epoxy-terminated polyurethane (EPU) prepolymer based on castor oil and glycidyltriethylammonium chloride (GTEAC) as a reactive bactericidal agent were synthesized. Polyurethane membranes were prepared through cocuring of EPU and different content of GTEAC with 1,4-butane diamine. The physical and mechanical properties, as well as cytocompatibility and antibacterial performance of prepared membranes were studied. Depending on their chemical formulations, the equilibrium water absorption and water vapor transmission rate values of the membranes were in ranges of 3-85% and 53-154g m(-2) day(-1), respectively. Therefore, these transparent membranes can maintain for a long period the moist environment over the wounds with low exudates. Detailed cytotoxicity analysis of samples against mouse L929 fibroblast and MCA-3D keratinocyte cells showed good level of cytocompatibility of membranes after purification via extraction of residual unreacted GTEAC moieties. The antibacterial activity of the membranes against Escherichia coli and Staphylococcus aureus bacteria was also studied. The membrane containing 50% GTEAC exhibited an effective antibacterial activity, while showed acceptable cytocompatibility and therefore, can be applied as an antibacterial occlusive wound dressing. Copyright © 2013 Wiley Periodicals, Inc., a Wiley Company.

  13. Technique: imaging earliest tooth development in 3D using a silver-based tissue contrast agent.

    Science.gov (United States)

    Raj, Muhammad T; Prusinkiewicz, Martin; Cooper, David M L; George, Belev; Webb, M Adam; Boughner, Julia C

    2014-02-01

    Looking in microscopic detail at the 3D organization of initiating teeth within the embryonic jaw has long-proved technologically challenging because of the radio-translucency of these tiny un-mineralized oral tissues. Yet 3D image data showing changes in the physical relationships among developing tooth and jaw tissues are vital to understand the coordinated morphogenesis of vertebrate teeth and jaws as an animal grows and as species evolve. Here, we present a new synchrotron-based scanning solution to image odontogenesis in 3D and in histological detail using a silver-based contrast agent. We stained fixed, intact wild-type mice aged embryonic (E) day 10 to birth with 1% Protargol-S at 37°C for 12-32 hr. Specimens were scanned at 4-10 µm pixel size at 28 keV, just above the silver K-edge, using micro-computed tomography (µCT) at the Canadian Light Source synchrotron. Synchrotron µCT scans of silver-stained embryos showed even the earliest visible stages of tooth initiation, as well as many other tissue types and structures, in histological detail. Silver stain penetration was optimal for imaging structures in intact embryos E15 and younger. This silver stain method offers a powerful yet straightforward approach to visualize at high-resolution and in 3D the earliest stages of odontogenesis in situ, and demonstrates the important of studying the tooth organ in all three planes of view. Copyright © 2013 Wiley Periodicals, Inc.

  14. Evidence-based topical management of chronic wounds according to the T.I.M.E. principle.

    Science.gov (United States)

    Klein, Silvan; Schreml, Stephan; Dolderer, Juergen; Gehmert, Sebastian; Niederbichler, Andreas; Landthaler, Michael; Prantl, Lukas

    2013-09-01

    The number of patients suffering from chronic wound healing disorders in Germany alone is estimated to be 2.5-4 million. Therapy related expenses reach 5-8 billion Euros annually. This number is partially caused by costly dressing changes due to non-standardized approaches and the application of non-evidence-based topical wound therapies. The purpose of this paper is to elucidate a straightforward principle for the management of chronic wounds, and to review the available evidence for the particular therapy options. The T.I.M.E.-principle (Tissue management, Inflammation and infection control, Moisture balance, Epithelial [edge] advancement) was chosen as a systematic strategy for wound bed preparation. Literature was retrieved from the PubMed and Cochrane Library databases and subjected to selective analysis. Topical wound management should be carried out according to a standardized principle and should further be synchronized to the phases of wound healing. Despite the broad implementation of these products in clinical practice, often no benefit exists in the rate of healing, when evaluated in meta-analyses or systematic reviews. This insufficient evidence is additionally limited by varying study designs. In case of non-superiority, the results suggest to prefer relatively inexpensive wound dressings over expensive alternatives. Arbitrary endpoints to prove the effectiveness of wound dressings, contribute to the random use of such therapies. Defining rational endpoints for future studies as well as the deployment of structured therapy strategies will be essential for the economical and evidence-based management of chronic wounds. © The Authors | Journal compilation © Blackwell Verlag GmbH, Berlin.

  15. Colorimetric determination of copper ions based on the catalytic leaching of silver from the shell of silver-coated gold nanorods

    International Nuclear Information System (INIS)

    Wang, Xiaokun; Chen, Lingxin; Chen, Ling

    2014-01-01

    We have developed a method for the colorimetric determination of copper ions (Cu 2+ ) that is based on the use of silver-coated gold nanorods (Au–Ag NRs). Its outstanding selectivity and sensitivity result from the catalytic leaching process that occurs between Cu 2+ , thiosulfate (S 2 O 3 2− ), and the surface of the Au–Ag NRs. The intrinsic color of the Au–Ag NRs changes from bright red to bluish green with decreasing thickness of the silver coating. The addition of Cu 2+ accelerates the leaching of silver from the shell caused in the presence of S 2 O 3 2− . This result in a decrease in the thickness of the silver shell which is accompanied a change in color and absorption spectra of the colloidal solution. The shifts in the absorption maxima are linearly related to the concentrations of Cu 2+ over the 3–1,000 nM concentration range (R = 0.996). The method is cost effective and was applied to the determination of Cu 2+ in real water samples. (author)

  16. Light-emitting diodes based on nontoxic zinc-alloyed silver-indium-sulfide (AIZS) nanocrystals

    Science.gov (United States)

    Bhaumik, Saikat; Guchhait, Asim; Pal, Amlan J.

    2014-04-01

    We report solution-processed growth of zinc-alloyed silver-indium-sulfide (AIZS) nanocrystals followed by fabrication and characterization of light-emitting diodes (LEDs) based on such nanostructures. While growing the low dimensional crystals, we vary the ratio between the silver and zinc contents that in turn tunes the bandgap and correspondingly their photoluminescence (PL) emission. We also dope the AIZS nanocrystals with manganese, so that their PL emission, which appears due to a radiative transition between the d-states of the dopants, becomes invariant in energy when the diameter of the quantum dots or the dopant concentration in the nanostructures varies. The LEDs fabricated with such undoped and manganese-doped AIZS nanocrystals emit electroluminescence (EL) that matches the PL spectrum of the respective nanomaterial. The results demonstrate examples of quantum dot LEDs (QDLEDs) based on nontoxic AIZS nanocrystals.

  17. Flexible transparent conductive materials based on silver nanowire networks: a review

    International Nuclear Information System (INIS)

    Langley, Daniel; Giusti, Gaël; Bellet, Daniel; Mayousse, Céline; Celle, Caroline; Simonato, Jean-Pierre

    2013-01-01

    The class of materials combining high electrical or thermal conductivity, optical transparency and flexibility is crucial for the development of many future electronic and optoelectronic devices. Silver nanowire networks show very promising results and represent a viable alternative to the commonly used, scarce and brittle indium tin oxide. The science and technology research of such networks are reviewed to provide a better understanding of the physical and chemical properties of this nanowire-based material while opening attractive new applications. (topical review)

  18. Thermomechanical Modeling of Sintered Silver - A Fracture Mechanics-based Approach: Extended Abstract: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Paret, Paul P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); DeVoto, Douglas J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Narumanchi, Sreekant V [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-01

    Sintered silver has proven to be a promising candidate for use as a die-attach and substrate-attach material in automotive power electronics components. It holds promise of greater reliability than lead-based and lead-free solders, especially at higher temperatures (less than 200 degrees Celcius). Accurate predictive lifetime models of sintered silver need to be developed and its failure mechanisms thoroughly characterized before it can be deployed as a die-attach or substrate-attach material in wide-bandgap device-based packages. We present a finite element method (FEM) modeling methodology that can offer greater accuracy in predicting the failure of sintered silver under accelerated thermal cycling. A fracture mechanics-based approach is adopted in the FEM model, and J-integral/thermal cycle values are computed. In this paper, we outline the procedures for obtaining the J-integral/thermal cycle values in a computational model and report on the possible advantage of using these values as modeling parameters in a predictive lifetime model.

  19. Optical and Electrical Characteristics of Silver Ion Conducting Nanocomposite Solid Polymer Electrolytes Based on Chitosan

    Science.gov (United States)

    Aziz, Shujahadeen B.; Rasheed, Mariwan A.; Abidin, Zul H. Z.

    2017-10-01

    Optical and electrical properties of nanocomposite solid polymer electrolytes based on chitosan have been investigated. Incorporation of alumina nanoparticles into the chitosan:silver triflate (AgTf) system broadened the surface plasmon resonance peaks of the silver nanoparticles and shifted the absorption edge to lower photon energy. A clear decrease of the optical bandgap in nanocomposite samples containing alumina nanoparticles was observed. The variation of the direct-current (DC) conductivity and dielectric constant followed the same trend with alumina concentration. The DC conductivity increased by two orders of magnitude, which can be attributed to hindrance of silver ion reduction. Transmission electron microscopy was used to interpret the space-charge and blocking effects of alumina nanoparticles on the DC conductivity and dielectric constant. The ion conduction mechanism was interpreted based on the dependences of the electrical and dielectric parameters. The dependence of the DC conductivity on the dielectric constant is explained empirically. Relaxation processes associated with conductivity and viscoelasticity were distinguished based on the incomplete semicircular arcs in plots of the real and imaginary parts of the electric modulus.

  20. Towards Environmentally-benign Nanoengineering: Antimicrobial Nanoparticles Based on Silver-infused Lignin Cores

    Science.gov (United States)

    Richter, Alexander Philipp

    Engineered nanomaterials are capable of solving challenges in industries important to society such as energy, agriculture, and health care. Antimicrobial silver nanoparticles (AgNPs) are the most widely used nanoparticles by number of commercial products in commerce today. However, the increased introduction of AgNPs in industrial applications may lead to discharge of persistent nanoparticles in the environment and undesired impacts on living organisms. This dissertation will present a new class of antimicrobial environmentallybenign nanoparticles (EbNPs) designed with green chemistry principles, which can serve as highly efficient microbicide substitutes of the AgNPs. The EbNP core is made of biodegradable lignin, and is infused with an optimal amount of silver ions. We report on the fabrication of environmentally benign nanoparticles (EbNPs) using two types of lignin precursors with simple, inexpensive, and non-toxic processes, (i) by employing a solvent exchange precipitation method at room temperature and (ii) by applying an environmentally friendly water-based acid precipitation method. The synthesis of Organosolv (High Purity Lignin) nanoparticles via antisolvent flash precipitation method in water resulted in particles in the size range of 45 to 250 nm in diameter. We investigate the synthesis parameters of Kraft (Indulin AT) lignin nanoparticles by flash precipitation induced by pH drop in ethylene glycol. Furthermore, we evaluate the ionic strength and pH stability of both lignin nanoparticle suspensions and highlight differences in the systems. After silver ion infusion of Indulin AT nanoparticles followed by surface modification, we show that the EbNPs exhibit higher antimicrobial activity towards Gram-negative human pathogens Escherichia coli and Pseudomonas aeruginosa and Gram-positive human pathogens Staphylococcus epidermidis in direct comparison with silver nanoparticles and silver nitrate solution, and that the particles are effective against

  1. Fabrication And Properties Of Silver Based Multiwall Carbon Nanotube Composite Prepared By Spark Plasma Sintering Method

    Directory of Open Access Journals (Sweden)

    Lis M.

    2015-06-01

    Full Text Available The paper presents results of investigations of the obtained nanocomposite materials based on silver with addition of multiwall carbon nanotubes. The powder of carbon nanotubes content from 0.1 to 3 wt. % was produced by application of powder metallurgy methods, through mixing and high-energetic milling, and also chemical methods. Modification of carbon nanotubes included electroless deposition of silver particles on the carbon nanotube active surfaces and chemical reduction with strong reducing agent – sodium borohydride (NaBH4. The obtained powder mixtures were consolidated by SPS – Spark Plasma Sintering method. The formed composites were subjected to tests of relative density, electrical conductivity and electro-erosion properties. Detailed examinations of the structure with application of X-ray microanalysis, with consideration of carbon nanotubes distribution, were also carried out. The effect of manufacturing methods on properties of the obtained composites was observed.

  2. Size measurement of gold and silver nanostructures based on their extinction spectrum: limitations and extensions

    Directory of Open Access Journals (Sweden)

    A A Ashkarran

    2013-09-01

    Full Text Available  This paper reports on physical principles and the relations between extinction cross section and geometrical properties of silver and gold nanostructures. We introduce some simple relations for determining geometrical properties of silver and gold nanospheres based on the situation of their plasmonic peak. We also applied, investigated and compared the accuracy of these relations using other published works in order to make clear the effects of shape, size distribution and refractive index of particles’ embedding medium. Finally, we extended the equations to non-spherical particles and investigated their accuracy. We found that modified forms of the equations may lead to more exact results for non-spherical metal particles, but for better results, modified equations should depend on shape and size distribution of particles. It seems that these equations are not applicable to particles with corners sharper than cubes' corners i.e. nanostructures with spatial angles less than π/2 sr.

  3. Optimization and Application of Reflective LSPR Optical Fiber Biosensors Based on Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Jiangping Chen

    2015-05-01

    Full Text Available In this study, we developed a reflective localized surface plasmon resonance (LSPR optical fiber sensor, based on silver nanoparticles (Ag NPs. To enhance the sensitivity of the LSPR optical sensor, two key parameters were optimized, the length of the sensing area and the coating time of the Ag NPs. A sensing length of 1.5 cm and a 1-h coating time proved to be suitable conditions to produce highly sensitive sensors for biosensing. The optimized sensor has a high refractive index sensitivity of 387 nm/RIU, which is much higher than that of other reported individual silver nanoparticles in solutions. Moreover, the sensor was further modified with antigen to act as a biosensor. Distinctive wavelength shifts were found after each surface modification step. In addition, the reflective LSPR optical fiber sensor has high reproducibility and stability.

  4. Cost-Effectiveness Analysis in Comparing Alginate Silver Dressing with Silver Zinc Sulfadiazine Cream in the Treatment of Pressure Ulcers

    Directory of Open Access Journals (Sweden)

    Apirag Chuangsuwanich

    2013-09-01

    Full Text Available BackgroundThe treatment of pressure ulcers is complicated, given the various wound dressing products available. The cost of different treatments varies and the cost-effectiveness of each product has not been thoroughly evaluated. We compare two wound dressing protocols-alginate silver dressing (AlSD and silver zinc sulfadiazine cream (AgZnSD with regard to wound healing and cost-effectiveness.MethodsPatients with grade III or IV sacral or trochanteric pressure ulcers were eligible for this prospective, randomized controlled trial. The patients were randomized to receive one of the two dressings for an eight-week period. The criteria of efficacy were based on the Pressure Ulcer Scale for Healing (PUSH scoring tool. The cost of treatment was also assessed.ResultsTwenty patients (12 women and 8 men were randomly assigned to receive either AlSD (n=10 or AgZnSD cream (n=10. The demographic data and wound characteristics were comparable in the two groups. The two groups showed no significant difference in the reduction of PUSH score, wound size, or volume of exudate. The tissue type score was significantly lower in the AlSD group (3.15±0.68-1.85±0.68 vs. 2.73±0.79-2.2±0.41; P=0.015. The cost of treatment was significantly lower in the AlSD group (377.17 vs. 467.74 USD, respectively; P<0.0001.ConclusionsAlginate silver dressing could be effectively used in the treatment of grade III and IV pressure ulcers. It can improve wound tissue characteristics and is cost-effective.

  5. Radiotherapy fiber dosimeter probes based on silver-only coated hollow glass waveguides

    Science.gov (United States)

    Darafsheh, Arash; Melzer, Jeffrey E.; Harrington, James A.; Kassaee, Alireza; Finlay, Jarod C.

    2018-01-01

    Manifestation of Čerenkov radiation as a contaminating signal is a significant issue in radiation therapy dose measurement by fiber-coupled scintillator dosimeters. To enhance the scintillation signal transmission while minimizing Čerenkov radiation contamination, we designed a fiber probe using a silver-only coated hollow waveguide (HWG). The HWG with scintillator inserted in its tip, embedded in tissue-mimicking phantoms, was irradiated with clinical electron and photon beams generated by a medical linear accelerator. Optical spectra of the irradiated tip were taken using a fiber spectrometer, and the signal was deconvolved with a linear fitting algorithm. The resultant decomposed spectra of the scintillator with and without Čerenkov correction were in agreement with measurements performed by a standard electron diode and ion chamber for electron and photon beam dosimetry, respectively, indicating the minimal effect of Čerenkov contamination in the HWG-based dosimeter. Furthermore, compared with a silver/dielectric-coated HWG fiber dosimeter design, we observed higher signal transmission in the design based on the use of silver-only HWG.

  6. Photochemically synthesized heparin-based silver nanoparticles: an antimicrobial activity study

    Science.gov (United States)

    Rodriguez-Torres, Maria del Pilar; Acosta-Torres, Laura Susana; Díaz-Torres, Luis Armando

    2017-08-01

    The antimicrobial activity of silver nanoparticles has been extensively studied in the last years. Such nanoparticles constitute a potential and promising approach for the development of new antimicrobial systems especially due to the fact that several microorganisms are developing resistance to some already existing antimicrobial agents, therefore making antibacterial and antimicrobial studies on alternative materials necessary to overcome this issue. Silver nanoparticle concentration and size are determining factors on the antimicrobial activity of these nano systems. Heparin is a polysaccharide that belongs to the glycosaminoglycans (GAGs) family, molecules formed by a base disaccharide whose components are joined by a glycosidic linkage that is a repeating unit along their structure. It is highly sulfated making it a negatively charged material that is also widely used as an anticoagulant in Medicine because its biocompatibility besides it is also produced within the human body, specifically in the mast cells. Heparin alone possesses antimicrobial activity although it has not been studied very much in detail, it only has been demonstrated that it inhibits E. coli, P. aeruginosa, S. aureus and S. epidermidis, so taking this into account, this study is dedicated to assess UV photochemically-synthesized (λ=254 nm) heparin-based silver nanoparticles antimicrobial activity using the agar disk diffusion method complemented by the broth microdilution method to estimate de minimum inhibitory concentration (MIC), that is the lowest concentration at which an antimicrobial will inhibit visible growth of a microorganism. The strains used were the ones aforementioned to assess the antimicrobial activity degree these heparinbased nanoparticles exhibit.

  7. A review on polymeric hydrogel membranes for wound dressing applications: PVA-based hydrogel dressings

    Directory of Open Access Journals (Sweden)

    Elbadawy A. Kamoun

    2017-05-01

    Full Text Available This review presents the past and current efforts with a brief description on the featured properties of hydrogel membranes fabricated from biopolymers and synthetic ones for wound dressing applications. Many endeavors have been exerted during past ten years for developing new artificial polymeric membranes, which fulfill the demanded conditions for the treatment of skin wounds. This review mainly focuses on representing specifications of ideal polymeric wound dressing membranes, such as crosslinked hydrogels compatible with wound dressing purposes. But as the hydrogels with single component have low mechanical strength, recent trends have offered composite or hybrid hydrogel membranes to achieve the typical wound dressing requirements.

  8. Polyox and carrageenan based composite film dressing containing anti-microbial and anti-inflammatory drugs for effective wound healing.

    Science.gov (United States)

    Boateng, Joshua S; Pawar, Harshavardhan V; Tetteh, John

    2013-01-30

    Polyethylene oxide (Polyox) and carrageenan based solvent cast films have been formulated as dressings for drug delivery to wounds. Films plasticised with glycerol were loaded with streptomycin (30%, w/w) and diclofenac (10%, w/w) for enhanced healing effects in chronic wounds. Blank and drug loaded films were characterised by texture analysis (for mechanical and mucoadhesive properties), scanning electron microscopy, differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy. In addition, swelling, in vitro drug release and antibacterial studies were conducted to further characterise the films. Both blank and drug loaded films showed a smooth, homogeneous surface morphology, excellent transparency, high elasticity and acceptable tensile (mechanical) properties. The drug loaded films showed a high capacity to absorb simulated wound fluid and significant mucoadhesion force which is expected to allow effective adherence to and protection of the wound. The films showed controlled release of both streptomycin and diclofenac for 72 h. These drug loaded films produced higher zones of inhibition against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli compared to the individual drugs zones of inhibition. Incorporation of streptomycin can prevent and treat chronic wound infections whereas diclofenac can target the inflammatory phase of wound healing to relieve pain and swelling. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Marine-derived biological macromolecule-based biomaterials for wound healing and skin tissue regeneration.

    Science.gov (United States)

    Chandika, Pathum; Ko, Seok-Chun; Jung, Won-Kyo

    2015-01-01

    Wound healing is a complex biological process that depends on the wound condition, the patient's health, and the physicochemical support given through external materials. The development of bioactive molecules and engineered tissue substitutes to provide physiochemical support to enhance the wound healing process plays a key role in advancing wound-care management. Thus, identification of ideal molecules in wound treatment is still in progress. The discovery of natural products that contain ideal molecules for skin tissue regeneration has been greatly advanced by exploration of the marine bioenvironment. Consequently, tremendously diverse marine organisms have become a great source of numerous biological macromolecules that can be used to develop tissue-engineered substitutes with wound healing properties. This review summarizes the wound healing process, the properties of macromolecules from marine organisms, and the involvement of these molecules in skin tissue regeneration applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. A simple concept for covering pressure sores: wound edge-based propeller perforator flap.

    Science.gov (United States)

    Kelahmetoglu, Osman; Van Landuyt, Koenraad; Yagmur, Caglayan; Sommeling, Casper E; Keles, Musa K; Tayfur, Volkan; Simsek, Tekin; Demirtas, Yener; Guneren, Ethem

    2017-12-01

    We present a new surgical modification to allow propeller perforator flaps to cover pressure sores at various locations. We used a propeller perforator flap concept based on the detection of newly formed perforator vessels located 1 cm from the wound margin and stimulated by the chronic inflammation process. Between January 2009 and January 2017, 33 wound edge-based propeller perforator flaps were used to cover pressure sores at various locations in 28 patients. In four cases more than one flap was used on the same patient. The patients comprised 18 males and 10 females with a mean age of 41·25 (range, 16-70) years. All patients underwent follow-up for 0-12 months. The mean follow-up duration was 5·03 months. Venous congestion was observed in three flaps that were rotated by 180° (9·1%). However, there was a significant difference between flaps rotated by 90° and 180° according to the complication rate (P = 0·034). Out of 33 flaps, 29 flaps healed uneventfully. Patients were able to sit and lie on their flaps three weeks after surgery. In our study, we were able to obtain satisfying final results using these novel flaps. © 2017 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  11. Cost-effective use of silver dressings for the treatment of hard-to-heal chronic venous leg ulcers

    DEFF Research Database (Denmark)

    Jemec, Gregor B E; Kerihuel, Jean Charles; Ousey, Karen

    2014-01-01

    AIM: To estimate the cost-effectiveness of silver dressings using a health economic model based on time-to-wound-healing in hard-to-heal chronic venous leg ulcers (VLUs). BACKGROUND: Chronic venous ulceration affects 1-3% of the adult population and typically has a protracted course of healing....... METHODS: A decision tree was constructed to evaluate the cost-effectiveness of treatment with silver compared with non-silver dressings for four weeks in a primary care setting. The outcomes: 'Healed ulcer', 'Healing ulcer' or 'No improvement' were developed, reflecting the relative reduction in ulcer...

  12. Surface enhanced Raman scattering of new acridine based fluorophore adsorbed on silver electrode

    Science.gov (United States)

    Solovyeva, Elena V.; Myund, Liubov A.; Denisova, Anna S.

    2015-10-01

    4,5-Bis(N,N-di(2-hydroxyethyl)iminomethyl)acridine (BHIA) is a new acridine based fluoroionophore and a highly-selective sensor for cadmium ion. The direct interaction of the aromatic nitrogen atom with a surface is impossible since there are bulky substituents in the 4,5-positions of the acridine fragment. Nevertheless BHIA molecule shows a reliable SERS spectrum while adsorbed on a silver electrode. The analysis of SERS spectra pH dependence reveals that BHIA species adsorbed on a surface can exist in both non-protonated and protonated forms. The adsorption of BHIA from alkaline solution is accompanied by carbonaceous species formation at the surface. The intensity of such "carbon bands" turned out to be related with the supporting electrolyte (KCl) concentration. Upon lowering the electrode potential the SERS spectra of BHIA do not undergo changes but the intensity of bands decreases. This indicates that the adsorption mechanism on the silver surface is realized via aromatic system of acridine fragment. In case of such an adsorption mechanism the chelate fragment of the BHIA molecule is capable of interaction with the solution components. Addition of Cd2+ ions to a system containing BHIA adsorbed on a silver electrode in equilibrium with the solution leads to the formation of BHIA/Cd2+ complex which desorption causes the loss of SERS signal.

  13. Conductive Adhesive Based on Mussel-Inspired Graphene Decoration with Silver Nanoparticles.

    Science.gov (United States)

    Casa, Marcello; Sarno, Maria; Liguori, Rosalba; Cirillo, Claudia; Rubino, Alfredo; Bezzeccheri, Emanuele; Liu, Johan; Ciambelli, Paolo

    2018-02-01

    Decoration with silver nanoparticles was obtained by coating graphene with a polydopamine layer, able to induce spontaneous metallic nanoparticles formation without any specific chemical interfacial modifier, neither using complex instrumentation. The choice of dopamine was inspired by the composition of adhesive proteins in mussels, related to their robust attach to solid surfaces. The synthesis procedure started from graphite and involved eco-friendly compounds, such as Vitamin C and glucose as reducing agent and water as reaction medium. Silver decorated graphene was inserted as secondary nanofiller in the formulation of a reference conductive adhesive based on epoxy resin and silver flakes. A wide characterization of the intermediate materials obtained along the step procedure for the adhesive preparation was carried out by several techniques. We have found that the presence of nanofiller yields, in addition to an improvement of the thermal conductivity (up to 7.6 W/m · K), a dramatic enhancement of the electrical conductivity of the adhesive. In particular, starting from 3 · 102 S/cm of the reference adhesive, we obtained a value of 4 · 104 S/cm at a nanofiller concentration of 11.5 wt%. The combined double filler conductivity was evaluated by Zallen's model. The effect of the temperature on the resistivity of the adhesive has been also studied.

  14. Silver Fiber Fabric as the Current Collector for Preparation of Graphene- Based Supercapacitors

    International Nuclear Information System (INIS)

    Mehrabi-Matin, Bahareh; Shahrokhian, Saeed; Iraji-zad, Azam

    2017-01-01

    Highlights: • For the first time, silver fiber fabric (SFF) is employed as a current collector.. • rGO is electrophoretically deposited on the surface of SFF. • The electrodes are prepared in various EP deposition times. • The rGO/SFF-10 shows a higher capacitive performance of 172 mF/cm 2 at 4 mA/cm 2 . • The rGO/SFF-10 exhibits of 97% capacitance retention after 5000 cycles. - Abstract: During the past few years, a considerable attention has been devoted to the development of textile- based energy storage devices and wearable electronics applications. In this paper, for the first time, we report a flexible high performance graphene-based supercapacitor using silver fiber fabric as the current collector. The silver fiber fabric offers remarkable advantages such as light weight, mechanical flexibility and ease of integration with electronic textiles, which well-suited for wearable energy storage devices. A new hybrid material of graphene-silver fiber fabric (rGO/SFF) was prepared through a facile electrophoretic deposition of graphene and being used as a binder-free flexible supercapacitor electrode. In order to obtain the optimum condition, the effect of deposition time was investigated and a duration time of 10 minute was selected as an optimum condition. The as-prepared binder-free electrode based on rGO/SFF-10 showed excellent electrochemical performance in the three-electrode configuration using KOH (3 M) as the supporting electrolyte, with the highest capacity of 172 mF/cm 2 at 4 mA/cm 2 and a capacitance retention of 97% after 5000 charge−discharge cycles. The high performance of rGO/SFF electrode is associated to the superior conductivity, high mechanical flexibility as well as good electrochemical stability of the silver fiber fabrics. The results suggest that the prepared electrode is a promising candidate for wearable energy storage applications due to its advantageous properties and the ease of preparation.

  15. Hydrogel Based on Crosslinked Methylcellulose Prepared by Electron Beam Irradiation for Wound Dressing Application

    Directory of Open Access Journals (Sweden)

    Ambyah Suliwarno

    2014-10-01

    Full Text Available The aim of this research is to explore the possibility of methylcellulose polymer to be used as wound dressing material prepared using electron beam technique. The methylcellulose paste solution with various of molecular weight (SM-4, SM-100, SM-400, SM-4000 and SM-8000 at different concentration (15-30% w/v were irradiated by using electron beam on the dose range of 10 kGy up to 40 kGy. Gel fraction and swelling ratio of hydrogels were determined gravimetrically. Tensile strength and elasticity of hydrogels were measured using a universal testing machine. It was found that with the increasing of irradiation dose from 10 up to 40 kGy, gel fraction and tensile strength were increased for all of hydrogels with various of molecular weight. On contrary, the swelling ratio of hydrogels decreased with increasing of irradiation dose. The optimum hydrogels elasticity were obtained from methylcellulose solution with the concentration range of 15-20% with irradiation dose of 20 kGy and showed excellent performance. The hydrogels based on methylcellulose prepared by electron beam irradiation can be considered for wound dressing material.

  16. Formulation and screen printing of water based conductive flake silver pastes onto green ceramic tapes for electronic applications

    International Nuclear Information System (INIS)

    Faddoul, Rita; Reverdy-Bruas, Nadège; Blayo, Anne

    2012-01-01

    Highlights: ► Formulation of water-based pastes. ► Viscosity, yield stress, elastic and viscous modulus determination. ► Screen printing onto green ceramic tapes. ► Rheology effect on line dimensions and electrical properties. ► Resistivity ∼18–33 nΩ m. Minimum width ∼60 μm after sintering. - Abstract: Environmentally friendly, water-based silver pastes, adapted for screen printing, were formulated with different silver contents (67–75%). These pastes allowed screen printing onto low temperature co-fired ceramic (LTCC) of narrow conductive tracks with a 60 μm line width and a 3 × 10 −8 Ω m electrical resistivity. Inks were formulated with a mixture of spherical and flake shape silver particles with 2–4 μm mean diameter. Rheological behaviour of pastes was studied in order to determine its effect on printed lines properties. Prepared inks were then screen printed and sintered under normal atmosphere at 875 °C. As expected, electrical properties depended on silver content. Resistivity values varying from 1.6 × 10 −8 to 3.3 × 10 −8 Ω m were calculated over 36.3 cm line length. These values are very close to bulk silver resistivity (1.6 × 10 −8 Ω m). Compared to previous research and commercial pastes, the newly formulated pastes reached equivalent or even better conductivities with lower silver content (70% by weight).

  17. Screen-printable silver nanoparticulate-based inks for the electrocatalysis of hydrogen peroxide

    OpenAIRE

    Goodison, Alan; Killard, Anthony J.; Morrin, Aoife

    2013-01-01

    The detection of hydrogen peroxide has been shown to be very important in recent years due to its relevant role in many industrial applications as well as biological reactions. We are interested in it as a quantitative marker for oxidase-based biosensor applications where it is produced when substrate (e.g., glucose, cholesterol) is catalysed by its respective oxidase enzyme. Previously, a commercial silver flake-based screen-printing ink (PF-410, Acheson®), when treated with surfactant and s...

  18. The effects of honey compared to silver sulfadiazine for the treatment of burns: A systematic review of randomized controlled trials.

    Science.gov (United States)

    Aziz, Zoriah; Abdul Rasool Hassan, Bassam

    2017-02-01

    Evidence from animal studies and trials suggests that honey may accelerate wound healing. The objective of this review was to assess the effects of honey compared with silver dressings on the healing of burn wounds. Relevant databases for randomized controlled trials (RCTs) of honey compared with silver sulfadiazine (SSD) were searched. The quality of the selected trials was assessed using the Cochrane Risk of Bias Assessment Tool. The primary endpoints considered were wound healing time and the number of infected wounds rendered sterile. Nine RCTs met the inclusion criteria. Based on moderate quality evidence there was a statistically significant difference between the two groups, favoring honey in healing time (MD -5.76days, 95% CI -8.14 to -3.39) and the proportions of infected wounds rendered sterile (RR 2.59; 95% CI 1.58-2.88). The available evidence suggests that honey dressings promote better wound healing than silver sulfadiazine for burns. Copyright © 2016 Elsevier Ltd and ISBI. All rights reserved.

  19. Characterization and antibacterial properties of porous fibers containing silver ions

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Zhaoyang; Fan, Chenxu; Tang, Xiaopeng; Zhao, Jianghui; Song, Yanhua; Shao, Zhongbiao [National Engineering Laboratory for Modern Silk, College of Textile and Engineering, Soochow University, 199 Ren-ai Road, Suzhou 215123 (China); Xu, Lan, E-mail: lanxu@suda.edu.cn [National Engineering Laboratory for Modern Silk, College of Textile and Engineering, Soochow University, 199 Ren-ai Road, Suzhou 215123 (China); Nantong Textile Institute of Soochow University, 58 Chong-chuan Road, Nantong 226018 (China)

    2016-11-30

    Highlights: • Antibacterial electrospun PLA porous fibers containing silver ions were prepared. • Porous structure and porosity of PLA/Ag{sup +} porous fibers were investigated. • The antibacterial effects of PLA/Ag{sup +} porous fibers were studied. • The released mechanism of silver ions in the porous fibers was illustrated. • The porous structure could improve the antibacterial properties. - Abstract: Materials prepared on the base of bioactive silver compounds have become more and more popular. In the present work, the surface morphology, structure and properties, of electrospun Polylactide Polylactic acid (PLA) porous fibers containing various ratios of silver ions were investigated by a combination of X-ray photoelectron spectroscopy (XPS), universal testing machine, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and et al. The biological activities of the proposed porous fibers were discussed in view of the released silver ions concentration. Antibacterial properties of these porous fibers were studied using two bacterial strains: Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA). Results of the antibacterial testing suggested that PLA porous fibers containing silver ions could be used as potent antibacterial wound dressing materials in the biomedical field.

  20. Characterization and antibacterial properties of porous fibers containing silver ions

    International Nuclear Information System (INIS)

    Sun, Zhaoyang; Fan, Chenxu; Tang, Xiaopeng; Zhao, Jianghui; Song, Yanhua; Shao, Zhongbiao; Xu, Lan

    2016-01-01

    Highlights: • Antibacterial electrospun PLA porous fibers containing silver ions were prepared. • Porous structure and porosity of PLA/Ag + porous fibers were investigated. • The antibacterial effects of PLA/Ag + porous fibers were studied. • The released mechanism of silver ions in the porous fibers was illustrated. • The porous structure could improve the antibacterial properties. - Abstract: Materials prepared on the base of bioactive silver compounds have become more and more popular. In the present work, the surface morphology, structure and properties, of electrospun Polylactide Polylactic acid (PLA) porous fibers containing various ratios of silver ions were investigated by a combination of X-ray photoelectron spectroscopy (XPS), universal testing machine, thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and et al. The biological activities of the proposed porous fibers were discussed in view of the released silver ions concentration. Antibacterial properties of these porous fibers were studied using two bacterial strains: Escherichia coli (E. coli) and Methicillin-resistant Staphylococcus aureus (MRSA). Results of the antibacterial testing suggested that PLA porous fibers containing silver ions could be used as potent antibacterial wound dressing materials in the biomedical field.

  1. Biosynthesis of Silver Nanoparticles and Its Applications

    International Nuclear Information System (INIS)

    Firdhouse, M. J.; Lalitha, P.

    2015-01-01

    Silver nanoparticles possess unique properties which find myriad applications such as antimicrobial, anticancer, larvicidal, catalytic, and wound healing activities. Biogenic syntheses of silver nanoparticles using plants and their pharmacological and other potential applications are gaining momentum owing to its assured rewards. This critical review is aimed at providing an insight into the phyto mediated synthesis of silver nanoparticles, its significant applications in various fields, and characterization techniques involved.

  2. Chitosan-based dressings loaded with neurotensin--an efficient strategy to improve early diabetic wound healing.

    Science.gov (United States)

    Moura, Liane I F; Dias, Ana M A; Leal, Ermelindo C; Carvalho, Lina; de Sousa, Hermínio C; Carvalho, Eugénia

    2014-02-01

    One important complication of diabetes mellitus is chronic, non-healing diabetic foot ulcers (DFUs). This study aims to develop and use dressings based on chitosan derivatives for the sustained delivery of neurotensin (NT), a neuropeptide that acts as an inflammatory modulator in wound healing. Three different derivatives, namely N-carboxymethyl chitosan, 5-methyl pyrrolidinone chitosan (MPC) and N-succinyl chitosan, are presented as potential biomaterials for wound healing applications. Our results show that MPC has the best fluid handling capacity and delivery profile, also being non-toxic to Raw 264.7 and HaCaT cells. NT-loaded and non-loaded MPC dressings were applied to control/diabetic wounds to evaluate their in vitro/in vivo performance. The results show that the former induced more rapid healing (50% wound area reduction) in the early phases of wound healing in diabetic mice. A NT-loaded MPC foam also reduced expression of the inflammatory cytokine TNF-α (Pdiabetic skin (P<0.001), significantly increasing fibroblast migration and collagen (COL1A1, COL1A2 and COL3A1) expression and deposition. These results suggest that MPC-based dressings may work as an effective support for sustained NT release to reduce DFUs. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Mesenchymal stem cells delivered in a microsphere-based engineered skin contribute to cutaneous wound healing and sweat gland repair.

    Science.gov (United States)

    Huang, Sha; Lu, Gang; Wu, Yan; Jirigala, Enhe; Xu, Yongan; Ma, Kui; Fu, Xiaobing

    2012-04-01

    Bone-marrow-derived mesenchymal stem cells (BM-MSCs) can contribute to wound healing after skin injury. However, the role of BM-MSCs on repairing skin appendages in renewal tissues is incompletely explored. Moreover, most preclinical studies suggest that the therapeutic effects afforded by BM-MSCs transplantation are short-lived and relatively unstable. To assess whether engrafted bone-marrow-derived mesenchymal stem cells via a delivery system can participate in cutaneous wound healing and sweat-gland repair in mice. For safe and effective delivery of BM-MSCs to wounds, epidermal growth factor (EGF) microspheres were firstly developed to both support cells and maintain appropriate stimuli, then cell-seeded microspheres were incorporated with biomimetic scaffolds and thus fabricated an engineered skin construct with epithelial differentiation and proliferative potential. The applied efficacy was examined by implanting them into excisional wounds on both back and paws of hind legs in mice. After 3 weeks, BM-MSC-engineered skin (EGF loaded) treated wounds exhibited accelerated healing with increased re-epithelialization rates and less skin contraction. Furthermore, histological and immunofluorescence staining analysis revealed sweat glands-like structures became more apparent in BM-MSC-engineered skin (EGF loaded) treated wounds but the number of implanted BM-MSCs were decreased gradually in later phases of healing progression. Our study suggests that BM-MSCs delivered by this EGF microspheres-based engineered skin model may be a promising strategy to repair sweat glands and improve cutaneous wound healing after injury and success in this study might provide a potential benefit for BM-MSCs administration clinically. Copyright © 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

  4. Preparation of SMART wound dressings based on colloidal microgels and textile fibres

    Science.gov (United States)

    Cornelius, Victoria J.; Majcen, Natasa; Snowden, Martin J.; Mitchell, John C.; Voncina, Bojana

    2007-01-01

    Wound dressings and other types of wound healing technologies are experiencing fast-paced development and rapid growth. As the population ages, demand will continue to rise for advanced dressings used to treat chronic wounds, such as pressure ulcers, venous stasis ulcers, and diabetic ulcers. Moist wound dressings, which facilitate natural wound healing in a cost-effective manner, will be increasingly important. In commercially available hydrogel / gauze wound dressings the gel swells to adsorb wound excreta and provide an efficient non adhesive particle barrier. An alternative to hydrogels are microgels. Essentially discrete colloidal gel particles, as a result of their very high surface area to volume ratio compared to bulk gels, they have a much faster response to external stimuli such as temperature or pH. In response to either an increase or decrease in solvent quality these porous networks shrink and swell reversibly. When swollen the interstitial regions within the polymer matrix are available for further chemistry; such as the incorporation of small molecules. The reversible shrinking and swelling as a function of external stimuli provides a novel drug release system. As the environmental conditions of a wound change over its lifetime, tending to increase in pH if there is an infection combining these discrete polymeric particles with a substrate such as cotton, results in a smart wound dressing.

  5. Development, standardization and testing of a bacterial wound infection model based on ex vivo human skin.

    Directory of Open Access Journals (Sweden)

    Christoph Schaudinn

    Full Text Available Current research on wound infections is primarily conducted on animal models, which limits direct transferability of these studies to humans. Some of these limitations can be overcome by using-otherwise discarded-skin from cosmetic surgeries. Superficial wounds are induced in fresh ex vivo skin, followed by intradermal injection of Pseudomonas aeruginosa under the wound. Subsequently, the infected skin is incubated for 20 hours at 37°C and the CFU/wound are determined. Within 20 hours, the bacteria count increased from 107 to 109 bacteria per wound, while microscopy revealed a dense bacterial community in the collagen network of the upper wound layers as well as numerous bacteria scattered in the dermis. At the same time, IL-1alpha and IL-1beta amounts increased in all infected wounds, while-due to bacteria-induced cell lysis-the IL-6 and IL-8 concentrations rose only in the uninfected samples. High-dosage ciprofloxacin treatment resulted in a decisive decrease in bacteria, but consistently failed to eradicate all bacteria. The main benefits of the ex vivo wound model are the use of healthy human skin, a quantifiable bacterial infection, a measureable donor-dependent immune response and a good repeatability of the results. These properties turn the ex vivo wound model into a valuable tool to examine the mechanisms of host-pathogen interactions and to test antimicrobial agents.

  6. Colloidosome-based synthesis of a multifunctional nanostructure of silver and hollow iron oxide nanoparticles

    KAUST Repository

    Pan, Yue; Gao, Jinhao; Zhang, Bei; Zhang, Xixiang; Xu, Bing

    2010-01-01

    nitrate, and iron oxide exposed to the aqueous phase catalyzes the reduction of silver ions to afford a heterodimer of silver and hollow iron oxide nanoparticles. Transmission electron microscopy, selected area electron diffraction, energy-dispersive X

  7. Data on glycerol/tartaric acid-based copolymer containing ciprofloxacin for wound healing applications

    Directory of Open Access Journals (Sweden)

    E. De Giglio

    2016-06-01

    Full Text Available This data article is related to our recently published research paper “Exploiting a new glycerol-based copolymer as a route to wound healing: synthesis, characterization and biocompatibility assessment", De Giglio et al. (Colloids and Surfaces B: Biointerfaces 136 (2015 600–611 [1]. The latter described a new copolymer derived from glycerol and tartaric acid (PGT. Herein, an investigation about the PGT-ciprofloxacin (CIP interactions by means of Fourier Transform Infrared Spectroscopy (FT-IR acquired in Attenuated Total Reflectance (ATR mode and Differential Scanning Calorimetry (DSC was reported. Moreover, CIP release experiments on CIP-PGT patches were performed by High Performance Liquid Chromatography (HPLC at different pH values.

  8. Prospective, double-blinded, randomised controlled trial assessing the effect of an Octenidine-based hydrogel on bacterial colonisation and epithelialization of skin graft wounds in burn patients.

    Science.gov (United States)

    W, Eisenbeiß; F, Siemers; G, Amtsberg; P, Hinz; B, Hartmann; T, Kohlmann; A, Ekkernkamp; U, Albrecht; O, Assadian; A, Kramer

    2012-01-01

    Moist wound treatment improves healing of skin graft donor site wounds. Microbial colonised wounds represent an increased risk of wound infection; while antimicrobially active, topical antiseptics may impair epithelialization. The aim of this prospective randomised controlled clinical trial was to examine the influence of an Octenidine-dihydrochloride (OCT) hydrogel on bacterial colonisation and epithelialization of skin graft donor sites. The study was designed as a randomised, double-blinded, controlled clinical trial. Skin graft donor sites from a total of 61 patients were covered either with 0.05% OCT (n=31) or an OCT-free placebo wound hydrogel (n=30). Potential interaction with wound healing was assessed by measuring the time until 100% re-epithelialization. In addition, microbial wound colonisation was quantitatively determined in all skin graft donor sites. There was no statistically significant difference in the time for complete epithelialization of skin graft donor sites in the OCT and the placebo group (7.3±0.2 vs. 6.9±0.2 days; p=0.236). Microbial wound colonisation was significantly lower in the OCT group than in the placebo group (p=0.014). The OCT-based hydrogel showed no delay in wound epithelialization and demonstrated a significantly lower bacterial colonisation of skin graft donor site wounds.

  9. Electrocontact material based on silver dispersion-strengthened by nickel, titanium, and zinc oxides

    Science.gov (United States)

    Zeer, G. M.; Zelenkova, E. G.; Belousov, O. V.; Beletskii, V. V.; Nikolaev, S. V.; Ledyaeva, O. N.

    2017-09-01

    Samples of a composite electrocontact material based on silver strengthened by the dispersed phases of zinc and titanium oxides have been investigated by the electron microscopy and energy dispersive X-ray spectroscopy. A uniform distribution of the oxide phases containing 2 wt % zinc oxide in the initial charge has been revealed. The increase in the amount of zinc oxide leads to an increase of the size of the oxide phases. It has been shown that at the zinc oxide content of 2 wt %, the minimum wear is observed in the process of electroerosion tests; at 3 wt %, an overheating and welding of the contacts are observed.

  10. Evaluating the superiority of honey over silver sulphadiazine dressing in shortening healing duration of burn injury: an evidence-based case report

    OpenAIRE

    Sandy S. Sopandi

    2013-01-01

    Background: Burn injury is a global health problem associated with major morbidity and mortality. Honey has long been used in wound management due to its ability to accelerate healing rates and prevent infection. This study is conducted to evaluate the efficacy of honey dressing in shortening healing duration of burn injury compared to silver sulphadiazine (SSD).Methods: A PubMed and Proquest database search was conducted to identify relevant studies. The studies were then appraised and ranke...

  11. Thermoelectric Mixed Thick-/Thin Film Microgenerators Based on Constantan/Silver

    Directory of Open Access Journals (Sweden)

    Mirosław Gierczak

    2018-01-01

    Full Text Available This paper describes the design, manufacturing and characterization of newly developed mixed thick-/thin film thermoelectric microgenerators based on magnetron sputtered constantan (copper-nickel alloy and screen-printed silver layers. The thermoelectric microgenerator consists of sixteen thermocouples made on a 34.2 × 27.5 × 0.25 mm3 alumina substrate. One of thermocouple arms was made of magnetron-sputtered constantan (Cu-Ni alloy, the second was a Ag-based screen-printed film. The length of each thermocouple arm was equal to 27 mm, and their width 0.3 mm. The distance between the arms was equal to 0.3 mm. In the first step, a pattern mask with thermocouples was designed and fabricated. Then, a constantan layer was magnetron sputtered over the whole substrate, and a photolithography process was used to prepare the first thermocouple arms. The second arms were screen-printed onto the substrate using a low-temperature silver paste (Heraeus C8829A or ElectroScience Laboratories ESL 599-E. To avoid oxidation of constantan, they were fired in a belt furnace in a nitrogen atmosphere at 550/450 °C peak firing temperature. Thermoelectric and electrical measurements were performed using the self-made measuring system. Two pyrometers included into the system were used for temperature measurement of hot and cold junctions. The estimated Seebeck coefficient, α was from the range 35 − 41 µV/K, whereas the total internal resistances R were between 250 and 3200 ohms, depending on magnetron sputtering time and kind of silver ink (the resistance of a single thermocouple was between 15.5 and 200 ohms.

  12. Digital photography and transparency-based methods for measuring wound surface area.

    Science.gov (United States)

    Bhedi, Amul; Saxena, Atul K; Gadani, Ravi; Patel, Ritesh

    2013-04-01

    To compare and determine a credible method of measurement of wound surface area by linear, transparency, and photographic methods for monitoring progress of wound healing accurately and ascertaining whether these methods are significantly different. From April 2005 to December 2006, 40 patients (30 men, 5 women, 5 children) admitted to the surgical ward of Shree Sayaji General Hospital, Baroda, had clean as well as infected wound following trauma, debridement, pressure sore, venous ulcer, and incision and drainage. Wound surface areas were measured by these three methods (linear, transparency, and photographic methods) simultaneously on alternate days. The linear method is statistically and significantly different from transparency and photographic methods (P value transparency and photographic methods (P value >0.05). Photographic and transparency methods provided measurements of wound surface area with equivalent result and there was no statistically significant difference between these two methods.

  13. Silver-mediated base pairings: towards dynamic DNA nanostructures with enhanced chemical and thermal stability

    International Nuclear Information System (INIS)

    Swasey, Steven M; Gwinn, Elisabeth G

    2016-01-01

    The thermal and chemical fragility of DNA nanomaterials assembled by Watson–Crick (WC) pairing constrain the settings in which these materials can be used and how they can be functionalized. Here we investigate use of the silver cation, Ag + , as an agent for more robust, metal-mediated self-assembly, focusing on the simplest duplex building blocks that would be required for more elaborate Ag + –DNA nanostructures. Our studies of Ag + -induced assembly of non-complementary DNA oligomers employ strands of 2–24 bases, with varied base compositions, and use electrospray ionization mass spectrometry to determine product compositions. High yields of duplex products containing narrowly distributed numbers of Ag + can be achieved by optimizing solution conditions. These Ag + -mediated duplexes are stable to at least 60 mM Mg 2+ , higher than is necessary for WC nanotechnology schemes such as tile assemblies and DNA origami, indicating that sequential stages of Ag + -mediated and WC-mediated assembly may be feasible. Circular dichroism spectroscopy suggests simple helical structures for Ag + -mediated duplexes with lengths to at least 20 base pairs, and further indicates that the structure of cytosine-rich duplexes is preserved at high urea concentrations. We therefore propose an approach towards dynamic DNA nanomaterials with enhanced thermal and chemical stability through designs that combine sturdy silver-mediated ‘frames’ with WC paired ‘pictures’. (paper)

  14. Removal of mercury vapor from ambient air of dental clinics using an air cleaning system based on silver nanoparticles

    Directory of Open Access Journals (Sweden)

    Chiman Saeidi

    2015-06-01

    Full Text Available Background & objective: Mercury is a toxic and bio-accumulative pollutant that has adverse effects on environmental and human health. There have been a number of attempts to regulate mercury emissions tothe atmosphere. Silver nanoparticles are a number of materials that have highly potential to absorb mercury and formation of mercury amalgam.The aim of this study is removal of mercury vapors in the dental clinic using a n a ir cleaning system based on silver nanoparticles. Methods: In this study, silver nanoparticles coated on the bed of foam and chemical and structural properties were determined using a number of methods such as UV-VIS-NIR spectroscopy and Scanning Electron Microscope (SEM connected the X-ray Emission Spectroscopy Energy (EDS. The a ir cleaning system efficiency to remove of the mercury vapor in simulated conditions in the laboratory and real conditions in the dental clinicwere measured by Cold Vapor Atomic Absorption Spectroscopy (CVAAS. Results: The images of SEM, showed that average sizeof silver nanoparticles in colloidal solution was ∼ 30nm and distribution of silver nanoparticles coated on foam was good. EDS spectrum confirmed associated the presence of silver nanoparticles coated on foam. The significantly difference observed between the concentration of mercury vapor in the off state (9.43 ± 0.342 μg.m-3 and on state (0.51 ± 0.031μg.m-3 of the a ir cleaning system. The mercury vapor removal efficiencyof the a ir cleaning system was calculated 95%. Conclusion : The air cleaning system based on foam coated by silver nanoparticles, undertaken to provide the advantages such as use facilitating, highly efficient operational capacity and cost effective, have highly sufficiency to remove mercury vapor from dental clinics.

  15. Quaternized Carboxymethyl Chitosan-Based Silver Nanoparticles Hybrid: Microwave-Assisted Synthesis, Characterization and Antibacterial Activity

    Directory of Open Access Journals (Sweden)

    Siqi Huang

    2016-06-01

    Full Text Available A facile, efficient, and eco-friendly approach for the preparation of uniform silver nanoparticles (Ag NPs was developed. The synthesis was conducted in an aqueous medium exposed to microwave irradiation for 8 min, using laboratory-prepared, water-soluble quaternized carboxymethyl chitosan (QCMC as a chemical reducer and stabilizer and silver nitrate as the silver source. The structure of the prepared QCMC was characterized using Fourier transform infrared (FT-IR and 1H nuclear magnetic resonance (NMR. The formation, size distribution, and dispersion of the Ag NPs in the QCMC matrix were determined using X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, ultraviolet-visible (UV-Vis, transmission electron microscopy (TEM, and field emission scanning electron microscope (FESEM analysis, and the thermal stability and antibacterial properties of the synthesized QCMC-based Ag NPs composite (QCMC-Ag were also explored. The results revealed that (1 QCMC was successfully prepared by grafting quaternary ammonium groups onto carboxymethyl chitosan (CMC chains under microwave irradiation in water for 90 min and this substitution appeared to have occurred at -NH2 sites on C2 position of the pyranoid ring; (2 uniform and stable spherical Ag NPs could be synthesized when QCMC was used as the reducing and stabilizing agent; (3 Ag NPs were well dispersed in the QCMC matrix with a narrow size distribiution in the range of 17–31 nm without aggregation; and (4 due to the presence of Ag NPs, the thermal stability and antibacterial activity of QCMC-Ag were dramatically improved relative to QCMC.

  16. Quaternized Carboxymethyl Chitosan-Based Silver Nanoparticles Hybrid: Microwave-Assisted Synthesis, Characterization and Antibacterial Activity.

    Science.gov (United States)

    Huang, Siqi; Wang, Jing; Zhang, Yang; Yu, Zhiming; Qi, Chusheng

    2016-06-17

    A facile, efficient, and eco-friendly approach for the preparation of uniform silver nanoparticles (Ag NPs) was developed. The synthesis was conducted in an aqueous medium exposed to microwave irradiation for 8 min, using laboratory-prepared, water-soluble quaternized carboxymethyl chitosan (QCMC) as a chemical reducer and stabilizer and silver nitrate as the silver source. The structure of the prepared QCMC was characterized using Fourier transform infrared (FT-IR) and ¹H nuclear magnetic resonance (NMR). The formation, size distribution, and dispersion of the Ag NPs in the QCMC matrix were determined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible (UV-Vis), transmission electron microscopy (TEM), and field emission scanning electron microscope (FESEM) analysis, and the thermal stability and antibacterial properties of the synthesized QCMC-based Ag NPs composite (QCMC-Ag) were also explored. The results revealed that (1) QCMC was successfully prepared by grafting quaternary ammonium groups onto carboxymethyl chitosan (CMC) chains under microwave irradiation in water for 90 min and this substitution appeared to have occurred at -NH₂ sites on C2 position of the pyranoid ring; (2) uniform and stable spherical Ag NPs could be synthesized when QCMC was used as the reducing and stabilizing agent; (3) Ag NPs were well dispersed in the QCMC matrix with a narrow size distribiution in the range of 17-31 nm without aggregation; and (4) due to the presence of Ag NPs, the thermal stability and antibacterial activity of QCMC-Ag were dramatically improved relative to QCMC.

  17. Plasmonic 3D-structures based on silver decorated nanotips for biological sensing

    Science.gov (United States)

    Coluccio, M. L.; Francardi, M.; Gentile, F.; Candeloro, P.; Ferrara, L.; Perozziello, G.; Di Fabrizio, E.

    2016-01-01

    Recent progresses in nanotechnology fabrication gives the opportunity to build highly functional nano-devices. 3D structures based on noble metals or covered by them can be realized down to the nano-scales, obtaining different devices with the functionalities of plasmonic nano-lenses or nano-probes. Here, nano-cones decorated with silver nano-grains were fabricated using advanced nano-fabrication techniques. In fabricating the cones, the angle of the apex was varied over a significant range and, in doing so, different geometries were realized. In depositing the silver nano-particles, the concentration of solution was varied, whereby different growth conditions were realized. The combined effect of tip geometry and growth conditions influences the size and distribution of the silver nano grains. The tips have the ability to guide or control the growth of the grains, in the sense that the nano-particles would preferentially distribute along the cone, and especially at the apex of the cone, with no o minor concentration effects on the substrate. The arrangement of metallic nano-particles into three-dimensional (3D) structures results in a Surface Enhanced Raman Spectroscopy (SERS) device with improved interface with analytes compared to bi-dimensional arrays of metallic nanoparticles. In the future, similar devices may find application in microfluidic devices, and in general in flow chambers, where the system can be inserted as to mimic a a nano-bait, for the recognition of specific biomarkers, or the manipulation and chemical investigation of single cells directly in native environments with good sensitivity, repeatability and selectivity.

  18. A competitive immunoassay for sensitive detection of small molecules chloramphenicol based on luminol functionalized silver nanoprobe.

    Science.gov (United States)

    Yu, Xiuxia; He, Yi; Jiang, Jie; Cui, Hua

    2014-02-17

    Chloramphenicol (CHL) as a broad-spectrum antibiotic has a broad action spectrum against Gram-positive and Gram-negative bacteria, as well as anaerobes. The use of CHL is strictly restricted in poultry because of its toxic effect. However, CHL is still illegally used in animal farming because of its accessibility and low cost. Therefore, sensitive methods are highly desired for the determination of CHL in foodstuffs. The immunoassays based on labeling as an important tool have been reported for the detection of CHL residues in food-producing animals. However, most of the labeling procedures require multi-step reactions and purifications and thus they are complicated and time-consuming. Recently, in our previous work, luminol functionalized silver nanoparticles have been successfully synthesized, which exhibits higher CL efficiency than luminol functionalized gold nanoparticles. In this work, the new luminol functionalized silver nanoparticles have been used for the labeling of small molecules CHL for the first time and a competitive chemiluminescent immunoassay has been developed for the detection of CHL. Owing to the amplification of silver nanoparticles, high sensitivity for CHL could be achieved with a low detection limit of 7.6×10(-9) g mL(-1) and a wide linear dynamic range of 1.0×10(-8)-1.0×10(-6) g mL(-1). This method has also been successfully applied to determine CHL in milk and honey samples with a good recoveries (92% and 102%, 99% and 107% respectively), indicating that the method is feasible for the determination of CHL in real milk and honey samples. The labeling procedure is simple, convenient and fast, superior to previously reported labeling procedures. The immunoassay is also simple, fast, sensitive and selective. It is of application potential for the determination of CHL in foodstuffs. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Structural properties of silver nanoparticle agglomerates based on transmission electron microscopy: relationship to particle mobility analysis

    International Nuclear Information System (INIS)

    Shin, Weon Gyu; Wang Jing; Mertler, Michael; Sachweh, Bernd; Fissan, Heinz; Pui, David Y. H.

    2009-01-01

    In this work, the structural properties of silver nanoparticle agglomerates generated using condensation and evaporation method in an electric tube furnace followed by a coagulation process are analyzed using Transmission Electron Microscopy (TEM). Agglomerates with mobility diameters of 80, 120, and 150 nm are sampled using the electrostatic method and then imaged by TEM. The primary particle diameter of silver agglomerates was 13.8 nm with a standard deviation of 2.5 nm. We obtained the relationship between the projected area equivalent diameter (d pa ) and the mobility diameter (d m ), i.e., d pa = 0.92 ± 0.03 d m for particles from 80 to 150 nm. We obtained fractal dimensions of silver agglomerates using three different methods: (1) D f = 1.84 ± 0.03, 1.75 ± 0.06, and 1.74 ± 0.03 for d m = 80, 120, and 150 nm, respectively from projected TEM images using a box counting algorithm; (2) fractal dimension (D fL ) = 1.47 based on maximum projected length from projected TEM images using an empirical equation proposed by Koylu et al. (1995) Combust Flame 100:621-633; and (3) mass fractal-like dimension (D fm ) = 1.71 theoretically derived from the mobility analysis proposed by Lall and Friedlander (2006) J Aerosol Sci 37:260-271. We also compared the number of primary particles in agglomerate and found that the number of primary particles obtained from the projected surface area using an empirical equation proposed by Koylu et al. (1995) Combust Flame 100:621-633 is larger than that from using the relationship, d pa = 0.92 ± 0.03 d m or from using the mobility analysis.

  20. Plasmonic 3D-structures based on silver decorated nanotips for biological sensing

    KAUST Repository

    Coluccio, M. L.

    2015-05-01

    Recent progresses in nanotechnology fabrication gives the opportunity to build highly functional nano-devices. 3D structures based on noble metals or covered by them can be realized down to the nano-scales, obtaining different devices with the functionalities of plasmonic nano-lenses or nano-probes. Here, nano-cones decorated with silver nano-grains were fabricated using advanced nano-fabrication techniques. In fabricating the cones, the angle of the apex was varied over a significant range and, in doing so, different geometries were realized. In depositing the silver nano-particles, the concentration of solution was varied, whereby different growth conditions were realized. The combined effect of tip geometry and growth conditions influences the size and distribution of the silver nano grains. The tips have the ability to guide or control the growth of the grains, in the sense that the nano-particles would preferentially distribute along the cone, and especially at the apex of the cone, with no o minor concentration effects on the substrate. The arrangement of metallic nano-particles into three-dimensional (3D) structures results in a Surface Enhanced Raman Spectroscopy (SERS) device with improved interface with analytes compared to bi-dimensional arrays of metallic nanoparticles. In the future, similar devices may find application in microfluidic devices, and in general in flow chambers, where the system can be inserted as to mimic a a nano-bait, for the recognition of specific biomarkers, or the manipulation and chemical investigation of single cells directly in native environments with good sensitivity, repeatability and selectivity. © 2015 Elsevier Ltd.

  1. Progress in UCO's search for silver-based telescope mirror coatings

    Science.gov (United States)

    Phillips, Andrew C.; Miller, Joseph S.; Bolte, Michael; DuPraw, Brian; Radovan, Matthew; Cowley, David

    2012-09-01

    We report on the on-going effort at University of California Observatories Astronomical Coatings Lab to develop robust protected-silver coatings suitable for telescope mirrors. We have identified a very promising recipe based on YF3 that produces excellent reflectivity at wavelengths of 340 nm and greater, has ~1.5% emissivity in the thermal IR, and does not contain problematic materials for the Mid-IR, such as SiO2 and Al2O3. The recipe holds up extremely well to aggressive environmental testing (80C and 80% RH; high-H2S atmosphere), and currently is being evaluated under real observatory conditions. This coating may satisfy the need for telescope mirror coatings that are long-lasting (~5 years or more) and have good reflectivity into the UV. We also evaluate and compare some other silver-based coatings developed elsewhere that should be useful in the same role. In addition, we describe recent upgrades to our coating facilities allowing us to deposit ion-assisted e-beam coatings on optics up to ~1m. This novel arrangement places the e-gun and ion source on a pivoting "swing-arm", allowing the position to move radially without changing the e-gun/ion source/ substrate geometry. Large substrates can be coated with good uniformity using single-axis rotation only. This technique is scalable to arbitrarily large substrate sizes.

  2. Schiff Base modified on CPE electrode and PCB gold electrode for selective determination of silver ion

    Science.gov (United States)

    Leepheng, Piyawan; Suramitr, Songwut; Phromyothin, Darinee

    2017-09-01

    The schiff base was synthesized by 2,5-thiophenedicarboxaldehyde and 1,2,4-thiadiazole-3,5-diamine with condensation method. There was modified on carbon paste electrode (CPE) and Printed circuit board (PCB) gold electrode for determination silver ion. The schiff base modified electrodes was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The electrochemical study was reported by cyclic voltammetry method and impedance spectroscopy using modified electrode as working electrode, platinum wire and Ag/AgCl as counter electrode and reference electrode, respectively. The modified electrodes have suitable detection for Ag+. The determination of silver ions using the modified electrodes depended linearly on Ag+ concentration in the range 1×10-10 M to 1×10-7 M, with cyclic voltammetry sensitivity were 2.51×108 μAM-1 and 1.88×108 μAM-1 for PCB gold electrode and CPE electrode, respectively, limits of detection were 5.33×10-9 M and 1.99×10-8 M for PCB gold electrode and CPE electrode, respectively. The modified electrodes have high accuracy, inexpensive and can applied to detection Ag+ in real samples.

  3. Aescin-based topical formulation to prevent foot wounds and ulcerations in diabetic microangiopathy.

    Science.gov (United States)

    Hu, S; Belcaro, G; Dugall, M; Hosoi, M; Togni, S; Maramaldi, G; Giacomelli, L

    2016-10-01

    Impairment of the peripheral microcirculation in diabetic patients often leads to severe complications in the lower extremities, such as foot infections and ulcerations. In this study, a novel aescin-based formulation has been evaluated as a potential approach to prevent skin breaks and ulcerations by improving the peripheral microcirculation and skin hydration. In this registry study, 63 patients with moderate diabetic microangiopathy were recruited. Informed participants freely decided to follow either a standard management (SM) to prevent diabetic foot diseases (n = 31) or SM associated with topical application of the aescin-based cream (n = 32). Peripheral microcirculatory parameters such as resting skin flux, venoarteriolar response and transcutaneous gas tension were evaluated at inclusion and after 8 weeks. In addition, several skin parameters of the foot area, such as integrity (as number of skin breaks/patients), hydration and content of dead cells were assessed at the defined observational study periods. Improvements in cutaneous peripheral microcirculation parameters were observed at 8 weeks in both groups; however, a remarkable and significant beneficial effect resulted to be exerted by the aescin-based cream treatment. In fact, the microcirculatory parameters evaluated significantly improved in the standard management + aescin-based cream group, compared with baseline and with the standard management group. Similar findings were reported for skin parameters of the foot area. The topical formulation containing aescin could represent a valid approach to manage skin wounds and prevent skin ulcerations in patients affected by moderate diabetic microangiopathy.

  4. A silver ion-doped calcium phosphate-based ceramic nanopowder-coated prosthesis increased infection resistance.

    Science.gov (United States)

    Kose, Nusret; Otuzbir, Ali; Pekşen, Ceren; Kiremitçi, Abdurrahman; Doğan, Aydin

    2013-08-01

    Despite progress in surgical techniques, 1% to 2% of joint arthroplasties become complicated by infection. Coating implant surfaces with antimicrobial agents have been attempted to prevent initial bacterial adhesion to implants with varying success rates. We developed a silver ion-containing calcium phosphate-based ceramic nanopowder coating to provide antibacterial activity for orthopaedic implants. We asked whether titanium prostheses coated with this nanopowder would show resistance to bacterial colonization as compared with uncoated prostheses. We inserted titanium implants (uncoated [n = 9], hydroxyapatite-coated [n = 9], silver-coated [n = 9]) simulating knee prostheses into 27 rabbits' knees. Before implantation, 5 × 10(2) colony-forming units of Staphylococcus aureus were inoculated into the femoral canal. Radiology, microbiology, and histology findings were quantified at Week 6 to define the infection, microbiologically by increased rate of implant colonization/positive cultures, histologically by leukocyte infiltration, necrosis, foreign-body granuloma, and devitalized bone, and radiographically by periosteal reaction, osteolysis, or sequestrum formation. Swab samples taken from medullary canals and implants revealed a lower proportion of positive culture in silver-coated implants (one of nine) than in uncoated (eight of nine) or hydroxyapatite-coated (five of nine) implants. Silver-coated implants also had a lower rate of colonization. No cellular inflammation or foreign-body granuloma was observed around the silver-coated prostheses. Silver ion-doped ceramic nanopowder coating of titanium implants led to an increase in resistance to bacterial colonization compared to uncoated implants. Silver-coated orthopaedic implants may be useful for resistance to local infection but will require in vivo confirmation.

  5. A Chitosan—Based Liposome Formulation Enhances the In Vitro Wound Healing Efficacy of Substance P Neuropeptide

    Directory of Open Access Journals (Sweden)

    Tamara Mengoni

    2017-12-01

    Full Text Available Currently, there is considerable interest in developing innovative biodegradable nanoformulations for controlled administration of therapeutic proteins and peptides. Substance P (SP is a neuropeptide of 11 amino acids that belongs to the tachykinins family and it plays an important role in wound healing. However, SP is easily degradable in vivo and has a very short half-life, so the use of chitosan-based nanocarriers could enhance its pharmaceutical properties. In light of the above, the aim of this work was to produce and characterize chitosan-coated liposomes loaded with SP (SP-CH-LP as novel biomaterials with potential application in mucosal wound healing. The loaded system’s biophysical properties were characterized by dynamic light scattering with non-invasive back scattering (DLS-NIBS, mixed mode measurements and phase analysis light scattering (M3-PALS and high performance liquid chromatography with ultraviolet/visible light detection (HPLC-UV/VIS. Then, the efficacy of the obtained nanoformulations was examined via proof-of-principle experiments using in vitro cell assays. These assays showed an increment on cell motility and proliferation after treatment with free and encapsulated neuropeptides. Additionally, the effect of SP on wound healing was enhanced by the entrapment on CH-LP. Overall, the amenability of chitosan-based nanomaterials to encapsulate peptides and proteins constitutes a promising approach towards potential novel therapies to treat difficult wounds.

  6. Colorimetric detection of trace copper ions based on catalytic leaching of silver-coated gold nanoparticles.

    Science.gov (United States)

    Lou, Tingting; Chen, Lingxin; Chen, Zhaopeng; Wang, Yunqing; Chen, Ling; Li, Jinhua

    2011-11-01

    A colorimetric, label-free, and nonaggregation-based silver coated gold nanoparticles (Ag/Au NPs) probe has been developed for detection of trace Cu(2+) in aqueous solution, based on the fact that Cu(2+) can accelerate the leaching rate of Ag/Au NPs by thiosulfate (S(2)O(3)(2-)). The leaching of Ag/Au NPs would lead to dramatic decrease in the surface plasmon resonance (SPR) absorption as the size of Ag/Au NPs decreased. This colorimetric strategy based on size-dependence of nanoparticles during their leaching process provided a highly sensitive (1.0 nM) and selective detection toward Cu(2+), with a wide linear detection range (5-800 nM) over nearly 3 orders of magnitude. The cost-effective probe allows rapid and sensitive detection of trace Cu(2+) ions in water samples, indicating its potential applicability for the determination of copper in real samples.

  7. Light-based therapy on wound healing : a review

    International Nuclear Information System (INIS)

    Suan, Lau Pik; Bidin, Noriah; Cherng, Chong Jia; Hamid, Asmah

    2014-01-01

    Wound healing is a complex matrix and overlapping process. In order to accelerate the healing process and minimize bacterial infection, light-based therapy was applied to stimulate bio-reaction to improve healing. The aim of this paper is to review the effects induced by light source (laser and incoherent light like LED) on different biological targets. The light-based therapy techniques were categorized according to the wavelength, energy density, type of irradiance and activity of tissues in the healing process. Out of 80 cases, 77% were animal studies, 5% were human studies and 18% were cell studies. Around 75% of light-based therapy has an advantage on tissue interaction and 25% has no effect or inhibition on the healing process. The appropriate dose appears to be between 1 and 5 J cm −2 . At shorter wavelength, photobiostimulation would be effective with a high frequently administrated low-energy dose. On the other hand, for longer wavelength it is the reverse, i.e., more effective with a low frequent treated schedule and a high-energy dose. (topical reviews)

  8. A data-based technique for monitoring of wound rotor induction machines: A simulation study

    KAUST Repository

    Harrou, Fouzi

    2016-05-09

    Detecting faults induction machines is crucial for a safe operation of these machines. The aim of this paper is to present a statistical fault detection methodology for the detection of faults in three-phase wound rotor induction machines (WRIM). The proposed fault detection approach is based on the use of principal components analysis (PCA). However, conventional PCA-based detection indices, such as the T2T2 and the Q statistics, are not well suited to detect small faults because these indices only use information from the most recent available samples. Detection of small faults is one of the most crucial and challenging tasks in the area of fault detection and diagnosis. In this paper, a new statistical system monitoring strategy is proposed for detecting changes resulting from small shifts in several variables associated with WRIM. The proposed approach combines modeling using PCA modeling with the exponentially weighted moving average (EWMA) control scheme. In the proposed approach, EWMA control scheme is applied on the ignored principal components to detect the presence of faults. The performance of the proposed method is compared with those of the traditional PCA-based fault detection indices. The simulation results clearly show the effectiveness of the proposed method over the conventional ones, especially in the presence of faults with small magnitudes.

  9. Simulation, Fabrication and Analysis of Silver Based Ascending Sinusoidal Microchannel (ASMC for Implant of Varicose Veins

    Directory of Open Access Journals (Sweden)

    Muhammad Javaid Afzal

    2017-09-01

    Full Text Available Bioengineered veins can benefit humans needing bypass surgery, dialysis, and now, in the treatment of varicose veins. The implant of this vein in varicose veins has significant advantages over the conventional treatment methods. Deep vein thrombosis (DVT, vein patch repair, pulmonary embolus, and tissue-damaging problems can be solved with this implant. Here, the authors have proposed biomedical microdevices as an alternative for varicose veins. MATLAB and ANSYS Fluent have been used for simulations of blood flow for bioengineered veins. The silver based microchannel has been fabricated by using a micromachining process. The dimensions of the silver substrates are 51 mm, 25 mm, and 1.1 mm, in length, width, and depth respectively. The dimensions of microchannels grooved in the substrates are 0.9 mm in width and depth. The boundary conditions for pressure and velocity were considered, from 1.0 kPa to 1.50 kPa, and 0.02 m/s to 0.07 m/s, respectively. These are the actual values of pressure and velocity in varicose veins. The flow rate of 5.843 (0.1 nL/s and velocity of 5.843 cm/s were determined at Reynolds number 164.88 in experimental testing. The graphs and results from simulations and experiments are in close agreement. These microchannels can be inserted into varicose veins as a replacement to maintain the excellent blood flow in human legs.

  10. Bendable transparent conductive meshes based on multi-layer inkjet-printed silver patterns

    International Nuclear Information System (INIS)

    Yu, Po-Chin; Hong, Chien-Chong; Liou, Tong-Miin

    2016-01-01

    Many consumer electronics manufacturers have used transparent conductive films in solar cells, LED devices, and touch panels as a medium for simultaneous electric charge transportation and light transmission. The conductivity and transmittance of transparent conductive films greatly affect the efficiency of these optoelectronic devices. This study presents a transparent and conductive mesh based on inkjet-printed silver and conductive polymer. Also, we propose a mathematical model for calculating the optimized mesh pattern. The proposed model precisely calculates an optimized line-width-to-line-spacing ratio. Furthermore, the results of our experiment verify the relationship between the line-width-to-line-spacing ratio and figure of merit. Compared with the equations of past studies, the equation proposed in this study is valid for a broader range of line-width-to-line-spacing ratios. In addition, the theoretical results of our study correlate more strongly with the experimental data of this study than with that of previous studies. To achieve the highest figure of merit, the values of the filling factor and the line-width-to-line-spacing ratio should be 0.05 and 19, respectively. Finally, we reduced the sheet resistance of the inkjet-printed mesh by 97.9% by applying multilayer printing. However, we were able to reduce only the optical transmittance of the mesh by 3.0%. The developed inkjet-printed silver meshes can survive more than 3500 bending tests simultaneous with application of 300 mA current. (paper)

  11. Transport and dielectric studies on silver based molybdo-tungstate quaternary superionic conducting glasses

    International Nuclear Information System (INIS)

    Prasad, P.S.S.; Radhakrishna, S.

    1988-01-01

    The molybdo-tungstate (MoO 3 -WO 3 ) combination of glass formers with silver oxide (Ag 2 O) as glass modifier and silver iodide (AgI) as ionic conductor were prepared to study the transport and dielectric properties of 60% AgI-40% (x Ag 2 O-y(WO 3 -MoO 3 )) for x/y=0.33 to 3.0 and establish the feasibility of using these glasses as electrolytes in the fabrication and characterisation of solid state batteries and potential memory devices. The details of the preparation of glasses and methods of measurement of their capacitance, dielectric loss factor and ac conductivity in the frequency range 100 Hz - 100 kHz from 30-120 C have been reported. The electronic contribution to the total conductivity, the ionic and electronic transport numbers were determined using Wagners dc polarisation technique. The observed high ionic and low electronic conductivities were attributed to the formation of ionic clusters in the glass and the effect of mixing two glass formers. The observed total ionic conductivity and its temperature dependence was explained using Arrhenius relation σ=σ 0 /T exp(-E/RT) and the measured dielectric constant and dielectric loss were explained on the basis of Jonschers theory. The frequency dependence of dielectric constant obeys the theory based on the polarisation of ions. 25 refs.; 8 figs

  12. Characterization of the silver coins of the Hoard of Beçin by X-ray based methods

    Science.gov (United States)

    Rodrigues, M.; Schreiner, M.; Melcher, M.; Guerra, M.; Salomon, J.; Radtke, M.; Alram, M.; Schindel, N.

    2011-12-01

    Four hundred sixteen silver coins stemming from the Ottoman Empire (16th and 17th centuries) were analyzed in order to confirm the fineness of the coinage as well as to study the provenance of the alloy used for the coins. As most of the coins showed the typical green patina on their surfaces due to corrosion processes which have led to the depletion of copper in the near-surface domains of the silver coins in comparison to their core composition, small samples by cutting splinters from the coins had to be taken, embedded in synthetic resin and cross-sectioned in order to investigate the true-heart metal composition. The type of the alloy was investigated as well as if coins minted in different locations demonstrated homogeneous traits concerning the predominant impurities which could suggest a common ore. Several X-ray based techniques (μ-XRF, μ-SRXRF and μ-PIXE) could be applied in order to determine the silver contents as well as the minor and trace elements. Finally, SEM/EDX was applied in order to study the homogeneity/heterogeneity of the coins and the presence of surface enrichments. In general, the silver content of the analyzed specimen varies between 90% and 95%. These outcomes have not supported the historical interpretations, which predict that during the period studied a debasement of approximately 44% of the silver content of the coins should have occurred.

  13. Characterization of the silver coins of the Hoard of Beçin by X-ray based methods

    International Nuclear Information System (INIS)

    Rodrigues, M.; Schreiner, M.; Melcher, M.; Guerra, M.; Salomon, J.; Radtke, M.; Alram, M.; Schindel, N.

    2011-01-01

    Four hundred sixteen silver coins stemming from the Ottoman Empire (16th and 17th centuries) were analyzed in order to confirm the fineness of the coinage as well as to study the provenance of the alloy used for the coins. As most of the coins showed the typical green patina on their surfaces due to corrosion processes which have led to the depletion of copper in the near-surface domains of the silver coins in comparison to their core composition, small samples by cutting splinters from the coins had to be taken, embedded in synthetic resin and cross-sectioned in order to investigate the true-heart metal composition. The type of the alloy was investigated as well as if coins minted in different locations demonstrated homogeneous traits concerning the predominant impurities which could suggest a common ore. Several X-ray based techniques (μ-XRF, μ-SRXRF and μ-PIXE) could be applied in order to determine the silver contents as well as the minor and trace elements. Finally, SEM/EDX was applied in order to study the homogeneity/heterogeneity of the coins and the presence of surface enrichments. In general, the silver content of the analyzed specimen varies between 90% and 95%. These outcomes have not supported the historical interpretations, which predict that during the period studied a debasement of approximately 44% of the silver content of the coins should have occurred.

  14. A data-based technique for monitoring of wound rotor induction machines: A simulation study

    KAUST Repository

    Harrou, Fouzi; Ramahaleomiarantsoa, Jacques F.; Nounou, Mohamed N.; Nounou, Hazem N.

    2016-01-01

    Detecting faults induction machines is crucial for a safe operation of these machines. The aim of this paper is to present a statistical fault detection methodology for the detection of faults in three-phase wound rotor induction machines (WRIM

  15. Development and Characterization of Novel Films Based on Sulfonamide-Chitosan Derivatives for Potential Wound Dressing

    Directory of Open Access Journals (Sweden)

    Oana Maria Dragostin

    2015-12-01

    Full Text Available The objective of this study was to develop new films based on chitosan functionalized with sulfonamide drugs (sulfametoxydiazine, sulfadiazine, sulfadimetho-xine, sulfamethoxazol, sulfamerazine, sulfizoxazol in order to enhance the biological effects of chitosan. The morphology and physical properties of functionalized chitosan films as well the antioxidant effects of sulfonamide-chitosan derivatives were investigated. The chitosan-derivative films showed a rough surface and hydrophilic properties, which are very important features for their use as a wound dressing. The film based on chitosan-sulfisoxazol (CS-S6 showed the highest swelling ratio (197% and the highest biodegradation rate (63.04% in comparison to chitosan film for which the swelling ratio was 190% and biodegradation rate was only 10%. Referring to the antioxidant effects the most active was chitosan-sulfamerazine (CS-S5 which was 8.3 times more active than chitosan related to DPPH (1,1-diphenyl-2-picrylhydrazyl radical scavenging ability. This compound showed also a good ferric reducing power and improved total antioxidant capacity.

  16. Optical Fiber Sensor Based on Localized Surface Plasmon Resonance Using Silver Nanoparticles Photodeposited on the Optical Fiber End

    Directory of Open Access Journals (Sweden)

    J. Gabriel Ortega-Mendoza

    2014-10-01

    Full Text Available This paper reports the implementation of an optical fiber sensor to measure the refractive index in aqueous media based on localized surface plasmon resonance (LSPR. We have used a novel technique known as photodeposition to immobilize silver nanoparticles on the optical fiber end. This technique has a simple instrumentation, involves laser light via an optical fiber and silver nanoparticles suspended in an aqueous medium. The optical sensor was assembled using a tungsten lamp as white light, a spectrometer, and an optical fiber with silver nanoparticles. The response of this sensor is such that the LSPR peak wavelength is linearly shifted to longer wavelengths as the refractive index is increased, showing a sensitivity of 67.6 nm/RIU. Experimental results are presented.

  17. Tunable strain gauges based on two-dimensional silver nanowire networks

    International Nuclear Information System (INIS)

    Ho, Xinning; Cheng, Chek Kweng; Tey, Ju Nie; Wei, Jun

    2015-01-01

    Strain gauges are used in various applications such as wearable strain gauges and strain gauges in airplanes or structural health monitoring. Sensitivity of the strain gauge required varies, depending on the application of the strain gauge. This paper reports a tunable strain gauge based on a two-dimensional percolative network of silver nanowires. By varying the surface coverage of the nanowire network and the waviness of the nanowires in the network, the sensitivity of the strain gauge can be controlled. Hence, a tunable strain gauge can be engineered, based on demands of the application. A few applications are demonstrated. The strain gauge can be adhered to the human neck to detect throat movements and a glove integrated with such a strain gauge can detect the bending of the forefinger. Other classes of two-dimensional percolative networks of one-dimensional materials are also expected to exhibit similar tunable properties. (paper)

  18. Preparation and Properties of Silver Nanowire-Based Transparent Conductive Composite Films

    Science.gov (United States)

    Tian, Ji-Li; Zhang, Hua-Yu; Wang, Hai-Jun

    2016-06-01

    Silver nanowire-based transparent conductive composite films with different structures were successfully prepared using various methods, including liquid polyol, magnetron sputtering and spin coating. The experimental results revealed that the optical transmittance of all different structural composite films decreased slightly (1-3%) compared to pure films. However, the electrical conductivity of all composite films had a great improvement. Under the condition that the optical transmittance was greater than 78% over the wavelength range of 400-800 nm, the AgNW/PVA/AgNW film became a conductor, while the AZO/AgNW/AZO film and the ITO/AgNW/ITO film showed 88.9% and 94% reductions, respectively, for the sheet resistance compared with pure films. In addition, applying a suitable mechanical pressure can improve the conductivity of AgNW-based composite films.

  19. Antimicrobial activity of silver nanoparticles encapsulated in poly-N-isopropylacrylamide-based polymeric nanoparticles.

    Science.gov (United States)

    Qasim, Muhammad; Udomluck, Nopphadol; Chang, Jihyun; Park, Hansoo; Kim, Kyobum

    2018-01-01

    In this study, we analyzed the antimicrobial activities of poly- N -isopropylacrylamide (pNIPAM)-based polymeric nanoparticles encapsulating silver nanoparticles (AgNPs). Three sizes of AgNP-encapsulating pNIPAM- and pNIPAM-NH 2 -based polymeric nanoparticles were fabricated. Highly stable and uniformly distributed AgNPs were encapsulated within polymeric nanoparticles via in situ reduction of AgNO 3 using NaBH 4 as the reducing agent. The formation and distribution of AgNPs was confirmed by UV-visible spectroscopy, transmission electron microscopy, and inductively coupled plasma optical emission spectrometry, respectively. Both polymeric nanoparticles showed significant bacteriostatic activities against Gram-negative ( Escherichia coli ) and Gram-positive ( Staphylococcus aureus ) bacteria depending on the nanoparticle size and amount of AgNO 3 used during fabrication.

  20. Determination of dextrose in peritoneal dialysis solution by localized surface plasmon resonance technique based on silver nanoparticles formation

    Science.gov (United States)

    Masrournia, Mahboube; Montazarolmahdi, Maliheh; Sani, Faramarz Aliasghari

    2017-07-01

    Determination of dextrose in peritoneal dialysis with a method based on silver nanoparticles (AgNPs) formation was investigated. In a green chemistry method, silver nanoparticles (AgNPs) were synthesized in the natural polymeric matrix of gelatin. The nanoparticles were characterized with UV-Vis spectroscopy and transmission electron microscopy (TEM). Absorbance signal of AgNPs could be applied to determine the various concentrations of dextrose solutions. Drop wise and ultrasonic methods were used and compared with each other. The dynamic range of methods with limit of detection and relative standard deviations were obtained. Results for real sample (peritoneal dialysis) were satisfied.

  1. Distal Based Sural Fascio-Cutaneous Flap: A Practical Limb Saviour for Wounds of War and Peace

    International Nuclear Information System (INIS)

    Tahirkheli, M. U. I.; Ellahi, I.; Dar, M. F.; Sharif, A.

    2016-01-01

    Objective: To determine the effect of mechanism of injury on wound healing, and on the viability and success of distally based sural flap when used for the coverage of defects of lower leg, ankle and foot. Study Design: Descriptive study. Place and Duration of Study: Department of Surgery, Combined Military Hospital, Peshawar and Khariyan, from January 2012 to December 2014. Methodology: Patients with soft tissue defects over the distal leg, ankle and foot were selected by purposive sampling technique and divided into 2 groups of 19 patients each. Group A(road traffic accidents) and group B (war injuries). Sural fascio-cutaneous flap was the reconstructive tool used in all the cases using single technique by the same surgical team; and time for recipient site preparation, size of the defect, graft survival, its healing time and complications, were studied. Result: The mean age of the 38 patients in the study was 28.2 ±13.4 years. There were 36 male and 2 female patients. The most common site of injury encountered was leg (n=20) followed by foot (n=11) and ankle (n=5). Maximum wound size seen in group A was 10 x 12 cm and in group B was 15 x 38 cm. Recovery was uneventful in 17/19 cases of group Awhile 7/19 in group B and with no graft failure. Superficial epidermolysis was seen in 2 and 8 cases in group A and B respectively while edge necrosis of the flap was observed in group B only (n=4). Healing time on average was 2 to 3 weeks in group A, and 4 to 5 weeks in group B. Conclusion: Soft tissue defects of the distal lower extremity as a result of war injuries and road traffic accidents have different dynamics in terms of wound size, time of wound healing, wound complications and functional outcome; but distal based sural flap has promising Result in both situations. (author)

  2. TTC- Based Test as an Efficient Method to Determine Antibiofilm Activity of Silver Nanoparticles

    OpenAIRE

    Chojniak Joanna; Biedroń Izabela; Płaza Grażyna

    2017-01-01

    Among metal nanoparticles, silver nanoparticles are a widely used in various life sectors such as in biomedical applications, air and water purification, food production, cosmetics, garments and in various household products. There are several methods for production of silver nanoparticles. Generally, silver nanoparticles can be prepared by chemical methods such as chemical reduction and electrochemical techniques, physical methods, and biological methods such as the use of microorganisms. Th...

  3. Silver(I) complexes of 2,4-dihydroxybenzaldehyde-amino acid Schiff bases-Novel noncompetitive α-glucosidase inhibitors.

    Science.gov (United States)

    Zheng, Jingwei; Ma, Lin

    2015-01-01

    A series of silver(I) complexes of 2,4-dihydroxybenzaldehyde-amino acid Schiff bases were designed and tested for α-glucosidase inhibition. Our results indicate that all the silver complexes (4a-18a) possessed strong inhibitory activity at μmolL(-1) level, especially glutamine (12a) and histidine (18a) Schiff base silver(I) complexes exhibited an IC50 value of less than 0.01μmolL(-1). This series of compounds exhibited noncompetitive inhibition characteristics in kinetic studies. In addition, we investigated the mechanism of inhibition and the structure-activity relationships of the amino acid Schiff base silver complexes. Our results reveal that Schiff base silver complexes may be explored for their therapeutic potential as alternatives of α-glucosidase inhibitors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Bee Pollen as a Promising Agent in the Burn Wounds Treatment

    Directory of Open Access Journals (Sweden)

    Paweł Olczyk

    2016-01-01

    Full Text Available The aim of the present study was to visualize the benefits and advantages derived from preparations based on extracts of bee pollen as compared to pharmaceuticals commonly used in the treatment of burns. The bee pollen ointment was applied for the first time in topical burn treatment. Experimental burn wounds were inflicted on two white, domestic pigs. Clinical, histopathological, and microbiological assessment of specimens from burn wounds, inflicted on polish domestic pigs, treated with silver sulfadiazine or bee pollen ointment, was done. The comparative material was constituted by either tissues obtained from wounds treated with physiological saline or tissues obtained from wounds which were untreated. Clinical and histopathological evaluation showed that applied apitherapeutic agent reduces the healing time of burn wounds and positively affects the general condition of the animals. Moreover the used natural preparation proved to be highly effective antimicrobial agent, which was reflected in a reduction of the number of microorganisms in quantitative research and bactericidal activity of isolated strains. On the basis of the obtained bacteriological analysis, it may be concluded that the applied bee pollen ointment may affect the wound healing process of burn wounds, preventing infection of the newly formed tissue.

  5. Bioresorbable nanofiber-based systems for wound healing and drug delivery: optimization of fabrication parameters.

    Science.gov (United States)

    Katti, Dhirendra S; Robinson, Kyle W; Ko, Frank K; Laurencin, Cato T

    2004-08-15

    Wound healing is a complex process that often requires treatment with antibiotics. This article reports the initial development of a biodegradable polymeric nanofiber-based antibiotic delivery system. The functions of such a system would be (a) to serve as a biodegradable gauze, and (b) to serve as an antibiotic delivery system. The polymer used in this study was poly(lactide-co-glycolide) (PLAGA), and nanofibers of PLAGA were fabricated with the use of the electrospinning process. The objective of this study was to determine the effect of fabrication parameters: orifice diameter (needle gauge), polymer solution concentration, and voltage per unit length, on the morphology and diameter of electrospun nanofibers. The needle gauges studied were 16 (1.19 mm), 18 (0.84 mm), and 20 (0.58 mm), and the range of polymer solution concentration studied was from 0.10 g/mL to 0.30 g/mL. The effect of voltage was determined by varying the voltage per unit electrospinning distance, and the range studied was from 0.375 kV/cm to 1.5 kV/cm. In addition, the mass per unit area of the electrospun nanofibers as a function of time was determined and the feasibility of antibiotic (cefazolin) loading into the nanofibers was also studied. The results indicate that the diameter of nanofibers decreased with an increase in needle gauge (decrease in orifice diameter), and increased with an increase in the concentration of the polymer solution. The voltage study demonstrated that the average diameter of the nanofibers decreased with an increase in voltage. However, the effect of voltage on fiber diameter was less pronounced as compared to polymer solution concentration. The results of the areal density study indicated that the mass per unit area of the electrospun nanofibers increased linearly with time. Feasibility of drug incorporation into the nanofibers was demonstrated with the use of cefazolin, a broad-spectrum antibiotic. Overall, these studies demonstrated that PLAGA nanofibers can be

  6. Production and characterization of cornstarch/cellulose acetate/silver sulfadiazine extrudate matrices

    Energy Technology Data Exchange (ETDEWEB)

    Zepon, Karine Modolon [CIMJECT, Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); TECFARMA, Universidade do Sul de Santa Catarina, 88704-900 Tubarão, SC (Brazil); Petronilho, Fabricia [FICEXP, Universidade do Sul de Santa Catarina, 88704-900 Tubarão, SC (Brazil); Soldi, Valdir [POLIMAT, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Salmoria, Gean Vitor [CIMJECT, Departamento de Engenharia Mecânica, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Kanis, Luiz Alberto, E-mail: luiz.kanis@unisul.br [TECFARMA, Universidade do Sul de Santa Catarina, 88704-900 Tubarão, SC (Brazil)

    2014-11-01

    The production and evaluation of cornstarch/cellulose acetate/silver sulfadiazine extrudate matrices are reported herein. The matrices were melt extruded under nine different conditions, altering the temperature and the screw speed values. The surface morphology of the matrices was examined by scanning electron microscopy. The micrographs revealed the presence of non-melted silver sulfadiazine microparticles in the matrices extruded at lower temperature and screw speed values. The thermal properties were evaluated and the results for both the biopolymer and the drug indicated no thermal degradation during the melt extrusion process. The differential scanning analysis of the extrudate matrices showed a shift to lower temperatures for the silver sulfadiazine melting point compared with the non-extruded drug. The starch/cellulose acetate matrices containing silver sulfadiazine demonstrated significant inhibition of the growth of Pseudomonas aeruginosa and Staphylococcus aureus. In vivo inflammatory response tests showed that the extrudate matrices, with or without silver sulfadiazine, did not trigger chronic inflammatory processes. - Highlights: • Melt extruded bio-based matrices containing silver sulfadiazine was produced. • The silver sulfadiazine is stable during melt-extrusion. • The extrudate matrices shown bacterial growth inhibition. • The matrices obtained have potential to development wound healing membranes.

  7. Robustness analysis of a green chemistry-based model for the classification of silver nanoparticles synthesis processes

    Science.gov (United States)

    This paper proposes a robustness analysis based on Multiple Criteria Decision Aiding (MCDA). The ensuing model was used to assess the implementation of green chemistry principles in the synthesis of silver nanoparticles. Its recommendations were also compared to an earlier develo...

  8. Ultra thin hydro-films based on lactose-crosslinked fish gelatin for wound healing applications.

    Science.gov (United States)

    Etxabide, Alaitz; Vairo, Claudia; Santos-Vizcaino, Edorta; Guerrero, Pedro; Pedraz, Jose Luis; Igartua, Manoli; de la Caba, Koro; Hernandez, Rosa Maria

    2017-09-15

    This study focuses on the development and characterization of an ultra thin hydro-film based on lactose-mediated crosslinking of fish gelatin by Maillard reaction. Lactose results in the only efficient crosslinker able to produce resistant to handling hydro-films when compared to conventional crosslinkers such as glutaraldehyde or genipin (tested at 25 and 37°C in phosphate buffer saline solution (PBS)).The disappearance of the peak related to the N-containing groups (XPS) and the images obtained by SEM and AFM demonstrate the highly ordered nano-scaled structure of lactose-crosslinked gelatin, confirming the crosslinking efficiency. This dressing presents high hydrophilicity and mild occlusivity, as shown by the swelling curve (max swelling at 5min) and by the occlusion factor of 25.17±0.99%, respectively. It demonstrates high stability to hydrolysis or cell-mediated degradation. Moreover, ISO 10993-5:2009 biocompatibility assay results in undetectable cytotoxicity effects. Spreading, adhesion and proliferation assays confirm the excellent adaptability of the cells onto the hydro-film surface without invading the dressing. Finally, the hydro-film enables the controlled delivery of therapeutic factors, such as the epidermal growth factor (EGF). This study demonstrates that lactose-mediated crosslinking is able to produce ultra thin gelatin hydro-films with suitable properties for biomedical applications, such as wound healing. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Human wound photogrammetry with low-cost hardware based on automatic calibration of geometry and color

    Science.gov (United States)

    Jose, Abin; Haak, Daniel; Jonas, Stephan; Brandenburg, Vincent; Deserno, Thomas M.

    2015-03-01

    Photographic documentation and image-based wound assessment is frequently performed in medical diagnostics, patient care, and clinical research. To support quantitative assessment, photographic imaging is based on expensive and high-quality hardware and still needs appropriate registration and calibration. Using inexpensive consumer hardware such as smartphone-integrated cameras, calibration of geometry, color, and contrast is challenging. Some methods involve color calibration using a reference pattern such as a standard color card, which is located manually in the photographs. In this paper, we adopt the lattice detection algorithm by Park et al. from real world to medicine. At first, the algorithm extracts and clusters feature points according to their local intensity patterns. Groups of similar points are fed into a selection process, which tests for suitability as a lattice grid. The group which describes the largest probability of the meshes of a lattice is selected and from it a template for an initial lattice cell is extracted. Then, a Markov random field is modeled. Using the mean-shift belief propagation, the detection of the 2D lattice is solved iteratively as a spatial tracking problem. Least-squares geometric calibration of projective distortions and non-linear color calibration in RGB space is supported by 35 corner points of 24 color patches, respectively. The method is tested on 37 photographs taken from the German Calciphylaxis registry, where non-standardized photographic documentation is collected nationwide from all contributing trial sites. In all images, the reference card location is correctly identified. At least, 28 out of 35 lattice points were detected, outperforming the SIFT-based approach previously applied. Based on these coordinates, robust geometry and color registration is performed making the photographs comparable for quantitative analysis.

  10. Preparation and characterization of hybrid materials based on polypyrrole and silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen Duc Nghia; Ngo Trinh Tung [Institute of Chemistry, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Cau Giay District, Hanoi (Viet Nam)], E-mail: ducnghia264@fpt.vn

    2009-09-01

    Hybrid material is one of the most promising materials classed in the 21st century because of its unique properties and its advanced applications. In this work, hybrid materials based on polypyrrole (Ppy) and silver nanoparicles were prepared and characterized. The preparation of the hybrid material was performed by the chemical polymerization method. The structure, electrical and thermal properties of Ppy/Ag hybrid materials were characterized by XRD, SEM, and TGA and the conventional four probe method. The results showed that the Ag particles of 4-8 nm were agglomerated during the in-situ polymerization of PPy and formed some clusters with the diameter of 25 -150 nm. By the addition of Ag particles, the electrical conductivity of Ppy increased with increasing Ag concentration. The thermal stability of Ppy was significantly improved by modification with Ag particles.

  11. Preparation and characterization of hybrid materials based on polypyrrole and silver nanoparticles

    International Nuclear Information System (INIS)

    Nguyen Duc Nghia; Ngo Trinh Tung

    2009-01-01

    Hybrid material is one of the most promising materials classed in the 21st century because of its unique properties and its advanced applications. In this work, hybrid materials based on polypyrrole (Ppy) and silver nanoparicles were prepared and characterized. The preparation of the hybrid material was performed by the chemical polymerization method. The structure, electrical and thermal properties of Ppy/Ag hybrid materials were characterized by XRD, SEM, and TGA and the conventional four probe method. The results showed that the Ag particles of 4-8 nm were agglomerated during the in-situ polymerization of PPy and formed some clusters with the diameter of 25 -150 nm. By the addition of Ag particles, the electrical conductivity of Ppy increased with increasing Ag concentration. The thermal stability of Ppy was significantly improved by modification with Ag particles.

  12. Improved Flexible Transparent Conductive Electrodes based on Silver Nanowire Networks by a Simple Sunlight Illumination Approach

    Science.gov (United States)

    Kou, Pengfei; Yang, Liu; Chang, Cheng; He, Sailing

    2017-01-01

    Silver nanowire (Ag NW) networks have attracted wide attention as transparent electrodes for emerging flexible optoelectronics. However, the sheet resistance is greatly limited by large wire-to-wire contact resistances. Here, we propose a simple sunlight illumination approach to remarkably improve their electrical conductivity without any significant degradation of the light transmittance. Because the power density is extremely low (0.1 W/cm2, 1-Sun), only slight welding between Ag NWs has been observed. Despite this, a sheet resistance of solar concentrations. Due to the reduced resistance, high-performance transparent film heaters as well as efficient defrosters have been demonstrated, which are superior to the previously-reported Ag NW based film heaters. Since the sunlight is environmentally friendly and easily available, sophisticated or expensive facilities are not necessary. Our findings are particularly meaningful and show enormous potential for outdoor applications. PMID:28169343

  13. A water-based topical Chinese traditional medicine (Zicao) for wound healing developed using 2-hydroxypropyl-β-cyclodextrin.

    Science.gov (United States)

    Chen Chen, Ta; Yu, Song-Cu; Hsu, Chin-Mu; Tsai, Fuu-Jen; Tsai, Yuhsin

    2018-05-01

    Zicao is a traditional Chinese herbal medicine that has been used for the topical treatment of wounds in the form of oil-based ointment for several hundred years. To overcome the disadvantages of oil-based ointment such as irritation, discomfort, and difficulty in cleaning, this study developed a water-based topical formulation of Zicao. An ethanol extract of Zicao was included in 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) to form a water-soluble Zicao-HP-β-CD complex. The formation of the Zicao-HP-β-CD complex was determined using LC-MS, 1 H NMR, ROSEY, and solubility analysis. The bioactivity of Zicao-HP-β-CD complex in aqueous solution was evaluated using cellular uptake in vitro and experimental excision wounds in vivo. The LC-MS, 1 H NMR, ROESY, and solubility analyses results show that Zicao extract was successfully included by the HP-β-CD. The results of the cellular uptake in vitro and wound healing in vivo suggest that the effect of Zicao was enhanced following the formation of the Zicao-HP-β-CD complex. Therefore, we concluded that complexation with HP-β-CD might provide a potential method for developing an effective water-based topical solution of Zicao. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. An Advanced Multifunctional Hydrogel-Based Dressing for Wound Monitoring and Drug Delivery.

    Science.gov (United States)

    Mirani, Bahram; Pagan, Erik; Currie, Barbara; Siddiqui, Mohammad Ali; Hosseinzadeh, Reihaneh; Mostafalu, Pooria; Zhang, Yu Shrike; Ghahary, Aziz; Akbari, Mohsen

    2017-10-01

    Wound management is a major global challenge and poses a significant financial burden to the healthcare system due to the rapid growth of chronic diseases such as diabetes, obesity, and aging population. The ability to detect pathogenic infections and release drug at the wound site is of the utmost importance to expedient patient care. Herein, this study presents an advanced multifunctional dressing (GelDerm) capable of colorimetric measurement of pH, an indicator of bacterial infection, and release of antibiotic agents at the wound site. This study demonstrates the ability of GelDerm to detect bacterial infections using in vitro and ex vivo tests with accuracies comparable to the commercially available systems. Wireless interfaces to digital image capture hardware such as smartphones serve as a means for quantitation and enable the patient to record the wound condition at home and relay the information to the healthcare personnel for following treatment strategies. Additionally, the dressing is integrated within commercially available patches and can be placed on the wound without chemical or physical irritation. This study demonstrates the ability of GelDerm to eradicate bacteria by the sustained release of antibiotics. The proposed technology holds great promise in managing chronic and acute injuries caused by trauma, surgery, or diabetes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Gelam (Melaleuca spp.) Honey-Based Hydrogel as Burn Wound Dressing

    Science.gov (United States)

    Mohd Zohdi, Rozaini; Abu Bakar Zakaria, Zuki; Yusof, Norimah; Mohamed Mustapha, Noordin; Abdullah, Muhammad Nazrul Hakim

    2012-01-01

    A novel cross-linked honey hydrogel dressing was developed by incorporating Malaysian honey into hydrogel dressing formulation, cross-linked and sterilized using electron beam irradiation (25 kGy). In this study, the physical properties of the prepared honey hydrogel and its wound healing efficacy on deep partial thickness burn wounds in rats were assessed. Skin samples were taken at 7, 14, 21, and 28 days after burn for histopathological and molecular evaluations. Application of honey hydrogel dressings significantly enhanced (P < 0.05) wound closure and accelerated the rate of re-epithelialization as compared to control hydrogel and OpSite film dressing. A significant decrease in inflammatory response was observed in honey hydrogel treated wounds as early as 7 days after burn (P < 0.05). Semiquantitative analysis using RT-PCR revealed that treatment with honey hydrogel significantly (P < 0.05) suppressed the expression of proinflammatory cytokines (IL-1α, IL-1β, and IL-6). The present study substantiates the potential efficacy of honey hydrogel dressings in accelerating burn wound healing. PMID:21941590

  16. An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core

    Science.gov (United States)

    Silver nanoparticles have antibacterial properties but their use has been a cause for concern because they persist in the environment. Here we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green a...

  17. An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core

    NARCIS (Netherlands)

    Richter, A.P.; Brown, J.S.; Bharti, B.; Wang, A.; Gangwal, S.; Houck, K.; Cohen Hubal, E.A.; Paunov, V.N.; Stoyanov, S.D.; Velev, O.D.

    2015-01-01

    Silver nanoparticles have antibacterial properties, but their use has been a cause for concern because they persist in the environment. Here, we show that lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte layer form a biodegradable and green alternative to

  18. A web-based e-learning application for wound diagnosis and treatment.

    Science.gov (United States)

    Veredas, Francisco J; Ruiz-Bandera, Esperanza; Villa-Estrada, Francisca; Rufino-González, Juan F; Morente, Laura

    2014-10-01

    Pressure ulcers (PrU) are considered as one of the most challenging problems that Nursing professionals have to deal with in their daily practice. Nowadays, the education on PrUs is mainly based on traditional lecturing, seminars and face-to-face instruction, sometimes with the support of photographs of wounds being used as teaching material. This traditional educational methodology suffers from some important limitations, which could affect the efficacy of the learning process. This current study has been designed to introduce information and communication technologies (ICT) in the education on PrU for undergraduate students, with the main objective of evaluating the advantages an disadvantages of using ICT, by comparing the learning results obtained from using an e-learning tool with those from a traditional teaching methodology. In order to meet this major objective, a web-based learning system named ePULab has been designed and developed as an adaptive e-learning tool for the autonomous acquisition of knowledge on PrU evaluation. This innovative system has been validated by means of a randomized controlled trial that compares its learning efficacy with that from a control group receiving a traditional face-to-face instruction. Students using ePULab gave significantly better (p<0.01) learning acquisition scores (from pre-test mean 8.27 (SD 1.39) to post-test mean 15.83 (SD 2.52)) than those following traditional lecture-style classes (from pre-test mean 8.23 (SD 1.23) to post-test mean 11.6 (SD 2.52)). In this article, the ePULab software is described in detail and the results from that experimental educational validation study are also presented and analyzed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  19. Electrical properties of fast ion conducting silver based borate glasses: Application in solid battery

    International Nuclear Information System (INIS)

    Masoud, Emad M.; Khairy, M.; Mousa, M.A.

    2013-01-01

    Graphical abstract: -- Highlights: •AgI dopant created more opened borate network structure. •Dielectric constant and loss values increased with AgI concentration. •AgI dopant enhanced both ion migration and orientation. •0.6 AgI–0.27 Ag 2 O–0.13 B 2 O 3 showed the highest DC-conductivity at room temperature. •It showed also good life time as a solid electrolyte in solid battery at room temperature. -- Abstract: The electrical properties of the ternary ionic conducting glass system xAgI–(1 – x)[0.67Ag 2 O–0.33B 2 O 3 ], where x = 0.4 , 0.5, 0.6, 0.7 and 0.8, were studied for emphasizing the influence of silver iodide concentration on the transport properties in the based borate glasses. The glasses were prepared by melt quenching technique and characterized using X-ray diffraction (XRD), FT-IR spectra and differential thermal analysis (DTA). XRD confirmed a glassy nature for all investigated compositions. Electrical conductivity (σ), dielectric constant (ε′), dielectric loss (ε ″ ) and impedance spectra (Z′–Z′′) were studied for all samples at a frequency range of 0–10 6 Hz and over a temperature range of 303–413 K. Changes of conductivity and dielectric properties with composition, temperature and frequency were analyzed and discussed. A silver iodine battery using glassy electrolyte sample with the highest ionic conductivity (x = 0.6) was studied

  20. Randomized controlled trial on collagen/oxidized regenerated cellulose/silver treatment

    DEFF Research Database (Denmark)

    Gottrup, Finn; Cullen, Breda Mary; Karlsmark, Tonny

    2013-01-01

    Collagen/oxidized regenerated cellulose (ORC)/silver therapy has been designed to facilitate wound healing by normalizing the microenvironment and correcting biochemical imbalances in chronic wounds. The aim of this study was to compare collagen/ORC/silver therapy to control (standard treatment)....

  1. Self-made silver-bromide-based emulsions for users in holography: manufacturing, processing, and application

    Science.gov (United States)

    Duenkel, Lothar; Eichler, Juergen; Ackermann, Gerhard; Schneeweiss, Claudia

    2004-06-01

    Holography is the most fascinating technology for three-dimensional imaging. But despite of many decades of research, the seek for an ideal recording material has never been given up. From all ultra-fine materials, silver bromide emulsions with very small grain sizes have the highest sensitivity. In recent years however, many traditional manufacturers discontinued their production. Meanwhile, newcomers succeeded in manufacturing emulsions which are very suitable for holography, concerning extremely high resolution, brigthness and sensitivity1. But two problems may still linger: First, the deficient market situation for production and application on this field. Second, the reputation of the system of being extremely complicated for laboratory preparation. In such a crucial situation, the authors have succeeded in presenting a laboratory procedure for making do-it-yourself materials available to any expert who is well versed in holography, and who disposes of normal darkroom equipment2. The methodology is based on precipitation using the traditional double-jet method according to Thiry and predecessors3. But sensitization is carried out by a diffusion process according to the procedure as proposed by Blyth et al.4 Thus, precipitation and coating on one side and sensitization on the other one are separated strictly from one another. Efficient desaltation is an important process too, warranting the high opto-mechanical quality of the layer. The material has been sensitzed for HeNe-Laser radiation (632,8 nm) only up to now. The mean diameter of the silver bromide grains is about 15 nm, as determined by transmission electron microscopy (TEM). Phillips-Bjelkhagen Ultimate (PBU) or Fe3+ rehalogenation bleach are applied successfully5-6. In final result, a new generation of holograms with ultra-high resolution, proper contrast, excellent sharpness and light brightness has been obtained. Holography belongs to an advancing technology where the search for an ideal recording

  2. Antimicrobial coatings based on zinc oxide and orange oil for improved bioactive wound dressings and other applications.

    Science.gov (United States)

    Rădulescu, Marius; Andronescu, Ecaterina; Cirja, Andreea; Holban, Alina Maria; Mogoantă, LaurenŢiu; Bălşeanu, Tudor Adrian; Cătălin, Bogdan; Neagu, Tiberiu Paul; Lascăr, Ioan; Florea, Denisa Alexandra; Grumezescu, Alexandru Mihai; Ciubuca, Bianca; Lazăr, Veronica; Chifiriuc, Mariana Carmen; Bolocan, Alexandra

    2016-01-01

    This work presents a novel nano-modified coating for wound dressings and other medical devices with anti-infective properties, based on functionalized zinc oxide nanostructures and orange oil (ZnO@OO). The obtained nanosurfaces were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), selected area electron diffraction (SAED), differential thermal analysis-thermogravimetry (DTA-TG), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The obtained nanocomposite coatings exhibited an antimicrobial activity superior to bare ZnO nanoparticles (NPs) and to the control antibiotic against Staphylococcus aureus and Escherichia coli, as revealed by the lower minimal inhibitory concentration values. For the quantitative measurement of biofilm-embedded microbial cells, a culture-based, viable cell count method was used. The coated wound dressings proved to be more resistant to S. aureus microbial colonization and biofilm formation compared to the uncoated controls. These results, correlated with the good in vivo biodistribution open new directions for the design of nanostructured bioactive coating and surfaces, which can find applications in the medical field, for obtaining improved bioactive wound dressings and prosthetic devices, but also in food packaging and cosmetic industry.

  3. Antibacterial properties of an iron-based hemostatic agent in vitro and in a rat wound model.

    Science.gov (United States)

    Bracho, David O; Barsan, Lauren; Arekapudi, Subramanyeswara R; Thompson, John A; Hen, John; Stern, Susan A; Younger, John G

    2009-07-01

    Topical hemostatic agents are currently employed on the battlefield for control of major hemorrhage and have potential for use in civilian settings. Some of these compounds may also be antibacterial. Given the behavior of these compounds, the purpose of this study was to assess the potential antibacterial properties of an iron oxyacid-based topical hemostatic agent against three problematic species of wound-contaminating microorganisms: Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and methicillin-resistant Staphylococcus epidermidis. Bacteria were treated in vitro with the test powder for 30 minutes and then assessed for viability. Long-term (8-hour) inhibition of bacterial growth was also examined. In vivo, a rat full-thickness 1-cm(2) skin wound was studied. Wounds were contaminated, treated, and then quantitatively cultured 24 hours later. The lethal dose for 99% of the organisms (LD(99)) for the compound against each organism ranged from 0.89 (+/-0.28) to 4.77 (+/-0.66) mg/mL (p < 0.05). The compound produced sustained inhibition over 8 hours at both 1 and 5 mg/mL (p < 0.05 for each), for P. aeruginosa, S. epidermidis, and S. aureus. In vivo, activity was noted against only P. aeruginosa, with the largest magnitude reduction being on the order of 3-log colony-forming units (CFU; p < 0.01). The iron-based agent studied possesses significant in vitro and lesser in vivo antibacterial effects. Further optimization of the delivery, dosing, and evaluation of this agent in a larger animal model with more humanlike skin structures may reveal important wound effects beyond control of bleeding.

  4. Indirect spectrophotometric determination of sulfadiazine based on localized surface plasmon resonance peak of silver nanoparticles after cloud point extraction.

    Science.gov (United States)

    Kazemi, Elahe; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Fattahi, Mohammad Reza; Khodaveisi, Javad

    2017-12-05

    A novel, efficient, easy to use, environmentally friendly and cost-effective methodology is developed for the indirect spectrophotometric determination of sulfadiazine in different samples. The method is based on the micelle-mediated extraction of silver sulfadiazine and converting the silver content of the resultant surfactant-rich phase to the silver nanoparticles via generation of [Ag(NH 3 ) 2 ] + followed by its chemical reduction using ascorbic acid. The changes in the amplitude of localized surface plasmon resonance peak of silver nanoparticles as a function of sulfadiazine concentration in the sample solution was monitored using fiber optic linear array spectrophotometry at 457nm. The experimental conditions were thoroughly investigated and optimized. Under the optimized condition, the developed procedure showed dynamic linear calibration within the range of 10.0-800.0μgL -1 with a detection limit of 2.8μgL -1 for sulfadiazine. The relative standard deviation of the method for six replicate measurements at 150.0μgL -1 of sulfadiazine was 4.7%. The developed method was successfully applied to the determination of sulfadiazine in different samples including well water, human urine, milk and pharmaceutical formulation. Copyright © 2017. Published by Elsevier B.V.

  5. Indirect spectrophotometric determination of sulfadiazine based on localized surface plasmon resonance peak of silver nanoparticles after cloud point extraction

    Science.gov (United States)

    Kazemi, Elahe; Dadfarnia, Shayessteh; Haji Shabani, Ali Mohammad; Fattahi, Mohammad Reza; Khodaveisi, Javad

    2017-12-01

    A novel, efficient, easy to use, environmentally friendly and cost-effective methodology is developed for the indirect spectrophotometric determination of sulfadiazine in different samples. The method is based on the micelle-mediated extraction of silver sulfadiazine and converting the silver content of the resultant surfactant-rich phase to the silver nanoparticles via generation of [Ag(NH3)2]+ followed by its chemical reduction using ascorbic acid. The changes in the amplitude of localized surface plasmon resonance peak of silver nanoparticles as a function of sulfadiazine concentration in the sample solution was monitored using fiber optic linear array spectrophotometry at 457 nm. The experimental conditions were thoroughly investigated and optimized. Under the optimized condition, the developed procedure showed dynamic linear calibration within the range of 10.0-800.0 μg L- 1 with a detection limit of 2.8 μg L- 1 for sulfadiazine. The relative standard deviation of the method for six replicate measurements at 150.0 μg L- 1 of sulfadiazine was 4.7%. The developed method was successfully applied to the determination of sulfadiazine in different samples including well water, human urine, milk and pharmaceutical formulation.

  6. A prospective, multi-centre, randomised, open label, parallel, comparative study to evaluate effects of AQUACEL(®) Ag and Urgotul(®) Silver dressing on healing of chronic venous leg ulcers

    DEFF Research Database (Denmark)

    Harding, Keith; Gottrup, Finn; Jawień, Arkadiusz

    2011-01-01

    This study compared wound healing efficacy of two silver dressings, AQUACEL(®) Ag and Urgotul(®) Silver, against venous ulcers at risk of infection, over 8 weeks of treatment. The primary objective was to show non inferiority of AQUACEL(®) Ag to Urgotul(®) Silver. Patients (281) were randomised......, safety events and ulcer healing were compared. After 8 weeks of treatment, the AQUACEL(®) Ag group had a relative wound size reduction (49·65% ± 52·53%) compared with the Urgotul(®) Silver group (42·81% ± 60·0%). The non inferiority of the AQUACEL(®) Ag group to the Urgotul(®) Silver group...... was established based on the difference between them (6·84% ± 56·3%, 95% confidence interval -6·56 to 20·2) and the pre-defined non inferiority margin (-15%). Composite wound healing analysis showed that the AQUACEL(®) Ag group had statistically higher percentage of subjects with better wound progression (66...

  7. [Clinical study using activity-based costing to assess cost-effectiveness of a wound management system utilizing modern dressings in comparison with traditional wound care].

    Science.gov (United States)

    Ohura, Takehiko; Sanada, Hiromi; Mino, Yoshio

    2004-01-01

    In recent years, the concept of cost-effectiveness, including medical delivery and health service fee systems, has become widespread in Japanese health care. In the field of pressure ulcer management, the recent introduction of penalty subtraction in the care fee system emphasizes the need for prevention and cost-effective care of pressure ulcer. Previous cost-effectiveness research on pressure ulcer management tended to focus only on "hardware" costs such as those for pharmaceuticals and medical supplies, while neglecting other cost aspects, particularly those involving the cost of labor. Thus, cost-effectiveness in pressure ulcer care has not yet been fully established. To provide true cost effectiveness data, a comparative prospective study was initiated in patients with stage II and III pressure ulcers. Considering the potential impact of the pressure reduction mattress on clinical outcome, in particular, the same type of pressure reduction mattresses are utilized in all the cases in the study. The cost analysis method used was Activity-Based Costing, which measures material and labor cost aspects on a daily basis. A reduction in the Pressure Sore Status Tool (PSST) score was used to measure clinical effectiveness. Patients were divided into three groups based on the treatment method and on the use of a consistent algorithm of wound care: 1. MC/A group, modern dressings with a treatment algorithm (control cohort). 2. TC/A group, traditional care (ointment and gauze) with a treatment algorithm. 3. TC/NA group, traditional care (ointment and gauze) without a treatment algorithm. The results revealed that MC/A is more cost-effective than both TC/A and TC/NA. This suggests that appropriate utilization of modern dressing materials and a pressure ulcer care algorithm would contribute to reducing health care costs, improved clinical results, and, ultimately, greater cost-effectiveness.

  8. In vitro investigations of a novel wound dressing concept based on biodegradable polyurethane

    International Nuclear Information System (INIS)

    Rottmar, Markus; Richter, Michael; Mäder, Xenia; Grieder, Kathrin; Bruinink, Arie; Nuss, Katja; Karol, Agnieszka; Rechenberg, Brigitte von; Zimmermann, Erika; Buser, Stephan; Dobmann, Andreas; Blume, Jessica

    2015-01-01

    Non-healing and partially healing wounds are an important problem not only for the patient but also for the public health care system. Current treatment solutions are far from optimal regarding the chosen material properties as well as price and source. Biodegradable polyurethane (PUR) scaffolds have shown great promise for in vivo tissue engineering approaches, but accomplishment of the goal of scaffold degradation and new tissue formation developing in parallel has not been observed so far in skin wound repair. In this study, the mechanical properties and degradation behavior as well as the biocompatibility of a low-cost synthetic, pathogen-free, biocompatible and biodegradable extracellular matrix mimicking a PUR scaffold was evaluated in vitro. The novel PUR scaffolds were found to meet all the requirements for optimal scaffolds and wound dressings. These three-dimensional scaffolds are soft, highly porous, and form-stable and can be easily cut into any shape desired. All the material formulations investigated were found to be nontoxic. One formulation was able to be defined that supported both good fibroblast cell attachment and cell proliferation to colonize the scaffold. Tunable biodegradation velocity of the materials could be observed, and the results additionally indicated that calcium plays a crucial role in PUR degradation. Our results suggest that the PUR materials evaluated in this study are promising candidates for next-generation wound treatment systems and support the concept of using foam scaffolds for improved in vivo tissue engineering and regeneration. (focus issue paper)

  9. In vitro investigations of a novel wound dressing concept based on biodegradable polyurethane.

    Science.gov (United States)

    Rottmar, Markus; Richter, Michael; Mäder, Xenia; Grieder, Kathrin; Nuss, Katja; Karol, Agnieszka; von Rechenberg, Brigitte; Zimmermann, Erika; Buser, Stephan; Dobmann, Andreas; Blume, Jessica; Bruinink, Arie

    2015-06-01

    Non-healing and partially healing wounds are an important problem not only for the patient but also for the public health care system. Current treatment solutions are far from optimal regarding the chosen material properties as well as price and source. Biodegradable polyurethane (PUR) scaffolds have shown great promise for in vivo tissue engineering approaches, but accomplishment of the goal of scaffold degradation and new tissue formation developing in parallel has not been observed so far in skin wound repair. In this study, the mechanical properties and degradation behavior as well as the biocompatibility of a low-cost synthetic, pathogen-free, biocompatible and biodegradable extracellular matrix mimicking a PUR scaffold was evaluated in vitro . The novel PUR scaffolds were found to meet all the requirements for optimal scaffolds and wound dressings. These three-dimensional scaffolds are soft, highly porous, and form-stable and can be easily cut into any shape desired. All the material formulations investigated were found to be nontoxic. One formulation was able to be defined that supported both good fibroblast cell attachment and cell proliferation to colonize the scaffold. Tunable biodegradation velocity of the materials could be observed, and the results additionally indicated that calcium plays a crucial role in PUR degradation. Our results suggest that the PUR materials evaluated in this study are promising candidates for next-generation wound treatment systems and support the concept of using foam scaffolds for improved in vivo tissue engineering and regeneration.

  10. Electrofabrication of functional materials: Chloramine-based antimicrobial film for infectious wound treatment.

    Science.gov (United States)

    Qu, Xue; Liu, Huan; Zhang, Chuchu; Lei, Yu; Lei, Miao; Xu, Miao; Jin, Dawei; Li, Peng; Yin, Meng; Payne, Gregory F; Liu, Changsheng

    2018-06-01

    Electrical signals can be imposed with exquisite spatiotemporal control and provide exciting opportunities to create structure and confer function. Here, we report the use of electrical signals to program the fabrication of a chloramine wound dressing with high antimicrobial activity. This method involves two electrofabrication steps: (i) a cathodic electrodeposition of an aminopolysaccharide chitosan triggered by a localized region of high pH; and (ii) an anodic chlorination of the deposited film in the presence of chloride. This electrofabrication process is completed within several minutes and the chlorinated chitosan can be peeled from the electrode to yield a free-standing film. The presence of active NCl species in this electrofabricated film was confirmed with chlorination occurring first on the amine groups and then on the amide groups when large anodic charges were used. Electrofabrication is quantitatively controllable as the cathodic input controls film growth during deposition and the anodic input controls film chlorination. In vitro studies demonstrate that the chlorinated chitosan film has antimicrobial activities that depend on the chlorination degree. In vivo studies with a MRSA infected wound healing model indicate that the chlorinated chitosan film inhibited bacterial growth, induced less inflammation, developed reorganized epithelial and dermis structures, and thus promoted wound healing compared to a bare wound or wound treated with unmodified chitosan. These results demonstrate the fabrication of advanced functional materials (i.e., antimicrobial wound dressings) using controllable electrical signals to both organize structure through non-covalent interactions (i.e., induce chitosan's reversible self-assembly) and to initiate function-conferring covalent modifications (i.e., generate chloramine bonds). Potentially, electrofabrication may provide a simple, low cost and sustainable alternative for materials fabrication. We believe this work is

  11. Transport Properties Of PbI2 Doped Silver Oxysalt Based Amorphous Solid Electrolytes

    Science.gov (United States)

    Shrisanjaykumar Jayswal, Manishkumar

    Solid electrolytes are a class of materials that conduct electricity by means of motion of ions like Ag+, Na+, Li +, Cu+, H+, F-, O -2 etc. in solid phase. The host materials include crystalline, polycrystalline, glasses, polymers and composites. Ion conducting glasses are one of the most sought after solid electrolytes that are useful in various electrochemical applications like solid state batteries, gas sensors, supercapacitors, electrochromic devices, to name a few. Since the discovery of fast silver ion transport in silver oxyhalide glasses at the end of the 1960s, many glasses showing large ionic conductivity up to 10-4 10-2 S/cm at room temperature have been developed, chiefly silver and copper ion conductors. The silver ion conducting glasses owe their high ionic conductivity mainly to stabilized alpha-AgI. AgI, as we know, undergoes a structural phase transition from wurtzite (beta phase) at room temperature to body centered cubic (alpha phase) structure at temperatures higher than 146 °C. The alpha-AgI possesses approximately six order of higher ionic conductivity than beta-AgI. The high ionic conductivity of alpha-AgI is attributed to its molten sublattice type of structure, which facilitates easy Ag+ ion migration, like a liquid. And hence, several attempts have been made to stabilize it at room temperature in crystalline as well as non-crystalline hosts like oxide and non-oxide glasses. Recently, in order to stabilize AgI in glasses, instead of directly doping it, indirect routes have also been explored. Where, a metal iodide salt along with silver oxide or silver phosphate is taken and an exchange reaction permitted by Hard and Soft, Acid and Base (HSAB) principle occurs between the two and AgI and metal oxide form in the glass forming melt. Work done in the present thesis has been organized in seven chapters as follows: Chapter 1: A review and background information of different solid electrolyte materials and their development is presented. Along

  12. Managing painful chronic wounds: the Wound Pain Management Model

    DEFF Research Database (Denmark)

    Price, Patricia; Fogh, Karsten; Glynn, Chris

    2007-01-01

    of the pain experience: location, duration, intensity, quality, onset and impact on activities of daily living. Holistic management must be based on a safe and effective mix of psychosocial approaches together with local and systemic pain management. It is no longer acceptable to ignore or inadequately...... to the wound should be handled as one of the main priorities in chronic wound management together with addressing the cause. Management of pain in chronic wounds depends on proper assessment, reporting and documenting patient experiences of pain. Assessment should be based on six critical dimensions...... document persistent wound pain and not to develop a treatment and monitoring strategy to improve the lives of persons with chronic wounds. Unless wound pain is optimally managed, patient suffering and costs to health care systems will increase. Udgivelsesdato: 2007-Apr...

  13. Cost-Effectiveness Analysis in Comparing Alginate Silver Dressing with Silver Zinc Sulfadiazine Cream in the Treatment of Pressure Ulcers

    Directory of Open Access Journals (Sweden)

    Apirag Chuangsuwanich

    2013-09-01

    Full Text Available Background The treatment of pressure ulcers is complicated, given the various wound dressingproducts available. The cost of different treatments varies and the cost-effectiveness of eachproduct has not been thoroughly evaluated. We compare two wound dressing protocolsalginatesilver dressing (AlSD and silver zinc sulfadiazine cream (AgZnSD with regard towound healing and cost-effectivenessMethods Patients with grade III or IV sacral or trochanteric pressure ulcers were eligible forthis prospective, randomized controlled trial. The patients were randomized to receive oneof the two dressings for an eight-week period. The criteria of efficacy were based on thePressure Ulcer Scale for Healing (PUSH scoring tool. The cost of treatment was also assessed.Results Twenty patients (12 women and 8 men were randomly assigned to receive eitherAlSD (n=10 or AgZnSD cream (n=10. The demographic data and wound characteristics werecomparable in the two groups. The two groups showed no significant difference in the reductionof PUSH score, wound size, or volume of exudate. The tissue type score was significantlylower in the AlSD group (3.15±0.68-1.85±0.68 vs. 2.73±0.79-2.2±0.41; P=0.015. The costof treatment was significantly lower in the AlSD group (377.17 vs. 467.74 USD, respectively;P<0.0001.Conclusions Alginate silver dressing could be effectively used in the treatment of grade IIIand IV pressure ulcers. It can improve wound tissue characteristics and is cost-effective.

  14. A potential bioactive wound dressing based on carboxymethyl cellulose/ZnO impregnated MCM-41 nanocomposite hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Rakhshaei, Rasul [Research Laboratory of Dendrimers and Nanopolymers, Faculty of Chemistry, University of Tabriz, P.O. Box 51666, Tabriz (Iran, Islamic Republic of); Namazi, Hassan, E-mail: namazi@tabrizu.ac.ir [Research Laboratory of Dendrimers and Nanopolymers, Faculty of Chemistry, University of Tabriz, P.O. Box 51666, Tabriz (Iran, Islamic Republic of); Research Center for Pharmaceutical Nanotechnology, Tabriz University of Medical Science, Tabriz (Iran, Islamic Republic of)

    2017-04-01

    Lack of antibacterial activity, deficient water vapor and oxygen permeability, and insufficient mechanical properties are disadvantages of existing wound dressings. Hydrogels could absorb wound exudates due to their strong swelling ratio and give a cooling sensation and a wet environment. To overcome these shortcomings, flexible nanocomposite hydrogel films was prepared through combination of zinc oxide impregnated mesoporous silica (ZnO-MCM-41) as a nano drug carrier with carboxymethyl cellulose (CMC) hydrogel. Citric acid was used as cross linker to avoid the cytotoxicity of conventional cross linkers. The prepared nanocomposite hydrogel was characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Zeta potential and UV–vis spectroscopy. Results of swelling and erosion tests showed CMC/ZnO nanocomposite hydrogel disintegrated during the first hours of the test. Using MCM-41 as a substrate for ZnO nanoparticles solved this problem and the CMC/ZnO-MCM-41 showed a great improvement in tensile strength (12%), swelling (100%), erosion (53%) and gas permeability (500%) properties. Drug delivery and antibacterial properties of the nanocomposite hydrogel films studied using tetracycline (TC) as a broad spectrum antibiotic and showed a sustained TC release. This could efficiently decrease bandage exchange. Cytocompatibility of the nanocomposite hydrogel films has been analyzed in adipose tissue-derived stem cells (ADSCs) and results showed cytocompatibility of CMC/ZnO-MCM-41. Based on these results the prepared CMC nanocomposite hydrogel containing ZnO impregnated MCM-41, could serve as a kind of promising wound dressing with sustained drug delivery properties. - Highlights: • CMC nanocomposite hydrogel incorporated with TC loaded ZnO-MCM-41 nanoparticles have been prepared as active wound dressing. • Citric acid was used as cross linker to avoid conventional toxic crosslinkers. • CMC/ZnO-MCM-41

  15. Mineral commodity profiles: Silver

    Science.gov (United States)

    Butterman, W.C.; Hilliard, Henry E.

    2005-01-01

    Overview -- Silver is one of the eight precious, or noble, metals; the others are gold and the six platinum-group metals (PGM). World mine production in 2001 was 18,700 metric tons (t) and came from mines in 60 countries; the 10 leading producing countries accounted for 86 percent of the total. The largest producer was Mexico, followed by Peru, Australia, and the United States. About 25 percent of the silver mined in the world in 2001 came from silver ores; 15 percent, from gold ores and the remaining 60 percent, from copper, lead, and zinc ores. In the United States, 14 percent of the silver mined in 2001 came from silver ores; 39 percent, from gold ores; 10 percent, from copper and copper-molybdenum ores; and 37 percent, from lead, zinc, and lead-zinc ores. The precious metal ores (gold and silver) came from 30 lode mines and 10 placer mines; the base-metal ores (copper, lead, molybdenum, and zinc) came from 24 lode mines. Placer mines yielded less than 1 percent of the national silver production. Silver was mined in 12 States, of which Nevada was by far the largest producer; it accounted for nearly one-third of the national total. The production of silver at domestic mines generated employment for about 1,100 mine and mill workers. The value of mined domestic silver was estimated to be $290 million. Of the nearly 27,000 t of world silver that was fabricated in 2001, about one-third went into jewelry and silverware, one-fourth into the light-sensitive compounds used in photography, and nearly all the remainder went for industrial uses, of which there were 7 substantial uses and many other small-volume uses. By comparison, 85 percent of the silver used in the United States went to photography and industrial uses, 8 percent to jewelry and silverware, and 7 percent to coins and medals. The United States was the largest consumer of silver followed by India, Japan, and Italy; the 13 largest consuming countries accounted for nearly 90 percent of the world total. In the

  16. Flow electrochemical biosensors based on enzymatic porous reactor and tubular detector of silver solid amalgam

    Energy Technology Data Exchange (ETDEWEB)

    Josypčuk, Bohdan, E-mail: josypcuk@jh-inst.cas.cz [J. Heyrovský Institute of Physical Chemistry of AS CR, v.v.i., Department of Biophysical Chemistry, Dolejskova 3, Prague (Czech Republic); Barek, Jiří [Charles University in Prague, Faculty of Science, University Center of Excellence UNCE “Supramolecular Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ-128 43 Prague 2 (Czech Republic); Josypčuk, Oksana [J. Heyrovský Institute of Physical Chemistry of AS CR, v.v.i., Department of Biophysical Chemistry, Dolejskova 3, Prague (Czech Republic); Charles University in Prague, Faculty of Science, University Center of Excellence UNCE “Supramolecular Chemistry”, Department of Analytical Chemistry, UNESCO Laboratory of Environmental Electrochemistry, Albertov 6, CZ-128 43 Prague 2 (Czech Republic)

    2013-05-17

    Graphical abstract: -- Highlights: •Flow amperometric enzymatic biosensor was constructed. •The biosensor is based on a reactor of a novel material – porous silver solid amalgam. •Tubular amalgam detector was used for determination of decrease of O{sub 2} concentration. •Covalent bonds amalgam−thiol−enzyme contributed to the sensor long-term stability. •LOD of glucose was 0.01 mmol L{sup −1} with RSD = 1.3% (n = 11). -- Abstract: A flow amperometric enzymatic biosensor for the determination of glucose was constructed. The biosensor consists of a flow reactor based on porous silver solid amalgam (AgSA) and a flow tubular detector based on compact AgSA. The preparation of the sensor and the determination of glucose occurred in three steps. First, a self-assembled monolayer of 11-mercaptoundecanoic acid (MUA) was formed at the porous surface of the reactor. Second, enzyme glucose oxidase (GOx) was covalently immobilized at MUA-layer using N-ethyl-N′-(3-dimethylaminopropyl) carboimide and N-hydroxysuccinimide chemistry. Finally, a decrease of oxygen concentration (directly proportional to the concentration of glucose) during enzymatic reaction was amperometrically measured on the tubular detector under flow injection conditions. The following parameters of glucose determination were optimized with respect to amperometric response: composition of the mobile phase, its concentration, the potential of detection and the flow rate. The calibration curve of glucose was linear in the concentration range of 0.02–0.80 mmol L{sup −1} with detection limit of 0.01 mmol L{sup −1}. The content of glucose in the sample of honey was determined as 35.5 ± 1.0 mass % (number of the repeated measurements n = 7; standard deviation SD = 1.2%; relative standard deviation RSD = 3.2%) which corresponds well with the declared values. The tested biosensor proved good long-term stability (77% of the current response of glucose was retained after 35 days)

  17. Wound care centers

    Science.gov (United States)

    Pressure ulcer - wound care center; Decubitus ulcer - wound care center; Diabetic ulcer - wound care center; Surgical wound - wound ... Common types of non-healing wounds include: Pressure sores Surgical ... flow, or swollen legs Certain wounds may not heal well due to: ...

  18. Colloidosome-based synthesis of a multifunctional nanostructure of silver and hollow iron oxide nanoparticles

    KAUST Repository

    Pan, Yue

    2010-03-16

    Nanoparticles that self-assemble on a liquid-liquid interface serve as the building block for making heterodimeric nanostructures. Specifically, hollow iron oxide nanoparticles within hexane form colloidosomes in the aqueous solution of silver nitrate, and iron oxide exposed to the aqueous phase catalyzes the reduction of silver ions to afford a heterodimer of silver and hollow iron oxide nanoparticles. Transmission electron microscopy, selected area electron diffraction, energy-dispersive X-ray spectrometry, X-ray diffraction, UV-vis spectroscopy, and SQUID were used to characterize the heterodimers. Interestingly, the formation of silver nanoparticles helps the removal of spinglass layer on the hollow iron oxide nanoparticles. This work demonstrates a powerful yet convenient strategy for producing sophisticated, multifunctional nanostructures. © 2010 American Chemical Society.

  19. l-Cysteine-modified silver-functionalized silica-based material as an efficient solid-phase extraction adsorbent for the determination of bisphenol A.

    Science.gov (United States)

    Li, Yuanyuan; Zhu, Nan; Li, Bingxiang; Chen, Tong; Ma, Yulong; Li, Qiang

    2018-02-01

    A new silver-functionalized silica-based material with a core-shell structure based on silver nanoparticle-coated silica spheres was synthesized, and silver nanoparticles were modified using strongly bound l-cysteine. l-Cysteine-silver@silica was characterized by scanning electron microscopy and FTIR spectroscopy. Then, a solid-phase extraction method based on l-cysteine-silver@silica was developed and successfully used for bisphenol A determination prior to HPLC analysis. The results showed that the l-cysteine-silver@silica as an adsorbent exhibited good enrichment capability for bisphenol A, and the maximum adsorption saturation was 20.93 mg/g. Moreover, a short adsorption equilibrium time was obtained due to the presence of silver nanoparticles on the surface of the silica. The extraction efficiencies were then optimized by varying the eluents and pH. Under the optimized conditions, good linearity for bisphenol A was obtained in the range from 0.4 to 4.0 μM (R 2  > 0.99) with a low limit of detection (1.15 ng/mL). The spiked recoveries from tap water and milk samples were satisfactory (85-102%) with relative standard deviations below 5.2% (n = 3), which indicated that the method was suitable for the analysis of bisphenol A in complex samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Silver-graphene oxide based plasmonic spacer for surface plasmon-coupled fluorescence emission enhancements

    Science.gov (United States)

    Badiya, Pradeep Kumar; Srinivasan, Venkatesh; Sathish Ramamurthy, Sai

    2017-06-01

    We report the application of single layered graphene oxide (SLGO) and silver decorated SLGO (Ag-SLGO) as plasmonic spacer material for obtaining enhanced fluorescence from a Rhodamine 6G (Rh6G) radiating dipole in a surface plasmon-coupled emission platform. To this end, we have decorated SLGO with biphasic silver nanoparticles using an in situ deposition technique to achieve 112-fold fluorescence enhancements.

  1. Combat Wound Initiative program.

    Science.gov (United States)

    Stojadinovic, Alexander; Elster, Eric; Potter, Benjamin K; Davis, Thomas A; Tadaki, Doug K; Brown, Trevor S; Ahlers, Stephen; Attinger, Christopher E; Andersen, Romney C; Burris, David; Centeno, Jose; Champion, Hunter; Crumbley, David R; Denobile, John; Duga, Michael; Dunne, James R; Eberhardt, John; Ennis, William J; Forsberg, Jonathan A; Hawksworth, Jason; Helling, Thomas S; Lazarus, Gerald S; Milner, Stephen M; Mullick, Florabel G; Owner, Christopher R; Pasquina, Paul F; Patel, Chirag R; Peoples, George E; Nissan, Aviram; Ring, Michael; Sandberg, Glenn D; Schaden, Wolfgang; Schultz, Gregory S; Scofield, Tom; Shawen, Scott B; Sheppard, Forest R; Stannard, James P; Weina, Peter J; Zenilman, Jonathan M

    2010-07-01

    The Combat Wound Initiative (CWI) program is a collaborative, multidisciplinary, and interservice public-private partnership that provides personalized, state-of-the-art, and complex wound care via targeted clinical and translational research. The CWI uses a bench-to-bedside approach to translational research, including the rapid development of a human extracorporeal shock wave therapy (ESWT) study in complex wounds after establishing the potential efficacy, biologic mechanisms, and safety of this treatment modality in a murine model. Additional clinical trials include the prospective use of clinical data, serum and wound biomarkers, and wound gene expression profiles to predict wound healing/failure and additional clinical patient outcomes following combat-related trauma. These clinical research data are analyzed using machine-based learning algorithms to develop predictive treatment models to guide clinical decision-making. Future CWI directions include additional clinical trials and study centers and the refinement and deployment of our genetically driven, personalized medicine initiative to provide patient-specific care across multiple medical disciplines, with an emphasis on combat casualty care.

  2. The effect of functionalized silver nanoparticles over the thermal conductivity of base fluids

    Science.gov (United States)

    Seyhan, Merve; Altan, Cem Levent; Gurten, Berna; Bucak, Seyda

    2017-04-01

    Thermal conductivities of nanofluids are expected to be higher than common heat transfer fluids. The use of metal nanoparticles has not been intensely investigated for heat transfer applications due to lack of stability. Here we present an experimental study on the effect of silver nanoparticles (Ag NPs) which are stabilized with surfactants, on the thermal conductivity of water, ethylene glycol and hexane. Hydrophilic Ag NPs were synthesized in aqueous medium with using gum arabic as surfactant and oleic acid/oleylamine were used to stabilize Ag NPs in the organic phase. The enhancement up to 10 per cent in effective thermal conductivity of hexane and ethylene glycol was achieved with addition of Ag NPs at considerably low concentrations (i.e. 2 and 1 per cent, by weight, for hexane and ethylene glycol respectively). However, almost 10 per cent of deterioration was recorded at effective thermal conductivity of water when Ag NPs were added at 1 per cent (by wt). Considerable amount of Gum Arabic in the medium is shown to be the major contributor to this fall, causing lowering of thermal conductivity of water. Same particles performed much better in ethylene glycol where the stabilizer does not lower the thermal conductivity of the base fluid. Also thermal conductivity of nanofluids was found to be temperature independent except water based Ag nanofluids above a threshold concentration. This temperature dependency is suggested to be due to inhibition of hydrogen bonding among water molecules in the presence of high amounts of gum arabic.

  3. All printed antenna based on silver nanoparticles for 1.8 GHz applications

    Science.gov (United States)

    Hassan, Arshad; Ali, Shawkat; Bae, Jinho; Lee, Chong Hyun

    2016-08-01

    In this paper, we propose a novel printed antenna for 1.8 GHz band applications. The proposed antenna is made of silver nanoparticle-based radiating element and 0.04-mm thin, transparent and flexible polyethylene terephthalate (PET) substrate. The proposed antenna is designed and simulated by finite-element-method-based high-frequency structure simulator (HFSS). We obtain reflection coefficient of -23 dB, gain of 2.72 dBi and efficiency of 93.33 %. The resonance frequency of the antenna is also verified through national instrument (NI) Multisim simulation on the proposed equivalent circuit. We realize the antenna in a single process by commercial Dimatix material inkjet printer (DMP-3000) at ambient condition and characterize it by using vector network analyzer and spectrum analyzer. The measured reflection coefficient and -10 dB bandwidth are -32.2 dB and 190.5 MHz, respectively, which shows good agreement with HFSS and NI Multisim results. The proposed compact and optimum antenna printed on thin, transparent and fully bendable PET substrate becomes very attractive since it can overcome the limits of cost and size. These results suggest that the proposed antenna is well suitable for electronic devices operating over 1.8 GHz band such as Telos-B and other wearable printed devices.

  4. Silver nanoparticles-based colorimetric array for the detection of Thiophanate-methyl

    Science.gov (United States)

    Zheng, Mingda; Wang, Yingying; Wang, Chenge; Wei, Wei; Ma, Shuang; Sun, Xiaohan; He, Jiang

    2018-06-01

    A simple and selective colorimetric sensor based on citrate capped silver nanoparticles (Cit-AgNPs) is proposed for the detection of Thiophanate-methyl (TM) with high sensitivity and selectivity. The method based on the color change of Cit-AgNPs from yellow to cherry red with the addition of TM to Cit-AgNPs that caused a red-shift on the surface plasmon resonance (SPR) band from 394 nm to 525 nm due to the hydrogen-bonding and substitution. The density functional theory (DFT) method was also calculated the interactions between the TM and citrate ions. Under the optimized conditions, a linear relationship between the absorption ratio (A525nm/A394nm) and TM concentration was found in the range of 2-100 μM with correlation coefficient (R2) of 0.988. The detection limit of TM was 0.12 μM by UV-vis spectrometer. Moreover, the applicability of colorimetric sensor is successfully verified by the detection of TM in environmental samples with good recoveries.

  5. Silver(I)-Mediated Base Pairs in DNA Sequences Containing 7-Deazaguanine/Cytosine: towards DNA with Entirely Metallated Watson-Crick Base Pairs.

    Science.gov (United States)

    Méndez-Arriaga, José M; Maldonado, Carmen R; Dobado, José A; Galindo, Miguel A

    2018-03-26

    DNA sequences comprising noncanonical 7-deazaguanine ( 7C G) and canonical cytosine (C) are capable of forming Watson-Crick base pairs via hydrogen bonds as well as silver(I)-mediated base pairs by coordination to central silver(I) ions. Duplexes I and II containing 7C G and C have been synthesized and characterized. The incorporation of silver(I) ions into these duplexes has been studied by means of temperature-dependent UV spectroscopy, circular dichroism, and DFT calculations. The results suggest the formation of DNA molecules comprising contiguous metallated 7C G-Ag I -C Watson-Crick base pairs that preserve the original B-type conformation. Furthermore, additional studies performed on duplex III indicated that, in the presence of Ag I ions, 7C G-C and 7C A-T Watson-Crick base pairs ( 7C A, 7-deazadenine; T, thymine) can be converted to metallated 7C G-Ag I -C and 7C A-Ag I -T base pairs inside the same DNA molecule whilst maintaining its initial double helix conformation. These findings are very important for the development of customized silver-DNA nanostructures based on a Watson-Crick complementarity pattern. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Evaluation on the Presence of Nano Silver Particle in Improving a Conventional Water-based Drilling Fluid

    Science.gov (United States)

    Husin, H.; Ahmad, N.; Jamil, N.; Chyuan, O. H.; Roslan, A.

    2018-05-01

    Worldwide demand in oil and gas energy consumption has been driving many of oil and gas companies to explore new oil and gas resource field in an ultra-deep water environment. As deeper well is drilled, more problems and challenges are expected. The successful of drilling operation is highly dependent on properties of drilling fluids. As a way to operate drilling in challenging and extreme surroundings, nanotechnology with their unique properties is employed. Due to unique physicochemical, electrical, thermal, hydrodynamic properties and exceptional interaction potential of nanomaterials, nanoparticles are considered to be the most promising material of choice for smart fluid design for oil and gas field application. Throughout this paper, the effect of nano silver particle in improving a conventional water based drilling fluid was evaluated. Results showed that nano silver gave a significant improvement to the conventional water based drilling fluid in terms of its rheological properties and filtration test performance.

  7. Alloying behavior of iron, gold and silver in AlCoCrCuNi-based equimolar high-entropy alloys

    International Nuclear Information System (INIS)

    Hsu, U.S.; Hung, U.D.; Yeh, J.W.; Chen, S.K.; Huang, Y.S.; Yang, C.C.

    2007-01-01

    High-entropy alloys are newly developed alloys that are composed, by definition, of at least five principal elements with concentrations in the range of 5-35 at.%. Therefore, the alloying behavior of any given principal element is significantly affected by all the other principal elements present. In order to elucidate this further, the influence of iron, silver and gold addition on the microstructure and hardness of AlCoCrCuNi-based equimolar alloys has been examined. The as-cast AlCoCrCuNi base alloy is found to have a dendritic structure, of which only solid solution FCC and BCC phases can be observed. The BCC dendrite has a chemical composition close to that of the nominal alloy, with a deficiency in copper however, which is found to segregate and form a FCC Cu-rich interdendrite. The microstructure of the iron containing alloys is similar to that of the base alloy. It is found that both of these aforementioned alloys have hardnesses of about 420 HV, which is equated to their similar microstructures. The as-cast ingot forms two layers of distinct composition with the addition of silver. These layers, which are gold and silver in color, are determined to have a hypoeutectic Ag-Cu composition and a multielement mixture of the other principal elements, respectively. This indicates the chemical incompatibility of silver with the other principal elements. The hardnesses of the gold (104 HV) and silver layers (451 HV) are the lowest and highest of the alloy systems studied. This is attributed to the hypoeutectic Ag-Cu composition of the former and the reduced copper content of the latter. Only multielement mixtures, i.e. without copper segregation, form in the gold containing alloy. Thus, it may be said that gold acts as a 'mixing agent' between copper and the other elements. Although several of the atom pairs in the gold containing alloy have positive enthalpies, thermodynamic considerations show that the high entropy contribution is sufficient to counterbalance

  8. Elemental Mass Balance of the Hydrothermal Alteration Associated with the Baturappe Epithermal Silver-Base Metal Prospect, South Sulawesi, Indonesia

    OpenAIRE

    Nur, Irzal; Idrus, Arifudin; Pramumijoyo, Subagyo; Harijoko, Agung; Watanabe, Koichiro; Imai, Akira; Jaya, Asri; Irfan, Ulva Ria; Sufriadin

    2012-01-01

    Abstract The Baturappe prospect situated in southernmost part of Sulawesi island, Indonesia, is a hydrothermal mineralization district which is characterized by occurrences of epithermal silver-base metal mineralizations. The mineralizations hosted in basaltic-andesitic volcanic rocks of the late Middle-Miocene Baturappe Volcanics. This paper discusses a recent study of relationships between alteration mineralogy and whole-rock geochemistry, which focused on elemental mass balance calculat...

  9. Understanding long-term silver release from surface modified porous titanium implants.

    Science.gov (United States)

    Shivaram, Anish; Bose, Susmita; Bandyopadhyay, Amit

    2017-08-01

    Prevention of orthopedic device related infection (ODRI) using antibiotics has met with limited amount of success and is still a big concern during post-surgery. As an alternative, use of silver as an antibiotic treatment to prevent surgical infections is being used due to the well-established antimicrobial properties of silver. However, in most cases silver is used in particulate form with wound dressings or with short-term devices such as catheters but not with load-bearing implants. We hypothesize that strongly adherent silver to load-bearing implants can offer longer term solution to infection in vivo. Keeping that in mind, the focus of this study was to understand the long term release study of silver ions for a period of minimum 6months from silver coated surface modified porous titanium implants. Implants were fabricated using a LENS™ system, a powder based additive manufacturing technique, with at least 25% volume porosity, with and without TiO 2 nanotubes in phosphate buffer saline (pH 7.4) to see if the total release of silver ions is within the toxic limit for human cells. Considering the fact that infection sites may reduce the local pH, silver release was also studied in acetate buffer (pH 5.0) for a period of 4weeks. Along with that, the osseointegrative properties as well as cytotoxicity of porous titanium implants were assessed in vivo for a period of 12weeks using a rat distal femur model. In vivo results indicate that porous titanium implants with silver coating show comparable, if not better, biocompatibility and bonding at the bone-implant interface negating any concerns related to toxicity related to silver to normal cells. The current research is based on our recently patented technology, however focused on understanding longer-term silver release to mitigate infection related problems in load-bearing implants that can even arise several months after the surgery. Prevention of orthopedic device related infection using antibiotics has met

  10. Association of Alpha Tocopherol and Ag Sulfadiazine Chitosan Oleate Nanocarriers in Bioactive Dressings Supporting Platelet Lysate Application to Skin Wounds.

    Science.gov (United States)

    Bonferoni, Maria Cristina; Sandri, Giuseppina; Rossi, Silvia; Dellera, Eleonora; Invernizzi, Alessandro; Boselli, Cinzia; Cornaglia, Antonia Icaro; Del Fante, Claudia; Perotti, Cesare; Vigani, Barbara; Riva, Federica; Caramella, Carla; Ferrari, Franca

    2018-02-09

    Chitosan oleate was previously proposed to encapsulate in nanocarriers some poorly soluble molecules aimed to wound therapy, such as the anti-infective silver sulfadiazine, and the antioxidant α tocopherol. Because nanocarriers need a suitable formulation to be administered to wounds, in the present paper, these previously developed nanocarriers were loaded into freeze dried dressings based on chitosan glutamate. These were proposed as bioactive dressings aimed to support the application to wounds of platelet lysate, a hemoderivative rich in growth factors. The dressings were characterized for hydration capacity, morphological aspect, and rheological and mechanical behavior. Although chitosan oleate nanocarriers clearly decreased the mechanical properties of dressings, these remained compatible with handling and application to wounds. Preliminary studies in vitro on fibroblast cell cultures demonstrated good compatibility of platelet lysate with nanocarriers and bioactive dressings. An in vivo study on a murine wound model showed an accelerating wound healing effect for the bioactive dressing and its suitability as support of the platelet lysate application to wounds.

  11. Association of Alpha Tocopherol and Ag Sulfadiazine Chitosan Oleate Nanocarriers in Bioactive Dressings Supporting Platelet Lysate Application to Skin Wounds

    Directory of Open Access Journals (Sweden)

    Maria Cristina Bonferoni

    2018-02-01

    Full Text Available Chitosan oleate was previously proposed to encapsulate in nanocarriers some poorly soluble molecules aimed to wound therapy, such as the anti-infective silver sulfadiazine, and the antioxidant α tocopherol. Because nanocarriers need a suitable formulation to be administered to wounds, in the present paper, these previously developed nanocarriers were loaded into freeze dried dressings based on chitosan glutamate. These were proposed as bioactive dressings aimed to support the application to wounds of platelet lysate, a hemoderivative rich in growth factors. The dressings were characterized for hydration capacity, morphological aspect, and rheological and mechanical behavior. Although chitosan oleate nanocarriers clearly decreased the mechanical properties of dressings, these remained compatible with handling and application to wounds. Preliminary studies in vitro on fibroblast cell cultures demonstrated good compatibility of platelet lysate with nanocarriers and bioactive dressings. An in vivo study on a murine wound model showed an accelerating wound healing effect for the bioactive dressing and its suitability as support of the platelet lysate application to wounds.

  12. Silver-induced reconstruction of an adeninate-based metal-organic framework for encapsulation of luminescent adenine-stabilized silver clusters.

    Science.gov (United States)

    Jonckheere, Dries; Coutino-Gonzalez, Eduardo; Baekelant, Wouter; Bueken, Bart; Reinsch, Helge; Stassen, Ivo; Fenwick, Oliver; Richard, Fanny; Samorì, Paolo; Ameloot, Rob; Hofkens, Johan; Roeffaers, Maarten B J; De Vos, Dirk E

    2016-05-21

    Bright luminescent silver-adenine species were successfully stabilized in the pores of the MOF-69A (zinc biphenyldicarboxylate) metal-organic framework, starting from the intrinsically blue luminescent bio-MOF-1 (zinc adeninate 4,4'-biphenyldicarboxylate). Bio-MOF-1 is transformed to the MOF-69A framework by selectively leaching structural adenine linkers from the original framework using silver nitrate solutions in aqueous ethanol. Simultaneously, bright blue-green luminescent silver-adenine clusters are formed inside the pores of the recrystallized MOF-69A matrix in high local concentrations. The structural transition and concurrent changes in optical properties were characterized using a range of structural, physicochemical and spectroscopic techniques (steady-state and time-resolved luminescence, quantum yield determination, fluorescence microscopy). The presented results open new avenues for exploring the use of MOFs containing luminescent silver clusters for solid-state lighting and sensor applications.

  13. Incisional Negative Pressure Wound Therapy

    DEFF Research Database (Denmark)

    Hyldig, Nana

    the rate of surgical wound infection and wound exudate post-caesarean and that wound infection had a negative impact on quality of life one month after surgery. Alongside the clinical trial, a trial-based cost-effectiveness analysis demonstrated that the treatment is cost-effective in a high......Women with a pre-gestational body mass index (BMI) above 30 kg/m2 giving birth by caesarean section are at high risk of surgical wound infection compared with women with a BMI below 30 kg/m2. Incisional Negative Pressure Wound Therapy (iNPWT) is one strategy to reduce the rate of surgical wound...... a randomised controlled trial in two tertiary and three teaching hospitals in three regions of Denmark, the Happy Belly Study, investigating the effectiveness of iNPWT in a population of obese women after caesarean section. The Happy Belly Study has demonstrated that prophylactic iNPWT significantly reduced...

  14. Silver nanowire based flexible electrodes with improved properties: High conductivity, transparency, adhesion and low haze

    International Nuclear Information System (INIS)

    Kiran Kumar, A.B.V.; Wan Bae, Chang; Piao, Longhai; Kim, Sang-Ho

    2013-01-01

    Graphical abstract: This graphical abstract illustrates the schematic representation of the main drawbacks and rectifications for AgNWs based transparent electrodes. - Highlights: • Films exhibited low sheet resistance and optical properties with R s ≤ 30 Ω/□ and T ≥ 90%. • We decreased haze to 2% by controlling AgNWs length, diameter, and concentration. • We achieved good adhesion for AgNWs on PET film. • There is no significant change in resistance in the bending angle from 0° to 180°, and on twisting. - Abstract: Recent work has been focusing on solution processable transparent electrodes for various applications including solar cells and displays. As well as, the research aims majorly at silver nanowires (AgNWs) to replace ITO. We enhance the transparent electrode performance as a function of optical and mechanical properties with low sheet resistance, by controlling the AgNWs accept ratios, ink composition, and processing conditions. The nanowire network of transparent films agrees with the 2D percolation law. The film transmittance values at 550 nm are coping with a reference ITO film. Sheet resistance and haze values are suitable for flexible electronic applications. We fabricate transparent flexible film using a low-cost processing technique

  15. Immobilization of silver nanoparticles in Zr-based MOFs: induction of apoptosis in cancer cells

    Science.gov (United States)

    Han, Congcong; Yang, Jian; Gu, Jinlou

    2018-03-01

    Silver nanoparticles (AgNPs) are a potential class of nanomaterial for antibiosis and chemotherapeutic effects against human carcinoma cells. However, the DNA-damaging ability of free AgNPs pose the critical issues in their biomedical applications. Herein, we demonstrated a facile method to capture Ag+ ions and reduce them into active AgNPs within Zr-based metal-organic frameworks (MOFs) of UiO-66 with a mild reductant of DMF (AgNPs@UiO-66(DMF)). The average diameters of UiO-66 carriers and AgNPs were facilely controlled to be 140 and 10 nm, respectively. The obtained UiO-66 nanocarriers exhibited excellent biocompatibility and could be effectively endocytosed by cancer cells. Additionally, the AgNPs@UiO-66(DMF) could rapidly release Ag+ ions and efficiently inhibit the growth of cancer cells. The half maximal inhibitory concentration (IC50) values of the encapsulated AgNPs were calculated to be 2.7 and 2.45 μg mL-1 for SMMC-7721 and HeLa cells, respectively, which were much lower than those of free AgNPs in the reported works. Therefore, the developed AgNPs@UiO-66(DMF) not only maintained the therapeutic effect against cancer cells but also reduced the dosage of free AgNPs in chemotherapy treatment. [Figure not available: see fulltext.

  16. Silver nanowire based flexible electrodes with improved properties: High conductivity, transparency, adhesion and low haze

    Energy Technology Data Exchange (ETDEWEB)

    Kiran Kumar, A.B.V.; Wan Bae, Chang; Piao, Longhai, E-mail: piaolh@kongju.ac.kr; Kim, Sang-Ho, E-mail: sangho1130@kongju.ac.kr

    2013-08-01

    Graphical abstract: This graphical abstract illustrates the schematic representation of the main drawbacks and rectifications for AgNWs based transparent electrodes. - Highlights: • Films exhibited low sheet resistance and optical properties with R{sub s} ≤ 30 Ω/□ and T ≥ 90%. • We decreased haze to 2% by controlling AgNWs length, diameter, and concentration. • We achieved good adhesion for AgNWs on PET film. • There is no significant change in resistance in the bending angle from 0° to 180°, and on twisting. - Abstract: Recent work has been focusing on solution processable transparent electrodes for various applications including solar cells and displays. As well as, the research aims majorly at silver nanowires (AgNWs) to replace ITO. We enhance the transparent electrode performance as a function of optical and mechanical properties with low sheet resistance, by controlling the AgNWs accept ratios, ink composition, and processing conditions. The nanowire network of transparent films agrees with the 2D percolation law. The film transmittance values at 550 nm are coping with a reference ITO film. Sheet resistance and haze values are suitable for flexible electronic applications. We fabricate transparent flexible film using a low-cost processing technique.

  17. Strategies for the AFM-based manipulation of silver nanowires on a flat surface

    Science.gov (United States)

    Liu, Hong-Zhi; Wu, Sen; Zhang, Jun-Ming; Bai, Hui-Tian; Jin, Fan; Pang, Hai; Hu, Xiao-Dong

    2017-09-01

    Silver nanowires (Ag NWs) are a promising material for building various sensors and devices at the nanoscale. However, the fast and precise placement of individual Ag NWs is still a challenge today. Atomic force microscopy (AFM) has been widely used to manipulate nanoparticles, yet this technology encounters many difficulties when being applied to the movement of Ag NWs as well as other soft one-dimensional (1D) materials, since the samples are easily distorted or even broken due to friction and adhesion on the substrate. In this paper, two novel manipulation strategies based on the parallel pushing method are presented. This method applies a group of short parallel pushing vectors (PPVs) to the Ag NW along its longitudinal direction. Identical and proportional vectors are respectively proposed to translate and rotate the Ag NWs with a straight-line configuration. The rotation strategy is also applied to straighten flexed Ag NWs. The finite element method simulation is introduced to analyse the behaviour of the Ag NWs as well as to optimize the parameter setting of the PPVs. Experiments are carried out to confirm the efficiency of the presented strategies. By comprehensive application of the new strategies, four Ag NWs are continuously assembled in a rectangular pattern. This study improves the controllability of the position and configuration of Ag NWs on a flat substrate. It also indicates the practicability of automatic nanofabrication using common AFMs.

  18. Optical spectra of composite silver-porous silicon (Ag-pSi) nanostructure based periodical lattice

    Science.gov (United States)

    Amedome Min-Dianey, Kossi Aniya; Zhang, Hao-Chun; Brohi, Ali Anwar; Yu, Haiyan; Xia, Xinlin

    2018-03-01

    Numerical finite differential time domain (FDTD) tools were used in this study for predicting the optical characteristics through the nanostructure of composite silver-porous silicon (Ag-pSi) based periodical lattice. This is aimed at providing an interpretation of the optical spectra at known porosity in improvement of the light manipulating efficiency through a proposed structure. With boundary conditions correctly chosen, the numerical simulation was achieved using FDTD Lumerical solutions. This was used to investigate the effect of porosity and the number of layers on the reflection, transmission and absorption characteristics through a proposed structure in a visible wavelength range of 400-750 nm. The results revealed that the higher the number of layers, the lower the reflection. Also, the reflection increases with porosity increase. The transmission characteristics were the inverse to those found in the case of reflection spectra and optimum transmission was attained at high number of layers. Also, increase in porosity results in reduced transmission. Increase in porosity as well as in the number of layers led to an increase in absorption. Therefore, absorption into such structure can be enhanced by elevating the number of layers and the degree of porosity.

  19. Colorimetric detection of ammonia using smartphones based on localized surface plasmon resonance of silver nanoparticles.

    Science.gov (United States)

    Amirjani, Amirmostafa; Fatmehsari, Davoud Haghshenas

    2018-01-01

    In this work, a rapid and straightforward method was developed for colorimetric determination of ammonia using smartphones. The mechanisms is based on the manipulation of the surface plasmon band of silver nanoparticles (AgNPs) via the formation of Ag (NH 3 ) 2 + complex. This complex decreases the amount of AgNPs in the solution and consequently, the color intensity of the colloidal system decreases. Not only the variation in color intensity of the solution can be tracked by a UV-vis spectrophotometer, but also a smartphone can be employed to monitor the color intensity variation by RGB analysis. Ammonia, in the concentration range of 10-1000mgL -1 , was successfully measured spectrophotometrically (UV-vis spectrophotometer) and colorimetrically (RGB measurement) with the detection limit of 180 and 200mgL -1 , respectively. Linear relationships were also developed for both methods. Also, the response time of the developed colorimetric sensor was around 20s. Both of the colorimetric and spectrophotometric methods showed a reliable performance for determination of ammonia in the real samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Silver/polysaccharide-based nanofibrous materials synthesized from green chemistry approach.

    Science.gov (United States)

    Martínez-Rodríguez, M A; Garza-Navarro, M A; Moreno-Cortez, I E; Lucio-Porto, R; González-González, V A

    2016-01-20

    In this contribution a novel green chemistry approach for the synthesis of nanofibrous materials based on blends of carboxymethyl-cellulose (CMC)-silver nanoparticles (AgNPs) composite and polyvinyl-alcohol (PVA) is proposed. These nanofibrous materials were obtained from the electrospinning of blends of aqueous solutions of CMC-AgNPs composite and PVA, which were prepared at different CMC/PVA weight ratios in order to electrospin nanofibers applying a constant tension of 15kV. The synthesized materials were characterized by means of transmission electron microscopy, scanning electron microscopy; as well as Fourier-transform infrared, ultraviolet and Raman spectroscopic techniques. Experimental evidence suggests that the diameter of the nanofibers is thinner than any other reported in the literature regarding the electrospinning of CMC. This feature is related to the interactions of AgNPs with carboxyl functional groups of the CMC, which diminish those between the later and acetyl groups of PVA. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Evaluation of the influence of sulfur-based functional groups on the embedding of silver nanoparticles into the pores of MCM-41

    International Nuclear Information System (INIS)

    Oliveira, Roselaine da S.; Camilo, Fernanda F.; Bizeto, Marcos A.

    2016-01-01

    The incorporation of noble metals in the pores of mesoporous silicas might produce materials with interesting catalytic and sensing capabilities, but the proper control of pore filling and the avoidance of nanoparticles migration to outside the pores are processes not yet completely understood. In this work, we evaluated the role of –SH and –SO_3H groups post-grafted into MCM-41 on the production of silver nanoparticles by using 1-butanol as reducing agent. Thiol groups were the most efficient on promoting the formation of nanoparticles within the pores. Conversely, sulfonic groups establish electrostatic interactions with silver cations that preclude the formation of nanoparticle in yields comparable to thiol groups. MCM-41 without functional groups did not have good affinity to silver and the nanoparticles are produced outside the pores. This study showed the importance on selecting an adequate surface functional group in order to obtain silver nanoparticles filling the pores of MCM-41. - Graphical abstract: Silver nanoparticles formation inside the pores of sulfur-groups functionalized mesoporous silica. - Highlights: • Silver nanoparticles formation inside the pores of mesoporous silica. • n-butanol as reducing agent of impregnated silver cations. • Tuning the silica surface properties by grafting sulfur-based functional groups. • Influence on the loading and distribution of the nanoparticles through the pores.

  2. Endothelial cell-based methods for the detection of cyanobacterial anti-inflammatory and wound-healing promoting metabolites.

    Science.gov (United States)

    Wiesner, Christoph; Kopecky, Jiri; Pflueger, Maren; Hundsberger, Harald; Entler, Barbara; Kleber, Christoph; Atzler, Josef; Hrouzek, Pavel; Stys, Dalibor; Lukesova, Alena; Schuett, Wolfgang; Lucas, Rudolf

    2007-12-01

    Acute lung injury is accompanied by an increased endothelial chemokine production and adhesion molecule expression, which may result in an extensive neutrophil infiltration. Moreover, a destruction of the alveolar epithelium and capillary endothelium may result in permeability edema. As such, the search for novel anti-inflammatory substances, able to downregulate these parameters as well as the tissue damage holds therapeutic promise. We therefore describe here the use of human endothelial cell-based in vitro assays for the detection of anti-inflammatory and wound-healing metabolites from cyanobacteria.

  3. TOPICAL ESTROGEN IN WOUND HEALING: A DOUBLE BLIND RANDOMIZED CLINICAL TRIAL ON YOUNG HEALTHY PEOPLE

    Directory of Open Access Journals (Sweden)

    A ASILIAN

    2001-03-01

    Full Text Available Introduction: Acceleration of wounf healing is intrested because of decreasing the risk of wound complication and infections as well as reducing the cost of treatment. In animal models, it has been proved that estrogen can accelerate wound healing. It has been also suggested that topical estrogen can eliminate effect of aging on wound healing and can increase the speed of wound healing in old people. Methods: We selected 16 young healthy people who developed symmetrical and ulcers (regarding size and depths after dermabrasion, shave and electrocoagulouzon and CO2 laser. Primary lesions of patients were benign and noninfective. Identical and symmetrical lesions of each patient were randomly divided into two groups (A and B. Topical estrogen with concentration of 0.625 mg/g in the base of silver sulfadiazine cream was applied to A ulcers and silver sulfadiazine cream alone was applied on B ulcers. Ulcers were dressed by Telfa gauzes. The A ulcers of each patients were compared to counterpart B ulcers in regard of redness, size, depth, general appearance of ulcers and wound healing duration at three days intervals by a physician. Results: Average time of healing was 10.8 days and 8.5 days for B (n=29 and A (n=29 ulcers, respectively (P < 0.001. In 78 percent of cases, the A ulcers were judged better than B ulcers by physician (P < 0.01. Discussion: It seems that estrogen not only accelerate healing of acute ulcers but also it is efficient in young healthy people who don"t have any hormonal or wound healing problems.

  4. Silver nanoparticles plasmon resonance-based method for the determination of uric acid in human plasma and urine samples

    International Nuclear Information System (INIS)

    Amjadi, M.; Rahimpour, E.

    2012-01-01

    We have developed a simple and sensitive colorimetric procedure for the quantification of trace amounts of uric acid. It is based on the finding that uric acid in a medium containing ammonia and sodium hydroxide at 65 0 C can reduce silver ions to form yellow silver nanoparticles (Ag NPs). These are stabilized in solution by using poly(vinyl alcohol) as a capping agent. The yellow color of the solution that results from the localized surface plasmon resonance of Ag NPs can be observed by the bare eye. The absorbance at 415 nm is proportional to the concentration of uric acid which therefore can be determined quantitatively. The calibration curve is linear in the concentration range from 10 to 200 nM, with a limit of detection of 3.3 nM. The method was successfully applied to the determination of uric acid in human plasma and urine samples. (author)

  5. An evidence-based environmental perspective of manufactured silver nanoparticle in syntheses and applications: A systematic review and critical appraisal of peer-reviewed scientific papers

    International Nuclear Information System (INIS)

    Tolaymat, Thabet M.; El Badawy, Amro M.; Genaidy, Ash; Scheckel, Kirk G.; Luxton, Todd P.; Suidan, Makram

    2010-01-01

    Background: Most recently, renewed interest has arisen in manufactured silver nanomaterials because of their unusually enhanced physicochemical properties and biological activities compared to the bulk parent materials. A wide range of applications has emerged in consumer products ranging from disinfecting medical devices and home appliances to water treatment. Because the hypothesized mechanisms that govern the fate and transport of bulk materials may not directly apply to materials at the nanoscale, there are great concerns in the regulatory and research communities about potential environmental impacts associated with the use of silver nanoparticles. In particular, the unlimited combinations of properties emerging from the syntheses and applications of silver nanoparticles are presenting an urgent need to document the predominant salt precursors, reducing agents and stabilizing agents utilized in the synthesis processes of silver nanoparticles to guide the massive efforts required for environmental risk assessment and management. Objectives: The primary objective of this study is to present an evidence-based environmental perspective of silver nanoparticle properties in syntheses and applications. The following specific aims are designed to achieve the study objective: Aim 1 - to document the salt precursors and agents utilized in synthesizing silver nanoparticles; Aim 2 - to determine the characteristics of silver nanoparticles currently in use in the scientific literature when integrated in polymer matrices to form nanocomposites and combined with other metal nanoparticles to form bimetallic nanoparticles; Aim 3 - to provide a summary of the morphology of silver nanoparticles; and (4) Aim 4 - to provide an environmental perspective of the evidence presented in Aims 1 to 3. Methods: A comprehensive electronic search of scientific databases was conducted in support of the study objectives. Specific inclusion criteria were applied to gather the most pertinent

  6. An evidence-based environmental perspective of manufactured silver nanoparticle in syntheses and applications: A systematic review and critical appraisal of peer-reviewed scientific papers

    Energy Technology Data Exchange (ETDEWEB)

    Tolaymat, Thabet M., E-mail: tolaymat.thabet@epa.gov [USEPA Office of Research and Development, National Risk Management Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45224 (United States); El Badawy, Amro M. [Dept. of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH (United States); Genaidy, Ash [WorldTek Inc, Cincinnati, OH (United States); Scheckel, Kirk G.; Luxton, Todd P. [USEPA Office of Research and Development, National Risk Management Laboratory, 26 West Martin Luther King Drive, Cincinnati, OH 45224 (United States); Suidan, Makram [Dept. of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH (United States)

    2010-02-01

    Background: Most recently, renewed interest has arisen in manufactured silver nanomaterials because of their unusually enhanced physicochemical properties and biological activities compared to the bulk parent materials. A wide range of applications has emerged in consumer products ranging from disinfecting medical devices and home appliances to water treatment. Because the hypothesized mechanisms that govern the fate and transport of bulk materials may not directly apply to materials at the nanoscale, there are great concerns in the regulatory and research communities about potential environmental impacts associated with the use of silver nanoparticles. In particular, the unlimited combinations of properties emerging from the syntheses and applications of silver nanoparticles are presenting an urgent need to document the predominant salt precursors, reducing agents and stabilizing agents utilized in the synthesis processes of silver nanoparticles to guide the massive efforts required for environmental risk assessment and management. Objectives: The primary objective of this study is to present an evidence-based environmental perspective of silver nanoparticle properties in syntheses and applications. The following specific aims are designed to achieve the study objective: Aim 1 - to document the salt precursors and agents utilized in synthesizing silver nanoparticles; Aim 2 - to determine the characteristics of silver nanoparticles currently in use in the scientific literature when integrated in polymer matrices to form nanocomposites and combined with other metal nanoparticles to form bimetallic nanoparticles; Aim 3 - to provide a summary of the morphology of silver nanoparticles; and (4) Aim 4 - to provide an environmental perspective of the evidence presented in Aims 1 to 3. Methods: A comprehensive electronic search of scientific databases was conducted in support of the study objectives. Specific inclusion criteria were applied to gather the most pertinent

  7. TTC- Based Test as an Efficient Method to Determine Antibiofilm Activity of Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Chojniak Joanna

    2017-01-01

    Full Text Available Among metal nanoparticles, silver nanoparticles are a widely used in various life sectors such as in biomedical applications, air and water purification, food production, cosmetics, garments and in various household products. There are several methods for production of silver nanoparticles. Generally, silver nanoparticles can be prepared by chemical methods such as chemical reduction and electrochemical techniques, physical methods, and biological methods such as the use of microorganisms. The biological route of synthesis provides a great diversity in choice for its raw materials such as bacteria, algae, fungi and plants. The aim of the study was to evaluate the tetrazolium/formazan test as a method to determine antibiofilm activity of biological synthetized silver nanoparticles. In this study Bacillus subtilis grown on brewery effluent and produced biosurfactant was used for silver nanoparticles (Ag-NPs synthesis. The culture supernatants were used in synthesis of Ag-NPs. The formation of nanoparticles accompanied by colour changes of the used reaction system was confirmed by UV-vis spectroscopy. The bacteria isolated from the biofilm of water supply system were used in the evaluation of the antibiofilm activity of biologically synthetized Ag-NPs. To compare the results the commonly used crystal violet assay (CV for biofilm analysis was applied.

  8. WOUND CARE DRESSING IN DEVELOPING COUNTRIES: THE ...

    African Journals Online (AJOL)

    Dr. Ismail Adigun

    commonly available to wound care provider are traditional agents such as ... the use of the commonly available products based on the needs of a different .... The cost of care of these patients' wound dressing per ... and haemostatic activity .

  9. High Photon-to-Current Conversion in Solar Cells Based on Light-Absorbing Silver Bismuth Iodide.

    Science.gov (United States)

    Zhu, Huimin; Pan, Mingao; Johansson, Malin B; Johansson, Erik M J

    2017-06-22

    Here, a lead-free silver bismuth iodide (AgI/BiI 3 ) with a crystal structure with space group R3‾ m is investigated for use in solar cells. Devices based on the silver bismuth iodide deposited from solution on top of TiO 2 and the conducting polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) as a hole-transport layer are prepared and the photovoltaic performance is very promising with a power conversion efficiency over 2 %, which is higher than the performance of previously reported bismuth-halide materials for solar cells. Photocurrent generation is observed between 350 and 700 nm, and the maximum external quantum efficiency is around 45 %. The results are compared to solar cells based on the previously reported material AgBi 2 I 7 , and we observe a clearly higher performance for the devices with the new silver and bismuth iodides composition and different crystal structure. The X-ray diffraction spectrum of the most efficient silver bismuth iodide material shows a hexagonal crystal structure with space group R3‾ m, and from the light absorption spectrum we obtain an indirect band gap energy of 1.62 eV and a direct band gap energy of 1.85 eV. This report shows the possibility for finding new structures of metal-halides efficient in solar cells and points out new directions for further exploration of lead-free metal-halide solar cells. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  10. A Humidity Sensor Based on Silver Nanoparticles Thin Film Prepared by Electrostatic Spray Deposition Process

    Directory of Open Access Journals (Sweden)

    Thutiyaporn Thiwawong

    2013-01-01

    Full Text Available In this work, thin film of silver nanoparticles for humidity sensor application was deposited by electrostatic spray deposition technique. The influence of the deposition times on properties of films was studied. The crystal structures of sample films, their surface morphology, and optical properties have been investigated by X-ray diffraction (XRD, field emission scanning electron microscopy (FE-SEM, and UV-VIS spectrophotometer, respectively. The crystalline structure of silver nanoparticles thin film was found in the orientation of (100 and (200 planes of cubic structure at diffraction angles 2θ  =  38.2° and 44.3°, respectively. Moreover, the silver nanoparticles thin films humidity sensor was fabricated onto the interdigitated electrodes. The sensor exhibited the humidity adsorption and desorption properties. The sensing mechanisms of the device were also elucidated by complex impedance analysis.

  11. Food safety concerns deriving from the use of silver based food packaging materials: a case study.

    Directory of Open Access Journals (Sweden)

    Alessandra ePezzuto

    2015-10-01

    Full Text Available The formulation of innovative packaging solutions, exerting a functional antimicrobial role in slowing down food spoilage, is expected to have a significant impact on the food industry, allowing both the maintenance of food safety criteria for longer periods and the reduction of food waste. Different materials are considered able to exert the required antimicrobial activity, among which are materials containing silver. However, challenges exist in the application of silver to food contact materials due to knowledge gaps in the production of ingredients, stability of delivery systems in food matrices and health risks caused by the same properties which also offer the benefits. Aims of the present study were to test the effectiveness and suitability of two packaging systems, one of which contained silver, for packaging and storing Stracchino cheese, a typical Italian fresh cheese, and to investigate if there was any potential for consumers to be exposed to silver, via migration from the packaging to the cheese. Results did not show any significant difference in the effectiveness of the packaging systems on packaged Stracchino cheese, excluding that the active packaging systems exerted an inhibitory effect on the growth of spoilage microorganisms. Moreover, silver migrated into the cheese matrix throughout the storage time (24 days. Silver levels in cheese finally exceeded the maximum established level for the migration of a non-authorised substance through a functional barrier (Commission Regulation (EC No. 450/2009. This result poses safety concerns and strongly suggests the need for more research aimed at better characterizing the new packaging materials in terms of their potential impacts on human health and the environment.

  12. Silver niobates

    International Nuclear Information System (INIS)

    Tanirbergenov, B.; Rozhenko, S.P.

    1979-01-01

    By means of determination of residual concentrations and pH measurements investigated are the AgNO 3 -KNbO 3 -H 2 O, AgNO 3 -K 3 NbO 4 -H 2 O, AgNO 3 -K 8 Nb 16 O 19 -H 2 O systems and established is formation of meta-, ortho-and hexaniobates of silver. AgNbO 3 x H 2 O, Ag 8 Nb 6 O 19 x 6H 2 O and Ag 3 NbO 3 x 2.5H 2 O are separated from aqueous solution. Using the methods of differential-thermal, thermogravimetric and X-ray-phase analyses it is shown that silver metaniobate transforms into the crystal state at 530 deg C. Ortho- and hexaniobate of silver decompose at 500 deg C with formation of silver metaniobate and metal silver

  13. Amalgamation based optical and colorimetric sensing of mercury(II) ions with silver graphene oxide nanocomposite materials

    International Nuclear Information System (INIS)

    Kamali, Khosro Zangeneh; Pandikumar, Alagarsamy; Jayabal, Subramaniam; Huang, Nay Ming; Ramaraj, Ramasamy; Lim, Hong Ngee; Ong, Boon Hoong; Bien, Chia Sheng Daniel; Kee, Yeh Yee

    2016-01-01

    The article describes a facile method for the preparation of a conjugate composed of silver nanoparticles and graphene oxide (Ag GO) via chemical reduction of silver precursors in the presence of graphene oxide (GO) while sonicating the solution. The Ag GO was characterized by X-ray photoelectron spectroscopy, X-ray powder diffraction, and energy-dispersive X-ray spectroscopy. The nanocomposite undergoes a color change from yellow to colorless in presence of Hg(II), and this effect is based on the disappearance of the localized surface plasmon resonance absorption of the AgNPs due to the formation of silver-mercury amalgam. The presence of GO, on the other hand, prevents the agglomeration of the AgNPs and enhances the stability of the nanocomposite material in solution. Hence, the probe represents a viable optical probe for the determination of mercury(II) ions in that it can be used to visually detect Hg(II) concentrations as low as 100 μM. The instrumental LOD is 338 nM. (author)

  14. A potential bioactive wound dressing based on carboxymethyl cellulose/ZnO impregnated MCM-41 nanocomposite hydrogel.

    Science.gov (United States)

    Rakhshaei, Rasul; Namazi, Hassan

    2017-04-01

    Lack of antibacterial activity, deficient water vapor and oxygen permeability, and insufficient mechanical properties are disadvantages of existing wound dressings. Hydrogels could absorb wound exudates due to their strong swelling ratio and give a cooling sensation and a wet environment. To overcome these shortcomings, flexible nanocomposite hydrogel films was prepared through combination of zinc oxide impregnated mesoporous silica (ZnO-MCM-41) as a nano drug carrier with carboxymethyl cellulose (CMC) hydrogel. Citric acid was used as cross linker to avoid the cytotoxicity of conventional cross linkers. The prepared nanocomposite hydrogel was characterized using X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Zeta potential and UV-vis spectroscopy. Results of swelling and erosion tests showed CMC/ZnO nanocomposite hydrogel disintegrated during the first hours of the test. Using MCM-41 as a substrate for ZnO nanoparticles solved this problem and the CMC/ZnO-MCM-41 showed a great improvement in tensile strength (12%), swelling (100%), erosion (53%) and gas permeability (500%) properties. Drug delivery and antibacterial properties of the nanocomposite hydrogel films studied using tetracycline (TC) as a broad spectrum antibiotic and showed a sustained TC release. This could efficiently decrease bandage exchange. Cytocompatibility of the nanocomposite hydrogel films has been analyzed in adipose tissue-derived stem cells (ADSCs) and results showed cytocompatibility of CMC/ZnO-MCM-41. Based on these results the prepared CMC nanocomposite hydrogel containing ZnO impregnated MCM-41, could serve as a kind of promising wound dressing with sustained drug delivery properties. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. In vitro characterization of multivalent adhesion molecule 7-based inhibition of multidrug-resistant bacteria isolated from wounded military personnel

    Science.gov (United States)

    Krachler, Anne Marie; Mende, Katrin; Murray, Clinton; Orth, Kim

    2012-01-01

    Treatment of wounded military personnel at military medical centers is often complicated by colonization and infection of wounds with pathogenic bacteria. These include nosocomially transmitted, often multidrug-resistant pathogens such as Acinetobacter baumannii-calcoaceticus complex, Pseudomonas aeruginosa and extended spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae. We analyzed the efficacy of multivalent adhesion molecule (MAM) 7-based anti-adhesion treatment of host cells against aforementioned pathogens in a tissue culture infection model. Herein, we observed that a correlation between two important hallmarks of virulence, attachment and cytotoxicity, could serve as a useful predictor for the success of MAM7-based inhibition against bacterial infections. Initially, we characterized 20 patient isolates (five from each pathogen mentioned above) in terms of genotypic diversity, antimicrobial susceptibility and important hallmarks of pathogenicity (biofilm formation, attachment to and cytotoxicity toward cultured host cells). All isolates displayed a high degree of genotypic diversity, which was also reflected by large strain-to-strain variability in terms of biofilm formation, attachment and cytotoxicity within each group of pathogen. Using non-pathogenic bacteria expressing MAM7 or latex beads coated with recombinant MAM7 for anti-adhesion treatment, we showed a decrease in cytotoxicity, indicating that MAM7 has potential as a prophylactic agent to attenuate infection by multidrug-resistant bacterial pathogens. PMID:22722243

  16. Evaluation of the effects of honey on acute-phase deep burn wounds.

    Science.gov (United States)

    Nakajima, Yukari; Mukai, Kanae; Nasruddin; Komatsu, Emi; Iuchi, Terumi; Kitayama, Yukie; Sugama, Junko; Nakatani, Toshio

    2013-01-01

    This study aimed to clarify the effects of honey on acute-phase deep burn wounds. Two deep burn wounds were created on mice which were divided into four groups: no treatment, silver sulfadiazine, manuka honey, and Japanese acacia honey. Wound sizes were calculated as expanded wound areas and sampled 30 minutes and 1-4 days after wounding for histological observation. The wound sections were subjected to hematoxylin and eosin and immunohistological staining to detect necrotic cells, apoptotic cells, neutrophils, and macrophages. The no treatment group formed a scar. The redness around the wound edges in the silver sulfadiazine group was the most intense. All groups exhibited increased wound areas after wounding. The proportions of necrotic cells and the numbers of neutrophils in the manuka and acacia honey groups were lower than those in the no treatment and silver sulfadiazine groups until day 3; however, there were no significant differences between all groups on day 4. These results show that honey treatment on deep burn wounds cannot prevent wound progression. Moreover, comparing our observations with those of Jackson, there are some differences between humans and animals in this regard, and the zone of hyperemia and its surrounding area fall into necrosis, which contributes to burn wound progression.

  17. Evaluation of the Effects of Honey on Acute-Phase Deep Burn Wounds

    Directory of Open Access Journals (Sweden)

    Yukari Nakajima

    2013-01-01

    Full Text Available This study aimed to clarify the effects of honey on acute-phase deep burn wounds. Two deep burn wounds were created on mice which were divided into four groups: no treatment, silver sulfadiazine, manuka honey, and Japanese acacia honey. Wound sizes were calculated as expanded wound areas and sampled 30 minutes and 1–4 days after wounding for histological observation. The wound sections were subjected to hematoxylin and eosin and immunohistological staining to detect necrotic cells, apoptotic cells, neutrophils, and macrophages. The no treatment group formed a scar. The redness around the wound edges in the silver sulfadiazine group was the most intense. All groups exhibited increased wound areas after wounding. The proportions of necrotic cells and the numbers of neutrophils in the manuka and acacia honey groups were lower than those in the no treatment and silver sulfadiazine groups until day 3; however, there were no significant differences between all groups on day 4. These results show that honey treatment on deep burn wounds cannot prevent wound progression. Moreover, comparing our observations with those of Jackson, there are some differences between humans and animals in this regard, and the zone of hyperemia and its surrounding area fall into necrosis, which contributes to burn wound progression.

  18. The accelerating effect of chitosan-silica hybrid dressing materials on the early phase of wound healing.

    Science.gov (United States)

    Park, Ji-Ung; Jung, Hyun-Do; Song, Eun-Ho; Choi, Tae-Hyun; Kim, Hyoun-Ee; Song, Juha; Kim, Sukwha

    2017-10-01

    Commercialized dressing materials with or without silver have played a passive role in early-phase wound healing, protecting the skin defects from infections, absorbing exudate, and preventing dehydration. Chitosan (CTS)-based sponges have been developed in pure or hybrid forms for accelerating wound healing, but their wound-healing capabilities have not been extensively compared with widely used commercial dressing materials, providing limited information in a practical aspect. In this study, we have developed CTS-silica (CTS-Si) hybrid sponges with water absorption, flexibility, and mechanical behavior similar to those of CTS sponges. In vitro and in vivo tests were performed to compare the CTS-Si sponges with three commercial dressing materials [gauze, polyurethane (PU), and silver-containing hydrofiber (HF-Ag)] in addition to CTS sponges. Both in vitro and in vivo tests showed that CTS-Si sponges promoted fibroblast proliferation, leading to accelerated collagen synthesis, whereas the CTS sponges did not exhibit significant differences in fibroblast proliferation and collagen synthesis from gauze, PU, and HF-Ag sponges. In case of CTS-Si, the inflammatory cells were actively recruited to the wound by the influence of the released silicon ions from CTS-Si sponges, which, in return, led to an enhanced secretion of growth factors, particularly TGF-β during the early stage. The higher level of TGF-β likely improved the proliferation of fibroblasts, and as a result, collagen synthesis by fibroblasts became remarkably productive, thereby increasing collagen density at the wound site. Therefore, the CTS-Si hybrid sponges have considerable potential as a wound-dressing material for accelerating wound healing. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1828-1839, 2017. © 2016 Wiley Periodicals, Inc.

  19. A ratiometric nanoprobe based on silver nanoclusters and carbon dots for the fluorescent detection of biothiols

    Science.gov (United States)

    Zhang, Shuming; Lin, Bixia; Yu, Ying; Cao, Yujuan; Guo, Manli; Shui, Lingling

    2018-04-01

    Ratiometric fluorescent probes could eliminate the influence from experimental factors and improve the detection accuracy. In this article, a ratiometric nanoprobe was constructed based on silver nanoclusters (AgNCs) with nitrogen-doped carbon dots (NCDs) and used for the detection of biothiols. The fluorescence peak of AgNCs was observed at 650 nm with excitation wavelength at 370 nm. In order to construct the ratiometric fluorescent probe, NCDs with the excitation and emission wavelengths at 370 nm and 450 nm were selected. After adding AgNCs, the fluorescence of NCDs was quenched. The mechanism of the fluorescence quenching was studied by fluorescence, UV-Vis absorption and the fluorescence lifetime spectra. The results indicated that the quenching could be ascribed to the inner filter effect (IFE). With the addition of biothiols, the fluorescence of AgNCs at 650 nm decreased due to the breakdown of AgNCs, and the fluorescence of NCDs at 450 nm recovered accordingly. Thus, the relationship between the ratio of the fluorescence intensities (I450/I650) and biothiol concentration was used to establish the determination method for biothiols. Cysteine (Cys) was taken as the model of biothiols, and the working curve for Cys was I450/I650 = 0.60CCys - 1.86 (CCys: μmol/L) with the detection limit of 0.14 μmol/L (S/N = 3). Then, the method was used for the detection of Cys in human urine and serum samples with satisfactory accuracy and recovery ratios. Furthermore, the probe could be applied for the visual semi-quantitative determination of Cys by naked eyes.

  20. Silver nanoplates-based colorimetric iodide recognition and sensing using sodium thiosulfate as a sensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Xinyan; Chen, Shu, E-mail: chenshumail@gmail.com; Tang, Jian; Xiong, Yuan; Long, Yunfei, E-mail: l_yunfei927@163.com

    2014-05-01

    Highlights: • A new colorimetric iodide detection strategy based on triangular Ag nanoplate. • Sodium thiosulfate performed as a sensitizer. • Formation of insoluble AgI on the surface of Ag nanoplate. • This method has the advantages of good selectivity and high sensitivity. Abstract: A colorimetric method for the recognition and sensing of iodide ions (I⁻) has been developed by utilizing the reactions between triangular silver nanoplates (TAg-NPs) and I⁻ in the presence of sodium thiosulfate (Na₂S₂O₃). Specifically, I⁻ together with Na₂S₂O₃ can induce protection of TAg-NPs owing to the formation of insoluble AgI, as confirmed by the high-resolution transmission electron microscopy (HRTEM). In the absence of Na₂S₂O₃, the etching reactions on TAg-NPs were observed not only by I⁻ but also other halides ions. The Na₂S₂O₃ plays as a sensitizer in this system, which improved the selectivity and sensitivity. The desired colorimetric detection can be achieved by measuring the change of the absorption peak wavelength corresponding to localized surface plasmon resonance (LSPR) with UV–vis spectrophotometer or recognized by naked eye observation. The results show that the shift of the maximum absorption wavelength (Δλ) of the TAg-NPs/Na₂S₂O₃/I⁻ mixture was proportional to the concentration of I⁻ in the range 1.0 × 10⁻⁹–1.0 × 10⁻⁶ mol L⁻¹. Moreover, no other ions besides I⁻ can induce an eye discernible color change as low as 1.0 × 10⁻⁷ mol L⁻¹. Finally, this method was successfully applied for I⁻ determination in kelp samples.

  1. Highly sensitive detection of bovine serum albumin based on the aggregation of triangular silver nanoplates

    Science.gov (United States)

    Zhang, Ling Ling; Ma, Fang Fang; Kuang, Yang Fang; Cheng, Shu; Long, Yun Fei; Xiao, Qiu Guo

    2016-02-01

    A simple, fast and highly sensitive spectrophotometric method for the determination of bovine serum albumin (BSA) has been developed based on the interactions between triangular silver nanoplates (TAgNPs) and BSA in the presence of Britton-Robison buffer solution (BR). Particularly, the wavelength of absorption maximum (λmax) of TAgNPs is red shifted in the presence of BSA together with Britton-Robinson buffer solution (BR, pH = 2.56), and the color of the solution changed from blue to light blue. This may be due to the interactions between BSA molecules on the surface of TAgNPs through electrostatic forces, hydrogen bonds, hydrophobic effects and van der Waals forces at pH 2.56, which leads to the aggregation of TAgNPs. The determination of BSA was achieved by measuring the change of λmax corresponding to localized surface plasmon resonance (LSPR) from UV-visible spectrophotometry. It was found that the shift value in the wavelength of absorption maximum (Δλ, the difference in absorption maxima of the TAgNPs/BSA/BR mixture and the TAgNPs/BR mixture) was proportionate to the concentration of BSA in the range of 1.0 ng mL- 1 to 100.0 ng mL- 1 with the correlation coefficient of r = 0.9969. The detection limit (3 σ/k) for BSA was found to be as low as 0.5 ng mL- 1.

  2. Transparent Electrodes Based on Silver Nanowire Networks: From Physical Considerations towards Device Integration.

    Science.gov (United States)

    Bellet, Daniel; Lagrange, Mélanie; Sannicolo, Thomas; Aghazadehchors, Sara; Nguyen, Viet Huong; Langley, Daniel P; Muñoz-Rojas, David; Jiménez, Carmen; Bréchet, Yves; Nguyen, Ngoc Duy

    2017-05-24

    The past few years have seen a considerable amount of research devoted to nanostructured transparent conducting materials (TCM), which play a pivotal role in many modern devices such as solar cells, flexible light-emitting devices, touch screens, electromagnetic devices, and flexible transparent thin film heaters. Currently, the most commonly used TCM for such applications (ITO: Indium Tin oxide) suffers from two major drawbacks: brittleness and indium scarcity. Among emerging transparent electrodes, silver nanowire (AgNW) networks appear to be a promising substitute to ITO since such electrically percolating networks exhibit excellent properties with sheet resistance lower than 10 Ω/sq and optical transparency of 90%, fulfilling the requirements of most applications. In addition, AgNW networks also exhibit very good mechanical flexibility. The fabrication of these electrodes involves low-temperature processing steps and scalable methods, thus making them appropriate for future use as low-cost transparent electrodes in flexible electronic devices. This contribution aims to briefly present the main properties of AgNW based transparent electrodes as well as some considerations relating to their efficient integration in devices. The influence of network density, nanowire sizes, and post treatments on the properties of AgNW networks will also be evaluated. In addition to a general overview of AgNW networks, we focus on two important aspects: (i) network instabilities as well as an efficient Atomic Layer Deposition (ALD) coating which clearly enhances AgNW network stability and (ii) modelling to better understand the physical properties of these networks.

  3. Aptamer-conjugated silver nanoparticles for electrochemical dual-aptamer-based sandwich detection of staphylococcus aureus.

    Science.gov (United States)

    Abbaspour, Abdolkarim; Norouz-Sarvestani, Fatemeh; Noori, Abolhassan; Soltani, Noushin

    2015-06-15

    Staphylococcus aureus (S. aureus) is one of the most important human pathogens and causes numerous illnesses. In this study, we report a sensitive and highly selective dual-aptamer-based sandwich immunosensor for the detection of S. aureus. In this bioassay system, a biotinylated primary anti-S.aureus aptamer was immobilized on streptavidin coated magnetic beads (MB), which serves as a capture probe. A secondary anti-S.aureus aptamer was conjugated to silver nanoparticles (Apt-AgNP) that sensitively reports the detection of the target. In the presence of target bacterium, an Apt/S.aureus/apt-AgNP sandwich complex is formed on the MB surface and the electrochemical signal of AgNPs followed through anodic stripping voltammetry. The proposed sandwich assay benefits from advantageous of a sandwich assay for increased specificity, MB as carriers of affinity ligands for solution-phase recognition and fast magnetic separation, AgNPs for signal amplification, and an electrochemical stripping voltammetry read-out as a simple and sensitive detection. The electrochemical immunosensor shows an extended dynamic range from 10 to 1×10(6) cfu/mL with a low detection limit of 1.0 cfu/mL (S/N=3). Furthermore, the possible interference of other analog bacteria was studied. To assess the general applicability of this sensor, we investigated the quantification of S. aureus in real water samples. The results were compared to the experimental results obtained from a plate counting method, which demonstrated an acceptable consistency. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Flow electrochemical biosensors based on enzymatic porous reactor and tubular detector of silver solid amalgam

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Bohdan; Barek, J.; Josypčuk, Oksana

    2013-01-01

    Roč. 778, MAY 2013 (2013), s. 24-30 ISSN 0003-2670 R&D Projects: GA ČR GAP206/11/1638 Institutional support: RVO:61388955 Keywords : flow analysis * amperometry * silver solid amalgam Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.517, year: 2013

  5. A novel paste electrode based on a silver solid amalgam and an organic pasting liquid

    Czech Academy of Sciences Publication Activity Database

    Daňhel, A.; Josypčuk, Bohdan; Vyskočil, V.; Zima, J.; Barek, J.

    2011-01-01

    Roč. 656, 1-2 (2011), s. 218-222 ISSN 1572-6657 R&D Projects: GA MŠk(CZ) LC06063; GA AV ČR IAA400400806 Institutional research plan: CEZ:AV0Z40400503 Keywords : voltammetry * paste electrode * silver amalgam Subject RIV: CG - Electrochemistry Impact factor: 2.905, year: 2011

  6. Intrinsic and extrinsic resistive switching in a planar diode based on silver oxide nanoparticles

    NARCIS (Netherlands)

    Kiazadeh, A.; Gomes, H.L.; Rosa da Costa, A.M.; Moreira, J.A.; Leeuw, de D.M.; Meskers, S.C.J.

    2012-01-01

    Resistive switching is investigated in thin-film planar diodes using silver oxide nanoparticles capped in a polymer. The conduction channel is directly exposed to the ambient atmosphere. Two types of switching are observed. In air, the hysteresis loop in the current–voltage characteristics is

  7. An optical tweezer-based study of antimicrobial activity of silver ...

    Indian Academy of Sciences (India)

    This is achieved by monitoring the fluctuations of an optically trapped polystyrene bead immersed in it. Examining the changes in the fluctuation pattern of the bead with time provides an accurate characterization of the reduction in the microbial activity. Here, we report on the effect of addition of silver nanoparticles on ...

  8. Antibacterial Properties of Silver Nanoparticles Embedded on Polyelectrolyte Hydrogels Based on α-Amino Acid Residues

    Directory of Open Access Journals (Sweden)

    Mario Casolaro

    2018-05-01

    Full Text Available Polyelectrolyte hydrogels bearing l-phenylalanine (PHE, l-valine (AVA, and l-histidine (Hist residues were used as scaffolds for the formation of silver nanoparticles by reduction of Ag+ ions with NaBH4. The interaction with the metal ion allowed a prompt collapse of the swollen hydrogel, due to the neutralization reaction of basic groups present on the polymer. The imidazole nitrogen of the hydrogel with Hist demonstrated greater complexing capacity with the Ag+ ion compared to the hydrogels with carboxyl groups. The subsequent reduction to metallic silver allowed for the restoration of the hydrogel’s degree of swelling to the starting value. Transmission electron microscopy (TEM and spectroscopic analyses showed, respectively, a uniform distribution of the 15 nm spherical silver nanoparticles embedded on the hydrogel and peak optical properties around a wavelength of 400 nm due to the surface plasmonic effect. Unlike native hydrogels, the composite hydrogels containing silver nanoparticles showed good antibacterial activity as gram+/gram− bactericides, and higher antifungal activity against S. cerevisiae.

  9. Wound healing in animal models: review article

    Directory of Open Access Journals (Sweden)

    Fariba Jaffary

    2017-10-01

    Full Text Available Wound healing and reduction of its recovery time is one of the most important issues in medicine. Wound is defined as disruption of anatomy and function of normal skin. This injury could be the result of physical elements such as  surgical incision, hit or pressure cut of the skin and gunshot wound. Chemical or caustic burn is another category of wound causes that can be induced by acid or base contact irritation. Healing is a process of cellular and extracellular matrix interactions that occur in the damaged tissue. Wound healing consists of several stages including hemostasis, inflammatory phase, proliferative phase and new tissue formation which reconstructs by new collagen formation. Wounds are divided into acute and chronic types based on their healing time. Acute wounds have sudden onset and in normal individuals usually have healing process of less than 4 weeks without any residual side effects. In contrast, chronic wounds have gradual onset. Their inflammatory phase is prolonged and the healing process is stopped due to some background factors like diabetes, ischemia or local pressure. If the healing process lasts more than 4 weeks it will be classified as chronic wound. Despite major advances in the treatment of wounds, still finding effective modalities for healing wounds in the shortest possible time with the fewest side effects is a current challenge. In this review different phases of wound healing and clinical types of wound such as venous leg ulcer, diabetic foot ulcer and pressure ulcer are discussed. Also acute wound models (i.e burn wounds or incisional wound and chronic wound models (such as venous leg ulcers, diabetic foot ulcer, pressure ulcers or bedsore in laboratory animals are presented. This summary can be considered as a preliminary step to facilitate designing of more targeted and applied research in this area.

  10. Complexes of DNA bases and Watson-Crick base pairs interaction with neutral silver Agn (n = 8, 10, 12) clusters: a DFT and TDDFT study.

    Science.gov (United States)

    Srivastava, Ruby

    2018-03-01

    We study the binding of the neutral Ag n (n = 8, 10, 12) to the DNA base-adenine (A), guanine (G) and Watson-Crick -adenine-thymine, guanine-cytosine pairs. Geometries of complexes were optimized at the DFT level using the hybrid B3LYP functional. LANL2DZ effective core potential was used for silver and 6-31 + G ** was used for all other atoms. NBO charges were analyzed using the Natural population analysis. The absorption properties of Ag n -A,G/WC complexes were also studied using time-dependent density functional theory. The absorption spectra for these complexes show wavelength in the visible region. It was revealed that silver clusters interact more strongly with WC pairs than with isolated DNA complexes. Furthermore, it was found that the electronic charge transferred from silver to isolated DNA clusters are less than the electronic charge transferred from silver to the Ag n -WC complexes. The vertical ionization potential, vertical electron affinity, hardness, and electrophilicity index of Ag n -DNA/WC complexes have also been discussed.

  11. Tailoring silver nanoparticle construction using dendrimer templated silica networks

    International Nuclear Information System (INIS)

    Liu Xiaojun; Kakkar, Ashok

    2008-01-01

    We have examined the role of the internal environment of dendrimer templated silica networks in tailoring the construction of silver nanoparticle assemblies. Silica networks from which 3,5-dihydroxybenzyl alcohol based dendrimer templates have been completely removed, slowly wet with an aqueous solution of silver acetate. The latter then reacts with internal silica silanol groups, leading to chemisorption of silver ions, followed by the growth of silver oxide nanoparticles. Silica network constructed using generation 4 dendrimer contains residual dendrimer template, and mixes with aqueous silver acetate solution easily. Upon chemisorption, silver ions get photolytically reduced to silver metal under a stabilizing dendrimer environment, leading to the formation of silver metal nanoparticles

  12. Direct current force sensing device based on compressive spring, permanent magnet, and coil-wound magnetostrictive/piezoelectric laminate.

    Science.gov (United States)

    Leung, Chung Ming; Or, Siu Wing; Ho, S L

    2013-12-01

    A force sensing device capable of sensing dc (or static) compressive forces is developed based on a NAS106N stainless steel compressive spring, a sintered NdFeB permanent magnet, and a coil-wound Tb(0.3)Dy(0.7)Fe(1.92)/Pb(Zr, Ti)O3 magnetostrictive∕piezoelectric laminate. The dc compressive force sensing in the device is evaluated theoretically and experimentally and is found to originate from a unique force-induced, position-dependent, current-driven dc magnetoelectric effect. The sensitivity of the device can be increased by increasing the spring constant of the compressive spring, the size of the permanent magnet, and/or the driving current for the coil-wound laminate. Devices of low-force (20 N) and high-force (200 N) types, showing high output voltages of 262 and 128 mV peak, respectively, are demonstrated at a low driving current of 100 mA peak by using different combinations of compressive spring and permanent magnet.

  13. Estimating the wound healing ability of bioactive milk proteins using an optimized cell based assay

    DEFF Research Database (Denmark)

    Nyegaard, Steffen; Andreasen, Trine; Rasmussen, Jan Trige

    Milk contains many different proteins of which the larger constituents like the caseins and major whey constituents are well characterized. We have for some time been studying the structure and function of proteins associated with the milk fat globule membrane like lactadherin, MUC1/15, xanthine...... oxidoreductase along with minor whey constituents like osteopontin, EPV20 etc. The enterocyte migration rate is a key parameter in maintaining intestinal homeostasis and intestinal repair when recovering from infection or intestinal diseases like Crohns and ulcerative colitis. We developed a novel in vitro wound...... healing assay to determine the bioactive effects of various milk proteins using human small intestine cells grown on extracellular matrix. Silicone inserts are placed in a 96-well plate and enterocytes seeded around it, creating a monolayer with a cell free area. In current ongoing experiments, various...

  14. Development of surface plasmon resonance-based sensor for detection of silver nanoparticles in food and the environment

    NARCIS (Netherlands)

    Rebe-Raz, S.; Leontaridou, M.; Bremer, M.G.E.G.; Peters, R.J.B.; Weigel, S.

    2012-01-01

    Silver nanoparticles are recognized as effective antimicrobial agents and have been implemented in various consumer products including washing machines, refrigerators, clothing, medical devices, and food packaging. Alongside the silver nanoparticles benefits, their novel properties have raised

  15. Hydroethanolic Extract of Strychnos pseudoquina Accelerates Skin Wound Healing by Modulating the Oxidative Status and Microstructural Reorganization of Scar Tissue in Experimental Type I Diabetes

    Directory of Open Access Journals (Sweden)

    Mariáurea M. Sarandy

    2017-01-01

    Full Text Available The effect of topical application of ointment based on Strychnos pseudoquina hydroethanolic extract in the cutaneous wounds healing in diabetic rats was evaluated. Samples of S. pseudoquina were submitted to phytochemical prospection and in vitro antioxidant assay. Thirty Wistar rats were divided into 5 groups: Sal-wounds treated with 0.9% saline solution; VH-wounds treated with 0.6 g of lanolin cream (vehicle; SS-wounds treated with silver sulfadiazine cream (10 mg/g; ES5- and ES10-wounds treated with an ointment of S. pseudoquina extract, 5% and 10%, respectively. Fragments of wounds were removed for histological and biochemical analysis every 7 days during 21 days. ES showed equivalent levels per gram of extract of total phenols and flavonoids equal to 122.04 mg for TAE and 0.60 mg for RE. The chlorogenic acid was one of the major constituents. S. pseudoquina extract presented high antioxidant potential in vitro. ES5 and ES10 showed higher wound healing rate and higher amount of cells, blood vessels, and type III and I collagen. The oxidative stress markers were lower in the ES5 and ES10 groups, while the antioxidants enzymes levels were higher. Ointment based on S. pseudoquina extract promotes a fast and efficient cutaneous repair in diabetic rats.

  16. Evaluation of in vitro antibacterial effect of room curing polymethylmethacrylate material adding nano-silver base inorganic antibacterial agents

    International Nuclear Information System (INIS)

    Jia Chunli; Wang Xiaorong; Zhang Citong; Sun Shiqun; Yang Yun

    2012-01-01

    Objective: To investigate the antibacterial effect of room curing polymethylmethacrylate (PMMA) material adding nano-silver base inorganic antibacterial agent and to detect the changes of its mechanical property. Methods: Nano-silver base inorganic antibacterial agent was added to the room curing PMMA material in the range of 0.5% -3.0% at an interval of 0.5% by ball milling specimen. Antibacterial rates of the specimens were detected by film method. Bending strength, impact strength, and wear resistance of the specimens were respectively detected on electronic universal testing machine, impact test machine and friction and wear test machine. Results: The antibacterial rates of Streptococcus mutans and Candida albicans were more than 50% when antibiotics content was 1.0% . The antibacterial rates of Streptococcus mutans and Candida albicans were more than 90% when the antibiotics content was 2.5% . The three mechanical properties were increased compared with control group when the antibacterial agents were in the range of 1.0% -1.5% . Then the three mechanical properties were decreased with the increasing of antimicrobial concentration. When the antibiotics content was 2.0% , the wear resistance had significant difference compared with control group (P<0.05); when the antibiotics content was 2.5% , the bending strength and impact strength had significant difference compared with control group (P<0.05). Conclusion: The antibacterial effect of room curing PMMA adding nano-silver base inorganic antibacterial agent is ideal. The antibacterial rate is increased gradually with the increasing content of antibacterial agents. There is no significant effect on the mechanical properties of room curing PMMA material, but the antibacterial effects are satisfied when the content of antibacterial agents is 2.0% . (authors)

  17. Economic benefit of a polyacrylate-based hydrogel compared to an amorphous hydrogel in wound bed preparation of venous leg ulcers

    Directory of Open Access Journals (Sweden)

    Kaspar D

    2015-04-01

    Full Text Available Daniela Kaspar,1 Jörg Linder,1 Petra Zöllner,1 Ulrich Simon,2 Hans Smola1,31Medical Competence Centre, Paul Hartmann AG, Heidenheim, Germany; 2Scientific Computing Centre, Ulm University, Ulm, Germany; 3Department of Dermatology, University of Cologne, Cologne, GermanyObjective: To assess the cost-effectiveness of a polyacrylate (PA-based hydrogel compared to an amorphous hydrogel in wound bed preparation for venous leg ulcers.Method: A cost-effectiveness analysis was undertaken alongside a multicenter, randomized controlled trial performed in France. A total of 75 patients with venous leg ulcers extensively covered with fibrin and necrotic tissue were randomized to a PA-containing hydrogel or an amorphous hydrogel. Wounds were treated for 14 days and costs were estimated from the German payer's perspective. Medical costs included study treatment, wound treatment supply, and labor time. The clinical benefit was expressed as the number of patients with wounds >50% covered with granulation tissue within 14 days. The incremental cost-effectiveness ratio (ICER was expressed as the additional cost spent with >50% granulation tissue per day per patient within 14 days of leg ulcer care.Results: Because of individual pricing of wound dressings in hospitals, cost data were derived from the outpatient sector. A total of 33 patients were treated using the PA-based hydrogel and 37 patients using the amorphous hydrogel. The estimated total direct costs per patient and per 14 days of therapy were €306 for both treatment groups. However, with the PA-based hydrogel, 2.5 additional days with wounds covered >50% with granulation tissues were gained within 14 days of leg ulcer care compared to the comparator. The ICER was €0 per additional day spent with >50% granulation tissue.Conclusion: Although there were a greater number of dressing changes in the PA-based hydrogel treatment, the total treatment cost for 14 days of leg ulcer care was the same for both

  18. Collagen-based silver nanoparticles: Study on cell viability, skin permeation, and swelling inhibition

    Energy Technology Data Exchange (ETDEWEB)

    Saura Cardoso, Vinicius, E-mail: vscfisio@ufpi.edu.br [Research Center in Biodiversity and Biotechnology, Biotec, Campus Ministro Reis Velloso, Federal University of Piauí, UFPI, 64202020 Parnaíba, Piauí (Brazil); Physiotherapy Department, Campus Ministro Reis Velloso, Federal University of Piauí, UFPI, 64202020 Parnaíba, Piauí (Brazil); Carvalho Filgueiras, Marcelo de; Medeiros Dutra, Yago; Gomes Teles, Ramon Handerson [Physiotherapy Department, Campus Ministro Reis Velloso, Federal University of Piauí, UFPI, 64202020 Parnaíba, Piauí (Brazil); Morphology and Muscle Physiology Laboratory, LAMFIM, Campus Ministro Reis Velloso, Federal University of Piauí, UFPI, 64202020 Parnaíba, Piauí (Brazil); Rodrigues de Araújo, Alyne [Research Center in Biodiversity and Biotechnology, Biotec, Campus Ministro Reis Velloso, Federal University of Piauí, UFPI, 64202020 Parnaíba, Piauí (Brazil); Primo, Fernando Lucas [Faculdade de Ciências Farmacêuticas, UNESP, Universidade Estadual Paulista, Campus de Araraquara, Departamento de Bioprocessos e Biotecnologia, 14800903 Araraquara, São Paulo (Brazil); Mafud, Ana Carolina; Batista, Larissa Fernandes; Mascarenhas, Yvonne Primerano [Institute of Physics of São Carlos, IFSC, University of São Paulo, USP, 13566590 São Carlos, SP (Brazil); and others

    2017-05-01

    Collagen is considered the most abundant protein in the animal kingdom, comprising 30% of the total amount of proteins and 6% of the human body by weight. Studies that examine the interaction between silver nanoparticles and proteins have been highlighted in the literature in order to understand the stability of the nanoparticle system, the effects observed in biological systems, and the appearance of new chemical pharmaceutical products. The objective of this study was to analyze the behavior of silver nanoparticles stabilized with collagen (AgNPcol) and to check the skin permeation capacity and action in paw edema induced by carrageenan. AgNPcol synthesis was carried out using solutions of reducing agent sodium borohydride (NaBH{sub 4}), silver nitrate (AgNO{sub 3}) and collagen. Characterization was done by using dynamic light scattering (DLS) and X-ray diffraction (XRD) and AFM. Cellular viability testing was performed by using flow cytometry in human melanoma cancer (MV3) and murine fibroblast (L929) cells. The skin permeation study was conducted using a Franz diffusion cell, and the efficiency of AgNPcol against the formation of paw edema in mice was evaluated. The hydrodynamic diameter and zeta potential of AgNPcol were 140.7 ± 7.8 nm and 20.1 ± 0.7 mV, respectively. AgNPcol failed to induce early apoptosis, late apoptosis, and necrosis in L929 cells; however, it exhibited enhanced toxicity in cancer cells (MV3) compared to normal cells (L929). AgNPcol demonstrated increased toxicological effects in cancer MV3 cells, promoting skin permeation, and preventing paw edema. - Highlights: • Silver nanoparticles were synthesized with type I collagen (AgNPcol). • AgNPcol which was characterized by XRD and DLS. • AgNPcol exhibited enhanced toxicity in cancer cells. • The efficiency of the AgNPcol against the paw edema was evaluated.

  19. Collagen-based silver nanoparticles: Study on cell viability, skin permeation, and swelling inhibition

    International Nuclear Information System (INIS)

    Saura Cardoso, Vinicius; Carvalho Filgueiras, Marcelo de; Medeiros Dutra, Yago; Gomes Teles, Ramon Handerson; Rodrigues de Araújo, Alyne; Primo, Fernando Lucas; Mafud, Ana Carolina; Batista, Larissa Fernandes; Mascarenhas, Yvonne Primerano

    2017-01-01

    Collagen is considered the most abundant protein in the animal kingdom, comprising 30% of the total amount of proteins and 6% of the human body by weight. Studies that examine the interaction between silver nanoparticles and proteins have been highlighted in the literature in order to understand the stability of the nanoparticle system, the effects observed in biological systems, and the appearance of new chemical pharmaceutical products. The objective of this study was to analyze the behavior of silver nanoparticles stabilized with collagen (AgNPcol) and to check the skin permeation capacity and action in paw edema induced by carrageenan. AgNPcol synthesis was carried out using solutions of reducing agent sodium borohydride (NaBH 4 ), silver nitrate (AgNO 3 ) and collagen. Characterization was done by using dynamic light scattering (DLS) and X-ray diffraction (XRD) and AFM. Cellular viability testing was performed by using flow cytometry in human melanoma cancer (MV3) and murine fibroblast (L929) cells. The skin permeation study was conducted using a Franz diffusion cell, and the efficiency of AgNPcol against the formation of paw edema in mice was evaluated. The hydrodynamic diameter and zeta potential of AgNPcol were 140.7 ± 7.8 nm and 20.1 ± 0.7 mV, respectively. AgNPcol failed to induce early apoptosis, late apoptosis, and necrosis in L929 cells; however, it exhibited enhanced toxicity in cancer cells (MV3) compared to normal cells (L929). AgNPcol demonstrated increased toxicological effects in cancer MV3 cells, promoting skin permeation, and preventing paw edema. - Highlights: • Silver nanoparticles were synthesized with type I collagen (AgNPcol). • AgNPcol which was characterized by XRD and DLS. • AgNPcol exhibited enhanced toxicity in cancer cells. • The efficiency of the AgNPcol against the paw edema was evaluated.

  20. Using sub-micron silver-nanoparticle based films to counter biofilm formation by Gram-negative bacteria

    Science.gov (United States)

    Gillett, A. R.; Baxter, S. N.; Hodgson, S. D.; Smith, G. C.; Thomas, P. J.

    2018-06-01

    Composite films comprised of silver nanoparticles (AgNPs) grown using a low-cost straightforward chemical bath based method have been deposited on glass microscope slides to investigate their potential as a sacrificial antibacterial coating. The as-deposited films have been characterised using scanning electron microscopy (SEM) and optical profilometry. These suggested that the films were relatively uniform in coverage. Chemical composition of the AgNP films has been studied by using X-ray photoelectron spectroscopy (XPS). The XPS analysis indicated that the Ag was in a metallic form able to sustain plasmon behaviour, and that low levels of residual nanoparticle precursors were present. Particle size was characterised using transmission electron microscopy (TEM) which showed an average particle size of 10.6 nm. The effectiveness of the films as an antibacterial coating was tested against Escherichia coli. The AgNP film was determined to be effective in the killing of E. coli cells over a 24 h period when compared to equivalent samples that contained no silver. Of particular note was that only minimal bacterial growth was detected over the first 12 h of testing, up to 78.6 times less than the control samples, suggesting the film is very efficient at slowing initial biofilm formation. The use of AgNP based films that have been synthesised using a novel low-cost, low-temperature and highly upscalable method is demonstrated as a promising solution for the deployment of silver as an effective sacrifical antimicrobial coating to counter the formation of potentially hazardous Gram negative biofilms.

  1. Effect of Malva sylvestris cream on burn injury and wounds in rats

    Directory of Open Access Journals (Sweden)

    Ebrahim Nasiri

    2015-06-01

    Full Text Available Objectives: Burn injury is one of the most health-threatening problems in the world. Malva sylvestris (M. sylvestris flowershave a high mucilage content and are used as a remedy for cut wound and dermal infected wounds in Iranian folklore Medicine. The purpose of this study was to investigate the effect of M. sylvestris cream on the second degree burn injury in rats. Materials and Methods: Five groups of 10 rats per group were burned with hot metal plate. Animals were administrated divided as control, normal saline, standard silver sulfadiazine 1% (SSD, 5% M. sylvestris, and 10% M. sylvestris into separate groups. Wound area, percentage of wound contraction, and histological and bacteriological assessments were evaluated. Results: Wound sizes were not significantly different among groups on 1st and 3rd days after burn injury, while they were significantly different among groups after 7th day post-burn injury. The average areas of wounds on the 15th day were 7.5±2.9, 6.7±2, 10.5±1.6, 4.7±2, and 4.5±2 cm2 for base cream, normal saline, SSD, 5% M. sylvestris, and 10% M. sylvestris, respectively. The results of histology exhibited well-formed horizontally-oriented collagen fibers in MS topical treatment groups. Microorganisms existed in the SSD group were most probably Staphilococcus epidermitis and for NS group were staphylococcus saprophiteccus. Conclusion: M. sylvestris cream improved histological changes of tissue components in the process of healing when compared with SSD cream. Therefore, it can be used as a topical treatment agent for burn wound.

  2. Modern collagen wound dressings: function and purpose.

    Science.gov (United States)

    Fleck, Cynthia Ann; Simman, Richard

    2010-09-01

    Collagen, which is produced by fibroblasts, is the most abundant protein in the human body. A natural structural protein, collagen is involved in all 3 phases of the wound-healing cascade. It stimulates cellular migration and contributes to new tissue development. Because of their chemotactic properties on wound fibroblasts, collagen dressings encourage the deposition and organization of newly formed collagen, creating an environment that fosters healing. Collagen-based biomaterials stimulate and recruit specific cells, such as macrophages and fibroblasts, along the healing cascade to enhance and influence wound healing. These biomaterials can provide moisture or absorption, depending on the delivery system. Collagen dressings are easy to apply and remove and are conformable. Collagen dressings are usually formulated with bovine, avian, or porcine collagen. Oxidized regenerated cellulose, a plant-based material, has been combined with collagen to produce a dressing capable of binding to and protecting growth factors by binding and inactivating matrix metalloproteinases in the wound environment. The increased understanding of the biochemical processes involved in chronic wound healing allows the design of wound care products aimed at correcting imbalances in the wound microenvironment. Traditional advanced wound care products tend to address the wound's macroenvironment, including moist wound environment control, fluid management, and controlled transpiration of wound fluids. The newer class of biomaterials and wound-healing agents, such as collagen and growth factors, targets specific defects in the chronic wound environment. In vitro laboratory data point to the possibility that these agents benefit the wound healing process at a biochemical level. Considerable evidence has indicated that collagen-based dressings may be capable of stimulating healing by manipulating wound biochemistry.

  3. Traditional Therapies for Skin Wound Healing.

    Science.gov (United States)

    Pereira, Rúben F; Bártolo, Paulo J

    2016-05-01

    Significance: The regeneration of healthy and functional skin remains a huge challenge due to its multilayer structure and the presence of different cell types within the extracellular matrix in an organized way. Despite recent advances in wound care products, traditional therapies based on natural origin compounds, such as plant extracts, honey, and larvae, are interesting alternatives. These therapies offer new possibilities for the treatment of skin diseases, enhancing the access to the healthcare, and allowing overcoming some limitations associated to the modern products and therapies, such as the high costs, the long manufacturing times, and the increase in the bacterial resistance. This article gives a general overview about the recent advances in traditional therapies for skin wound healing, focusing on the therapeutic activity, action mechanisms, and clinical trials of the most commonly used natural compounds. New insights in the combination of traditional products with modern treatments and future challenges in the field are also highlighted. Recent Advances: Natural compounds have been used in skin wound care for many years due to their therapeutic activities, including anti-inflammatory, antimicrobial, and cell-stimulating properties. The clinical efficacy of these compounds has been investigated through in vitro and in vivo trials using both animal models and humans. Besides the important progress regarding the development of novel extraction methods, purification procedures, quality control assessment, and treatment protocols, the exact mechanisms of action, side effects, and safety of these compounds need further research. Critical Issues: The repair of skin lesions is one of the most complex biological processes in humans, occurring throughout an orchestrated cascade of overlapping biochemical and cellular events. To stimulate the regeneration process and prevent the wound to fail the healing, traditional therapies and natural products have been used

  4. Synthesis and characterization of tragacanth gum based hydrogels by radiation method for use in wound dressing application

    International Nuclear Information System (INIS)

    Singh, Baljit; Varshney, Lalit; Francis, Sanju; Rajneesh

    2017-01-01

    Keeping in view the inherent wound healing ability of tragacanth gum (TG), mucoadhesive and gel forming nature of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), in the present work, an attempt has been made to prepare the antibiotic drug ‘gentamicin’ and analgesic drug ‘lidocaine’ loaded sterile TG-PVA-PVP hydrogel dressings for care of wound infection and wound pain together. These polymers were characterized by cryo-SEM, AFM, FTIR, XRD, 13 C NMR, TGA, DSC and swelling studies. Drug release mechanism and kinetic models, network parameters and other properties like haemolysis, mucoadhesion, water vapor permeability, microbial penetration, antioxidant activities and oxygen permeability were also determined. The results showed wound fluid absorption and slow drug release ability of hydrogel films. These polymer films were found to be blood compatible, permeable to water vapor and O 2, and impermeable to microorganism. Further, the synergic effects of mucoadhesive, antimicrobial and antioxidant nature of hydrogel dressings will make them suitable candidate for wound management. - Highlights: • It is radiation formation of sterile Semi-IPN hydrogel wound dressings. • Release of lidocaine and gentamicin can take for care of wound infection and wound pain simultaneously. • Hydrogels were blood compatible and permeable to H 2 O vapor and O 2. • Release of drugs occurred through non-Fickian diffusion mechanism. • Hydrogels were mucoadhesive and antioxidant nature.

  5. Quantum dot-based local field imaging reveals plasmon-based interferometric logic in silver nanowire networks.

    Science.gov (United States)

    Wei, Hong; Li, Zhipeng; Tian, Xiaorui; Wang, Zhuoxian; Cong, Fengzi; Liu, Ning; Zhang, Shunping; Nordlander, Peter; Halas, Naomi J; Xu, Hongxing

    2011-02-09

    We show that the local electric field distribution of propagating plasmons along silver nanowires can be imaged by coating the nanowires with a layer of quantum dots, held off the surface of the nanowire by a nanoscale dielectric spacer layer. In simple networks of silver nanowires with two optical inputs, control of the optical polarization and phase of the input fields directs the guided waves to a specific nanowire output. The QD-luminescent images of these structures reveal that a complete family of phase-dependent, interferometric logic functions can be performed on these simple networks. These results show the potential for plasmonic waveguides to support compact interferometric logic operations.

  6. Synthesis and characterization of tragacanth gum based hydrogels by radiation method for use in wound dressing application

    Science.gov (United States)

    Singh, Baljit; Varshney, Lalit; Francis, Sanju; Rajneesh

    2017-06-01

    Keeping in view the inherent wound healing ability of tragacanth gum (TG), mucoadhesive and gel forming nature of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), in the present work, an attempt has been made to prepare the antibiotic drug 'gentamicin' and analgesic drug 'lidocaine' loaded sterile TG-PVA-PVP hydrogel dressings for care of wound infection and wound pain together. These polymers were characterized by cryo-SEM, AFM, FTIR, XRD, 13C NMR, TGA, DSC and swelling studies. Drug release mechanism and kinetic models, network parameters and other properties like haemolysis, mucoadhesion, water vapor permeability, microbial penetration, antioxidant activities and oxygen permeability were also determined. The results showed wound fluid absorption and slow drug release ability of hydrogel films. These polymer films were found to be blood compatible, permeable to water vapor and O2, and impermeable to microorganism. Further, the synergic effects of mucoadhesive, antimicrobial and antioxidant nature of hydrogel dressings will make them suitable candidate for wound management.

  7. Visible-infrared micro-spectrometer based on a preaggregated silver nanoparticle monolayer film and an infrared sensor card

    Science.gov (United States)

    Yang, Tao; Peng, Jing-xiao; Ho, Ho-pui; Song, Chun-yuan; Huang, Xiao-li; Zhu, Yong-yuan; Li, Xing-ao; Huang, Wei

    2018-01-01

    By using a preaggregated silver nanoparticle monolayer film and an infrared sensor card, we demonstrate a miniature spectrometer design that covers a broad wavelength range from visible to infrared with high spectral resolution. The spectral contents of an incident probe beam are reconstructed by solving a matrix equation with a smoothing simulated annealing algorithm. The proposed spectrometer offers significant advantages over current instruments that are based on Fourier transform and grating dispersion, in terms of size, resolution, spectral range, cost and reliability. The spectrometer contains three components, which are used for dispersion, frequency conversion and detection. Disordered silver nanoparticles in dispersion component reduce the fabrication complexity. An infrared sensor card in the conversion component broaden the operational spectral range of the system into visible and infrared bands. Since the CCD used in the detection component provides very large number of intensity measurements, one can reconstruct the final spectrum with high resolution. An additional feature of our algorithm for solving the matrix equation, which is suitable for reconstructing both broadband and narrowband signals, we have adopted a smoothing step based on a simulated annealing algorithm. This algorithm improve the accuracy of the spectral reconstruction.

  8. Morphology-properties relationship on nanocomposite films based on poly(styrene-block-diene-block-styrene copolymers and silver nanoparticles

    Directory of Open Access Journals (Sweden)

    2011-02-01

    Full Text Available A comparative study on the self-assembled nanostructured morphology and the rheological and mechanical properties of four different triblock copolymers, based on poly(styrene-block-diene-block-styrene and poly(styrene-block-diene-block-styrene matrices, and of their respective nanocomposites with 1 wt% silver nanoparticles, is reported in this work. In order to obtain well-dispersed nanoparticles in the block copolymer matrix, dodecanethiol was used as surfactant, showing good affinity with both nanoparticles and the polystyrene phase of the matrices as predicted by the solubility parameters calculated based on Hoftyzer and Van Krevelen theory. The block copolymer with the highest PS content shows the highest tensile modulus and tensile strength, but also the smallest elongation at break. When silver nanoparticles treated with surfactant were added to the block copolymer matrices, each system studied shows higher mechanical properties due to the good dispersion and the good interface of Ag nanoparticles in the matrices. Furthermore, it has been shown that semiempirical models such as Guth and Gold equation and Halpin-Tsai model can be used to predict the tensile modulus of the analyzed nanocomposites.

  9. Antimicrobial gelatin-based elastomer nanocomposite membrane loaded with ciprofloxacin and polymyxin B sulfate in halloysite nanotubes for wound dressing.

    Science.gov (United States)

    Shi, Rui; Niu, Yuzhao; Gong, Min; Ye, Jingjing; Tian, Wei; Zhang, Liqun

    2018-06-01

    Bacterial infection is a major problem world-wide, especially in wound treatment where it can severely prolong the healing process. In this study, a double drug co-delivery elastic antibacterial nanocomposite was developed by combining ciprofloxacin (CPX) and polymyxin B sulfate-loaded halloysite clay nanotubes (HNTs-B) into a gelatin elastomer. CPX nanoparticles which act against both gram positive and gram-negative bacterium were dispersed directly in the matrix, and polymyxin B sulfate was loaded in HNTs and then distributed into the matrix. The effect of CPX and HNTs-B content on the physical properties, cytotoxicity, fibroblast adhesion and proliferation, in vitro drug release behavior and anti-bacterial properties were systematically investigated. The ciprofloxacin crystals and HNT-B were distributed in the matrix uniformly. The HNTs in the drug loading system not only enhanced the matrix' tensile strength but also slowed down the release rate of the high dissoluble polymyxin B sulfate. When the amount of HNT in the matrix increased, the thermal stability and tensile strength also increased but the polymyxin B sulfate release rate decreased because the HNTs prevented the drug release inside. All the nanocomposites exhibited antimicrobial activity against both gram-negative and gram-positive bacteria with the dual combination of drugs released from the nanocomposites. Furthermore, this kind of gelatin-based nanocomposites possesses higher water-absorbing quality, low cytotoxicity, adaptable biodegradability and good elasticity which can satisfy the requirements for an ideal biomaterial for use in wound healing applications. Copyright © 2018. Published by Elsevier B.V.

  10. [Wound healing in the elderly].

    Science.gov (United States)

    Eming, S A; Wlaschek, M; Scharffetter-Kochanek, K

    2016-02-01

    Restoration of tissue integrity is essential for host defense and protection of the organism. The efficacy and quality of skin repair varies significantly over a person's lifetime. Whereas prenatal wound healing is characterized by regeneration and scarless healing, scarring, fibrosis, and loss of function are features of postnatal repair. In fact, aging is the prominent risk factor for chronic wounds, skin fragility, infections, comorbidities, and decreased quality of life. Current strategies for restoration of tissue integrity and wound therapy are not sufficient and require further investigation of the underlying pathomechanisms and the development of causal-based concepts.

  11. Toxicity of silver nanoparticles in monocytes and keratinocytes

    DEFF Research Database (Denmark)

    Orłowski, Piotr; Krzyzowska, Malgorzata; Winnicka, Anna

    2012-01-01

    Silver nanoparticles are of interest to be used as antimicrobial agents in wound dressings and coatings in medical devices, but potential adverse effects have been reported in the literature. The possible local inflammatory response to silver nanoparticles and the role of cell death in determining...... these effects are largely unknown. Effects of the mixture of silver nanoparticles of different sizes were compared in in vitro assays for cytotoxicity, caspase-1 and caspase-9 activity and bax expression. In all tested concentrations, silver nanoparticles were more toxic for RAW 264.7 monocytes than for 291.03C...... keratinocytes and induced significant caspase-1 activity and necrotic cell death. In keratinocytes, more significantly than in macrophages, silver nanoparticles led to increase of caspase-9 activity and apoptosis. These results indicate that effects of silver nanoparticles depend on the type of exposed cells...

  12. Biological sensing with surface-enhanced Raman spectroscopy (SERS) using a facile and rapid silver colloid-based synthesis technique

    Science.gov (United States)

    Smyth, C.; Mehigan, S.; Rakovich, Y. P.; Bell, S. E. J.; McCabe, E. M.

    2011-03-01

    Optical techniques towards the realisation of sensitive and selective biosensing platforms have received a considerable amount of attention in recent times. Techniques based on interferometry, surface plasmon resonance, field-effect transistors and waveguides have all proved popular, and in particular, spectroscopy offers a large range of options. Raman spectroscopy has always been viewed as an information rich technique in which the vibrational frequencies reveal a lot about the structure of a compound. The issue with Raman spectroscopy has traditionally been that its rather low cross section leads to poor limits-of-detection. In response to this problem, Surface-enhanced Raman Scattering (SERS), which increases sensitivity by bringing the sample in contact with many types of enhanceing substrates, has been developed. Here we discuss a facile and rapid technique for the detection of pterins using colloidal silver suspensions. Pteridine compounds are a family of biochemicals, heterocyclic in structure, and employed in nature as components of colour pigmentation and also as facilitators for many metabolic pathways, particularly those relating to the amino acid hydroxylases. In this work, xanthopterin, isoxanthopterin and 7,8- dihydrobiopterin have been examined whilst absorbed to SERS-active silver colloids. SERS, while far more sensitive than regular Raman spectroscopy, has its own issues relating to the reproducibility of substrates. In order to obtain quantitative data for the pteridine compounds mentioned above, exploratory studies of methods for introducing an internal standard for normalisation of the signals have been carried out.e

  13. High performance flexible metal oxide/silver nanowire based transparent conductive films by a scalable lamination-assisted solution method

    Directory of Open Access Journals (Sweden)

    Hua Yu

    2017-03-01

    Full Text Available Flexible MoO3/silver nanowire (AgNW/MoO3/TiO2/Epoxy electrodes with comparable performance to ITO were fabricated by a scalable solution-processed method with lamination assistance for transparent and conductive applications. Silver nanoparticle-based electrodes were also prepared for comparison. Using a simple spin-coating and lamination-assisted planarization method, a full solution-based approach allows preparation of AgNW-based composite electrodes at temperatures as low as 140 °C. The resulting flexible AgNW-based electrodes exhibit higher transmittance of 82% at 550 nm and lower sheet resistance about 12–15 Ω sq−1, in comparison with the values of 68% and 22–25 Ω sq−1 separately for AgNP based electrodes. Scanning electron microscopy (SEM and Atomic force microscopy (AFM reveals that the multi-stacked metal-oxide layers embedded with the AgNWs possess lower surface roughness (<15 nm. The AgNW/MoO3 composite network could enhance the charge transport and collection efficiency by broadening the lateral conduction range due to the built of an efficient charge transport network with long-sized nanowire. In consideration of the manufacturing cost, the lamination-assisted solution-processed method is cost-effective and scalable, which is desire for large-area fabrication. While in view of the materials cost and comparable performance, this AgNW-based transparent and conductive electrodes is potential as an alternative to ITO for various optoelectronic applications.

  14. Silver linings.

    Science.gov (United States)

    Bultas, Margaret W; Pohlman, Shawn

    2014-01-01

    The purpose of this interpretive phenomenological study was to gain a better understanding of the experiences of 11 mothers of preschool children with autism spectrum disorder (ASD). Mothers were interviewed three times over a 6 week period. Interviews were analyzed using interpretive methods. This manuscript highlights one particular theme-a positive perspective mothers described as the "silver lining." This "silver lining" represents optimism despite the adversities associated with parenting a child with ASD. A deeper understanding of this side of mothering children with ASD may help health care providers improve rapport, communication, and result in more authentic family centered care. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Psoriasis and wound healing outcomes: A retrospective cohort study examining wound complications and antibiotic use.

    Science.gov (United States)

    Young, Paulina M; Parsi, Kory K; Schupp, Clayton W; Armstrong, April W

    2017-11-15

    Little is known about wound healing in psoriasis. We performed a cohort study examining differences in wound healing complications between patients with and without psoriasis. Psoriasis patients with traumatic wounds were matched 1:3 to non-psoriasis patients with traumatic wounds based on age, gender, and body mass index (BMI). We examined theincidence of wound complications including infection, necrosis, and hematoma as well as incident antibiotic use within three months following diagnosis of a traumatic wound. The study included 164 patients with traumatic wounds, comprised of 41 patients with psoriasis matched to 123 patients without psoriasis. No statistically significant differences were detected in the incidence of overall wound complications between wound patients with psoriasis and wound patients without psoriasis (14.6% versus. 13.0%, HR 1.18, CI 0.39-3.56). After adjustment for diabetes, peripheral vascular disease, and smoking, no statistically significant differences were detected in the incidence of overall wound complications between patients with and without psoriasis (HR 1.11, CI 0.34-3.58). Specifically, the adjusted rates of antibiotic use were not significantly different between those with and without psoriasis (HR 0.65, CI 0.29-1.46). The incidence of wound complications following traumatic wounds of the skin was found to be similar between patients with and without psoriasis.

  16. Laser capture microdissection-based in vivo genomic profiling of wound keratinocytes identifies similarities and differences to squamous cell carcinoma

    DEFF Research Database (Denmark)

    Pedersen, Tanja Xenia; Leethanakul, Chidchanop; Patel, Vyomesh

    2003-01-01

    keratinocytes from incisional mouse skin wounds and adjacent normal skin keratinocytes. Changes in gene expression were determined by comparative cDNA array analyses, and the approach was validated by in situ hybridization. The analyses identified 48 candidate genes not previously associated with wound...... reepithelialization. Furthermore, the analyses revealed that the phenotypic resemblance of wound keratinocytes to squamous cell carcinoma is mimicked at the level of gene expression, but notable differences between the two tissue-remodeling processes were also observed. The combination of laser capture...

  17. Oral toxicity of silver ions, silver nanoparticles and colloidal silver – a review

    DEFF Research Database (Denmark)

    Hadrup, Niels; Lam, Henrik Rye

    2014-01-01

    Orally administered silver has been described to be absorbed in a range of 0.4-18% in mammals with a human value of 18%. Based on findings in animals, silver seems to be distributed to all of the organs investigated, with the highest levels being observed in the intestine and stomach. In the skin......, silver induces a blue-grey discoloration termed argyria. Excretion occurs via the bile and urine. The following dose-dependent animal toxicity findings have been reported: death, weight loss, hypoactivity, altered neurotransmitter levels, altered liver enzymes, altered blood values, enlarged hearts...... and immunological effects. Substantial evidence exists suggesting that the effects induced by particulate silver are mediated via silver ions that are released from the particle surface. With the current data regarding toxicity and average human dietary exposure, a Margin of Safety calculation indicates at least...

  18. Healing wounds - radiation processing technology for hydrogel dressing

    International Nuclear Information System (INIS)

    Varshney, Lalit

    2009-01-01

    Uses of hydrogels are known and have several applications in medical field. Drug delivery devices, contact lenses, wound dressing, artificial cartilage's or membranes, vascular prosthesis, gel coated catheters etc., are some of the examples. Due to direct relevance to human health, scientists have been continuously exploring these systems. Generally, hydro (water) gels contain 30-90% of water entrapped in a three dimensional network structure of a hydrophilic polymer. The large water content makes them highly bio-compatible and therefore preferred for use as biomaterials. Some of the hydrophilic polymers used in these applications include poly (vinyl pyrrolidone), poly (ethylene oxide), poly (vinyl alcohol) and poly (acrylic acid ). Depending upon the nature of application, the size of these hydrogel can vary from nanometers (nanogels, injectable hydrogels) to centimeters to meters (wound dressing, fire blankets, drug delivery devices and implants). BARC hydrogel dressings have been so far used for treating burns, leprosy ulcers, animal bites, diabetic foot ulcers, herpes, fresh scars, bullet injuries, boils, pimples, sun burns, abrasion, surgical wounds of breast cancer, as bolus for radiation therapy in cancer etc. The use of gels have shown excellent result in diabetic ulcers which definitely provides an alternate to expensive biotech products and relief to expanding population of diabetics in India. Its application and some of the examples are shown in the paper. Other hydrogel based products which are under development in the authors laboratory are radiation processed silver nano-particle hydrogels to treat infected wounds and fire blankets for whole body coverage for protection from fire for defense personnel and fire service people

  19. Antimicrobial Effectiveness of Cellulose based Fabrics treated with Silver Nitrate Solution using Plasma Processes

    Directory of Open Access Journals (Sweden)

    Jelena Peran

    2017-12-01

    Full Text Available In order to obtain antibacterial properties, the possibility of deposition of silver particles from silver nitrate (AgNO3 solutions by plasma deposition process using argon as a carrier gas (PDP-Ar was explored. Hexamethyldisiloxane and acrylic acid were used as precursors and were deposited by plasma enhanced-chemical vapor deposition (PE-CVD. The processes were carried out on lyocell and modal fbrics and antimicrobial efficacy was determined on E. coli and S. aureus using time kill assay method. The results of minimal inhibitory concentration (MIC show that higher antimicrobial efficacy on E. coli is exhibited by the solution of (AgNO3 in ethylene-glycol (0.066 μg/ml rather than in absolute ethanol (0.265 μg/ml. For S. aureus, minimal inhibitory concentrations of AgNO3 solutions in both absolute ethanol and ethylene-glycol as solvents are obtained at the same value (0.132 μg/ml. Overall, the best antibacterial eff ect for both modal and lyocell samples has been achieved against E. coli using treatments with precursors (AAC and HMDSO and Ag-NO3 in ethylene-glycol as solvent, with prolonged incubation time.

  20. Investigating the collector efficiency of silver nanofluids based direct absorption solar collectors

    International Nuclear Information System (INIS)

    Chen, Meijie; He, Yurong; Zhu, Jiaqi; Wen, Dongsheng

    2016-01-01

    Highlights: • An analysis coupled with Radiation transfer, Maxwell and Energy equation is developed. • Plasmonic Au and Ag nanofluids show better photo-thermal conversion properties. • Collector height and particle concentration exist optimum solutions for efficiency. - Abstract: A one-dimensional transient heat transfer analysis was carried out to analyze the effects of the Nanoparticle (NP) volume fraction, collector height, irradiation time, solar flux, and NP material on the collector efficiency. The numerical results were compared with the experimental results obtained by silver nanofluids to validate the model, and good agreement was obtained. The numerical results show that the collector efficiency increases as the collector height and NP volume fraction increase and then reaches a maximum value. An optimum collector height (∼10 mm) and particle concentration (∼0.03%) achieving a collector efficiency of 90% of the maximum efficiency can be obtained under the conditions used in the simulation. However, the collector efficiency decreases as the irradiation time increases owing to the increased heat loss. A high solar flux is desirable to maintain a high efficiency over a wide temperature range, which is beneficial for subsequent energy utilization. The modeling results also show silver and gold nanofluids obtain higher photothermal conversion efficiencies than the titanium dioxide nanofluid because their absorption spectra are similar to the solar radiation spectrum.

  1. Preparation of Size-Controlled Silver Nanoparticles and Chitin-Based Composites and Their Antimicrobial Activities

    Directory of Open Access Journals (Sweden)

    Vinh Quang Nguyen

    2013-01-01

    Full Text Available A simple method for the preparation of size-controlled spherical silver nanoparticles (Ag NPs was reported for their generation by autoclaving a mixture of silver-containing glass powder and glucose. The particle size is regulated by the glucose concentration, with concentrations of 0.25, 1.0, and 4.0 wt% glucose providing small (3.48±1.83 nm in diameter, medium (6.53±1.78 nm, and large (12.9±2.5 nm particles, respectively. In this study, Ag NP/chitin composites were synthesized by mixing each of these three Ag NP suspensions with a <5% deacetylated (DAc chitin powder (pH 7.0 at room temperature. The Ag NPs were homogenously dispersed and stably adsorbed onto the chitin. The Ag NP/chitin composites were obtained as yellow or brown powders. Approximately 5, 15, and 20 μg of the small, medium, and large Ag NPs, respectively, were estimated to maximally adsorb onto 1 mg of chitin. The bactericidal and antifungal activities of the Ag NP/chitin composites increased as the amount of Ag NPs in the chitin increased. Furthermore, smaller Ag NPs (per weight in the chitin composites provided higher bactericidal and anti-fungal activities.

  2. Tuning the thermal diffusivity of silver based nanofluids by controlling nanoparticle aggregation

    International Nuclear Information System (INIS)

    Agresti, Filippo; Barison, Simona; Battiston, Simone; Pagura, Cesare; Fabrizio, Monica; Colla, Laura; Fedele, Laura

    2013-01-01

    With the aim of preparing stable nanofluids for heat exchange applications and to study the effect of surfactant on the aggregation of nanoparticles and thermal diffusivity, stable silver colloids were synthesized in water by a green method, reducing AgNO 3 with fructose in the presence of poly-vinylpyrollidone (PVP) of various molecular weights. A silver nanopowder was precipitated from the colloids and re-dispersed at 4 vol% in deionized water. The Ag colloids were characterized by UV–visible spectroscopy, combined dynamic light scattering and ζ-potential measurements, and laser flash thermal diffusivity. The Ag nanopowders were characterized by scanning electron microscopy and thermal gravimetric analysis. It was found that the molecular weight of PVP strongly affects the ζ-potential and the aggregation of nanoparticles, thereby affecting the thermal diffusivity of the obtained colloids. In particular, it was observed that on increasing the molecular weight of PVP the absolute value of the ζ-potential is reduced, leading to increased aggregation of nanoparticles. A clear relation was identified between thermal diffusivity and aggregation, showing higher thermal diffusivity for nanofluids having higher aggregation. A maximum improvement of thermal diffusivity by about 12% was found for nanofluids prepared with PVP having higher molecular weight. (paper)

  3. Silsesquioxane-based hybrid nanocomposites with methacrylate units containing titania and/or silver nanoparticles as antibacterial/antifungal coatings for monumental stones

    Energy Technology Data Exchange (ETDEWEB)

    Aflori, Magdalena [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania); Simionescu, Bogdana [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania); “Costin D. Nenitescu” Centre of Organic Chemistry, 202B Splaiul Independentei, 7114 Bucharest (Romania); Bordianu, Irina-Elena; Sacarescu, Liviu; Varganici, Cristian-Dragos; Doroftei, Florica; Nicolescu, Alina [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania); Olaru, Mihaela, E-mail: olaruma@icmpp.ro [“Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi (Romania)

    2013-11-20

    Highlights: • Synthesis of nanocomposites with noble metals having high antibacterial efficiency. • Silver nanoparticles antibacterial activity for monumental stone conservation. • A high antibacterial activity while assuring good stone protection. -- Abstract: The present paper reports on the evaluation of two silsesquioxane-based hybrid nanocomposites with methacrylate units containing titania and/or silver nanoparticles aimed as antibacterial coatings for monumental stones. Sol–gel reaction of titanium isopropoxide and/or 3-(trimethoxysilyl)propyl methacrylate, in the presence of silver nitrate and a primary amine surfactant, yielded new types of hybrid nanocomposites with high antibacterial/antifungal efficacy. Different polymer behaviours regarding a frequently used monumental stone originating from Romania were evidenced through Fourier-transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) technique. Conclusions regarding the stones acid-resistant character and lower influence of salt weathering on its durability, as well as a better protective coating containing titania units were revealed.

  4. Silsesquioxane-based hybrid nanocomposites with methacrylate units containing titania and/or silver nanoparticles as antibacterial/antifungal coatings for monumental stones

    International Nuclear Information System (INIS)

    Aflori, Magdalena; Simionescu, Bogdana; Bordianu, Irina-Elena; Sacarescu, Liviu; Varganici, Cristian-Dragos; Doroftei, Florica; Nicolescu, Alina; Olaru, Mihaela

    2013-01-01

    Highlights: • Synthesis of nanocomposites with noble metals having high antibacterial efficiency. • Silver nanoparticles antibacterial activity for monumental stone conservation. • A high antibacterial activity while assuring good stone protection. -- Abstract: The present paper reports on the evaluation of two silsesquioxane-based hybrid nanocomposites with methacrylate units containing titania and/or silver nanoparticles aimed as antibacterial coatings for monumental stones. Sol–gel reaction of titanium isopropoxide and/or 3-(trimethoxysilyl)propyl methacrylate, in the presence of silver nitrate and a primary amine surfactant, yielded new types of hybrid nanocomposites with high antibacterial/antifungal efficacy. Different polymer behaviours regarding a frequently used monumental stone originating from Romania were evidenced through Fourier-transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) technique. Conclusions regarding the stones acid-resistant character and lower influence of salt weathering on its durability, as well as a better protective coating containing titania units were revealed

  5. Use of gold and silver standards based on phenol-formalde-hyde resin in assay-activation analysis of geological samples

    International Nuclear Information System (INIS)

    Aliev, A.I.; Drynkin, V.I.; Lejpunskaya, D.I.; Nedostup, T.V.

    1976-01-01

    Using standards on phenol-formaldehyde resin base for assaying-activation analysis of geological specimens for gold and silver has bee the advantage of uniformly distributing Au and Ag in spesimens and possible preparing tablets of practically any form or size. The validity and accuracy of these standards have been studied for the cases of short irradiation. Conventional point standards were used as reference standards. The experiments carried out have shown that tablet resol standards are suitable for a mass assaying-activation analysis for gold and silver at practically any concentrations

  6. Electrochemical determination of paraquat in citric fruit based on electrodeposition of silver particles onto carbon paste electrode

    OpenAIRE

    Abdelfettah Farahi; Mounia Achak; Laila El Gaini; Moulay Abderrahim El Mhammedi; Mina Bakasse

    2015-01-01

    Carbon paste electrodes (CPEs) modified with silver particles present an interesting tool in the determination of paraquat (PQ) using square wave voltammetry. Metallic silver particle deposits have been obtained via electrochemical deposition in acidic media using cyclic voltammetry. Scanning electron microscopy and X-ray diffraction measurements show that the silver particles are deposited onto carbon surfaces in aggregate form. The response of PQ with modified electrode (Ag-CPE) related to ...

  7. Pre-clinical evaluation of soybean-based wound dressings and dermal substitute formulations in pig healing and non-healing in vivo models

    Directory of Open Access Journals (Sweden)

    Rostislav V Shevchenko

    2014-10-01

    Full Text Available In the last decade, a new class of natural biomaterials derived from de-fatted soybean flour processed by either thermoset or extraction procedures has been developed. These biomaterials uniquely combine adaptability to various clinical applications to proven tissue regeneration properties. In the present work, the biomaterials were formulated either as hydrogel or as paste formulation and their potential as wound dressing material or as dermal substitute was assessed by two in vivo models in pig skin: The healing full-thickness punch biopsy model and the non-healing full-thickness polytetrafluoroethylene (PTFE chamber model. The results clearly show that collagen deposition is induced by the presence of these biomaterials. A unique pattern of early inflammatory response, eliciting neutrophils and controlling macrophage infiltration, is followed by tissue cell colonization of the wound bed with a significant deposition of collagen fibers. The study also highlighted the importance in the use of optimal formulations and appropriate handling upon implantation. In large size, non-healing wounds, wound dermis was best obtained with the paste formulation as hydrogels appeared to be too loose to ensure lasting scaffolding properties. On the contrary, packing of the granules during the application of paste reduced biomaterial degradation rate and prevent the penetration of newly vascularized tissue, thus impeding grafting of split-thickness autologous skin grafts on the dermal substitute base.

  8. Development of a Porcine Delayed Wound-Healing Model and Its Use in Testing a Novel Cell-Based Therapy

    International Nuclear Information System (INIS)

    Hadad, Ivan; Johnstone, Brian H.; Brabham, Jeffrey G.; Blanton, Matthew W.; Rogers, Pamela I.; Fellers, Cory; Solomon, James L.; Merfeld-Clauss, Stephanie; DesRosiers, Colleen M.; Dynlacht, Joseph R.; Coleman, John J.; March, Keith L.

    2010-01-01

    Purpose: A delayed full-thickness wound-healing model was developed and used for examining the capacity of adipose-derived stem cells (ASCs), either alone or in platelet-rich fibrin gels, to promote healing. Methods and Materials: Four pigs received electron beam radiation to the dorsal skin surface. Five weeks after radiation, subcutaneous fat was harvested from nonirradiated areas and processed to yield ASCs. Two weeks later, 28 to 30 full-thickness 1.5-cm 2 wounds were made in irradiated and nonirradiated skin. Wounds were treated with either saline solution, ASCs in saline solution, platelet-rich plasma (PRP) fibrin gel, ASCs in PRP, or non-autologous green fluorescence protein-labeled ASCs. Results: The single radiation dose produced a significant loss of dermal microvasculature density (75%) by 7 weeks. There was a significant difference in the rate of healing between irradiated and nonirradiated skin treated with saline solution. The ASCs in PRP-treated wounds exhibited a significant 11.2% improvement in wound healing compared with saline solution. Enhancement was dependent on the combination of ASCs and PRP, because neither ASCs nor PRP alone had an effect. Conclusions: We have created a model that simulates the clinically relevant late radiation effects of delayed wound healing. Using this model, we showed that a combination of ASCs and PRP improves the healing rates of perfusion-depleted tissues, possibly through enhancing local levels of growth factors.

  9. Development of Interleukin-2 Loaded Chitosan-Based Nanogels Using Artificial Neural Networks and Investigating the Effects on Wound Healing in Rats.

    Science.gov (United States)

    Aslan, Canan; Çelebi, Nevin; Değim, I Tuncer; Atak, Ayşegül; Özer, Çiğdem

    2017-05-01

    The aim of this study was to develop and characterize rh- IL-2 loaded chitosan-based nanogels for the healing of wound incision in rats. Nanogels were prepared using chitosan and bovine serum albumin (BSA) by ionic gelation method and high temperature application, respectively. Particle size, zeta potential, and polydispersity index were measured for characterization of nanogels. The morphology of nanogels was examined by using SEM and AFM. The IL-2 loading capacity of nanogels was determined using ELISA method. In vitro release of IL-2 from nanogels was performed using Franz diffusion cells. Artificial neural network (ANN) models were developed using selected input parameters (stirring rate, chitosan%, BSA%, TPP%) where particle size was an output parameter for IL-2 free nanogels. Wound healing effect of IL-2 loaded chitosan-TPP nanogel was evaluated by determining the malondialdehyde (MDA) and glutathione (GSH) levels of wound tissues in rats. The particle size of IL-2 loaded chitosan-TPP nanogels was found to be larger than that of IL-2 loaded BSA-based chitosan nanogels. Drug loading capacity of nanogels was found 100% ± 0.010 for both nanogels. IL-2 was released slowly after the initial burst effect. According to SEM and AFM imaging, BSA-chitosan nanogel particles were of nanometer size and presented a swelling tendency, and chitosan-TPP nanogel particles were found to be spherical and homogenously dispersed. IL-2 loaded chitosan-TPP nanogel was found suitable for improving wound healing because it decreased the MDA levels and increased the GSH levels wound tissues comparing to control group.

  10. Highly sensitive methanol chemical sensor based on undoped silver oxide nanoparticles prepared by a solution method

    International Nuclear Information System (INIS)

    Rahman, M.M.; Khan, S.B.; Asiri, A.M.; Jamal, A.; Faisal, M.

    2012-01-01

    We have prepared silver oxide nanoparticles (NPs) by a simple solution method using reducing agents in alkaline medium. The resulting NPs were characterized by UV-vis and FT-IR spectroscopy, X-ray powder diffraction, and field-emission scanning electron microscopy. They were deposited on a glassy carbon electrode to give a sensor with a fast response towards methanol in liquid phase. The sensor also displays good sensitivity and long-term stability, and enhanced electrochemical response. The calibration plot is linear (r 2 = 0.8294) over the 0.12 mM to 0.12 M methanol concentration range. The sensitivity is ∼ 2.65 μAcm -2 mM -1 , and the detection limit is 36.0 μM (at a SNR of 3). We also discuss possible future prospective uses of this metal oxide semiconductor nanomaterial in terms of chemical sensing. (author)

  11. Biogenic silver nanoparticles based on trichoderma harzianum: synthesis, characterization, toxicity evaluation and biological activity

    Science.gov (United States)

    Guilger, Mariana; Pasquoto-Stigliani, Tatiane; Bilesky-Jose, Natália; Grillo, Renato; Abhilash, P. C.; Fraceto, Leonardo Fernandes; Lima, Renata De

    2017-03-01

    White mold is an agricultural disease caused by the fungus Sclerotinia sclerotiorum, which affects important crops. There are different ways of controlling this organism, but none provides inhibition of its resistance structures (sclerotia). Nanotechnology offers promising applications in agricultural area. Here, silver nanoparticles were biogenically synthesized using the fungus Trichoderma harzianum and characterized. Cytotoxicity and genotoxicity were evaluated, and the nanoparticles were initially tested against white mold sclerotia. Their effects on soybean were also investigated with no effects observed. The nanoparticles showed potential against S. sclerotiorum, inhibiting sclerotia germination and mycelial growth. Nanoparticle characterization data indicated spherical morphology, satisfactory polydispersity and size distribution. Cytotoxicity and genotoxicity assays showed that the nanoparticles caused both the effects, although, the most toxic concentrations were above those applied for white mold control. Given the potential of the nanoparticles against S. sclerotiorum, we conclude that this study presents a first step for a new alternative in white mold control.

  12. Controlling droplet-based deposition uniformity of long silver nanowires by micrometer scale substrate patterning

    International Nuclear Information System (INIS)

    Basu, Nandita; Cross, Graham L W

    2015-01-01

    We report control of droplet-deposit uniformity of long silver nanowires suspended in solutions by microscopic influence of the liquid contact line. Substrates with microfabricated line patterns with a pitch far smaller than mean wire length lead to deposit thickness uniformity compared to unpatterned substrates. For high boiling-point solvents, two significant effects were observed: The substrate patterns suppressed coffee ring staining, and the wire deposits exhibited a common orientation lying perpendicular over top the lines. The latter result is completely distinct from previously reported substrate groove channeling effects. This work shows that microscopic influence of the droplet contact line geometry including the contact angle by altered substrate wetting allows significant and advantageous influence of deposition patterns of wire-like solutes as the drop dries. (paper)

  13. Adsorption of silver nanoparticles from aqueous solution on copper-based metal organic frameworks (HKUST-1).

    Science.gov (United States)

    Conde-González, J E; Peña-Méndez, E M; Rybáková, S; Pasán, J; Ruiz-Pérez, C; Havel, J

    2016-05-01

    Silver nanoparticles (AgNP) are emerging pollutants. The use of novel materials such as Cu-(benzene 1,3,5-tricarboxylate, BTC) Metal-Organic Framework (MOFs), for AgNP adsorption and their removal from aqueous solutions has been studied. The effect of different parameters was followed and isotherm model was suggested. MOFs adsorbed fast and efficiently AgNP in the range C0 < 10 mg L(-1), being Freundlich isotherm (R = 0.993) these data fitted to. Among studied parameters a remarkable effect of chloride on sorption was found, thus their possible interactions were considered. The high adsorption efficiency of AgNP was achieved and it was found to be very fast. The feasibility of adsorption on Cu-(BTC) was proved in spiked waters. The results showed the potential interest of new material as adsorbent for removing AgNP from environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Graphene Oxide-Based Nanocomposites Decorated with Silver Nanoparticles as an Antibacterial Agent

    Science.gov (United States)

    Jaworski, Sławomir; Wierzbicki, Mateusz; Sawosz, Ewa; Jung, Anna; Gielerak, Grzegorz; Biernat, Joanna; Jaremek, Henryk; Łojkowski, Witold; Woźniak, Bartosz; Wojnarowicz, Jacek; Stobiński, Leszek; Małolepszy, Artur; Mazurkiewicz-Pawlicka, Marta; Łojkowski, Maciej; Kurantowicz, Natalia; Chwalibog, André

    2018-04-01

    One of the most promising methods against drug-resistant bacteria can be surface-modified materials with biocidal nanoparticles and nanocomposites. Herein, we present a nanocomposite with silver nanoparticles (Ag-NPs) on the surface of graphene oxide (GO) as a novel multifunctional antibacterial and antifungal material. Ultrasonic technologies have been used as an effective method of coating polyurethane foils. Toxicity on gram-negative bacteria ( Escherichia coli), gram-positive bacteria ( Staphylococcus aureus and Staphylococcus epidermidis), and pathogenic yeast ( Candida albicans) was evaluated by analysis of cell morphology, assessment of cell viability using the PrestoBlue assay, analysis of cell membrane integrity using the lactate dehydrogenase assay, and reactive oxygen species production. Compared to Ag-NPs and GO, which have been widely used as antibacterial agents, our nanocomposite shows much higher antimicrobial efficiency toward bacteria and yeast cells.

  15. Gradient titanium and silver based carbon coatings deposited on AISI316L

    Science.gov (United States)

    Batory, Damian; Reczulska, Malgorzata Czerniak-; Kolodziejczyk, Lukasz; Szymanski, Witold

    2013-06-01

    The constantly growing market for medical implants and devices caused mainly due to a lack of proper attention attached to the physical condition as well as extreme sports and increased elderly population creates the need of new biocompatible biomaterials with controlled bioactivity and certain useful properties. According to many literature reports, regarding the modifications of variety of different biomaterials using the surface engineering techniques and their biological and physicochemical examination results, the most promising material for great spectra of medical applications seem to be carbon layers. Another issue is the interaction between the implant material and surrounding tissue. In particular cases this interface area is directly exposed to air. Abovementioned concern occurs mainly in case of the external fixations, thus they are more vulnerable to infection. Therefore a crucial role has the inhibition of bacterial adhesion that may prevent implant-associated infections, occurrence of other numerous complications and in particular cases rejection of the implant. For this reason additional features of carbon coatings like antibacterial properties seem to be desired and justified. Silver doped diamond-like carbon coatings with different Ag concentrations were prepared by hybrid RF PACVD/MS (Radio Frequency Plasma Assisted Chemical Vapor Deposition/Magnetron Sputtering) deposition technique. Physicochemical parameters like chemical composition, morphology and surface topography, hardness and adhesion were determined. Examined layers showed a uniform distribution of silver in the amorphous DLC matrix, high value of H/E ratio, good adhesion and beneficial topography which make them a perfect material for medical applications e.g. modification of implants for the external fixations.

  16. Electrochemical supercapacitor electrode material based on polyacrylic acid/polypyrrole/silver composite

    International Nuclear Information System (INIS)

    Patil, Dipali S.; Pawar, Sachin A.; Devan, Rupesh S.; Gang, Myeng Gil; Ma, Yuon-Ron; Kim, Jin Hyeok; Patil, Pramod S.

    2013-01-01

    Highlights: • Polyacrylic acid/polypyrrole/silver composite prepared by chemical polymerization method. • The presence of Ag nanoparticles on PPY spherical granules provides the least resistance path to electron. • The specific capacitance about 145 F g −1 and 226 F g −1 observed for PPY/PAA and PPY/PAA/Ag samples, respectively. • The higher specific energy 7.18 Wh kg −1 and 17.45 Wh kg −1 observed for PPY/PAA and PPY/PAA/Ag respectively at current density of 0.5 mA cm −2 . -- Abstract: In the present work, we have synthesized polypyrrole (PPY)/polyacrylic acid (PAA)/silver (Ag) composite electrodes by chemical polymerization via a simple and cost effective dip coating technique for supercapacitor application. Fourier transform-infrared, Fourier transform-Raman, X-ray photoelectron and energy dispersive X-ray spectroscopy techniques are used for the phase identification. Surface morphology of the films is examined by field emission scanning electron microscopy, which revealed granular structure for PPY, spherical interlaced granules for PPY/PAA and granules with bright spots of Ag nanoparticles for the PPY/PAA/Ag composites. The supercapacitive behavior of the electrodes is tested in three electrode system with 0.1 M H 2 SO 4 electrolyte by using cyclic voltammetery and charge discharge test. The highest specific capacitance 226 F g −1 at 10 mV s −1 and energy density of 17.45 Wh kg −1 at 0.5 mA cm −2 is obtained for the PPY/PAA/Ag composite electrodes. Present work demonstrates an easy way of improving specific capacitance of the polymer electrodes. Thus the work will open a new avenue for designing low cost high performance devices for better supercapacitors

  17. Comparison of the bacterial removal performance of silver nanoparticles and a polymer based quaternary amine functiaonalized silsesquioxane coated point-of-use ceramic water filters.

    Science.gov (United States)

    Zhang, Hongyin; Oyanedel-Craver, Vinka

    2013-09-15

    This study compares the disinfection performance of ceramic water filters impregnated with two antibacterial compounds: silver nanoparticles and a polymer based quaternary amine functiaonalized silsesquioxane (poly(trihydroxysilyl) propyldimethyloctadecyl ammonium chloride (TPA)). This study evaluated these compounds using ceramic disks manufactures with clay obtained from a ceramic filter factory located in San Mateo Ixtatan, Guatemala. Instead of using full size ceramic water filters, manufactured 6.5 cm diameter ceramic water filter disks were used. Results showed that TPA can achieve a log bacterial reduction value of 10 while silver nanoparticles reached up to 2 log reduction using a initial concentration of bacteria of 10(10)-10(11)CFU/ml. Similarly, bacterial transport demonstrated that ceramic filter disks painted with TPA achieved a bacterial log reduction value of 6.24, which is about 2 log higher than the values obtained for disks painted with silver nanoparticles (bacterial log reduction value: 4.42). The release of both disinfectants from the ceramic materials to the treated water was determined measuring the effluent concentrations in each test performed. Regarding TPA, about 3% of the total mass applied to the ceramic disks was released in the effluent over 300 min, which is slightly lower than the release percentage for silver nanoparticles (4%). This study showed that TPA provides a comparable disinfection performance than silver nanoparticles in ceramic water filter. Another advantage of using TPA is the cost as the price of TPA is considerable lower than silver nanoparticles. In spite of the use of TPA in several medical related products, there is only partial information regarding the health risk associated with the ingestion of this compound. Additional long-term toxicological information for TPA should be evaluated before its future application in ceramic water filters. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Aggregation-based colorimetric sensor for determination of prothioconazole fungicide using colloidal silver nanoparticles (AgNPs)

    Science.gov (United States)

    Ivrigh, Zahra Jafar-Nezhad; Fahimi-Kashani, Nafiseh; Hormozi-Nezhad, M. Reza

    2017-12-01

    There is a growing interest in developing high-performance sensors monitoring fungicides, due to their broadly usage and their adverse effects on humans and wildlife. In the present study, a colorimetric probe has been proposed for detection of prothioconazole based on aggregation of unmodified silver nanoparticles (AgNPs). Under optimized condition, linear relationships between the concentration of prothioconazole and the absorbance ratio of A500/A395 were found over the range of 0.01 μg·mL- 1 to 0.4 μg·mL- 1 with quantification limit as low as 1.7 ng·mL- 1. Furthermore, AgNPs color change from yellow to pink-orange in presence of prothioconazole, indicates highly sensitive naked-eye colorimetric assay for quantifying prothioconazole in real applications. The proposed approach was successfully used for the determination of prothioconazole in wheat flour and paddy water sample.

  19. Are lead-free hunting rifle bullets as effective at killing wildlife as conventional lead bullets? A comparison based on wound size and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Trinogga, Anna, E-mail: anna_trinogga@gmx.de; Fritsch, Guido; Hofer, Heribert; Krone, Oliver

    2013-01-15

    variety of threatened or endangered raptors and other members of the guild of scavengers. - Highlights: ► Wound diameters do not differ between lead-free and lead-based hunting rifle bullets. ► The size of the wound's maximum cross-sectional area does not depend on bullet material. ► Lead-free rifle bullets represent a suitable alternative to conventional bullets. ► The use of non lead bullets is appropriate to prevent lead deposit in the ecosystem.

  20. Are lead-free hunting rifle bullets as effective at killing wildlife as conventional lead bullets? A comparison based on wound size and morphology

    International Nuclear Information System (INIS)

    Trinogga, Anna; Fritsch, Guido; Hofer, Heribert; Krone, Oliver

    2013-01-01

    of threatened or endangered raptors and other members of the guild of scavengers. - Highlights: ► Wound diameters do not differ between lead-free and lead-based hunting rifle bullets. ► The size of the wound's maximum cross-sectional area does not depend on bullet material. ► Lead-free rifle bullets represent a suitable alternative to conventional bullets. ► The use of non lead bullets is appropriate to prevent lead deposit in the ecosystem

  1. Russell-Silver syndrome

    Science.gov (United States)

    Silver-Russell syndrome; Silver syndrome; RSS; Russell-Silver syndrome ... One in 10 children with this syndrome has a problem involving chromosome 7. In other people with the syndrome, it may affect chromosome 11. Most of the time, it ...

  2. Hyperbaric oxygen therapy for wound healing in diabetic rats: Varying efficacy after a clinically-based protocol.

    Directory of Open Access Journals (Sweden)

    Johan W van Neck

    Full Text Available Hyperbaric oxygen therapy (HBOT is a clinical treatment in which a patient breathes pure oxygen for a limited period of time at an increased pressure. Although this therapy has been used for decades to assist wound healing, its efficacy for many conditions is unproven and its mechanism of action is not yet fully clarified. This study investigated the effects of HBOT on wound healing using a diabetes-impaired pressure ulcer rat model. Seven weeks after streptozotocin-induced diabetes in rats (n = 55, a pressure ulcer was created on dorsal skin. Subsequently, animals received HBOT during 6 weeks following a standard clinical protocol (HBOT group with varying endpoints up to 42 days post-wounding versus controls without HBOT. Capillary venous oxygen saturation (SO2 showed a significant increase in the HBOT group on day 24; however, this increase was significant at this time point only. The quantity of hemoglobin in the micro-blood vessels (rHB showed a significant decrease in the HBOT group on days 21 and 42, and showed a trend to decrease on day 31. Blood flow in the microcirculation showed a significant increase on days 17, 21 and 31 but a significant decrease on days 24 and 28. Inflammation scoring showed significantly decreased CD68 counts in the HBOT group on day 42, but not in the early stages of wound healing. Animals in the HBOT group showed a trend for an increase in mean wound breaking strength on day 42.

  3. Signal-enhanced electrochemiluminescence immunosensor based on synergistic catalysis of nicotinamide adenine dinucleotide hydride and silver nanoparticles.

    Science.gov (United States)

    Wang, Guangjie; Jin, Feng; Dai, Nan; Zhong, Zhaoyang; Qing, Yi; Li, Mengxia; Yuan, Ruo; Wang, Dong

    2012-03-01

    A new metal-organic nanocomposite with synergistic catalysis function was prepared and developed to construct an electrochemiluminescence (ECL) immunosensor for ultrasensitive detection of tumor biomarker CA125. Silver nanoparticles (AgNPs) and nicotinamide adenine dinucleotide hydride (NADH) that can participate and catalyze the ECL reaction of Ru(bpy)(3)(2+) were employed as the metal component and the organic component to synthesize the metal-organic nanocomposite of NADH-AgNPs (NA). The novel ECL immunosensor was assembled via Ru(bpy)(3)(2+)-doped silica nanoparticles (Ru-SiO(2)) modified electrode with the NA as immune labels. First, the chitosan-suspended Ru-SiO(2) nanoparticles were cast on the gold electrode surface to immobilize the ECL probes of Ru(bpy)(3)(2+) and link gold nanoparticles. Then, the primary antibodies were loaded onto the modified electrode via the gold sulfhydryl covalent binding. After immunobinding the analytes of antigen, NA-attached secondary antibodies could be captured as a sandwich type on the electrode. Finally, based on the circularly synergistic catalysis by the silver and NADH for the solid-phase ECL of Ru(bpy)(3)(2+), the proposed immunosensor sensed the concentration of antigen. The synergistic ECL catalysis of metal-organic nanocomposite amplified response signal and pushed the detection limit down to 0.03 U ml(-1), which initiated a new ECL labeling field and has great significance for ECL immunoassays. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Sensing colorimetric approaches based on gold and silver nanoparticles aggregation: Chemical creativity behind the assay. A review

    Energy Technology Data Exchange (ETDEWEB)

    Vilela, Diana; Gonzalez, Maria Cristina [Departamento de Quimica Analitica e Ingenieria Quimica, Facultad de Quimica, Edificio Polivalente, Universidad de Alcala, Ctra. Madrid-Barcelona km 33,600, 28871 Alcala de Henares, Madrid (Spain); Escarpa, Alberto, E-mail: alberto.escarpa@uah.es [Departamento de Quimica Analitica e Ingenieria Quimica, Facultad de Quimica, Edificio Polivalente, Universidad de Alcala, Ctra. Madrid-Barcelona km 33,600, 28871 Alcala de Henares, Madrid (Spain)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer Visual detection based gold and silver nanoparticles aggregation. Black-Right-Pointing-Pointer Functionalized and non-functionalized nanoparticles. Black-Right-Pointing-Pointer High selectivity and sensitivity. Black-Right-Pointing-Pointer No complex instrumentation is required/chemical creativity for analyte detection. - Abstract: Localized surface plasmon resonance (LSPR) is one of the most remarkable features of gold nanoparticles (Au NPs) and silver nanoparticles (Ag NPs). Due to these inherent optical properties, colloidal solutions of Au and Ag NPs have high extinction coefficients and different colour in the visible region of the spectrum when they are well-spaced in comparison with when they are aggregated. Therefore, a well-designed chemical interaction between the analyte and NPs surroundings leads to a change of colour (red to blue for Au NPs and yellow to brown for Ag NPs from well-spaced to aggregated ones, respectively) allowing the visual detection of the target analyte. These approaches have exhibited an excellent analytical performance with high sensitivities due to the strong LSPR and excellent selectivity strategically driven by the interaction analyte-NPs surroundings involving mainly electrostatic and hydrogen bond interactions as well as donor-acceptor chemical reactions, among others. In addition, this kind of colorimetric assays has received considerable attention in the analytical field because of their simplicity and low cost since they do not require any expensive or complex instrumentation. As a consequence of this, detection of molecules with a high significance in the bio-medical, clinical, food safety and environmental fields including DNA, proteins and a wide spectrum of organic molecules as well as inorganic ions have been impressively reported in the most relevant literature using these assays. This timely review offers a rational vision of the main achievements yielded in the relevant

  5. Sensing colorimetric approaches based on gold and silver nanoparticles aggregation: Chemical creativity behind the assay. A review

    International Nuclear Information System (INIS)

    Vilela, Diana; González, María Cristina; Escarpa, Alberto

    2012-01-01

    Highlights: ► Visual detection based gold and silver nanoparticles aggregation. ► Functionalized and non-functionalized nanoparticles. ► High selectivity and sensitivity. ► No complex instrumentation is required/chemical creativity for analyte detection. - Abstract: Localized surface plasmon resonance (LSPR) is one of the most remarkable features of gold nanoparticles (Au NPs) and silver nanoparticles (Ag NPs). Due to these inherent optical properties, colloidal solutions of Au and Ag NPs have high extinction coefficients and different colour in the visible region of the spectrum when they are well-spaced in comparison with when they are aggregated. Therefore, a well-designed chemical interaction between the analyte and NPs surroundings leads to a change of colour (red to blue for Au NPs and yellow to brown for Ag NPs from well-spaced to aggregated ones, respectively) allowing the visual detection of the target analyte. These approaches have exhibited an excellent analytical performance with high sensitivities due to the strong LSPR and excellent selectivity strategically driven by the interaction analyte-NPs surroundings involving mainly electrostatic and hydrogen bond interactions as well as donor–acceptor chemical reactions, among others. In addition, this kind of colorimetric assays has received considerable attention in the analytical field because of their simplicity and low cost since they do not require any expensive or complex instrumentation. As a consequence of this, detection of molecules with a high significance in the bio-medical, clinical, food safety and environmental fields including DNA, proteins and a wide spectrum of organic molecules as well as inorganic ions have been impressively reported in the most relevant literature using these assays. This timely review offers a rational vision of the main achievements yielded in the relevant literature according to this exciting and creative analytical field.

  6. Pediatric wound care and management in the emergency department [digest].

    Science.gov (United States)

    Sanders, Jennifer E; Pade, Kathryn H

    2017-10-23

    Traumatic wounds and lacerations are common pediatric presenting complaints to emergency departments. Although there is a large body of literature on wound care, many emergency clinicians base management of wounds on theories and techniques that have been passed down over time. Therefore, controversial, conflicting, and unfounded recommendations are prevalent. This issue reviews evidence-based recommendations for wound care and management, including wound cleansing and irrigation, anxiolysis/sedation techniques, closure methods, and post-repair wound care. [Points & Pearls is a digest of Pediatric Emergency Medicine Practice].

  7. Reliability of Single Crystal Silver Nanowire-Based Systems: Stress Assisted Instabilities.

    Science.gov (United States)

    Ramachandramoorthy, Rajaprakash; Wang, Yanming; Aghaei, Amin; Richter, Gunther; Cai, Wei; Espinosa, Horacio D

    2017-05-23

    Time-dependent mechanical characterization of nanowires is critical to understand their long-term reliability in applications, such as flexible-electronics and touch screens. It is also of great importance to develop a theoretical framework for experimentation and analysis on the mechanics of nanowires under time-dependent loading conditions, such as stress-relaxation and fatigue. Here, we combine in situ scanning electron microscope (SEM)/transmission electron microscope (TEM) tests with atomistic and phase-field simulations to understand the deformation mechanisms of single crystal silver nanowires held under constant strain. We observe that the nanowires initially undergo stress-relaxation, where the stress reduces with time and saturates after some time period. The stress-relaxation process occurs due to the formation of few dislocations and stacking faults. Remarkably, after a few hours the nanowires rupture suddenly. The reason for this abrupt failure of the nanowire was identified as stress-assisted diffusion, using phase-field simulations. Under a large applied strain, diffusion leads to the amplification of nanowire surface perturbation at long wavelengths and the nanowire fails at the stress-concentrated thin cross-sectional regions. An analytical analysis on the competition between the elastic energy and the surface energy predicts a longer time to failure for thicker nanowires than thinner ones, consistent with our experimental observations. The measured time to failure of nanowires under cyclic loading conditions can also be explained in terms of this mechanism.

  8. Smart methanol sensor based on silver oxide-doped zinc oxide nanoparticles deposited on microchips

    International Nuclear Information System (INIS)

    Rahman, Mohammed M.; Khan, Sher Bahadar; Asiri, Abdullah M.

    2014-01-01

    We have prepared calcined silver oxide-doped zinc oxide nanoparticles (NPs) by a hydrothermal method using reducing agents in alkaline medium. The doped NPs were characterized by UV/vis, FTIR, and X-ray photoelectron spectroscopy, and by X-ray powder diffraction and field-emission scanning electron microscopy. The NPs were deposited on microchips to result in a sensor that has a fast response to methanol in the liquid phase. Features include high sensitivity, low-sample volume, reliability, reproducibility, ease of integration, long-term stability, and enhanced electrochemical responses. The calibration plot is linear (r 2  = 0.9981) over the 0.25 mmolL −1 to 0.25 molL −1 methanol concentration range. The sensitivity is ∼7.917 μA cm −2 mmolL −2 , and the detection limit is 71.0 ± 0.5 μmolL −1 at a signal-to-noise-ratio of 3. (author)

  9. Dextran-based hydrogel containing chitosan microparticles loaded with growth factors to be used in wound healing

    International Nuclear Information System (INIS)

    Ribeiro, M.P.; Morgado, P.I.; Miguel, S.P.; Coutinho, P.; Correia, I.J.

    2013-01-01

    Skin injuries are traumatic events, which are seldom accompanied by complete structural and functional restoration of the original tissue. Different strategies have been developed in order to make the wound healing process faster and less painful. In the present study in vitro and in vivo assays were carried out to evaluate the applicability of a dextran hydrogel loaded with chitosan microparticles containing epidermal and vascular endothelial growth factors, for the improvement of the wound healing process. The carriers' morphology was characterized by scanning electron microscopy. Their cytotoxicity profile and degradation by-products were evaluated through in vitro assays. In vivo experiments were also performed to evaluate their applicability for the treatment of skin burns. The wound healing process was monitored through macroscopic and histological analysis. The macroscopic analysis showed that the period for wound healing occurs in animals treated with microparticle loaded hydrogels containing growth factors that were considerably smaller than that of control groups. Moreover, the histological analysis revealed the absence of reactive or granulomatous inflammatory reaction in skin lesions. The results obtained both in vitro and in vivo disclosed that these systems and its degradation by-products are biocompatible, contributed to the re-establishment of skin architecture and can be used in a near future for the controlled delivery of other bioactive agents used in regenerative medicine. - Highlights: • Evaluation of a hydrogel loaded with microparticles containing growth factors for wound healing • In vitro and in vivo assays were performed to characterize the properties of the skin substitute. • The monitoring of the wound healing process was done by macroscopic and histological analysis

  10. Dextran-based hydrogel containing chitosan microparticles loaded with growth factors to be used in wound healing

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, M.P. [CICS-UBI, Health Sciences Research Center, Faculty of Health Sciences, University of Beira Interior, Covilhã (Portugal); UDI-IPG, Research Unit for Inland Development, Polytechnic Institute of Guarda, Guarda (Portugal); Morgado, P.I.; Miguel, S.P. [CICS-UBI, Health Sciences Research Center, Faculty of Health Sciences, University of Beira Interior, Covilhã (Portugal); Coutinho, P. [CICS-UBI, Health Sciences Research Center, Faculty of Health Sciences, University of Beira Interior, Covilhã (Portugal); UDI-IPG, Research Unit for Inland Development, Polytechnic Institute of Guarda, Guarda (Portugal); Correia, I.J., E-mail: icorreia@ubi.pt [CICS-UBI, Health Sciences Research Center, Faculty of Health Sciences, University of Beira Interior, Covilhã (Portugal)

    2013-07-01

    Skin injuries are traumatic events, which are seldom accompanied by complete structural and functional restoration of the original tissue. Different strategies have been developed in order to make the wound healing process faster and less painful. In the present study in vitro and in vivo assays were carried out to evaluate the applicability of a dextran hydrogel loaded with chitosan microparticles containing epidermal and vascular endothelial growth factors, for the improvement of the wound healing process. The carriers' morphology was characterized by scanning electron microscopy. Their cytotoxicity profile and degradation by-products were evaluated through in vitro assays. In vivo experiments were also performed to evaluate their applicability for the treatment of skin burns. The wound healing process was monitored through macroscopic and histological analysis. The macroscopic analysis showed that the period for wound healing occurs in animals treated with microparticle loaded hydrogels containing growth factors that were considerably smaller than that of control groups. Moreover, the histological analysis revealed the absence of reactive or granulomatous inflammatory reaction in skin lesions. The results obtained both in vitro and in vivo disclosed that these systems and its degradation by-products are biocompatible, contributed to the re-establishment of skin architecture and can be used in a near future for the controlled delivery of other bioactive agents used in regenerative medicine. - Highlights: • Evaluation of a hydrogel loaded with microparticles containing growth factors for wound healing • In vitro and in vivo assays were performed to characterize the properties of the skin substitute. • The monitoring of the wound healing process was done by macroscopic and histological analysis.

  11. Fabrication of large area plasmonic nanoparticle grating structure on silver halide based transmission electron microscope film and its application as a surface enhanced Raman spectroscopy substrate

    International Nuclear Information System (INIS)

    Sudheer,; Tiwari, P.; Singh, M. N.; Sinha, A. K.; Rai, V. N.; Srivastava, A. K.; Bhartiya, S.; Mukherjee, C.

    2015-01-01

    The plasmonic responses of silver nanoparticle grating structures of different periods made on silver halide based electron microscope film are investigated. Raster scan of the conventional scanning electron microscope (SEM) is used to carry out electron beam lithography for fabricating the plasmonic nanoparticle grating (PNG) structures. Morphological characterization of the PNG structures, carried out by the SEM and the atomic force microscope, indicates that the depth of the groove decreases with a decrease in the grating period. Elemental characterization performed by the energy dispersive spectroscopy and the x-ray diffraction shows the presence of nanoparticles of silver in the PNG grating. The optical characterization of the gratings shows that the localized surface plasmon resonance peak shifts from 366 to 378 nm and broadens with a decrease in grating period from 10 to 2.5 μm. The surface enhanced Raman spectroscopy of the Rhodamine-6G dye coated PNG structure shows the maximum enhancement by two orders of magnitude in comparison to the randomly distributed silver nanoparticles having similar size and shape as the PNG structure

  12. Determinants of midterm functional outcomes, wound healing, and resources used in a hospital-based limb preservation program.

    Science.gov (United States)

    Ramanan, Bala; Ahmed, Ayman; Wu, Bian; Causey, Marlin W; Gasper, Warren J; Vartanian, Shant M; Reyzelman, Alexander M; Hiramoto, Jade S; Conte, Michael S

    2017-12-01

    The objective of this study was to assess midterm functional status, wound healing, and in-hospital resource use among a prospective cohort of patients treated in a tertiary hospital, multidisciplinary Center for Limb Preservation. Data were prospectively gathered on all consecutive admissions to the Center for Limb Preservation from July 2013 to October 2014 with follow-up data collection through January 2016. Limbs were staged using the Society for Vascular Surgery Wound, Ischemia, and foot Infection (WIfI) threatened limb classification scheme at the time of hospital admission. Patients with nonatherosclerotic vascular disorders, acute limb ischemia, and trauma were excluded. The cohort included 128 patients with 157 threatened limbs; 8 limbs with unstageable disease were excluded. Mean age (±standard deviation [SD]) was 66 (±13) years, and median follow-up duration (interquartile range) was 395 (80-635) days. Fifty percent (n = 64/128) of patients were readmitted at least once, with a readmission rate of 20% within 30 days of the index admission. Mean total number of admissions per patient (±SD) was 1.9 ± 1.2, with mean (±SD) cumulative length of stay (cLOS) of 17.1 (±17.9) days. During follow-up, 25% of limbs required a vascular reintervention, and 45% developed recurrent wounds. There was no difference in the rate of readmission, vascular reintervention, or wound recurrence by initial WIfI stage (P > .05). At the end of the study period, 23 (26%) were alive and nonambulatory; in 20%, functional status was missing. On both univariate and multivariate analysis, end-stage renal disease and prior functional status predicted ability to ambulate independently (P wound healing. Direct hospital (inpatient) cost per limb saved was significantly higher in stage 4 patients (P wound healing, or wound recurrence. Patients presenting with limb-threatening conditions require significant inpatient care, have a high frequency of repeated hospitalizations, and are at

  13. Antimicrobial effects of silver zeolite, silver zirconium phosphate silicate and silver zirconium phosphate against oral microorganisms

    Institute of Scientific and Technical Information of China (English)

    Sirikamon Saengmee-anupharb; Toemsak Srikhirin; Boonyanit Thaweboon; Sroisiri Thaweboon; Taweechai Amornsakchai; Surachai Dechkunakorn; Theeralaksna Suddhasthira

    2013-01-01

    Objective: To evaluate the antimicrobial activities of silver inorganic materials, including silver zeolite (AgZ), silver zirconium phosphate silicate (AgZrPSi) and silver zirconium phosphate (AgZrP), against oral microorganisms. In line with this objective, the morphology and structure of each type of silver based powders were also investigated. Methods: The antimicrobial activities of AgZ, AgZrPSi and AgZrP were tested against Streptococcus mutans, Lactobacillus casei, Candidaalbicans and Staphylococcus aureus using disk diffusion assay as a screening test. The minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined using the modified membrane method. Scanning electron microscope and X-ray diffraction were used to investigate the morphology and structure of these silver materials. Results: All forms of silver inorganic materials could inhibit the growth of all test microorganisms. The MIC of AgZ, AgZrPSi and AgZrP was 10.0 g/L whereas MLC ranged between 10.0-60.0 g/L. In terms of morphology and structure, AgZrPSi and AgZrP had smaller sized particles (1.5-3.0 µm) and more uniformly shaped than AgZ. Conclusions: Silver inorganic materials in the form of AgZ, AgZrPSi and AgZrP had antimicrobial effects against all test oral microorganisms and those activities may be influenced by the crystal structure of carriers. These results suggest that these silver materials may be useful metals applied to oral hygiene products to provide antimicrobial activity against oral infection.

  14. The Immediate and Delayed Post-Debridement Effects on Tissue Bacterial Wound Counts of Hypochlorous Acid Versus Saline Irrigation in Chronic Wounds.

    Science.gov (United States)

    Hiebert, John M; Robson, Martin C

    2016-01-01

    Introduction: Wound debridement is considered essential in chronic wound management. Hypochlorous acid has been shown to be an effective agent in reducing wound bacterial counts in open wounds. Ultrasound-enabled wound debridement is an effective and efficient method of debridement. This study compared ultrasound irrigation with hypochlorous acid versus saline irrigation for wound debridement on pre- and postoperative wounds and determined regrowth of bacteria over 1 week period of time. Finally, the outcome of definitive wound closure of the clinically clean-appearing wounds was recorded. Methods: Seventeen consenting adult patients with chronic open wounds were randomly selected for study. The patients were randomly divided into the hypochlorous acid irrigation or saline irrigation group. All patients provided pre- and postoperative tissue samples for qualitative and quantitative bacteriology. For the time (7 days) between the debridement procedure and the definitive closure procedure, the wounds were dressed with a silver-impregnated dressing and a hydroconductive dressing. Results : Both types of irrigation in the ultrasonic system initially lowered the bacterial counts by 4 to 6 logs. However, by the time of definitive closure, the saline-irrigated wounds had bacterial counts back up to 10 5 whereas the hypochlorous acid-irrigated wounds remained at 10 2 or fewer. More than 80% of patients in the saline group had postoperative closure failure compared with 25% of patients in the hypochlorous acid group. Conclusions: Hypochlorous acid irrigation with ultrasound debridement reduced bacterial growth in chronic open wounds more efficiently than saline alone. Postoperative wound closure outcomes suggest a remarkable reduction in wound complications after wound debridement using hypochlorous acid irrigation with ultrasound versus saline alone.

  15. [Wound Ballistics – a Brief Overview].

    Science.gov (United States)

    Bolliger, Stephan A; Eggert, Sebastian; Thali, Michael J

    2016-02-03

    Wound ballistics examines the specific effect, namely the wound profile, of bullets on the body by firing at synthetic models made of ordnance gelatine, glycerin soap and synthetic bones, validated with real cases from (battlefield) surgery and forensic pathology. Wound profile refers to the penetration depth, the bullet deformation/ fragmentation, the diameter of the permanent and the temporary wound cavity. Knowing these features and the used ammunition a surgeon can rapidly assess the amount damage within a patient. The forensic pathologist can draw conclusions as to the used ammunition based on the wound profile. By measuring of the destructive capability of different ammunition types, wound ballistics lays the foundation for guidelines concerning the maximum effect of military ammunition.

  16. Preparation and cold welding of silver nanowire based transparent electrodes with optical transmittances >90% and sheet resistances ohm/sq.

    Science.gov (United States)

    Xu, Feng; Xu, Wei; Mao, Bingxin; Shen, Wenfeng; Yu, Yan; Tan, Ruiqin; Song, Weijie

    2018-02-15

    In this article, silver nanowires (AgNWs) with aspect ratios of 1000 and lengths up to 200 μm are obtained by a modified polyol approach. These very long AgNWs are then utilized to prepare transparent electrodes (TEs) displaying a transmittance of 91.3% at a sheet resistance of 8.6 ohm/sq without any post-treatment. Furthermore, we also demonstrate a process for the cold welding of Ag NWs by simply dipping the AgNWs films into CTAB solutions, resulting in a further improvement for the optoelectronic performance. After the post-treatment, the AgNW-based TEs can achieve a transmittance of 93% at a sheet resistance of 9.5 ohm/sq. In addition, the electric behaviors of AgNW-based TEs are investigated. In the bulk-like regime, for the as-prepared AgNW-based TEs, the Figure of merit (FOM), DC to optical conductivity ratio reaches up to 566.8. After the cold welding process, the DC to optical conductivity ratio can reach even higher values (631.6). In the percolative regime, the as-prepared and welded AgNW-based TEs can achieve Π (FOM with percolative-like behavior) values of 166.8 and 242.1, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Halloysite nanotubes as carriers of vancomycin in alginate-based wound dressing

    Directory of Open Access Journals (Sweden)

    Joanna Kurczewska

    2017-09-01

    Full Text Available The influence of an inorganic support – halloysite nanotubes – on the release rate and biological activity of the antibiotic encapsulated in alginate-based dressings was studied. The halloysite samples were loaded with approx. 10 wt.% of the antibiotic and then encapsulated in Alginate and Gelatin/Alginate gels. The material functionalized with aliphatic amine significantly extended the release of vancomycin from alginate-based gels as compared to that achieved when silica was used. After 24 h, the released amounts of the antibiotic immobilized at silica reached 70%, while for the drug immobilized at halloysite the released amount of vancomycin reached 44% for Alginate discs. The addition of gelatin resulted in even more prolonged sustained release of the drug. The antibiotic was released from the system with a double barrier with Higuchi kinetic model and Fickian diffusion mechanism. Only the immobilized drug encapsulated in Alginate gel demonstrated very good antimicrobial activity against various bacteria. The inhibition zones were greater than those of the standard discs for the staphylococci and enterococci bacteria tested. The addition of gelatin adversely affected the biological activity of the system. The inhibition zones were smaller than those of the reference samples. A reduction in the drug dose by half had no significant effect on changing the release rate and microbiological activity. The in vivo toxicity studies of the material with immobilized drug were carried out with Acutodesmus acuminatus and Daphnia magna. The material studied had no effect on the living organisms used in the bioassays. The proposed system with a double barrier demonstrated high storage stability.

  18. Halloysite nanotubes as carriers of vancomycin in alginate-based wound dressing.

    Science.gov (United States)

    Kurczewska, Joanna; Pecyna, Paulina; Ratajczak, Magdalena; Gajęcka, Marzena; Schroeder, Grzegorz

    2017-09-01

    The influence of an inorganic support - halloysite nanotubes - on the release rate and biological activity of the antibiotic encapsulated in alginate-based dressings was studied. The halloysite samples were loaded with approx. 10 wt.% of the antibiotic and then encapsulated in Alginate and Gelatin/Alginate gels. The material functionalized with aliphatic amine significantly extended the release of vancomycin from alginate-based gels as compared to that achieved when silica was used. After 24 h, the released amounts of the antibiotic immobilized at silica reached 70%, while for the drug immobilized at halloysite the released amount of vancomycin reached 44% for Alginate discs. The addition of gelatin resulted in even more prolonged sustained release of the drug. The antibiotic was released from the system with a double barrier with Higuchi kinetic model and Fickian diffusion mechanism. Only the immobilized drug encapsulated in Alginate gel demonstrated very good antimicrobial activity against various bacteria. The inhibition zones were greater than those of the standard discs for the staphylococci and enterococci bacteria tested. The addition of gelatin adversely affected the biological activity of the system. The inhibition zones were smaller than those of the reference samples. A reduction in the drug dose by half had no significant effect on changing the release rate and microbiological activity. The in vivo toxicity studies of the material with immobilized drug were carried out with Acutodesmus acuminatus and Daphnia magna . The material studied had no effect on the living organisms used in the bioassays. The proposed system with a double barrier demonstrated high storage stability.

  19. Development of Curcumin loaded chitosan polymer based nanoemulsion gel: In vitro, ex vivo evaluation and in vivo wound healing studies.

    Science.gov (United States)

    Thomas, Lydia; Zakir, Foziyah; Mirza, Mohd Aamir; Anwer, Md Khalid; Ahmad, Farhan Jalees; Iqbal, Zeenat

    2017-08-01

    In the present study, various nanoemulsions were prepared using Labrafac PG+Triacetin as oil, Tween 80 as a surfactant and polyethylene glycol (PEG 400) as a co-surfactant. The developed nanoemulsions (NE1-NE5) were evaluated for physicochemical characterizations and ex-vivo for skin permeation and deposition studies. The highest skin deposition was observed for NE2 with 46.07% deposition amongst all developed nanoemulsions (NE1-NE5). Optimized nanoemulsion (NE2) had vesicle size of 84.032±0.023nm, viscosity 78.23±22.2 cps, refractive index 1.404. Nanoemulsion gel were developed by incorporation of optimized nanoemulsion (NE2) into 1-3% chitosan and characterized by physical evaluation and rheological studies. Chitosan gel (2%) was found to be suitable for gelation of nanoemulsion based on its consistency, feel and ease of spreadability. The flux of nanoemulsion gel was found 68.88μg/cm 2 /h as compared to NE2 (76.05μg/cm 2 /h) is significantly lower suggesting limited skin permeation of curcumin form gel. However, the retained amount of curcumin on skin by gel formulation (980.75±88μg) is significantly higher than NE2 (771.25±67μg). Enhanced skin permeation of NE2 (46.07%) was observed when compared to nanoemulsion gel (31.25%) and plain gel (11.47%). The outcome of this study evidently points out the potential of curcumin entrapped nanoemulsion gel in wound healing. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Aerosolized antimicrobial agents based on degradable dextran nanoparticles loaded with silver carbene complexes

    KAUST Repository

    Ornelas-Megiatto, Cá tia; Shah, Parth N.; Wich, Peter R.; Cohen, Jessica L.; Tagaev, Jasur A.; Smolen, Justin A.; Wright, Brian D.; Panzner, Matthew J.; Youngs, Wiley J.; Frechet, Jean; Cannon, Carolyn L.

    2012-01-01

    Degradable acetalated dextran (Ac-DEX) nanoparticles were prepared and loaded with a hydrophobic silver carbene complex (SCC) by a single-emulsion process. The resulting particles were characterized for morphology and size distribution using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The average particle size and particle size distribution were found to be a function of the ratio of the organic phase to the surfactant containing aqueous phase with a 1:5 volume ratio of Ac-DEX CH2Cl2 (organic):PBS (aqueous) being optimal for the formulation of nanoparticles with an average size of 100 ± 40 nm and a low polydispersity. The SCC loading was found to increase with an increase in the SCC quantity in the initial feed used during particle formulation up to 30% (w/w); however, the encapsulation efficiency was observed to be the best at a feed ratio of 20% (w/w). In vitro efficacy testing of the SCC loaded Ac-DEX nanoparticles demonstrated their activity against both Gram-negative and Gram-positive bacteria; the nanoparticles inhibited the growth of every bacterial species tested. As expected, a higher concentration of drug was required to inhibit bacterial growth when the drug was encapsulated within the nanoparticle formulations compared with the free drug illustrating the desired depot release. Compared with free drug, the Ac-DEX nanoparticles were much more readily suspended in an aqueous phase and subsequently aerosolized, thus providing an effective method of pulmonary drug delivery. © 2012 American Chemical Society.

  1. Aerosolized antimicrobial agents based on degradable dextran nanoparticles loaded with silver carbene complexes.

    Science.gov (United States)

    Ornelas-Megiatto, Cátia; Shah, Parth N; Wich, Peter R; Cohen, Jessica L; Tagaev, Jasur A; Smolen, Justin A; Wright, Brian D; Panzner, Matthew J; Youngs, Wiley J; Fréchet, Jean M J; Cannon, Carolyn L

    2012-11-05

    Degradable acetalated dextran (Ac-DEX) nanoparticles were prepared and loaded with a hydrophobic silver carbene complex (SCC) by a single-emulsion process. The resulting particles were characterized for morphology and size distribution using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The average particle size and particle size distribution were found to be a function of the ratio of the organic phase to the surfactant containing aqueous phase with a 1:5 volume ratio of Ac-DEX CH(2)Cl(2) (organic):PBS (aqueous) being optimal for the formulation of nanoparticles with an average size of 100 ± 40 nm and a low polydispersity. The SCC loading was found to increase with an increase in the SCC quantity in the initial feed used during particle formulation up to 30% (w/w); however, the encapsulation efficiency was observed to be the best at a feed ratio of 20% (w/w). In vitro efficacy testing of the SCC loaded Ac-DEX nanoparticles demonstrated their activity against both Gram-negative and Gram-positive bacteria; the nanoparticles inhibited the growth of every bacterial species tested. As expected, a higher concentration of drug was required to inhibit bacterial growth when the drug was encapsulated within the nanoparticle formulations compared with the free drug illustrating the desired depot release. Compared with free drug, the Ac-DEX nanoparticles were much more readily suspended in an aqueous phase and subsequently aerosolized, thus providing an effective method of pulmonary drug delivery.

  2. Transport and solid state battery characteristic studies of silver based super ion conducting glasses

    International Nuclear Information System (INIS)

    Jayaseelan, S.; Muralidharan, P.; Venkateswarlu, M.; Satyanarayana, N.

    2005-01-01

    Silverarsenotellurite (SAT), silverphosphotellurite (SPT) and silvervanadotellurite (SVT) quaternary glass systems were prepared with various formers compositions by a melt quenching method. Glass nature, glass transition temperature (T g ) and structure of the prepared glasses were identified respectively by X-ray diffraction (XRD), differential scanning calorimetric (DSC) and Fourier transform infrared (FT-IR) technique. Electrical conductivity studies were carried out by impedance measurement in the frequency range 40 Hz to 100 KHz at different temperatures for all three sets of AgI-Ag 2 O-[TeO 2 -M 2 O 5 ] (M 2 O 5 = As 2 O 5 , P 2 O 5 , V 2 O 5 ) glasses. The high conducting compositions of SAT, SPT and SVT glass samples were fixed from the results of total conductivity (σ t ). Electronic conductivity (σ e ) studies were made on high conducting composition of each glass system by Wagner's polarization method. Total current (i t ) is due to ion and electron. Electronic current (i e ) due to electron were estimated through mobility studies. Ionic conductivity (σ i ) and ionic current (i i ) were calculated respectively using the conductivity (σ t and σ e ) and current (i t and i e ) results for the SAT, SPT and SVT glasses. Transport numbers due to ion (t i ) and electron (t e ) were calculated using the conductivity and mobility results for each glass system. The high conducting composition of the SAT, SPT and SVT glasses were used as solid electrolytes with silver metal as an anode and iodine:graphite (I:C) as a cathode for the fabrication of solid state batteries (SSBs). All the fabricated batteries were characterized by measuring the open circuit voltage (OCV) and polarization properties and estimated the batteries performances

  3. Aerosolized antimicrobial agents based on degradable dextran nanoparticles loaded with silver carbene complexes

    KAUST Repository

    Ornelas-Megiatto, Cátia

    2012-11-05

    Degradable acetalated dextran (Ac-DEX) nanoparticles were prepared and loaded with a hydrophobic silver carbene complex (SCC) by a single-emulsion process. The resulting particles were characterized for morphology and size distribution using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The average particle size and particle size distribution were found to be a function of the ratio of the organic phase to the surfactant containing aqueous phase with a 1:5 volume ratio of Ac-DEX CH2Cl2 (organic):PBS (aqueous) being optimal for the formulation of nanoparticles with an average size of 100 ± 40 nm and a low polydispersity. The SCC loading was found to increase with an increase in the SCC quantity in the initial feed used during particle formulation up to 30% (w/w); however, the encapsulation efficiency was observed to be the best at a feed ratio of 20% (w/w). In vitro efficacy testing of the SCC loaded Ac-DEX nanoparticles demonstrated their activity against both Gram-negative and Gram-positive bacteria; the nanoparticles inhibited the growth of every bacterial species tested. As expected, a higher concentration of drug was required to inhibit bacterial growth when the drug was encapsulated within the nanoparticle formulations compared with the free drug illustrating the desired depot release. Compared with free drug, the Ac-DEX nanoparticles were much more readily suspended in an aqueous phase and subsequently aerosolized, thus providing an effective method of pulmonary drug delivery. © 2012 American Chemical Society.

  4. Silver nanoparticle based surface enhanced Raman scattering spectroscopy of diabetic and normal rat pancreatic tissue under near-infrared laser excitation

    International Nuclear Information System (INIS)

    Huang, H; Shi, H; Chen, W; Yu, Y; Lin, D; Xu, Q; Feng, S; Lin, J; Huang, Z; Li, Y; Chen, R

    2013-01-01

    This paper presents the use of high spatial resolution silver nanoparticle based near-infrared surface enhanced Raman scattering (SERS) from rat pancreatic tissue to obtain biochrmical information about the tissue. A high quality SERS signal from a mixture of pancreatic tissues and silver nanoparticles can be obtained within 10 s using a Renishaw micro-Raman system. Prominent SERS bands of pancreatic tissue were assigned to known molecular vibrations, such as the vibrations of DNA bases, RNA bases, proteins and lipids. Different tissue structures of diabetic and normal rat pancreatic tissues have characteristic features in SERS spectra. This exploratory study demonstrated great potential for using SERS imaging to distinguish diabetic and normal pancreatic tissues on frozen sections without using dye labeling of functionalized binding sites. (letter)

  5. Wound Healing and Care

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Wound Healing and Care KidsHealth / For Teens / Wound Healing and ... open to heal through natural scar formation. The Healing Process Before healing begins, the body gears up ...

  6. How wounds heal

    Science.gov (United States)

    ... How puncture wounds heal; How burns heal; How pressure sores heal; How lacerations heal ... bleed. For example, burns, some puncture wounds, and pressure sores do not bleed. Once the scab forms, your ...

  7. Hyperbaric oxygen therapy for wound healing in diabetic rats: Varying efficacy after a clinically-based protocol

    NARCIS (Netherlands)

    J.W. van Neck (Han); B. Tuk (Bastiaan); E.M.G. Fijneman (Esther ); Redeker, J.J. (Jonathan J.); Talahatu, E.M. (Edwin M.); M. Tong (Miao)

    2017-01-01

    textabstractHyperbaric oxygen therapy (HBOT) is a clinical treatment in which a patient breathes pure oxygen for a limited period of time at an increased pressure. Although this therapy has been used for decades to assist wound healing, its efficacy for many conditions is unproven and its mechanism

  8. A comparison of hemorrhage control and hydrogen peroxide generation in commercial and cotton-based wound dressing materials

    Science.gov (United States)

    Nonwoven UltraCleanTM Cotton (highly cleaned and hydroentangled, greige cotton) retains the native wax and pectin content (~2%) of the cotton fiber traditionally removed from scoured and bleached cotton gauze, yet potentially affording wound healing properties. In vitro thromboelastography, hydrog...

  9. Aggregation and dissolution of silver nanoparticles in a laboratory-based freshwater microcosm under simulated environmental conditions

    CSIR Research Space (South Africa)

    Walters, Chavon R

    2014-04-01

    Full Text Available CSIR, Natural Resources and the Environment, Stellenbosch, South Africa; bDepartment of Medical Biosciences, University of the Western Cape, Bellville, South Africa Abstract Silver nanoparticles (NP) are used in several applications, including their use...

  10. Enhancing Low-Temperature and Pressureless Sintering of Micron Silver Paste Based on an Ether-Type Solvent

    Science.gov (United States)

    Zhang, Hao; Li, Wanli; Gao, Yue; Zhang, Hao; Jiu, Jinting; Suganuma, Katsuaki

    2017-08-01

    Micron silver paste enables a low-temperature and pressureless sintering process by using an ether-type solvent CELTOL-IA (C x H y O z , x > 10, boiling point of approximately 200°C) for the die attachment of high-powered devices. The conductive patterns formed by the silver paste had a low electrical resistivity of 8.45 μΩ cm at 180°C. The paste also achieved a high bonding strength above 30 MPa at 180°C without the assistance of pressures. These superior performance indicators result from the favorable removal of the solvent, its thermal behavior, and its good wetting on the silver layer. The results suggest that the micron silver paste with a suitable solvent can promote the further spreading of next-generation power devices owing to its marked cost advantage and excellent performance.

  11. Synthesis of anti-aggregation silver nanoparticles based on inositol hexakisphosphoric micelles for a stable surface enhanced Raman scattering substrate

    International Nuclear Information System (INIS)

    Wang Na; Yang Haifeng; Zhu Xuan; Zhang Rui; Wang Yao; Huang Guanfeng; Zhang Zongrang

    2009-01-01

    We report a novel method of synthesizing a kind of silver nanoparticles aided by the inositol hexakisphosphoric micelle as a soft template and stabilizer. By controlling the reaction time, UV-vis and TEM observations of the size growth of the nanoparticles are performed. Careful examinations of surface enhanced Raman scattering (SERS) spectra of 2-mercaptopyridine (2-Mpy) on the as-produced silver nanoparticles exhibit very stable and reproducible Raman signals within about 4 months.

  12. In vitro assessment of activity of graphene silver composite sheets ...

    African Journals Online (AJOL)

    Purpose: To synthesize graphene-based silver nanocomposites and evaluate their antimicrobial and anti-Tomato Bushy Stunt Virus (TBSV) activities. Methods: A graphene-based silver composite was prepared by adsorbing silver nanoparticles AgNPs to the surfaces of graphene oxide (GO) sheets. Scanning electron ...

  13. Improved wound care product

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention pertains to use of sodium diacetate (NaHAc 2) as an antimicrobial agent against bacteria growing in biofilms. The aspects of the invention include a wound care product comprising sodium diacetate, a kit comprising a wound care product,and a methodof treating an infected wound....

  14. A Clinicoepidemiological Profile of Chronic Wounds in Wound Healing Department in Shanghai.

    Science.gov (United States)

    Sun, Xiaofang; Ni, Pengwen; Wu, Minjie; Huang, Yao; Ye, Junna; Xie, Ting

    2017-03-01

    The aim of the study was to update the clinical database of chronic wounds in order to derive an evidence based understanding of the condition and hence to guide future clinical management in China. A total of 241 patients from January 1, 2011 to April 30, 2016 with chronic wounds of more than 2 weeks' duration were studied in wound healing department in Shanghai. Results revealed that among all the patients the mean age was 52.5 ± 20.2 years (range 2-92 years). The mean initial area of wounds was 30.3 ± 63.0 cm 2 (range 0.25-468 cm 2 ). The mean duration of wounds was 68.5 ± 175.2 months (range 0.5-840 months). The previously reported causes of chronic wounds were traumatic or surgical wounds (n = 82, 34.0%), followed by pressure ulcers (n = 59, 24.5%). To study the effects of age, patients were divided into 2 groups: less than 60 years (wounds etiology between the 2 age groups was analyzed, and there was significant statistical difference ( P wounds, chi-square test was used. There were significant differences in the factor of wound infection. ( P = .035, 95% CI = 0.031-0.038) Regarding therapies, 72.6% (n = 175) of the patients were treated with negative pressure wound therapy. Among all the patients, 29.9% (n = 72) of them were completely healed when discharged while 62.7% (n = 150) of them improved. The mean treatment cost was 12055.4 ± 9206.3 Chinese Yuan (range 891-63626 Chinese Yuan). In conclusion, traumatic or surgical wounds have recently become the leading cause of chronic wounds in Shanghai, China. Etiology of the 2 age groups was different. Infection could significantly influence the wound outcome.

  15. Dual-signal fenamithion probe by combining fluorescence with colorimetry based on Rhodamine B modified silver nanoparticles.

    Science.gov (United States)

    Cui, Zhimin; Han, Cuiping; Li, Haibing

    2011-04-07

    A versatile yet simple strategy for the fabrication of a highly selective and sensitive fenamithion probe based on Rhodamine B (RB) modified silver nanoparticles (RB-Ag NPs) was developed. The advantage of our system over classical assays is that it combined fluorescence with colorimetry which can realize the prompt on-site and real-time detection of fenamithion with high sensitivity (0.1 nM) in aqueous solution. Moreover, the detection system presents excellent anti-disturbance ability when exposed to a series of interfering ionic/pesticides mixtures and can be applied to the determination of fenamithion in real vegetables and different water samples with the limit of detection (LOD) as low as 10 nM (0.0026 mg L(-1)), which is in accord with the maximum contamination level of 0.001∼0.25 mg L(-1) for organophosphorus pesticides as defined by the U.S. Environmental Protection Agency (EPA). Advantage is taken of the fact that RB would be displaced from the surface of the Ag NPs because of the stronger coordination ability of Ag NPs with fenamithion, an amino-containing organophosphorus pesticide, accompanying the clustered Ag NPs (9 nm) dissipating into smaller individual particles (7 nm). Based on this phenomenon, a novel analyte-induced etching mechanism was proposed. © The Royal Society of Chemistry 2011

  16. Toxicity of silver nanoparticles in mouse embryonic stem cells and chemical based reprogramming of somatic cells to sphere cells

    Science.gov (United States)

    Rajanahalli Krishnamurthy, Pavan

    Abstract 1: Silver nanoparticles (Ag Np's) have an interesting surface chemistry and unique plasmonic properties. They are used in a wide variety of applications ranging from consumer products like socks, medical dressing, computer chips and it is also shown to have antimicrobial, anti bacterial activity and wound healing. Ag Np toxicity studies have been limited to date which needs to be critically addressed due to its wide applications. Mouse embryonic stem (MES) cells represent a unique cell population with the ability to undergo both self renewal and differentiation. They exhibit very stringent and tightly regulated mechanisms to circumvent DNA damage and stress response. We used 10 nm coated (polysaccharide) and uncoated Ag Np's to test its toxic effects on MES cells. MES cells and embryoid bodies (EB's) were treated with two concentrations of Ag Np's: 5 microg/ml and 50 ug/ml and exposed for 24, 48 and 72 hours. Increased cell death, ROS production and loss of mitochondrial membrane potential and alkaline phosphatase (AP) occur in a time and a concentration dependant manner. Due to increased cell death, there is a progressive increase in Annexin V (apoptosis) and Propidium Iodide (PI) staining (necrosis). Oct4 and Nanog undergo ubiquitination and dephosphorylation post-translational modifications in MES cells thereby altering gene expression of pluripotency factors and differentiation of EB's into all the three embryonic germ layers with specific growth factors were also inhibited after Ag Np exposure. Flow cytometry analysis revealed Ag Np's treated cells had altered cell cycle phases correlating with altered self renewal capacity. Our results suggest that Ag Np's effect MES cell self renewal, pluripotency and differentiation and serves as a perfect model system for studying toxicity induced by engineered Ag Np's. Abstract 2: The reprogramming of fibroblasts to pluripotent stem cells and the direct conversion of fibroblasts to functional neurons has been

  17. A molecular beacon based on DNA-templated silver nanoclusters for the highly sensitive and selective multiplexed detection of virulence genes.

    Science.gov (United States)

    Han, Dan; Wei, Chunying

    2018-05-01

    In this work, we develop a fluorescent molecular beacon based on the DNA-templated silver nanoclusters (DNA-Ag NCs). The skillfully designed molecular beacon can be conveniently used for detection of diverse virulence genes as long as the corresponding recognition sequences are embedded. Importantly, the constructed detection system allows simultaneous detection of multiple nucleic acids, which is attributed to non-overlapping emission spectra of the as-synthesized silver nanoclusters. Based on the target-induced fluorescence enhancement, three infectious disease-related genes HIV, H1N1, and H5N1 are detected, and the corresponding detection limits are 3.53, 0.12 and 3.95nM, respectively. This design allows specific, versatile and simultaneous detection of diverse targets with easy operation and low cost. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Anomeric 2'-Deoxycytidines and Silver Ions: Hybrid Base Pairs with Greatly Enhanced Stability and Efficient DNA Mismatch Detection with α-dC.

    Science.gov (United States)

    Guo, Xiurong; Seela, Frank

    2017-09-04

    α-d-Nucleosides are rare in nature but can develop fascinating properties when incorporated into DNA. This work reports on the first silver-mediated base pair constructed from two anomeric nucleosides: α-dC and β-dC. The hybrid base pair was integrated into the DNA and DNA/RNA double helix. A 12-mer duplex with α-dC and β-dC pair exhibits a higher thermal stability (T m =43 °C) than that incorporating the β-dC-Ag + -β-dC homo pair (T m =34 °C). Furthermore, α-dC shows excellent mismatch discrimination for DNA single nucleotide polymorphism (SNP). All four SNPs were identified on the basis of large T m value differences measured in the presence of silver ions. High resolution melting was not required. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Cyclic voltammetry, square wave voltammetry, electrochemical impedance spectroscopy and colorimetric method for hydrogen peroxide detection based on chitosan/silver nanocomposite

    Directory of Open Access Journals (Sweden)

    Hoang V. Tran

    2018-05-01

    Full Text Available In this paper, we demonstrate a promising method to fabricate a non-enzymatic stable, highly sensitive and selective hydrogen peroxide sensor based on a chitosan/silver nanoparticles (CS/AgNPs hybrid. Using this composite, we elaborated both electrochemical and colorimetric sensors for hydrogen peroxide detection. The colorimetric sensor is based on a homogenous reaction which fades the color of CS/AgNPs solutions from red-orange to colorless depending on hydrogen peroxide concentration. For the electrochemical sensor, CS/AgNPs were immobilized on glassy carbon electrodes and hydrogen peroxide was measured using cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy. The response time is less than 10 s and the detection limit is 5 μM. Keywords: Spectrophotometric detection, Electrochemical impedance spectroscopy, Square wave voltammetry, Cyclic voltammetry, Chitosan/silver nanoparticles (CS/AgNPs hybrid, Hydrogen peroxide

  20. Microscopy based studies on the interaction of bio-based silver nanoparticles with Bombyx mori Nuclear Polyhedrosis virus.

    Science.gov (United States)

    Tamilselvan, Selvaraj; Ashokkumar, Thirunavukkarasu; Govindaraju, Kasivelu

    2017-04-01

    In the present investigation, silver nanoparticles (AgNPs) interactions with Bombyx mori Nuclear Polyhedrosis virus (BmNPV) were characterized using High-Resolution Scanning Electron Microscopy (HR-SEM), Energy Dispersive X-ray Analysis (EDAX), Transmission Electron Microscopy (TEM), Atomic Force Microcopy (AFM) and Confocal Microscope (CM). HR-SEM study reveals that the biosynthesized AgNPs have interacted with BmNPV and were found on the surface. TEM micrographs of normal and viral polyhedra treated with AgNPs showed that the nanoparticles were accumulated in the membrane and it was noted that some of the AgNPs successfully penetrated the membrane by reaching the capsid of BmNPV. AFM and confocal microscopy studies reveal that the disruption in the shell membrane tends to lose its stability due to exposure of AgNPs to BmNPV. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Sol–gel-based silver nanoparticles-doped silica – Polydiphenylamine nanocomposite for micro-solid-phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Bagheri, Habib, E-mail: bagheri@sharif.edu; Banihashemi, Solmaz

    2015-07-30

    A nanocomposite of silica-polydiphenylamine doped with silver nanoparticles (Ag–SiO{sub 2}-PDPA) was successfully synthesized by the sol–gel process. For its preparation, PDPA was mixed with butanethiol capped Ag nanoparticles (NPs) and added to the silica sol solution. The Ag NPs were stabilized as a result of their adsorption on the SiO{sub 2} spheres. The surface characteristic of nanocomposite was investigated using scanning electron microscopy (SEM). In this work the Ag–SiO{sub 2}-PDPA nanocomposite was employed as an efficient sorbent for micro-solid-phase extraction (μ-SPE) of some selected pesticides. An amount of 15 mg of the prepared sorbent was used to extract and determine the representatives from organophosphorous, organochlorine and aryloxyphenoxy propionic acids from aqueous samples. After the implementation of extraction process, the analytes were desorbed by methanol and determined using gas chromatography–mass spectrometry (GC–MS). Important parameters influencing the extraction and desorption processes such as pH of sample solution, salting out effect, type and volume of the desorption solvent, the sample loading and eluting flow rates along with the sample volume were experimentally optimized. Limits of detection (LODs) and the limits of quantification (LOQs) were in the range of 0.02–0.05 μg L{sup −1} and 0.1–0.2 μg L{sup −1}, respectively, using time scheduled selected ion monitoring (SIM) mode. The relative standard deviation percent (RSD %) with four replicates was in the range of 6–10%. The applicability of the developed method was examined by analyzing different environmental water samples and the relative recovery (RR %) values for the spiked water samples were found to be in the range of 86–103%. - Highlights: • A sol–gel-based silver nanoparticles doped silica-polydiphenylamine nanocomposite was synthesized. • The sorbent was applied to micro-solid-phase extraction of some selected pesticides in water

  2. CLINICAL STUDY OF POST LAPAROTOMY WOUND DEHISCENCE

    Directory of Open Access Journals (Sweden)

    Chanda Ramanachalam

    2017-04-01

    Full Text Available BACKGROUND The aim of the study is to- 1. Assess the association and prevalence of risk factors involved in causing post laparotomy wound dehiscence. 2. Identify the type of disease involved in causing abdominal wound dehiscence. 3. Effectively manage cases of wound dehiscence. MATERIALS AND METHODS Total 50 cases clinically presenting as gaping of abdominal wound and discharge from the site during the period of October 2014 to April 2016 were taken for study. Patients presenting with abdominal wound dehiscence after undergoing elective or emergency operation Each case was examined clinically and properly in systematic manner and an elaborative study of history based on chief complaints, significant risk factors, investigations, time and type of surgery performed and postoperative events and day of onset of wound dehiscence. RESULTS Males outnumbered females with 64% males and 36% females. Patients in the age group of 41-50 years and 51-60 years found to have highest incidence of abdominal wound dehiscence. Mean age of the patients affected was 48.02 years. Incidence of abdominal wound dehiscence is more common in patients with peritonitis due to duodenal and appendicular perforation than in case of intestinal obstruction. Incidence of abdominal wound dehiscence is more common in patients who are operated in emergency than elective (35:15. Surgical procedures, which included perforation closure carried higher incidence of wound dehiscence. Patients operated with midline incision carried higher risk for wound dehiscence than those operated with paramedian incisions. Incidence of abdominal wound dehiscence is more common in patients having their BMI >25 and anaemia (Hb% <10 g%. Average stay was 22 days, which increased both economic burden on patient and hospital. Out of 50 cases, 48 survivals and 2 were mortals. Partial wound dehiscence was conservative management, i.e. healing by secondary intention was observed in 32 patients and 8 patients had

  3. Use of Ovine-based Collagen Extracellular Matrix and Gentian Violet/Methylene Blue Antibacterial Foam Dressings to Help Improve Clinical Outcomes in Lower Extremity Wounds: A Retrospective Cohort Study.

    Science.gov (United States)

    Lullove, Eric J

    2017-04-01

    Dressings that provide broad spectrum metalloprotease reduction along with inherent aspects of an extracellular matrix may contribute to improved wound healing outcomes and shorter treatment times. The author performed a retrospective case series analysis to determine the clinical outcomes of regular debridement with the use of ovine-based collagen extracellular matrix dressings and gentian violet/methylene blue polyurethane antibacterial foam dressings in treating 53 patients with 53 chronic lower extremity wounds (diabetic foot ulcers [DFUs], venous leg ulcers, and heel pressure ulcers). Patients were treated twice weekly in an outpatient clinic for the first 4 weeks and weekly thereafter until closure. Average body mass index (BMI) for the study population was 28.3, and the average patient age was 75.9 years. Mean percent wound surface area reduction at 4, 8, and 12 weeks was 38.5%, 73.3%, and 91.3%, respectively. Average time to closure for all wounds was 10.6 weeks (range, 5-24 weeks). All wounds were 100% reepithelialized by week 20 except 1 DFU that reepithelialized at week 24. The average cost of care for a single wound episode (from presentation to closure) was $2749.49. Results of this analysis showed that the healing of chronic wounds in this series could be achieved at a reasonable cost with regular debridement and a collagen matrix dressing regimen, even in patients of advanced age and above average BMI as well as in wounds that did not achieve > 40% wound surface area reduction at 4 weeks.

  4. In vitro percutaneous penetration and characterization of silver from silver-containing textiles

    Directory of Open Access Journals (Sweden)

    Bianco C

    2015-03-01

    Full Text Available Carlotta Bianco,1 Sanja Kezic,2 Matteo Crosera,1 Vesna Svetličić,3 Suzana Šegota,3 Giovanni Maina,4 Canzio Romano,5 Francesca Larese,6,7 Gianpiero Adami11Department of Chemical and Pharmaceutical Sciences, University of Trieste, Trieste, Italy; 2Academic Medical Center, Coronel Institute, University of Amsterdam, Amsterdam, the Netherlands; 3Laboratory for Bioelectrochemistry and Surface Imaging, Division for Marine and Environmental Research, Ruder Boškovic Institute, Zagreb, Croatia; 4Department of Clinical and Biological Sciences, University of Turin, Turin, Italy; 5Department of Public and Pediatric Health Sciences, University of Turin, Turin, Italy; 6Unit of Occupational Medicine, University of Trieste, Trieste, Italy; 7Department of Medical Sciences, University of Trieste, Trieste, ItalyAbstract: The objective of this study was to determine the in vitro percutaneous penetration of silver and characterize the silver species released from textiles in different layers of full thickness human skin. For this purpose, two different wound dressings and a garment soaked in artificial sweat were placed in the donor compartments of Franz cells for 24 hours. The concentration of silver in the donor phase and in the skin was determined by an electrothermal atomic absorption spectrometer (ET-AAS and by inductively coupled plasma mass spectrometer (ICP-MS. The characterization of silver species in the textiles and in the skin layers was made by scanning electron microscopy with integrated energy dispersive X-ray spectroscopy (SEM-EDX. Additionally, the size distribution of silver nanoparticles in the textiles was performed by atomic force microscopy (AFM. On the surface of all investigated materials, silver nanoparticles of different size and morphology were found. Released silver concentrations in the soaking solutions (ie, exposure concentration ranged from 0.7 to 4.7 µg/mL (0.6–4.0 µg/cm2, fitting the bactericidal range. Silver and silver

  5. Determination of fluoxetine in pharmaceutical and biological samples based on the silver nanoparticle enhanced fluorescence of fluoxetine-terbium complex.

    Science.gov (United States)

    Lotfi, Ali; Manzoori, Jamshid L

    2016-11-01

    In this study, a simple and sensitive spectrofluorimetric method is presented for the determination of fluoxetine based on the enhancing effect of silver nanoparticles (AgNPs) on the terbium-fluoxetine fluorescence emission. The AgNPs were prepared by a simple reduction method and characterized by UV-Vis spectroscopy and transmission electron microscopy. It was indicated that these AgNPs have a remarkable amplifying effect on the terbium-sensitized fluorescence of fluoxetine. The effects of various parameters such as AgNP and Tb 3+ concentration and the pH of the media were investigated. Under obtained optimal conditions, the fluorescence intensity of the terbium-fluoxetine-AgNP system was enhanced linearly by increasing the concentration of fluoxetine in the range of 0.008 to 19 mg/L. The limit of detection (b + 3s) was 8.3 × 10 -4 mg/L. The interference effects of common species found in real samples were also studied. The method had good linearity, recovery, reproducibility and sensitivity, and was satisfactorily applied for the determination of fluoxetine in tablet formulations, human urine and plasma samples. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Plasmonic photocatalysts based on silver nanoparticles - layered double hydroxides for efficient removal of toxic compounds using solar light

    Science.gov (United States)

    Gilea, Diana; Radu, Teodora; Muresanu, Mihaela; Carja, Gabriela

    2018-06-01

    Plasmon-enhanced photocatalysis holds important promise for chemical processes and outcomes. We present here the self-assemblies of silver nanoparticles (AgNP)/layered double hydroxides (LDHs: MeAlLDHs with Me2+ = Zn2+;Mg2+) and their derived AgNP/MMOs (type AgNP/MgAl2O4; AgNP/ZnO/ZnAl2O4) as novel plasmonic photocatalysts exhibiting activity for phenol photodegradation from aqueous solution by solar-light. The fabrication procedure of AgNP/LDHs assemblies is simple and cost effective and is based on the in-situ synthesis of AgNP on the LDHs matrices during the reconstruction of MgAlLDH and ZnAlLDH in the aqueous solution of Ag2SO4. The tested catalysts were thoroughly investigated - techniques to obtain information on their crystalline structure (XRD), surface properties (XPS), morphological features (TEM) and optical properties (UV-vis). The results show that the solar photocatalytic response of the catalysts is ascribed to the plasmonic response of AgNP though the catalytic efficiency is strongly influenced by the composition of the MeAlLDHs. The best photocatalytic performance was obtained on AgNP/ZnAlLDH750 catalyst that degraded 100% of phenol after 80 min of irradiation with solar light. The results reveal the high potential to tailor AgNP/LDHs and AgNP/MMOs as efficient photo-functional plasmonic hybrids for waste-water cleaning.

  7. Fast and sensitive metronidazole determination by means of voltammetry on renewable amalgam silver based electrode without the preconcentration step

    Directory of Open Access Journals (Sweden)

    Piech Robert

    2017-01-01

    Full Text Available Application of cyclic renewable amalgam silver-based electrode (Hg(AgFE for sensitive metronidazole detection by the differential pulse voltammetry (DPV is described. The unique properties of the Hg(AgFE such as the relative large surface area and its fast and very simple renewal were fully utilized for sensitive measurements. Compared with the classical hanging mercury drop electrode (HMDE, the renewable Hg(AgFE significantly increases the reduction peak current of metronidazole because of its large surface area. The effects of various factors for the metronidazole determination such as: pulse height and width, step potential, surface area of the working electrode, and basic electrolyte composition are optimized. The obtained calibration graph is linear from 0.1 (17 μg L-1 to 2 μM (342 μg L-1 with correlation coefficient 0.999. For the Hg(AgFE with the surface area of 10.1 mm2 the limit of detection (LOD is 20 nM (3.4 μg L-1. The repeatability of the method at a concentration of the analyte of 0.5 μM (5.6 μg L−1, expressed as relative standard deviation (RSD is 2.1 % (n = 7. The proposed method was successfully applied and confirmed by studying recovery of metronidazole from spiked samples.

  8. Non-enzymatic amperometric sensor for hydrogen peroxide based on a biocomposite made from chitosan, hemoglobin, and silver nanoparticles

    International Nuclear Information System (INIS)

    Tian, L.; Feng, Y.; Qi, Y.; Wang, B.; Chen, Y.; Fu, X.

    2012-01-01

    We report on a novel non-enzymatic sensor for hydrogen peroxide (HP) that is based on a biocomposite made up from chitosan (CS), hemoglobin (Hb), and silver nanoparticles (AgNPs). The AgNPs were prepared in the presence of CS and glucose in an ultrasonic bath, and CS is found to act as a stabilizing agent. They were then combined with Hb and CS to construct a carbon paste biosensor. The resulting electrode gave a well-defined redox couple for Hb, with a formal potential of about -0.17 V (vs. SCE) at pH 6. 86 and exhibited a remarkable electrocatalytic activity for the reduction of HP. The sensor was used to detect HP by flow injection analysis, and a linear response is obtained in the 0. 08 to 250 μM concentration range. The detection limit is 0.05 μM (at S/N = 3). These characteristics, along with its long-term stability make the sensor highly promising for the amperometric determination of HP. (author)

  9. Fabrication of flexible silver nanowire conductive films and transmittance improvement based on moth-eye nanostructure array

    Science.gov (United States)

    Zhang, Chengpeng; Zhu, Yuwen; Yi, Peiyun; Peng, Linfa; Lai, Xinmin

    2017-07-01

    Transparent conductive electrodes (TCEs) are widely used in optoelectronic devices, such as touch screens, liquid-crystal displays and light-emitting diodes. To date, the material of the most commonly used TCEs was indium-tin oxide (ITO), which had several intrinsic drawbacks that limited its applications in the long term, including relatively high material cost and brittleness. Silver nanowire (AgNW), as one of the alternative materials for ITO TCEs, has already gained much attention all over the world. In this paper, we reported a facile method to greatly enhance the transmittance of the AgNW TCEs without reducing the electrical conductivity based on moth-eye nanostructures, and the moth-eye nanostructures were fabricated by using a roll-to-roll ultraviolet nanoimprint lithography process. Besides, the effects of mechanical pressure and bending on the moth-eye nanostructure layer were also investigated. In the research, the optical transmittance of the flexible AgNW TCEs was enhanced from 81.3% to 86.0% by attaching moth-eye nanostructures onto the other side of the flexible polyethylene terephthalate substrate while the electrical conductivity of the AgNW TCEs was not sacrificed. This research can provide a direction for the cost-effective fabrication of moth-eye nanostructures and the transmittance improvement of the flexible transparent electrodes.

  10. Fabrication of flexible silver nanowire conductive films and transmittance improvement based on moth-eye nanostructure array

    International Nuclear Information System (INIS)

    Zhang, Chengpeng; Zhu, Yuwen; Yi, Peiyun; Peng, Linfa; Lai, Xinmin

    2017-01-01

    Transparent conductive electrodes (TCEs) are widely used in optoelectronic devices, such as touch screens, liquid-crystal displays and light-emitting diodes. To date, the material of the most commonly used TCEs was indium-tin oxide (ITO), which had several intrinsic drawbacks that limited its applications in the long term, including relatively high material cost and brittleness. Silver nanowire (AgNW), as one of the alternative materials for ITO TCEs, has already gained much attention all over the world. In this paper, we reported a facile method to greatly enhance the transmittance of the AgNW TCEs without reducing the electrical conductivity based on moth-eye nanostructures, and the moth-eye nanostructures were fabricated by using a roll-to-roll ultraviolet nanoimprint lithography process. Besides, the effects of mechanical pressure and bending on the moth-eye nanostructure layer were also investigated. In the research, the optical transmittance of the flexible AgNW TCEs was enhanced from 81.3% to 86.0% by attaching moth-eye nanostructures onto the other side of the flexible polyethylene terephthalate substrate while the electrical conductivity of the AgNW TCEs was not sacrificed. This research can provide a direction for the cost-effective fabrication of moth-eye nanostructures and the transmittance improvement of the flexible transparent electrodes. (paper)

  11. Vegetable-Oil-Based Hyperbranched Polyester-Styrene Copolymer Containing Silver Nanoparticle as Antimicrobial and Corrosion-Resistant Coating Materials

    Directory of Open Access Journals (Sweden)

    Manawwer Alam

    2013-01-01

    Full Text Available Pongamia oil (PO was converted to Pongamia oil hydroxyl (POH via epoxidation process. The esterification of POH with linolenic acid was carried out to form hyperbranched polyester (HBPE, and further styrenation was performed at the conjugated double bond in the chain of linolenic acid. After styrenation, silver nanoparticle was added in different weight percentages (0.1–0.4 wt%. The structural elucidation of POH, HBPE, and HBPE-St was carried out by FT-IR, 1H-NMR, and 13C-NMR spectroscopic techniques. Physicochemical and physicomechanical analyses were performed by standard method. Thermal behavior of the HBPE-St was analyzed by using thermogravimetric analysis (TGA and differential scanning calorimetry (DSC. The coatings of HBPE-St were prepared on mild steel strips. The anticorrosive behavior of HBPE-St resin-based coatings in acid, saline, and tap water was evaluated, and the molecular weight of HBPE-St was determined by gel permeation chromatography (GPC. The antibacterial activities of the HBPE-St copolymers were tested in vitro against bacteria and fungi by disc diffusion method. The HBPE-St copolymers exhibited good antibacterial activities and can be used as antimicrobial and corrosion-resistant coating materials.

  12. Preconcentration of silver as silver xanthate on activated carbon

    International Nuclear Information System (INIS)

    Ramadevi, P.; Naidu, U.V.; Naidu, G.R.K.

    1988-01-01

    Silver from aqueous solution was preconcentrated by adsorption on activated carbon as silver xanthate. Factors influencing the adsorption of silver were studied. Optimum conditions for the preconcentration of silver were established. (author) 9 refs.; 3 tabs

  13. Wound Healing Bionanocomposites Based on Castor Oil Polymeric Films Reinforced with Chitosan-Modified ZnO Nanoparticles.

    Science.gov (United States)

    Díez-Pascual, Ana M; Díez-Vicente, Angel L

    2015-09-14

    Castor oil (CO), which is a readily available, relatively inexpensive, and environmentally benign nonedible oil, has been successfully used as matrix material to prepare biocompatible and biodegradable nanocomposite films filled with chitosan (CS)-modified ZnO nanoparticles. The biocomposites were synthesized via a simple and versatile solution mixing and casting method. The morphology, structure, thermal stability, water absorption, biodegradability, cytocompatibility, barrier, mechanical, viscoelastic, antibacterial, and wound healing properties of the films have been analyzed. FT-IR spectra were used to obtain information about the nanoparticle-matrix interactions. The thermal stability, hydrophilicity, degree of porosity, water absorption, water vapor transmission rate (WVTR), oxygen permeability (Dk), and biodegradability of the films increased with the CS-ZnO loading. The WVTR and Dk data obtained are within the range of values reported for commercial wound dressings. Tensile tests demonstrated that the nanocomposites displayed a good balance between elasticity, strength, and flexibility under both dry and simulated body fluid (SBF) environments. The flexibility increased in a moist atmosphere due to the plasticization effect of absorbed water. The nanocomposites also exhibited significantly enhanced dynamic mechanical performance (storage modulus and glass transition temperature) than neat CO under different humidity conditions. The antibacterial activity of the films against Escherichia coli, Staphylococcus aureus, and Micrococcus luteus bacteria was investigated in the presence and the absence of UV light. The biocide effect increased progressively with the CS-ZnO content and was systematically stronger against Gram-positive cells. Composites with nanoparticle loading ≤5.0 wt % exhibited very good in vitro cytocompatibility and enabled a faster wound healing than neat CO and control gauze, hence showing great potential to be applied as antibacterial

  14. Preparation of Polyvinyl Pyrrolidone-Based Hydrogels by Radiation Induced Crosslinking with Potential Application as Wound Dressing

    International Nuclear Information System (INIS)

    Abd EI-Mohdy, H.L.; Hegazy, E.A.

    2009-01-01

    Polyvinyl pyrrolidone l polyethylene glycol hydrogels (PVP/ PEG) and PVP/ PEG/ Starch were prepared by irradiating the mixtures of aqueous solutions of PVP, PEG and starch with electron beam at different doses. Its properties were evaluated to identify their usability in wound dressing applications. Hydrogel dressing can protect injured skin and keep it appropriately moist to speed the healing process. The physical properties of the prepared hydrogels, such as gel content, swelling, water content and degree of water evaporation with varying composition and irradiation dose were examined to evaluate the usefulness of the hydrogels for wound dressing. The gel content increases with increasing PVP concentration due to increased crosslink density, and decreases with increasing the PEG concentration. PEG seems to act not only as plasticizer but also to modify the gel properties as gelation% and maximum swelling. Mechanical experiments were conducted for both of PVP/PEG and PVP/PEG/ Starch. The adding of PEG and starch to PVP significantly improve elongation and tensile strength of prepared hydrogels. The crystallinity of prepared hydrogels was investigated with varying their components. XRD studies indicated that the crystallinity in the gel was mainly due to PVP and decreased with enhanced starch content. The prepared hydrogels had sufficient strength to be used as wound dressing and could be considered as a good barrier against microbes

  15. Amperometric sensor for ascorbic acid based on a glassy carbon electrode modified with gold-silver bimetallic nanotubes in a chitosan matrix

    International Nuclear Information System (INIS)

    Yang, Penghao; Gao, Xia; Wang, Lisha; Wu, Qi; Chen, Zhichun; Lin, Xianfu

    2014-01-01

    We report on an amperometric sensor for ascorbic acid (AA) that is based on highly dense gold-silver nanotubes in a chitosan film on a glassy carbon electrode. The nanotubes were synthesized by a poly(vinyl pyrrolidone)-mediated polyol method employing a replacement reaction with silver nanowires as templates, and were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Under the optimal conditions, the sensor exhibits good electrocatalytic activity towards the oxidation of AA, and this enables the determination of AA in the 5 μM to 2 mM concentration range, with a detection limit at 2 μM (at an S/N of 3). The response time is 2 s. The sensor displays good reproducibility, selectivity, sensitivity, and long-term stability. (author)

  16. Role of Silver Salts Lattice Energy on Conductivity Drops in Chitosan Based Solid Electrolyte: Structural, Morphological and Electrical Characteristics

    Science.gov (United States)

    Aziz, Shujahadeen B.; Abdullah, Omed Gh.; Hussein, Sarkawt A.

    2018-03-01

    The influence of anion type on silver ion reduction and drop in direct current (DC) conductivity was investigated experimentally. The structural, optical, morphological and electrical properties of the samples were investigated using x-ray diffraction (XRD), ultraviolet-visible (UV-Vis), optical micrographs (OM) and impedance spectroscopy. The XRD results reveal significant disruption in the crystalline structure of chitosan (CS) for different concentrations of silver nitrate (AgNt) salt. The localized surface resonance plasmonic (LSRP) peaks that were observed for CS:AgNt samples, along with the white silver specs detected by OM technique confirm the formation of Ag nanoparticles. The appearance of obvious dark regions in the CS:AgNt system reveals the existence of a large percentage of amorphous domains. The nonexistence of spherulitic texture confirms the amorphous nature of the samples. The second semicircle in an impedance plot can be attributed to an Ag nanoparticle grain boundary. The established relationships between dielectric constant and carrier concentration and the behavior of dielectric constant versus salt concentration were used to explain the phenomenon of ion-ion association. The continuous increase of DC conductivity was noticed at high temperatures, which was then explained on the basis of lattice energy of silver salts. The influences of anion size on the rate of silver ion reductions are also interpreted.

  17. Highly sensitive, reproducible and stable SERS substrate based on reduced graphene oxide/silver nanoparticles coated weighing paper

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Guina, E-mail: xiaoguina@shnu.edu.cn; Li, Yunxiang; Shi, Wangzhou; Shen, Leo; Chen, Qi; Huang, Lei, E-mail: leihuang@shnu.edu.cn

    2017-05-15

    Highlights: • We developed a paper-based SERS substrate by gravure and inkjet printing methods. • The S-RGO/AgNPs comoposite structure had higher SERS activity than the pure AgNPs. • The Raman enhancement factor of S-RGO/AgNPs substrate was calculated to be 10{sup 9}. • The paper-based substrate exhibited good reproducibility and long-term stability. - Abstract: Paper-based surface-enhanced Raman scattering (SERS) substrates receive a great deal of attention due to low cost and high flexibility. Herein, we developed an efficient SERS substrate by gravure printing of sulfonated reduced graphene-oxide (S-RGO) thin film and inkjet printing of silver nanoparticles (AgNPs) on weighing paper successively. Malachite green (MG) and rhodamine 6G (R6G) were chosen as probe molecules to evaluate the enhanced performance of the fabricated SERS-active substrates. It was found that the S-RGO/AgNPs composite structure possessed higher enhancement ability than the pure AgNPs. The Raman enhancement factor of S-RGO/AgNPs was calculated to be as large as 10{sup 9}. The minimum detection limit for MG and R6G was down to 10{sup −7} M with good linear responses (R{sup 2} = 0.9996, 0.9983) range from 10{sup −4} M to 10{sup −7} M. In addition, the S-RGO/AgNPs exhibited good uniformity with a relative standard deviation (RSD) of 7.90% measured by 572 points, excellent reproducibility with RSD smaller than 3.36%, and long-term stability with RSD less than 7.19%.

  18. Localization of mineralization, its age, and relationship to magmatism at the Mogot silver-base-metal deposit, North Stanovoi metallogenic zone in the southeastern framework of the North Asian Craton

    Science.gov (United States)

    Buchko, I. V.; Buchko, Ir. V.; Sorokin, A. A.; Ponomarchuk, V. A.; Travin, A. V.

    2014-03-01

    The results of studying the Mogot silver-base-metal deposit located in the Dzhugdzhur-Stanovoi Superterrane are discussed in this paper. The main ore-controlling structural elements of the studied district are near-latitudinal and NE-trending faults, which are accompanied by zones of hydrothermal metasomatic potassic, propylitic, and argillic alterations, breccias with quartz and quartz-carbonate cement replacing metamorphic rocks and granitoids of the Late Stanovoi Complex. The total sulfide content in ore is 2-3%. The high Ag, Pb, and Zn contents in ore allow us to consider the Mogot deposit as silver-base-metal, since except of orebody 4, there are no silver minerals proper. This indicates that silver is incorporated into crystalline lattice of sulfides. The results of 40Ar/39Ar geochronological investigations show that the hydrothermal ore deposition dated at 127-125 Ma was related to emplacement of intrusions pertaining to the Tynda-Bakaran Complex.

  19. Nanomedicine and advanced technologies for burns: Preventing infection and facilitating wound healing.

    Science.gov (United States)

    Mofazzal Jahromi, Mirza Ali; Sahandi Zangabad, Parham; Moosavi Basri, Seyed Masoud; Sahandi Zangabad, Keyvan; Ghamarypour, Ameneh; Aref, Amir R; Karimi, Mahdi; Hamblin, Michael R

    2018-01-01

    According to the latest report from the World Health Organization, an estimated 265,000 deaths still occur every year as a direct result of burn injuries. A widespread range of these deaths induced by burn wound happens in low- and middle-income countries, where survivors face a lifetime of morbidity. Most of the deaths occur due to infections when a high percentage of the external regions of the body area is affected. Microbial nutrient availability, skin barrier disruption, and vascular supply destruction in burn injuries as well as systemic immunosuppression are important parameters that cause burns to be susceptible to infections. Topical antimicrobials and dressings are generally employed to inhibit burn infections followed by a burn wound therapy, because systemic antibiotics have problems in reaching the infected site, coupled with increasing microbial drug resistance. Nanotechnology has provided a range of molecular designed nanostructures (NS) that can be used in both therapeutic and diagnostic applications in burns. These NSs can be divided into organic and non-organic (such as polymeric nanoparticles (NPs) and silver NPs, respectively), and many have been designed to display multifunctional activity. The present review covers the physiology of skin, burn classification, burn wound pathogenesis, animal models of burn wound infection, and various topical therapeutic approaches designed to combat infection and stimulate healing. These include biological based approaches (e.g. immune-based antimicrobial molecules, therapeutic microorganisms, antimicrobial agents, etc.), antimicrobial photo- and ultrasound-therapy, as well as nanotechnology-based wound healing approaches as a revolutionizing area. Thus, we focus on organic and non-organic NSs designed to deliver growth factors to burned skin, and scaffolds, dressings, etc. for exogenous stem cells to aid skin regeneration. Eventually, recent breakthroughs and technologies with substantial potentials in tissue

  20. Pyrrolo-dC Metal-Mediated Base Pairs in the Reverse Watson-Crick Double Helix: Enhanced Stability of Parallel DNA and Impact of 6-Pyridinyl Residues on Fluorescence and Silver-Ion Binding.

    Science.gov (United States)

    Yang, Haozhe; Mei, Hui; Seela, Frank

    2015-07-06

    Reverse Watson-Crick DNA with parallel-strand orientation (ps DNA) has been constructed. Pyrrolo-dC (PyrdC) nucleosides with phenyl and pyridinyl residues linked to the 6 position of the pyrrolo[2,3-d]pyrimidine base have been incorporated in 12- and 25-mer oligonucleotide duplexes and utilized as silver-ion binding sites. Thermal-stability studies on the parallel DNA strands demonstrated extremely strong silver-ion binding and strongly enhanced duplex stability. Stoichiometric UV and fluorescence titration experiments verified that a single (2py) PyrdC-(2py) PyrdC pair captures two silver ions in ps DNA. A structure for the PyrdC silver-ion base pair that aligns 7-deazapurine bases head-to-tail instead of head-to-head, as suggested for canonical DNA, is proposed. The silver DNA double helix represents the first example of a ps DNA structure built up of bidentate and tridentate reverse Watson-Crick base pairs stabilized by a dinuclear silver-mediated PyrdC pair. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. [Errors in wound management].

    Science.gov (United States)

    Filipović, Marinko; Novinscak, Tomislav

    2014-10-01

    Chronic ulcers have adverse effects on the patient quality of life and productivity, thus posing financial burden upon the healthcare system. Chronic wound healing is a complex process resulting from the interaction of the patient general health status, wound related factors, medical personnel skill and competence, and therapy related products. In clinical practice, considerable improvement has been made in the treatment of chronic wounds, which is evident in the reduced rate of the severe forms of chronic wounds in outpatient clinics. However, in spite of all the modern approaches, efforts invested by medical personnel and agents available for wound care, numerous problems are still encountered in daily practice. Most frequently, the problems arise from inappropriate education, of young personnel in particular, absence of multidisciplinary approach, and inadequate communication among the personnel directly involved in wound treatment. To perceive them more clearly, the potential problems or complications in the management of chronic wounds can be classified into the following groups: problems mostly related to the use of wound coverage and other etiology related specificities of wound treatment; problems related to incompatibility of the agents used in wound treatment; and problems arising from failure to ensure aseptic and antiseptic performance conditions.

  2. Selective liquid-phase oxidation of alcohols catalyzed by a silver-based catalyst promoted by the presence of ceria

    DEFF Research Database (Denmark)

    Beier, Matthias Josef; Hansen, Thomas Willum; Grunwaldt, Jan-Dierk

    2009-01-01

    simultaneously. When a high catalytic conversion (>30% over 2 h) was found the number of catalyst components was reduced in the following tests. Thereby, a collaborative effect between a physical mixture of ceria nanoparticles and silver-impregnated silica (10 wt.% Ag–SiO2) was found. The catalytic activity...... by in situ XAS experiments. Oxygen species incorporated in the silver lattice appear to be important for the catalytic oxidation of the alcohol for which a preliminary mechanism is presented. The application of the catalyst was extended to the oxidation of a wide range of primary and secondary alcohols....... Compared to palladium and gold catalysts, the new silver catalyst performed similarly or even superior in the presence of CeO2. In addition, the presence of ceria increased the catalytic activity of all investigated catalysts....

  3. Wound Healing Effects of Prunus yedoensis Matsumura Bark in Scalded Rats

    Directory of Open Access Journals (Sweden)

    Jin-Ho Lee

    2017-01-01

    Full Text Available Pruni Cortex has been used to treat asthma, measles, cough, urticaria, pruritus, and dermatitis in traditional Korean medicine. The objective of this study was to investigate the effects of Prunus yedoensis Matsumura bark methanol extract (PYE on scald-induced dorsal skin wounds in rats. Scalds were produced in Sprague-Dawley rats with 100°C water and treated with 5% and 20% PYE (using Vaseline as a base, silver sulfadiazine (SSD, and Vaseline once a day for 21 days, beginning 24 hours after scald by treatment group allocation. The PYE-treated groups showed accelerated healing from 12 days after scald, demonstrated by rapid eschar exfoliation compared to the control and SSD groups. PYE-treated groups showed higher wound contraction rates and better tissue regeneration in comparison with the control group. Serum analysis showed that transforming growth factor beta 1 and vascular endothelial growth factor levels remained high or gradually increased up to day 14 in both PYE groups and then showed a sharp decline by day 21, implying successful completion of the inflammatory phase and initiation of tissue regeneration. These findings suggested that PYE is effective in promoting scald wound healing in the inflammation and tissue proliferation stages.

  4. The effect of using nano-silver dispersed water based nanofluid as a passive method for energy efficiency enhancement in a plate heat exchanger

    International Nuclear Information System (INIS)

    Behrangzade, Ali; Heyhat, Mohammad Mahdi

    2016-01-01

    Highlights: • The effect of using nano-silver on a commercial plate heat exchanger was studied. • An experimental rig was designed to investigate the thermo-hydrodynamic features of nanofluid. • The overall heat transfer coefficient becomes larger 16.79% for 100 ppm nanofluid. • No significant growth in pressure drop values was observed. • The process temperatures have important role in nanofluid influence. - Abstract: The purpose of this study is to verify the potential using of nano-silver dispersed water based nanofluid on efficiency improvement of a commercial corrugated plate heat exchanger. In this regards, an experimental rig was provided to recognize the heat transfer rate and pressure drop of Ag–water nanofluid as the working fluid. The two most key thermo-physical properties, i.e. dynamic viscosity and thermal conductivity of nanofluids were experimentally gauged. The findings, which were achieved, displayed that the overall heat transfer coefficient becomes larger, from 6.18% to 16.79%, for 100 ppm silver nanofluid. While using nanofluid, no significant growth in pressure drop values was observed. Moreover, the process temperatures and flow rates have significant impacts on the helpfulness of applying nanofluid in a plate heat exchanger.

  5. Biofilms in wounds

    DEFF Research Database (Denmark)

    Cooper, R A; Bjarnsholt, Thomas; Alhede, M

    2014-01-01

    Following confirmation of the presence of biofilms in chronic wounds, the term biofilm became a buzzword within the wound healing community. For more than a century pathogens have been successfully isolated and identified from wound specimens using techniques that were devised in the nineteenth...... extracellular polymeric substances (EPS). Cells within such aggregations (or biofilms) display varying physiological and metabolic properties that are distinct from those of planktonic cells, and which contribute to their persistence. There are many factors that influence healing in wounds and the discovery...... of biofilms in chronic wounds has provided new insight into the reasons why. Increased tolerance of biofilms to antimicrobial agents explains the limited efficacy of antimicrobial agents in chronic wounds and illustrates the need to develop new management strategies. This review aims to explain the nature...

  6. Factors Affecting Wound Healing

    Science.gov (United States)

    Guo, S.; DiPietro, L.A.

    2010-01-01

    Wound healing, as a normal biological process in the human body, is achieved through four precisely and highly programmed phases: hemostasis, inflammation, proliferation, and remodeling. For a wound to heal successfully, all four phases must occur in the proper sequence and time frame. Many factors can interfere with one or more phases of this process, thus causing improper or impaired wound healing. This article reviews the recent literature on the most significant factors that affect cutaneous wound healing and the potential cellular and/or molecular mechanisms involved. The factors discussed include oxygenation, infection, age and sex hormones, stress, diabetes, obesity, medications, alcoholism, smoking, and nutrition. A better understanding of the influence of these factors on repair may lead to therapeutics that improve wound healing and resolve impaired wounds. PMID:20139336

  7. Chitosan-based films composites for wound healing purposes; Filmes compositos de quitosana para aplicacao no revestimento de ferimentos

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Natali de O.; Silva, Gabriela T. da; Schulz, Gracelie A.S.; Fajardo, Andre R., E-mail: natalioliveiraalves@gmail.com [Universidade Federal de Pelotas (LaCoPol/UFPel), Pelotas, RS (Brazil). Centro de Ciencias Quimicas, Farmaceuticas e de Alimentos. Lab. de Tecnologia e Desenvolvimento de Compositos e Materiais Polimericos

    2015-07-01

    Chitosan has been extensively applied in the developing of biomaterials due to its desirable good physico-chemical and biological properties. According to this, here films composite of chitosan, poly(vinyl alcohol) and bovine bone powder were prepared by casting willing to be applied in wound healing purposes. Moreover, the first step was the developing of a suitable method to obtain bovine bone powder, which was utilized here as filler. All the materials and films were fully characterized by FTIR, DRX and thermal analysis. Water uptake capacity was measured by swelling assays. (author)

  8. Factors Affecting Wound Healing

    OpenAIRE

    Guo, S.; DiPietro, L.A.

    2010-01-01

    Wound healing, as a normal biological process in the human body, is achieved through four precisely and highly programmed phases: hemostasis, inflammation, proliferation, and remodeling. For a wound to heal successfully, all four phases must occur in the proper sequence and time frame. Many factors can interfere with one or more phases of this process, thus causing improper or impaired wound healing. This article reviews the recent literature on the most significant factors that affect cutane...

  9. Plasmonic 3D-structures based on silver decorated nanotips for biological sensing

    KAUST Repository

    Coluccio, M. L.; Francardi, Marco; Gentile, F.; Candeloro, P.; Ferrara, L.; Perozziello, G.; Di Fabrizio, Enzo M.

    2015-01-01

    Recent progresses in nanotechnology fabrication gives the opportunity to build highly functional nano-devices. 3D structures based on noble metals or covered by them can be realized down to the nano-scales, obtaining different devices

  10. A supersensitive silver nanoprobe based aptasensor for low cost detection of malathion residues in water and food samples

    Science.gov (United States)

    Bala, Rajni; Mittal, Sherry; Sharma, Rohit K.; Wangoo, Nishima

    2018-05-01

    In the present study, we report a highly sensitive, rapid and low cost colorimetric monitoring of malathion (an organophosphate insecticide) employing a basic hexapeptide, malathion specific aptamer (oligonucleotide) and silver nanoparticles (AgNPs) as a nanoprobe. AgNPs are made to interact with the aptamer and peptide to give different optical responses depending upon the presence or absence of malathion. The nanoparticles remain yellow in color in the absence of malathion owing to the binding of aptamer with peptide which otherwise tends to aggregate the particles because of charge based interactions. In the presence of malathion, the agglomeration of the particles occurs which turns the solution orange. Furthermore, the developed aptasensor was successfully applied to detect malathion in various water samples and apple. The detection offered high recoveries in the range of 89-120% with the relative standard deviation within 2.98-4.78%. The proposed methodology exhibited excellent selectivity and a very low limit of detection i.e. 0.5 pM was achieved. The developed facile, rapid and low cost silver nanoprobe based on aptamer and peptide proved to be potentially applicable for highly selective and sensitive colorimetric sensing of trace levels of malathion in complex environmental samples. Figure S2. HPLC Chromatogram of KKKRRR. Figure S3. UV- Visible spectra of AgNPs in the presence of increasing peptide concentrations. Inset shows respective color changes of AgNPs with peptide concentrations ranging from 0.1 mM to 100 mM (a to e). Figure S4. UV- Visible spectra of AgNPs in the presence 10 mM peptide and varying aptamer concentrations. Inset shows the corresponding color changes. a to e shows aptamer concentrations ranging from 10 nM to 1000 nM. Figure S5. Interference Studies. Ratio of A520 nm/390 nm of AgNPs in the presence of 10 mM peptide, 500 nM aptamer, 0.5 nM malathion and 0.5 mM interfering components i.e. sodium, potassium, calcium, alanine, arginine

  11. High-Resolution Crystal Structure of a Silver(I)-RNA Hybrid Duplex Containing Watson-Crick-like C-Silver(I)-C Metallo-Base Pairs.

    Science.gov (United States)

    Kondo, Jiro; Tada, Yoshinari; Dairaku, Takenori; Saneyoshi, Hisao; Okamoto, Itaru; Tanaka, Yoshiyuki; Ono, Akira

    2015-11-02

    Metallo-base pairs have been extensively studied for applications in nucleic acid-based nanodevices and genetic code expansion. Metallo-base pairs composed of natural nucleobases are attractive because nanodevices containing natural metallo-base pairs can be easily prepared from commercially available sources. Previously, we have reported a crystal structure of a DNA duplex containing T-Hg(II)-T base pairs. Herein, we have determined a high-resolution crystal structure of the second natural metallo-base pair between pyrimidine bases C-Ag(I)-C formed in an RNA duplex. One Ag(I) occupies the center between two cytosines and forms a C-Ag(I)-C base pair through N3-Ag(I)-N3 linear coordination. The C-Ag(I)-C base pair formation does not disturb the standard A-form conformation of RNA. Since the C-Ag(I)-C base pair is structurally similar to the canonical Watson-Crick base pairs, it can be a useful building block for structure-based design and fabrication of nucleic acid-based nanodevices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Telemedicine for wound management

    Directory of Open Access Journals (Sweden)

    Ravi K Chittoria

    2012-01-01

    Full Text Available The escalating physiological, psychological, social and financial burdens of wounds and wound care on patients, families and society demand the immediate attention of the health care sector. Many forces are affecting the changes in health care provision for patients with chronic wounds, including managed care, the limited number of wound care therapists, an increasingly ageing and disabled population, regulatory and malpractice issues, and compromised care. The physician is also faced with a number of difficult issues when caring for chronic wound patients because their conditions are time consuming and high risk, represent an unprofitable part of care practice and raise issues of liability. Telemedicine enhances communication with the surgical wound care specialist. Digital image for skin lesions is a safe, accurate and cost-effective referral pathway. The two basic modes of telemedicine applications, store and forward (asynchronous transfer and real-time transmission (synchronous transfer, e.g. video conference, are utilized in the wound care setting. Telemedicine technology in the hands of an experienced physician can streamline management of a problem wound. Although there is always an element of anxiety related to technical change, the evolution of wound care telemedicine technology has demonstrated a predictable maturation process.

  13. Saliva and wound healing.

    Science.gov (United States)

    Brand, Henk S; Ligtenberg, Antoon J M; Veerman, Enno C I

    2014-01-01

    Oral wounds heal faster and with less scar formation than skin wounds. One of the key factors involved is saliva, which promotes wound healing in several ways. Saliva creates a humid environment, thus improving the survival and functioning of inflammatory cells that are crucial for wound healing. In addition, saliva contains several proteins which play a role in the different stages of wound healing. Saliva contains substantial amounts of tissue factor, which dramatically accelerates blood clotting. Subsequently, epidermal growth factor in saliva promotes the proliferation of epithelial cells. Secretory leucocyte protease inhibitor inhibits the tissue-degrading activity of enzymes like elastase and trypsin. Absence of this protease inhibitor delays oral wound healing. Salivary histatins in vitro promote wound closure by enhancing cell spreading and cell migration, but do not stimulate cell proliferation. A synthetic cyclic variant of histatin exhibits a 1,000-fold higher activity than linear histatin, which makes this cyclic variant a promising agent for the development of a new wound healing medication. Conclusively, recognition of the many roles salivary proteins play in wound healing makes saliva a promising source for the development of new drugs involved in tissue regeneration.

  14. Searching for Natural Conductive Fibrous Structures via a Green Sustainable Approach Based on Jute Fibers and Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Diana P. Ferreira

    2018-01-01

    Full Text Available This paper provides new insights regarding jute fibers functionalization with silver nanoparticles (Ag NPs with improved conductivity values and highlights the sustainability of the processes involved. These NPs were applied onto jute fabrics by two different sustainable methods: ultraviolet (UV photoreduction and by using polyethylene glycol (PEG as a reducing agent and stabilizer. Field Emission Scanning Electron Microscopy (FESEM images demonstrated that the Ag NPs were incorporated on the jute fibers surface by the two different approaches, with sizes ranging from 70 to 100 nm. Diffuse reflectance spectra revealed the plasmon absorption band, corresponding to the formation of metallic Ag NPs, in all samples under study. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR was used to characterize the obtained samples, demonstrating NPs adsorption to the surface of the fibers. The resistivity value obtained by the two-point probe method of the jute fabric without functionalization is about 1.5 × 107 Ω·m, whereas, after NPs functionalization, it decreased almost 15,000 times, reaching a value of 1.0 × 103 Ω·m. Further research work is being undertaken for improving these values, however, 1000 Ω·m of resistivity (conductivity = 0.001 S/m is already a very reasonable value when compared with those obtained with other developed systems based on natural fibers. In summary, this work shows that the use of very simple methodologies enabled the functionalization of jute fibers with reasonable values of conductivity. This achievement has a huge potential for use in smart textile composites.

  15. Evaluation of optimal silver amount for the removal of methyl iodide on silver-impregnated adsorbents

    International Nuclear Information System (INIS)

    Park, G.I.; Cho, I.H.; Kim, J.H.; Oh, W.Z.

    2001-01-01

    The adsorption characteristics of methyl iodide generated from the simulated off-gas stream on various adsorbents such as silver-impregnated zeolite (AgX), zeocarbon and activated carbon were investigated. An extensive evaluation was made on the optimal silver impregnation amount for the removal of methyl iodide at temperatures up to 300 deg. C. The degree of adsorption efficiency of methyl iodide on silver-impregnated adsorbent is strongly dependent on impregnation amount and process temperature. A quantitative comparison of adsorption efficiencies on three adsorbents in a fixed bed was investigated. The influence of temperature, methyl iodide concentration and silver impregnation amount on the adsorption efficiency is closely related to the pore characteristics of adsorbents. It shows that the effective impregnation ratio was about 10wt%, based on the degree of silver utilization for the removal of methyl iodide. The practical applicability of silver-impregnated zeolite for the removal of radioiodine generated from the DUPIC process was consequently proposed. (author)

  16. Construction and Application of Flow Enzymatic Biosensor Based of Silver Solid Amalgam Electrode for Determination of Sarcosine

    Czech Academy of Sciences Publication Activity Database

    Josypčuk, Oksana; Barek, J.; Josypčuk, Bohdan

    2015-01-01

    Roč. 27, č. 11 (2015), s. 2559-2566 ISSN 1040-0397 R&D Projects: GA ČR GBP206/12/G151; GA ČR GAP206/11/1638 Institutional support: RVO:61388955 Keywords : biosensors * sarcosine * silver solid amalgam electrode Subject RIV: CG - Electrochemistry Impact factor: 2.471, year: 2015

  17. Optical anisotropy of layered metal-dielectric nanostructures based on dense 2D-arrays of silver nanoparticles

    International Nuclear Information System (INIS)

    Jeshchenko, O.A.

    2013-01-01

    The spatial and polarization anisotropy of extinction spectra of parallel dense 2D-monolayers of Ag nanoparticles separated by dielectric films is theoretically studied. The dependences are interpreted as a result of collectivization of surface plasmon modes occurring due to strong dipole-dipole coupling silver nanoparticles

  18. Polymer films with size-selected silver nanoparticles as plasmon resonance-based transducers for protein sensing

    DEFF Research Database (Denmark)

    Muhammad, Hanif; Juluri, Raghavendra Rao; Fojan, Peter

    2016-01-01

    and deposited on the films in vacuum. Immersion of NPs is controlled by post-deposition thermal annealing providing very good adhesion, in particular, resistance against following wet chemical procedures. LSPR properties of silver NPs are exploited for protein detection using a classical antibody-antigen scheme...

  19. Prevalence of lymphoedema and quality of life among patients attending a hospital-based wound management and vascular clinic.

    LENUS (Irish Health Repository)

    Gethin, Georgina

    2012-04-01

    Lymphoedema is a chronic, incurable, debilitating condition, usually affecting a limb and causes discomfort, pain, heaviness, limited motion, unsatisfactory appearance and impacts on quality of life. However, there is a paucity of prevalence data on this condition. This study aimed to determine the prevalence of lymphoedema among persons attending wound management and vascular clinics in an acute tertiary referral hospital. Four hundred and eighteen patients meeting the inclusion criteria were assessed. A prevalence rate of 2.63% (n = 11) was recorded. Thirty-six percent (n = 4) had history of cellulitis and broken skin, 64% (n = 7) had history of broken skin and 36% (n = 4) had undergone treatment for venous leg ulcers. The most common co-morbidities were hypertension 55% (n = 6), deep vein thrombosis (DVT) 27% (n = 3), hypercholesterolemia 36% (n = 4) and type 2 diabetes 27% (n = 3). Quality of life scores identified that physical functioning was the domain most affected among this group. This study has identified the need to raise awareness of this condition among clinicians working in the area of wound management.

  20. Designing tragacanth gum based sterile hydrogel by radiation method for use in drug delivery and wound dressing applications.

    Science.gov (United States)

    Singh, Baljit; Varshney, Lalit; Francis, Sanju; Rajneesh

    2016-07-01

    Present article discusses synthesis and characterization of the sterile and pure hydrogel wound dressings which were prepared through radiation method by using polyvinyl alcohol (PVA), tragacanth gum (TG) and sodium alginate (SA). The polymer films were characterized by SEM, Cryo-SEM, FTIR, solid state C(13) NMR and XRD, TGA, and DSC. Some important biological properties such as O2 permeability, water vapor transmission rate, microbial permeability, haemolysis, thrombogenic behavior, antioxidant activity, bio-adhesion and mechanical properties were also studied. The hydrogel film showed thrombogenicity (82.43±1.54%), haemolysis (0.83±0.09%), oxygen permeability (6.433±0.058mg/L) and water vapor permeability (197.39±25.34g/m(2)/day). Hydrogel films were found biocompatible and impermeable to microbes. The release of antibiotic drug moxifloxacin occurred through non-Fickian mechanism and release profile was best fitted in Hixson-Crowell model for drug release. Overall, these results indicate the suitability of these hydrogels in wound dressing applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. ITO-Free Semitransparent Organic Solar Cells Based on Silver Thin Film Electrodes

    Directory of Open Access Journals (Sweden)

    Zhizhe Wang

    2014-01-01

    Full Text Available ITO-free semitransparent organic solar cells (OSCs based on MoO3/Ag anodes with poly(3-hexylthiophene and [6,6]-phenyl-C61-butyric acid methyl ester films as the active layer are investigated in this work. To obtain the optimal transparent (MoO3/Ag anode, ITO-free reference OSCs are firstly fabricated. The power conversion efficiency (PCE of 2.71% is obtained for OSCs based on the optimal MoO3 (2 nm/Ag (9 nm anode, comparable to that of ITO-based reference OSCs (PCE of 2.85%. Then based on MoO3 (2 nm/Ag (9 nm anode, ITO-free semitransparent OSCs with different thickness combination of Ca and Ag as the cathodes are investigated. It is observed from our results that OSCs with Ca (15 nm/Ag (15 nm cathode have the optimal transparency. Meanwhile, the PCE of 1.79% and 0.67% is obtained for illumination from the anode and cathode side, respectively, comparable to that of similar ITO-based semitransparent OSCs (PCE of 1.59% and 0.75% for illumination from the anode and cathode side, resp. (Sol. Energy Mater. Sol. Cells, 95, pp. 877–880, 2011. The transparency and PCE of ITO-free semitransparent OSCs can be further improved by introducing a light couple layer. The developed method is compatible with various substrates, which is instructive for further research of ITO-free semitransparent OSCs.

  2. Preparation and Property Research of Strain Sensor Based on PDMS and Silver Nanomaterials

    Directory of Open Access Journals (Sweden)

    Lihua Liu

    2017-01-01

    Full Text Available Based on the advantages and broad applications of stretchable strain sensors, this study reports a simple method to fabricate a highly sensitive strain sensor with Ag nanomaterials-polydimethylsiloxane (AgNMs-PDMS to create a synergic conductive network and a sandwich-structure. Three Ag nanomaterial samples were synthesized by controlling the concentrations of the FeCl3 solution and reaction time via the heat polyols thermal method. The AgNMs network’s elastomer nanocomposite-based strain sensors show strong piezoresistivity with a high gauge factor of 547.8 and stretchability from 0.81% to 7.26%. The application of our high-performance strain sensors was demonstrated by the inducting finger of the motion detection. These highly sensitive sensors conform to the current trends of flexible electronics and have prospects for broad application.

  3. Environmental Assessment: Improvements to Silver Flag Training Area at Tyndall Air Force Base, Florida

    Science.gov (United States)

    2013-01-01

    Command ACM asbestos-containing materials AICUZ Air Installation Compatible Use Zone AFB Air Force Base AFI Air Force Instruction APZ Accident...T E G2/S2 Wet prairies, wet flatwoods, ditches, seepage slopes, cypress swamps White-flowered wild petunia Ruellia noctiflora E G2/S2 Wet...Procedures (SOPs) 4 or 5 of the Tyndall AFB ICRMP are required to be implemented in the event that cultural materials are discovered during

  4. Silver nanowires for highly reproducible cantilever based AFM-TERS microscopy: towards a universal TERS probe.

    Science.gov (United States)

    Walke, Peter; Fujita, Yasuhiko; Peeters, Wannes; Toyouchi, Shuichi; Frederickx, Wout; De Feyter, Steven; Uji-I, Hiroshi

    2018-04-26

    Tip-enhanced Raman scattering (TERS) microscopy is a unique analytical tool to provide complementary chemical and topographic information of surfaces with nanometric resolution. However, difficulties in reliably producing the necessary metallized scanning probe tips has limited its widespread utilisation, particularly in the case of cantilever-based atomic force microscopy. Attempts to alleviate tip related issues using colloidal or bottom-up engineered tips have so far not reported consistent probes for both Raman and topographic imaging. Here we demonstrate the reproducible fabrication of cantilever-based high-performance TERS probes for both topographic and Raman measurements, based on an approach that utilises noble metal nanowires as the active TERS probe. The tips show 10 times higher TERS contrasts than the most typically used electrochemically-etched tips, and show a reproducibility for TERS greater than 90%, far greater than found with standard methods. We show that TERS can be performed in tapping as well as contact AFM mode, with optical resolutions around or below 15 nm, and with a maximum resolution achieved in tapping-mode of 6 nm. Our work illustrates that superior TERS probes can be produced in a fast and cost-effective manner using simple wet-chemistry methods, leading to reliable and reproducible high-resolution and high-sensitivity TERS, and thus renders the technique applicable for a broad community.

  5. Partial-thickness burn wounds healing by topical treatment

    OpenAIRE

    Saeidinia, Amin; Keihanian, Faeze; Lashkari, Ardalan Pasdaran; Lahiji, Hossein Ghavvami; Mobayyen, Mohammadreza; Heidarzade, Abtin; Golchai, Javad

    2017-01-01

    Abstract Background: Burns are common event and associated with a high incidence of death, disability, and high costs. Centella asiatica (L.) is a medicinal herb, commonly growing in humid areas in several tropical countries that improve wound healing. On the basis of previous studies, we compared the efficacy of Centiderm versus silver sulfadiazine (SSD) in partial thickness burning patients. Methods: Study population comprised burn victims referred to Velayat Burning Hospital at Rasht, Iran...

  6. risk factors for wound dehiscence

    African Journals Online (AJOL)

    group B included 17 patients (minor wound dehiscence,. 26.98%), and group C ... Conclusion With regard to the wound complications following the repair of .... appear to add extra protection for wound healing. (Table 1). Median time to ...

  7. Antituberculous effect of silver nanoparticles

    International Nuclear Information System (INIS)

    Kreytsberg, G N; Gracheva, I E; Kibrik, B S; Golikov, I V

    2011-01-01

    The in vitro experiment, involving 1164 strains of the tuberculosis mycobacteria, exhibited a potentiating effect of silver nanoparticles on known antituberculous preparations in respect of overcoming drug-resistance of the causative agent. The in vitro experiment, based on the model of resistant tuberculosis, was performed on 65 white mice. An evident antituberculous effect of the nanocomposite on the basis of silver nanoparticles and isoniazid was proved. Toxicological assessment of the of nanopreparations was carried out. The performed research scientifically establishes efficacy and safety of the nanocomposite application in combination therapy of patients suffering from drug-resistant tuberculosis.

  8. Antituberculous effect of silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kreytsberg, G N; Gracheva, I E [Limited Liability Company ' Scientific and Production Association (NPO)' Likom' , 150049, Yaroslavl, Magistralnaya str., 32 (Russian Federation); Kibrik, B S [Yaroslavl State Medical Academy Russia, 150000, Yaroslavl, Revolutsionnaya str., 5 (Russian Federation); Golikov, I V, E-mail: likomm@yaroslavl.ru [Yaroslavl State Technical University Russia, 150023, Yaroslavl, Moskovskiy avenue, 88 (Russian Federation)

    2011-04-01

    The in vitro experiment, involving 1164 strains of the tuberculosis mycobacteria, exhibited a potentiating effect of silver nanoparticles on known antituberculous preparations in respect of overcoming drug-resistance of the causative agent. The in vitro experiment, based on the model of resistant tuberculosis, was performed on 65 white mice. An evident antituberculous effect of the nanocomposite on the basis of silver nanoparticles and isoniazid was proved. Toxicological assessment of the of nanopreparations was carried out. The performed research scientifically establishes efficacy and safety of the nanocomposite application in combination therapy of patients suffering from drug-resistant tuberculosis.

  9. Biomaterials for Improved Wound Healing

    Science.gov (United States)

    2013-10-01

    is silver sulphadiazine (SSD) [6-7]. SSD possesses a broad spectrum of activity against gram- positive and gram-negative bacteria as well as fungi [8... polyethylene glycol-based fibrin gel (PEGylated fibrin gel) induces vasculogenesis both in vitro and in vivo [20]. To exploit the inherent ability of fibrin as...Loaded Chitosan Microspheres Impregnated in Polyethylene Glycol Fibrin Gels (SSD-CSM-PEGylated fibrin gels) and Adipose Derived Stem Cells embedded

  10. Oral toxicity of silver ions, silver nanoparticles and colloidal silver--a review.

    Science.gov (United States)

    Hadrup, Niels; Lam, Henrik R

    2014-02-01

    Orally administered silver has been described to be absorbed in a range of 0.4-18% in mammals with a human value of 18%. Based on findings in animals, silver seems to be distributed to all of the organs investigated, with the highest levels being observed in the intestine and stomach. In the skin, silver induces a blue-grey discoloration termed argyria. Excretion occurs via the bile and urine. The following dose-dependent animal toxicity findings have been reported: death, weight loss, hypoactivity, altered neurotransmitter levels, altered liver enzymes, altered blood values, enlarged hearts and immunological effects. Substantial evidence exists suggesting that the effects induced by particulate silver are mediated via silver ions that are released from the particle surface. With the current data regarding toxicity and average human dietary exposure, a Margin of Safety calculation indicates at least a factor of five before a level of concern to the general population is reached. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Antifouling activities of β-cyclodextrin stabilized peg based silver nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Punitha, N., E-mail: punithasan@gmail.com [Department of Physics, St. Joseph’s College of Engineering, Chennai 600119 (India); Saravanan, P. [Department of Chemistry, St. Joseph’s College of Engineering, Chennai 600119 (India); Mohan, R. [Department of Physics, Surya College of Engineering and Technology, Villupuram (India); Ramesh, P.S. [Department of Physics (DDE), Annamalai University, Annamalai Nagar 608002 (India)

    2017-01-15

    Highlights: • Simple, novel and cost effective. • Functionalized Ag nanocomposites exhibit enhanced biological activity. • The SNCs were crystalline nature and shows good stability. - Abstract: Self-polishing polymer composites which release metal biocide in a controlled rate have been widely used in the design of antimicrobial agents and antifouling coatings. The present work focuses on the environmental friendly green synthesis of PEG based SNCs and their application to biocidal activity including marine biofouling. Biocompatible polymer β-CD and adhesive resistance polymer PEG were used to functionalize the SNPs and the as synthesized SNCs exhibit excellent micro fouling activities. The structural and optical properties were confirmed by XRD and UV–visible techniques respectively. The particle surface and cross sectional characteristics were examined by SEM-EDS, HR-TEM, AFM and FTIR. The surface potential was evaluated using ZP analysis and assessment of antibiofouling property was investigated using static immersion method.

  12. Antifouling activities of β-cyclodextrin stabilized peg based silver nanocomposites

    Science.gov (United States)

    Punitha, N.; Saravanan, P.; Mohan, R.; Ramesh, P. S.

    2017-01-01

    Self-polishing polymer composites which release metal biocide in a controlled rate have been widely used in the design of antimicrobial agents and antifouling coatings. The present work focuses on the environmental friendly green synthesis of PEG based SNCs and their application to biocidal activity including marine biofouling. Biocompatible polymer β-CD and adhesive resistance polymer PEG were used to functionalize the SNPs and the as synthesized SNCs exhibit excellent micro fouling activities. The structural and optical properties were confirmed by XRD and UV-visible techniques respectively. The particle surface and cross sectional characteristics were examined by SEM-EDS, HR-TEM, AFM and FTIR. The surface potential was evaluated using ZP analysis and assessment of antibiofouling property was investigated using static immersion method.

  13. Ultra-thin layer chromatography with integrated silver colloid-based SERS detection.

    Science.gov (United States)

    Wallace, Ryan A; Lavrik, Nickolay V; Sepaniak, Michael J

    2017-01-01

    Simplified lab-on-a-chip techniques are desirable for quick and efficient detection of analytes of interest in the field. The following work involves the use of deterministic pillar arrays on the micro-scale as a platform to separate compounds, and the use of Ag colloid within the arrays as a source of increased signal via surface enhanced Raman spectroscopy (SERS). One problem traditionally seen with SERS surfaces containing Ag colloid is oxidation; however, our platforms are superhydrophobic, reducing the amount of oxidation taking place on the surface of the Ag colloid. This work includes the successful separation and SERS detection of a fluorescent dye compounds (resorufin and sulforhodamine 640), fluorescent anti-tumor drugs (Adriamycin and Daunomycin), and purine and pyrimidine bases (adenine, cytosine, guanine, hypoxanthine, and thymine). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Antifouling activities of β-cyclodextrin stabilized peg based silver nanocomposites

    International Nuclear Information System (INIS)

    Punitha, N.; Saravanan, P.; Mohan, R.; Ramesh, P.S.

    2017-01-01

    Highlights: • Simple, novel and cost effective. • Functionalized Ag nanocomposites exhibit enhanced biological activity. • The SNCs were crystalline nature and shows good stability. - Abstract: Self-polishing polymer composites which release metal biocide in a controlled rate have been widely used in the design of antimicrobial agents and antifouling coatings. The present work focuses on the environmental friendly green synthesis of PEG based SNCs and their application to biocidal activity including marine biofouling. Biocompatible polymer β-CD and adhesive resistance polymer PEG were used to functionalize the SNPs and the as synthesized SNCs exhibit excellent micro fouling activities. The structural and optical properties were confirmed by XRD and UV–visible techniques respectively. The particle surface and cross sectional characteristics were examined by SEM-EDS, HR-TEM, AFM and FTIR. The surface potential was evaluated using ZP analysis and assessment of antibiofouling property was investigated using static immersion method.

  15. DNA-functionalized gold nanoparticle-based fluorescence polarization for the sensitive detection of silver ions.

    Science.gov (United States)

    Wang, Gongke; Wang, Shuangli; Yan, Changling; Bai, Guangyue; Liu, Yufang

    2018-04-05

    Despite their practical applications, Ag + ions are environmental pollutants and affect human health. So the effective detection methods of Ag + ions are imperative. Herein, we developed a simple, sensitive, selective, and cost-effective fluorescence polarization sensor for Ag + detection in aqueous solution using thiol-DNA-functionalized gold nanoparticles (AuNPs). In this sensing strategy, Ag + ions can specifically interact with a cytosine-cytosine (CC) mismatch in DNA duplexes and form stable metal-mediated cytosine-Ag + -cytosine (C-Ag + -C) base pairs. The formation of the C-Ag + -C complex results in evident changes in the molecular volume and fluorescence polarization signal. To achieve our aims, we prepared two complementary DNA strands containing C-base mismatches (probe A: 5'-SH-A 10 -TACCACTCCTCAC-3' and probe B: 5'-TCCTCACCAGTCCTA-FAM-3'). The stable hybridization between probe A and probe B occurs with the formation of the C-Ag + -C complex in the presence of Ag + ions, leading to obvious fluorescence quenching in comparison to the system without AuNP enhancement. The assay can be used to identify nanomolar levels of Ag + within 6 min at room temperature, and has extremely high specificity for Ag + , even in the presence of higher concentrations of interfering metal ions. Furthermore, the sensor was successfully applied to the detection of Ag + ions in environmental water samples and showed excellent selectivity and high sensitivity, implying its promising application in the future. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. The silver lining: towards the responsible and limited usage of silver.

    Science.gov (United States)

    Naik, K; Kowshik, M

    2017-11-01

    Silver has attracted a lot of attention as a powerful, broad spectrum and natural antimicrobial agent since the ancient times because of its nontoxic nature to the human body at low concentrations. It has been used in treatment of various infections and ulcers, storage of water and prevention of bacterial growth on the surfaces and within materials. However, there are numerous medical and health benefits of colloidal or nanosilver apart from its microbicidal ability which as yet has not been fully embraced by the medical community. These include antiplatelet activity, antioxidant effect, anticancer activity, wound healing and bone regeneration, enhancement of immunity, and increase in antibiotic efficiency. Additionally silver also provides protection against alcohol toxicity, upper respiratory tract infections and stomach ailments. Although nanosilver has been proposed for various topical applications, its usage by ingestion and inhalation remains controversial due to the lack of detailed and precise toxicity information. These beneficial properties of silver can be utilized by using silver at very low concentrations which are not harmful to the human body and environment. The following review discusses the diverse medical applications of silver and further recommends human clinical studies for its in vivo usage. #x00A9; 2017 The Society for Applied Microbiology.

  17. Highly flexible transparent thin film heaters based on silver nanowires and aluminum zinc oxides

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Hahn-Gil; Kim, Jin-Hoon; Song, Jun-Hyuk; Jeong, Unyong; Park, Jin-Woo, E-mail: jwpark09@yonsei.ac.kr

    2015-08-31

    In this work, we developed highly flexible transparent film heaters (f-TFHs) composed of Ag nanowire networks (AgNWs) and aluminum zinc oxide (AZO). Uniform AgNWs were roll-to-roll coated on polyethylene terephthalate (PET) substrates using the Mayer rod method, and AZO was sputter-deposited atop the AgNWs at room temperature. The sheet resistance (R{sub s}) and transparency (T{sub opt}) of the AZO-coated AgNWs changed only slightly compared with the uncoated AgNWs. AZO is thermally less conductive than the heat pipes, but increases the thermal efficiency of the heaters blocking the heat convection through the air. Based on Joule heating, a higher average film temperature (T{sub ave}) is attained at a fixed electric potential drop between electrodes (ϕ) as the R{sub s} of the film decreases. Our experimental results revealed that T{sub ave} of the hybrid f-TFH is higher than AgNWs when the ratio of the area coverage of AgNWs to AZO is over a certain value. When a ϕ as low as 3 V/cm was applied to 5 cm × 5 cm f-TFHs, the maximum temperature of the hybrid film was over 100 °C, which is greater than that of AgNWs by more than 30 °C. Furthermore, uniform heating throughout the surfaces is achieved in the hybrid films while heating begins in small areas where densities of the nanowires (NWs) are the highest in the bare network. The non-uniform heating decreases the lifetime of f-TFHs by forming hot spots. Cyclic bending test results indicated that the hybrid films were as flexible as the AgNWs, and the R{sub s} of the hybrid films changes only slightly until 5000 cycles. Combined with the high-throughput coating technology presented here, the hybrid films will provide a robust and scalable strategy for large-area f-TFHs with highly enhanced performance. - Highlights: • We developed highly efficient flexible thin film heaters based on Ag nanowires and AZO composites. • In the composite, AZO plays an important role as an insulation blanket to block heat loss to

  18. The application of Silver nanoparticle based SERS in diagnosing thyroid tissue

    Energy Technology Data Exchange (ETDEWEB)

    Huang Zufang; Chen Rong; Chen Guannan; Lin Duo; Xi Gangqin; Chen Yongjian; Lin Hongxin; Lei Jinping [Key Laboratory of Optoelectronic Science and Technology for Medicine, Ministry of Education, Fujian Normal University, Fuzhou 350007 (China); Li Zuanfang, E-mail: chenr@fjnu.edu.cn [Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou 350108 (China)

    2011-01-01

    Surface-enhanced Raman scattering (SERS) is proved to be a powerful analytical tool for investigation of biological tissue. In this study, SERS based on Ag nanoparticles was used to investigate the normal and cancerous thyroid tissue. Preliminary results indicated that Raman peaks and the spectra profile from both normal and cancerous tissues showed a basic similarity, obvious differences are that, first, Raman peaks 563cm{sup -1}, 1449cm{sup -1} and 1587cm{sup -1} in cancerous tissue decreased obviously compared with the normal thyroid tissue. Besides, Raman peaks 1004cm{sup -1} and 1128cm{sup -1} might be specific peaks for normal thyroid tissue, whereas 1294cm{sup -1} might attribute to specific peak for cancerous thyroid tissue. In addition, some peaks in normal thyroid tissue appeared to have shifted in cancerous tissue. Intensity ratio of 656cm{sup -1} vs. 725cm{sup -1} in normal tissue are significantly different from cancerous tissue (P<0.005), and it can be a reference for spectroscopic diagnostics of thyroid tissue. This study demonstrates that SERS can be used to monitor the changes at molecular level as well as a complementary tool in thyroid histopathology.

  19. Transparent Electrode Based on Silver Nanowires and Polyimide for Film Heater and Flexible Solar Cell.

    Science.gov (United States)

    He, Xin; Duan, Feng; Liu, Junyan; Lan, Qiuming; Wu, Jianhao; Yang, Chengyan; Yang, Weijia; Zeng, Qingguang; Wang, Huafang

    2017-11-29

    Transparent, conductive, and flexible Ag nanowire (NW)-polyimide (PI) composite films were fabricated by a facile solution method. Well-dispersed Ag NWs result in percolation networks on the PI supporting layer. A series of films with transmittance values of 53-80% and sheet resistances of 2.8-16.5 Ω/sq were investigated. To further verify the practicability of the Ag NWs-PI film in optoelectronic devices, we utilized it in a film heater and a flexible solar cell. The film heater was able to generate a temperature of 58 °C at a driving voltage of 3.5 V within 20 s, indicating its potential application in heating devices that require low power consumption and fast response. The flexible solar cell based on the composite film with a transmittance value of 71% presented a power conversion efficiency of 3.53%. These successful applications proved that the fabricated Ag NWs-PI composite film is a good candidate for application in flexible optoelectronic devices.

  20. Revitalising Silver Nitrate for Caries Management

    Directory of Open Access Journals (Sweden)

    Sherry Shiqian Gao

    2018-01-01

    Full Text Available Silver nitrate has been adopted for medical use as a disinfectant for eye disease and burned wounds. In dentistry, it is an active ingredient of Howe’s solution used to prevent and arrest dental caries. While medical use of silver nitrate as a disinfectant became subsidiary with the discovery of antibiotics, its use in caries treatment also diminished with the use of fluoride in caries prevention. Since then, fluoride agents, particularly sodium fluoride, have gained popularity in caries prevention. However, caries is an infection caused by cariogenic bacteria, which demineralise enamel and dentine. Caries can progress and cause pulpal infection, but its progression can be halted through remineralisation. Sodium fluoride promotes remineralisation and silver nitrate has a profound antimicrobial effect. Hence, silver nitrate solution has been reintroduced for use with sodium fluoride varnish to arrest caries as a medical model strategy of caries management. Although the treatment permanently stains caries lesions black, this treatment protocol is simple, painless, non-invasive, and low-cost. It is well accepted by many clinicians and patients and therefore appears to be a promising strategy for caries control, particularly for young children, the elderly, and patients with severe caries risk or special needs.

  1. Understanding and predicting the behaviour of silver base neutron absorbers under irradiations

    International Nuclear Information System (INIS)

    Desgranges, C.

    1998-01-01

    The effect of neutron irradiation induced transmutations on the swelling of AgInCd (AIC) alloys used as neutron absorber in the control rods of Pressurized Water Reactors has been studied both experimentally and theoretically. Effective atomic volumes have been determined in synthetic AgCdInSn alloys with various compositions and containing fcc and hc phases, representative of irradiated AIC (Sn is a transmutation product). Swelling is shown to result first from the transmutation of Ag into Cd and of In into Sn, both with larger effective volume than the mother atom, and second from grain boundaries precipitation of s still less dense hc phase when solid solubility of transmuted products is exceeded. For both fcc and hc phases, we have determined profiles at the temperatures in the vicinity of the operating temperature. Unusual characteristics of second phase growth at grain boundaries induced by transmutations are identified on a simple binary alloy model: kinetics is controlled by irradiation temperature which scales diffusivities and flux which scales transmutation rates, as well as by the grain size in the underlying matrix. To address the AgInCdSn alloys, a novel technique is proposed to model diffusion in multicomponent alloys. It is based on a linearization of a simple atomistic model. With a single set of parameters, for each phase, our model well reproduces our interdiffusion measurements in quaternary alloys as well as existing interdiffusion experiments in binary alloys. Finally this diffusion model implemented with a moving interface algorithm is used to model the growth of the second phase induced by transmutation in the AIC under irradiation. (authors)

  2. A Water-Based Silver-Nanowire Screen-Print Ink for the Fabrication of Stretchable Conductors and Wearable Thin-Film Transistors.

    Science.gov (United States)

    Liang, Jiajie; Tong, Kwing; Pei, Qibing

    2016-07-01

    A water-based silver-nanowire (AgNW) ink is formulated for screen printing. Screen-printed AgNW patterns have uniform sharp edges, ≈50 μm resolution, and electrical conductivity as high as 4.67 × 10(4) S cm(-1) . The screen-printed AgNW patterns are used to fabricate a stretchable composite conductor, and a fully printed and intrinsically stretchable thin-film transistor array is also realized. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Leptospermum Honey for Wound Care in an Extremely Premature Infant.

    Science.gov (United States)

    Esser, Media

    2017-02-01

    Neonatal wound care is challenging due to the fragility and vulnerable skin structure. Neonates are often left susceptible to the forces of their environment, leaving them open to infection when skin injury occurs. Leptospermum honey has been used successfully in adult patients, with evidence lacking in the neonatal population. This case demonstrates the management of a difficult-to-heal wound in a 23-week gestation infant. Selecting the proper treatment and products for wound healing is challenging, with little evidence-based research available for the treatment of neonatal wounds. Leptospermum honey and other adult-driven dressings have been used for neonatal wound care as well as other adult-driven dressings. This case demonstrates the benefits of Leptospermum honey as an option for neonatal wounds. This case presents the treatment and healing of an extensive wound of a 23-week gestation neonate using a hydrogel product initially and then transitioning to a Leptospermum honey dressing due to suboptimal healing. Results of this treatment included quick healing time, little to no scarring, and no loss of movement or function to the affected extremities. The incorporation of Leptospermum honey for wound care has the potential to promote faster wound healing, with less scarring in the neonatal population. Adult wound care principles have been applied in the face of a weak evidence base relating to neonatal-specific cases. There is a need for continued research related to moist wound healing in the neonatal population, with resulting product and practice recommendations.

  4. Highly Stable Double-Stranded DNA Containing Sequential Silver(I)-Mediated 7-Deazaadenine/Thymine Watson-Crick Base Pairs.

    Science.gov (United States)

    Santamaría-Díaz, Noelia; Méndez-Arriaga, José M; Salas, Juan M; Galindo, Miguel A

    2016-05-17

    The oligonucleotide d(TX)9 , which consists of an octadecamer sequence with alternating non-canonical 7-deazaadenine (X) and canonical thymine (T) as the nucleobases, was synthesized and shown to hybridize into double-stranded DNA through the formation of hydrogen-bonded Watson-Crick base pairs. dsDNA with metal-mediated base pairs was then obtained by selectively replacing W-C hydrogen bonds by coordination bonds to central silver(I) ions. The oligonucleotide I adopts a duplex structure in the absence of Ag(+) ions, and its stability is significantly enhanced in the presence of Ag(+) ions while its double-helix structure is retained. Temperature-dependent UV spectroscopy, circular dichroism spectroscopy, and ESI mass spectrometry were used to confirm the selective formation of the silver(I)-mediated base pairs. This strategy could become useful for preparing stable metallo-DNA-based nanostructures. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Fluorometric immunoassay for human serum albumin based on its inhibitory effect on the immunoaggregation of quantum dots with silver nanoparticles

    Science.gov (United States)

    Marukhyan, Seda S.; Gasparyan, Vardan K.

    2017-02-01

    Quantitative determination of HSA was conducted by competitive immunoassay. Inhibition of aggregation of antibody conjugated quantum dots (QD) with albumin conjugated silver nanoparticles (AgNPs) in the presence of HSA was conducted. If antibody-loaded CdSe QDs aggregate with HSA-coated silver nanoparticles the distance between the two kinds of nanoparticles will be reduced enough to cause fluorescence resonance energy transfer (FRET). In this case the yellow fluorescence of the Ab-QDs is quenched. However if HSA (antigen) is added to the Ab-QDs their surface will be blocked and they cannot aggregate any longer with the HSA-AgNPs. Hence, fluorescence will not be quenched. The drop of the intensity of fluorescence (peaking at 570 nm) is inversely correlated with the concentration of HSA in the sample. The method allows to determine HSA in the 30-600 ng·mL-1 concentration range.

  6. Reusable fluorescent sensor for captopril based on energy transfer from photoluminescent graphene oxide self-assembly multilayers to silver nanoparticles.

    Science.gov (United States)

    Sun, Xiangying; Liu, Bin; Li, Shuchun; Li, Fang

    2016-05-15

    In this work we designed a self-assembly multilayers, in which photoluminescent graphene oxide was employed as a fluorescence probe. This multilayers film can effectively recognize captopril by resonance energy transfer from graphite oxide to silver nanoparticles. A new interfacial sensing method for captopril with high signal to noise ratio was established, by means of that multilayers was quenched by silver nanoparticles and subsequently recovered by adding captopril. The linear relation between intensity and captopril concentration was good, and the detection limit was found to be 0.1578 μM. Also, this novel detection platform demonstrated intriguing reusable properties, and the sensor could be repeated more than ten times without obviously losing its sensing performance. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Antibacterial potency of V.A.C. GranuFoam Silver(®) Dressing.

    Science.gov (United States)

    Sachsenmaier, Saskia; Peschel, Andreas; Ipach, Ingmar; Kluba, Torsten

    2013-10-01

    V.A.C.(®) GranuFoam™ therapy is regularly used in the surgical therapy of infected wounds and soft tissue injuries. Silver nanoparticles can destroy bacterial cell walls and inhibit enzymes for cell replication. Silver dressings are therefore successfully used for many indications in wound therapy. In this study, we investigated the antimicrobial potency of ionic silver released from the silver-coated V.A.C.(®) GranuFoam™ during vacuum therapy. Silver dressing was exposed to agar plates populated with bacteria to measure silver release. A total of 15 agar plates colonised with either Staphylococcus aureus populations or with Staphylococcus epidermidis, were loaded with V.A.C. GranuFoam Silver(®) Dressing polyurethane foam (KCI, San Antonio, Texas). Each of 13 pieces of silver-coated foam was applied to an agar plate. Two plates were loaded with conventional black foam without any coating. After connecting to a vacuum pump, the vacuum therapy of the 15 plates lasted 5 days. The zone of inhibition of bacterial growth around th