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Sample records for dye micelle hydrogels

  1. Polymer Micelles Laden Hydrogel Contact Lenses for Ophthalmic Drug Delivery.

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    Hu, Xiaohong; Tan, Huaping; Chen, Pin; Wang, Xin; Pang, Juan

    2016-06-01

    Hydrogel contact lens is an attractive drug carrier for the delivery of ophthalmic drugs. But limited drug loading capacity and burst release restricted its application in this field. Polymer micelle laden hydrogel contact lenses were designed for ophthalmic drug delivery in the work. β-CD/PAA/PEG ternary system was chosen to form polymer micelle. The micelle size could be adjusted by β-CD content and PAA/PEG concentration. The zeta potential of micelle was irrelevant to β-CD content, but influenced by PAA/PEG concentration. The absorbed drug concentration in micelle solution depended on both β-CD content and PAA/PEG concentration. Polymer micelle laden hydrogels were obtained by radical polymerization in situ. The transparency of polymer micelle laden hydrogel declined with PAA/PEG concentration increasing. The equilibrium water content and water loss showed that polymer micelle laden hydrogel with higher PAA/PEG concentration was in a higher swollen state. The dynamic viscoelastic properties howed that all polymer micelle laden hydrogels had some characteristics of crosslinked elastomers. The surface structure of freeze dried composite hydrogels was different from freeze dried pure hydrogel. The drug loading and releasing behaviors were detected to evaluate the drug loading and releasing capacity of hydrogels using orfloxacin and puerarin as model drugs. The results indicated the polymer micelle in hydrogel could hold or help to hold some ophthalmic drugs, and slow down orfloxacin release speed or keep puerarin stably stay for a time in hydrogels. In the end, it was found that the transparency of composite hydrogel became better after the hydrogel had been immersed in PBS for several weeks.

  2. Photophysical properties of pyronin dyes in reverse micelles of AOT

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    Bayraktutan, Tuğba; Meral, Kadem; Onganer, Yavuz, E-mail: yonganer@atauni.edu.tr

    2014-01-15

    The photophysical properties of pyronin B (PyB) and pyronin Y (PyY) in reverse micelles formed with water/sodium bis (2-ethyl-1-hexyl) sulfosuccinate (AOT)/n-heptane were investigated by UV–vis absorption, steady-state and time-resolved fluorescence spectroscopy techniques. This study was carried out a wide range of reverse micelle sizes, with hydrodynamic radii ranging from 1.85 to 9.38 nm. Significant photophysical parameters as band shifts, fluorescence quantum yields and fluorescence lifetimes were determined to understand how photophysical and spectroscopic features of the dye compounds were affected by the variation of reverse micelle sizes. In this regard, control of reverse micelle size by changing W{sub 0}, the molar ratio of water to surfactant, allowed tuning the photophysical properties of the dyes in organic solvent via reverse micelle. Non-fluorescent H-aggregates of pyronin dyes were observed for the smaller reverse micelles whereas an increase in the reverse micelle size induced an increment in the amount of dye monomers instead of dye aggregates. Thus, the fluorescence intensities of the dyes were improved by increasing W{sub 0} due to the predomination of the fluorescent dye monomers. As a result, the fluorescence quantum yields also increased. The fluorescence lifetimes of the dyes in the reverse micelles were determined by the time-resolved fluorescence decay studies. Evaluation of the fluorescence lifetimes calculated for pyronin dyes in the reverse micelles showed that the size of reverse micelle affected the fluorescence lifetimes of pyronin dyes. -- Highlights: • The photophysical properties of pyronin dyes were examined by spectroscopic techniques. • Optical properties of the dyes were tuned by changing of W{sub 0} values. • The fluorescence lifetime and quantum yield values of the dyes in reverse micelles were discussed.

  3. Mechano-responsive hydrogels crosslinked by reactive block copolymer micelles

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    Xiao, Longxi

    Hydrogels are crosslinked polymeric networks that can swell in water without dissolution. Owing to their structural similarity to the native extracelluar matrices, hydrogels have been widely used in biomedical applications. Synthetic hydrogels have been designed to respond to various stimuli, but mechanical signals have not incorporated into hydrogel matrices. Because most tissues in the body are subjected to various types of mechanical forces, and cells within these tissues have sophisticated mechano-transduction machinery, this thesis is focused on developing hydrogel materials with built-in mechano-sensing mechanisms for use as tissue engineering scaffolds or drug release devices. Self-assembled block copolymer micelles (BCMs) with reactive handles were employed as the nanoscopic crosslinkers for the construction of covalently crosslinked networks. BCMs were assembled from amphiphilic diblock copolymers of poly(n-butyl acrylate) and poly(acrylic acid) partially modified with acrylate. Radical polymerization of acrylamide in the presence of micellar crosslinkers gave rise to elastomeric hydrogels whose mechanical properties can be tuned by varying the BCM composition and concentration. TEM imaging revealed that the covalently integrated BCMs underwent strain-dependent reversible deformation. A model hydrophobic drug, pyrene, loaded into the core of BCMs prior to the hydrogel formation, was dynamically released in response to externally applied mechanical forces, through force-induced reversible micelle deformation and the penetration of water molecules into the micelle core. The mechano-responsive hydrogel has been studied for tissue repair and regeneration purposes. Glycidyl methacrylate (GMA)-modified hyaluronic acid (HA) was photochemically crosslinked in the presence of dexamethasone (DEX)-loaded crosslinkable BCMs. The resultant HA gels (HAxBCM) contain covalently integrated micellar compartments with DEX being sequestered in the hydrophobic core. Compared

  4. Near-Infrared Squaraine Dye Encapsulated Micelles for in Vivo Fluorescence and Photoacoustic Bimodal Imaging.

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    Sreejith, Sivaramapanicker; Joseph, James; Lin, Manjing; Menon, Nishanth Venugopal; Borah, Parijat; Ng, Hao Jun; Loong, Yun Xian; Kang, Yuejun; Yu, Sidney Wing-Kwong; Zhao, Yanli

    2015-06-23

    Combined near-infrared (NIR) fluorescence and photoacoustic imaging techniques present promising capabilities for noninvasive visualization of biological structures. Development of bimodal noninvasive optical imaging approaches by combining NIR fluorescence and photoacoustic tomography demands suitable NIR-active exogenous contrast agents. If the aggregation and photobleaching are prevented, squaraine dyes are ideal candidates for fluorescence and photoacoustic imaging. Herein, we report rational selection, preparation, and micelle encapsulation of an NIR-absorbing squaraine dye (D1) for in vivo fluorescence and photoacoustic bimodal imaging. D1 was encapsulated inside micelles constructed from a biocompatible nonionic surfactant (Pluoronic F-127) to obtain D1-encapsulated micelles (D1(micelle)) in aqueous conditions. The micelle encapsulation retains both the photophysical features and chemical stability of D1. D1(micelle) exhibits high photostability and low cytotoxicity in biological conditions. Unique properties of D1(micelle) in the NIR window of 800-900 nm enable the development of a squaraine-based exogenous contrast agent for fluorescence and photoacoustic bimodal imaging above 820 nm. In vivo imaging using D1(micelle), as demonstrated by fluorescence and photoacoustic tomography experiments in live mice, shows contrast-enhanced deep tissue imaging capability. The usage of D1(micelle) proven by preclinical experiments in rodents reveals its excellent applicability for NIR fluorescence and photoacoustic bimodal imaging.

  5. Specific interactions within micelle microenvironment in different charged dye/surfa

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    Adina Roxana Petcu

    2016-01-01

    Full Text Available The interactions of two ionic dyes, Crystal Violet and Methyl Orange, with different charged surfactants and also with a nonionic surfactant were investigated using surface tension measurements and visible spectroscopy in pre-micellar and post-micellar regions. It was found that for the water dominant phase systems the dye was localized between the polar heads, at the exterior of the direct micelle shells for all the systems. For the oil dominant phase systems, in case of the same charged dye/surfactant couples, the dye was localized in the micelle shell between the hydrocarbon chain of the surfactant nearby the hydrophilic head groups while for nonionic surfactant and oppositely charged dye/surfactant, localization of dye was between the oxyethylenic head groups towards the interior of the micelle core. Mixed aggregates of the dye and surfactant (below the critical micellar concentration of cationic surfactant, dye-surfactant ion pair and surfactant-micelles were present. The values of equilibrium constants (for TX-114/MO and TX-114/CV systems were 0.97 and 0.98, respectively, partition coefficients between the micellar and bulk water phases and standard free energy (for the nonionic systems were −12.59 kJ/mol for MO and −10.97 kJ/mol for CV were calculated for all the studied systems. The partition processes were exothermic and occurred spontaneously.

  6. Preparation of Graphene Oxide-Based Hydrogels as Efficient Dye Adsorbents for Wastewater Treatment

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    Guo, Haiying; Jiao, Tifeng; Zhang, Qingrui; Guo, Wenfeng; Peng, Qiuming; Yan, Xuehai

    2015-06-01

    Graphene oxide (GO) sheets exhibit superior adsorption capacity for removing organic dye pollutants from an aqueous environment. In this paper, the facile preparation of GO/polyethylenimine (PEI) hydrogels as efficient dye adsorbents has been reported. The GO/PEI hydrogels were achieved through both hydrogen bonding and electrostatic interactions between amine-rich PEI and GO sheets. For both methylene blue (MB) and rhodamine B (RhB), the as-prepared hydrogels exhibit removal rates within about 4 h in accordance with the pseudo-second-order model. The dye adsorption capacity of the hydrogel is mainly attributed to the GO sheets, whereas the PEI was incorporated to facilitate the gelation process of GO sheets. More importantly, the dye-adsorbed hydrogels can be conveniently separated from an aqueous environment, suggesting potential large-scale applications of the GO-based hydrogels for organic dye removal and wastewater treatment.

  7. Micelles assembled with carbocyanine dyes for theranostic near-infrared fluorescent cancer imaging and photothermal therapy.

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    Yang, Hong; Mao, Huajian; Wan, Zhihui; Zhu, Aijun; Guo, Miao; Li, Yanli; Li, Xinming; Wan, Jiangling; Yang, Xiangliang; Shuai, Xintao; Chen, Huabing

    2013-12-01

    It is an emerging focus to explore a theranostic nanocarrier for simultaneous cancer imaging and therapy. Herein, we demonstrate a theranostic micelle system for cancer near infrared fluorescent (NIRF) imaging with enhanced signal to noise ratio and superior photothermal therapy. The copolymers consisting of monomethoxy poly(ethylene glycol) and alkylamine-grafted poly(L-aspartic acid) are assembled with carbocyanine dyes into theranostic micelles, which exhibit small size, high loading capacity, good stability, sustained release behavior, and enhanced cellular uptake. The micelles achieve the preferable biodistribution and long-term retention of carbocyanine dyes at tumor, which result in enhanced NIRF imaging by generating stable retention of NIRF signals at both hypervascular and hypovascular tumors during a long-term imaging period of up to 8 day, accompanying with negligible noise at normal tissues. The photostability of carbocyanine dye (Cypate) plays an important role for long-term cancer imaging with enhanced SNR. Moreover, the micelles exhibit severe photothermal damage on cancer cells via the destabilization of subcellular organelles upon photoirradiation, causing superior photothermal tumor regress. The micelles act as a powerful theranostic nanocarrier for simultaneous cancer imaging with high contrast and superior photothermal therapy.

  8. Injectable polypeptide micelles that form radiation crosslinked hydrogels in situ for intratumoral radiotherapy.

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    Schaal, Jeffrey L; Li, Xinghai; Mastria, Eric; Bhattacharyya, Jayanta; Zalutsky, Michael R; Chilkoti, Ashutosh; Liu, Wenge

    2016-04-28

    Intratumoral radiation therapy - 'brachytherapy' - is a highly effective treatment for solid tumors, particularly prostate cancer. Current titanium seed implants, however, are permanent and are limited in clinical application to indolent malignancies of low- to intermediate-risk. Attempts to develop polymeric alternatives, however, have been plagued by poor retention and off-target toxicity due to degradation. Herein, we report on a new approach whereby thermally sensitive micelles composed of an elastin-like polypeptide (ELP) are labeled with the radionuclide (131)I to form an in situ hydrogel that is stabilized by two independent mechanisms: first, body heat triggers the radioactive ELP micelles to rapidly phase transition into an insoluble, viscous coacervate in under 2 min; second, the high energy β-emissions of (131)I further stabilize the depot by introducing crosslinks within the ELP depot over 24h. These injectable brachytherapy hydrogels were used to treat two aggressive orthotopic tumor models in athymic nude mice: a human PC-3 M-luc-C6 prostate tumor and a human BxPc3-luc2 pancreatic tumor model. The ELP depots retained greater than 52% and 70% of their radioactivity through 60 days in the prostate and pancreatic tumors with no appreciable radioactive accumulation (≤ 0.1% ID) in off-target tissues after 72h. The (131)I-ELP depots achieved >95% tumor regression in the prostate tumors (n=8); with a median survival of more than 60 days compared to 12 days for control mice. For the pancreatic tumors, ELP brachytherapy (n=6) induced significant growth inhibition (p=0.001, ANOVA) and enhanced median survival to 27 days over controls.

  9. Nanocomposite hydrogel incorporating gold nanorods and paclitaxel-loaded chitosan micelles for combination photothermal-chemotherapy.

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    Zhang, Nan; Xu, Xuefan; Zhang, Xue; Qu, Ding; Xue, Lingjing; Mo, Ran; Zhang, Can

    2016-01-30

    Development of combination photothermal-chemotherapy platform is of great interest for enhancing antitumor efficacy and inhibiting tumor recurrence, which supports selective and dose-controlled delivery of heat and anticancer drugs to tumor. Here, an injectable nanocomposite hydrogel incorporating PEGylated gold nanorods (GNRs) and paclitaxel-loaded chitosan polymeric micelles (PTX-M) is developed in pursuit of improved local tumor control. After intratumoral injection, both GNRs and PTX-M can be simultaneously delivered and immobilized in the tumor tissue by the thermo-sensitive hydrogel matrix. Exposure to the laser irradiation induces the GNR-mediated photothermal damage confined to the tumor with sparing the surrounding normal tissue. Synergistically, the co-delivered PTX-M shows prolonged tumor retention with the sustained release of anticancer drug to efficiently kill the residual tumor cells that evade the photothermal ablation due to the heterogeneous heating in the tumor region. This combination photothermal-chemotherapy presents superior effects on suppressing the tumor recurrence and prolonging the survival in the Heps-bearing mice, compared to the photothermal therapy alone.

  10. pH-sensitive wax emulsion copolymerization with acrylamide hydrogel using gamma irradiation for dye removal

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    Ghobashy, Mohamed Mohamady; Elhady, Mohamed., A.

    2017-05-01

    Emulsion polymerization is an efficient method for the production of new wax-hydrogel matrices of cetyl alcohol: stearic acid wax and acrylamide hydrogel using triethylamine (TEA) as an emulsifier. A cross-linking reaction occurred when a mixture of wax-hydrogel solution was irradiated with gamma rays at a dose of 20 kGy. The gelation percentage of the matrices (CtOH-StA/PAAm) was 86%, which indicates that a sufficiently high conversion occurred in these new wax-hydrogel matrices. The ability of PAAm and CtOH-StA/PAAm as an adsorbent for dye removal was investigated. The removal of three reactive dyes, namely Remazol Red (RR), Amido Black (AB), and Toluidine Blue (TB), from aqueous solutions depends on the pH of the dye solution. Removal efficiency was investigated by UV spectrophotometry, and the results showed the affinity of the wax hydrogel to adsorb TB was 98% after 320 min. Fourier transform infrared-attenuated total reflectance spectra confirmed the cross-linking process involved between the chains of wax and hydrogel; furthermore, scanning electron microscopy images showed that the wax and hydrogel were completely miscible to form a single matrix. Swelling measurements showed the high affinity of adsorbed dyes from aqueous solutions at different pH values to the wax-hydrogel network; the highest swelling values of 13.05 and 8.24 (g/g) were observed at pH 10 and 6, respectively

  11. Non-diffusing radiochromic micelle gel

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    Jordan, Kevin; Sekimoto, Masaya

    2010-11-01

    The addition of Laponite, a synthetic clay nanoparticle material to radiochromic leuco Malachite Green micelle hydrogel eliminates diffusion of the cationic dye by electrostatic binding. The clay nanoparticles also increased dose sensitivity ten-fold relative to the parent gel formulation. This material is a suitable 3D water equivalent dosimeter with optical CT readout.

  12. USEBILITY OF HYDROGELS IN ADSORPTION TECHNOLOGHY FOR REMOVAL OF HEAVY METAL AND DYE

    Directory of Open Access Journals (Sweden)

    AÇIKEL Safiye Meriç

    2016-05-01

    Full Text Available Heavy metals and Dyes are very toxic and nonbiodegradable in waste waters to cause adverse health effects in human body and to induce irreversible pollution. Adsorption offers many potential advantages for removal of toxic heavy metals being flexibility in design and operation, high-quality treated effluent, reversible nature for multiple uses, and many commercially available adsorbent materials, such as activated carbon, zeolite, clay, sawdust, bark, biomass, lignin, chitosan and other polymer adsorbents. Compared to conventional adsorbent materials above, hydrogelbased adsorbents recently have attracted special attention to their highly potential for effective removal of heavy metals and dyes. Hydrogels are named “Hydrophilic Polymer” because of care for water. Hydrogels is not solved in water; however they have been swollen to their balance volume. Because of this swell behavior, they can adsorb big quantity of water in this structure. So they can term of “three sized polymers” due to protect their existing shape [9]. Hydrogels with porous structures and chemically-responsive functional groups, enable to readily capture metal ions and dyes from wastewater. Hydrogels with porous structures and chemically-responsive functional groups, enable to readily capture metal ions and dyes from wastewater. In adsorption applications, hydrogels are used in water purification, heavy metal/dying removing, controlled fertilizer released, ion exchange applications, chromatographic applications, dilute extractions, waste water treatments. This article general inform about usage of hydrogels in Dye and Heavy Metal adsorption.

  13. Assessment of alginate hydrogel degradation in biological tissue using viscosity-sensitive fluorescent dyes

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    Shkand, Tatiana V.; Chizh, Mykola O.; Sleta, Iryna V.; Sandomirsky, Borys P.; Tatarets, Anatoliy L.; Patsenker, Leonid D.

    2016-12-01

    The main goal of this study is to investigate a combination of viscosity-sensitive and viscosity-insensitive fluorescent dyes to distinguish different rheological states of hydrogel based biostructural materials and carriers in biological tissues and to assess their corresponding location areas. The research is done in the example of alginate hydrogel stained with viscosity-sensitive dyes Seta-470 and Seta-560 as well as the viscosity-insensitive dye Seta-650. These dyes absorb/emit at 469/518, 565/591 and 651/670 nm, respectively. The rheological state of the alginate, the area of the fluorescence signal and the mass of the dense alginate versus the calcium gluconate concentration utilized for alginate gelation were studied in vitro. The most pronounced change in the fluorescence signal area was found at the same concentrations of calcium gluconate (below ~1%) as the change in the alginate plaque mass. The stained alginate was also implanted in situ in rat hip and myocardium and monitored using fluorescence imaging. In summary, our data indicate that the viscosity sensitive dye in combination with the viscosity-insensitive dye allow tracking the biodegradation of the alginate hydrogel and determining the rheological state of hydrogel in biological tissue, which both should have relevance for research and clinical applications. Using this method we estimated the half-life of the dense alginate hydrogel in a rat hip to be in the order of 4 d and about 6-8 d in rat myocardium. The half-life of the dense hydrogel in the myocardium was found to be long enough to prevent aneurysm rupture of the left ventricle wall, one of the more severe complications of the early post-infarction period.

  14. Investigation of citric acid-glycerol based pH-sensitive biopolymeric hydrogels for dye removal applications: A green approach.

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    Franklin, D S; Guhanathan, S

    2015-11-01

    Hydrogels are three dimensional polymeric structure with segments of hydrophilic groups. The special structure of hydrogels facilitates the diffusion of solutes into the interior network and possess numerous ionic and non-ionic functional groups, which can absorb or trap ionic dyes from waste water. The present investigation was devoted to the synthesis of a series of citric acid and glycerol based pH sensitive biopolymeric hydrogels using a solventless green approach via condensation polymerization in the presence of acidic medium. The formations of hydrogels were confirmed using various spectral investigations viz., FT-IR, (1)H and (13)C NMR. The thermal properties of various hydrogels have been studied using TGA, DTA and DSC analysis. The rationalized relationship was noticed with increasing of pH from 4.0 to 10.0. The surface morphologies of hydrogels were analyzed using SEM technique which was well supported from the results of swelling studies. Methylene blue has been selected as a cationic dye for its removal from various environmental sources using pH-sensitive biopolymeric hydrogels. The results of dye removal revealed that glycerol based biopolymeric hydrogels have shown an excellent dye removal capacity. Hence, the synthesized pH sensitive biopolymeric hydrogels have an adaptability with pH tuned properties might have greater potential opening in various environmental applications viz., metal ion removal, agrochemical release, purification of water, dye removal etc.

  15. Chitosan-based hydrogel for dye removal from aqueous solutions: Optimization of the preparation procedure

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    Gioiella, Lucia; Altobelli, Rosaria; de Luna, Martina Salzano; Filippone, Giovanni

    2016-05-01

    The efficacy of chitosan-based hydrogels in the removal of dyes from aqueous solutions has been investigated as a function of different parameters. Hydrogels were obtained by gelation of chitosan with a non-toxic gelling agent based on an aqueous basic solution. The preparation procedure has been optimized in terms of chitosan concentration in the starting solution, gelling agent concentration and chitosan-to-gelling agent ratio. The goal is to properly select the material- and process-related parameters in order to optimize the performances of the chitosan-based dye adsorbent. First, the influence of such factors on the gelling process has been studied from a kinetic point of view. Then, the effects on the adsorption capacity and kinetics of the chitosan hydrogels obtained in different conditions have been investigated. A common food dye (Indigo Carmine) has been used for this purpose. Noticeably, although the disk-shaped hydrogels are in the bulk form, their adsorption capacity is comparable to that reported in the literature for films and beads. In addition, the bulk samples can be easily separated from the liquid phase after the adsorption process, which is highly attractive from a practical point of view. Compression tests reveal that the samples do not breakup even after relatively large compressive strains. The obtained results suggest that the fine tuning of the process parameters allows the production of mechanical resistant and highly adsorbing chitosan-based hydrogels.

  16. Photophysical study of a charge transfer oxazole dye in micelles: Role of surfactant headgroups

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    Maiti, Jyotirmay [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India); Sarkar, Yeasmin; Parui, Partha Pratim [Department of Chemistry, Jadavpur University, Kolkata 700032 (India); Chakraborty, Sandipan [Department of Microbiology, University of Calcutta, Kolkata 700019 (India); Biswas, Suman [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India); Das, Ranjan, E-mail: ranjan.das68@gmail.com [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India)

    2015-07-15

    Photophysics of 5-(4′′-dimethylaminophenyl)-2-(4′-sulfophenyl)oxazole, sodium salt (DMO) which undergoes intramolecular charge transfer in the excited state was studied in micelles. In the cationic and the nonionic micelles, significantly higher fluorescence quantum yield is observed in comparison to the anionic micelles, due to much lower accessibility of DMO to the water molecules in the former micelles than the latter. Time-resolved fluorescence decays were characterized by a fast (τ{sub 1}) and a slow (τ{sub 2}) component of decay in all the micelles. The fast decay component (τ{sub 1}) increases significantly in going from the anionic micelles to the cationic micelles, because of the poorly hydrated headgroup region of the latter micelles compared to the former. Furthermore, much higher value of the slow component of decay (τ{sub 2}) is observed for the cationic and the neutral micelles than the anionic micelles. This is attributed to the increased penetration of water molecules into the micellar core of the anionic micelles compared to the cationic and the neutral micelles. - Highlights: • Photophysics of the fluorophore are remarkably different in the cationic and the anionic micelles. • Differential hydration of the surfactant headgroups gives rise to significantly different fluorescence quantum yield and lifetime in oppositely charged micelles. • Electrostatic interactions fine tune location of the fluorophore in the micelle–water interface of ionic micelles.

  17. Synthesis of interpenetrating network hydrogel from poly(acrylic acid-co-hydroxyethyl methacrylate) and sodium alginate: modeling and kinetics study for removal of synthetic dyes from water.

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    Mandal, Bidyadhar; Ray, Samit Kumar

    2013-10-15

    Several interpenetrating network (IPN) hydrogels were made by free radical in situ crosslink copolymerization of acrylic acid (AA) and hydroxy ethyl methacrylate in aqueous solution of sodium alginate. N,N'-methylenebisacrylamide (MBA) was used as comonomer crosslinker for making these crosslink hydrogels. All of these hydrogels were characterized by carboxylic content, FTIR, SEM, XRD, DTA-TGA and mechanical properties. Swelling, diffusion and network parameters of the hydrogels were studied. These hydrogels were used for adsorption of two important synthetic dyes, i.e. Congo red and methyl violet from water. Isotherms, kinetics and thermodynamics of dye adsorption by these hydrogels were also studied.

  18. Synthesis and Characterization of Modified Chitosan-based Novel Superabsorbent hydrogel: Swelling and Dye Adsorption behavior

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    Oladipo, Akeem Adeyemi

    2011-01-01

    ABSTRACT: Lately, a wide application of eco-friendly polysaccharide-based hydrogels in waste water treatment has received enormous attention in the literature. Particularly, the development of super swelling chitosan-based materials as versatile and useful adsorbent polymeric agent is an expanding area in the field of adsorption science today. The effluents containing dye materials from the processing industries are washed off into rivers and lakes which can be very harmful to creatures. Low...

  19. Synthesis and Characterization of Modified Chitosan-based Novel Superabsorbent hydrogel: Swelling and Dye Adsorption behavior

    OpenAIRE

    Oladipo, Akeem Adeyemi

    2011-01-01

    ABSTRACT: Lately, a wide application of eco-friendly polysaccharide-based hydrogels in waste water treatment has received enormous attention in the literature. Particularly, the development of super swelling chitosan-based materials as versatile and useful adsorbent polymeric agent is an expanding area in the field of adsorption science today. The effluents containing dye materials from the processing industries are washed off into rivers and lakes which can be very harmful to creatures. Low...

  20. Small angle neutron scattering study of complex coacervate micelles and hydrogels formed from ionic diblock and triblock copolymers.

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    Krogstad, Daniel V; Choi, Soo-Hyung; Lynd, Nathaniel A; Audus, Debra J; Perry, Sarah L; Gopez, Jeffrey D; Hawker, Craig J; Kramer, Edward J; Tirrell, Matthew V

    2014-11-13

    A complex coacervate is a fluid phase that results from the electrostatic interactions between two oppositely charged macromolecules. The nature of the coacervate core structure of hydrogels and micelles formed from complexation between pairs of diblock or triblock copolymers containing oppositely charged end-blocks as a function of polymer and salt concentration was investigated. Both ABA triblock copolymers of poly[(allyl glycidyl ether)-b-(ethylene oxide)-b-(allyl glycidyl ether)] and analogous poly[(allyl glycidyl ether)-b-(ethylene oxide)] diblock copolymers, which were synthesized to be nearly one-half of the symmetrical triblock copolymers, were studied. The poly(allyl glycidyl ether) blocks were functionalized with either guanidinium or sulfonate groups via postpolymerization modification. Mixing of oppositely charged block copolymers resulted in the formation of nanometer-scale coacervate domains. Small angle neutron scattering (SANS) experiments were used to investigate the size and spacing of the coacervate domains. The SANS patterns were fit using a previously vetted, detailed model consisting of polydisperse core-shell micelles with a randomly distributed sphere or body-centered cubic (BCC) structure factor. For increasing polymer concentration, the size of the coacervate domains remained constant while the spatial extent of the poly(ethylene oxide) (PEO) corona decreased. However, increasing salt concentration resulted in a decrease in both the coacervate domain size and the corona size due to a combination of the electrostatic interactions being screened and the shrinkage of the neutral PEO blocks. Additionally, for the triblock copolymers that formed BCC ordered domains, the water content in the coacervate domains was calculated to increase from approximately 16.8% to 27.5% as the polymer concentration decreased from 20 to 15 wt %.

  1. Polyacrylamide-Phytic Acid-Polydopamine Conducting Porous Hydrogel for Efficient Removal of Water-Soluble Dyes.

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    Zhao, Zhen; Li, Leijiao; Geleta, Girma Selale; Ma, Lina; Wang, Zhenxin

    2017-08-11

    Removal of toxic dyes from wastewater has become a hot topic in both academic and industrial fields since there is growing concern about the threat of sewage to human health. Herein, we demonstrate that the three-dimensional porous polyacrylamide-phytic acid-polydopamine (termed as PAAM/PA/PDA) hydrogel can be served as reusable adsorbent with high efficiency for either anionic or cationic dyes. Using methyl blue (MB), methylene blue (YMB), methyl violet (MV) and neutral red (NR) as model dyes, we investigate the effect of pH, temperature, dye concentration, and PAAM/PA/PDA hydrogel mass on the adsorption. The experimental maximum adsorption capacities are more than 350.67 mg g(-1) for four selected dyes. Adsorption kinetic and thermodynamic analysis suggests that the dyes are adsorbed on the PAAM/PA/PDA hydrogel through the strong π-π stacking and anion-cation interaction, and the adsorption process satisfies a pseudo-second-order model. Furthermore, the free-standing PAAM/PA/PDA hydrogel can be easily removed from water after adsorption process, and regenerated by adjusting solution pH values.

  2. Gum karaya based hydrogel nanocomposites for the effective removal of cationic dyes from aqueous solutions

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    Mittal, Hemant; Maity, Arjun; Ray, Suprakas Sinha

    2016-02-01

    Biodegradable hydrogel nanocomposites (HNC) of gum karaya (GK) grafted with poly(acrylic acid) (PAA) incorporated silicon carbide nanoparticles (SiC NPs) were synthesized using the in situ graft copolymerization method and tested for the adsorption of cationic dyes from aqueous solution. The structure and morphology of the HNC were characterized using different spectroscopic and microscopic techniques. The results showed that the surface area and porosity of the hydrogel polymer significantly increased after nanocomposite formation with SiC NPs. The HNC was employed for the removal of cationic dyes, i.e., malachite green (MG) and rhodamine B (RhB) from the aqueous solution. The HNC was found to remove 91% (MG) and 86% (RhB) of dyes with a polymer dose of 0.5 and 0.6 g l-1 in neutral medium, respectively. The adsorption process was found to be highly pH dependent and followed the pseudo-second-order rate model. The adsorption isotherm data fitted well with the Langmuir adsorption isotherm with a maximum adsorption capacity of 757.57 and 497.51 mg g-1 for MG and RhB, respectively. Furthermore, the HNC was demonstrated as a versatile adsorbent for the removal of both cationic and anionic dyes from the simulated wastewater. The HNC showed excellent regeneration capacity and was successfully used for the three cycles of adsorption-desorption. In summary, the HNC has shown its potential as an environment friendly and efficient adsorbent for the adsorption of cationic dyes from contaminated water.

  3. Novel biocompatible hydrogel nanoparticles: generation and size-tuning of nanoparticles by the formation of micelle templates obtained from thermo-responsive monomers mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Khandadash, Raz; Machtey, Victoria [Bar Ilan University, Department of Chemistry (Israel); Shainer, Inbal [Tel-Aviv University, Department of Neurobiology, The George S. Wise Faculty of Life Sciences (Israel); Gottlieb, Hugo E. [Bar Ilan University, Department of Chemistry (Israel); Gothilf, Yoav [Tel-Aviv University, Department of Neurobiology, The George S. Wise Faculty of Life Sciences, and Sagol School of Neuroscience (Israel); Ebenstein, Yuval [Tel Aviv University, Raymond and Beverly Sackler Faculty of Exact Sciences, School of Chemistry (Israel); Weiss, Aryeh [Bar Ilan University, School of Engineering (Israel); Byk, Gerardo, E-mail: gerardo.byk@biu.ac.il [Bar Ilan University, Department of Chemistry (Israel)

    2014-12-15

    Biocompatible hydrogel nanoparticles are prepared by polymerization and cross-linking of N-isopropyl acrylamide in a micelle template formed by block copolymers macro-monomers at high temperature. Different monomer ratios form, at high temperature, well-defined micelles of different sizes which are further polymerized leading to nanoparticles with varied sizes from 20 to 390 nm. Physico-chemical characterization of the nanoparticles demonstrates their composition and homogeneity. The NPs were tested in vitro and in vivo biocompatibility assays, and their lack of toxicity was proven. The NPs can be labeled with fluorescent probes, and their intracellular fate can be visualized and quantified using confocal microscopy. Their uptake by live stem cells and distribution in whole developing animals is reported. On the basis of our results, a mechanism of nanoparticle formation is suggested. The lack of toxicity makes these nanoparticles especially attractive for biological applications such as screening and bio-sensing.

  4. Novel composite sorbent AAm/MA hydrogels containing starch and kaolin for water sorption and dye uptake

    Indian Academy of Sciences (India)

    Erdener Karadağ; Fulya Topaç; Semıha Kundakci; ÖMER Bariş Üzüm

    2014-12-01

    A novel polymer/clay composite sorbent based on acrylamide/maleic acid, starch and clay such as kaolin was synthesized with free radical solution polymerization by using ammonium persulfate/,,','-tetramethylethylenediamine as redox initiating pair in the presence of poly(ethylene glycol)diacrylate as a crosslinker. Surface morphology was characterized by the scanning electron microscopy technique. FT-IR analysis was used to identify the presence of different repeating units in the semi-interpenetrating polymer networks (semi-IPNs). Some swelling and diffusion characteristics were calculated for different semi-IPNs and hydrogels prepared under various formulations. The hydrogels were used in experiments on sorption of water-soluble cationic dye such as toluidine blue. Sorption of toluidine blue into the polymeric systems was studied by the batch sorption technique at 25 °C. Water uptake and dye sorption properties of the crosslinked polymeric systems were investigated as a function of chemical composition of the hydrogels.

  5. Polyacrylamide-Phytic Acid-Polydopamine Conducting Porous Hydrogel for Efficient Removal of Water-Soluble Dyes

    OpenAIRE

    Zhao, Zhen; Li, Leijiao; Geleta, Girma Selale; Ma, Lina; Wang, Zhenxin

    2017-01-01

    Removal of toxic dyes from wastewater has become a hot topic in both academic and industrial fields since there is growing concern about the threat of sewage to human health. Herein, we demonstrate that the three-dimensional porous polyacrylamide-phytic acid-polydopamine (termed as PAAM/PA/PDA) hydrogel can be served as reusable adsorbent with high efficiency for either anionic or cationic dyes. Using methyl blue (MB), methylene blue (YMB), methyl violet (MV) and neutral red (NR) as model dye...

  6. Removal of dyes from water using chitosan hydrogel/SiO2 and chitin hydrogel/SiO2 hybrid materials obtained by the sol-gel method.

    Science.gov (United States)

    Copello, Guillermo J; Mebert, Andrea M; Raineri, M; Pesenti, Mariela P; Diaz, Luis E

    2011-02-15

    This work describes the synthesis of chitosan hydrogel/SiO(2) and chitin hydrogel/SiO(2) hybrid mesoporous materials obtained by the sol-gel method for their use as biosorbents. Their adsorption capabilities against four dyes (Remazol Black B, Erythrosine B, Neutral Red and Gentian Violet) were compared in order to evaluate chitin as a plausible replacement for chitosan considering its efficiency and lower cost. Both chitin and chitosan were used in the form of hydrogels. This allowed full compatibility with the ethanol release from tetraethoxysilane. The hybrid materials were characterized by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Nitrogen Adsorption Isotherms and (13)C solid-state Nuclear Magnetic Resonance. Adsorption experimental data were analyzed using Langmuir, Freundlich and Dubinin-Radushkevich isotherm models along with the evaluation of adsorption energy and standard free energy (ΔG(0)). The adsorption was observed to be pH dependent. The main mechanism of dye adsorption was found to be a spontaneous charge associated interaction, except for EB adsorption on chitin/SiO(2) matrix, which showed to involve a lower energy physical adsorption interaction. Aside from highly charged dyes the chitin containing matrix has similar or higher adsorption capacity than the chitosan one.

  7. Reduced Graphene Oxide-Based Silver Nanoparticle-Containing Composite Hydrogel as Highly Efficient Dye Catalysts for Wastewater Treatment

    Science.gov (United States)

    Jiao, Tifeng; Guo, Haiying; Zhang, Qingrui; Peng, Qiuming; Tang, Yongfu; Yan, Xuehai; Li, Bingbing

    2015-07-01

    New reduced graphene oxide-based silver nanoparticle-containing composite hydrogels were successfully prepared in situ through the simultaneous reduction of GO and noble metal precursors within the GO gel matrix. The as-formed hydrogels are composed of a network structure of cross-linked nanosheets. The reported method is based on the in situ co-reduction of GO and silver acetate within the hydrogel matrix to form RGO-based composite gel. The stabilization of silver nanoparticles was also achieved simultaneously within the gel composite system. The as-formed silver nanoparticles were found to be homogeneously and uniformly dispersed on the surface of the RGO nanosheets within the composite gel. More importantly, this RGO-based silver nanoparticle-containing composite hydrogel matrix acts as a potential catalyst for removing organic dye pollutants from an aqueous environment. Interestingly, the as-prepared catalytic composite matrix structure can be conveniently separated from an aqueous environment after the reaction, suggesting the potentially large-scale applications of the reduced graphene oxide-based nanoparticle-containing composite hydrogels for organic dye removal and wastewater treatment.

  8. Multiple switching behaviors of poly(N-isopropylacrylamide) hydrogel with spironaphthoxazine and D-{pi}-A type dye

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun-Mi; Gwon, Seon-Yeong; Ji, Byung-Chul [Department of Advanced Organic Materials Science and Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); Wang Sheng, E-mail: wangsheng@zhjnc.edu.cn [School of Chemistry Science and Technology, Zhanjiang Normal University, Zhanjiang 524048 (China); Kim, Sung-Hoon, E-mail: shokim@knu.ac.kr [Department of Advanced Organic Materials Science and Engineering, Kyungpook National University, Daegu, 702-701 (Korea, Republic of); School of Chemistry Science and Technology, Zhanjiang Normal University, Zhanjiang 524048 (China)

    2012-03-15

    A multi-switchable poly(NIPAM-co-SPO-co-D-{pi}-A dye) hydrogel with a photochromic spironaphthoxazine and an electron donor-{pi}-conjugated-electron acceptor (D-{pi}-A) type dye was prepared by typical radical copolymerization. The low critical solution temperature (LCST) behavior was investigated by UV-vis spectroscopy, which allows the measurement of the phase transition from 20 to 40 Degree-Sign C in aqueous solution. The fluorescence intensity of the poly(NIPAM-co-SPO-co-D-{pi}-A dye) was temperature-dependent. Reversible modulation of fluorescence intensity was achieved using alternating irradiation with UV and visible light. Prepared polymer hydrogel also exhibited spectra change when not only used Cu{sup 2+} cation but also an acid unit. - Highlights: Black-Right-Pointing-Pointer A multi-switchable polymer was prepared by radical polymerization. Black-Right-Pointing-Pointer Fluorescence intensity of the polymer hydrogel was temperature-dependent. Black-Right-Pointing-Pointer Reversible modulation of fluorescence was achieved by irradiation with UV/vis. Black-Right-Pointing-Pointer Polymer hydrogel exhibited spectra change by Cu{sup 2+} cations as well as acid units.

  9. A facile one-step approach to functionalized graphene oxide-based hydrogels used as effective adsorbents toward anionic dyes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xinpeng; Liu, Zhiming [MOE Key Laboratory of Laser Life Science and SATCM Third Grade Laboratory of Chinese Medicine and Photonics Technology, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631 (China); Ye, Xiangping; Hu, Kun [National Testing Center for Optical Radiation Safety of Photoelectric Products, Huizhou, Guangdong 516003 (China); Zhong, Huiqing; Yu, Jianfeng; Jin, Mei [MOE Key Laboratory of Laser Life Science and SATCM Third Grade Laboratory of Chinese Medicine and Photonics Technology, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631 (China); Guo, Zhouyi, E-mail: ann@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and SATCM Third Grade Laboratory of Chinese Medicine and Photonics Technology, College of Biophotonics, South China Normal University, Guangzhou, Guangdong 510631 (China)

    2014-07-01

    Herein, we used a facile method mainly through self-assemble, hydrogen bonding and electrostatic interaction to synthesize poly(diallyldimethylammonium chloride)/graphene oxide (PDDA/GO) hydrogels, which can be easily used as adsorbents to eliminate anionic dyes. The as-prepared PDDA/GO hydrogels were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. In order to research the adsorption kinetics for the removal of anion dyes from water pollution, we further investigated that the effect of concentration, temperature, pH, ionic strength or cycle number on the removal process. The results indicated that due to the strong π–π stacking and anion–cation interaction, there were high removal efficiencies for both ponceau S (PS) and trypan blue (TB). The equilibrium time of adsorption is 30 min and 120 min for PS and TB, respectively, at which the solution could be decolorized to nearly colorless. Meanwhile, the adsorption process was more according with the pseudo-second-order model than the pseudo-first-order model. The hydrogels exhibited high removal efficiency for those two anionic dyes after four repeated adsorption and desorption treatments. It was demonstrated that PDDA/GO hydrogels would have great potential as a freestanding and reusable adsorbent for the practical application in water purification.

  10. Synthesis of Potato Starch-Acrylic-Acid Hydrogels by Gamma Radiation and Their Application in Dye Adsorption

    Directory of Open Access Journals (Sweden)

    Md. Murshed Bhuyan

    2016-01-01

    Full Text Available Several kinds of acrylic-acid-grafted-starch (starch/AAc hydrogels were prepared at room temperature (27°C by applying 5, 10, 15, 20, and 25 kGy of gamma radiation to 15% AAc aqueous solutions containing 5, 7.5, and 15% of starch. With increment of the radiation dose, gel fraction became higher and attained the maximum (96.5% at 15 kGy, above which the fraction got lowered. On the other hand, the gel fraction monotonically increased with the starch content. Swelling ratios were lower for the starch/AAc hydrogels prepared with higher gamma-ray doses and so with larger starch contents. Significant promotions of the swelling ratios were demonstrated by hydrolysis with NaOH: 13632±10% for 15 kGy radiation-dosed [5% starch/15% AAc] hydrogel, while the maximum swelling ratio was ~200% for those without the treatment. The authors further investigated the availability of the starch/AAc hydrogel as an adsorbent recovering dye waste from the industrial effluents by adopting methylene blue as a model material; the hydrogels showed high dye-capturing coefficients which increase with the starch ratio. The optimum dye adsorption was found to be 576 mg per g of the hydrogel having 7.5 starch and 15% AAc composition. Two kinetic models, (i pseudo-first-order and (ii pseudo-second-order kinetic models, were applied to test the experimental data. The latter provided the best correlation of the experimental data compared to the pseudo-first-order model.

  11. Novel stimuli responsive gellan gum-graft-poly(DMAEMA) hydrogel as adsorbent for anionic dye.

    Science.gov (United States)

    Karthika, J S; Vishalakshi, B

    2015-11-01

    In this study, gellan gum-grafted-poly((2-dimethylamino) ethyl methacrylate) (GG-g-poly(DMAEMA)) hydrogel was made by free radical polymerization in aqueous media employing microwave irradiation technique. Ammonium persulfate (APS)/N,N,N',N'-tetramethylethylenediamine (TMEDA) were used as initiator-accelerator pair. N,N'-methylenebisacrylamide (MBA) has been used as crosslinker. The gel was characterized by FTIR, XRD, TGA, DSC and SEM techniques. The characteristic peaks at 1724, 2630, 1147, 1650 and 1535cm(-1) in the IR spectrum confirms grafting and gel formation. The TGA data reveals that synthesized gels were thermally more stable than gellan gum. The XRD studies confirm the crystalline nature of the synthesized material. Swelling behaviour of the hydrogel under different temperatures and pH conditions was investigated. The results indicated drastic changes in swelling around pH 7.0 and 50°C. The gels were evaluated as an adsorbent to remove an anionic dye, methyl orange (MO), from aqueous solution. The pH conditions for maximum adsorption were optimized, the adsorption data is observed to fit best to the Freundlich isotherm model and the maximum adsorption capacity was found to be 25.8mgg(-1). The kinetic analysis revealed a second-order adsorption process. The thermodynamic parameters showed the adsorption to be exothermic and non-spontaneous at high temperatures.

  12. Selective Affinity Separation of Yeast Alcohol Dehydrogenase by Reverse Micelles with Unbound Triazine Dye

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The reversed micelles were formed with cationic cetyltrimethylammonium bromide (CTAB) as surfac tant and n-hexanol as cosolvent in the CTAB (50mmol.L-1)/hexanol (15% by volume)/hexane system. Cibacron Blue 3GA (CB) as an affinity ligand in the aqueous phase was directly introduced to the reversed micelles with electrostatic interaction between anionic CB and cationic surfactant. High molecular weight (Mr) protein, yeast alcohol dehydrogenase (YADH, Mr = 141000) from baker's yeast, has been purified using the affinity reversed micelles by the phase transfer method. Various parameters, such as CB concentration, pH and ionic strength, on YADH forward and backward transfer were studied. YADH can be transferred into and out from the reversed mi celles under mild conditions (only by regulation of solution pH and salt concentration) with the successful recovery of most YADH activity. Both forward and backward extractions occurred when the aqueous phase pH>pI with electrostatic attraction between YADH and CTAB. The recovery of YADH activity and purification factor have been improved with addition of a small amount of affinity CB. The recovery of YADH activity obtained was ~99% and the purification factor was about 4.0-fold after one cycle of full forward and backward extraction. The low ionic strength in the initial aqueous phase might be responsible for the YADH transfer into the reversed micellar phase.

  13. Polypeptide micelles with dual pH activatable dyes for sensing cells and cancer imaging.

    Science.gov (United States)

    Gong, Ping; Yang, Yueting; Yi, Huqiang; Fang, Shengtao; Zhang, Pengfei; Sheng, Zonghai; Gao, Guanhui; Gao, Duyang; Cai, Lintao

    2014-05-21

    pH is an important control parameter for maintenance of cell viability and tissue functions. pH monitoring provides valuable information on cell metabolic processes and the living environment. In this study, we prepared dual pH-sensitive, fluorescent dye-loaded polypeptide nanoparticles (DPNs) for ratiometric sensing of pH changes in living cells. DPNs contain two types of dyes: N-(rhodamine B) lactam cystamine (RBLC), an acid activatable fluorescent dye with increased fluorescence in an acidic environment, and fluorescein isothiocyanate (FITC), a base activatable fluorescent dye with enhanced fluorescence in an alkaline environment. Hence, DPNs exhibited a dual response signal with strong red fluorescence and weak green fluorescence under acidic conditions; in contrast, they showed strong green fluorescence and almost no red fluorescence under alkaline and neutral conditions. The favorable inverse pH responses of the two fluorescent dyes resulted in ratiometric pH determination for DPNs with an optimized pH-sensitive range of pH 4.5-7.5. Quantitative analysis of the intracellular pH of intact MCF-7 cells has been successfully demonstrated with our nanosensor. Moreover, single acid activatable fluorescent dye doped polypeptide nanoparticles that only contained RBLC can distinguish tumor tissue from normal tissue by monitoring the acidic extracellular environment.

  14. Effective removal of cationic dyes from aqueous solution using gum ghatti-based biodegradable hydrogel

    CSIR Research Space (South Africa)

    Mittal, H

    2015-08-01

    Full Text Available Biodegradable hydrogels of gum ghatti (Gg) with a co-polymer mixture of acrylamide (AAm) and methacrylic acid (MAA) (termed as Gg-cl-P(AAm-co-MAA)) were synthesised by microwave-assisted free radical graft co-polymerisation technique. The hydrogel...

  15. Dynamic and spectroscopic studies of nano-micelles comprising dye in water/ dioctyl sodium sulfosuccinate /decane droplet microemulsion at constant water content

    Science.gov (United States)

    Rahdar, Abbas; Almasi-Kashi, Mohammad

    2017-01-01

    In the present work, the dynamic and spectroscopic properties of water-in-decane dioctyl sodium sulfosuccinate (AOT) microemulsions comprising dye, Rhodamine B (RB), were studied by varying content of decane at the constant water content (W = 20), by using dynamic light scattering (DLS), UV/visible, and fluorescence techniques. The characterization results of DLS of AOT micelles showed that by decreasing concentration of Rhodamine B in the water/AOT/decane microemulsion, the inter-droplet interactions changed from attractive to repulsive as the mass fraction of nano-droplets (MFD) increased. A deviation in the absorption spectra of Rhodamine B from the Beer's law at the high Rhodamine B concentration (0.001) was observed in the AOT reversed micelles. The Quenching in the emission intensity of AOT droplets comprising Rhodamine B and red shift in λmax of fluorescence of dye was observed as a function of concentration of RB in AOT RMs. The Stokes shift of AOT droplets containing the high concentration of RB, increased with mass fraction of nano-droplet (MFD), whereas at the low Rhodamine B concentration, its variation remained constant up to MFD = 0.07, and then increased.

  16. Gum karaya based hydrogel nanocomposites for the effective removal of cationic dyes from aqueous solutions

    CSIR Research Space (South Africa)

    Mittala, H

    2016-02-01

    Full Text Available after nanocomposite formation with SiC NPs. The HNC was employed for the removal of cationic dyes, i.e., malachite green (MG) and rhodamine B (RhB) from the aqueous solution. The HNC was found to remove 91% (MG) and 86% (RhB) of dyes with a polymer dose...

  17. Removal of dyes from water using chitosan hydrogel/SiO{sub 2} and chitin hydrogel/SiO{sub 2} hybrid materials obtained by the sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Copello, Guillermo J. [Catedra de Quimica Analitica Instrumental, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (UBA), Junin 956, C1113AAD Buenos Aires (Argentina); IQUIMEFA (UBA-CONICET), Junin 956, C1113AAD Buenos Aires (Argentina); Mebert, Andrea M.; Raineri, M.; Pesenti, Mariela P. [Catedra de Quimica Analitica Instrumental, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (UBA), Junin 956, C1113AAD Buenos Aires (Argentina); Diaz, Luis E., E-mail: ldiaz@ffyb.uba.ar [Catedra de Quimica Analitica Instrumental, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (UBA), Junin 956, C1113AAD Buenos Aires (Argentina); IQUIMEFA (UBA-CONICET), Junin 956, C1113AAD Buenos Aires (Argentina)

    2011-02-15

    This work describes the synthesis of chitosan hydrogel/SiO{sub 2} and chitin hydrogel/SiO{sub 2} hybrid mesoporous materials obtained by the sol-gel method for their use as biosorbents. Their adsorption capabilities against four dyes (Remazol Black B, Erythrosine B, Neutral Red and Gentian Violet) were compared in order to evaluate chitin as a plausible replacement for chitosan considering its efficiency and lower cost. Both chitin and chitosan were used in the form of hydrogels. This allowed full compatibility with the ethanol release from tetraethoxysilane. The hybrid materials were characterized by Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Nitrogen Adsorption Isotherms and {sup 13}C solid-state Nuclear Magnetic Resonance. Adsorption experimental data were analyzed using Langmuir, Freundlich and Dubinin-Radushkevich isotherm models along with the evaluation of adsorption energy and standard free energy ({Delta}G{sup 0}). The adsorption was observed to be pH dependent. The main mechanism of dye adsorption was found to be a spontaneous charge associated interaction, except for EB adsorption on chitin/SiO{sub 2} matrix, which showed to involve a lower energy physical adsorption interaction. Aside from highly charged dyes the chitin containing matrix has similar or higher adsorption capacity than the chitosan one.

  18. pH-induced vesicle-to-micelle transition in amphiphilic diblock copolymer: investigation by energy transfer between in situ formed polymer embedded gold nanoparticles and fluorescent dye.

    Science.gov (United States)

    Maiti, Chiranjit; Banerjee, Rakesh; Maiti, Saikat; Dhara, Dibakar

    2015-01-01

    The ability to regulate the formation of nanostructures through self-assembly of amphiphilic block copolymers is of immense significance in the field of biology and medicine. In this work, a new block copolymer synthesized by using reversible addition-fragmentation chain transfer (RAFT) polymerization technique from poly(ethylene glycol) monomethyl ether acrylate (PEGMA) and Boc-l-tryptophan acryloyloxyethyl ester (Boc-l-trp-HEA) was found to spontaneously form pH-responsive water-soluble nanostructures after removal of the Boc group. While polymer vesicles or polymerosomes were formed at physiological pH, the micelles were formed at acidic pH (transition. Formation of these nanostructures was confirmed by different characterization techniques, viz. transmission electron microscopy, dynamic light scattering, and steady-state fluorescence measurements. Further, these vesicles were successfully utilized to reduce HAuCl4 and stabilize the resulting gold nanoparticles (AuNPs). These AuNPs, confined within the hydrophobic shell of the vesicles, could participate in energy transfer process with fluorescent dye molecules encapsulated in the core of the vesicles, thus forming a nanometal surface energy transfer (NSET) pair. Subsequently, following the efficiency of energy transfer between this pair, it was possible to monitor the process of transition from vesicles to micelles. Thus, in this work, we have successfully demonstrated that NSET can be used to follow the transition between nanostructures formed by amphiphilic block copolymers.

  19. Poly (Acrylamide-co-Acrylic Acid) Hydrogel Induced by Glow-Discharge Electrolysis Plasma and Its Adsorption Properties for Cationic Dyes

    Science.gov (United States)

    Yu, Jie; Yang, Gege; Pan, Yuanpei; Lu, Quanfang; Yang, Wu; Gao, Jinzhang

    2014-08-01

    In this paper, poly (acrylamide-co-acrylic acid) (P(AM-co-AA)) hydrogel was prepared in an aqueous solution by using glow-discharge electrolysis plasma (GDEP) induced copolymerization of acrylamide (AM) and acrylic acid (AA), in which N,N'-methylenebisacrylamide (MBA) was used as a crosslinker. A mechanism for the synthesis of P(AM-co-AA) hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail: the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P(AM-co-AA) hydrogel exhibits a very high adsorption potential and the experimental adsorption capacities for Crystal violet (CV) and Methylene blue (MB) were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P(AM-co-AA) hydrogel for cationic dyes was also discussed.

  20. Role of N-vinyl-2-pyrrolidinone on the thermoresponsive behavior of PNIPAm hydrogel and its release kinetics using dye and vitamin-B12 as model drug.

    Science.gov (United States)

    Maheswari, B; Babu, P E Jagadeesh; Agarwal, Mayank

    2014-01-01

    Temperature-sensitive hydrogels hold great promise in biological applications as they can respond to changes in physiological temperature to produce a desired effect like controlled drug delivery. In this study, a series of poly(N-isopropylacrylamide-co-N-vinyl-2-pyrrolidinone) thermosensitive hydrogels were synthesized by radical copolymerization of NIPAm with 1-vinyl-2-pyrrolidinone (NVP). By altering the initial NIPAm/NVP mole ratios, copolymers were synthesized to have their own distinctive lower critical solution temperature which was established using differential scanning calorimetry. The swelling behavior of the hydrogel was analyzed gravimetrically and it was observed that reswelling rate increases with increasing NVP mole ratio. Further characterizations of the hydrogels were performed using Fourier transform infrared spectroscopy and scanning electron microscopy. Release kinetics with respect to temperature was studied using methylene blue dye solution and vitamin B12. Kinetic modeling of the release profile revealed that the release mechanism is a non-Fickian diffusion mechanism. These results suggested that this material has potential application as intelligent drug carriers. The quantities of residual monomers in the PIV4 hydrogel were determined by HPLC method, and the results show almost complete conversion.

  1. TiO2 film decorated with highly dispersed polyoxometalate nanoparticles synthesized by micelle directed method for the efficiency enhancement of dye-sensitized solar cells

    Science.gov (United States)

    He, Lifei; Chen, Li; Zhao, Yue; Chen, Weilin; Shan, Chunhui; Su, Zhongmin; Wang, Enbo

    2016-10-01

    In this work, two kinds of polyoxometalate (POM) nanoparticles with controlled shapes and structures were synthesized by micelle directed method and then composited with TiO2 via calcination to remove the surfactants owing to the excellent electronic storage and transmission ability of POM, finally obtaining two kinds of TiO2 composites with highly dispersed and small-sized POM nanoparticles (∼1 nm). The TiO2 composites were then induced into the photoanodes of dye-sensitized (N719) solar cells (DSSCs). The separation of electron-holes becomes more favorable due to the nanostructure and high dispersion of POM which provide more active sites than pure POM tending to agglomeration. The TiO2 composite photoanodes finally yielded the power conversion efficiency (PCE) of 8.4% and 8.2%, respectively, which were 42% and 39% higher than the pristine TiO2 based anodes. In addition, the mechanisms of POM in DSSC are proposed.

  2. Fabrication of starch-graft-poly(acrylamide)/graphene oxide/hydroxyapatite nanocomposite hydrogel adsorbent for removal of malachite green dye from aqueous solution.

    Science.gov (United States)

    Hosseinzadeh, Hossein; Ramin, Sonia

    2017-08-01

    This article reports the efficient removal of malachite green (MG) dye from aqueous solution using a novel polysaccharide-based nanocomposite hydrogel adsorbent (NHA). The NHAs of different compositions were prepared through a simple free radical graft copolymerization of acrylamide (AM) monomer onto starch backbones in the presence of graphene oxide (GO) nano sheets and nono-hydroxyapatite (n-HAp). The surface morphology and chemical properties of the prepared NHAs were fully examined by using FTIR, SEM, TEM, XRD and TGA. The biocompatibility, biodegradability, porosity, water content and water uptake of the synthesized NHAs were also evaluated. The NHA was employed as bioadsorbents for the adsorption of MG dye. The temperature dependence data also revealed that MG sorption process was feasible, spontaneous and endothermic. The MG adsorption rates were described by the pseudo-second-order model. Furthermore, the adsorption isotherm data fitted well with the Langmuir isotherm model with a maximum adsorption capacity of 297mgg(-1) for MG dye. The NHA also showed an excellent regeneration capacity after five consecutive cycles of dye adsorption-desorption. According to the results, the prepared NHAs could be environment friendly and promising adsorbents for the adsorption of different cationic dyes from contaminated water. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Micelles Hydrodynamics

    CERN Document Server

    Svintradze, David V

    2016-01-01

    A micelle consists of monolayer of lipid molecules containing hydrophilic head and hydrophobic tail. These amphiphilic molecules in aqueous environment aggregate spontaneously into monomolecular layer held together due to hydrophobic effect by weak non-covalent forces. Micelles are flexible surfaces that show variety of shapes of different topology, but remarkably in mechanical equilibrium conditions they are spherical in shape. The shape and size of a micelle are functions of many variables such as lipid concentration, temperature, ionic strength, etc. Addressing the question, why the shape of micelles is sphere in mechanical equilibrium conditions, analytically proved to be a difficult problem. In the following paper we offer the shortest and elegant analytical proof of micelles spheroidal nature when they are thermodynamically equilibrated with solvent. The formalism presented in this paper can be readily extended to any homogenous surfaces, such are vesicles and membranes.

  4. Studies on the PEO-PPO-PEO Block Copolymer Release from Alginate Hydrogel

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Introduction Alginate hydrogel is one of the most widely used carriers for the immobilization of micro bial cells. If surfactants are encapsulated with alginate hydrogel, increasing temperature or concentration can make the encapsulated surfactants aggregate and form micelle.

  5. Synthesis and characterization of acrylamide/acrylic acid hydrogel and its application for crystal violet dye adsorption

    Directory of Open Access Journals (Sweden)

    Chaisuksan, Y.

    2006-03-01

    Full Text Available Acrylamide/acrylic acid (AAm/AAc hydrogel was prepared by free radical polymerization in aqueous solution of acrylamide and acrylic acid as a comonomer using ammonium persulfate and N,N,N’,N’-tetramethylethylenediamine as an initiator system and N,N’-methylenebisacrylamide as a crosslinker at room temperature. The hydrogels were prepared from acrylamide/acrylic acid with the ratios of 2.5/97.5, 5/95, 10/90, 20/80, 30/70, 40/60 and 50/50. The swelling property and the equilibrium water content of the hydrogel were determined in distilled water and in a solution of pH 3, 5, 7 and 8 for 96 hours. The result showed that the maximum swelling and equilibrium water content of the hydrogel obtaining from AAm/ AAc in the ratio of 10/90 were found to be 3,945% and 0.9747 at pH 8, respectively. The adsorption capacity of AAm/AAc (10/90 for crystal violet was also investigated at pH 3, 5, 7, 8 and 9 for 48 hours. It was found that the optimum adsorption capacity of the hydrogel was in the range of 5-8. The adsorption rate was 90% of the sorption completion within 48 hours. The equilibrium data fitted well to the Langmuir isotherm with the maximum adsorption capacity of 116.28 mg/g at pH 7.

  6. Nano-hydrogels of methoxy polyethylene glycol-grafted branched polyethyleneimine via biodegradable cross-linking of Zn2+-ionomer micelle template

    Science.gov (United States)

    Abolmaali, Samira Sadat; Tamaddon, Ali Mohammad; Dinarvand, Rasoul

    2013-12-01

    Soft polymeric nanomaterials were synthesized by the template-assisted method involving self-association of methoxy polyethylene glycol- g-branched polyethyleneimine (mPEG- g-branched PEI) ionomer by transition metal ions such as Zn2+ followed by chemical cross-linking of the polyamine core by dithiopropionic acid. The formation of donor-acceptor complexes of Zn2+ and PEI ionomer was characterized by FT-IR spectroscopy and potentiometric titration. Turbidimetry was performed to study the solution property of the complexes which depended on pH, relative weight fraction of mPEG, and the molar ratio of Zn2+. The cross-linking reaction was studied by TNBS assay, 1H-NMR, and size exclusion chromatography. Upon removal of Zn2+ from cl-mPEG- g-branched PEI/Zn2+ at pH 3 by dialysis, the resulting cross-linked self-assembly represented a uniform, stable, and less positively charged hydrogel-like nanosphere with an intensity-averaged size ranging from 150 to 250 nm as determined by a Zetasizer. Atomic forced microscopy imaging was performed in intermittent contact mode in air that revealed discrete and oval-to-spherically shaped particles with average sizes ranging from 40 to 50 nm depending on the degree of cross-linking. This functional nanocarrier is expected to exhibit some key features such as active encapsulation of negatively charged hydrophilic agents in the swollen core of polyamine network and a hydrophilic mPEG shell which provides an increased solubility and passive targeting of active pharmaceutical agents to impaired tissues. The nano-hydrogels especially at 12 % degrees of cross-link demonstrated excellent biocompatibility determined by different experiments such as albumin aggregation, erythrocyte aggregation, hemolysis, and MTT cytotoxicity assay. Moreover, biodegradability of the cross-links as shown by the Ellman assay can offer a time-dependent degradation and redox-stimulated release of active agents.

  7. Magainin II modified polydiacetylene micelles for cancer therapy

    Science.gov (United States)

    Yang, Danling; Zou, Rongfeng; Zhu, Yu; Liu, Ben; Yao, Defan; Jiang, Juanjuan; Wu, Junchen; Tian, He

    2014-11-01

    Polydiacetylene (PDA) micelles have been widely used to deliver anticancer drugs in the treatment of a variety of tumours and for imaging living cells. In this study, we developed an effective strategy to directly conjugate magainin II (MGN-II) to the surface of PDA micelles using a fluorescent dye. These stable and well-defined PDA micelles had high cytotoxicity in cancer cell lines, and were able to reduce the tumour size in mice. The modified PDA micelles improved the anticancer effects of MGN-II in the A549 cell line only at a concentration of 16.0 μg mL-1 (IC50). In addition, following irradiation with UV light at 254 nm, the PDA micelles gave rise to an energy transfer from the fluorescent dye to the backbone of PDA micelles to enhance the imaging of living cells. Our results demonstrate that modified PDA micelles can not only be used in the treatment of tumors in vitro and in vivo in a simple and directed way, but also offer a new platform for designing functional liposomes to act as anticancer agents.Polydiacetylene (PDA) micelles have been widely used to deliver anticancer drugs in the treatment of a variety of tumours and for imaging living cells. In this study, we developed an effective strategy to directly conjugate magainin II (MGN-II) to the surface of PDA micelles using a fluorescent dye. These stable and well-defined PDA micelles had high cytotoxicity in cancer cell lines, and were able to reduce the tumour size in mice. The modified PDA micelles improved the anticancer effects of MGN-II in the A549 cell line only at a concentration of 16.0 μg mL-1 (IC50). In addition, following irradiation with UV light at 254 nm, the PDA micelles gave rise to an energy transfer from the fluorescent dye to the backbone of PDA micelles to enhance the imaging of living cells. Our results demonstrate that modified PDA micelles can not only be used in the treatment of tumors in vitro and in vivo in a simple and directed way, but also offer a new platform for

  8. Sucrose monoester micelles size determined by Fluorescence Correlation Spectroscopy (FCS.

    Directory of Open Access Journals (Sweden)

    Susana A Sanchez

    Full Text Available One of the several uses of sucrose detergents, as well as other micelle forming detergents, is the solubilization of different membrane proteins. Accurate knowledge of the micelle properties, including size and shape, are needed to optimize the surfactant conditions for protein purification and membrane characterization. We synthesized sucrose esters having different numbers of methylene subunits on the substituent to correlate the number of methylene groups with the size of the corresponding micelles. We used Fluorescence Correlation Spectroscopy (FCS and two photon excitation to determine the translational D of the micelles and calculate their corresponding hydrodynamic radius, R(h. As a fluorescent probe we used LAURDAN (6-dodecanoyl-2-dimethylaminonaphthalene, a dye highly fluorescent when integrated in the micelle and non-fluorescent in aqueous media. We found a linear correlation between the size of the tail and the hydrodynamic radius of the micelle for the series of detergents measured.

  9. Micelle-Directing Synthesis of Ag-Doped WO3 and MoO3 Composites for Photocatalytic Water Oxidation and Organic-Dye Adsorption.

    Science.gov (United States)

    Bate, Nasen; Shi, Hongfei; Chen, Li; Wang, Jiabo; Xu, Shasha; Chen, Weilin; Li, Jianping; Wang, Enbo

    2017-07-20

    In this paper, an Ag-doped WO3 (and MoO3 ) composite has been prepared by following a simple micelle-directed method and high-temperature sintering route. The as-prepared samples were characterized by X-ray diffraction, inductively coupled plasma, transmission electron microscopy, X-ray photoelectron spectroscopy, UV/Vis diffuse reflectance spectroscopy, Brunauer-Emmett-Teller, photoluminescence spectroscopy, and electrochemical impedance spectroscopy techniques. The photocatalytic experiments reveal that their oxygen-production rates are up to 95.43 μmol (75.45 μmol) for Ag-doped WO3 (MoO3 ), which is 9.5 (7.3) times higher than that of pure WO3 : 9.012 μmol (MoO3 : 9.00 μmol) under visible-light illumination (λ≥420 nm), respectively. The improvement of their photocatalytic activity is attributed to the enhancement of their visible-light absorption and the separation efficiency of photogenerated carriers by Ag doping. Moreover, Ag-doped WO3 (MoO3 ) also shows excellent adsorption of rhodamine B (RhB) and methylene blue (MB) in aqueous solution, with maximum adsorption capacities towards RhB and MB of 822 and 820 mg g(-1) for Ag-doped WO3 , and 642 and 805 mg g(-1) for Ag-doped MoO3 , respectively. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Structure and Conductivity of Semiconducting Polymer Hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Rachel C.; Ferreira, Amy S.; Aguirre, Jordan C.; Kilbride, Daniel; Toso, Daniel B.; Mayoral, Kenny; Zhou, Z. Hong; Kopidakis, Nikos; Rubin, Yves; Schwartz, Benjamin J.; Mason, Thomas G.; Tolbert, Sarah H.

    2016-07-07

    Poly(fluorene-alt-thiophene) (PFT) is a conjugated polyelectrolyte that self-assembles into rod-like micelles in water, with the conjugated polymer backbone running along the length of the micelle. At modest concentrations (-10 mg/mL in aqueous solutions), PFT forms hydrogels, and this work focuses on understanding the structure and intermolecular interactions in those gel networks. The network structure can be directly visualized using cryo electron microscopy. Oscillatory rheology studies further tell us about connectivity within the gel network, and the data are consistent with a picture where polymer chains bridge between micelles to hold the network together. Addition of tetrahydrofuran (THF) to the gels breaks those connections, but once the THF is removed, the gel becomes stronger than it was before, presumably due to the creation of a more interconnected nanoscale architecture. Small polymer oligomers can also passivate the bridging polymer chains, breaking connections between micelles and dramatically weakening the hydrogel network. Fits to solution-phase small-angle X-ray scattering data using a Dammin bead model support the hypothesis of a bridging connection between PFT micelles, even in dilute aqueous solutions. Finally, time-resolved microwave conductivity measurements on dried samples show an increase in carrier mobility after THF annealing of the PFT gel, likely due to increased connectivity within the polymer network.

  11. Solubilization of Hydrophobic Dyes in Surfactant Solutions

    Directory of Open Access Journals (Sweden)

    Ali Reza Tehrani-Bagha

    2013-02-01

    Full Text Available In this paper, the use of surfactants for solubilization of hydrophobic organic dyes (mainly solvent and disperse dyes has been reviewed. The effect of parameters such as the chemical structures of the surfactant and the dye, addition of salt and of polyelectrolytes, pH, and temperature on dye solubilization has been discussed. Surfactant self-assemble into micelles in aqueous solution and below the concentration where this occurs—the critical micelle concentration (CMC—there is no solubilization. Above the CMC, the amount of solubilized dye increases linearly with the increase in surfactant concentration. It is demonstrated that different surfactants work best for different dyes. In general, nonionic surfactants have higher solubilization power than anionic and cationic surfactants. It is likely that the reason for the good performance of nonionic surfactants is that they allow dyes to be accommodated not only in the inner, hydrocarbon part of the micelle but also in the headgroup shell. It is demonstrated that the location of a dye in a surfactant micelle can be assessed from the absorption spectrum of the dye-containing micellar solution.

  12. Hydrogel based occlusion systems

    OpenAIRE

    Stam, F.A.; Jackson, N.; Dubruel, P.; Adesanya, K.; Embrechts, A; Mendes, E.; Neves, H.P.; Herijgers, P; Verbrugghe, Y.; Shacham, Y.; Engel, L.; Krylov, V

    2013-01-01

    A hydrogel based occlusion system, a method for occluding vessels, appendages or aneurysms, and a method for hydrogel synthesis are disclosed. The hydrogel based occlusion system includes a hydrogel having a shrunken and a swollen state and a delivery tool configured to deliver the hydrogel to a target occlusion location. The hydrogel is configured to permanently occlude the target occlusion location in the swollen state. The hydrogel may be an electro-activated hydrogel (EAH) which could be ...

  13. Complex coacervate core micelles.

    Science.gov (United States)

    Voets, Ilja K; de Keizer, Arie; Cohen Stuart, Martien A

    2009-01-01

    In this review we present an overview of the literature on the co-assembly of neutral-ionic block, graft, and random copolymers with oppositely charged species in aqueous solution. Oppositely charged species include synthetic (co)polymers of various architectures, biopolymers - such as proteins, enzymes and DNA - multivalent ions, metallic nanoparticles, low molecular weight surfactants, polyelectrolyte block copolymer micelles, metallo-supramolecular polymers, equilibrium polymers, etcetera. The resultant structures are termed complex coacervate core/polyion complex/block ionomer complex/interpolyelectrolyte complex micelles (or vesicles); i.e., in short C3Ms (or C3Vs) and PIC, BIC or IPEC micelles (and vesicles). Formation, structure, dynamics, properties, and function will be discussed. We focus on experimental work; theory and modelling will not be discussed. Recent developments in applications and micelles with heterogeneous coronas are emphasized.

  14. CHARMM-GUI micelle builder for pure/mixed micelle and protein/micelle complex systems.

    Science.gov (United States)

    Cheng, Xi; Jo, Sunhwan; Lee, Hui Sun; Klauda, Jeffery B; Im, Wonpil

    2013-08-26

    Micelle Builder in CHARMM-GUI, http://www.charmm-gui.org/input/micelle , is a web-based graphical user interface to build pure/mixed micelle and protein/micelle complex systems for molecular dynamics (MD) simulation. The robustness of Micelle Builder is tested by simulating four detergent-only homogeneous micelles of DHPC (dihexanoylphosphatidylcholine), DPC (dodecylphosphocholine), TPC (tetradecylphosphocholine), and SDS (sodium dodecyl sulfate) and comparing the calculated micelle properties with experiments and previous simulations. As a representative protein/micelle model, Pf1 coat protein is modeled and simulated in DHPC micelles with three different numbers of DHPC molecules. While the number of DHPC molecules in direct contact with Pf1 protein converges during the simulation, distinct behavior and geometry of micelles lead to different protein conformations in comparison to that in bilayers. It is our hope that CHARMM-GUI Micelle Builder can be used for simulation studies of various protein/micelle systems to better understand the protein structure and dynamics in micelles as well as distribution of detergents and their dynamics around proteins.

  15. PRAGMATIC HYDROGELS

    Directory of Open Access Journals (Sweden)

    Patil S.A.

    2011-03-01

    Full Text Available Man has always been plagued with many ailments and diseases. The field of pharmaceutical science has today become more invaluable in helping to keep us healthy and prevent disease. The availability of large molecular weight protein and peptide-based drugs due to the recent advances has given us a new ways to treat a number of diseases. I wish to present new and promising techniques for the production of drug and protein delivery formulations that have been developed that is Hydrogel. These are presently under investigation as a delivery system for bioactive molecules as having similar physical properties as that of living tissue, which is due to their high water content, soft and rubbery consistency and low interfacial tension with water and biological fluids. Hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids. The networks are composed of homopolymers or copolymers, and are insoluble due to the presence of chemical crosslink (tie-points, junctions or physical crosslink, such as entanglements or crystallite. The latter provide the network structure and physical integrity. These hydrogels exhibit a thermodynamic compatibility with water which allows them to swell in aqueous media. The nature of the degradation product can be tailored by a rational and proper selection of building blocks. The soft and rubbery nature of hydrogels minimizes irritation to surrounding tissues. In general, hydrogels possess good biocompatibility and biodegradability.

  16. Hydrogel based occlusion systems

    NARCIS (Netherlands)

    Stam, F.A.; Jackson, N.; Dubruel, P.; Adesanya, K.; Embrechts, A.; Mendes, E.; Neves, H.P.; Herijgers, P.; Verbrugghe, Y.; Shacham, Y.; Engel, L.; Krylov, V.

    2013-01-01

    A hydrogel based occlusion system, a method for occluding vessels, appendages or aneurysms, and a method for hydrogel synthesis are disclosed. The hydrogel based occlusion system includes a hydrogel having a shrunken and a swollen state and a delivery tool configured to deliver the hydrogel to a tar

  17. Bioresponsive hydrogels

    Directory of Open Access Journals (Sweden)

    Rein V. Ulijn

    2007-04-01

    Full Text Available We highlight recent developments in hydrogel materials with biological responsiveness built in. These ‘smart’ biomaterials change properties in response to selective biological recognition events. When exposed to a biological target (nutrient, growth factor, receptor, antibody, enzyme, or whole cell, molecular recognition events trigger changes in molecular interactions that translate into macroscopic responses, such as swelling/collapse or solution-to-gel transitions. The hydrogel transitions may be used directly as optical readouts for biosensing, linked to the release of actives for drug delivery, or instigate biochemical signaling events that control or direct cellular behavior. Accordingly, bioresponsive hydrogels have gained significant interest for application in diagnostics, drug delivery, and tissue regeneration/wound healing.

  18. Smart hydrogel functional materials

    CERN Document Server

    Chu, Liang-Yin; Ju, Xiao-Jie

    2014-01-01

    This book systematically introduces smart hydrogel functional materials with the configurations ranging from hydrogels to microgels. It serves as an excellent reference for designing and fabricating artificial smart hydrogel functional materials.

  19. Control of β-carotene bioaccessibility using starch-based filled hydrogels.

    Science.gov (United States)

    Mun, Saehun; Kim, Yong-Ro; McClements, David Julian

    2015-04-15

    β-Carotene was incorporated into three types of delivery system: (i) "emulsions": protein-coated fat droplets dispersed in water; (ii) "hydrogels": rice starch gels; and (iii) "filled hydrogels": protein-coated fat droplets dispersed in rice starch gels. Fat droplets in filled hydrogels were stable in simulated mouth and stomach conditions, but aggregated under small intestinal conditions. Fat droplets in emulsions aggregated under oral, gastric, and intestinal conditions. β-Carotene bioaccessibility was higher when encapsulated in filled hydrogels than in emulsions or hydrogels, which was attributed to increased aggregation stability of the fat droplets leading to a larger exposed lipid surface area. β-Carotene bioaccessibility in starch hydrogels containing no fat was very low (≈1%) due to its crystalline nature and lack of mixed micelles to solubilise it. The information presented may be useful for the design of rice-starch based gel products fortified with lipophilic nutraceuticals.

  20. A novel temperature-responsive micelle for enhancing combination therapy

    Directory of Open Access Journals (Sweden)

    Peng CL

    2016-07-01

    Full Text Available Cheng-Liang Peng,1,* Yuan-I Chen,2,3,* Hung-Jen Liu,2 Pei-Chi Lee,2 Tsai-Yueh Luo,1 Ming-Jium Shieh2,3 1Isotope Application Division, Institute of Nuclear Energy Research, Taoyuan, 2Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, Taipei, 3Department of Oncology, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan *These authors contributed equally to this work Abstract: A novel thermosensitive polymer p(N-isopropylacrylamide-co-poly[ethylene glycol] methyl ether acrylate-block-poly(epsilon-caprolactone, p(NIPAAM-co-PEGMEA-b-PCL, was synthesized and developed as nanomicelles. The hydrophobic heat shock protein 90 inhibitor 17-allylamino-17-demethoxygeldanamycin and the photosensitizer cyanine dye infrared-780 were loaded into the core of the micelles to achieve both chemotherapy and photothermal therapy simultaneously at the tumor site. The release of the drug could be controlled by varying the temperature due to the thermosensitive nature of the micelles. The micelles were less than 200 nm in size, and the drug encapsulation efficiency was >50%. The critical micelle concentrations were small enough to allow micelle stability upon dilution. Data from cell viability and animal experiments indicate that this combination treatment using photothermal therapy with chemotherapy had synergistic effects while decreasing side effects. Keywords: thermosensitive, photothermal therapy, chemotherapy, nanocarrier, control release, synergistic effect

  1. Polymerization of anionic wormlike micelles.

    Science.gov (United States)

    Zhu, Zhiyuan; González, Yamaira I; Xu, Hangxun; Kaler, Eric W; Liu, Shiyong

    2006-01-31

    Polymerizable anionic wormlike micelles are obtained upon mixing the hydrotropic salt p-toluidine hydrochloride (PTHC) with the reactive anionic surfactant sodium 4-(8-methacryloyloxyoctyl)oxybenzene sulfonate (MOBS). Polymerization captures the cross-sectional radius of the micelles (approximately 2 nm), induces micellar growth, and leads to the formation of a stable single-phase dispersion of wormlike micellar polymers. The unpolymerized and polymerized micelles were characterized using static and dynamic laser light scattering, small-angle neutron scattering, 1H NMR, and stopped-flow light scattering. Stopped-flow light scattering was also used to measure the average lifetime of the unpolymerized wormlike micelles. A comparison of the average lifetime of unpolymerized wormlike micelles with the surfactant monomer propagation rate was used to elucidate the mechanism of polymerization. There is a significant correlation between the ratio of the average lifetime to the monomer propagation rate and the average aggregation number of the polymerized wormlike micelles.

  2. Synthesis and Characterization of Porous Hydrogel Based on Lignin and Polyacrylamide

    Directory of Open Access Journals (Sweden)

    Qinghua Feng

    2014-06-01

    Full Text Available A porous lignin-containing hydrogel was developed for dye removal via graft copolymerization of acetic acid lignin (AAL and acrylamide (AAm, in the presence of ethyleneglycol dimethacrylate (EGDMA as a crosslinker and H2O2 as an initiator. AAL was characterized by FT-IR and TGA. After being washed to remove impurities, the hydrogel was characterized by FT-IR, TGA, SEM, and swelling ratio. FT-IR spectra suggested that AAL was present in the hydrogel. The TGA curves revealed that the introduction of AAL had no significant impact on the thermal stability of PAAm. SEM images showed that the honeycomb-like structure of the hydrogel was improved with increasing AAL content. The swelling ratio data showed that the hydrogel with a high AAL/AAm ratio was sensitive to pH. Furthermore, increased lignin content of the hydrogel favors the dye adsorption.

  3. Enzymatic reactions in reversed micelles

    NARCIS (Netherlands)

    Hilhorst, M.H.

    1984-01-01

    It has been recognised that enzymes in reversed micelles have potential for application in chemical synthesis. Before these expectations will be realised many problems must be overcome. This thesis deals with some of them.In Chapter 1 the present knowledge about reversed micelles and micellar enzymo

  4. Enzyme recovery using reversed micelles.

    NARCIS (Netherlands)

    Dekker, M.

    1990-01-01

    The objective of this study was to develop a liquid-liquid extraction process for the recovery of extracellular enzymes. The potentials of reaching this goal by using reversed micelles in an organic solvent have been investigated.Reversed micelles are aggregates of surfactant molecules containing an

  5. Nano-hydroxyapatite/polyacrylamide composite hydrogels with high mechanical strengths and cell adhesion properties.

    Science.gov (United States)

    Li, Zhiyong; Mi, Wenying; Wang, Huiliang; Su, Yunlan; He, Changcheng

    2014-11-01

    Nano-hydroxyapatite/polyacrylamide composite hydrogels were successfully fabricated by physically mixing nano-hydroxyapatite (nHAp) particles into a peroxidized micelles initiated and cross-linked (pMIC) polyacrylamide (PAAm) hydrogel. The nanocomposite hydrogels exhibited excellent mechanical properties. The fracture tensile stresses of the gels were in the range of 0.21-0.86 MPa and the fracture tensile strains were up to 30 mm/mm, and the compressive strengths were up to 35.8 MPa. Meanwhile the introduction of nHAp endowed the composite hydrogels with good cell adhesion properties. This nHAp/PAAm nanocomposite hydrogel is expected to find potential applications in tissue engineering.

  6. Fluorescence decay of singlet excited-state of safranine T and its interaction with ground-state of pyridinthiones in micelles and homogeneous media.

    Science.gov (United States)

    El-Kemar, Maged A; Khedr, Rehab A; Etaiw, Safaa El-Din H

    2002-11-01

    The fluorescence decays of safranine T were studied in different homogeneous solvents and heterogeneous micellar solutions. It has been found that micellization leads to an increase in the lifetime. The lifetime distributions were studied in micelles and homogeneous media. It was found that the different half-width distributions of the dye in different micelles are related to the different orientation of the dye in different micelles. Also, the fluorescence quenching of safranine T by 4,6-disubstituted-3-cyanopyridin-2(1H)-thiones was studied in chloroform, methanol and acetonitrile as well as in different micelles. In heterogeneous media the kq values for quenching of safranine T by thiones in various micelles increase on the following order: kq(CTAB) safranine T and therefore the quenching process will be less significant.

  7. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, John L.; Smith, Richard D.

    1993-01-01

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W.sub.o that determines the maximum size of the reverse micelles. The maximum ratio W.sub.o of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions.

  8. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  9. Estimation of interfacial acidity of sodium dodecyl sulfate micelles

    Indian Academy of Sciences (India)

    Arghya Dey; G Naresh Patwari

    2011-11-01

    An enhancement in the excited state proton transfer (ESPT) processes of coumarin-102 (C-102) dye was observed upon addition of salicylic acid and hydrochloric acid in sodium dodecyl sulfate (SDS) micellar solution. The phenomenon was observed only in the micellar medium of anionic surfactant SDS and not in case of cationic (CTAB) or neutral (Trition X -100) surfactants. ESPT of C-102 was also observed in aqueous solutions but on addition of very high concentrations of hydrochloric acid. However, on comparing the ratio of the protonated species from the emission spectra in the presence and absence of SDS micelle, a conclusive estimation of the local proton concentration at the Stern layer of SDS micelles could be evaluated.

  10. Organic hydrogels as potential sorbent materials for water purification

    Science.gov (United States)

    Linardatos, George; Bekiari, Vlasoula; Bokias, George

    2014-05-01

    Hydrogels are three-dimensional, hydrophilic, polymeric networks capable to adsorb large amounts of water or biological fluids. The networks are composed of homopolymers or copolymers and are insoluble due to the presence of chemical or physical cross-links. Depending on the nature of the structural units, swelling or shrinking of these gels can be activated by several external stimuli, such as solvent, heat, pH, electric stimuli. As a consequence, these materials are attractive for several applications in a variety of fields: drug delivery, muscle mimetic soft linear actuators, hosts of nanoparticles and semiconductors, regenerative medicine etc. Of special interest is the application of hydrogels for water purification, since they can effectively adsorb several water soluble pollutants such as metal ions, inorganic or organic anions, organic dyestaff, etc. In the present work, anionic hydrogels bearing negatively charged -COO- groups were prepared and investigated. These are based on the anionic monomer sodium acrylate (ANa) and the nonionic one N,N-dimethylacrylamide (DMAM). A series of copolymeric hydrogels (P(DMAM-co-ANax) were synthesized. The molar content x of ANa units (expressing the molar charged content of the hydrogel) varies from 0 (nonionic poly(N,N-dimethylacrylamide), PDMAM, hydrogel) up to 1 (fully charged poly(sodium acrylate), PANa, hydrogel). The hydrogels were used to extract organic or inorganic solutes from water. Cationic and anionic model dyes, as well as multivalent inorganic ions, have been studied. It is found that cationic dyes are strongly adsorbed and retained by the hydrogels, while adsorbance of anionic dyes was negligible. Both maximum adsorption and equilibrium binding constant depend on the chemical structure of the dye, the presence of functional chemical groups and the hydrophobic-hydrophilic balance. In the case of metal cations, adsorption depends mostly on the charge of the cation. In addition, crucial factors controlling

  11. Cell protective, ABC triblock polymer-based thermoresponsive hydrogels with ROS-triggered degradation and drug release.

    Science.gov (United States)

    Gupta, Mukesh K; Martin, John R; Werfel, Thomas A; Shen, Tianwei; Page, Jonathan M; Duvall, Craig L

    2014-10-22

    A combination of anionic and RAFT polymerization was used to synthesize an ABC triblock polymer poly[(propylenesulfide)-block-(N,N-dimethylacrylamide)-block-(N-isopropylacrylamide)] (PPS-b-PDMA-b-PNIPAAM) that forms physically cross-linked hydrogels when transitioned from ambient to physiologic temperature and that incorporates mechanisms for reactive oxygen species (ROS) triggered degradation and drug release. At ambient temperature (25 °C), PPS-b-PDMA-b-PNIPAAM assembled into 66 ± 32 nm micelles comprising a hydrophobic PPS core and PNIPAAM on the outer corona. Upon heating to physiologic temperature (37 °C), which exceeds the lower critical solution temperature (LCST) of PNIPAAM, micelle solutions (at ≥2.5 wt %) sharply transitioned into stable, hydrated gels. Temperature-dependent rheology indicated that the equilibrium storage moduli (G') of hydrogels at 2.5, 5.0, and 7.5 wt % were 20, 380, and 850 Pa, respectively. The PPS-b-PDMA-b-PNIPAAM micelles were preloaded with the model drug Nile red, and the resulting hydrogels demonstrated ROS-dependent drug release. Likewise, exposure to the peroxynitrite generator SIN-1 degraded the mechanical properties of the hydrogels. The hydrogels were cytocompatible in vitro and were demonstrated to have utility for cell encapsulation and delivery. These hydrogels also possessed inherent cell-protective properties and reduced ROS-mediated cellular death in vitro. Subcutaneously injected PPS-b-PDMA-b-PNIPAAM polymer solutions formed stable hydrogels that sustained local release of the model drug Nile red for 14 days in vivo. These collective data demonstrate the potential use of PPS-b-PDMA-b-PNIPAAM as an injectable, cyto-protective hydrogel that overcomes conventional PNIPAAM hydrogel limitations such as syneresis, lack of degradability, and lack of inherent drug loading and environmentally responsive release mechanisms.

  12. Radiation preparation of PVA/CMC copolymers and their application in removal of dyes

    Energy Technology Data Exchange (ETDEWEB)

    Taleb, Manal F. Abou, E-mail: abutalib_m@yahoo.com [National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority, Nasr City, P.O. Box 29, Cairo 11371 (Egypt); El-Mohdy, H. L. Abd; El-Rehim, H. A. Abd [National Center for Radiation Research and Technology (NCRRT), Atomic Energy Authority, Nasr City, P.O. Box 29, Cairo 11371 (Egypt)

    2009-08-30

    Copolymer hydrogels composed of poly(vinyl alcohol) (PVA) and carboxymethyl cellulose (CMC) was prepared by using electron beam irradiation as crosslinking agent. The copolymers were characterized by FTIR and the physical properties such as gelation. The thermal behavior and swelling properties of the prepared hydrogels were investigated as a function of PVA/CMC composition. The factors effecting adsorption capacity of acid, reactive and direct dyes onto PVA/CMC hydrogel, such as CMC content, pH value of the dye solution, initial concentration and adsorption temperature for dyes were investigated. Thermodynamic study indicated that the values the negative values of {Delta}H suggested that the adsorption process is exothermic. The value of {Delta}H (38.81 kJ/mol) suggested that the electrostatic interaction is the dominant mechanism for the adsorption of dyes on hydrogel.

  13. Thermodynamics of hexadecyltrimethylammonium bromide micelle formation

    Science.gov (United States)

    Velikov, A. A.

    2017-07-01

    The thermodynamic parameters for CTAB micelle formation (Δ H, Δ G, Δ S) are calculated at different temperatures. Critical micelle concentrations CMC1 are determined. The possibility of determining CMC2 is demonstrated.

  14. Achieving micelle control through core crystallinity.

    Science.gov (United States)

    Glavas, Lidija; Olsén, Peter; Odelius, Karin; Albertsson, Ann-Christine

    2013-11-11

    We have designed a pathway for controlling the critical micelle concentration and micelle size of polyester-based systems. This was achieved by creating an array of different copolymers with semicrystalline or amorphous hydrophobic blocks. The hydrophobic block was constructed through ring-opening polymerization of ε-caprolactone, L-lactide, and ε-decalactone, either as homopolymers or random copolymers, using PEG as both the initiator and the hydrophilic block. Micelles formed with amorphous cores exhibited considerably higher critical micelle concentrations than those with semicrystalline cores. Micelles with amorphous cores also became larger in size with an increased molecular weight of the hydrophobic bock, in contrast to micelles with semicrystalline cores, which displayed the opposite behavior. Hence, core crystallinity was found to be a potent tool for tailoring micelle properties and thereby facilitating the optimization of drug delivery systems. The introduction of PEG-PεDL also proved to be a valuable asset in the tuning of micelle properties.

  15. [Tattooing dyes].

    Science.gov (United States)

    Lehmann, G; Pierchalla, P

    1988-01-01

    Nine different tattoo dyes were analysed by various tests. Mixtures of organic dyes and inorganic filler were found; the inorganic filler consisted mainly of titanium dioxide (TiO2). Heavy metals, e.g. mercury, cadmium, or chrome as the common components of the traditional tattoo dyes, are capable of evoking unwanted skin reactions, but were not detected. Tattoo dyes are not officially controlled, and thus it is not known which substances-in addition to those identified by us-are presently used to produce ornamental tattoos. However, our results suggest that classic dyes have been superceded by newer, mainly synthetic dyes.

  16. Dye Painting!

    Science.gov (United States)

    Johnston, Ann

    This resource provides practical instructions for applying color and design directly to fabric. Basic information about the dye painting process is given. The guide addresses the technical aspects of fabric dye and color use and offers suggestions for fabric manipulation and dye application in order to achieve various design effects. This…

  17. Dye Painting!

    Science.gov (United States)

    Johnston, Ann

    This resource provides practical instructions for applying color and design directly to fabric. Basic information about the dye painting process is given. The guide addresses the technical aspects of fabric dye and color use and offers suggestions for fabric manipulation and dye application in order to achieve various design effects. This…

  18. Multifunctional targeting micelle nanocarriers with both imaging and therapeutic potential for bladder cancer

    Directory of Open Access Journals (Sweden)

    Lin TY

    2012-06-01

    Full Text Available Tzu-yin Lin,1 Hongyong Zhang,1 Juntao Luo,2,5 Yuanpei Li,2 Tingjuan Gao,3 Primo N Lara Jr,1,4,6 Ralph de Vere White,4 Kit S Lam,1,2 Chong-Xian Pan,1,3,61Division of Hematology and Oncology, Department of Internal Medicine, 2Department of Biochemistry and Molecular Medicine, 3NSF Center for Biophotonics Science and Technology, School of Medicine, 4Department of Urology, University of California-Davis, Sacramento, CA, 5Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY, 6VA Northern California Health Care System, Mather, CA, USABackground: We previously developed a bladder cancer-specific ligand (PLZ4 that can specifically bind to both human and dog bladder cancer cells in vitro and in vivo. We have also developed a micelle nanocarrier drug-delivery system. Here, we assessed whether the targeting micelles decorated with PLZ4 on the surface could specifically target dog bladder cancer cells.Materials and methods: Micelle-building monomers (ie, telodendrimers were synthesized through conjugation of polyethylene glycol with a cholic acid cluster at one end and PLZ4 at the other, which then self-assembled in an aqueous solution to form micelles. Dog bladder cancer cell lines were used for in vitro and in vivo drug delivery studies.Results: Compared to nontargeting micelles, targeting PLZ4 micelles (23.2 ± 8.1 nm in diameter loaded with the imaging agent DiD and the chemotherapeutic drug paclitaxel or daunorubicin were more efficient in targeted drug delivery and more effective in cell killing in vitro. PLZ4 facilitated the uptake of micelles together with the cargo load into the target cells. We also developed an orthotopic invasive dog bladder cancer xenograft model in mice. In vivo studies with this model showed the targeting micelles were more efficient in targeted drug delivery than the free dye (14.3×; P < 0.01 and nontargeting micelles (1.5×; P < 0.05.Conclusion: Targeting micelles decorated with PLZ4 can selectively

  19. Microwaves initiated synthesis of activated carbon-based composite hydrogel for simultaneous removal of copper(II) ions and direct red 80 dye: A multi-component adsorption system

    OpenAIRE

    Oladipo, Akeem Adeyemi; Gazi, Mustafa

    2015-01-01

    We present a novel microwave initiated preparation of polyacrylamide/activated carbon hydrogel (PAAm-FAc) in this article and characterized by FT-IR, pHzpc and Boehm titration. The adsorbent was assessed for competitive adsorption of copper(II) and direct red 80 from a binary mixture in a single-staged batch process as a function of volume of binary mixture/mass of adsorbent (V0/M0) ratio at varying orders of second pollutant concentration. A competitive, multi-component Langmuir isotherm was...

  20. Mussel-inspired synthesis of polydopamine-functionalized graphene hydrogel as reusable adsorbents for water purification.

    Science.gov (United States)

    Gao, Hongcai; Sun, Yimin; Zhou, Jiajing; Xu, Rong; Duan, Hongwei

    2013-01-23

    We present a one-step approach to polydopamine-modified graphene hydrogel, with dopamine serving as both reductant and surface functionalization agents. The synthetic method is based on the spontaneous polymerization of dopamine and the self-assembly of graphene nanosheets into porous hydrogel structures. Benefiting from the abundant functional groups of polydopamine and the high specific surface areas of graphene hydrogel with three-dimensional interconnected pores, the prepared material exhibits high adsorption capacities toward a wide spectrum of contaminants, including heavy metals, synthetic dyes, and aromatic pollutants. Importantly, the free-standing graphene hydrogel can be easily removed from water after adsorption process, and can be regenerated by altering the pH values of the solution for adsorbed heavy metals or using low-cost alcohols for synthetic dyes and aromatic molecules.

  1. Solvent and solute ingress into hydrogels resolved by a combination of imaging techniques

    Science.gov (United States)

    Wagner, D.; Burbach, J.; Grünzweig, C.; Hartmann, S.; Lehmann, E.; Egelhaaf, S. U.; Hermes, H. E.

    2016-05-01

    Using simultaneous neutron, fluorescence, and optical brightfield transmission imaging, the diffusion of solvent, fluorescent dyes, and macromolecules into a crosslinked polyacrylamide hydrogel was investigated. This novel combination of different imaging techniques enables us to distinguish the movements of the solvent and fluorescent molecules. Additionally, the swelling or deswelling of the hydrogels can be monitored. From the sequence of images, dye and solvent concentrations were extracted spatially and temporally resolved. Diffusion equations and different boundary conditions, represented by different models, were used to quantitatively analyze the temporal evolution of these concentration profiles and to determine the diffusion coefficients of solvent and solutes. Solute size and network properties were varied and their effect was investigated. Increasing the crosslinking ratio or partially drying the hydrogel was found to hinder solute diffusion due to the reduced pore size. By contrast, solvent diffusion seemed to be slightly faster if the hydrogel was only partially swollen and hence solvent uptake enhanced.

  2. Development and evaluation of fast forming nano-composite hydrogel for ocular delivery of diclofenac.

    Science.gov (United States)

    Li, Xingyi; Zhang, Zhaoliang; Chen, Hao

    2013-05-01

    In this paper, a fast forming nano-composite hydrogel was developed for potential application in ocular drug delivery. The optical transmission (OT) as well as rheological properties of nano-composite hydrogel was characterized. The developed nano-composite hydrogel given a high diclofenac micelles loading and provided a sustained release manner of diclofenac within 6h. The developed nano-composite hydrogel formulation was administrated into the eye as flowable solution, quickly forming a hydrogel that is able to resist of the blinking and flushing of tear, yet resulting in the prolonged residence time of pre-corneal. In vivo eye irritation test suggested that the developed nano-composite hydrogel was none-eye irritation might be suitable for various ocular applications. In vivo pharmacokinetic study indicated that the developed nano-composite hydrogel could significantly increase the bioavailability of diclofenac and maintain the concentration of diclofenac in aqueous humor above MEC at least 24h after administration as compared with that of the commercial diclofenac sodium eye drops, which might be able to reduce the frequency of administration for patients.

  3. Functional elastic hydrogel as recyclable membrane for the adsorption and degradation of methylene blue.

    Directory of Open Access Journals (Sweden)

    Song Bao

    Full Text Available Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young's modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g(-1. The hydrogel also exhibited higher separation selectivity to Pb(2+ than Cu(2+. The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables.

  4. Functional elastic hydrogel as recyclable membrane for the adsorption and degradation of methylene blue.

    Science.gov (United States)

    Bao, Song; Wu, Dongbei; Wang, Qigang; Su, Teng

    2014-01-01

    Developing the application of high-strength hydrogels has gained much attention in the fields of medical, pharmacy, and pollutant removal due to their versatility and stimulus-responsive properties. In this presentation, a high-strength freestanding elastic hydrogel membrane was constructed by clay nanosheets, N, N-dimethylacrylamide and 2-acrylamide-2-methylpropanesulfonic acid for adsorption of methylene blue and heavy metal ions. The maximum values of elongation and Young's modulus for 0.5% AMPSNa hydrogel were 1901% and 949.4 kPa, respectively, much higher than those of traditional hydrogels. The adsorptions were confirmed to follow pseudo-second kinetic equation and Langmuir isotherm model fits the data well. The maximum adsorption capacity of hydrogel towards methylene blue was 434.8 mg g(-1). The hydrogel also exhibited higher separation selectivity to Pb(2+) than Cu(2+). The methylene blue adsorbed onto the hydrogel membrane can be photocatalytically degraded by Fenton agent and the hydrogel membrane could be recycled at least five times without obvious loss in mechanical properties. In conclusion, this presentation demonstrates a convenient strategy to prepare tough and elastic clay nanocomposite hydrogel, which can not only be applied as recyclable membrane for the photocatalytic degradation of organic dye, but also for the recovery of valuables.

  5. Hydrogels Constructed from Engineered Proteins.

    Science.gov (United States)

    Li, Hongbin; Kong, Na; Laver, Bryce; Liu, Junqiu

    2016-02-24

    Due to their various potential biomedical applications, hydrogels based on engineered proteins have attracted considerable interest. Benefitting from significant progress in recombinant DNA technology and protein engineering/design techniques, the field of protein hydrogels has made amazing progress. The latest progress of hydrogels constructed from engineered recombinant proteins are presented, mainly focused on biorecognition-driven physical hydrogels as well as chemically crosslinked hydrogels. The various bio-recognition based physical crosslinking strategies are discussed, as well as chemical crosslinking chemistries used to engineer protein hydrogels, and protein hydrogels' various biomedical applications. The future perspectives of this fast evolving field of biomaterials are also discussed.

  6. A thermo-degradable hydrogel with light-tunable degradation and drug release.

    Science.gov (United States)

    Hu, Jingjing; Chen, Yihua; Li, Yunqi; Zhou, Zhengjie; Cheng, Yiyun

    2017-01-01

    The development of thermo-degradable hydrogels is of great importance in drug delivery. However, it still remains a huge challenge to prepare thermo-degradable hydrogels with inherent degradation, reproducible, repeated and tunable dosing. Here, we reported a thermo-degradable hydrogel that is rapidly degraded above 44 °C by a facile chemistry. Besides thermo-degradability, the hydrogel also undergoes rapid photolysis with ultraviolet light. By embedding photothermal nanoparticles or upconversion nanoparticles into the gel, it can release the entrapped cargoes such as dyes, enzymes and anticancer drugs in an on-demand and dose-tunable fashion upon near-infrared light exposure. The smart hydrogel works well both in vitro and in vivo without involving sophisticated syntheses, and is well suited for clinical cancer therapy due to the high transparency and non-invasiveness features of near-infrared light.

  7. Design and synthesis of an amphiphilic graft hydrogel having a hydrophobic domain formed by multiple interactions.

    Science.gov (United States)

    Nitta, Kyohei; Kimoto, Atsushi; Watanabe, Junji

    2016-11-01

    A novel hydrogel having hydrophobic oligo segments and hydrophilic poly(acrylamidoglycolic acid) (PAGA) as pH responsive polymer segments was designed and synthesized to be used as a soft biomaterial. Poly(trimethylene carbonate) (PTMC) as the side chain, for which the degrees of polymerization were 9, 19, and 49, and the composition ratios were 1, 5, and 10mol%, was used as the oligo segment in the hydrogel. The swelling ratio of the hydrogel was investigated under various changes in conditions such as pH, temperature, and hydrogen bonding upon urea addition. Under pH2-11 conditions, the graft gel reversibly swelled and shrank due to the effect of PAGA main chain. The interior morphology and skin layer of the hydrogel was observed by a scanning electron microscope. The hydrogel composed of PAGA as the hydrophilic polymer backbone had a sponge-like structure, with a pore size of approximately 100μm. On the other hand, upon increasing the ratio of trimethylene carbonate (TMC) units in the hydrogel, the pores became smaller or disappeared. Moreover, thickness of the skin layer significantly increased with the swelling ratio depended on the incorporation ratios of the PTMC macromonomer. Molecular incorporation in the hydrogel was evaluated using a dye as a model drug molecule. These features would play an important role in drug loading. Increasing the ratio of TMC units favored the adsorption of the dye and activation of the incorporation behavior.

  8. Molecular Simulation of Reverse Micelles

    Science.gov (United States)

    Chowdhary, Janamejaya; Ladanyi, Branka

    2009-03-01

    Reverse micelles (RM) are surfactant assemblies containing a nanosized water pool dissolved in a hydrophobic solvent. Understanding their properties is crucial for insight into the effect of confinement on aqueous structure, dynamics as well as physical processes associated with solutes in confinement. We perform molecular dynamics simulations for the RM formed by the surfactant Aerosol-OT (AOT) in isooctane (2,2,4-trimethyl pentane) in order to study the effect of reverse micelle size on the aqueous phase. The structure of the RM is quantified in terms of the radial and pair density distributions. Dynamics are studied in terms of the mean squared displacements and various orientational time correlation functions in different parts of the RM so as to understand the effect of proximity to the interface on aqueous dynamics. Shape fluctuations of the RM are also analyzed.

  9. Ultrasound-Mediated Polymeric Micelle Drug Delivery.

    Science.gov (United States)

    Xia, Hesheng; Zhao, Yue; Tong, Rui

    2016-01-01

    The synthesis of multi-functional nanocarriers and the design of new stimuli-responsive means are equally important for drug delivery. Ultrasound can be used as a remote, non-invasive and controllable trigger for the stimuli-responsive release of nanocarriers. Polymeric micelles are one kind of potential drug nanocarrier. By combining ultrasound and polymeric micelles, a new modality (i.e., ultrasound-mediated polymeric micelle drug delivery) has been developed and has recently received increasing attention. A major challenge remaining in developing ultrasound-responsive polymeric micelles is the improvement of the sensitivity or responsiveness of polymeric micelles to ultrasound. This chapter reviews the recent advance in this field. In order to understand the interaction mechanism between ultrasound stimulus and polymeric micelles, ultrasound effects, such as thermal effect, cavitation effect, ultrasound sonochemistry (including ultrasonic degradation, ultrasound-initiated polymerization, ultrasonic in-situ polymerization and ultrasound site-specific degradation), as well as basic micellar knowledge are introduced. Ultrasound-mediated polymeric micelle drug delivery has been classified into two main streams based on the different interaction mechanism between ultrasound and polymeric micelles; one is based on the ultrasound-induced physical disruption of the micelle and reversible release of payload. The other is based on micellar ultrasound mechanochemical disruption and irreversible release of payload.

  10. pH Responsiveness of hydrogels formed by telechelic polyampholytes.

    Science.gov (United States)

    Dyakonova, Margarita A; Gotzamanis, George; Niebuur, Bart-Jan; Vishnevetskaya, Natalya S; Raftopoulos, Konstantinos N; Di, Zhenyu; Filippov, Sergey K; Tsitsilianis, Constantinos; Papadakis, Christine M

    2017-05-21

    We investigate the influence of pH on the rheological and structural properties of hydrogels formed by hydrophobic association of the sticky ends of the triblock terpolymer poly(methyl methacrylate)-b-poly(2-(diethylamino)ethyl methacrylate-co-methacrylic acid)-b-poly(methyl methacrylate) (PMMA-b-P(DEA-co-MAA)-b-PMMA). The middle block is a weak polyampholyte having a pH dependent charge density and sign, which enables tuning of the rheological and structural properties by pH variation. Small-angle neutron scattering (SANS) studies of solutions in D2O at 0.05 wt% and pH 3.0 reveal clusters of interconnected spherical micelles having PMMA cores, stabilized by repulsive ionic interactions in the middle polyampholyte block. With increasing pH, the degree of ionization of the DEA units decreases, whereas the one of the MAA units increases, resulting in a complete loss of the correlation between these micelles. At a concentration of 3 wt% at low pH values, the system forms a gel with charged fuzzy spheres from PMMA interacting via a screened Coulomb potential. With increasing pH, the gel disintegrates due to the decrease in the effective charge on the micelles. At both concentrations, the hydrophobic aggregation of micelles is observed near the isoelectric point. At pH 3.0-7.4, the autocorrelation functions measured by rotational dynamic light scattering at 3 wt% exhibit a decay steeper than single exponential, which confirms that the gels are frozen, presumably due to the glassy PMMA cores and hydrophobic interpolyelectrolyte complexes. At pH 11, the diffusion of single micelles is observed in addition to the frozen dynamics.

  11. Novel thermosensitive hydrogel for preventing formation of abdominal adhesions

    Directory of Open Access Journals (Sweden)

    Gao X

    2013-07-01

    Full Text Available Xiang Gao,1,2 Xiaohui Deng,3 Xiawei Wei,2 Huashan Shi,2 Fengtian Wang,2 Tinghong Ye,2 Bin Shao,2 Wen Nie,2 Yuli Li,2 Min Luo,2 Changyang Gong,2 Ning Huang1 1Department of Pathophysiology, College of Preclinical and Forensic Medical Sciences, Sichuan University, Chengdu, 2State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, 3Department of Human Anatomy, Xinxiang Medical University, Xinxiang, People’s Republic of China Abstract: Adhesions can form after almost any type of abdominal surgery. Postoperative adhesions can be prevented by improved surgical techniques, such as reducing surgical trauma, preventing ischemia, and avoiding exposure of the peritoneal cavity to foreign materials. Although improved surgical techniques can potentially reduce formation of adhesions, they cannot be eliminated completely. Therefore, finding more effective methods to prevent postoperative adhesions is imperative. Recently, we found that a novel thermosensitive hydrogel, ie, poly(ε-caprolactone-poly(ethylene glycol-poly(ε-caprolactone (PCEC had the potential to prevent postoperative adhesions. Using the ring-opening polymerization method, we prepared a PCEC copolymer which could be dissolved and assembled at 55°C into PCEC micelles with mean size of 25 nm. At body temperature, a solution containing PCEC micelles could convert into a hydrogel. The PCEC copolymer was biodegradable and had low toxicity in vitro and in vivo. We found that most animals in a hydrogel-treated group (n = 10 did not develop adhesions. In contrast, 10 untreated animals developed adhesions that could only be separated by sharp dissection (P < 0.001. The hydrogel could adhere to peritoneal wounds and degraded gradually over 7–9 days, transforming into a viscous fluid that was completely absorbed within 12 days. The injured parietal and visceral peritoneum remesothelialized over about seven and nine days

  12. Complex Coacervate Core Micelles with Spectroscopic Labels for Diffusometric Probing of Biopolymer Networks.

    Science.gov (United States)

    Bourouina, Nadia; de Kort, Daan W; Hoeben, Freek J M; Janssen, Henk M; Van As, Henk; Hohlbein, Johannes; van Duynhoven, John P M; Kleijn, J Mieke

    2015-11-24

    We present the design, preparation, and characterization of two types of complex coacervate core micelles (C3Ms) with cross-linked cores and spectroscopic labels and demonstrate their use as diffusional probes to investigate the microstructure of percolating biopolymer networks. The first type consists of poly(allylamine hydrochloride) (PAH) and poly(ethylene oxide)-poly(methacrylic acid) (PEO-b-PMAA), labeled with ATTO 488 fluorescent dyes. We show that the size of these probes can be tuned by choosing the length of the PEO-PMAA chains. ATTO 488-labeled PEO113-PMAA15 micelles are very bright with 18 dye molecules incorporated into their cores. The second type is a (19)F-labeled micelle, for which we used PAH and a (19)F-labeled diblock copolymer tailor-made from poly(ethylene oxide)-poly(acrylic acid) (mPEO79-b-PAA14). These micelles contain approximately 4 wt % of (19)F and can be detected by (19)F NMR. The (19)F labels are placed at the end of a small spacer to allow for the necessary rotational mobility. We used these ATTO- and (19)F-labeled micelles to probe the microstructures of a transient gel (xanthan gum) and a cross-linked, heterogeneous gel (κ-carrageenan). For the transient gel, sensitive optical diffusometry methods, including fluorescence correlation spectroscopy, fluorescence recovery after photobleaching, and super-resolution single nanoparticle tracking, allowed us to measure the diffusion coefficient in networks with increasing density. From these measurements, we determined the diameters of the constituent xanthan fibers. In the heterogeneous κ-carrageenan gels, bimodal nanoparticle diffusion was observed, which is a signpost of microstructural heterogeneity of the network.

  13. Stable Polymer Micelles Formed by Metal Coordination

    NARCIS (Netherlands)

    Wang, Junyou; Stuart, Martien A. Cohen; Marcelis, Antonius T. M.; Colomb-Delsuc, Mathieu; Otto, Sijbren; van der Gucht, Jasper

    2012-01-01

    Metal-containing polymer micelles have attracted much attention due to their potential for medical and nanotechnological applications. In this paper, we present a method to prepare stable metal-containing polymer micelles. A diblock copolymer poly(4-vinylpyridine)-b-poly(ethylene oxide) (P4VP(48)-b-

  14. Synthesis of photolabile fluorescent polymeric micelles.

    Science.gov (United States)

    Park, Teahoon; You, Jungmok; Oikawa, Hidetoshi; Kim, Eunkyoung

    2014-11-01

    A new amphiphilic block copolymers were synthesized with the atom transfer radical polymerization (ATRP) method. Then, the micelle structures were fabricated with a self-assembly method for application in nanocarriers and sensing. The fluorescent intensity was increased by a factor of 4 in the micelle solution due to more stacked pyrene moieties. The core-shell structure of the micelle was confirmed by HR-TEM images. The pyrene moieties were positioned in the core of the micelle, and the surface consisted of hydrophilic PMMA blocks. The ester bond of the polymer backbone was breakable by irradiation with UV light. Therefore, the micelle structure was deformed after UV irradiation, and the excimer peak was drastically reduced as the monomer peak appeared. The deformation of micelle structures was clearly confirmed by FE-SEM and NMR analysis. These photolabile polymeric micelles may be widely useful for photo-stimulative nanocarriers as well as for the design of new functional micelles with many other chromophores.

  15. Formation of micelles with complex coacervate cores.

    NARCIS (Netherlands)

    Cohen Stuart, M.A.; Besseling, N.A.M.; Fokkink, R.G.

    1998-01-01

    Micelles are commonly regarded as colloidal structures spontaneously formed by amphiphilic molecules, that is, molecules consisting of two distinct parts of which one is soluble and the other is insoluble. This definition is too restrictive: other kinds of molecules can also form micelles. We report

  16. Template-synthesized opal hydrogels

    Institute of Scientific and Technical Information of China (English)

    LI Jun; JI Lijun; RONG Jianhua; YANG Zhenzhong

    2003-01-01

    Opal hydrogels could be synthesized with polymer inverse opal template. A pH responsive opal N-iso- propylacrylamide/acrylic acid copolymerized hydrogel was prepared as an example. The ordered structure and response to pH were investigated. Through the sol-gel process of tetrabutyl titanate, opal titania was obtained with the opal hydrogel template.

  17. End Group Effects on the Hydrogel Formation of PEO-PPO-PEO Triblock Copolymers

    Science.gov (United States)

    Cohen, Aaron; Ryu, Chang Y.; Jung, Gyoo Y.; Hwang, Hee Sung

    2012-02-01

    Pluronic F108, a triblock copolymer consisting of outer polyethylene oxide (PEO) chains and an inner polypropylene oxide (PPO) chains, has been shown to be an effective hydrogel matrix for DNA separation by capillary electrophoresis using single-stranded conformation polymorphism. This presentation will discuss a new pathway to potentially enhance the separation abilities of F108 by altering the chain end groups of the block copolymers. F108 is believed to form a micelle in aqueous solutions with the hydrophobic group in the interior, thus we expect considerable interaction between the DNA sample and the end groups found at the hydrophilic brush layers of the micelle. The rheological properties of end group derivatives of F108, in combination of small angle x-ray scattering, can reveal structural differences in the micelles. In particular, gelation temperature of the end group derivatives can be linked to differences in the micelle structure. Dynamic light scattering can also be used to determine the effects of chain end groups on the hydrodynamic size of the block copolymer micelles in dilute solution.

  18. FOLATE-TARGETED OPTICAL AND MAGNETIC RESONANCE DUALMODALITY PCL-b-PEG MICELLES FOR TUMOR IMAGING*

    Institute of Scientific and Technical Information of China (English)

    Xiao-ming Sun; Jin-xia Xu; Jian-bin Tang; Mei-hua Sui; You-qing Shen

    2011-01-01

    A biodegradable tumor targeting nano-probe based on poly(ε-caprolactone)-b-poly(ethylene glycol) block copolymer (PCL-b-PEG)micelle functionalized with a magnetic resonance imaging (MRI) contrast agent diethylenetriaminepenmacetic acid-gadolinium (DTPA-Gd3+) on the shell and a near-infrared (NIR) dye in the core for magnetic resonance and optical dual-modality imaging was prepared. The longitudinal relaxivity (r1) of the PCL-b-PEGDTPA-Gd3+ micelle was 13.4 (mmol/L)-1s-1, three folds of that of DTPA-Gd3+, and higher than that of many polymeric contrast agents with similar structures. The in vivo optical imaging of a nude mouse bearing xenografied breast tumor showed that the dual-modality micelle preferentially accumulated in the tumor via the folic acid-mediated active targeting and the passive accumulation by the enhanced permeability and retention (EPR) effect. The results iadicated that the dualmodality micelle is a promising nano-probe for cancer detection and diagnosis.

  19. Fabrication of poly(ethylene glycol) hydrogel microstructures using photolithography

    Science.gov (United States)

    Revzin, A.; Russell, R. J.; Yadavalli, V. K.; Koh, W. G.; Deister, C.; Hile, D. D.; Mellott, M. B.; Pishko, M. V.

    2001-01-01

    The fabrication of hydrogel microstructures based upon poly(ethylene glycol) diacrylates, dimethacrylates, and tetraacrylates patterned photolithographically on silicon or glass substrates is described. A silicon/silicon dioxide surface was treated with 3-(trichlorosilyl)propyl methacrylate to form a self-assembled monolayer (SAM) with pendant acrylate groups. The SAM presence on the surface was verified using ellipsometry and time-of-flight secondary ion mass spectrometry. A solution containing an acrylated or methacrylated poly(ethylene glycol) derivative and a photoinitiator (2,2-dimethoxy-2-phenylacetophenone) was spin-coated onto the treated substrate, exposed to 365 nm ultraviolet light through a photomask, and developed with either toluene, water, or supercritical CO2. As a result of this process, three-dimensional, cross-linked PEG hydrogel microstructures were immobilized on the surface. Diameters of cylindrical array members were varied from 600 to 7 micrometers by the use of different photomasks, while height varied from 3 to 12 micrometers, depending on the molecular weight of the PEG macromer. In the case of 7 micrometers diameter elements, as many as 400 elements were reproducibly generated in a 1 mm2 square pattern. The resultant hydrogel patterns were hydrated for as long as 3 weeks without delamination from the substrate. In addition, micropatterning of different molecular weights of PEG was demonstrated. Arrays of hydrogel disks containing an immobilized protein conjugated to a pH sensitive fluorophore were also prepared. The pH sensitivity of the gel-immobilized dye was similar to that in an aqueous buffer, and no leaching of the dye-labeled protein from the hydrogel microstructure was observed over a 1 week period. Changes in fluorescence were also observed for immobilized fluorophore labeled acetylcholine esterase upon the addition of acetyl acholine.

  20. Polar Solvents Trigger Formation of Reverse Micelles.

    Science.gov (United States)

    Khoshnood, Atefeh; Firoozabadi, Abbas

    2015-06-09

    We use molecular dynamics simulations and molecular thermodynamics to investigate the formation of reverse micelles in a system of surfactants and nonpolar solvents. Since the early observation of reverse micelles, the question has been whether the existence of polar solvent molecules such as water is the driving force for the formation of reverse micelles in nonpolar solvents. In this work, we use a simple coarse-grained model of surfactants and solvents to show that a small number of polar solvent molecules triggers the formation of large permanent aggregates. In the absence of polar molecules, both the thermodynamic model and molecular simulations show that small aggregates are more populated in the solution and larger ones are less frequent as the system evolves over time. The size and shape of reverse micelles depend on the size of the polar core: the shape is spherical for a large core and ellipsoidal for a smaller one. Using the coarse-grained model, we also investigate the effect of temperature and surfactant tail length. Our results reveal that the number of surfactant molecules in the micelle decreases as the temperature increases, but the average diameter does not change because the size of the polar core remains invariant. A reverse micelle with small polar core attracts fewer surfactants when the tail is long. The uptake of solvent particles by a micelle of longer surfactant tail is less than shorter ones when the polar solvent particles are initially distributed randomly.

  1. Casein micelle structure: a concise review

    Directory of Open Access Journals (Sweden)

    Chanokphat Phadungath

    2005-01-01

    Full Text Available Milk is a complex biological fluid with high amount of proteins, lipid and minerals. The function of milk is to supply nutrients such as essential amino acids required for the growth of the newborn. In addition, due to the importance of casein and casein micelles for the functional behavior of dairy products, the nature and structure of casein micelles have been studied extensively. However, the exact structure of casein micelles is still under debate. Various models for casein micelle structure have been proposed. Most of the proposedmodels fall into three general categories, which are: coat-core, subunit (sub-micelles, and internal structure models. The coat-core models, proposed by Waugh and Nobel in 1965, Payens in 1966, Parry and Carroll in 1969, and Paquin and co-workers in 1987, describe the micelle as an aggregate of caseins with outer layer differing in composition form the interior, and the structure of the inner part is not accurately identified. The sub-micelle models, proposed by Morr in 1967, Slattery and Evard in 1973, Schmidt in 1980, Walstra in1984, and Ono and Obata in 1989, is considered to be composed of roughly spherical uniform subunits. The last models, the internal structure models, which were proposed by Rose in 1969, Garnier and Ribadeau- Dumas in 1970, Holt in 1992, and Horne in 1998, specify the mode of aggregation of the different caseins.

  2. Chemical reactions in reverse micelle systems

    Science.gov (United States)

    Matson, Dean W.; Fulton, John L.; Smith, Richard D.; Consani, Keith A.

    1993-08-24

    This invention is directed to conducting chemical reactions in reverse micelle or microemulsion systems comprising a substantially discontinuous phase including a polar fluid, typically an aqueous fluid, and a microemulsion promoter, typically a surfactant, for facilitating the formation of reverse micelles in the system. The system further includes a substantially continuous phase including a non-polar or low-polarity fluid material which is a gas under standard temperature and pressure and has a critical density, and which is generally a water-insoluble fluid in a near critical or supercritical state. Thus, the microemulsion system is maintained at a pressure and temperature such that the density of the non-polar or low-polarity fluid exceeds the critical density thereof. The method of carrying out chemical reactions generally comprises forming a first reverse micelle system including an aqueous fluid including reverse micelles in a water-insoluble fluid in the supercritical state. Then, a first reactant is introduced into the first reverse micelle system, and a chemical reaction is carried out with the first reactant to form a reaction product. In general, the first reactant can be incorporated into, and the product formed in, the reverse micelles. A second reactant can also be incorporated in the first reverse micelle system which is capable of reacting with the first reactant to form a product.

  3. Formation and Fluorimetric Characterization of Micelles in a Micro-flow Through System with Static Micro Mixer

    Directory of Open Access Journals (Sweden)

    J. Michael Köhler

    2007-10-01

    Full Text Available The formation and behaviour of micelles of sodium dodecylsulfate in water byuse of a static micro mixer were studied. Trisbipyridylruthenium(II was applied asindicator dye, 9-methylanthracene was used for fluorescence quenching. All experimentswere carried out by a micro fluid arrangement with three syringe pumps, a 2 1 two-stepstatic micro mixer (IPHT Jena and a on-line micro fluorimetry including a luminescencediode for excitation, a blue glass filter (BG 7, Linos, two edge filters (RG 630, Linos anda photo counting module (MP 900, Perkin Elmer. It was possible to measure thefluorescence inside the PTFE tube (inner diameter 0.5 mm directly. A linear dependenceof fluorescence intensity from dye concentration was observed in absence of quencher andsurfactant as expected. An aggregation number of about 62 was found in the flow raterange between 300 and 800 μL/min. The fluorescence intensity increases slightly, butsignificant with increasing flow rate, if no quencher is present. In the presence of quencher,the fluorescence intensity decreases with decreasing surfactant concentration and withenhanced flow rate. The strength of the flow rate effect on the fluorescence increases withdecreasing surfactant concentration. The size of micelles was determined in micro channelsby the micro fluorimetric method in analogy to the conventional system. The micellesextract the quencher from the solution and lower, this way, the quenching effect. The sizeof micelles was estimated and it could be shown, that the flow rate has only low effect onthe aggregation number at the investigated flow rates. The effect of flow rate andsurfactant concentration on the fluorescence in the presence of quencher was interpreted asa shift in the micelle concentration due to the shear forces. It is expected, that thefluorescence intensity is lowered, if more quencher molecules are molecular disperse distributed inside the solution. Obviously, the lowered fluorescence

  4. Fabrication of polyaniline hydrogel: Synthesis, characterization and adsorption of methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Bo; Chen, Zhonghui; Cai, Lu; Chen, Zhimin; Fu, Jianwei; Xu, Qun, E-mail: qunxu@zzu.edu.cn

    2015-11-30

    Graphical abstract: - Highlights: • The PAni hydrogel was synthesized using phytic acid as a dopant and cross-linking agent. • The synthesized PAni hydrogel has a big adsorption capacity for MB. • The pseudo-second-order model is available to describe the adsorption of MB. • The Langmuir model is adaptive for the adsorption of MB. • The adsorbent was a specific adsorbent for the removal of MB. - Abstract: Polyaniline (PAni) hydrogel was synthesized in a facial method by using phytic acid as both dopant and cross-linking agent. Then the fabricated hydrogel was employed as an efficient adsorbent to remove the methylene blue (MB) in an aqueous solution. The as-synthesized PAni hydrogel was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The characterization results indicate that the obtained PAni hydrogel has a 3D structure, which is available for the contact between the adsorbent and dye molecules. During the adsorption, the phytic acid provides a large number of anionic phosphate groups as adsorption sites for MB molecules, which induces the high adsorption capacity up to 71.2 mg/g. The effects of pH, the PAni hydrogel mass and temperatures on adsorption efficiency were studied in details. Further experimental results indicate the adsorption kinetic fits well with the pseudo-second-order kinetic model. Compared with Freundlich model, Langmuir isotherm model was more acceptable to fit the equilibrium adsorption data. Moreover, the conceivable mechanism of the adsorption was also proposed in this work.

  5. Adhesion in hydrogel contacts

    Science.gov (United States)

    Torres, J. R.; Jay, G. D.; Kim, K.-S.; Bothun, G. D.

    2016-05-01

    A generalized thermomechanical model for adhesion was developed to elucidate the mechanisms of dissipation within the viscoelastic bulk of a hyperelastic hydrogel. Results show that in addition to the expected energy release rate of interface formation, as well as the viscous flow dissipation, the bulk composition exhibits dissipation due to phase inhomogeneity morphological changes. The mixing thermodynamics of the matrix and solvent determines the dynamics of the phase inhomogeneities, which can enhance or disrupt adhesion. The model also accounts for the time-dependent behaviour. A parameter is proposed to discern the dominant dissipation mechanism in hydrogel contact detachment.

  6. Supramolecular Hydrogelators and Hydrogels: From Soft Matter to Molecular Biomaterials

    Science.gov (United States)

    2015-01-01

    In this review we intend to provide a relatively comprehensive summary of the work of supramolecular hydrogelators after 2004 and to put emphasis particularly on the applications of supramolecular hydrogels/hydrogelators as molecular biomaterials. After a brief introduction of methods for generating supramolecular hydrogels, we discuss supramolecular hydrogelators on the basis of their categories, such as small organic molecules, coordination complexes, peptides, nucleobases, and saccharides. Following molecular design, we focus on various potential applications of supramolecular hydrogels as molecular biomaterials, classified by their applications in cell cultures, tissue engineering, cell behavior, imaging, and unique applications of hydrogelators. Particularly, we discuss the applications of supramolecular hydrogelators after they form supramolecular assemblies but prior to reaching the critical gelation concentration because this subject is less explored but may hold equally great promise for helping address fundamental questions about the mechanisms or the consequences of the self-assembly of molecules, including low molecular weight ones. Finally, we provide a perspective on supramolecular hydrogelators. We hope that this review will serve as an updated introduction and reference for researchers who are interested in exploring supramolecular hydrogelators as molecular biomaterials for addressing the societal needs at various frontiers. PMID:26646318

  7. Rapidly recovering hydrogel scaffolds from self-assembling diblock copolypeptide amphiphiles

    Science.gov (United States)

    Nowak, Andrew P.; Breedveld, Victor; Pakstis, Lisa; Ozbas, Bulent; Pine, David J.; Pochan, Darrin; Deming, Timothy J.

    2002-05-01

    Protein-based hydrogels are used for many applications, ranging from food and cosmetic thickeners to support matrices for drug delivery and tissue replacement. These materials are usually prepared using proteins extracted from natural sources, which can give rise to inconsistent properties unsuitable for medical applications. Recent developments have utilized recombinant DNA methods to prepare artificial protein hydrogels with specific association mechanisms and responsiveness to various stimuli. Here we synthesize diblock copolypeptide amphiphiles containing charged and hydrophobic segments. Dilute solutions of these copolypeptides would be expected to form micelles; instead, they form hydrogels that retain their mechanical strength up to temperatures of about 90°C and recover rapidly after stress. The use of synthetic materials permits adjustment of copolymer chain length and composition, which we varied to study their effect on hydrogel formation and properties. We find that gelation depends not only on the amphiphilic nature of the polypeptides, but also on chain conformations-α-helix, β-strand or random coil. Indeed, shape-specific supramolecular assembly is integral to the gelation process, and provides a new class of peptide-based hydrogels with potential for applications in biotechnology.

  8. Mathematical Models for Controlled Drug Release Through pH-Responsive Polymeric Hydrogels.

    Science.gov (United States)

    Manga, Ramya D; Jha, Prateek K

    2017-02-01

    Hydrogels consisting of weakly charged acidic/basic groups are ideal candidates for carriers in oral delivery, as they swell in response to pH changes in the gastrointestinal tract, resulting in drug entrapment at low pH conditions of the stomach and drug release at high pH conditions of the intestine. We have developed 1-dimensional mathematical models to study the drug release behavior through pH-responsive hydrogels. Models are developed for 3 different cases that vary in the level of rigor, which together can be applied to predict both in vitro (drug release from carrier) and in vivo (drug concentration in the plasma) behavior of hydrogel-drug formulations. A detailed study of the effect of hydrogel and drug characteristics and physiological conditions is performed to gain a fundamental insight into the drug release behavior, which may be useful in the design of pH-responsive drug carriers. Finally, we describe a successful application of these models to predict both in vitro and in vivo behavior of docetaxel-loaded micelle in a pH-responsive hydrogel, as reported in a recent experimental study. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  9. Micelle Catalysis of an Aromatic Substitution Reaction

    Science.gov (United States)

    Corsaro, Gerald; Smith J. K.

    1976-01-01

    Describes an experiment in which the iodonation of aniline reaction is shown to undergo catalysis in solution of sodium lauryl sulfate which forms micelles with negatively charged pseudo surfaces. (MLH)

  10. Polysaccharide-Based Micelles for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Nan Zhang

    2013-05-01

    Full Text Available Delivery of hydrophobic molecules and proteins has been an issue due to poor bioavailability following administration. Thus, micelle carrier systems are being investigated to improve drug solubility and stability. Due to problems with toxicity and immunogenicity, natural polysaccharides are being explored as substitutes for synthetic polymers in the development of new micelle systems. By grafting hydrophobic moieties to the polysaccharide backbone, self-assembled micelles can be readily formed in aqueous solution. Many polysaccharides also possess inherent bioactivity that can facilitate mucoadhesion, enhanced targeting of specific tissues, and a reduction in the inflammatory response. Furthermore, the hydrophilic nature of some polysaccharides can be exploited to enhance circulatory stability. This review will highlight the advantages of polysaccharide use in the development of drug delivery systems and will provide an overview of the polysaccharide-based micelles that have been developed to date.

  11. Casein Micelle Dispersions under Osmotic Stress

    OpenAIRE

    Bouchoux, Antoine; Cayemitte, Pierre-Emerson; Jardin, Julien; Gésan-Guiziou, Geneviève; Cabane, Bernard

    2009-01-01

    Casein micelles dispersions have been concentrated and equilibrated at different osmotic pressures using equilibrium dialysis. This technique measured an equation of state of the dispersions over a wide range of pressures and concentrations and at different ionic strengths. Three regimes were found. i), A dilute regime in which the osmotic pressure is proportional to the casein concentration. In this regime, the casein micelles are well separated and rarely interact, whereas the osmotic press...

  12. Removal of dye by carboxymethyl cellulose, acrylamide and graphene oxide via a free radical polymerization process.

    Science.gov (United States)

    Varaprasad, Kokkarachedu; Jayaramudu, Tippabattini; Sadiku, Emmanuel Rotimi

    2017-05-15

    Carboxymethyl cellulose has been used for the design of novel engineered hydrogels in order to obtain effective three-dimensional structures for industrial applications. In this work, dye removal carboxymethyl cellulose-acrylamide-graphene oxide (CMC-AM-GO) hydrogels were prepared by a free-radical polymerization method. The GO was developed by the modified Hummers method. The CMC-AM-GO and GO were characterized by FTIR, XRD and SEM. The swelling and swelling kinetics were calculated using gravimetric process. The kinetic parameter, swelling exponent values [n=0.59-0.7507] explained the fact that the CMC-AM-GO hydrogles have super Case II diffusion transport mechanism. CMCx-AM-GO (x=1-4) and CMC-AM hydrogels were used for removal of Acid Blue-133. The result explains that composite hydrogels significantly removed the acid blue when compared to the neat hydrogel. The maximum AB absorption (185.45mg/g) capacity was found in the case of CMC2-AM-GO hydrogel. Therefore, cellulose-based GO hydrogels can be termed as smart systems for the abstraction of dye in water purification applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Polymeric micelles for acyclovir drug delivery.

    Science.gov (United States)

    Sawdon, Alicia J; Peng, Ching-An

    2014-10-01

    Polymeric prodrug micelles for delivery of acyclovir (ACV) were synthesized. First, ACV was used directly to initiate ring-opening polymerization of ɛ-caprolactone to form ACV-polycaprolactone (ACV-PCL). Through conjugation of hydrophobic ACV-PCL with hydrophilic methoxy poly(ethylene glycol) (MPEG) or chitosan, polymeric micelles for drug delivery were formed. (1)H NMR, FTIR, and gel permeation chromatography were employed to show successful conjugation of MPEG or chitosan to hydrophobic ACV-PCL. Through dynamic light scattering, zeta potential analysis, transmission electron microscopy, and critical micelle concentration (CMC), the synthesized ACV-tagged polymeric micelles were characterized. It was found that the average size of the polymeric micelles was under 200nm and the CMCs of ACV-PCL-MPEG and ACV-PCL-chitosan were 2.0mgL(-1) and 6.6mgL(-1), respectively. The drug release kinetics of ACV was investigated and cytotoxicity assay demonstrates that ACV-tagged polymeric micelles were non-toxic.

  14. Nonionic reverse micelles near the critical point.

    Science.gov (United States)

    Shrestha, Lok Kumar; Shrestha, Rekha Goswami

    2013-01-01

    We report shape, size, and internal cross-sectional structure of diglycerol monomyristate (C₁₄G₂) reverse micelles in n-hexadecane near the critical point using small-angle X-ray scattering (SAXS). Pair-distance distribution function, p(r), which gives structural information in real-space, was obtained by indirect Fourier transformation (IFT) method. The p(r) showed a clear picture of rodlike micelles at higher temperatures well above the critical point (micellar solution phase separates into two immiscible liquids at ~ 48°C). At a fixed surfactant concentration (5% C₁₄G₂), decrease in temperature increases the micellar size monotonously and surprisingly shape of the p(r) curve at 50°C; close to the critical point, mimics the shape of the two dimensional disk-like micelles indicating the onset of critical fluctuations (attractive interactions among rodlike micelles forming a weak network). A similar behavior has been observed with normal micelles in aqueous system near the critical point. When the system is heated to 60°C, shape of the p(r) curve regains rodlike structure. At fixed temperature of 60°C, increase in C₁₄G₂ concentration induced one dimensional micellar growth. Maximum length of micelles increases from ca. 23.5 to 46.0 nm upon increasing concentration from 1 to 12% keeping cross section diameter apparently unchanged at ca. 4.0 nm.

  15. Flexible pH-Sensing Hydrogel Fibers for Epidermal Applications.

    Science.gov (United States)

    Tamayol, Ali; Akbari, Mohsen; Zilberman, Yael; Comotto, Mattia; Lesha, Emal; Serex, Ludovic; Bagherifard, Sara; Chen, Yu; Fu, Guoqing; Ameri, Shideh Kabiri; Ruan, Weitong; Miller, Eric L; Dokmeci, Mehmet R; Sonkusale, Sameer; Khademhosseini, Ali

    2016-03-01

    Epidermal pH is an indication of the skin's physiological condition. For example, pH of wound can be correlated to angiogenesis, protease activity, bacterial infection, etc. Chronic nonhealing wounds are known to have an elevated alkaline environment, while healing process occurs more readily in an acidic environment. Thus, dermal patches capable of continuous pH measurement can be used as point-of-care systems for monitoring skin disorder and the wound healing process. Here, pH-responsive hydrogel fibers are presented that can be used for long-term monitoring of epidermal wound condition. pH-responsive dyes are loaded into mesoporous microparticles and incorporated into hydrogel fibers using a microfluidic spinning system. The fabricated pH-responsive microfibers are flexible and can create conformal contact with skin. The response of pH-sensitive fibers with different compositions and thicknesses are characterized. The suggested technique is scalable and can be used to fabricate hydrogel-based wound dressings with clinically relevant dimensions. Images of the pH-sensing fibers during real-time pH measurement can be captured with a smart phone camera for convenient readout on-site. Through image processing, a quantitative pH map of the hydrogel fibers and the underlying tissue can be extracted. The developed skin dressing can act as a point-of-care device for monitoring the wound healing process.

  16. Steroidal Surfactants: Detection of Premicellar Aggregation, Secondary Aggregation Changes in Micelles, and Hosting of a Highly Charged Negative Substance.

    Science.gov (United States)

    Barnadas-Rodríguez, Ramon; Cladera, Josep

    2015-08-25

    CHAPSO and CHAPS are zwitterionic surfactants derived from bile salts which are usually employed in protein purification and for the preparation of liposomes and bicelles. Despite their spread use, there are significant discrepancies on the critical concentrations that determine their aggregation behavior. In this work, we study the interaction between these surfactants with the negative fluorescent dye pyranine (HPTS) by absorbance, fluorescence, and infrared spectrometry to establish their concentration-dependent aggregation. For the studied surfactants, we detect three critical concentrations showing their concentration-dependent presence as a monomeric form, premicellar aggregates, micelles, and a second type of micelle in aqueous medium. The nature of the interaction of HPTS with the surfactants was studied using analogues of their tails and the negative bile salt taurocholate (TC) as reference for the sterol ring. The results indicate that the chemical groups involved are the hydroxyl groups of the polar face of the sterol ring and the sulfonate groups of the dye. This interaction causes not only the incorporation of the negative dye in CHAPSO and CHAPS micelles but also its association with their premicellar aggregates. Surprisingly, this hosting behavior for a negative charged molecule was also detected for the negative bile salt TC, bypassing, in this way, the electrostatic repulsion between the guest and the host.

  17. Bioresponsive systems based on polygalacturonate containing hydrogels.

    Science.gov (United States)

    Schneider, Konstantin P; Rollett, Alexandra; Wehrschuetz-Sigl, Eva; Hasmann, Andrea; Zankel, Armin; Muehlebach, Andreas; Kaufmann, Franz; Guebitz, Georg M

    2011-04-07

    Polysaccharide acid (PSA) based devices (consisting of alginic acid and polygalacturonic acid) were investigated for the detection of contaminating microorganisms. PSA-CaCl(2) hydrogel systems were compared to systems involving covalent cross-linking of PSA with glycidylmethacrylate (PSA-GMA) which was confirmed with Fourier Transformed Infrared (FTIR) analysis. Incubation of PSA-CaCl(2) and PSA-GMA beads loaded with Alizarin as a model ingredient with trigger enzymes (polygalacturonases or pectate lyases) or bacteria lead to a smoothening of the surface and exposure of Alizarin according to Environmental Scanning Electron Microscopy (ESEM) analysis. Enzyme triggered release of Alizarin was demonstrated for a commercial enzyme preparation from Aspergillus niger and with purified polygalacturonase and pectate lyase from S. rolfsii and B. pumilus, respectively. In contrast to the PSA-CaCl(2) beads, cross-linking (PSA-GMA beads) restricted the release of Alizarin in absence of enzymes. There was a linear relation between release of Alizarin (5-348 μM) and enzyme activity in a range of 0-300 U ml(-1) dosed. In addition to enzymes, both PSA-CaCl(2) and PSA-GMA beads were incubated with Bacillus subtilis and Yersinia entercolitica as model contaminating microorganism. After 72 h, a release between 10 μM and 57 μM Alizarin was detected. For protection of the hydrogels, an enzymatically modified PET membrane was covalently attached onto the surface. This lead to a slower release and improve long term storage stability based on less than 1% release of dye after 21 days. Additionally, this allowed simple detection by visual inspection of the device due to a colour change of the white membrane to orange upon enzyme triggered release of the dye. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. A Near-Infrared Light-Responsive Hybrid Hydrogel Based on UCST Triblock Copolymer and Gold Nanorods

    Directory of Open Access Journals (Sweden)

    Hu Zhang

    2017-06-01

    Full Text Available We report a near-infrared (NIR light-responsive hydrogel that is capable of undergoing the gel to sol transition upon 785 nm light exposure based on a photothermal effect. The new hydrogel design relies on loading gold nanorods (AuNRs in an ABA-type triblock copolymer, namely P(AAm–co–AN–b–PDMA–b–P(AAm–co–AN, where P(AAm–co–AN stands for a random copolymer of acrylamide and acrylonitrile that exhibits an upper critical solution temperature (UCST in aqueous solution and PDMA is water-soluble polydimethylacrylamide. At solution temperature below UCST, the insoluble P(AAm–co–AN blocks lead to formation of hydrogel of flower-like micelles. When the hydrogel is exposed to 785 nm NIR light, the absorption due to the longitudinal surface plasmon resonance of loaded AuNRs generates heat that raises the hydrogel temperature above UCST and, consequently, the gel-to-sol transition. The NIR light-triggered release of a protein loaded in the hydrogel was found to display a switchable fashion.

  19. Waterless Textile Dyeing

    OpenAIRE

    Odabaşoğlu, Hakkı Yasin; AVİNÇ, Osman Ozan; Arzu YAVAŞ

    2013-01-01

    Supercritical carbon dioxide (scCO), having liquid-like densities, hereby provides hydrophobic dyes an advantage on dissolving. Their gas-like low viscosities and diffusion properties can lead to shorter dyeing durations compared to conventional water dyeing process. Supercritical carbon dioxide dyeing, a novel dyeing process, is an anhydrous dyeing and this process involves the use of less energy and chemicals than conventional water dyeing processes resulting in a potential of up to 50% low...

  20. Molecular Exchange in Ordered Diblock Copolymer Micelles

    Science.gov (United States)

    Choi, Soo-Hyung; Lodge, Timothy; Bates, Frank

    2011-03-01

    Previously, molecular exchange between spherical micelles in dilute solution (1 vol% polymer) was investigated using time-resolved small-angle neutron scattering (TR-SANS). As the concentration of spherical micelles formed by the diblock copolymers increases, the micelles begin to overlap and eventually pack onto body-centered cubic (BCC) lattice. In this study, concentrated, ordered micelles (15 vol% polymers) prepared by dispersing isotopically labeled poly(styrene- b -ethylene-alt-propylene) in an isotopic squalane mixture was investigated to understand the micellar concentration dependence of the molecular exchange. Perfectly random mixing of isotopically labeled micelles on the BCC lattice was confirmed by SANS patterns where the interparticle contribution vanishes, resulting in an intensity that directly relates to the exchange kinetics. The measured molecular exchange process for the concentrated, ordered system is qualitatively consistent with the previous observations, but the rate is more than an order of magnitude slower than that for the dilute, disordered system. Infineum(IPrime), MRSEC(NSF), NIST.

  1. MOLECULAR THERMODYNAMICS OF MICELLIZATION: MICELLE SIZE DISTRIBUTIONS AND GEOMETRY TRANSITIONS

    Directory of Open Access Journals (Sweden)

    M. S. Santos

    Full Text Available Abstract Surfactants are amphiphilic molecules that can spontaneously self-assemble in solution, forming structures known as micelles. Variations in temperature, pH, and electrolyte concentration imply changes in the interactions between surfactants and micelle stability conditions, including micelle size distribution and micelle shape. Here, molecular thermodynamics is used to describe and predict conditions of micelle formation in surfactant solutions by directly calculating the minimum Gibbs free energy of the system, corresponding to the most stable condition of the surfactant solution. In order to find it, the proposed methodology takes into account the micelle size distribution and two possible geometries (spherical and spherocylindrical. We propose a numerical optimization methodology where the minimum free energy can be reached faster and in a more reliable way. The proposed models predict the critical micelle concentration well when compared to experimental data, and also predict the effect of salt on micelle geometry transitions.

  2. Efficient deacylation of N-acylimidazoles by functionalized surfactant micelles

    OpenAIRE

    Ihara, Yasuji; Nango, Mamoru; Koga, Joichi; ナンゴ, マモル; 南後, 守

    1989-01-01

    Hydroxylated surfactant micelles are powerful catalysts for the deacylation of N-acylimidazoles under neutral conditions; the deacylation rates of hydrophobia acylimidazoles are accelerated remarkably by functionalized micelles containing three hydroxy groups at the polar head.

  3. Ocular Drug Delivery through pHEMA-Hydrogel Contact Lenses Co-Loaded with Lipophilic Vitamins

    Science.gov (United States)

    Lee, Dasom; Cho, Seungkwon; Park, Hwa Sung; Kwon, Inchan

    2016-01-01

    Ocular drug delivery through hydrogel contact lenses has great potential for the treatment of ocular diseases. Previous studies showed that the loading of lipophilic vitamin E to silicone-hydrogel contact lenses was beneficial in ocular drug delivery. We hypothesized that vitamin E loading to another type of popular hydrogel contact lenses, pHEMA-hydrogel contact lenses, improves ocular drug delivery by increasing the drug loading or the duration of drug release. Loading of vitamin E to pHEMA-hydrogel contact lenses significantly increased the loading of a hydrophilic drug surrogate (Alexa Fluor 488 dye) and two hydrophilic glaucoma drugs (timolol and brimonidine) to the lenses by 37.5%, 19.1%, and 18.7%, respectively. However, the release duration time was not significantly altered. Next, we hypothesized that the lipophilic nature of vitamin E attributes to the enhanced drug loading. Therefore, we investigated the effects of co-loading of another lipophilic vitamin, vitamin A, on drug surrogate delivery. We found out that vitamin A loading also increased the loading of the drug surrogate to pHEMA-hydrogel contact lenses by 30.3%. Similar to vitamin E loading, vitamin A loading did not significantly alter the release duration time of the drug or drug surrogate. PMID:27678247

  4. Ocular Drug Delivery through pHEMA-Hydrogel Contact Lenses Co-Loaded with Lipophilic Vitamins

    Science.gov (United States)

    Lee, Dasom; Cho, Seungkwon; Park, Hwa Sung; Kwon, Inchan

    2016-09-01

    Ocular drug delivery through hydrogel contact lenses has great potential for the treatment of ocular diseases. Previous studies showed that the loading of lipophilic vitamin E to silicone-hydrogel contact lenses was beneficial in ocular drug delivery. We hypothesized that vitamin E loading to another type of popular hydrogel contact lenses, pHEMA-hydrogel contact lenses, improves ocular drug delivery by increasing the drug loading or the duration of drug release. Loading of vitamin E to pHEMA-hydrogel contact lenses significantly increased the loading of a hydrophilic drug surrogate (Alexa Fluor 488 dye) and two hydrophilic glaucoma drugs (timolol and brimonidine) to the lenses by 37.5%, 19.1%, and 18.7%, respectively. However, the release duration time was not significantly altered. Next, we hypothesized that the lipophilic nature of vitamin E attributes to the enhanced drug loading. Therefore, we investigated the effects of co-loading of another lipophilic vitamin, vitamin A, on drug surrogate delivery. We found out that vitamin A loading also increased the loading of the drug surrogate to pHEMA-hydrogel contact lenses by 30.3%. Similar to vitamin E loading, vitamin A loading did not significantly alter the release duration time of the drug or drug surrogate.

  5. Self-Adjustable Adhesion of Polyampholyte Hydrogels.

    Science.gov (United States)

    Roy, Chanchal Kumar; Guo, Hong Lei; Sun, Tao Lin; Ihsan, Abu Bin; Kurokawa, Takayuki; Takahata, Masakazu; Nonoyama, Takayuki; Nakajima, Tasuku; Gong, Jian Ping

    2015-12-02

    Developing nonspecific, fast, and strong adhesives that can glue hydrogels and biotissues substantially promotes the application of hydrogels as biomaterials. Inspired by the ubiquitous adhesiveness of bacteria, it is reported that neutral polyampholyte hydrogels, through their self-adjustable surface, can show rapid, strong, and reversible adhesion to charged hydrogels and biological tissues through the Coulombic interaction.

  6. Mechanism of Molecular Exchange in Copolymer Micelles

    Science.gov (United States)

    Choi, Soo-Hyung; Lodge, Timothy; Bates, Frank

    2010-03-01

    Compared to thermodynamic structure, much less has been known about the kinetics of block copolymer micelles which should underlay the attainment of thermodynamic equilibrium. In this presentation, molecular exchange between spherical micelles formed by isotopically labeled diblock copolymers was investigated using time-resolved small-angle neutron scattering. Two pairs of structurally matched poly(styrene-b-ethylene-alt-propylene) (PS-PEP) were synthesized and dispersed in isotopic mixture of squalane, highly selective to PEP block. Each pair includes polymers with fully deuterated (dPS-PEP) and a normal (hPS-PEP) PS blocks. Temperature dependence of the micelle exchange rate R(t) is consistent with melt dynamics for the core polymer. Furthermore, R(t) is significantly sensitive to the core block length N due to the thermodynamic penalty associated with ejecting a core block into the solvent. This hypersensitivity, combined with modest polydispersity in N, leads to an approximately logarithmic decay in R(t).

  7. Coal desulfurization through reverse micelle biocatalysis process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K.; Yen, T.F.

    1988-01-01

    A novel bioprocess using micelle biocatalysis has been attempted to minimize several disadvantages of conventional microbial coal desulfurization scale-up processes. The reverse micelle biocatalysis process consists of a water-immiscible organic medium, a surfactant, an aqueous phase and sulfur-oxidizing bacteria or enzymes. This process has been successful for removing sulfur from bituminous coal (Illinois coal 5). The preliminary results showed that coal desulfurization through the use of cell-free enzyme extracts of Thiobacillus ferrooxidans ATCC 19859 was better than that of bacteria itself. The use of enzymes has shown potential for commercial coal desulfurization process as well. This same process is being applied to the thermophillic bacteria Sulfolobus acidocaldarius ATCC 33909. The implications of these experimental results are discussed, including a hypothetical mechanism using reverse micelle biocatalytical process for coal desulfurization.

  8. Stretchable Hydrogel Electronics and Devices.

    Science.gov (United States)

    Lin, Shaoting; Yuk, Hyunwoo; Zhang, Teng; Parada, German Alberto; Koo, Hyunwoo; Yu, Cunjiang; Zhao, Xuanhe

    2016-06-01

    Stretchable hydrogel electronics and devices are designed by integrating stretchable conductors, functional chips, drug-delivery channels, and reservoirs into stretchable, robust, and biocompatible hydrogel matrices. Novel applications include a smart wound dressing capable of sensing the temperatures of various locations on the skin, delivering different drugs to these locations, and subsequently maintaining sustained release of drugs.

  9. Hydrogels with micellar hydrophobic (nanodomains

    Directory of Open Access Journals (Sweden)

    Miloslav ePekař

    2015-01-01

    Full Text Available Hydrogels containing hydrophobic domains or nanodomains, especially of the micellar type, are reviewed. Examples of the reasons for introducing hydrophobic domains into hydrophilic gels are given; typology of these materials is introduced. Synthesis routes are exemplified and properties of a variety of such hydrogels in relation with their intended applications are described. Future research needs are identified briefly.

  10. Salt-induced release of lipase from polyelectrolyte complex micelles

    NARCIS (Netherlands)

    Lindhoud, Saskia; de Vries, Renko; Schweins, Ralf; Stuart, Martien A. Cohen; Norde, Willem

    2009-01-01

    With the aim to gain insight into the possible applicability of protein-filled polyelectrolyte complex micelles under physiological salt conditions, we studied the behavior of these micelles as a function of salt concentration. The micelles form by electrostatically driven co-assembly from strong ca

  11. Designed biodegradable hydrogel structures prepared by stereolithography using poly(ethylene glycol)/poly(D,L-lactide)-based resins

    NARCIS (Netherlands)

    Seck, Tetsu M.; Melchels, Ferry P. W.; Feijen, Jan; Grijpma, Dirk W.

    2010-01-01

    Designed three-dimensional biodegradable poly(ethylene glycol)/poly(D,L-lactide) hydrogel structures were prepared for the first time by stereolithography at high resolutions. A photo-polymerisable aqueous resin comprising PDLLA-PEG-PDLLA-based macromer, visible light photo-initiator, dye and inhibi

  12. MESO—STRUCTURED POLYMERIC HYDROGELS

    Institute of Scientific and Technical Information of China (English)

    Zhen-zhongYang; Jian-huaRong; DanLi

    2003-01-01

    Meso-structured(opal and inverse opal) polymeric hydrogels of varied morphology and composition were prepared by using two methods:post-modification of the template-synthesized structured polymers and templatepolymerization of functional monomers.A polyacrylic acid based inverse opal hydrogel was chosen to demonstrate its fast pH response by changing color,which is important in designing tunable photonic crystals.Template effects of the hydrogels on controlling structure of the template-synthesized inorganic materials were discussed.The catalytic effect of acid groups in the templates was emphasized for a preferential formation of TiO2 in the region containing acid groups,which allowed duplicating inorganic colloidal crystals from colloidal crystal hydrogels (or macroporous products from macroporous hydrogels) via one step duplication.

  13. MESO-STRUCTURED POLYMERIC HYDROGELS

    Institute of Scientific and Technical Information of China (English)

    Zhen-zhong Yang; Jian-hua Rong; Dan Li

    2003-01-01

    Meso-structured (opal and inverse opal) polymeric hydrogels of varied morphology and composition were prepared by using two methods: post-modification of the template-synthesized structured polymers and templatepolymerization of functional monomers. A polyacrylic acid based inverse opal hydrogel was chosen to demonstrate its fast pH response by changing color, which is important in designing tunable photonic crystals. Template effects of the hydrogels on controlling structure of the template-synthesized inorganic materials were discussed. The catalytic effect of acid groups inthe templates was emphasized for a preferential formation of TiO2 in the region containing acid groups, which allowed duplicating inorganic colloidal crystals from colloidal crystal hydrogels (or macroporous products from macroporous hydrogels) via one step duplication.

  14. Stability of casein micelles in milk

    Science.gov (United States)

    Tuinier, R.; de Kruif, C. G.

    2002-07-01

    Casein micelles in milk are proteinaceous colloidal particles and are essential for the production of flocculated and gelled products such as yogurt, cheese, and ice-cream. The colloidal stability of casein micelles is described here by a calculation of the pair potential, containing the essential contributions of brush repulsion, electrostatic repulsion, and van der Waals attraction. The parameters required are taken from the literature. The results are expressed by the second osmotic virial coefficient and are quite consistent with experimental findings. It appears that the stability is mainly attributable to a steric layer of κ-casein, which can be described as a salted polyelectrolyte brush.

  15. Statistical crystallography of surface micelle spacing

    Science.gov (United States)

    Noever, David A.

    1992-01-01

    The aggregation of the recently reported surface micelles of block polyelectrolytes is analyzed using techniques of statistical crystallography. A polygonal lattice (Voronoi mosaic) connects center-to-center points, yielding statistical agreement with crystallographic predictions; Aboav-Weaire's law and Lewis's law are verified. This protocol supplements the standard analysis of surface micelles leading to aggregation number determination and, when compared to numerical simulations, allows further insight into the random partitioning of surface films. In particular, agreement with Lewis's law has been linked to the geometric packing requirements of filling two-dimensional space which compete with (or balance) physical forces such as interfacial tension, electrostatic repulsion, and van der Waals attraction.

  16. Polymeric micelles as carriers of diagnostic agents.

    Science.gov (United States)

    Trubetskoy

    1999-04-01

    This review deals with diagnostic applications of polymeric micelles composed of amphiphilic block-copolymers. In aqueous solutions these polymers spontaneously form particles with diameter 20-100 nm. A variety of diagnostic moieties can be incorporated covalently or non-covalently into the particulates with high loads. Resulting particles can be used as particulate agents for diagnostic imaging using three major imaging modalities: gamma-scintigraphy, magnetic resonance imaging and computed tomography. The use of polyethyleneoxide-diacyllipid micelles loaded with chelated (111)In/Gd(3+) as well as iodine-containing amphiphilic copolymer in percutaneous lymphography and blood pool/liver imaging are discussed as specific examples.

  17. Distinct CPT-induced deaths in lung cancer cells caused by clathrin-mediated internalization of CP micelles

    Science.gov (United States)

    Liu, Yu-Sheng; Cheng, Ru-You; Lo, Yu-Lun; Hsu, Chin; Chen, Su-Hwei; Chiu, Chien-Chih; Wang, Li-Fang

    2016-02-01

    We previously synthesized a chondroitin sulfate-graft-poly(ε-caprolactone) copolymer (H-CP) with a high content of poly(ε-caprolactone) (18.7 mol%), which self-assembled in water into a rod-like micelle to encapsulate hydrophobic camptothecin (CPT) in the core (micelle/CPT) for tumor-targeted drug delivery. As a result of the recognition of the micelle by CD44, the micelle/CPT entered CRL-5802 cells efficiently and released CPT efficaciously, resulting in higher tumor suppression than commercial CPT-11. In this study, H1299 cells were found to have a higher CD44 expression than CRL-5802 cells. However, the lower CD44-expressing CRL-5802 cells had a higher percentage of cell death and higher cellular uptake of the micelle/CPT than the higher CD44-expressing H1299 cells. Examination of the internalization pathway of the micelle/CPT in the presence of different endocytic chemical inhibitors showed that the CRL-5802 cells involved clathrin-mediated endocytosis, which was not found in the H1299 cells. Analysis of the cell cycle of the two cell lines exposed to the micelle/CPT revealed that the CRL-5802 cells arrested mainly in the S phase and the H1299 cells arrested mainly in the G2-M phase. A consistent result was also found in the evaluation of γ-H2AX expression, which was about three-fold higher in the CRL-5802 cells than in the H1299 cells. A near-infrared dye, IR780, was encapsulated into the micelle to observe the in vivo biodistribution of the micelle/IR780 in tumor-bearing mice. The CRL-5802 tumor showed a higher fluorescence intensity than the H1299 tumor at any tracing time after 1 h. Thus we tentatively concluded that CRL-5802 cells utilized the clathrin-mediated internalization pathway and arrested in the S phase on exposure to the micelle/CPT; all are possible reasons for the better therapeutic outcome in CRL-5802 cells than in H1299 cells.We previously synthesized a chondroitin sulfate-graft-poly(ε-caprolactone) copolymer (H-CP) with a high content of

  18. Hair dye poisoning

    Science.gov (United States)

    Hair tint poisoning ... Different types of hair dye contain different harmful ingredients. The harmful ingredients in permanent dyes are: Naphthylamine Other aromatic amino compounds Phenylenediamines Toluene ...

  19. Alginate/PEO-PPO-PEO composite hydrogels with thermally-active plasticity.

    Science.gov (United States)

    White, Joseph C; Saffer, Erika M; Bhatia, Surita R

    2013-12-09

    Stimuli-responsive hydrogels with high strength and toughness have received significant interest in recent years. Here, we report thermally active composite hydrogels comprising alginate and one of two poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers. Temperature-sensitive structural and mechanical changes are probed using calorimetry, neutron scattering, shear rheology, unconfined compression, and fracture. Below the lower gelation temperature, LGT, the mechanical properties are dominated by alginate. As the LGT is reached, the contribution of PEO-PPO-PEO to the mechanical properties is activated, resulting in order-of-magnitude increases in elastic modulus. Under compression, we show the evolution of plasticity for the composite hydrogels as the LGT is approached and surpassed, resulting in dramatic increases in fracture stress compared to neat alginate hydrogels. Plasticity was observed above the LGT and may be attributed to restructuring from the sliding of packed micelles and strain-hardening due to stress concentration on alginate cross-links and junction zones, ultimately leading to fracture.

  20. Spectroscopic studies of interaction of Safranine T with nonionic micelles and mixed micelles.

    Science.gov (United States)

    Chatterjee, Sujan; Bhattacharya, Subhash Chandra

    2006-05-15

    The visible spectra of Safranine T (ST) in micellar solution of Brij 58, Tween 20 and Tween 40 and mixed micellar solution of Brij 58/Tween 20 and Brij 58/Tween 40 indicate formation of 1:1 charge transfer (CT) complex between acceptor ST and donor nonionic micelles and mixed micelles. The experimental CT transition energies are well correlated (through Mulliken's equation) with the vertical ionization potential of the donors. The solvent parameters, i.e. the intramolecular charge transfer energy ET(30) have been determined from the Stokes spectral shift. Variations of ionization potential and micropolarity in the mixed micellar region have been investigated as a function of surfactant composition and the obtained results in mixed micellar medium has been compared to the normal micelles. The critical micelle concentration (CMC) values determined at various surfactant compositions are lower than the ideal values indicating a synergistic interaction. The interaction parameter (beta) and micellar stability has been calculated using regular solution theory.

  1. Micelle depletion-induced vs. micelle-mediated aggregation in nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ray, D., E-mail: debes.phys@gmail.com; Aswal, V. K. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2015-06-24

    The phase behavior anionic silica nanoparticle (Ludox LS30) with non-ionic surfactants decaethylene glycol monododecylether (C12E10) and cationic dodecyltrimethyl ammonium bromide (DTAB) in aqueous electrolyte solution has been studied by small-angle neutron scattering (SANS). The measurements have been carried out for fixed concentrations of nanoparticle (1 wt%), surfactants (1 wt%) and electrolyte (0.1 M NaCl). Each of these nanoparticle–surfactant systems has been examined for different contrast conditions where individual components (nanoparticle or surfactant) are made visible. It is observed that the nanoparticle-micelle system in both the cases lead to the aggregation of nanoparticles. The aggregation is found to be micelle depletion-induced for C12E10 whereas micelle-mediated aggregation for DTAB. Interestingly, it is also found that phase behavior of mixed surfactant (C12E10 + DTAB) system is similar to that of C12E10 (unlike DTAB) micelles with nanoparticles.

  2. Applications of micelle enhancement in luminescence-based analysis.

    Science.gov (United States)

    Alarfaj, Nawal A; El-Tohamy, Maha F

    2015-02-01

    Micelles are self-assembled aggregates that arrange themselves into spheres in aqueous media. When the surfactant concentration reaches the critical micelle concentration, extensive aggregation of the surfactant monomers occurs to form micelles. A micelle has both a hydrophilic and a hydrophobic part. This allows them to form a spherical shape and for their glycolipid and phospholipid components to form lipid bilayers. The importance of micelles is increasing because of their wide analytical applications. Recently, colloidal carrier systems have received much attention in the field of analytical chemistry, especially in luminescence enhancement applications.

  3. Local delivery of fluorescent dye for fiber-optics confocal microscopy of the living heart.

    Science.gov (United States)

    Huang, Chao; Kaza, Aditya K; Hitchcock, Robert W; Sachse, Frank B

    2014-01-01

    Fiber-optics confocal microscopy (FCM) is an emerging imaging technology with various applications in basic research and clinical diagnosis. FCM allows for real-time in situ microscopy of tissue at sub-cellular scale. Recently FCM has been investigated for cardiac imaging, in particular, for discrimination of cardiac tissue during pediatric open-heart surgery. FCM relies on fluorescent dyes. The current clinical approach of dye delivery is based on systemic injection, which is associated with high dye consumption, and adverse clinical events. In this study, we investigated approaches for local dye delivery during FCM imaging based on dye carriers attached to the imaging probe. Using three-dimensional confocal microscopy, automated bench tests, and FCM imaging we quantitatively characterized dye release of carriers composed of open-pore foam only and foam loaded with agarose hydrogel. In addition, we compared local dye delivery with a model of systemic dye delivery in the isolated perfused rodent heart. We measured the signal-to-noise ratio (SNR) of images acquired in various regions of the heart. Our evaluations showed that foam-agarose dye carriers exhibited a prolonged dye release vs. foam-only carriers. Foam-agarose dye carriers allowed reliable imaging of 5-9 lines, which is comparable to 4-8 min of continuous dye release. Our study in the living heart revealed that the SNR of FCM images using local and systemic dye delivery is not different. However, we observed differences in the imaged tissue microstructure with the two approaches. Structural features characteristic of microvasculature were solely observed for systemic dye delivery. Our findings suggest that local dye delivery approach for FCM imaging constitutes an important alternative to systemic dye delivery. We suggest that the approach for local dye delivery will facilitate clinical translation of FCM, for instance, for FCM imaging during pediatric heart surgery.

  4. Local Delivery of Fluorescent Dye For Fiber-Optics Confocal Microscopy of the Living Heart

    Directory of Open Access Journals (Sweden)

    Chao eHuang

    2014-09-01

    Full Text Available Fiber-optics confocal microscopy (FCM is an emerging imaging technology with various applications in basic research and clinical diagnosis. FCM allows for real-time in situ microscopy of tissue at sub-cellular scale. Recently FCM has been investigated for cardiac imaging, in particular, for discrimination of cardiac tissue during pediatric open-heart surgery. FCM relies on fluorescent dyes. The current clinical approach of dye delivery is based on systemic injection, which is associated with high dye consumption and adverse clinical events. In this study, we investigated approaches for local dye delivery during FCM imaging based on dye carriers attached to the imaging probe. Using three-dimensional confocal microscopy, automated bench tests, and FCM imaging we quantitatively characterized dye release of carriers composed of open-pore foam only and foam loaded with agarose hydrogel. In addition, we compared local dye delivery with a model of systemic dye delivery in the isolated perfused rodent heart. We measured the signal-to-noise ratio of images acquired in various regions of the heart. Our evaluations showed that foam-agarose dye carriers exhibited a prolonged dye release versus foam-only carriers. Foam-agarose dye carriers allowed reliable imaging of 5-9 lines, which is comparable to 4-8 min of continuous dye release. Our study in the living heart revealed that the SNR of FCM images using local and systemic dye delivery is not different. However, we observed differences in the imaged tissue microstructure with the two approaches. Structural features characteristic of microvasculature were solely observed for systemic dye delivery. Our findings suggest that local dye delivery approach for FCM imaging constitutes an important alternative to systemic dye delivery. We suggest that the approach for local dye delivery will facilitate clinical translation of FCM, for instance, for FCM imaging during pediatric heart surgery.

  5. Monomeric α-synuclein binds Congo Red micelles in a disordered manner.

    Science.gov (United States)

    Maltsev, Alexander S; Grishaev, Alexander; Bax, Ad

    2012-01-17

    The histological dye Congo Red (CR) previously has been shown to inhibit α-synuclein (aS) fibrillation, but the mode of this inhibition remained unclear. Because of favorable exchange kinetics, interaction between CR and aS lends itself to a detailed nuclear magnetic resonance study, and relaxation dispersion measurements yield the bound fraction and time scales for the interaction of aS with CR. We find that at pH 6, CR exists as a micelle, and at a CR:aS molar ratio of ~1, only a small fraction of aS (~2%) is bound to these micelles. Rapid exchange (k(ex) ~ 3000 s(-1)) between the free and CR-bound states broadens and strongly attenuates resonances of aS by two processes: a magnetic field-dependent contribution, caused by the chemical shift difference between the two states, and a nearly field-independent contribution caused by slower tumbling of aS bound to the CR micelle. The salt dependence of the interaction suggests a predominantly electrostatic mechanism for the 60 N-terminal residues, while the weaker interaction between residues 61-100 and CR is mostly hydrophobic. Chemical shift and transferred NOE data indicate that aS becomes slightly more helical but remains largely disordered when bound to CR. Results indicate that inhibition of fibril formation does not result from binding of CR to free aS and, therefore, must result from interaction of aS fibrils or protofibrils with CR micelles.

  6. Molecular Exchange Dynamics in Block Copolymer Micelles

    Science.gov (United States)

    Bates, Frank; Lu, Jie; Choi, Soohyung; Lodge, Timothy

    2012-02-01

    Poly(styrene-b-ethylene propylene) (PS-PEP) diblock copolymers were mixed with squalane (C30H62) at 1% by weight resulting in the formation of spherical micelles. The structure and dynamics of molecular exchange were characterized by synchrotron small-angle x-ray scattering (SAXS) and time resolved small-angle neutron scattering (TR-SANS), respectively, between 100 C and 160 C. TR-SANS measurements were performed with solutions initially containing deuterium labeled micelle cores and normal cores dispersed in a contrast matched squalane. Monitoring the reduction in scattering intensity as a function of time at various temperatures revealed molecular exchange dynamics highly sensitive to the core molecular weight and molecular weight distribution. Time-temperature superposition of data acquired at different temperatures produced a single master curve for all the mixtures. Experiments conducted with isotopically labeled micelle cores, each formed from two different but relatively mondisperse PS blocks, confirmed a simple dynamical model based on first order kinetics and core Rouse single chain relaxation. These findings demonstrate a dramatic transition to nonergodicity with increasing micelle core molecular weight and confirm the origins of the logarithmic exchange kinetics in such systems.

  7. Chain exchange in block copolymer micelles

    Science.gov (United States)

    Lu, Jie; Bates, Frank; Lodge, Timothy

    2014-03-01

    Block copolymer micelles are aggregates formed by self-assembly of amphiphilic copolymers dispersed in a selective solvent, driven by unfavorable interactions between the solvent and the core-forming block. Due to the relatively long chains being subject to additional thermodynamic and dynamic constraints (e.g., entanglements, crystallinity, vitrification), block copolymer micelles exhibit significantly slower equilibration kinetics than small molecule surfactants. As a result, details of the mechanism(s) of equilibration in block copolymer micelles remain unclear. This present works focuses on the chain exchange kinetics of poly(styrene-b-ethylenepropylene) block copolymers in squalane (C30H62) using time-resolved small angle neutron scattering (TR-SANS). A mixture of h-squalane and d-squalane is chosen so that it contrast matches a mixed 50/50 h/d polystyrene micelle core. When the temperature is appropriate and isotopically labeled chains undergo mixing, the mean core contrast with respect to the solvent decreases, and the scattering intensity is therefore reduced. This strategy allows direct probing of chain exchange rate from the time dependent scattering intensity I(q, t).

  8. POLYMER MICELLE INTERACTIONS - PHYSICAL ORGANIC ASPECTS

    NARCIS (Netherlands)

    BRACKMAN, JC; ENGBERTS, JBFN

    1993-01-01

    This review presents a summary of attempts to characterize the morphology of the complexes formed between ionic and non-ionic surfactants and water-soluble polymers. It is now generally accepted that complex formation involves the binding of micelles to the macromolecule. This binding process modifi

  9. SANS analysis of aqueous ionic perfluoropolyether micelles

    CERN Document Server

    Gambi, C M C; Chittofrati, A; Pieri, R; Baglioni, P; Teixeira, J

    2002-01-01

    Preliminary SANS results of ionic chlorine terminated perfluoropolyether micelles in water are given. The experimental spectra have been analyzed by a two-shell ellipsoidal model for the micellar form factor and a screened Coulombic plus hard-sphere repulsion potential for the structure factor. (orig.)

  10. On the composition fluctuations of reverse micelles.

    Science.gov (United States)

    Tovstun, Sergey A; Razumov, Vladimir F

    2010-11-15

    The polydispersity of the reverse micelles is determined mainly by the fluctuations of their composition. The composition of the reverse micelle is a two-dimensional random variable whose components are the numbers of water (i) and surfactant (j) molecules. In this study the fluctuations of the composition of the reverse micelles are considered in the Gaussian approximation. It is shown that the standard deviation of the quantity w=i/j may be calculated from the dependence of the water vapor pressure above the microemulsion on the molar ratio W=[water]/[surfactant]. The estimation based on the literature data for microemulsion system sodium bis(2-ethylhexyl)sulfosuccinate/water/isooctane at 37°C in the range W=0-18 has shown that the relative standard deviation of the quantity w is about 10%. It is shown that the value of the composition fluctuations is related to the dependence of average composition on the concentration of reverse micelles at constant parameter W.

  11. Acid Hydrolysis of Bromazepam Catalyzed by Micelles, Reverse Micelles, and Microemulsions

    Directory of Open Access Journals (Sweden)

    Ferdousi Begum

    2015-01-01

    Full Text Available Kinetics of the acid hydrolysis of bromazepam (Bz has been investigated in micelles, reverse micelles, and microemulcions of cetyltrimethylammonium bromide (CTAB by spectrophotometric method. The rate of the acid hydrolysis of Bz was found to be enhanced both below and above the critical micelle concentration (CMC of CTAB in aqueous solution. The pseudo-first-order rate constant (k′ shows an initial decrease for both low and high H+ concentrations. With further increase in [CTAB], at low [H+], the k′ attains an almost constant value, while, at high [H+], the k′ passes through a maximum and then decreases. The kinetic data for catalysis by micelles of CTAB was interpreted with the pseudophase ion exchange (PIE model. In CTAB/cyclohexane/1-butanol/water microemulsions, as the water to surfactant ratio (wo increases, the physicochemical properties and droplet sizes of microemulsions significantly change and distinct changes in reaction environment can be marked. The rate of the hydrolysis reaction exhibits excellent correlation with the physicochemical properties and droplet sizes of the microemulsions and reverse micelles of CTAB. At [H+] = 0.001 M, in reverse micelles and microemulsions of CTAB, the k′ of the acid hydrolysis of Bz decreases sharply followed by a slight increase with increasing wo.

  12. Hydrogel wound dressing by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshii, Fumio [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-03-01

    Water soluble polymers such as polyethyleneoxide (PEO), polyvinyl alcohol (PVA) were irradiated in solid and molten states as well as in aqueous solution in order to synthesize a hydrogel. PEO undergoes crosslinking at all phases by radiation initiation. Among these phases, the radiation in the aqueous solution requires the lowest dose for crosslinking due to the contribution of OH radical created in radiolysis of water. The hydrogel prepared by irradiation in aqueous solution was applied to a dressing for healing of wound. In order to evaluate the healing effect of the PEO hydrogel dressing, wounds formed on the back of marmots were covered by the hydrogel. The healing under the wet environment of the hydrogel dressing had three advantages, compared with that of gauze dressing, which gives a dry environment: (1) enhancement of healing rate, (2) facilitation for changing the dressing, i.e. the hydrogel can be peeled off without any damage to the regenerated skin surface, and (3) hydrogel dressing material does not remain stuck on the wound. (author)

  13. Syneresis in agar hydrogels.

    Science.gov (United States)

    Boral, Shilpi; Saxena, Anita; Bohidar, H B

    2010-03-01

    Agar hydrogels exhibit syneresis which creates internal osmotic stress on the physical network. It was observed that such a stress gives rise to characteristic pulsating modes (breathing modes). Experiments carried over a period of 60-day revealed that the network deformations grew monotonously when the solvent released by syneresis was removed periodically from gel surface. However, when the solvent was not withdrawn, the gel exhibited very slowly relaxing breathing modes. The swelling-deswelling dynamics has been discussed in the generalized framework of a dissipative damped oscillator.

  14. Casein micelles and their internal structure

    Energy Technology Data Exchange (ETDEWEB)

    De Kruif, Cornelis G [ORNL; Huppertz, Thom [NIZO Food Research; Urban, Volker S [ORNL; Petukhov, Andrei V [Van ' t Hoff laboratory for Physical and Colloid Chemistry, Utrecht University, The Netherlands

    2012-01-01

    The internal structure of casein micelles was studied by calculating the small-angle neutron and X-ray scattering and static light scattering spectrum (SANS, SAXS, SLS) as a function of the scattering contrast and composition. We predicted experimental SANS, SAXS, SLS spectra self consistently using independently determined parameters for composition size, polydispersity, density and voluminosity. The internal structure of the casein micelles, i.e. how the various components are distributed within the casein micelle, was modeled according to three different models advocated in the literature; i.e. the classical sub-micelle model, the nanocluster model and the dual binding model. In this paper we present the essential features of these models and combine new and old experimental SANS, SAXS, SLS and DLS scattering data with new calculations that predict the spectra. Further evidence on micellar substructure was obtained by internally cross linking the casein micelles using transglutaminase, which led to casein nanogel particles. In contrast to native casein micelles, the nanogel particles were stable in 6 M urea and after sequestering the calcium using trisodium citrate. The changed scattering properties were again predicted self consistently. An important result is that the radius of gyration is independent of contrast, indicating that the mass distribution within a casein micelle is homogeneous. Experimental contrast is predicted quite well leading to a match point at a D{sub 2}O volume fraction of 0.41 ratio in SANS. Using SANS and SAXS model calculations it is concluded that only the nanocluster model is capable of accounting for the experimental scattering contrast variation data. All features and trends are predicted self consistently, among which the 'famous' shoulder at a wave vector value Q = 0.35 nm{sup -1}. In the nanocluster model, the casein micelle is considered as a (homogeneous) matrix of caseins in which the colloidal calcium phosphate (CCP

  15. Gelation and micellization behaviors of pluronic(®) F127 hydrogel containing poly(isobutylcyanoacrylate) nanoparticles specifically designed for mucosal application.

    Science.gov (United States)

    Pradines, Bénédicte; Djabourov, Madeleine; Vauthier, Christine; Loiseau, Philippe M; Ponchel, Gilles; Bouchemal, Kawthar

    2015-11-01

    The aim of this investigation is to combine the advantages of pluronic(®) F127 hydrogels and nanoparticles composed of poly(isobutylcyanoacrylate) (PIBCA) core coated with a mixture of chitosan and thiolated chitosan to design novel multifunctional formulation for mucosal application. Nanoparticles offer the advantage of being mucoadhesive while pluronic(®) F127 hydrogel allowed prolonged contact time onto mucosal surfaces. This work highlights an unprecedented comprehensive study on the effect of nanoparticles on gelation and micellization behaviors of pluronic(®) F127 using rheology and micro-calorimetry experiments. Results showed that presence of nanoparticles induced (i) smaller crystal peak of F127, (ii) a decrease of the enthalpy of F127 micellization and (iii) a non-reversibility of micelle formation (during heating ramp) and micelle melting (during cooling ramp). Together, these findings suggest that a part of F127 was not able to associate into micelles and the formation of mixed micelles containing F127 unimers and PIBCA/(chitosan/thiolated chitosan) copolymer and/or PIBCA homopolymer was suspected. The interaction of F127 unimers with nanoparticles resulted from their physical de-structuration as revealed by nanoparticle size measurement. In addition, we found that short polymerization duration of one hour induced more pronounced nanoparticle de-structuration. Twenty-four hour-polymerization of isobutylcyanoacrylate in the presence of chitosan and thiolated chitosan led to more stable nanoparticles when mixed with pluronic(®) F127.

  16. Synthetically simple, highly resilient hydrogels.

    Science.gov (United States)

    Cui, Jun; Lackey, Melissa A; Madkour, Ahmad E; Saffer, Erika M; Griffin, David M; Bhatia, Surita R; Crosby, Alfred J; Tew, Gregory N

    2012-03-12

    Highly resilient synthetic hydrogels were synthesized by using the efficient thiol-norbornene chemistry to cross-link hydrophilic poly(ethylene glycol) (PEG) and hydrophobic polydimethylsiloxane (PDMS) polymer chains. The swelling and mechanical properties of the hydrogels were controlled by the relative amounts of PEG and PDMS. The fracture toughness (G(c)) was increased to 80 J/m(2) as the water content of the hydrogel decreased from 95% to 82%. In addition, the mechanical energy storage efficiency (resilience) was more than 97% at strains up to 300%. This is comparable with one of the most resilient materials known: natural resilin, an elastic protein found in many insects, such as in the tendons of fleas and the wings of dragonflies. The high resilience of these hydrogels can be attributed to the well-defined network structure provided by the versatile chemistry, low cross-link density, and lack of secondary structure in the polymer chains.

  17. Preparation and Evaluation of Inhalable Itraconazole Chitosan Based Polymeric Micelles

    Directory of Open Access Journals (Sweden)

    Esmaeil Moazeni

    2012-12-01

    Full Text Available Background: This study evaluated the potential of chitosan based polymeric micelles as a nanocarrier system for pulmonary delivery of itraconazole (ITRA.Methods: Hydrophobically modified chitosan were synthesized by conjugation of stearic acid to the hydrophilic depolymerized chitosan. FTIR and 1HNMR were used to prove the chemical structure and physical properties of the depolymerized and the stearic acid grafted chitosan. ITRA was entrapped into the micelles and physicochemical properties of the micelles were investigated. Fluorescence spectroscopy, dynamic laser light scattering andtransmission electron microscopy were used to characterize the physicochemical properties of the prepared micelles. The in vitro pulmonary profile of polymeric micelles was studied by an air-jet nebulizer connected to a twin stage impinger.Results: The polymeric micelles prepared in this study could entrap up to 43.2±2.27 μg of ITRA per milliliter. All micelles showed mean diameter between 120–200 nm. The critical micelle concentration of the stearic acid grafted chitosan was found to be 1.58×10-2 mg/ml. The nebulization efficiency was up to 89% and the fine particle fraction (FPF varied from 38% to 47%. The micelles had enough stability to remain encapsulation of the drug during nebulization process.Conclusions: In vitro data showed that stearic acid grafted chitosan based polymeric micelles has a potential to be used as nanocarriers for delivery of itraconazole through inhalation.

  18. Cytocompatible cellulose hydrogels containing trace lignin.

    Science.gov (United States)

    Nakasone, Kazuki; Kobayashi, Takaomi

    2016-07-01

    Sugarcane bagasse was used as a cellulose resource to prepare transparent and flexible cellulose hydrogel films. On the purification process from bagasse to cellulose, the effect of lignin residues in the cellulose was examined for the properties and cytocompatibility of the resultant hydrogel films. The cellulose was dissolved in lithium chloride/N,N-dimethylacetamide solution and converted to hydrogel films by phase inversion. In the purification process, sodium hydroxide (NaOH) treatment time was changed from 1 to 12h. This resulted in cellulose hydrogel films having small amounts of lignin from 1.62 to 0.68%. The remaining lignin greatly affected hydrogel properties. Water content of the hydrogel films was increased from 1153 to 1525% with a decrease of lignin content. Moreover, lower lignin content caused weakening of tensile strength from 0.80 to 0.43N/mm(2) and elongation from 45.2 to 26.5%. Also, similar tendency was observed in viscoelastic behavior of the cellulose hydrogel films. Evidence was shown that the lignin residue was effective for the high strength of the hydrogel films. In addition, scanning probe microscopy in the morphological observation was suggested that the trace lignin in the cellulose hydrogel affected the cellulose fiber aggregation in the hydrogel network. The trace of lignin in the hydrogels also influenced fibroblast cell culture on the hydrogel films. The hydrogel film containing 1.68% lignin showed better fibroblast compatibility as compared to cell culture polystyrene dish used as reference.

  19. Energy conversion in polyelectrolyte hydrogels

    Science.gov (United States)

    Olvera de La Cruz, Monica; Erbas, Aykut; Olvera de la Cruz Team

    Energy conversion and storage have been an active field of research in nanotechnology parallel to recent interests towards renewable energy. Polyelectrolyte (PE) hydrogels have attracted considerable attention in this field due to their mechanical flexibility and stimuli-responsive properties. Ideally, when a hydrogel is deformed, applied mechanical work can be converted into electrostatic, elastic and steric-interaction energies. In this talk, we discuss the results of our extensive molecular dynamics simulations of PE hydrogels. We demonstrate that, on deformation, hydrogels adjust their deformed state predominantly by altering electrostatic interactions between their charged groups rather than excluded-volume and bond energies. This is due to the hydrogel's inherent tendency to preserve electro-neutrality in its interior, in combination with correlations imposed by backbone charges. Our findings are valid for a wide range of compression ratios and ionic strengths. The electrostatic-energy alterations that we observe in our MD simulations may induce pH or redox-potential changes inside the hydrogels. The resulting energetic difference can be harvested, for instance, analogously to a Carnot engine, or facilitated for sensor applications. Center for Bio-inspired Energy Science (CBES).

  20. On the stability and morphology of complex coacervate core micelles: from spherical to wormlike micelles.

    Science.gov (United States)

    van der Kooij, Hanne M; Spruijt, Evan; Voets, Ilja K; Fokkink, Remco; Cohen Stuart, Martien A; van der Gucht, Jasper

    2012-10-01

    We present a systematic study of the stability and morphology of complex coacervate core micelles (C3Ms) formed from poly(acrylic acid) (PAA) and poly(N-methyl-2-vinylpyridinium)-b-poly(ethylene oxide) (PM2VP-b-PEO). We use polarized and depolarized dynamic and static light scattering, combined with small-angle X-ray scattering, to investigate how the polymer chain length and salt concentration affect the stability, size, and shape of these micelles. We show that C3Ms are formed in aqueous solution below a critical salt concentration, which increases considerably with increasing PAA and PM2VP length and levels off for long chains. This trend is in good agreement with a mean-field model of polyelectrolyte complexation based on the Voorn-Overbeek theory. In addition, we find that salt induces morphological changes in C3Ms when the PAA homopolymer is sufficiently short: from spherical micelles with a diameter of several tens of nanometers at low salt concentration to wormlike micelles with a contour length of several hundreds of nanometers just before the critical salt concentration. By contrast, C3Ms of long PAA homopolymers remain spherical upon addition of salt and shrink slightly. A critical review of existing literature on other C3Ms reveals that the transition from spherical to wormlike micelles is probably a general phenomenon, which can be rationalized in terms of a classical packing parameter for amphiphiles.

  1. Magneto-fluorescent hybrid of dye and SPION with ordered and radially distributed porous structures

    Science.gov (United States)

    Gogoi, Madhulekha; Deb, Pritam

    2014-04-01

    We have reported the development of a silica based magneto-fluorescent hybrid of a newly synthesized dye and superparamagnetic iron oxide nanoparticles with ordered and radially distributed porous structure. The dye is synthesized by a novel yet simple synthetic approach based on Michael addition between dimer of glutaraldehyde and oleylamine molecule. The surfactant used for phase transformation of the dye from organic to aqueous phase, also acts as a structure directing agent for the porous structure evolution of the hybrid with radial distribution. The evolution of the radially distributed pores in the hybrids can be attributed to the formation of rod-like micelles containing nanoparticles, for concentration of micelles greater than critical micelle concentration. A novel water extraction method is applied to remove the surfactants resulting in the characteristic porous structure of the hybrid. Adsorption isotherm analysis confirms the porous nature of the hybrids with pore diameter ∼2.4 nm. A distinct modification in optical and magnetic property is observed due to interaction of the dye and SPION within the silica matrix. The integration of multiple structural components in the so developed hybrid nanosystem results into a potential agent for multifunctional biomedical application.

  2. Smart wormlike micelles design, characteristics and applications

    CERN Document Server

    Feng, Yujun; Dreiss, Cécile A

    2015-01-01

    This Brief provides an up-to-date overview of smart surfactants and describes a broad spectrum of triggers that induce the formation of wormlike micelles or reversibly tune the morphology of surfactant aggregates from wormlike micelles to another state, or vice versa. Combining the fields of chemistry, physics, polymer science, and nanotechnology, its primary focus is on the design, formulation, and processing of intelligent viscoelastic surfactant solutions, covering the scientific principles governing responsiveness to one or more particular triggers, down to the end-use-driven functions. The first chapter explains why and how surfactants self-assemble into viscoelastic wormlike micellar solutions reminiscent of polymer solutions, while the following chapters show how the response to a given trigger translates into macroscopic rheological changes, including temperature, light, pH, CO2, redox, hydrocarbon, etc. The last chapter demonstrates the applications of these viscoelastic assemblies in oil and gas pro...

  3. Supramolecular hydrogels as drug delivery systems.

    Science.gov (United States)

    Saboktakin, Mohammad Reza; Tabatabaei, Roya Mahdavi

    2015-04-01

    Drug delivery from a hydrogel carrier implanted under the kidney capsule is an innovative way to induce kidney tissue regeneration and/or prevent kidney inflammation or fibrosis. We report here on the development of supramolecular hydrogels for this application. Chain-extended hydrogelators containing hydrogen bonding units in the main chain, and bifunctional hydrogelators end-functionalized with hydrogen bonding moieties, were made. The influence of these hydrogels on the renal cortex when implanted under the kidney capsule was studied. The overall tissue response to these hydrogels was found to be mild, and minimal damage to the cortex was observed, using the infiltration of macrophages, formation of myofibroblasts, and the deposition of collagen III as relevant read-out parameters. Differences in tissue response to these hydrogels could be related to the different physico-chemical properties of the three hydrogels.

  4. Patterns in swelling hydrogels

    Science.gov (United States)

    MacMinn, Chris; Bertrand, Thibault; Peixinho, Jorge; Mukhopadhyay, Shomeek

    2016-11-01

    Swelling is a process in which a porous material spontaneously grows by absorbing additional pore fluid. Polymeric hydrogels are highly deformable materials that can experience very large volume changes during swelling. This allows a small amount of dry gel to absorb a large amount of fluid, making gels extremely useful in applications from moisture control to drug delivery. However, a well-known consequence of these extreme volume changes is the emergence of a striking morphological instability. We study the transient mechanics of this instability here by combining a theoretical model with a series of simple experiments, focusing on the extent to which this instability can be controlled by manipulating the rate of swelling.

  5. Chain exchange in triblock copolymer micelles

    Science.gov (United States)

    Lu, Jie; Lodge, Timothy; Bates, Frank

    2015-03-01

    Block polymer micelles offer a host of technological applications including drug delivery, viscosity modification, toughening of plastics, and colloidal stabilization. Molecular exchange between micelles directly influences the stability, structure and access to an equilibrium state in such systems and this property recently has been shown to be extraordinarily sensitive to the core block molecular weight in diblock copolymers. The dependence of micelle chain exchange dynamics on molecular architecture has not been reported. The present work conclusively addresses this issue using time-resolved small-angle neutron scattering (TR-SANS) applied to complimentary S-EP-S and EP-S-EP triblock copolymers dissolved in squalane, a selective solvent for the EP blocks, where S and EP refer to poly(styrene) and poly(ethylenepropylene), respectively. Following the overall SANS intensity as a function of time from judiciously deuterium labelled polymer and solvent mixtures directly probes the rate of molecular exchange. Remarkably, the two triblocks display exchange rates that differ by approximately ten orders of magnitude, even though the solvophobic S blocks are of comparable size. This discovery is considered in the context of a model that successfully explains S-EP diblock exchange dynamics.

  6. Alginate-Collagen Fibril Composite Hydrogel.

    Science.gov (United States)

    Baniasadi, Mahmoud; Minary-Jolandan, Majid

    2015-02-16

    We report on the synthesis and the mechanical characterization of an alginate-collagen fibril composite hydrogel. Native type I collagen fibrils were used to synthesize the fibrous composite hydrogel. We characterized the mechanical properties of the fabricated fibrous hydrogel using tensile testing; rheometry and atomic force microscope (AFM)-based nanoindentation experiments. The results show that addition of type I collagen fibrils improves the rheological and indentation properties of the hydrogel.

  7. Alginate-Collagen Fibril Composite Hydrogel

    Directory of Open Access Journals (Sweden)

    Mahmoud Baniasadi

    2015-02-01

    Full Text Available We report on the synthesis and the mechanical characterization of an alginate-collagen fibril composite hydrogel. Native type I collagen fibrils were used to synthesize the fibrous composite hydrogel. We characterized the mechanical properties of the fabricated fibrous hydrogel using tensile testing; rheometry and atomic force microscope (AFM-based nanoindentation experiments. The results show that addition of type I collagen fibrils improves the rheological and indentation properties of the hydrogel.

  8. Structural properties of self-assembled polymeric micelles

    DEFF Research Database (Denmark)

    Mortensen, K.

    1998-01-01

    At present, the thermodynamic understanding of complex copolymer systems is undergoing important developments. Block copolymers aggregate in selective solvents into micelles of various form and size depending on molecular architecture and interaction parameters. The micelles constitute the basis...... for a variety of novel mesophases, including biocontinuous phases and networks of ordered cross-linking micelles. Research has focused on structural studies of block copolymer systems, using small-angle scattering of X-rays and neutrons....

  9. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  10. Magnetically Remanent Hydrogels with Colloidal Crosslinkers

    NARCIS (Netherlands)

    van Berkum, S.

    2014-01-01

    Hydrogels are widely used in biomedical applications such as drug delivery and tissue engineering. In this research, the feasibility of a hydrogel with embedded magnetic nanoparticles, also called a ferrogel, for biosensor applications was tested. A pH sensitive poly(acrylic acid) hydrogel was used

  11. Hydrogels with covalent and noncovalent crosslinks

    Science.gov (United States)

    Kilck, Kristi L. (Inventor); Yamaguchi, Nori (Inventor)

    2013-01-01

    A method for targeted delivery of therapeutic compounds from hydrogels is presented. The method involves administering to a cell a hydrogel in which a therapeutic compound is noncovalently bound to heparin. The hydrogel may contain covalent and non-covalent crosslinks.

  12. Magnetically Remanent Hydrogels with Colloidal Crosslinkers

    NARCIS (Netherlands)

    van Berkum, S.

    2014-01-01

    Hydrogels are widely used in biomedical applications such as drug delivery and tissue engineering. In this research, the feasibility of a hydrogel with embedded magnetic nanoparticles, also called a ferrogel, for biosensor applications was tested. A pH sensitive poly(acrylic acid) hydrogel was used

  13. The critical micelle concentration of tetraethylammonium perfluorooctylsulfonate in water.

    Science.gov (United States)

    López-Fontán, José L; González-Pérez, Alfredo; Costa, Julian; Ruso, Juan M; Prieto, Gerardo; Schulz, Pablo C; Sarmiento, Félix

    2006-02-15

    The aggregation characteristics of tetraethylammonium perfluorooctylsulfonate in water were studied by several techniques: conductivity, pH, ion-selective electrodes, and surface tension. It was concluded that the aggregation process is gradual and starts with the formation of oligomers such as ion pairs that grow to give spherical micelles, which become wormlike with increasing concentration. Because of the size and hydrophobicity of the counterion, micelles quickly increase in ionization degree up to about 0.5. Differences among different critical micelle concentration values in the literature are explained on the basis of the gradual formation of micelles.

  14. Dyeing Properties of Basofil Fiber

    Institute of Scientific and Technical Information of China (English)

    JIANG Hong; DAI Jin-jin

    2002-01-01

    The structures and properties of Basofil fiber were studied using X- rays small angle diffraction analysis,differential- scanuing calorimeter and scanning electron microscopy. Disperse dyes, acid dyes and reactive dyes had been tried for dyeing Basefil fiber. It was shown disperse dyes were superior to other ones. The two series of high temperature dyes and low temperature dyes were compared for their suitability for Basofil fiber, and their dyeing behaviors were determined.

  15. Benzidine Dyes Action Plan

    Science.gov (United States)

    This Action Plan addresses the use of benzidine-based dyes and benzidine congener-based dyes, both metalized and non-metalized, in products that would result in consumer exposure, such as for use to color textiles.

  16. Stimulus-responsiveness and methyl violet release behaviors of poly(NIPAAm-co-AA) hydrogels chemically crosslinked with β-cyclodextrin polymer bearing methacrylates.

    Science.gov (United States)

    Zhao, Hui; Gao, Jun; Liu, Ruina; Zhao, Sanping

    2016-06-16

    To fabricate thermo- and pH-sensitive hydrogels functionalized with β-cyclodextrin (β-CD) moieties, β-CD polymer bearing methacrylate (CDP-g-GMA) used as a reactive and functional crosslinker was synthesized, and then copolymerized with N-isopropylacrylamide (NIPAAm) and acrylic acid (AA) in aqueous solution via UV-initiated free radical polymerization. The stimulus-responsiveness of the resultant hydrogels has been carried out by measuring the swelling ratio at different temperatures and pH values. The results showed that the thermo- and pH-sensitivities of the produced hydrogels were significantly dependent on the compositions of the hydrogels, and the dual sensitivities exhibited good reversible process. The interior morphology observed by SEM exhibited that the pore size of the hydrogels could be tailored by pH of the local medium. Using a water-soluble cationic dye methyl violet (MV) as a model drug, MV loading and release profiles of the hydrogels as potential drug controlled release carriers were evaluated. The MV release rate from CD-functionalized hydrogels was much slower than that from the hydrogel without β-CDs at both pH 2.0 and pH 7.4. The release of MV from CD-functionalized hydrogels at pH 2.0 was faster than that at pH 7.4, the release kinetics of MV from the CD-functionalized hydrogels displayed a sustained release profile, and the release mechanism followed Fickian diffusion.

  17. Preparation and characterization of poly(2-acrylamido-2-methylpropane-sulfonic acid)/Chitosan hydrogel using gamma irradiation and its application in wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Gad, Y.H. [National Centre for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt)], E-mail: yasser2uk@yahoo.com

    2008-09-15

    Radiation grafting of chitosan with 2-acrylamido-2-methyl propane sulfonic acid (AMPS) has been successfully performed. The effect of absorbed dose (kGy) and the chitosan:AMPS ratio on graft hydrogelization was studied. The structure of the prepared hydrogel was confirmed using infrared spectroscopy (IR). Thermal properties were simultaneously studied by thermogravimetric analysis (TGA). The effect of the polymerization variables on the swelling % of the prepared hydrogel was investigated. The highest equilibrium degree of swelling (38.6 g/g) and gel % (94.7%) of the prepared chitosan-AMPS hydrogel was at 40% AMPS and absorbed dose of 10 kGy. The removal of methylene blue, acid red dye, Cd (II) and Cr (III) from composed wastewater was also investigated. The effect of pH, the chitosan:AMPS ratio and the concentration of the pollutant on the adsorption process were studied.

  18. Preparation and characterization of poly(2-acrylamido-2-methylpropane-sulfonic acid)/Chitosan hydrogel using gamma irradiation and its application in wastewater treatment

    Science.gov (United States)

    Gad, Y. H.

    2008-09-01

    Radiation grafting of chitosan with 2-acrylamido-2-methyl propane sulfonic acid (AMPS) has been successfully performed. The effect of absorbed dose (kGy) and the chitosan:AMPS ratio on graft hydrogelization was studied. The structure of the prepared hydrogel was confirmed using infrared spectroscopy (IR). Thermal properties were simultaneously studied by thermogravimetric analysis (TGA). The effect of the polymerization variables on the swelling % of the prepared hydrogel was investigated. The highest equilibrium degree of swelling (38.6 g/g) and gel % (94.7%) of the prepared chitosan-AMPS hydrogel was at 40% AMPS and absorbed dose of 10 kGy. The removal of methylene blue, acid red dye, Cd (II) and Cr (III) from composed wastewater was also investigated. The effect of pH, the chitosan:AMPS ratio and the concentration of the pollutant on the adsorption process were studied.

  19. Dyeing of Polypropylene Fibers with Vat Dyes

    Institute of Scientific and Technical Information of China (English)

    LIU Hang; ETTERS J. Nolan; LEONAS Karen K

    2006-01-01

    Polypropylene fibers have been extensively used in a variety of products, including carpets and upholstery, due to their non-absorbency, good weather resistance, good resistance to microorganisms and so on. Because of their hydrophobic and highly crystalline nature, those well-established conventional dyeing processes are difficult to apply to unmodified polypropylene. Colors of polypropylene fibers are primarily obtained by mass coloration which has the disadvantages of limited number of colors available and difficulties in inventory control due to the rapidly changing color needs of the market. In this paper, the use of vat dyes to dye polypropylene fabrics is investigated. Seventeen vat dyes were screened and factors influencing uptake of dyes by polypropylene fabrics were studied.

  20. Electrochemical characterization of hydrogels for biomimetic applications

    DEFF Research Database (Denmark)

    Peláez, L.; Romero, V.; Escalera, S.

    2011-01-01

    ) or a photoinitiator (P) to encapsulate and stabilize biomimetic membranes for novel separation technologies or biosensor applications. In this paper, we have investigated the electrochemical properties of the hydrogels used for membrane encapsulation. Specifically, we studied the crosslinked hydrogels by using...... electrochemical impedance spectroscopy (EIS), and we demonstrated that chemically crosslinked hydrogels had lower values for the effective electrical resistance and higher values for the electrical capacitance compared with hydrogels with photoinitiated crosslinking. Transport numbers were obtained using......〉 and 〈Pw〉 values than PEG‐1000‐DMA‐P and PEG‐400‐DA‐P hydrogels. In conclusion, our results show that hydrogel electrochemical properties can be controlled by the choice of polymer and type of crosslinking used and that their water and salt permeability properties are congruent with the use of hydrogels...

  1. Tough photoluminescent hydrogels doped with lanthanide.

    Science.gov (United States)

    Wang, Mei Xiang; Yang, Can Hui; Liu, Zhen Qi; Zhou, Jinxiong; Xu, Feng; Suo, Zhigang; Yang, Jian Hai; Chen, Yong Mei

    2015-03-01

    Photoluminescent hydrogels have emerged as novel soft materials with potential applications in many fields. Although many photoluminescent hydrogels have been fabricated, their scope of usage has been severely limited by their poor mechanical performance. Here, a facile strategy is reported for preparing lanthanide (Ln)-alginate/polyacrylamide (PAAm) hydrogels with both high toughness and photoluminescence, which has been achieved by doping Ln(3+) ions (Ln = Eu, Tb, Eu/Tb) into alginate/PAAm hydrogel networks, where Ln(3+) ions serve as both photoluminescent emitters and physical cross-linkers. The resulting hydrogels exhibit versatile advantages including excellent mechanical properties (∼ MPa strength, ≈ 20 tensile strains, ≈ 10(4) kJ m(-3) energy dissipation), good photoluminescent performance, tunable emission color, excellent processability, and cytocompatibility. The developed tough photoluminescent hydrogels hold great promises for expanding the usage scope of hydrogels.

  2. Biodegradable and thermoreversible PCLA-PEG-PCLA hydrogel as a barrier for prevention of post-operative adhesion.

    Science.gov (United States)

    Zhang, Zheng; Ni, Jian; Chen, Liang; Yu, Lin; Xu, Jianwei; Ding, Jiandong

    2011-07-01

    Biodegradable polymers can serve as barriers to prevent the post-operative intestinal adhesion. Herein, we synthesized a biodegradable triblock copolymer poly(ɛ-caprolactone-co-lactide)-b-poly(ethylene glycol)-b-poly(ɛ-caprolactone-co-lactide) (PCLA-PEG-PCLA). The concentrated polymeric aqueous solution was injectable, and a hydrogel could be rapidly formed due to percolation of a self-assembled micelle network at the body temperature without requirement of any chemical reactions. This physical hydrogel retained its integrity in vivo for a bit more than 6 weeks and was eventually degraded due to hydrolysis. The synthesized polymer exhibited little cytotoxicity and hemolysis; the acute inflammatory response after implanting the hydrogel was acceptable, and the degradation products were less acidic than those of other polyester-containing materials. A rabbit model of sidewall defect-bowel abrasion was employed, and a significant reduction of post-operative peritoneal adhesion has been found in the group of in situ formed PCLA-PEG-PCLA hydrogels.

  3. Multiparametric probing of microenvironment with solvatochromic fluorescent dyes.

    Science.gov (United States)

    Klymchenko, Andrey S; Demchenko, Alexander P

    2008-01-01

    We describe new methodology for multiparametric probing of weak non-covalent interactions in the medium based on response of environment-sensitive fluorescent dyes. The commonly used approach is based on correlation of one spectroscopic parameter (e.g. wavelength shift) with environment polarity, which describes a superposition of universal and specific (such as hydrogen bonding) interactions. In our approach, by using several independent spectroscopic parameters of a dye, we monitor simultaneously each individual type of the interactions. For deriving these extra parameters the selected dye should exist in several excited and/or ground states. In the present work, we applied 4'-(diethylamino)-3-hydroxyflavone, which undergoes the excited-state intramolecular proton transfer (ESIPT) and thus exhibits an additional emission band belonging to an ESIPT product (tautomer) form of the dye. The spectroscopic characteristics of the excited normal and the tautomer states as well as of the ESIPT reaction of the dye are differently sensitive to the different types of interactions with microenvironment and therefore can be used for its multiparametric description. The new methodology allowed us to monitor simultaneously three fundamental physicochemical parameters of probe microenvironment: polarity, electronic polarizability and H-bond donor ability. The applications of this approach to binary solvent mixtures, reverse micelles, lipid bilayers and binding sites of proteins are presented and the limitations of this approach are discussed. We believe that the methodology of multiparametric probing will extend the capabilities of fluorescent probes as the tools in biomolecular and cellular research.

  4. Stimuli-responsive biodegradable polymeric micelles for targeted cancer therapy

    NARCIS (Netherlands)

    Talelli, M.A.

    2011-01-01

    Thermosensitive and biodegradable polymeric micelles based on mPEG-b-pHPMAmLacn have shown very promising results during the past years. The results presented in this thesis illustrate the high potential of these micelles for anticancer therapy and imaging and fully justify further pharmaceutical

  5. DEFORMATION OF COPOLYMER MICELLES INDUCED BY AMPHIPHILIC DIMER PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Xiao-chun Qin; Chun-lai Ren

    2012-01-01

    Combining self-consistent-field theory and density-functional theory,we systematically study the deformation of copolymer micelles induced by the presence of amphiphilic dimer particles.Due to the amphiphilic nature,dimer particles tend to accumulate onto the interface of the copolymer micelle.With increasing concentration of the symmetric dimer particles,which are made of two identical spherical particles,the micelle deforms from the initial sphere to ellipse,dumbbell,and finally separates into two micelles.Furthermore,asymmetric dimer particles,composed by two particles with different sizes,are considered to investigate the influence of geometry of dimer particles on the deformation of the micelle.It is found that the micelle inclines to deform into dumbbell due to the additional curvature originating in the gathering of asymmetric dimer particles onto the interface of the micelle.The present study on the deformation of micelles is useful to understand the possible shape variation in the course of cell division/fusion.

  6. Absorption Complex between Porphyrin and Phenothiazine in Reverse Micelles

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The interaction between amphiphilic porphyrin and phenothiazine in AOT/isooctane/ water reverse micelle was investigated by UV-Vis spectra. A new absorption complex between the two species is formed in such circumstances, which is ascribed to the enrichment of the components by the reverse micelle. The fluorescence quenching of CHTTP by PTH becomes more efficient after the formation of the absorption complex.

  7. Anthracene functionalized thermosensitive and UV-crosslinkable polymeric micelles

    NARCIS (Netherlands)

    Shi, Yang; Cardoso, Renata M.; Van Nostrum, Cornelus F.; Hennink, Wim E.

    2015-01-01

    An anthracene-functionalized thermosensitive block copolymer was synthesized, which formed micelles by heating its aqueous solution above the lower critical solution temperature (LCST). The micelles were subsequently crosslinked by UV illumination at 365 nm with a normal handheld UV lamp. The micell

  8. Structure and stability of complex coacervate core micelles with lysozyme

    NARCIS (Netherlands)

    Lindhoud, Saskia; de Vries, Renko; Norde, Willem; Cohen Stuart, Martien A.

    Encapsulation of enzymes by polymers is a promising method to influence their activity and stability. Here, we explore the use of complex coacervate core micelles for encapsulation of enzymes. The core of the micelles consists of negatively charged blocks of the diblock copolymer PAA(42)PAAm(417)

  9. Structure and Stability of Complex Coacervate Core Micelles with Lysozyme

    NARCIS (Netherlands)

    Lindhoud, Saskia; de Vries, Renko; Norde, Willem; Cohen Stuart, Martinus Abraham

    2007-01-01

    Encapsulation of enzymes by polymers is a promising method to influence their activity and stability. Here, we explore the use of complex coacervate core micelles for encapsulation of enzymes. The core of the micelles consists of negatively charged blocks of the diblock copolymer PAA42PAAm417 and

  10. Structure and stability of complex coacervate core micelles with lysozyme

    NARCIS (Netherlands)

    Lindhoud, S.; Vries, de R.J.; Norde, W.; Cohen Stuart, M.A.

    2007-01-01

    Encapsulation of enzymes by polymers is a promising method to influence their activity and stability. Here, we explore the use of complex coacervate core micelles for encapsulation of enzymes. The core of the micelles consists of negatively charged blocks of the diblock copolymer PAA42PAAm417 and th

  11. Characterization of phospholipid mixed micelles by translational diffusion.

    Science.gov (United States)

    Chou, James J; Baber, James L; Bax, Ad

    2004-07-01

    The concentration dependence of the translational self diffusion rate, D (s), has been measured for a range of micelle and mixed micelle systems. Use of bipolar gradient pulse pairs in the longitudinal eddy current delay experiment minimizes NOE attenuation and is found critical for optimizing sensitivity of the translational diffusion measurement of macromolecules and aggregates. For low volume fractions Phi (Phi\\\\ le 15% v/v) of the micelles, experimental measurement of the concentration dependence, combined with use of the D (s)= D (o)(1-3.2lambdaPhi) relationship, yields the hydrodynamic volume. For proteins, the hydrodynamic volume, derived from D (s) at infinitely dilute concentration, is found to be about 2.6 times the unhydrated molecular volume. Using the data collected for hen egg white lysozyme as a reference, diffusion data for dihexanoyl phosphatidylcholine (DHPC) micelles indicate approximately 27 molecules per micelle, and a critical micelle concentration of 14 mM. Differences in translational diffusion rates for detergent and long chain phospholipids in mixed micelles are attributed to rapid exchange between free and micelle-bound detergent. This difference permits determination of the free detergent concentration, which, for a high detergent to long chain phospholipid molar ratio, is found to depend strongly on this ratio. The hydrodynamic volume of DHPC/POPC bicelles, loaded with an M2 channel peptide homolog, derived from translational diffusion, predicts a rotational correlation time that slightly exceeds the value obtained from peptide (15)N relaxation data.

  12. Characterization of Phospholipid Mixed Micelles by Translational Diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Chou, James J. [Harvard Medical School, Department of Biological Chemistry and Molecular Pharmacology (United States); Baber, James L.; Bax, Ad [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)], E-mail: bax@nih.gov

    2004-07-15

    The concentration dependence of the translational self diffusion rate, D{sub s}, has been measured for a range of micelle and mixed micelle systems. Use of bipolar gradient pulse pairs in the longitudinal eddy current delay experiment minimizes NOE attenuation and is found critical for optimizing sensitivity of the translational diffusion measurement of macromolecules and aggregates. For low volume fractions {phi} ({phi} {<=} 15% v/v) of the micelles, experimental measurement of the concentration dependence, combined with use of the D{sub s}=D{sub o}(1-3.2{lambda}{phi}) relationship, yields the hydrodynamic volume. For proteins, the hydrodynamic volume, derived from D{sub s} at infinitely dilute concentration, is found to be about 2.6 times the unhydrated molecular volume. Using the data collected for hen egg white lysozyme as a reference, diffusion data for dihexanoyl phosphatidylcholine (DHPC) micelles indicate approximately 27 molecules per micelle, and a critical micelle concentration of 14 mM. Differences in translational diffusion rates for detergent and long chain phospholipids in mixed micelles are attributed to rapid exchange between free and micelle-bound detergent. This difference permits determination of the free detergent concentration, which, for a high detergent to long chain phospholipid molar ratio, is found to depend strongly on this ratio. The hydrodynamic volume of DHPC/POPC bicelles, loaded with an M2 channel peptide homolog, derived from translational diffusion, predicts a rotational correlation time that slightly exceeds the value obtained from peptide {sup 15}N relaxation data.

  13. Chirality-mediated polypeptide micelles for regulated drug delivery.

    Science.gov (United States)

    Ding, Jianxun; Li, Chen; Zhang, Ying; Xu, Weiguo; Wang, Jincheng; Chen, Xuesi

    2015-01-01

    Two kinds of triblock poly(ethylene glycol)-polyleucine (PEG-PLeu) copolymers were synthesized through the ring-opening polymerization of L-Leu N-carboxyanhydride (NCA), or equivalent D-Leu NCA and L-Leu NCA with amino-terminated PEG as a macroinitiator. The amphiphilic copolymers spontaneously self-assembled into spherical micellar aggregations in an aqueous environment. The micelle with a racemic polypeptide core exhibited smaller critical micelle concentration and diameter compared to those with a levorotatory polypeptide core. A model anthracycline antineoplastic agent, i.e., doxorubicin (DOX), was loaded into micelles through nanoprecipitation, and the PEG-P(D,L-Leu) micelle exhibited higher drug-loading efficacy than that with a P(L-Leu) core-this difference was attributed to the flexible and compact P(L-Leu) core. Sustained in vitro DOX release from micelles with both levorotatory and racemic polypeptide cores was observed, and the DOX-loaded PEG-P(D,L-Leu) micelle exhibited a slower release rate. More interestingly, DOX-loaded micelles exhibited chirality-mediated antitumor efficacy in vitro and in vivo, which are all better than that of free DOX. Furthermore, both enhanced tumor inhibition and excellent security in vivo were confirmed by histopathological or in situ cell apoptosis analyses. Therefore, DOX-loaded PEG-PLeu micelles appear to be an interesting nanoscale polymeric formulation for promising malignancy chemotherapy.

  14. Designing Dendrimers to Offer Micelle-Type Nanocontainers

    Science.gov (United States)

    King, Angela G.

    2005-01-01

    The properties of a dendrimer with hydrophobic and hydrophilic substituents on an orthogonal plane is synthesized and studied. The resulting polymer contains one of the substituents in its concave interior and the other at the convex surface and the design promotes micelle-like behavior in polar solvent and inverted micelle arrangement in…

  15. Lactoferrin binding to transglutaminase cross-linked casein micelles

    NARCIS (Netherlands)

    Anema, S.G.; de Kruif, C.G.

    2012-01-01

    Casein micelles in skim milk were either untreated (untreated milk) or were cross-linked using transglutaminase (TGA-milk). Added lactoferrin (LF) bound to the casein micelles and followed Langmuir adsorption isotherms. The adsorption level was the same in both milks and decreased the micellar zeta

  16. Structure and Stability of Complex Coacervate Core Micelles with Lysozyme

    NARCIS (Netherlands)

    Lindhoud, Saskia; Vries, de Renko; Norde, Willem; Cohen Stuart, Martien A.

    2007-01-01

    Encapsulation of enzymes by polymers is a promising method to influence their activity and stability. Here, we explore the use of complex coacervate core micelles for encapsulation of enzymes. The core of the micelles consists of negatively charged blocks of the diblock copolymer PAA42PAAm417 and th

  17. Structure and stability of complex coacervate core micelles with lysozyme

    NARCIS (Netherlands)

    Lindhoud, Saskia; de Vries, Renko; Norde, Willem; Cohen Stuart, Martien A.

    2007-01-01

    Encapsulation of enzymes by polymers is a promising method to influence their activity and stability. Here, we explore the use of complex coacervate core micelles for encapsulation of enzymes. The core of the micelles consists of negatively charged blocks of the diblock copolymer PAA(42)PAAm(417) an

  18. Photoinduced charge separation and enzyme reactions in reversed micelles.

    NARCIS (Netherlands)

    Verhaert, R.M.D.

    1989-01-01

    In this thesis the performance and coupling of two types of reaction, photoinduced charge separation and enzymatic conversion were studied in reversed micelles. Reversed micelles are 1 to 10 nm sized water droplets dispersed in an organic solution. The dispersant is a detergent (cationogenic, nonion

  19. Determination of the Critical Micelle Concentration of Cationic Surfactants: An Undergraduate Experiment

    Science.gov (United States)

    Huang, Xirong; Yang, Jinghe; Zhang, Wenjuan; Zhang, Zhenyu; An, Zesheng

    1999-01-01

    A novel method based on the catalytic effect of micelles exerted by cetyltrimethylammonium bromide (CTAB) and cetylpyridinium bromide (CPB), respectively, on the indicator reaction between H2O2 and bromopyrogallol red (BPR), a triphenylmethane dye, was developed for undergraduates to determine the critical micelle concentration (cmc) of CTAB and CPB. The indicator reaction was monitored by a fixed-time kinetic-spectrophotometric technique. Under the experimental conditions the cmc values of CTAB and CPB were (4.8 ± 0.3) x 10-4 mol/L and (4.5 ± 0.3) x 10-4mol/L, which were close to the literature values of 9.2 x 10-4 mol/L and 9.0 x 10-4 mol/L, respectively. Detailed discussion on the selection of experimental conditions was made to minimize the effect of electrolytes on the cmc's of surfactants and to maintain the high accuracy of the experimental data. As an undergraduate physicochemical laboratory experiment the present method had several attractive features. The procedure is simple and easy to perform, does not require special equipment, and does not need expensive or toxic reagents. In addition, it is a versatile method that can be applied to a wide variety of both anionic and cationic surfactants.

  20. Designed biodegradable hydrogel structures prepared by stereolithography using poly(ethylene glycol)/poly(D,L-lactide)-based resins.

    Science.gov (United States)

    Seck, Tetsu M; Melchels, Ferry P W; Feijen, Jan; Grijpma, Dirk W

    2010-11-20

    Designed three-dimensional biodegradable poly(ethylene glycol)/poly(D,L-lactide) hydrogel structures were prepared for the first time by stereolithography at high resolutions. A photo-polymerisable aqueous resin comprising PDLLA-PEG-PDLLA-based macromer, visible light photo-initiator, dye and inhibitor in DMSO/water was used to build the structures. Porous and non-porous hydrogels with well-defined architectures and good mechanical properties were prepared. Porous hydrogel structures with a gyroid pore network architecture showed narrow pore size distributions, excellent pore interconnectivity and good mechanical properties. The structures showed good cell seeding characteristics, and human mesenchymal stem cells adhered and proliferated well on these materials.

  1. Fluorescent dye N,N'-dioctadecylrhodamine as a new interfacial acid-base indicator.

    Science.gov (United States)

    McHedlov-Petrossyan, N O; Vodolazkaya, N A; Bezkrovnaya, O N; Yakubovskaya, A G; Tolmachev, A V; Grigorovich, A V

    2008-04-01

    This paper reports the spectral properties and protolytic behavior of the fluorescent dye N,N'-dioctadecylrhodamine on the micelle/water and microdroplet/water interfaces as well as in Langmuir-Blodgett films soaked into aqueous media. Long hydrocarbon chains provide similar orientation of its cation and zwitterion, with the dissociating group (COOH-->COO(-)) directed toward the bulk (aqueous) phase. Both absorption and fluorescence of the dye can be used for monitoring electrical surface potentials and for determination of bulk pH.

  2. Hair dye contact allergy

    DEFF Research Database (Denmark)

    Søsted, Heidi; Rastogi, Suresh Chandra; Andersen, Klaus Ejner

    2004-01-01

    Colouring of hair can cause severe allergic contact dermatitis. The most frequently reported hair dye allergens are p-phenylenediamine (PPD) and toluene-2,5-diamine, which are included in, respectively, the patch test standard series and the hairdressers series. The aim of the present study...... was to identify dye precursors and couplers in hair dyeing products causing clinical hair dye dermatitis and to compare the data with the contents of these compounds in a randomly selected set of similar products. The patient material comprised 9 cases of characteristic clinical allergic hair dye reaction, where...... exposure history and patch testing had identified a specific hair dye product as the cause of the reaction. The 9 products used by the patients were subjected to chemical analysis. 8 hair dye products contained toluene-2,5-diamine (0.18 to 0.98%). PPD (0.27%) was found in 1 product, and m-aminophenol (0...

  3. Ultrasonic dyeing of cellulose nanofibers.

    Science.gov (United States)

    Khatri, Muzamil; Ahmed, Farooq; Jatoi, Abdul Wahab; Mahar, Rasool Bux; Khatri, Zeeshan; Kim, Ick Soo

    2016-07-01

    Textile dyeing assisted by ultrasonic energy has attained a greater interest in recent years. We report ultrasonic dyeing of nanofibers for the very first time. We chose cellulose nanofibers and dyed with two reactive dyes, CI reactive black 5 and CI reactive red 195. The cellulose nanofibers were prepared by electrospinning of cellulose acetate (CA) followed by deacetylation. The FTIR results confirmed complete conversion of CA into cellulose nanofibers. Dyeing parameters optimized were dyeing temperature, dyeing time and dye concentrations for each class of the dye used. Results revealed that the ultrasonic dyeing produced higher color yield (K/S values) than the conventional dyeing. The color fastness test results depicted good dye fixation. SEM analysis evidenced that ultrasonic energy during dyeing do not affect surface morphology of nanofibers. The results conclude successful dyeing of cellulose nanofibers using ultrasonic energy with better color yield and color fastness results than conventional dyeing.

  4. Precipitate-Coacervate Transformation in Polyelectrolyte-Mixed Micelle Systems.

    Science.gov (United States)

    Comert, Fatih; Nguyen, Duy; Rushanan, Marguerite; Milas, Peker; Xu, Amy Y; Dubin, Paul L

    2017-05-04

    The polycation/anionic-nonionic mixed micelle, poly(diallyldimethylammonium chloride)-sodium dodecyl sulfate/Triton X-100 (PDADMAC-SDS/TX100), is a model polyelectrolyte-colloid system in that the micellar mole fraction of SDS (Y) controls the micelle surface charge density, thus modulating the polyelectrolyte-colloid interaction. The exquisite temperature dependence of this system provides an important additional variable, controlling both liquid-liquid (L-L) and liquid-solid (L-S) phase separation, both of which are driven by the entropy of small ion release. In order to elucidate these transitions, we applied high-precision turbidimetry (±0.1 %), isothermal titration calorimetry, and epifluorescence microscopy which demonstrates preservation of micelle structure under all conditions. The L-S region at large Y including precipitation displays a remarkable linear, inverse Y-dependence of the L-S transition temperature Ts. In sharp contrast, the critical temperature for L-L coacervation Tφ, shows nearly symmetrical effects of positive and negative deviations in Y from the point of soluble complex neutrality, which is controlled in solution by the micelle charge and the number of micelles bound per polymer chain n (Zcomplex = Zpolymer + nZmicelle). In solid-like states, n no longer signifies the number of micelles bound per polymer chain, since the proximity of micelles inverts the host-guest relationship with each micelle binding multiple PE chains. This intimate binding goes hand-in-hand with the entropy of release of micelle-localized charge-compensating ions whose concentration depends on Y. These ions need not be released in L-L coacervation, but during L-S transition their displacement by PE accounts for the inverse dependence of Ts on micelle charge, Y.

  5. Fabrication of keratin-silica hydrogel for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kakkar, Prachi; Madhan, Balaraman, E-mail: bmadhan76@yahoo.co.in

    2016-09-01

    In the recent past, keratin has been fabricated into different forms of biomaterials like scaffold, gel, sponge, film etc. In lieu of the myriad advantages of the hydrogels for biomedical applications, a keratin-silica hydrogel was fabricated using tetraethyl orthosilicate (TEOS). Textural analysis shed light on the physical properties of the fabricated hydrogel, inturn enabling the optimization of the hydrogel. The optimized keratin-silica hydrogel was found to exhibit instant springiness, optimum hardness, with ease of spreadability. Moreover, the hydrogel showed excellent swelling with highly porous microarchitecture. MTT assay and DAPI staining revealed that keratin-silica hydrogel was biocompatible with fibroblast cells. Collectively, these properties make the fabricated keratin-silica hydrogel, a suitable dressing material for biomedical applications. - Highlights: • Keratin-silica hydrogel has been fabricated using sol–gel technique. • The hydrogel shows appropriate textural properties. • The hydrogel promotes fibroblast cells proliferation. • The hydrogel has potential soft tissue engineering applications like wound healing.

  6. Therapeutic surfactant-stripped frozen micelles

    Science.gov (United States)

    Zhang, Yumiao; Song, Wentao; Geng, Jumin; Chitgupi, Upendra; Unsal, Hande; Federizon, Jasmin; Rzayev, Javid; Sukumaran, Dinesh K.; Alexandridis, Paschalis; Lovell, Jonathan F.

    2016-05-01

    Injectable hydrophobic drugs are typically dissolved in surfactants and non-aqueous solvents which can induce negative side-effects. Alternatives like `top-down' fine milling of excipient-free injectable drug suspensions are not yet clinically viable and `bottom-up' self-assembled delivery systems usually substitute one solubilizing excipient for another, bringing new issues to consider. Here, we show that Pluronic (Poloxamer) block copolymers are amenable to low-temperature processing to strip away all free and loosely bound surfactant, leaving behind concentrated, kinetically frozen drug micelles containing minimal solubilizing excipient. This approach was validated for phylloquinone, cyclosporine, testosterone undecanoate, cabazitaxel and seven other bioactive molecules, achieving sizes between 45 and 160 nm and drug to solubilizer molar ratios 2-3 orders of magnitude higher than current formulations. Hypertonic saline or co-loaded cargo was found to prevent aggregation in some cases. Use of surfactant-stripped micelles avoided potential risks associated with other injectable formulations. Mechanistic insights are elucidated and therapeutic dose responses are demonstrated.

  7. Heparin release from thermosensitive hydrogels

    NARCIS (Netherlands)

    Gutowska, Anna; Bae, You Han; Feijen, Jan; Kim, Sung Wan

    1992-01-01

    Thermosensitive hydrogels (TSH) were synthesized and investigated as heparin releasing polymers for the prevention of surface induced thrombosis. TSH were synthesized with N-isopropyl acrylamide (NiPAAm) copolymerized with butyl methacrylate (BMA) (hydrophobic) or acrylic acid (AAc) (hydrophilic) co

  8. Polyvinyl alcohol hydrogels for iontohporesis

    Science.gov (United States)

    Bera, Prasanta; Alam, Asif Ali; Arora, Neha; Tibarewala, Dewaki Nandan; Basak, Piyali

    2013-06-01

    Transdermal therapeutic systems propound controlled release of active ingredients through the skin into the systemic circulation in a predictive manner. Drugs administered through these systems escape first-pass metabolism and maintain a steady state scenario similar to a continuous intravenous infusion for up to several days. The iontophoresis deal with the systemic delivery of the bioactive agents (drug) by applying an electric current. It is basically an injection without the needle. The iontophoretic system requires a gel-based matrix to accommodate the bioactive agent. Hydrogels have been used by many investigators in controlled-release drug delivery systems because of their good tissue compatibility and easy manipulation of swelling level and, thereby, solute permeability. In this work we have prepared polyvinyl alcohol (PVA) hydrogel. We have cross linked polyvinyl alcohol chemically with Glutaraldehyde with different wt%. FTIR study reveals the chemical changes during cross linking. Swelling in water, is done to have an idea about drug loading and drug release from the membrane. After drug loading to the hydrogels, we have studied the drug release property of the hydrogels using salicylic acid as a model drug.

  9. Hydrogels for therapeutic cardiovascular angiogenesis.

    Science.gov (United States)

    Rufaihah, Abdul Jalil; Seliktar, Dror

    2016-01-15

    Acute myocardial infarction (MI) caused by ischemia is the most common cause of cardiac dysfunction. While growth factor or cell therapy is promising, the retention of bioactive agents in the highly vascularized myocardium is limited and prevents sustained activation needed for adequate cellular responses. Various types of biomaterials with different physical and chemical properties have been developed to improve the localized delivery of growth factor and/or cells for therapeutic angiogenesis in ischemic tissues. Hydrogels are particularly advantageous as carrier systems because they are structurally similar to the tissue extracellular matrix (ECM), they can be processed under relatively mild conditions and can be delivered in a minimally invasive manner. Moreover, hydrogels can be designed to degrade in a timely fashion that coincides with the angiogenic process. For these reasons, hydrogels have shown great potential as pro-angiogenic matrices. This paper reviews a few of the hydrogel systems currently being applied together with growth factor delivery and/or cell therapy to promote therapeutic angiogenesis in ischemic tissues, with emphasis on myocardial applications.

  10. Cluster dynamics, growth and syneresis during silica hydrogel polymerisation

    Science.gov (United States)

    Birch, David J. S.; Geddes, Chris D.

    2000-04-01

    The aggregation and syneresis of silica particles during hydrogel polymerisation has been observed in situ for the first time with near-Å resolution using a new approach based on the combined fluorescence anisotropy decay of solvated and bound dye molecules. Primary particles of mean hydrodynamic diameter ˜1.5 nm are found to be present within 20 min of mixing sodium silicate solution and sulphuric acid. Clustering then occurs during siloxane polymerisation to produce after ˜30 h secondary particles with a mean diameter up to ˜4.5 nm at a growth rate which depends on silicate concentration and time to microgelation, tg. Subsequent condensation to ˜4 nm diameter occurs within 1 week as particle syneresis dominates. The effects on particle growth of adding D 2O and inorganic salts are demonstrated.

  11. Peptide hydrogelation triggered by enzymatic induced pH switch

    Science.gov (United States)

    Cheng, Wei; Li, Ying

    2016-07-01

    It remains challenging to develop methods that can precisely control the self-assembling kinetics and thermodynamics of peptide hydrogelators to achieve hydrogels with optimal properties. Here we report the hydrogelation of peptide hydrogelators by an enzymatically induced pH switch, which involves the combination of glucose oxidase and catalase with D-glucose as the substrate, in which both the gelation kinetics and thermodynamics can be controlled by the concentrations of D-glucose. This novel hydrogelation method could result in hydrogels with higher mechanical stability and lower hydrogelation concentrations. We further illustrate the application of this hydrogelation method to differentiate different D-glucose levels.

  12. Investigation of laundering and dispersion approaches for silica and calcium phosphosilicate composite nanoparticles synthesized in reverse micelles

    Science.gov (United States)

    Tabakovic, Amra

    Nanotechnology, the science and engineering of materials at the nanoscale, is a booming research area with numerous applications in electronic, cosmetic, automotive and sporting goods industries, as well as in biomedicine. Composite nanoparticles (NPs) are of special interest since the use of two or more materials in NP design imparts multifunctionality on the final NP constructs. This is especially relevant for applications in areas of human healthcare, where the use of dye or drug doped composite NPs is expected to improve the diagnosis and treatment of cancer and other serious illnesses. Since the physicochemical properties of NP suspensions dictate the success of these systems in biomedical applications, especially drug delivery of chemotherapeutics, synthetic routes which offer precise control of NP properties, especially particle diameter and colloidal stability, are utilized to form a variety of composite NPs. Formation of NPs in reverse, or water-in-oil, micelles is one such synthetic approach. However, while the use of reverse micelles to form composite NPs offers precise control over NP size and shape, the post-synthesis laundering and dispersion of synthesized NP suspensions can still be a challenge. Reverse micelle synthetic approaches require the use of surfactants and low dielectric constant solvents, like hexane and cyclohexane, as the oil phase, which can compromise the biocompatibility and colloidal stability of the final composite NP suspensions. Therefore, appropriate dispersants and solvents must be used during laundering and dispersion to remove surfactant and ensure stability of synthesized NPs. In the work presented in this dissertation, two laundering and dispersion approaches, including packed column high performance liquid chromatography (HPLC) and centrifugation (sedimentation and redispersion), are investigated for silver core silica (Ag-SiO2) and calcium phosphosilicate (Caw(HxPO4)y(Si(OH)zOa) b · cH2O, CPS) composite NP suspensions

  13. Effect of temperature, water content and free fatty acid on reverse micelle formation of phospholipids in vegetable oil.

    Science.gov (United States)

    Lehtinen, Olli-Pekka; Nugroho, Robertus Wahyu N; Lehtimaa, Tuula; Vierros, Sampsa; Hiekkataipale, Panu; Ruokolainen, Janne; Sammalkorpi, Maria; Österberg, Monika

    2017-09-22

    The self-assembly of phospholipids in oil, specifically lecithin in rapeseed oil, was investigated by combining experimental and computational methods The influence of temperature, water, and free fatty acids on the onset of lecithin aggregation in the rapeseed oil was determined using the 7,7,8,8 -tetracyanoquinodimethane dye (TCNQ) solubilization method and the size and shape of the self-assembled lecithin structures were investigated by small-angle X-ray scattering and cryogenic transmission electron microscopy. In the absence of excess water in the system (0.03wt-% water in oil), stable cylindrical lecithin reverse micelles were observed above the critical micelle concentration (CMC). Comparing the aggregation response in room temperature and at 70°C revealed that CMC decreased with increasing temperature. Furthermore, already a modest amount of added water (0.3wt-% water in oil) was sufficient to induce the formation of lamellar lecithin structures, that phase separated from the oil. In low water content, oleic acid suppressed the formation of lecithin reverse micelles whereas in the presence of more water, the oleic acid stabilized the reverse micelles. Consequently, more water was needed to induce phase separation in the presence of oleic acid. Molecular dynamics simulations indicated that the stabilizing effect of oleic acid resulted from oleic acid enhancing phospholipid solubilization in the oil by forming a solvating shell around the phosphate head group. The findings showed that the response of the mixed surfactant system is a delicate interplay of the different components and variables. The significance of the observations is that multiple parameters need to be controlled for desired system response, for example towards vegetable oil purification or phospholipid based microemulsions. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Dynamic Gradient Directed Molecular Transport and Concentration in Hydrogel Films.

    Science.gov (United States)

    Tsai, Tsung-Han; Ali, Mohammad A; Jiang, Zhelong; Braun, Paul V

    2017-04-24

    Materials which selectively transport molecules along defined paths offer new opportunities for concentrating, processing and sensing chemical and biological agents. Here, we present the use of traveling ionic waves to drive molecular transport and concentration of hydrophilic molecules entrained within a hydrogel. The traveling ionic wave is triggered by the spatially localized introduction of ions, which through a dissipative ion exchange process, converts quaternary ammonium groups in the hydrogel from hydrophilic to hydrophobic. Through a reaction-diffusion process, the hydrophobic region expands with a sharp transition at the leading edge; it is this sharp gradient in hydrophilicity that drives the transport of hydrophilic molecules dispersed within the film. The traveling wave moved up to 450 μm within 30 min, while the gradient length remained 20 μm over this time. As an example of the potential of molecular concentration using this approach, a 70-fold concentration of a hydrophilic dye was demonstrated. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Ultrasonic transformation of micelle structures: effect of frequency and power.

    Science.gov (United States)

    Yusof, Nor Saadah Mohd; Ashokkumar, Muthupandian

    2015-05-01

    A comprehensive investigation on the effect of ultrasonic frequency and power on the structural transformation of CTABr/NaSal micelles has been carried out. Sonication of this micelle system at various ultrasonic frequencies and power resulted in the formation and separation of two types of micelles. High viscoelastic threadlike micelles of ∼ 2 nm in diameter and several μm in length and tubular micelles possessing a viscosity slightly above that of water with ∼ 30-50 nm diameter and few hundred nm length. The structural transformation of micelles was induced by the shear forces generated during acoustic cavitation. At a fixed acoustic power of 40 W, the structural transformation was found to decrease from 211 to 647 kHz frequency due to the decreasing shear forces generated, as evidenced by rheological measurements and cryo-TEM images. At 355 kHz, an increase in the structural transformation was observed with an increase in acoustic power. These findings provide a knowledge base that could be useful for the manipulation of viscosity of micelles that may have applications in oil industry.

  16. An amidated carboxymethylcellulose hydrogel for cartilage regeneration.

    Science.gov (United States)

    Leone, Gemma; Fini, Milena; Torricelli, Paola; Giardino, Roberto; Barbucci, Rolando

    2008-08-01

    An amidic derivative of carboxymethylcellulose was synthesized (CMCA). The new polysaccharide was obtained by converting a large percentage of carboxylic groups ( approximately 50%) of carboxymethylcellulose into amidic groups rendering the macromolecule quite similar to hyaluronan. Then, the polysaccharide (CMCA) was crosslinked. The behavior of CMCA hydrogel towards normal human articular chondrocytes (NHAC) was in vitro studied monitoring the cell proliferation and synthesis of extra cellular matrix (ECM) components and compared with a hyaluronan based hydrogel (Hyal). An extracellular matrix rich in cartilage-specific collagen and proteoglycans was secreted in the presence of hydrogels. The injectability of the new hydrogels was also analysed. An experimental in vivo model was realized to study the effect of CMCA and Hyal hydrogels in the treatment of surgically created partial thickness chondral defects in the rabbit knee. The preliminary results pointed out that CMCA hydrogel could be considered as a potential compound for cartilage regeneration.

  17. Hydrogels for Engineering of Perfusable Vascular Networks.

    Science.gov (United States)

    Liu, Juan; Zheng, Huaiyuan; Poh, Patrina S P; Machens, Hans-Günther; Schilling, Arndt F

    2015-07-14

    Hydrogels are commonly used biomaterials for tissue engineering. With their high-water content, good biocompatibility and biodegradability they resemble the natural extracellular environment and have been widely used as scaffolds for 3D cell culture and studies of cell biology. The possible size of such hydrogel constructs with embedded cells is limited by the cellular demand for oxygen and nutrients. For the fabrication of large and complex tissue constructs, vascular structures become necessary within the hydrogels to supply the encapsulated cells. In this review, we discuss the types of hydrogels that are currently used for the fabrication of constructs with embedded vascular networks, the key properties of hydrogels needed for this purpose and current techniques to engineer perfusable vascular structures into these hydrogels. We then discuss directions for future research aimed at engineering of vascularized tissue for implantation.

  18. Stereocomplex micelle from nonlinear enantiomeric copolymers efficiently transports antineoplastic drug

    Science.gov (United States)

    Wang, Jixue; Shen, Kexin; Xu, Weiguo; Ding, Jianxun; Wang, Xiaoqing; Liu, Tongjun; Wang, Chunxi; Chen, Xuesi

    2015-05-01

    Nanoscale polymeric micelles have attracted more and more attention as a promising nanocarrier for controlled delivery of antineoplastic drugs. Herein, the doxorubicin (DOX)-loaded poly(D-lactide)-based micelle (PDM/DOX), poly(L-lactide)-based micelle (PLM/DOX), and stereocomplex micelle (SCM/DOX) from the equimolar mixture of the enantiomeric four-armed poly(ethylene glycol)-polylactide (PEG-PLA) copolymers were successfully fabricated. In phosphate-buffered saline (PBS) at pH 7.4, SCM/DOX exhibited the smallest hydrodynamic diameter ( D h) of 90 ± 4.2 nm and the slowest DOX release compared with PDM/DOX and PLM/DOX. Moreover, PDM/DOX, PLM/DOX, and SCM/DOX exhibited almost stable D hs of around 115, 105, and 90 nm at above normal physiological condition, respectively, which endowed them with great potential in controlled drug delivery. The intracellular DOX fluorescence intensity after the incubation with the laden micelles was different degrees weaker than that incubated with free DOX · HCl within 12 h, probably due to the slow DOX release from micelles. As the incubation time reached to 24 h, all the cells incubated with the laden micelles, especially SCM/DOX, demonstrated a stronger intracellular DOX fluorescence intensity than free DOX · HCl-cultured ones. More importantly, all the DOX-loaded micelles, especially SCM/DOX, exhibited potent antineoplastic efficacy in vitro, excellent serum albumin-tolerance stability, and satisfactory hemocompatibility. These encouraging data indicated that the loading micelles from nonlinear enantiomeric copolymers, especially SCM/DOX, might be promising in clinical systemic chemotherapy through intravenous injection.

  19. A study on the adsorption of methylene blue onto gum ghatti/TiO2 nanoparticles-based hydrogel nanocomposite.

    Science.gov (United States)

    Mittal, Hemant; Ray, Suprakas Sinha

    2016-07-01

    The objective of this work was to study the isotherm and kinetic models for the adsorption of methylene blue (MB) onto a TiO2 nanoparticle (TiO2NP)-containing hydrogel nanocomposite (HNC) of polyacrylamide-grafted gum ghatti (PAAm-g-Gg). The grafting of PAAm onto Gg was conducted using N,N'-methylene-bis-acrylamide (MBA) as a crosslinker, and different weight percentages of TiO2NPs were incorporated into the hydrogel matrix during the grafting reaction. The graft co-polymerization and the formation of the HNC were confirmed using FTIR, XRD, BET, SEM, TEM and EDS analyses. The adsorption of MB was studied in batch mode and it was found to be highly dependent on solution pH, ionic strength temperature and adsorbent loading. The MB-adsorption process followed the pseudo-second-order rate model and Langmuir adsorption isotherm with a maximum adsorption capacity of 1305.5mgg(-1). Thermodynamic studies revealed that the adsorption of MB onto the HNC surface was spontaneous, endothermic and through a process of physisorption. The results also showed that the HNC was much more effective for the adsorption of cationic dyes than anionic dyes, and it retained its original adsorption capacity for five successive cycles of adsorption-desorption. In conclusion, the hydrogel nanocomposite showed huge potential for remediating industrial wastewater polluted by toxic cationic dyes.

  20. Energy transfer from a dye donor to enhance the luminescence of silicon quantum dots

    Science.gov (United States)

    Erogbogbo, Folarin; Chang, Ching-Wen; May, Jasmine; Prasad, Paras N.; Swihart, Mark T.

    2012-07-01

    Quantum dots are known for their superior optical properties; however, when transferred into aqueous media, their luminescent properties are frequently compromised. When encapsulated in micelles for bioimaging applications, luminescent silicon quantum dots can lose as much as 50% of their luminescence depending on the formulation used. Here, we create an energy transfer micelle platform that combines silicon quantum dots with an anthracene-based dye in the hydrophobic core of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] (DSPE-PEG) micelles. These phospholipid micelles are water dispersible, stable, and surrounded by a PEGylated layer with modifiable functional groups. The spectroscopic properties of energy transfer between the anthracene donors and silicon quantum dot acceptors were analyzed based on the observed dependence of the steady-state emission spectrum on concentration ratio, excitation wavelength, pH, and temperature. The luminescence of silicon quantum dots from the core of a 150 nm micelle is enhanced by more than 80% when the anthracene dye is added. This work provides a simple yet readily applicable solution to the long-standing problem of luminescence enhancement of silicon quantum dots and can serve as a template for improving the quantum dot emission yield for biological applications where luminescence signal enhancements are desirable and for solar applications where energy transfer plays a critical role in device performance.Quantum dots are known for their superior optical properties; however, when transferred into aqueous media, their luminescent properties are frequently compromised. When encapsulated in micelles for bioimaging applications, luminescent silicon quantum dots can lose as much as 50% of their luminescence depending on the formulation used. Here, we create an energy transfer micelle platform that combines silicon quantum dots with an anthracene-based dye in the hydrophobic core of 1

  1. Self-assembly of micelles into designed networks

    Directory of Open Access Journals (Sweden)

    Pyatenko Alexander

    2007-01-01

    Full Text Available AbstractThe EO20PO70EO20(molecular weight 5800 amphiphile as a template is to form dispersed micelle structures. Silver nanoparticles, as inorganic precursors synthesized by a laser ablation method in pure water, are able to produce the highly ordered vesicles detected by TEM micrography. The thickness of the outer layer of a micelle, formed by the silver nanoparticles interacting preferentially with the more hydrophilic EO20block, was around 3.5 nm. The vesicular structure ensembled from micelles is due to proceeding to the mixture of cubic and hexagonal phases.

  2. Pressure-induced structural transition of nonionic micelles

    Indian Academy of Sciences (India)

    V K Aswal; R Vavrin; J Kohlbrecher; A G Wagh

    2008-11-01

    We report dynamic light scattering and small angle neutron scattering studies of the pressure-induced structural transition of nonionic micelles of surfactant polyoxyethylene 10 lauryl ether (C12E10) in the pressure range 0 to 2000 bar. Measurements have been performed on 1 wt% C12E10 in aqueous solution with and without the addition of KF. Micelles undergo sphere to lamellar structural transitions as the pressure is increased. On addition of KF, rod-like micelles exist at ambient pressure, which results in rod-like to lamellar structural transition at a much lower pressure in the presence of KF. Micellar structural transitions have been observed to be reversible.

  3. Dyes as teratogens.

    Science.gov (United States)

    Sandor, S

    1992-01-01

    The main fats and problems of the role of dyes in prenatal pathology are reviewed. The first section deals with the practical aspects related to teratological screening of industrial dyes (including also the results obtained in this laboratory). In the second section, various aspects of azo-dye teratogenesis are largely discussed, including also the experimental contributions of this laboratory. Concluding remarks are made with respect to the importance and to the perspectives of this field of research.

  4. A new type of chitosan hydrogel sorbent generated by anionic surfactant gelation.

    Science.gov (United States)

    Chatterjee, Sudipta; Chatterjee, Tania; Woo, Seung H

    2010-06-01

    A new type of chitosan hydrogel beads (CSB) with a core-shell membrane structure was generated by sodium dodecyl sulfate (SDS) gelation process. CSB exhibited higher mechanical strength and acid stability than chitosan hydrogel beads (CB) formed by alkali gelation. The effect of SDS concentration variation during gelation on the adsorption capacity of CSB for congo red (CR) as a model anionic dye showed that CSB formed by 4gl(-1) SDS gelation had the highest adsorption capacity. The maximum adsorption capacity of CSB (208.3mgg(-1)) obtained from the Sips model was found slightly higher than that of CB (200.0mgg(-1)). Membrane materials of CSB obtained after squeezing core water from the beads showed approximately 25 times higher volumetric adsorption capacity than CB.

  5. Effect of compressed CO2 on the critical micelle concentration and aggregation number of AOT reverse micelles in isooctane.

    Science.gov (United States)

    Chen, Jing; Zhang, Jianling; Han, Buxing; Feng, Xiaoying; Hou, Minqiang; Li, Wenjing; Zhang, Zhaofu

    2006-10-25

    The effect of compressed CO2 on the critical micelle concentration (cmc) and aggregation number of sodium bis-2-ethylhexylsulfosuccinate (AOT) reverse micelles in isooctane solution was studied by UV/Vis and fluorescence spectroscopy methods in the temperature range of 303.2-318.2 K and at different pressures or mole fractions of CO2 (X(CO2)). The capacity of the reverse micelles to solubilize water was also determined by direct observation. The standard Gibbs free energy (DeltaGo(m)), standard enthalpy (DeltaHo(m)), and standard entropy (DeltaSo(m)) for the formation of the reverse micelles were calculated by using the cmc data determined. It was discovered that the cmc versus X(CO2) curve and the DeltaGo(m) versus X(CO2) curve for a fixed temperature have a minimum, and the aggregation number and water-solubilization capacity of the reverse micelles reach a maximum at the X(CO2) value corresponding to that minimum. These results indicate that CO2 at a suitable concentration favors the formation of and can stabilize AOT reverse micelles. A detailed thermodynamic study showed that the driving force for the formation of the reverse micelles is entropy.

  6. Anion Exchange on Cationic Surfactant Micelles, and a Speciation Model for Estimating Anion Removal on Micelles during Ultrafiltration of Water.

    Science.gov (United States)

    Chen, Ming; Jafvert, Chad T

    2017-07-05

    Surfactant micelles combined with ultrafiltration can partially, or sometimes nearly completely, separate various ionic and nonionic pollutants from water. To this end, the selectivity of aqueous micelles composed of either cetyltrimethylammonium (CTA(+)) bromide or cetylpyridinium (CP(+)) chloride toward many environmentally relevant anions (IO3(-), F(-), Cl(-), HCO3(-), NO2(-), Br(-), NO3(-), H2PO4(-), HPO4(2-), SO4(2-), and CrO4(2-)) was investigated. Selectivity coefficients of CTA(+) micelles (with respect to Br(-)) and CP(+) micelle (with respect to Cl(-)) for these anions were evaluated using a simple thermodynamic ion exchange model. The sequence of anion affinity for the CTA(+) micelles and for the CP(+) micelles were the same, with decreasing affinity occurring in the order of: CrO4(2-) > SO4(2-) > HPO4(2-) > NO3(-) > Br(-) > NO2(-) > Cl(-) > HCO3(-) > H2PO4(-) ≈ F(-). From the associated component mass balance and ion exchange (i.e., mass action) equations, an overall speciation model was developed to predict the distribution of all anions between the aqueous and micellar pseudophase for complex ionic mixtures. Experimental results of both artificial and real surface waters were in good agreement to model predictions. Further, the results indicated that micelles combined with ultrafiltration may be a potential technology for nutrient and other pollutant removal from natural or effluent waters.

  7. Injectable, Biodegradable Hydrogels for Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Huaping Tan

    2010-03-01

    Full Text Available Hydrogels have many different applications in the field of regenerative medicine. Biodegradable, injectable hydrogels could be utilized as delivery systems, cell carriers, and scaffolds for tissue engineering. Injectable hydrogels are an appealing scaffold because they are structurally similar to the extracellular matrix of many tissues, can often be processed under relatively mild conditions, and may be delivered in a minimally invasive manner. This review will discuss recent advances in the field of injectable hydrogels, including both synthetic and native polymeric materials, which can be potentially used in cartilage and soft tissue engineering applications.

  8. Photocrosslinkable Gelatin Hydrogel for Epidermal Tissue Engineering.

    Science.gov (United States)

    Zhao, Xin; Lang, Qi; Yildirimer, Lara; Lin, Zhi Yuan; Cui, Wenguo; Annabi, Nasim; Ng, Kee Woei; Dokmeci, Mehmet R; Ghaemmaghami, Amir M; Khademhosseini, Ali

    2016-01-01

    Natural hydrogels are promising scaffolds to engineer epidermis. Currently, natural hydrogels used to support epidermal regeneration are mainly collagen- or gelatin-based, which mimic the natural dermal extracellular matrix but often suffer from insufficient and uncontrollable mechanical and degradation properties. In this study, a photocrosslinkable gelatin (i.e., gelatin methacrylamide (GelMA)) with tunable mechanical, degradation, and biological properties is used to engineer the epidermis for skin tissue engineering applications. The results reveal that the mechanical and degradation properties of the developed hydrogels can be readily modified by varying the hydrogel concentration, with elastic and compressive moduli tuned from a few kPa to a few hundred kPa, and the degradation times varied from a few days to several months. Additionally, hydrogels of all concentrations displayed excellent cell viability (>90%) with increasing cell adhesion and proliferation corresponding to increases in hydrogel concentrations. Furthermore, the hydrogels are found to support keratinocyte growth, differentiation, and stratification into a reconstructed multilayered epidermis with adequate barrier functions. The robust and tunable properties of GelMA hydrogels suggest that the keratinocyte laden hydrogels can be used as epidermal substitutes, wound dressings, or substrates to construct various in vitro skin models.

  9. WATERLESS DYEING [REVIEW

    Directory of Open Access Journals (Sweden)

    DEVRENT Nalan

    2015-05-01

    Full Text Available The textile industry is believed to be one of the biggest consumers of water. Water consumption and exhaustion in dyeing textile materials in conventional methods is an important environmental problem. The cost of waste water treatment will cause a prominent problem in the future as it does today. Increasing consideration of ecologic consequences of industrial processes as well as legislation enforcing the avoidance of environmental problems have caused a reorientation of thinking and promoted projects for replacement of conventional technologies. One of these new technologies is dyeing in supercritical fluids. Dyeing with supercritical carbon dioxide is a favourable concept considering the value of water as a natural resource and the cost of waste water treatment. This dyeing method offers many advantages over conventional aqueous dyeing: During this dyeing process no water is used, therefore there is no waste water problem, no other chemicals are required; the carbon dioxide can be recycled; the dystuff which is not adsorbed on the substrate can be collected and reused; The necessary energy consumption in this process is relatively lower than is needed to heat water in conventional methods of dyeing. Due to unnecessary of drying process, it helps to save both energy and time; and dyeing cycle is shorter compared with traditional methods. In addition carbon dioxide is non-toxic and non-flammable. Supercritical fluid, supercritical dyeing, disperse dyestuffs, solid-fluid equilibrium

  10. Iron oxide nanoparticle-micelles (ION-micelles for sensitive (molecular magnetic particle imaging and magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Lucas W E Starmans

    Full Text Available BACKGROUND: Iron oxide nanoparticles (IONs are a promising nanoplatform for contrast-enhanced MRI. Recently, magnetic particle imaging (MPI was introduced as a new imaging modality, which is able to directly visualize magnetic particles and could serve as a more sensitive and quantitative alternative to MRI. However, MPI requires magnetic particles with specific magnetic properties for optimal use. Current commercially available iron oxide formulations perform suboptimal in MPI, which is triggering research into optimized synthesis strategies. Most synthesis procedures aim at size control of iron oxide nanoparticles rather than control over the magnetic properties. In this study, we report on the synthesis, characterization and application of a novel ION platform for sensitive MPI and MRI. METHODS AND RESULTS: IONs were synthesized using a thermal-decomposition method and subsequently phase-transferred by encapsulation into lipidic micelles (ION-Micelles. Next, the material and magnetic properties of the ION-Micelles were analyzed. Most notably, vibrating sample magnetometry measurements showed that the effective magnetic core size of the IONs is 16 nm. In addition, magnetic particle spectrometry (MPS measurements were performed. MPS is essentially zero-dimensional MPI and therefore allows to probe the potential of iron oxide formulations for MPI. ION-Micelles induced up to 200 times higher signal in MPS measurements than commercially available iron oxide formulations (Endorem, Resovist and Sinerem and thus likely allow for significantly more sensitive MPI. In addition, the potential of the ION-Micelle platform for molecular MPI and MRI was showcased by MPS and MRI measurements of fibrin-binding peptide functionalized ION-Micelles (FibPep-ION-Micelles bound to blood clots. CONCLUSIONS: The presented data underlines the potential of the ION-Micelle nanoplatform for sensitive (molecular MPI and warrants further investigation of the FibPep-ION-Micelle

  11. Multicompartmental Microcapsules from Star Copolymer Micelles

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Ikjun; Malak, Sidney T.; Xu, Weinan; Heller, William T.; Tsitsilianis, Constantinos; Tsukruk, Vladimir V.

    2013-02-26

    We present the layer-by-layer (LbL) assembly of amphiphilic heteroarm pH-sensitive star-shaped polystyrene-poly(2-pyridine) (PSnP2VPn) block copolymers to fabricate porous and multicompartmental microcapsules. Pyridine-containing star molecules forming a hydrophobic core/hydrophilic corona unimolecular micelle in acidic solution (pH 3) were alternately deposited with oppositely charged linear sulfonated polystyrene (PSS), yielding microcapsules with LbL shells containing hydrophobic micelles. The surface morphology and internal nanopore structure of the hollow microcapsules were comparatively investigated for shells formed from star polymers with a different numbers of arms (9 versus 22) and varied shell thickness (5, 8, and 11 bilayers). The successful integration of star unimers into the LbL shells was demonstrated by probing their buildup, surface segregation behavior, and porosity. The larger arm star copolymer (22 arms) with stretched conformation showed a higher increment in shell thickness due to the effective ionic complexation whereas a compact, uniform grainy morphology was observed regardless of the number of deposition cycles and arm numbers. Small-angle neutron scattering (SANS) revealed that microcapsules with hydrophobic domains showed different fractal properties depending upon the number of bilayers with a surface fractal morphology observed for the thinnest shells and a mass fractal morphology for the completed shells formed with the larger number of bilayers. Moreover, SANS provides support for the presence of relatively large pores (about 25 nm across) for the thinnest shells as suggested from permeability experiments. The formation of robust microcapsules with nanoporous shells composed of a hydrophilic polyelectrolyte with a densely packed hydrophobic core based on star amphiphiles represents an intriguing and novel case of compartmentalized microcapsules with an ability to simultaneously store different hydrophilic, charged, and hydrophobic

  12. Adsorption of azo dyes on polymer materials

    Directory of Open Access Journals (Sweden)

    Panić Vesna V.

    2013-01-01

    Full Text Available The use of polymeric adsorbents for the removal of azo dyes from solution has been reviewed. Adsorption techniques are widely used to remove certain classes of pollutants from waters, especially those which are not easily biodegradable. The removal of azo dyes as pollutants from wastewaters of textile, paper, printing, leather, pharmaceutical and other industries has been addressed by the researchers. The wider use of already available adsorbents is restricted due to their high costs which lead to investigation and development of new materials that can be cheaper, eficient and easy regenerated. The aim of this article is to present to the readers the widespread investigations in recent years of synthetic and natural polymers as adsorbents and potential replacement of conventional adsorbents. This review presents only the data obtained using raw, hydrogel, grafted and crosslinked forms of synthetic and nature based polymers, and the discussion is limited to these polymer-based materials and their adsorption properties. [Projekat Ministarstva nauke Republike Srbije, br. 43009 i br. 172062.

  13. Encapsulation into complex coacervate core micelles promotes EGFP dimerization

    NARCIS (Netherlands)

    Nolles, A.; Dongen, Van N.J.E.; Westphal, A.H.; Visser, A.J.W.G.; Kleijn, J.M.; Berkel, Van W.J.H.; Borst, J.W.

    2017-01-01

    Complex coacervate core micelles (C3Ms) are colloidal structures useful for encapsulation of biomacromolecules. We previously demonstrated that enhanced green fluorescent protein (EGFP) can be encapsulated into C3Ms using the diblock copolymer

  14. Enantiomer separation by ultrafiltration of enantioselective micelles in multistage systems

    NARCIS (Netherlands)

    Overdevest, P.E.M.

    2000-01-01

    The Food and Bioprocess Engineering Group of Wageningen University, The Netherlands, is developing a new enantiomer separation system that is based on ultrafiltration (UF) of enantioselective micelles containing chiral selector molecules. Enantiomer molecules are optical isomers (mirror images), and

  15. Bundle Formation in Biomimetic Hydrogels.

    Science.gov (United States)

    Jaspers, Maarten; Pape, A C H; Voets, Ilja K; Rowan, Alan E; Portale, Giuseppe; Kouwer, Paul H J

    2016-08-08

    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and mechanical responsiveness through nonlinear mechanics, properties that are rarely observed in synthetic hydrogels. Using small-angle X-ray scattering (SAXS), we study the bundle formation and hydrogelation process of polyisocyanide gels, a synthetic material that uniquely mimics the structure and mechanics of biogels. We show how the structure of the material changes at the (thermally induced) gelation point and how factors such as concentration and polymer length determine the architecture, and with that, the mechanical properties. The correlation of the gel mechanics and the structural parameters obtained from SAXS experiments is essential in the design of future (synthetic) mimics of biopolymer networks.

  16. Fewer Bacteria Adhere to Softer Hydrogels

    Science.gov (United States)

    Kolewe, Kristopher W.; Peyton, Shelly R.; Schiffman, Jessica D.

    2015-01-01

    Clinically, biofilm-associated infections commonly form on intravascular catheters and other hydrogel surfaces. The overuse of antibiotics to treat these infections has led to the spread of antibiotic resistance and underscores the importance of developing alternative strategies that delay the onset of biofilm formation. Previously, it has been reported that during surface contact, bacteria can detect surfaces through subtle changes in the function of their motors. However, how the stiffness of a polymer hydrogel influences the initial attachment of bacteria is unknown. Systematically, we investigated poly(ethylene glycol) dimethacrylate (PEGDMA) and agar hydrogels that were twenty times thicker than the cumulative size of bacterial cell appendages, as a function of Young’s moduli. Soft (44.05 – 308.5 kPa), intermediate (1495 – 2877 kPa), and stiff (5152 – 6489 kPa) hydrogels were synthesized. Escherichia coli and Staphylococcus aureus attachment onto the hydrogels was analyzed using confocal microscopy after 2 and 24 hr incubation periods. Independent of hydrogel chemistry and incubation time, E. coli and S. aureus attachment correlated positively to increasing hydrogel stiffness. For example, after a 24 hr incubation period, there were 52% and 82% less E. coli adhered to soft PEGDMA hydrogels, than to the intermediate and stiff PEGDMA hydrogels, respectively. A 62% and 79% reduction in the area coverage by the Gram-positive microbe S. aureus occurred after 24 hr incubation on the soft versus intermediate and stiff PEGDMA hydrogels. We suggest that hydrogel stiffness is an easily tunable variable that, potentially, could be used synergistically with traditional antimicrobial strategies to reduce early bacterial adhesion, and therefore the occurrence of biofilm-associated infections. PMID:26291308

  17. Fewer Bacteria Adhere to Softer Hydrogels.

    Science.gov (United States)

    Kolewe, Kristopher W; Peyton, Shelly R; Schiffman, Jessica D

    2015-09-01

    Clinically, biofilm-associated infections commonly form on intravascular catheters and other hydrogel surfaces. The overuse of antibiotics to treat these infections has led to the spread of antibiotic resistance and underscores the importance of developing alternative strategies that delay the onset of biofilm formation. Previously, it has been reported that during surface contact, bacteria can detect surfaces through subtle changes in the function of their motors. However, how the stiffness of a polymer hydrogel influences the initial attachment of bacteria is unknown. Systematically, we investigated poly(ethylene glycol) dimethacrylate (PEGDMA) and agar hydrogels that were 20 times thicker than the cumulative size of bacterial cell appendages, as a function of Young's moduli. Soft (44.05-308.5 kPa), intermediate (1495-2877 kPa), and stiff (5152-6489 kPa) hydrogels were synthesized. Escherichia coli and Staphylococcus aureus attachment onto the hydrogels was analyzed using confocal microscopy after 2 and 24 h incubation periods. Independent of hydrogel chemistry and incubation time, E. coli and S. aureus attachment correlated positively to increasing hydrogel stiffness. For example, after a 24 h incubation period, there were 52 and 82% fewer E. coli adhered to soft PEGDMA hydrogels than to the intermediate and stiff PEGDMA hydrogels, respectively. A 62 and 79% reduction in the area coverage by the Gram-positive microbe S. aureus occurred after 24 h incubation on the soft versus intermediate and stiff PEGDMA hydrogels. We suggest that hydrogel stiffness is an easily tunable variable that could potentially be used synergistically with traditional antimicrobial strategies to reduce early bacterial adhesion and therefore the occurrence of biofilm-associated infections.

  18. A neutron scattering study of triblock copolymer micelles

    Energy Technology Data Exchange (ETDEWEB)

    Gerstenberg, M.C.

    1997-11-01

    The thesis describes the neutron scattering experiments performed on poly(ethylene oxide)/poly(propylene oxide)/poly(ethylene oxide) triblock copolymer micelles in aqueous solution. The studies concern the non-ionic triblock copolymer P85 which consists of two outer segments of 25 monomers of ethylene oxide attached to a central part of 40 monomers of propylene oxide. The amphiphilic character of P85 leads to formation of various structures in aqueous solution such as spherical micelles, rod-like structures, and a BCC liquid-crystal mesophase of spherical micelles. The present investigations are centered around the micellar structures. In the first part of this thesis a model for the micelle is developed for which an analytical scattering form factor can be calculated. The micelle is modeled as a solid sphere with tethered Gaussian chains. Good agreement was found between small-angle neutron scattering experiments and the form factor of the spherical P85 micelles. Above 60 deg. C some discrepancies were found between the model and the data which is possibly due to an elongation of the micelles. The second part focuses on the surface-induced ordering of the various micellar aggregates in the P85 concentration-temperature phase diagram. In the spherical micellar phase, neutron reflection measurements indicated a micellar ordering at the hydrophilic surface of quartz. Extensive modeling was performed based on a hard sphere description of the micellar interaction. By convolution of the distribution of hard spheres at a hard wall, obtained from Monte Carlo simulations, and the projected scattering length density of the micelle, a numerical expression was obtained which made it possible to fit the data. The hard-sphere-hard-wall model gave an excellent agreement in the bulk micellar phase. However, for higher concentrations (25 wt % P85) close to the transition from the micellar liquid into a micellar cubic phase, a discrepancy was found between the model and the

  19. Rheology and phase behavior of dense casein micelle dispersions

    Science.gov (United States)

    Bouchoux, A.; Debbou, B.; Gésan-Guiziou, G.; Famelart, M.-H.; Doublier, J.-L.; Cabane, B.

    2009-10-01

    Casein micelle dispersions have been concentrated through osmotic stress and examined through rheological experiments. In conditions where the casein micelles are separated from each other, i.e., below random-close packing, the dispersions have exactly the flow and dynamic properties of the polydisperse hard-sphere fluid, demonstrating that the micelles interact only through excluded volume effects in this regime. These interactions cause the viscosity and the elastic modulus to increase by three orders of magnitude approaching the concentration of random-close packing estimated at Cmax≈178 g/l. Above Cmax, the dispersions progressively turn into "gels" (i.e., soft solids) as C increases, with elastic moduli G' that are nearly frequency independent. In this second regime, the micelles deform and/or deswell as C increases, and the resistance to deformation results from the formation of bonds between micelles combined with the intrinsic mechanical resistance of the micelles. The variation in G' with C is then very similar to that observed with concentrated emulsions where the resistance to deformation originates from a set of membranes that separate the droplets. As in the case of emulsions, the G' values at high frequency are also nearly identical to the osmotic pressures required to compress the casein dispersions. The rheology of sodium caseinate dispersions in which the caseins are not structured into micelles is also reported. Such dispersions have the behavior of associative polymer solutions at all the concentrations investigated, further confirming the importance of structure in determining the rheological properties of casein micelle systems.

  20. Effects of copolymer component on the properties of phosphorylcholine micelles

    Directory of Open Access Journals (Sweden)

    Wu Z

    2017-01-01

    Full Text Available Zhengzhong Wu,1 Mengtan Cai,1 Jun Cao,2 Jiaxing Zhang,1 Xianglin Luo1,3 1College of Polymer Science and Engineering, 2National Engineering Research Center for Biomaterials, 3State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, People’s Republic of China Abstract: Zwitterionic polymers have unique features, such as good compatibility, and show promise in the application of drug delivery. In this study, the zwitterionic copolymers, poly(ε-caprolactone-b-poly(2-methacryloyloxyethyl phosphorylcholine with disulfide (PCL-ss-PMPC or poly(ε-caprolactone-b-poly(2-methacryloyloxyethyl phosphorylcholine or without disulfide (PCL-PMPC and with different block lengths in PCL-ss-PMPC, were designed. The designed copolymers were obtained by a combination of ring-opening polymerization and atom transferring radical polymerization. The crystallization properties of these polymers were investigated. The micelles were prepared based on the obtained copolymers with zwitterionic phosphorylcholine as the hydrophilic shell and PCL as the hydrophobic core. The size distributions of the blank micelles and the doxorubicin (DOX-loaded micelles were uniform, and the micelle diameters were <100 nm. In vitro drug release and intracellular drug release results showed that DOX-loaded PCL-ss-PMPC micelles could release drugs faster responding to the reduction condition and the intracellular microenvironment in contrast to PCL-PMPC micelles. Moreover, in vitro cytotoxicity evaluation revealed that the designed copolymers possessed low cell toxicity, and the inhibiting effect of DOX-loaded phosphorylcholine micelles to tumor cells was related to the components of these copolymers. These results reveal that the reduction-responsive phosphorylcholine micelles with a suitable ratio of hydrophilic/hydrophobic units can serve as promising drug carriers. Keywords: zwitterionic, reduction-sensitive, disulfide, phosphorylcholine

  1. Anaerobic azo dye reduction

    NARCIS (Netherlands)

    Zee, van der F.P.

    2002-01-01

    Azo dyes, aromatic moieties linked together by azo (-N=N-) chromophores, represent the largest class of dyes used in textile-processing and other industries. The release of these compounds into the environment is undesirable, not only because of their colour, but also because many azo

  2. Anaerobic azo dye reduction

    NARCIS (Netherlands)

    Zee, van der F.P.

    2002-01-01

    Azo dyes, aromatic moieties linked together by azo (-N=N-) chromophores, represent the largest class of dyes used in textile-processing and other industries. The release of these compounds into the environment is undesirable, not only because of their colour, but also b

  3. Bioprinting of 3D hydrogels.

    Science.gov (United States)

    Stanton, M M; Samitier, J; Sánchez, S

    2015-08-07

    Three-dimensional (3D) bioprinting has recently emerged as an extension of 3D material printing, by using biocompatible or cellular components to build structures in an additive, layer-by-layer methodology for encapsulation and culture of cells. These 3D systems allow for cell culture in a suspension for formation of highly organized tissue or controlled spatial orientation of cell environments. The in vitro 3D cellular environments simulate the complexity of an in vivo environment and natural extracellular matrices (ECM). This paper will focus on bioprinting utilizing hydrogels as 3D scaffolds. Hydrogels are advantageous for cell culture as they are highly permeable to cell culture media, nutrients, and waste products generated during metabolic cell processes. They have the ability to be fabricated in customized shapes with various material properties with dimensions at the micron scale. 3D hydrogels are a reliable method for biocompatible 3D printing and have applications in tissue engineering, drug screening, and organ on a chip models.

  4. Atomic Model and Micelle Dynamics of QS-21 Saponin

    Directory of Open Access Journals (Sweden)

    Conrado Pedebos

    2014-03-01

    Full Text Available QS-21 is a saponin extracted from Quillaja saponaria, widely investigated as a vaccine immunoadjuvant. However, QS-21 use is mainly limited by its chemical instability, significant variety in molecular composition and low tolerance dose in mammals. Also, this compound tends to form micelles in a concentration-dependent manner. Here, we aimed to characterize its conformation and the process of micelle formation, both experimentally and computationally. Therefore, molecular dynamics (MD simulations were performed in systems containing different numbers of QS-21 molecules in aqueous solution, in order to evaluate the spontaneous micelle formation. The applied methodology allowed the generation of micelles whose sizes were shown to be in high agreement with small-angle X-ray scattering (SAXS. Furthermore, the ester linkage between fucose and acyl chain was less solvated in the micellar form, suggesting a reduction in hydrolysis. This is the first atomistic interpretation of previous experimental data, the first micellar characterization of saponin micelles by SAXS and first tridimensional model of a micelle constituted of saponins, contributing to the understanding of the molecular basis of these compounds.

  5. Structure and stability of complex coacervate core micelles with lysozyme.

    Science.gov (United States)

    Lindhoud, Saskia; Vries, Renko de; Norde, Willem; Stuart, Martien A Cohen

    2007-07-01

    Encapsulation of enzymes by polymers is a promising method to influence their activity and stability. Here, we explore the use of complex coacervate core micelles for encapsulation of enzymes. The core of the micelles consists of negatively charged blocks of the diblock copolymer PAA42PAAm417 and the positively charged homopolymer PDMAEMA150. For encapsulation, part of the positively charged homopolymer was replaced by the positively charged globular protein lysozyme. We have studied the formation, structure, and stability of the resulting micelles for three different mixing ratios of homopolymer and lysozyme: a system predominantly consisting of homopolymer, a system predominantly consisting of lysozyme, and a system where the molar ratio between the two positively charged molecules was almost one. We also studied complexes made of only lysozyme and PAA42PAAm417. Complex formation and the salt-induced disintegration of the complexes were studied using dynamic light-scattering titrations. Small-angle neutron scattering was used to investigate the structures of the cores. We found that micelles predominantly consisting of homopolymer are spherical but that complex coacervate core micelles predominantly consisting of lysozyme are nonspherical. The stability of the micelles containing a larger fraction of lysozyme is lower.

  6. Evaluation of Photocrosslinked Lutrol Hydrogel for Tissue Printing Applications

    NARCIS (Netherlands)

    Fedorovich, Natalja E.; Swennen, Ives; Girones, Jordi; Moroni, Lorenzo; Blitterswijk, van Clemens A.; Schacht, Etienne; Alblas, Jacqueline; Dhert, Wouter J.A.

    2009-01-01

    Application of hydrogels in tissue engineering and innovative strategies such as organ printing, which is based on layered 3D deposition of cell-laden hydrogels, requires design of novel hydrogel matrices. Hydrogel demands for 3D printing include: 1) preservation of the printed shape after the depos

  7. Rapid Self-Integrating, Injectable Hydrogel for Tissue Complex Regeneration.

    Science.gov (United States)

    Hou, Sen; Wang, Xuefei; Park, Sean; Jin, Xiaobing; Ma, Peter X

    2015-07-15

    A novel rapid self-integrating, injectable, and bioerodible hydrogel is developed for bone-cartilage tissue complex regeneration. The hydrogels are able to self-integrate to form various structures, as can be seen after dying some hydrogel disks pink with rodamine. This hydrogel is demonstrated to engineer cartilage-bone complex.

  8. Evaluation of Photocrosslinked Lutrol Hydrogel for Tissue Printing applications

    NARCIS (Netherlands)

    Fedorovich, Natalja E.; Swennen, Ives; Girones, Jordi; Moroni, Lorenzo; van Blitterswijk, Clemens; Schacht, Etienne; Alblas, Jacqueline; Dhert, Wouter J.A.

    2009-01-01

    Application of hydrogels in tissue engineering and innovative strategies such as organ printing, which is based on layered 3D deposition of cell-laden hydrogels, requires design of novel hydrogel matrices. Hydrogel demands for 3D printing include: 1) preservation of the printed shape after the

  9. Switchable antimicrobial and antifouling hydrogels with enhanced mechanical properties.

    Science.gov (United States)

    Cao, Bin; Tang, Qiong; Li, Linlin; Humble, Jayson; Wu, Haiyan; Liu, Lingyun; Cheng, Gang

    2013-08-01

    New switchable hydrogels are developed. Under acidic conditions, hydrogels undergo self-cyclization and can catch and kill bacteria. Under neutral/basic conditions, hydrogels undergo ring-opening and can release killed bacterial cells and resist protein adsorption and bacterial attachment. Smart hydrogels also show a dramatically improved mechanical property, which is highly desired for biomedical applications.

  10. Systemic delivery of siRNA by actively targeted polyion complex micelles for silencing the E6 and E7 human papillomavirus oncogenes.

    Science.gov (United States)

    Nishida, Haruka; Matsumoto, Yoko; Kawana, Kei; Christie, R James; Naito, Mitsuru; Kim, Beob Soo; Toh, Kazuko; Min, Hyun Su; Yi, Yu; Matsumoto, Yu; Kim, Hyun Jin; Miyata, Kanjiro; Taguchi, Ayumi; Tomio, Kensuke; Yamashita, Aki; Inoue, Tomoko; Nakamura, Hiroe; Fujimoto, Asaha; Sato, Masakazu; Yoshida, Mitsuyo; Adachi, Katsuyuki; Arimoto, Takahide; Wada-Hiraike, Osamu; Oda, Katsutoshi; Nagamatsu, Takeshi; Nishiyama, Nobuhiro; Kataoka, Kazunori; Osuga, Yutaka; Fujii, Tomoyuki

    2016-06-10

    Human papillomavirus (HPV) E6 and E7 oncogenes are essential for the immortalization and maintenance of HPV-associated cancer and are ubiquitously expressed in cervical cancer lesions. Small interfering RNA (siRNA) coding for E6 and E7 oncogenes is a promising approach for precise treatment of cervical cancer, yet a delivery system is required for systemic delivery to solid tumors. Here, an actively targeted polyion complex (PIC) micelle was applied to deliver siRNAs coding for HPV E6/E7 to HPV cervical cancer cell tumors in immune-incompetent tumor-bearing mice. A cell viability assay revealed that both HPV type 16 and 18 E6/E7 siRNAs (si16E6/E7 and si18E6/E7, respectively) interfered with proliferation of cervical cancer cell lines in an HPV type-specific manner. A fluorescence imaging biodistribution analysis further revealed that fluorescence dye-labeled siRNA-loaded PIC micelles efficiently accumulated within the tumor mass after systemic administration. Ultimately, intravenous injection of si16E6/E7 and si18E6/E7-loaded PIC micelles was found to significantly suppress the growth of subcutaneous SiHa and HeLa tumors, respectively. The specific activity of siRNA treatment was confirmed by the observation that p53 protein expression was restored in the tumors excised from the mice treated with si16E6/E7- and si18E6/E7-loaded PIC micelles for SiHa and HeLa tumors, respectively. Therefore, the actively targeted PIC micelle incorporating HPV E6/E7-coding siRNAs demonstrated its therapeutic potential against HPV-associated cancer. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Hydrogels with Micellar Hydrophobic (Nano)Domains

    OpenAIRE

    Pekař, Miloslav

    2015-01-01

    Hydrogels containing hydrophobic domains or nanodomains, especially of the micellar type, are reviewed. Examples of the reasons for introducing hydrophobic domains into hydrophilic gels are given; typology of these materials is introduced. Synthesis routes are exemplified and properties of a variety of such hydrogels in relation with their intended applications are described. Future research needs are identified briefly.

  12. Hydrogels with micellar hydrophobic (nano)domains

    OpenAIRE

    Miloslav ePekař

    2015-01-01

    Hydrogels containing hydrophobic domains or nanodomains, especially of the micellar type, are reviewed. Examples of the reasons for introducing hydrophobic domains into hydrophilic gels are given; typology of these materials is introduced. Synthesis routes are exemplified and properties of a variety of such hydrogels in relation with their intended applications are described. Future research needs are identified briefly.

  13. Flexible hydrogel-based functional composite materials

    Science.gov (United States)

    Song, Jie; Saiz, Eduardo; Bertozzi, Carolyn R; Tomasia, Antoni P

    2013-10-08

    A composite having a flexible hydrogel polymer formed by mixing an organic phase with an inorganic composition, the organic phase selected from the group consisting of a hydrogel monomer, a crosslinker, a radical initiator, and/or a solvent. A polymerization mixture is formed and polymerized into a desired shape and size.

  14. Impermeable Robust Hydrogels via Hybrid Lamination.

    Science.gov (United States)

    Parada, German A; Yuk, Hyunwoo; Liu, Xinyue; Hsieh, Alex J; Zhao, Xuanhe

    2017-07-17

    Hydrogels have been proposed for sensing, drug delivery, and soft robotics applications, yet most of these materials suffer from low mechanical robustness and high permeability to small molecules, limiting their widespread use. This study reports a general strategy and versatile method to fabricate robust, highly stretchable, and impermeable hydrogel laminates via hybrid lamination of an elastomer layer bonded between hydrogel layers. By controlling the layers' composition and thickness, it is possible to tune the stiffness of the impermeable hydrogels without sacrificing the stretchability. These hydrogel laminates exhibit ultralow surface coefficients of friction and, unlike common single-material hydrogels, do not allow diffusion of various molecules across the structure due to the presence of the elastomer layer. This feature is then used to release different model drugs and, in a subsequent experiment, to sense different pH conditions on the two sides of the hydrogel laminate. A potential healthcare application is shown using the presented method to coat medical devices (catheter, tubing, and condom) with hydrogel, to allow for drug release and sensing of environmental conditions for gastrointestinal or urinary tract. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Photopatterning of hydrogel microarryas in closed microchips

    NARCIS (Netherlands)

    Gümüscü, B.; Bomer, Johan G.; van den Berg, Albert; Eijkel, Jan C.T.

    2015-01-01

    To date, optical lithography has been extensively used for in situ patterning of hydrogel structures in a scale range from hundreds of microns to a few millimeters. The two main limitations which prevent smaller feature sizes of hydrogel structures are (1) the upper glass layer of a microchip

  16. Hydrogels with micellar hydrophobic (nano)domains

    Science.gov (United States)

    Pekař, Miloslav

    2014-12-01

    Hydrogels containing hydrophobic domains or nanodomains, especially of the micellar type, are reviewed. Examples of the reasons for introducing hydrophobic domains into hydrophilic gels are given; typology of these materials is introduced. Synthesis routes are exemplified and properties of a variety of such hydrogels in relation with their intended applications are described. Future research needs are identified briefly.

  17. Photopatterning of hydrogel microarryas in closed microchips

    NARCIS (Netherlands)

    Gumuscu, Burcu; Bomer, Johan G.; Berg, van den Albert; Eijkel, Jan C.T.

    2015-01-01

    To date, optical lithography has been extensively used for in situ patterning of hydrogel structures in a scale range from hundreds of microns to a few millimeters. The two main limitations which prevent smaller feature sizes of hydrogel structures are (1) the upper glass layer of a microchip mainta

  18. Design of Hydrogels for Biomedical Applications.

    Science.gov (United States)

    Kamata, Hiroyuki; Li, Xiang; Chung, Ung-Il; Sakai, Takamasa

    2015-11-18

    Hydrogels are considered key tools for the design of biomaterials, such as wound dressings, drug reservoirs, and temporary scaffolds for cells. Despite their potential, conventional hydrogels have limited applicability under wet physiological conditions because they suffer from the uncontrollable temporal change in shape: swelling takes place immediately after the installation. Swollen hydrogels easily fail under mechanical stress. The morphological change may cause not only the slippage from the installation site but also local nerve compression. The design of hydrogels that can retain their original shape and mechanical properties in an aqueous environment is, therefore, of great importance. On the one hand, the controlled degradation of used hydrogels has to be realized in some biomedical applications. This Progress Report provides a brief overview of the recent progress in the development of hydrogels for biomedical applications. Practical approaches to control the swelling properties of hydrogels are discussed. The designs of hydrogels with controlled degradation properties as well as the theoretical models to predict the degradation behavior are also introduced. Moreover, current challenges and limitation toward biomedical applications are discussed, and future directions are offered.

  19. Soy-based Hydrogels for Biomedical Applications

    Science.gov (United States)

    Soy based hydrogels were prepared by ring-opening polymerization of epoxidized soybean oil, following hydrolysis of formed polymers. The hydrogels were evaluated loading and releasing water-soluble anticancer drug doxorubin (Dox). The results suggest that this new system offers a great potential t...

  20. Cellulose/polyvinyl alcohol-based hydrogels for reconfigurable lens

    Science.gov (United States)

    Jayaramudu, T.; Ko, Hyun-U.; Gao, Xiaoyuan; Li, Yaguang; Kim, Sang Youn; Kim, Jaehwan

    2016-04-01

    Electroactive hydrogels are attractive for soft robotics and reconfigurable lens applications. Here we describe the design and fabrication of cellulose-poly vinyl alcohol based hydrogels. The fabricated hydrogels were confirmed by Fourier transformer spectroscopy, swelling studies, thermal analysis, surface morphology of fabricated hydrogel was study by using scanning electron microscopy. The effect of poly vinyl alcohol concentration on the optical and electrical behavior of hydrogels was studied.

  1. Micelles and reverse micelles in the nickel bis(2-ethylhexyl) sulfosuccinate/water/isooctane microemulsion.

    Science.gov (United States)

    Garza, Cristina; Carbajal-Tinoco, Mauricio D; Castillo, Rolando

    2004-12-01

    The ternary system Ni(2+)(AOT)(2) (nickel 2-bis[2-ethylhexyl] sulfosuccinate)/water/isooctane presents w/o and o/w microemulsions with a Winsor progression (2Phi-3Phi-2Phi), without the addition of salt; the "fish diagram" was obtained for alpha=0.5 and gamma=0.02-0.22. Using static and dynamic light scattering the micellar size, the ratio of water to surfactant, and the density of micelles for this system were estimated. In addition, the mean interfacial curvature as a function of temperature was obtained.

  2. Determining Compatibilities of Reactive Dyes in Pad Dyeing

    Institute of Scientific and Technical Information of China (English)

    屠天民

    2001-01-01

    Compatibilities of reactive dyes were conventionally shown by exhausting curves. But the change of proportion of dyes in padding dyebath was difficult for pad dyeing to be described by these curves. In this paper, a kind of simulation of pad dyeing process was used to determine dyestuff compatibility in pad dyeing for ramie and linen fabrics. Seven reactive dyes were divided into three groups and tested., The group with Cibacron Yellow C - 2R, Red C - R, and Blue C - R showed very good compatibility both for ramie and linen,and the other two groups of dyes gave out correspondingly low compatibilities in the pad dyeing tests. The results of the method for determining the compatibility of dyes displayed good consistency with the actul pad dyeing process.

  3. Surface induced ordering of micelles at the solid-liquid interface

    DEFF Research Database (Denmark)

    Gerstenberg, M.C.; Pedersen, J.S.; Smith, G.S.

    1998-01-01

    The surface induced ordering of triblock copolymer micelles in aqueous solution was measured with neutron reflectivity far above the critical micelle concentration. The scattering length density profiles showed a clear indication of ordered layers of micelles perpendicular to a quartz surface....... The structure and interactions of the micelles were modeled in detail. The convolution of the center distribution of the micelles, obtained from Monte Carlo simulations of hard spheres at a hard wall, and the projected density of the micelle showed excellent agreement with the experimental profiles. [S1063-651X...

  4. The capture and stabilization of curcumin using hydrophobically modified polyacrylate aggregates and hydrogels.

    Science.gov (United States)

    Harada, Takaaki; Pham, Duc-Truc; Lincoln, Stephen F; Kee, Tak W

    2014-08-07

    Hydrophobically modified polyacrylates are shown to suppress the degradation of the medicinal pigment curcumin under physiological conditions. In aqueous solution, the 3% octadecyl randomly substituted polyacrylate, PAAC18, forms micelle-like aggregates at a concentration of 1 wt %. Under both conditions, PAAC18 shows a remarkable ability to suppress the degradation of curcumin at pH 7.4 and 37 °C such that its degradation half-life is increased by 1600-2000-fold. The suppression of degradation is attributed to hydrophobic interactions between curcumin and the octadecyl substituents of PAAC18 within the micelle-like aggregates and the hydrogel, as indicated by 2D NOESY (1)H NMR spectroscopy. UV-visible absorption titration results are consistent with the interaction of curcumin with five octadecyl substituents on average, which appears to substantially exclude water and greatly decrease the curcumin degradation rate. Dynamic light scattering and zeta potential measurements show the average hydrodynamic diameters of the PAAC18 aggregates to be 0.86-1.15 μm with a negative surface charge. In contrast to the octadecyl substitution, the 3% dodecyl randomly substituted polyacrylate, PAAC12, shows a negligible effect on slowing the degradation of curcumin, consistent with the dodecyl substituents being insufficiently long to capture curcumin in a adequately hydrophobic environment. These observations indicate the potential for PAAC18 to act as a model drug delivery system.

  5. Thermoresponsive cellulose ether and its flocculation behavior for organic dye removal.

    Science.gov (United States)

    Tian, Ye; Ju, Benzhi; Zhang, Shufen; Hou, Linan

    2016-01-20

    A thermoresponsive polymer, 2-hydroxy-3-butoxypropyl hydroxyethyl cellulose (HBPEC), was prepared by grafting butyl glycidyl ether (BGE) onto hydroxyethyl cellulose (HEC). The lower critical solution temperature (LCST) and critical flocculation temperature (CFT) of HBPEC were varied by changing the molar substitution (MS) and salt concentrations. Transmission electron microscopy (TEM) images and fluorescence spectroscopy showed that HBPEC can assemble into micelles. Additionally, using Nile Red as a model dye, the performance of HBPEC for the removing Nile Red from aqueous solutions via cloud point extraction procedures was investigated in detail. The encapsulation behavior of dye in the aqueous solution of HBPEC was studied by fluorescence spectroscopy and fluorescence microscope. The experimental results indicated that 99.4% of dye was removed from the aqueous solutions, and the HBPEC was recycled and reused easily, Furthermore, the recycle efficiency (RE) and maximum loading capacity portrayed little loss with the number of cycles.

  6. Analysis of the solvatochromic behavior of the disubstituted triphenylmethane dye brilliant green.

    Science.gov (United States)

    Karukstis, K K; Gulledge, A V

    1998-10-01

    The coincident spectral components of the main visible absorption band of the triphenylmethane dye Brilliant Green can be resolved using a nonlinear least-squares fitting routine. This analysis reveals two Gaussian components, with centers near 600 and 630 nm, that possess additional spectral characteristics with a pronounced sensitivity to the dye's microenvironment. In particular, both the ratio of the heights of these Gaussian peaks and the ratio of their areas exhibit an inverted dependence on solvent dielectric constant, i.e., a reversal of solvatochromic behavior in media of low polarity. Such an absorption spectrum analysis facilitates the use of triphenylmethane dyes that lack symmetric trisubstitution of the phenyl rings as environment-sensitive spectroscopic probes. We demonstrate further the utility of this approach through the spectrophotometric determination of the critical micelle concentration of the anionic surfactant sodium dodecyl sulfate using Brilliant Green as an optical probe.

  7. Unsymmetrical Heptamethine Dyes for NIR Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Thomas Geiger

    2014-01-01

    Full Text Available Seven unsymmetrical heptamethine dyes with carboxylic acid functionality were synthesized and characterized. These near-infrared dyes exhibit outstanding photophysical properties depending on their heterocyclic moieties and molecular structure. As proof of principle, the dyes were used as photosensitizers in dye-sensitized solar cells. Using the most promising dye, an overall conversion efficiency of 1.22% and an almost colorless solar cell were achieved.

  8. Poloxamer-based binary hydrogels for delivering tramadol hydrochloride: sol-gel transition studies, dissolution-release kinetics, in vitro toxicity, and pharmacological evaluation

    Science.gov (United States)

    dos Santos, Ana Claudia Mendonça; Akkari, Alessandra Cristina Santos; Ferreira, Iasmin Rosanne Silva; Maruyama, Cintia Rodrigues; Pascoli, Monica; Guilherme, Viviane Aparecida; de Paula, Eneida; Fraceto, Leonardo Fernandes; de Lima, Renata; Melo, Patrícia da Silva; de Araujo, Daniele Ribeiro

    2015-01-01

    In this work, poloxamer (PL)-based binary hydrogels, composed of PL 407 and PL 188, were studied with regard to the physicochemical aspects of sol-gel transition and pharmaceutical formulation issues such as dissolution-release profiles. In particular, we evaluated the cytotoxicity, genotoxicity, and in vivo pharmacological performance of PL 407 and PL 407–PL 188 hydrogels containing tramadol (TR) to analyze its potential treatment of acute pain. Drug–micelle interaction studies showed the formation of PL 407–PL 188 binary systems and the drug partitioning into the micelles. Characterization of the sol-gel transition phase showed an increase on enthalpy variation values that were induced by the presence of TR hydrochloride within the PL 407 or PL 407–PL 188 systems. Hydrogel dissolution occurred rapidly, with approximately 30%–45% of the gel dissolved, reaching ~80%–90% up to 24 hours. For in vitro release assays, formulations followed the diffusion Higuchi model and lower Krel values were observed for PL 407 (20%, Krel =112.9±10.6 μg·h−1/2) and its binary systems PL 407–PL 188 (25%–5% and 25%–10%, Krel =80.8±6.1 and 103.4±8.3 μg·h−1/2, respectively) in relation to TR solution (Krel =417.9±47.5 μg·h−1/2, P72 hours) pointed to PL-based hydrogels as a potential treatment, by subcutaneous injection, for acute pain. PMID:25848258

  9. Spectroscopic Manifestation of Dye Pair Interactions at High Concentrations in structurally organized SiO2 Films

    CERN Document Server

    Tikhonov, E A

    2010-01-01

    Concentration spectral manifestation of the ionic and neutral dyes encapsulated in mesoporous silicate films was studied. The mesoporous dyed SiO2 film was prepared by sol-gel technology with use as surfactant the amphiphilic three-bloc copolymer Pluronic P123. It was discovered when dye concentration exceeds mesoporous one the new spectral bands appear that are distinct from the initial monomolecular predecessors. To explain the phenomena guess is formulated and proved that origin of new spectrums is obliged to formation of the ionic pairs, excimers and excitons with participation of dye molecules localized in the characteristic places of mesoporous silicate film. Key terms: mesoporous silicate film, polymer micelles, dye fluorescence, excimers, ionic pair

  10. Dyeing of Polyester with Disperse Dyes: Part 2. Synthesis and Dyeing Characteristics of Some Azo Disperse Dyes for Polyester Fabrics

    Directory of Open Access Journals (Sweden)

    Alya M. Al-Etaibi

    2016-06-01

    Full Text Available The goal of this study was to utilize carrier for accelerating the rate of dyeing not only to enhance dyeing of polyester fabrics dyed with disperse dyes 3a,b, but also to save energy. Both the color strength expressed as dye uptake and the fastness properties of the dyed fabrics were evaluated.

  11. Fong's: Saving Water in Dyeing

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    @@ In an effort to save the precious water resource and reduce the environmental impact, Fong's Industries Group along with its member companies, namely "Fong's National", "THEN", "Goller" and "Fong's Water Technology" provide an ecological dyeing solution to reduce the water consumption drastically through their innovative technologies covering the processes from yarn dyeing to piece dyeing and recycling of discharge after dyeing and finishing.

  12. Hydrogels of sodium alginate in cationic surfactants: Surfactant dependent modulation of encapsulation/release toward Ibuprofen.

    Science.gov (United States)

    Jabeen, Suraya; Chat, Oyais Ahmad; Maswal, Masrat; Ashraf, Uzma; Rather, Ghulam Mohammad; Dar, Aijaz Ahmad

    2015-11-20

    The interaction of cetyltrimethylammoium bromide (CTAB) and its gemini homologue (butanediyl-1,4-bis (dimethylcetylammonium bromide), 16-4-16 with biocompatible polymer sodium alginate (SA) has been investigated in aqueous medium. Addition of K2CO3 influences viscoelastic properties of surfactant impregnated SA via competition between electrostatic and hydrophobic interactions. Viscosity of these polymer-surfactant systems increases with increase in concentration of K2CO3, and a cryogel is formed at about 0.5M K2CO3 concentration. The thermal stability of gel (5% SA+0.5M K2CO3) decreases with increase in surfactant concentration, a minimum is observed with increase in 16-4-16 concentration. The impact of surfactant addition on the alginate structure vis-à-vis its drug loading capability and release thereof was studied using Ibuprofen (IBU) as the model drug. The hydrogel with 16-4-16 exhibits higher IBU encapsulation and faster release in comparison to the one containing CTAB. This higher encapsulation-cum-faster release capability has been related to micelle mediated solubilization and greater porosity of the hydrogel with gemini surfactant.

  13. Diode-pumped dye laser

    Science.gov (United States)

    Burdukova, O. A.; Gorbunkov, M. V.; Petukhov, V. A.; Semenov, M. A.

    2016-10-01

    This letter reports diode pumping for dye lasers. We offer a pulsed dye laser with an astigmatism-compensated three-mirror cavity and side pumping by blue laser diodes with 200 ns pulse duration. Eight dyes were tested. Four dyes provided a slope efficiency of more than 10% and the highest slope efficiency (18%) was obtained for laser dye Coumarin 540A in benzyl alcohol.

  14. Orthogonal Enzymatic Reactions to Control Supramolecular Hydrogelations%Orthogonal Enzymatic Reactions to Control Supramolecular Hydrogelations

    Institute of Scientific and Technical Information of China (English)

    陈国钦; 任春华; 王玲; 徐兵; 杨志谋

    2012-01-01

    Enzyme-responsive hydrogels have great potential in applications of controlled drug release, tissue engineering, etc. In this study, we reported on a supramolecular hydrogel that showed responses to two enzymes, phosphatase which was used to form the hydrogels and esterase which could trigger gelsol phase transitions. The gelation process and visco-elasticity property of the resulting gel, morphology of the nanostructures in hydrogel, and peptide conformation in the self-assembled nanostructure were characterized by theology, transmission electron microscope (TEM), and circular dichroism (CD), respectively. Potential application of the enzyme-responsive hydrogel in drug release was also demonstrated in this study. Though only one potential application of drug release was proved in this study, the responsive hydrogel system in this study might have potentials for the applications in fields of cell culture, controlled-drug release, etc.

  15. Extraction of dye

    African Journals Online (AJOL)

    ... Uganda is a home of thousands of largely unknown and undocumented plants. ... Dyes of natural origins are great for color appreciation as any variation in the ... Asteraceae characterized by bitter leaves, traditionally used for treating fever.

  16. Designing hydrogels for controlled drug delivery

    Science.gov (United States)

    Li, Jianyu; Mooney, David J.

    2016-12-01

    Hydrogel delivery systems can leverage therapeutically beneficial outcomes of drug delivery and have found clinical use. Hydrogels can provide spatial and temporal control over the release of various therapeutic agents, including small-molecule drugs, macromolecular drugs and cells. Owing to their tunable physical properties, controllable degradability and capability to protect labile drugs from degradation, hydrogels serve as a platform on which various physiochemical interactions with the encapsulated drugs occur to control drug release. In this Review, we cover multiscale mechanisms underlying the design of hydrogel drug delivery systems, focusing on physical and chemical properties of the hydrogel network and the hydrogel-drug interactions across the network, mesh and molecular (or atomistic) scales. We discuss how different mechanisms interact and can be integrated to exert fine control in time and space over drug presentation. We also collect experimental release data from the literature, review clinical translation to date of these systems and present quantitative comparisons between different systems to provide guidelines for the rational design of hydrogel delivery systems.

  17. RF-interrogatable hydrogel-actuated biosensor

    Energy Technology Data Exchange (ETDEWEB)

    Hoel, Z; Wang, A W; Darrow, C B; Lee, A P; McConaghy, C F; Krulevitch, P; Gilman, A; Satcher, J H; Lane, S M

    2000-01-10

    The authors present a novel micromachined sensor that couples a swellable hydrogel with capacitive detection. The hydrogel swells in response to analyte concentration, exerting contact pressure on a deformable conducting membrane. Results are presented for characterization of a PHEMA hydrogel swelling in response to a calcium nitrate solution. Pressure-deflection measurements are performed on NiTi-based membranes. Hydrogel-actuated deflections of the membranes are measured. These measurements are correlated to determine the pressure generating characteristics of the hydrogel. Membrane deflection techniques have not previously been employed for hydrogel characterization. The PHEMA sample exhibited greatest sensitivity in the pH range of 6.0--6.5 and performed an average of 2.8 Joules of work per m{sup 3} per pH unit in response to ambient conditions over the pH range 3.5--6.5. The membrane deflections correspond to capacitive shifts of about 4 pF per pH unit for a capacitive transducer with initial gap of 100 {micro}m, capacitor plate area of 18.5 mm{sup 2} , and initial hydrogel volume of 11 {micro}L.

  18. Applications of polymeric micelles with tumor targeted in chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ding Hui; Wang Xiaojun; Zhang Song; Liu Xinli, E-mail: Vip.lxl@163.com [Shandong Polytechnic University, Shandong Provincial Key Laboratory of Microbial Engineering (China)

    2012-11-15

    Polymeric micelles (PMs) have gained more progress as a carrier system with the quick development of biological and nanoparticle techniques. In particular, PMs with smart targeting can deliver anti-cancer drugs directly into tumor cells at a sustained rate. PMs with core-shell structure (with diameters of 10 {approx} 100 nm) have been prepared by a variety of biodegradable and biocompatible polymers via a self-assembly process. The preparation of polymeric micelles with stimuli-responsive block copolymers or modification of target molecules on polymeric micelles' surface are able to significantly improve the efficiency of drug delivery. Polymeric micelles, which have been considered as a novel promising drug carrier for cancer therapeutics, are rapidly evolving and being introduced in an attempt to overcome several limitations of traditional chemotherapeutics, including water solubility, tumor-specific accumulation, anti-tumor efficacy, and non-specific toxicity. This review describes the preparation of polymeric micelles and the targeted modification which greatly enhance the effects of chemotherapeutic agents.

  19. Stability of complex coacervate core micelles containing metal coordination polymer.

    Science.gov (United States)

    Yan, Yun; de Keizer, Arie; Cohen Stuart, Martien A; Drechsler, Markus; Besseling, Nicolaas A M

    2008-09-01

    We report on the stability of complex coacervate core micelles, i.e., C3Ms (or PIC, BIC micelles), containing metal coordination polymers. In aqueous solutions these micelles are formed between charged-neutral diblock copolymers and oppositely charged coordination polymers formed from metal ions and bisligand molecules. The influence of added salt, polymer concentration, and charge composition was investigated by using light scattering and cryo-TEM techniques. The scattering intensity decreases strongly with increasing salt concentration until a critical salt concentration beyond which no micelles exist. The critical micelle concentration increases almost exponentially with the salt concentration. From the scattering results it follows that the aggregation number decreases with the square root of the salt concentration, but the hydrodynamic radius remains constant or increases slightly. It was concluded that the density of the core decreases with increasing ionic strength. This is in agreement with theoretical predictions and is also confirmed by cryo-TEM measurements. A complete composition diagram was constructed based on the composition boundaries obtained from light scattering titrations.

  20. Photopatterning of Hydrogel Microarrays in Closed Microchips.

    Science.gov (United States)

    Gumuscu, Burcu; Bomer, Johan G; van den Berg, Albert; Eijkel, Jan C T

    2015-12-14

    To date, optical lithography has been extensively used for in situ patterning of hydrogel structures in a scale range from hundreds of microns to a few millimeters. The two main limitations which prevent smaller feature sizes of hydrogel structures are (1) the upper glass layer of a microchip maintains a large spacing (typically 525 μm) between the photomask and hydrogel precursor, leading to diffraction of UV light at the edges of mask patterns, (2) diffusion of free radicals and monomers results in irregular polymerization near the illumination interface. In this work, we present a simple approach to enable the use of optical lithography to fabricate hydrogel arrays with a minimum feature size of 4 μm inside closed microchips. To achieve this, we combined two different techniques. First, the upper glass layer of the microchip was thinned by mechanical polishing to reduce the spacing between the photomask and hydrogel precursor, and thereby the diffraction of UV light at the edges of mask patterns. The polishing process reduces the upper layer thickness from ∼525 to ∼100 μm, and the mean surface roughness from 20 to 3 nm. Second, we developed an intermittent illumination technique consisting of short illumination periods followed by relatively longer dark periods, which decrease the diffusion of monomers. Combination of these two methods allows for fabrication of 0.4 × 10(6) sub-10 μm sized hydrogel patterns over large areas (cm(2)) with high reproducibility (∼98.5% patterning success). The patterning method is tested with two different types of photopolymerizing hydrogels: polyacrylamide and polyethylene glycol diacrylate. This method enables in situ fabrication of well-defined hydrogel patterns and presents a simple approach to fabricate 3-D hydrogel matrices for biomolecule separation, biosensing, tissue engineering, and immobilized protein microarray applications.

  1. The matrix reloaded: the evolution of regenerative hydrogels

    Directory of Open Access Journals (Sweden)

    Esmaiel Jabbari

    2016-05-01

    Full Text Available Cell-laden hydrogels can regenerate lost, damaged or malfunctioning tissues. Clinical success of such hydrogels is strongly dependent on the ability to tune their chemical, physico-mechanical, and biological properties to a specific application. In particular, mimicking the intricate arrangement of cell-interactive ligands of natural tissues is crucial to proper tissue function. Natural extracellular matrix elements represent a unique source for generating such interactions. A plethora of extracellular matrix-based approaches have been explored to augment the regenerative potential of hydrogels. These efforts include the development of matrix-like hydrogels, hydrogels containing matrix-like molecules, hydrogels containing decellularized matrix, hydrogels derived from decellularized matrix, and decellularized tissues as reimplantable matrix hydrogels. Here we review the evolution, strengths and weaknesses of these developments from the perspective of creating tissue regenerating hydrogels.

  2. Electrochemical Hydrogel Lithography of Calcium-Alginate Hydrogels for Cell Culture

    Directory of Open Access Journals (Sweden)

    Fumisato Ozawa

    2016-08-01

    Full Text Available Here we propose a novel electrochemical lithography methodology for fabricating calcium-alginate hydrogels having controlled shapes. We separated the chambers for Ca2+ production and gel formation with alginate with a semipermeable membrane. Ca2+ formed in the production chamber permeated through the membrane to fabricate a gel structure on the membrane in the gel formation chamber. When the calcium-alginate hydrogels were modified with collagen, HepG2 cells proliferated on the hydrogels. These results show that electrochemical hydrogel lithography is useful for cell culture.

  3. 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.

  4. Dye Application, Manufacture of Dye Intermediates and Dyes

    Science.gov (United States)

    Freeman, H. S.; Mock, G. N.

    It is difficult if not impossible to determine when mankind first systematically applied color to a textile substrate. The first colored fabrics were probably nonwoven felts painted in imitation of animal skins. The first dyeings were probably actually little more than stains from the juice of berries. Ancient Greek writers described painted fabrics worn by the tribes of Asia Minor. But just where did the ancient craft have its origins? Was there one original birthplace or were there a number of simultaneous beginnings around the world?

  5. Biomimetic oral mucin from polymer micelle networks

    Science.gov (United States)

    Authimoolam, Sundar Prasanth

    Mucin networks are formed by the complexation of bottlebrush-like mucin glycoprotein with other small molecule glycoproteins. These glycoproteins create nanoscale strands that then arrange into a nanoporous mesh. These networks play an important role in ensuring surface hydration, lubricity and barrier protection. In order to understand the functional behavior in mucin networks, it is important to decouple their chemical and physical effects responsible for generating the fundamental property-function relationship. To achieve this goal, we propose to develop a synthetic biomimetic mucin using a layer-by-layer (LBL) deposition approach. In this work, a hierarchical 3-dimensional structures resembling natural mucin networks was generated using affinity-based interactions on synthetic and biological surfaces. Unlike conventional polyelectrolyte-based LBL methods, pre-assembled biotin-functionalized filamentous (worm-like) micelles was utilized as the network building block, which from complementary additions of streptavidin generated synthetic networks of desired thickness. The biomimetic nature in those synthetic networks are studied by evaluating its structural and bio-functional properties. Structurally, synthetic networks formed a nanoporous mesh. The networks demonstrated excellent surface hydration property and were able capable of microbial capture. Those functional properties are akin to that of natural mucin networks. Further, the role of synthetic mucin as a drug delivery vehicle, capable of providing localized and tunable release was demonstrated. By incorporating antibacterial curcumin drug loading within synthetic networks, bacterial growth inhibition was also demonstrated. Thus, such bioactive interfaces can serve as a model for independently characterizing mucin network properties and through its role as a drug carrier vehicle it presents exciting future opportunities for localized drug delivery, in regenerative applications and as bio

  6. Mixed micelles of 7,12-dioxolithocholic acid and selected hydrophobic bile acids: interaction parameter, partition coefficient of nitrazepam and mixed micelles haemolytic potential.

    Science.gov (United States)

    Poša, Mihalj; Tepavčević, Vesna

    2011-09-01

    The formation of mixed micelles built of 7,12-dioxolithocholic and the following hydrophobic bile acids was examined by conductometric method: cholic (C), deoxycholic (D), chenodeoxycholic (CD), 12-oxolithocholic (12-oxoL), 7-oxolithocholic (7-oxoL), ursodeoxycholic (UD) and hiodeoxycholic (HD). Interaction parameter (β) in the studied binary mixed micelles had negative value, suggesting synergism between micelle building units. Based on β value, the hydrophobic bile acids formed two groups: group I (C, D and CD) and group II (12-oxoL, 7-oxoL, UD and HD). Bile acids from group II had more negative β values than bile acids from group I. Also, bile acids from group II formed intermolecular hydrogen bonds in aggregates with both smaller (2) and higher (4) aggregation numbers, according to the analysis of their stereochemical (conformational) structures and possible structures of mixed micelles built of these bile acids and 7,12-dioxolithocholic acid. Haemolytic potential and partition coefficient of nitrazepam were higher in mixed micelles built of the more hydrophobic bile acids (C, D, CD) and 7,12-dioxolithocholic acid than in micelles built only of 7,12-dioxolithocholic acid. On the other hand, these mixed micelles still had lower values of haemolytic potential than micelles built of C, D or CD. The mixed micelles that included bile acids: 12-oxoL, 7-oxoL, UD or HD did not significantly differ from the micelles of 7,12-dioxolithocholic acid, observing the values of their haemolytic potential.

  7. Artificial Self-Sufficient P450 in Reversed Micelles

    Directory of Open Access Journals (Sweden)

    Teruyuki Nagamune

    2010-04-01

    Full Text Available Cytochrome P450s are heme-containing monooxygenases that require electron transfer proteins for their catalytic activities. They prefer hydrophobic compounds as substrates and it is, therefore, desirable to perform their reactions in non-aqueous media. Reversed micelles can stably encapsulate proteins in nano-scaled water pools in organic solvents. However, in the reversed micellar system, when multiple proteins are involved in a reaction they can be separated into different micelles and it is then difficult to transfer electrons between proteins. We show here that an artificial self-sufficient cytochrome P450, which is an enzymatically crosslinked fusion protein composed of P450 and electron transfer proteins, showed micelle-size dependent catalytic activity in a reversed micellar system. Furthermore, the presence of thermostable alcohol dehydrogenase promoted the P450-catalyzed reaction due to cofactor regeneration.

  8. Multicompartment Micelles From π-Shaped ABC Block Copolymers

    Institute of Scientific and Technical Information of China (English)

    XIA Jun; ZHONG Chong-Li

    2007-01-01

    Dissipative particle dynamics simulations were performed on the morphology and structure of multicompartment micelles formed from n-shaped ABC block copolymers in water. The influences of chain architectures were studied in a systematic way, and a rich variety of morphologies were observed, such as spherical, wormlike,X-shaped, Y-shaped, ribbon-like, layered rod-like, layered disk-like, as well as network morphologies. The simulations show that the distance between the two grafts plays an important role in control of the morphology. Since π-shaped ABC block copolymers can be reduced to linear ABC and star ABC block copolymers, they are good model copolymers for studying the self-assembly of complex block copolymers into micelles. The knowledge obtained in this work as well as the new morphologies identified provide useful information for future rational design and synthesis of novel multicompartment micelles.

  9. Enzymatically triggered multifunctional delivery system based on hyaluronic acid micelles

    KAUST Repository

    Deng, Lin

    2012-01-01

    Tumor targetability and stimuli responsivity of drug delivery systems (DDS) are key factors in cancer therapy. Implementation of multifunctional DDS can afford targetability and responsivity at the same time. Herein, cholesterol molecules (Ch) were coupled to hyaluronic acid (HA) backbones to afford amphiphilic conjugates that can self-assemble into stable micelles. Doxorubicin (DOX), an anticancer drug, and superparamagnetic iron oxide (SPIO) nanoparticles (NPs), magnetic resonance imaging (MRI) contrast agents, were encapsulated by Ch-HA micelles and were selectively released in the presence of hyaluronidase (Hyals) enzyme. Cytotoxicity and cell uptake studies were done using three cancer cell lines (HeLa, HepG2 and MCF7) and one normal cell line (WI38). Higher Ch-HA micelles uptake was seen in cancer cells versus normal cells. Consequently, DOX release was elevated in cancer cells causing higher cytotoxicity and enhanced cell death. © 2012 The Royal Society of Chemistry.

  10. Ionic quenching of naphthalene fluorescence in sodium dodecyl sulfate micelles.

    Science.gov (United States)

    Silva, Alessandra F; Fiedler, Haidi D; Nome, Faruk

    2011-03-31

    Micellar effects on luminescense of organic compounds or probes are well established, and here we show that quenching is highly favored in aqueous sodium dodecyl sulfate (SDS) micelles, which concentrate a naphthalene probe and cations of lanthanides, transition metals, and noble metals. Interactions have been studied by steady state and time-resolved fluorescence in examining the fluorescence suppression of naphthalene by metal ions in anionic SDS micelles. The quenching is collisional and correlated with the unit charge and the reduction potential of the metal ion. The rate constants, calculated in terms of local metal ion concentrations, are close to the diffusion control limit in the interior of SDS micelles, where the microscopic viscosity decreases the transfer rate, following the Stokes-Einstein relation.

  11. From micelle supramolecular assemblies in selective solvents to isoporous membranes.

    Science.gov (United States)

    Nunes, Suzana P; Karunakaran, Madhavan; Pradeep, Neelakanda; Behzad, Ali Reza; Hooghan, Bobby; Sougrat, Rachid; He, Haoze; Peinemann, Klaus-Viktor

    2011-08-16

    The supramolecular assembly of PS-b-P4VP copolymer micelles induced by selective solvent mixtures was used to manufacture isoporous membranes. Micelle order in solution was confirmed by cryo-scanning electron microscopy in casting solutions, leading to ordered pore morphology. When dioxane, a solvent that interacts poorly with the micelle corona, was added to the solution, polymer-polymer segment contact was preferential, increasing the intermicelle contact. Immersion in water gave rise to asymmetric porous membranes with exceptional pore uniformity and high porosity. The introduction of a small number of carbon nanotubes to the casting solution improved the membrane stability and the reversibility of the gate response in the presence of different pH values.

  12. From micelle supramolecular assemblies in selective solvents to isoporous membranes

    KAUST Repository

    Nunes, Suzana Pereira

    2011-08-16

    The supramolecular assembly of PS-b-P4VP copolymer micelles induced by selective solvent mixtures was used to manufacture isoporous membranes. Micelle order in solution was confirmed by cryo-scanning electron microscopy in casting solutions, leading to ordered pore morphology. When dioxane, a solvent that interacts poorly with the micelle corona, was added to the solution, polymer-polymer segment contact was preferential, increasing the intermicelle contact. Immersion in water gave rise to asymmetric porous membranes with exceptional pore uniformity and high porosity. The introduction of a small number of carbon nanotubes to the casting solution improved the membrane stability and the reversibility of the gate response in the presence of different pH values. © 2011 American Chemical Society.

  13. Casein micelles: size distribution in milks from individual cows.

    Science.gov (United States)

    de Kruif, C G Kees; Huppertz, Thom

    2012-05-09

    The size distribution and protein composition of casein micelles in the milk of Holstein-Friesian cows was determined as a function of stage and number of lactations. Protein composition did not vary significantly between the milks of different cows or as a function of lactation stage. Differences in the size and polydispersity of the casein micelles were observed between the milks of different cows, but not as a function of stage of milking or stage of lactation and not even over successive lactations periods. Modal radii varied from 55 to 70 nm, whereas hydrodynamic radii at a scattering angle of 73° (Q² = 350 μm⁻²) varied from 77 to 115 nm and polydispersity varied from 0.27 to 0.41, in a log-normal distribution. Casein micelle size in the milks of individual cows was not correlated with age, milk production, or lactation stage of the cows or fat or protein content of the milk.

  14. Anomalous diffusion and stress relaxation in surfactant micelles

    Science.gov (United States)

    Dhakal, Subas; Sureshkumar, Radhakrishna

    2017-07-01

    We investigate the mechanisms of anomalous diffusion in cationic surfactant micelles using molecular dynamics simulations in the presence of explicit salt and solvent-mediated interactions. Simulations show that when the counterion density increases, saddle-shaped branched interfaces manifest. In experiments, branched structures exhibit lower viscosity as compared to linear and wormlike micelles. This has long been attributed to stress relaxation arising from the sliding motion of branches along the main chain. Our simulations reveal a mechanism of branch motion resulting from an enhanced counterion condensation at the branched interfaces and provide quantitative evidence of stress relaxation facilitated by branched sliding. Furthermore, depending on the surfactant and salt concentrations, which in turn determine the microstructure, we observe normal, subdiffusive, and superdiffusive motions of surfactants. Specifically, superdiffusive behavior is associated with branch sliding, breakage and recombination of micelle fragments, as well as constraint release in entangled systems.

  15. Fabricating customized hydrogel contact lens

    Science.gov (United States)

    Childs, Andre; Li, Hao; Lewittes, Daniella M.; Dong, Biqin; Liu, Wenzhong; Shu, Xiao; Sun, Cheng; Zhang, Hao F.

    2016-10-01

    Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies.

  16. COMPARISON OF DRUG DELIVERY PROPERTIES OF PEG-b-PDHPC MICELLES WITH DIFFERENT COMPOSITIONS

    Institute of Scientific and Technical Information of China (English)

    Chun-yan Long; Ming-ming Sheng; Bin He; Yao Wu; Gang Wang; Zhong-wei Gu

    2012-01-01

    An anti-tumor drug doxombicin was encapsulated in micelles of poly(ethylene glycol)-b-poly(2,2-dihydroxyl-methyl propylene carbonate) (PEG-b-PDHPC) diblock copolymers.The morphology of both blank micelles and drug loaded micelles was characterized by TEM.The in vitro drug release profiles of micelles were investigated.The cytotoxicity of the micelles was evaluated by incubating with Hela tumor cells and 3T3 fibroblasts.The drug loaded micelles were co-cultured with HepG2 cells to evaluate the in vitro anti-tumor efficacies.The results showed that the mean sizes of both micelles with different copolymer compositions increased after being loaded with drugs.The drug release rate of PEG45-b-PDHPC34 micelles was faster than that of rnPEG114-b-PDHPC26 micelles.Both of the two block copolymers were non-toxic.The confocal laser scanning microscopy and flow cytometry results showed that both the drug loaded micelles could be internalized efficiently in HepG2 cells.The PEG45-b-PDHPC34 micelles exhibited higher anti-tumor activity comparing to mPEG114-b-PDHPC26 micelles.

  17. Controlled mixing of lanthanide(III) ions in coacervate core micelles.

    Science.gov (United States)

    Wang, Junyou; Velders, Aldrik H; Gianolio, Eliana; Aime, Silvio; Vergeldt, Frank J; Van As, Henk; Yan, Yun; Drechsler, Markus; de Keizer, Arie; Cohen Stuart, Martien A; van der Gucht, Jasper

    2013-05-01

    This article presents a facile strategy to combine Eu(3+) and Gd(3+) ions into coacervate core micelles in a controlled way with a statistical distribution of the ions. Consequently, the formed micelles show a high tunability between luminescence and relaxivity. These highly stable micelles present great potential for new materials, e.g. as bimodal imaging probes.

  18. Shell and core cross-linked poly(L-lysine)/poly(acrylic acid) complex micelles.

    Science.gov (United States)

    Hsieh, Yi-Hsuan; Hsiao, Yung-Tse; Jan, Jeng-Shiung

    2014-12-21

    We report the versatility of polyion complex (PIC) micelles for the preparation of shell and core cross-linked (SCL and CCL) micelles with their surface properties determined by the constituent polymer composition and cross-linking agent. The negatively and positively charged PIC micelles with their molecular structure and properties depending on the mixing weight percentage and polymer molecular weight were first prepared by mixing the negatively and positively charged polyions, poly(acrylic acid) (PAA) and poly(L-lysine) (PLL). The feasibility of preparing SCL micelles was demonstrated by cross-linking the shell of the negatively and positively charged micelles using cystamine and genipin, respectively. The core of the micelles can be cross-linked by silica deposition to stabilize the assemblies. The shell and/or core cross-linked micelles exhibited excellent colloid stability upon changing solution pH. The drug release from the drug-loaded SCL micelles revealed that the controllable permeability of the SCL micelles can be achieved by tuning the cross-linking degree and the SCL micelles exhibited noticeable pH-responsive behavior with accelerated release under acidic conditions. With the versatility of cross-linking strategies, it is possible to prepare a variety of SCL and CCL micelles from PIC micelles.

  19. Processing silk hydrogel and its applications in biomedical materials.

    Science.gov (United States)

    Wang, Hai-Yan; Zhang, Yu-Qing

    2015-01-01

    This review mainly introduces the types of silk hydrogels, their processing methods, and applications. There are various methods for hydrogel preparation, and many new processes are being developed for various applications. Silk hydrogels can be used in cartilage tissue engineering, drug release materials, 3D scaffolds for cells, and artificial skin, among other applications because of their porous structure and high porosity and the large surface area for growth, migration, adhesion and proliferation of cells that the hydrogels provide. All of these advantages have made silk hydrogels increasingly attractive. In addition, silk hydrogels have wide prospects for application in the field of biomedical materials.

  20. A comparative study of thermo-sensitive hydrogels with water-insoluble paclitaxel in molecule, nanocrystal and microcrystal dispersions.

    Science.gov (United States)

    Lin, Zhiqiang; Mei, Dong; Chen, Meiwan; Wang, Yitao; Chen, Xianhui; Wang, Zhaoyang; He, Bing; Zhang, Hua; Wang, Xueqing; Dai, Wenbing; Yin, Yuxin; Zhang, Qiang

    2015-09-28

    In situ thermo-sensitive hydrogels have attracted increasing attention for alternative cancer therapies due to their long-term and effective drug levels at local sites. Besides synthesizing new thermo-sensitive polymers, we can also fabricate this delivery system by combining a hydrogel with a thermo-response and drug in a different dispersion state, such as drug nanocrystals. However, the impact of the drug dispersion state or dimension on the quality of such a local injectable system is still unknown. So, here we developed and compared three types of F127 hydrogel systems with either paclitaxel or the near infra-red probe DiR in molecules (MOs), nanocrystals (NCs) and microcrystals (MCs), respectively. With 120 nm rod-shape nanocrystals, the NCs-Gel achieved a high drug loading, moderate drug release rate and gel erosion in vitro and in vivo, medium intratumoral drug residue but the best anti-tumor efficacy in 4T1 tumor bearing BALB/c mice. With the free drug solubilized in 20 nm micelles of the gel, the MOs-Gel system demonstrated the least drug loading and the fastest drug release and gel erosion, leading to the least intratumoral residue as well as the lowest anti-tumor effect. Finally, when dispersed in micron-grade rod-shape drug crystals, the MCs-Gel exhibited a high drug loading but poor stability, precipitating in vitro and in vivo, the highest intratumoral residue but the least drug release, resulting in moderate tumor inhibition. In conclusion, this study clarifies the effect of the drug dispersion state and scale on the behavior of a thermo-sensitive hydrogel, indicating the advantage of the NCs-Gel system, and it provides a basis for the future design of the local delivery of hydrophobic anti-cancer agents.

  1. A comparative study of thermo-sensitive hydrogels with water-insoluble paclitaxel in molecule, nanocrystal and microcrystal dispersions

    Science.gov (United States)

    Lin, Zhiqiang; Mei, Dong; Chen, Meiwan; Wang, Yitao; Chen, Xianhui; Wang, Zhaoyang; He, Bing; Zhang, Hua; Wang, Xueqing; Dai, Wenbing; Yin, Yuxin; Zhang, Qiang

    2015-09-01

    In situ thermo-sensitive hydrogels have attracted increasing attention for alternative cancer therapies due to their long-term and effective drug levels at local sites. Besides synthesizing new thermo-sensitive polymers, we can also fabricate this delivery system by combining a hydrogel with a thermo-response and drug in a different dispersion state, such as drug nanocrystals. However, the impact of the drug dispersion state or dimension on the quality of such a local injectable system is still unknown. So, here we developed and compared three types of F127 hydrogel systems with either paclitaxel or the near infra-red probe DiR in molecules (MOs), nanocrystals (NCs) and microcrystals (MCs), respectively. With 120 nm rod-shape nanocrystals, the NCs-Gel achieved a high drug loading, moderate drug release rate and gel erosion in vitro and in vivo, medium intratumoral drug residue but the best anti-tumor efficacy in 4T1 tumor bearing BALB/c mice. With the free drug solubilized in 20 nm micelles of the gel, the MOs-Gel system demonstrated the least drug loading and the fastest drug release and gel erosion, leading to the least intratumoral residue as well as the lowest anti-tumor effect. Finally, when dispersed in micron-grade rod-shape drug crystals, the MCs-Gel exhibited a high drug loading but poor stability, precipitating in vitro and in vivo, the highest intratumoral residue but the least drug release, resulting in moderate tumor inhibition. In conclusion, this study clarifies the effect of the drug dispersion state and scale on the behavior of a thermo-sensitive hydrogel, indicating the advantage of the NCs-Gel system, and it provides a basis for the future design of the local delivery of hydrophobic anti-cancer agents.

  2. Synthesis of mesoporous TiO2/SiO2 hybrid films as an efficient photocatalyst by polymeric micelle assembly.

    Science.gov (United States)

    Li, Yunqi; Bastakoti, Bishnu Prasad; Imura, Masataka; Hwang, Soo Min; Sun, Ziqi; Kim, Jung Ho; Dou, Shi Xue; Yamauchi, Yusuke

    2014-05-12

    Thermally stable mesoporous TiO2/SiO2 hybrid films with pore size of 50 nm have been synthesized by adopting the polymeric micelle-assembly method. A triblock copolymer, poly(styrene-b-2-vinyl pyridine-b-ethylene oxide), which serves as a template for the mesopores, was utilized to form polymeric micelles. The effective interaction of titanium tetraisopropoxide (TTIP) and tetraethyl orthosilicate (TEOS) with the polymeric micelles enabled us to fabricate stable mesoporous films. By changing the molar ratio of TEOS and TTIP, several mesoporous TiO2/SiO2 hybrid films with different compositions can be synthesized. The presence of amorphous SiO2 phase effectively retards the growth of anatase TiO2 crystal in the pore walls and retains the original mesoporous structure, even at higher temperature (650 °C). These TiO2/SiO2 hybrid films are of very high quality, without any cracks or voids. The addition of SiO2 phase to mesoporous TiO2 films not only adsorbs more organic dyes, but also significantly enhances the photocatalytic activity compared to mesoporous pure TiO2 film without SiO2 phase. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Curcumin and Osteosarcoma: Can Invertible Polymeric Micelles Help?

    Directory of Open Access Journals (Sweden)

    Avudaiappan Maran

    2016-06-01

    Full Text Available Systematic review of experimental and clinical data on the use of curcumin in the treatment of osteosarcoma is presented. The current status of curcumin’s therapeutic potential against bone cancer is analyzed in regard to using polymeric micelles (including recently developed invertible, responsive, micelles as a platform for curcumin delivery to treat osteosarcoma. The potential of micellar assemblies from responsive macromolecules in a controlled delivery of curcumin to osteosarcoma cells, and the release using a new inversion mechanism is revealed.

  4. Folding of DsbB in mixed micelles

    DEFF Research Database (Denmark)

    Otzen, Daniel

    2003-01-01

    is sensitive to changes in lipid and detergent composition. As an attempt to overcome this problem, I present a kinetic analysis of the folding of a membrane protein, disulfide bond reducing protein B (DsbB), in a mixed micelle system consisting of varying molar ratios of sodium dodecyl sulfate (SDS...... data are always open to alternative interpretations, time-resolved studies in mixed micelles provide a useful approach to measure membrane protein stability over a wide range of concentrations of SDS and DM, as well as a framework for the future characterization of the DsbB folding mechanism....

  5. Temperature responsive hydrogel nanofibers and nanoparticles

    Science.gov (United States)

    Ruokolainen, Janne

    2011-03-01

    Poly(N-isopropylacrylamide) (PNIPAM) is one of the most extensively investigated synthetic temperature-responsive polymers. In this work temperature-responsive PNIPAM based triblock copolymer hydrogels, their self-assembly and phase behavior in bulk, are described. Additionally, recent results from responsive hydrogel nanofibers and hydrogel nanoparticles are shown. It is known that block copolymers form well-organized nano structures in bulk or thin films when annealed thermally or in solvent vapours. However, in the case of nanofibers or nanoparticles, the annealing leads in most cases to aggregation and particle sintering. This work utilizes aerosol-based gas phase method where the preparation and annealing of hydrogel nanoparticles with well-organized, hierarchical inner structures are performed without any particle coagulation or sintering. In the method, the block copolymers assemble within aerosol nanoparticles to form, for instance, lamellar onion-like or gyroid inner structures.

  6. Responsive polyelectrolyte hydrogels and soft matter micromanipulation

    NARCIS (Netherlands)

    Glazer, P.J.

    2013-01-01

    This dissertation describes experimental studies on the mechanisms underlying the dynamic response of polyelectrolyte hydrogels when submitted to an external electric potential. In addition, we explore the possibilities of miniaturization and manipulation of responsive gels and other soft matter sys

  7. Hydrogels made from chitosan and silver nitrate.

    Science.gov (United States)

    Kozicki, Marek; Kołodziejczyk, Marek; Szynkowska, Małgorzata; Pawlaczyk, Aleksandra; Leśniewska, Ewa; Matusiak, Aleksandra; Adamus, Agnieszka; Karolczak, Aleksandra

    2016-04-20

    This work describes a gelation of chitosan solution with silver nitrate. Above the critical concentration of chitosan (c*), continuous hydrogels of chitosan-silver can be formed. At lower concentrations, the formation of nano- and micro-hydrogels is discussed. The sol-gel analysis was performed to characterise the hydrogels' swelling properties. Moreover, the following were employed: (i) mechanical testing of hydrogels, (ii) inductively coupled plasma-optical emission spectroscopy (ICP-OES) for the measurement of silver concentration, (iii) scanning electron microscopy (SEM) to examine the morphology of products obtained, and (iv) dynamic light scattering (DLS) and UV-vis spectrophotometry to examine products formed at low concentration of chitosan (chydrogels were used for modification of cotton fabric in order to give it antimicrobial properties. The products obtained acted against Escherichia coli and Bacillus subtilis apart from the chitosan used that showed no such activity.

  8. Diketopyrrolopyrrole Amphiphile-Based Micelle-Like Fluorescent Nanoparticles for Selective and Sensitive Detection of Mercury(II) Ions in Water.

    Science.gov (United States)

    Nie, Kaixuan; Dong, Bo; Shi, Huanhuan; Liu, Zhengchun; Liang, Bo

    2017-03-07

    A technique for encapsulating fluorescent organic probes in a micelle system offers an important alternative method to manufacture water-soluble organic nanoparticles (ONPs) for use in sensing Hg(2+). This article reports on a study of a surfactant-free micelle-like ONPs based on a 3,6-di(2-thienyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (TDPP) amphiphile, (2-(2-(2-methoxyethoxy)ethyl)-3,6-di(2-thiophyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (NDPP) fabricated to monitor Hg(2+) in water. NDPP was synthesized through a simple one-step modification of a commercially available dye TDPP with a flexible and hydrophilic alkoxy. This study reports, for the first time, that TDPP dyes can respond reversibly, sensitively, and selectively to Hg(2+) through TDPP-Hg-TDPP complexation, similar to the well-known thymine(T)-Hg-thymine(T) model and the accompanying molecular aggregation. Interestingly, transmission electron microscopy (TEM) and dynamic light scattering (DLS) confirmed that, in water, NDPP forms loose micelle-like fluorescent ONPs with a hydrohobic TDPP portion encapsulated inside. These micelle-like nanoparticles offer an ideal location for TDPP-Hg complexation with a modest molecular aggregation, thereby providing both clear visual and spectroscopic signals for Hg(2+) sensing. An estimated detection limit of 11 nM for Hg(2+) sensing with this NDPP nanoparticle was obtained. In addition, NDPP ONPs show good water solubility and high selectivity to Hg(2+) in neutral or alkalescent water. It was superior to most micelle-based nanosensors, which require a complicated process in the selection or synthesis of suitable surfactants. The determinations in real samples (river water) were made and satisfactory results were achieved. This study provides a low-cost strategy for fabricating small molecule-based fluorescent nanomaterials for use in sensing Hg(2+). Moreover, the NDPP nanoparticles show potential ability in Hg(2+) ion adsorption and recognization of

  9. Further development of a morphine hydrogel suppository.

    OpenAIRE

    Cole, L.; Hanning, C. D.; Robertson, S.; Quinn, K

    1990-01-01

    1. A sustained release monolithic morphine hydrogel suppository (MHS) was developed and administered to five volunteers. 2. The MHS delivered a mean of 55 mg morphine over 12 h. The mean plasma morphine concentration was 15 ng ml-1 from 2 to 12 h after administration. 3. Plasma morphine concentrations were comparable with those reported for the same dose given orally over the same time period. 4. The morphine hydrogel suppository appears to be an effective means of delivering morphine and may...

  10. Multitriggered Shape-Memory Acrylamide-DNA Hydrogels.

    Science.gov (United States)

    Lu, Chun-Hua; Guo, Weiwei; Hu, Yuwei; Qi, Xiu-Juan; Willner, Itamar

    2015-12-23

    Acrylamide-acrylamide nucleic acids are cross-linked by two cooperative functional motives to form shaped acrylamide-DNA hydrogels. One of the cross-linking motives responds to an external trigger, leading to the dissociation of one of the stimuli-responsive bridges, and to the transition of the stiff shaped hydrogels into soft shapeless states, where the residual bridging units, due to the chains entanglement, provide an intrinsic memory for the reshaping of the hydrogels. Subjecting the shapeless states to counter stimuli restores the dissociated bridges, and regenerates the original shape of the hydrogels. By the cyclic dissociation and reassembly of the stimuli-responsive bridges, the reversible switchable transitions of the hydrogels between stiff shaped hydrogel structures and soft shapeless states are demonstrated. Shaped hydrogels bridged by K(+)-stabilized G-quadruplexes/duplex units, by i-motif/duplex units, or by two different duplex bridges are described. The cyclic transitions of the hydrogels between shaped and shapeless states are stimulated, in the presence of appropriate triggers and counter triggers (K(+) ion/crown ether; pH = 5.0/8.0; fuel/antifuel strands). The shape-memory hydrogels are integrated into shaped two-hydrogel or three-hydrogel hybrid structures. The cyclic programmed transitions of selective domains of the hybrid structures between shaped hydrogel and shapeless states are demonstrated. The possible applications of the shape-memory hydrogels for sensing, inscription of information, and controlled release of loads are discussed.

  11. Binding of chloroquine to ionic micelles: Effect of pH and micellar surface charge

    Energy Technology Data Exchange (ETDEWEB)

    Souza Santos, Marcela de, E-mail: marcelafarmausp77@gmail.com [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Perpétua Freire de Morais Del Lama, Maria, E-mail: mpemdel@fcfrp.usp.br [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Departamento de Química Analítica, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, s/n, Campinas, São Paulo 13083-970 (Brazil); Siuiti Ito, Amando, E-mail: amandosi@ffclrp.usp.br [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14040-901 (Brazil); and others

    2014-03-15

    The pharmacological action of chloroquine relies on its ability to cross biological membranes in order to accumulate inside lysosomes. The present work aimed at understanding the basis for the interaction between different chloroquine species and ionic micelles of opposite charges, the latter used as a simple membrane model. The sensitivity of absorbance and fluorescence of chloroquine to changes in its local environment was used to probe its interaction with cetyltrimethylammonium micelles presenting bromide (CTAB) and sulfate (CTAS) as counterions, in addition to dodecyl sulfate micelles bearing sodium (SDS) and tetramethylammonium (TMADS) counterions. Counterion exchange was shown to have little effect on drug–micelle interaction. Chloroquine first dissociation constant (pKa{sub 1}) shifted to opposite directions when anionic and cationic micelles were compared. Chloroquine binding constants (K{sub b}) revealed that electrostatic forces mediate charged drug–micelle association, whereas hydrophobic interactions allowed neutral chloroquine to associate with anionic and cationic micelles. Fluorescence quenching studies indicated that monoprotonated chloroquine is inserted deeper into the micelle surface of anionic micelles than its neutral form, the latter being less exposed to the aqueous phase when associated with cationic over anionic assemblies. The findings provide further evidence that chloroquine–micelle interaction is driven by a tight interplay between the drug form and the micellar surface charge, which can have a major effect on the drug biological activity. -- Highlights: • Chloroquine (CQ) pKa{sub 1} increased for SDS micelles and decreased for CTAB micelles. • CQ is solubilized to the surface of both CTAB and SDS micelles. • Monoprotonated CQ is buried deeper into SDS micelles than neutral CQ. • Neutral CQ is less exposed to aqueous phase in CTAB over SDS micelles. • Local pH and micellar surface charge mediate interaction of CQ with

  12. Hydrogel: Preparation, characterization, and applications: A review

    Directory of Open Access Journals (Sweden)

    Enas M. Ahmed

    2015-03-01

    Full Text Available Hydrogel products constitute a group of polymeric materials, the hydrophilic structure of which renders them capable of holding large amounts of water in their three-dimensional networks. Extensive employment of these products in a number of industrial and environmental areas of application is considered to be of prime importance. As expected, natural hydrogels were gradually replaced by synthetic types due to their higher water absorption capacity, long service life, and wide varieties of raw chemical resources. Literature on this subject was found to be expanding, especially in the scientific areas of research. However, a number of publications and technical reports dealing with hydrogel products from the engineering points of view were examined to overview technological aspects covering this growing multidisciplinary field of research. The primary objective of this article is to review the literature concerning classification of hydrogels on different bases, physical and chemical characteristics of these products, and technical feasibility of their utilization. It also involved technologies adopted for hydrogel production together with process design implications, block diagrams, and optimized conditions of the preparation process. An innovated category of recent generations of hydrogel materials was also presented in some details.

  13. Static structure factor of polymerlike micelles: Overall dimension, flexibility, and local properties of lecithin reverse micelles in deuterated isooctane

    DEFF Research Database (Denmark)

    Jerke, G.; Pedersen, J.S.; Egelhaaf, S.U.

    1997-01-01

    We report a systematic investigation of the static structure factor S(q,c) of polymerlike reverse micelles formed by soybean lecithin and trace amounts of water in deuterated isooctane using small-angle neutron scattering and static light scattering. The experimental data for different concentrat......We report a systematic investigation of the static structure factor S(q,c) of polymerlike reverse micelles formed by soybean lecithin and trace amounts of water in deuterated isooctane using small-angle neutron scattering and static light scattering. The experimental data for different...

  14. Interactions between dyes and surfactants in inkjet ink used for textiles.

    Science.gov (United States)

    Park, Ju-Young; Hirata, Yuichi; Hamada, Kunihiro

    2011-01-01

    Optimal preparation of inkjet ink should be possible through the elucidation of the relationship between dye/additive interactions and ink performance. In the present study, the interactions between the dyes and surfactant additives were investigated. To investigate the physical properties of the surfactants used, the critical micelle concentration (cmc) and the aggregation number (N) were determined using electron spin resonance, static light-scattering, and fluorescence spectroscopy. On the basis of the cmc and N values, the visible absorption spectra of aqueous acid dye solutions (C. I. Acid Red 88, 13, and 27) containing surfactants (i.e., Surfynol 465 (S465), octaethylene glycol monododecyl ether (OGDE), and sodium dodecyl sulfate (SDS)) were measured. From the dependence of the spectra on the surfactant concentration, the binding constants, K(bind), of the acid dyes with the surfactant micelles were calculated: the K(bind) values decreased in the order of C. I. Acid Red 88 > C. I. Acid Red 13 > C. I. Acid Red 27, which correlates with the number of sulfonate groups. For all the dyes, the K(bind) values with the nonionic surfactants, S465 and OGDE, were much larger than those with the anionic surfactant, SDS. The thermodynamic parameters of the binding, i.e., the enthalpy change, ΔH(bind), and entropy change, ΔS(bind), were determined via the temperature dependence of the binding constants. The positive ΔH(bind) value for S465 indicates an endothermic binding process, while the negative ΔH(bind) values for SDS and OGDE indicate exothermic binding processes.

  15. Role of Synthetic and Dimensional Synthetic Organic Chemistry in Block Copolymer Micelle Nanosensor Engineering

    DEFF Research Database (Denmark)

    Ek, Pramod Kumar

    micelles. Shell cross-linking on PEG-b-PAEMA-b-PS micelles was performed by amidation reactions between the amino groups of PAEMA blocks using a di-carboxylic acid cross-linker. Also a dendritic cross-linker based click chemistry was used to stabilize the PEG-b-PAEMA-b-PES micelle having click readied PES...... micellisation of these functionalized unimers followed by dendritic click shell cross-linking resulted in a stable cRGDfK targeted mixed micelle pH nanosensor. Thus, the engineerability of triblock core-shell-corona micelle was utilized for the synthesis of ratiometric pH nanosensor having desired p...

  16. Croatian Traditional Herbal Dyes For Textile Dyeing

    OpenAIRE

    Sutrlović, Ana

    2011-01-01

    Textiles, namely protein fibers, in continental part of central Europe have been traditionally dyed by natural dyes. In the process textile materials were pre or after treated by metal salts – mordants (usually: KAl(SO4)2•12H2O, SnCl2•2H2O, FeSO4•7H2O, CuSO4•5H2O). Most represented active substances in herbal extracts are flavonoid derivatives, which by complexing with metal ions constitute colored complexes. Depending on herb species and mordant applied, a wide palette of colors is available...

  17. Laser dye technology

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, P R

    1999-09-01

    The author has worked with laser dyes for a number of years. A first interest was in the Navy blue-green program where a flashlamp pumped dye laser was used as an underwater communication and detection device. It made use of the optical window of sea-water--blue for deep ocean, green for coastal water. A major activity however has been with the Atomic Vapor Laser Isotope Separation Program (AVLIS) at the Lawrence Livermore National Laboratory. The aim here has been enriching isotopes for the nuclear fuel cycle. The tunability of the dye laser is utilized to selectively excite one isotope in uranium vapor, and this isotope is collected electrostatically as shown in Figure 1. The interests in the AVLIS program have been in the near ultra-violet, violet, red and deep-red.

  18. Hair cosmetics: dyes.

    Science.gov (United States)

    Guerra-Tapia, A; Gonzalez-Guerra, E

    2014-11-01

    Hair plays a significant role in body image, and its appearance can be changed relatively easily without resort to surgical procedures. Cosmetics and techniques have therefore been used to change hair appearance since time immemorial. The cosmetics industry has developed efficient products that can be used on healthy hair or act on concomitant diseases of the hair and scalp. Dyes embellish the hair by bleaching or coloring it briefly, for temporary periods of longer duration, or permanently, depending on the composition of a dye (oxidative or nonoxidative) and its degree of penetration of the hair shaft. The dermatologist's knowledge of dyes, their use, and their possible side effects (contact eczema, cancer, increased porosity, brittleness) can extend to an understanding of cosmetic resources that also treat hair and scalp conditions. Copyright © 2013 Elsevier España, S.L.U. and AEDV. All rights reserved.

  19. Hair Dye and Hair Relaxers

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women Hair Dye and Hair Relaxers Share Tweet Linkedin Pin it More sharing ... products. If you have a bad reaction to hair dyes and relaxers, you should: Stop using the ...

  20. Synthesis and characterization of novel carboxymethylcellulose hydrogels and carboxymethylcellulolse-hydrogel-ZnO-nanocomposites.

    Science.gov (United States)

    Hashem, M; Sharaf, S; Abd El-Hady, M M; Hebeish, A

    2013-06-05

    New approach for preparation of CMC hydrogels was undertaken through reacting CMC with either malic, succinic or citric acid. Characteristics of the hydrogels, as monitored by the swelling behavior, FTIR, SEM, EDX, TEM and XRD were dependent on nature and concentration of the polycarboxylic acid, time and temperature of curing. The best practice achieved from these studies was harnessed to synthesize and characterize CMC hydrogel-ZnO-nanocomposites with additional study pertaining to the antibacterial activity of the nanocomposites. CMC hydrogel with excellent swelling behavior could be prepared by adding succinic acid (0.5%) to CMC solution then drying the obtained paste at 80 °C for 5 min followed by curing at 120 °C for 3 min. Similarly, addition of ZnNO3 solution to the CMC paste results in CMC hydrogel-ZnO-nanocomposites having biocidal activity to gram +ve and gram -ve bacteria.

  1. A pH-sensitive Modified Polyacrylamide Hydrogel

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A pH-sensitive modified polyacrylamide hydrogel was prepared by two steps and the modified polyacrylamide was characterized by 1HNMR spectrum. The surface morphology and swelling behavior of the hydrogels were investigated.

  2. Dyes with high affinity for polylactide

    Institute of Scientific and Technical Information of China (English)

    Liang He; Shu Fen Zhang; Bing Tao Tang; Li Li Wang; Jin Zong Yang

    2007-01-01

    Attempts were made to develop dyes with high affinity for polylactide as an alternative to the existent commercial disperse dyes.The dyes synthesized according to the affinity concept of dye to polylactide exhibited excellent dyeing properties on polylactide compared with the commercial disperse dyes.

  3. Azaquinolone dye lasers

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, P.R.; Atkins, R.L.; Henry, R.A.; Fletcher, A.N.

    1978-07-25

    The invention provides a dye laser comprising a lasing solution of a 7-substituted azaquinolone-2 in which the aza nitrogen occupies at least one of the 5, 6 and 8 ring positions. The 7-substituent is hydroxy, alkoxy, amino or substituted amino. Substituents may be attached to other ring positions. The present lasing compounds are aza analogs of corresponding quinolone compounds and, hence, are named ''azaquinolone'' compounds. The dye lasers lase in the blue to near ultraviolet region.

  4. Hair care and dyeing.

    Science.gov (United States)

    Draelos, Zoe Diana

    2015-01-01

    Alopecia can be effectively camouflaged or worsened through the use of hair care techniques and dyeing. Proper hair care, involving hair styling and the use of mild shampoos and body-building conditioners, can amplify thinning scalp hair; however, chemical processing, including hair dyeing, permanent waving, and hair straightening, can encourage further hair loss through breakage. Many patients suffering from alopecia attempt to improve their hair through extensive manipulation, which only increases problems. Frequent haircuts to minimize split ends, accompanied by gentle handling of the fragile fibers, is best. This chapter offers the dermatologist insight into hair care recommendations for the alopecia patient.

  5. Dye solar cell research

    CSIR Research Space (South Africa)

    Cummings, F

    2009-11-01

    Full Text Available stream_source_info Cummings_2009.pdf.txt stream_content_type text/plain stream_size 3362 Content-Encoding UTF-8 stream_name Cummings_2009.pdf.txt Content-Type text/plain; charset=UTF-8 DYE SOLAR CELL RESEARCH Franscious... Cummings Energy and Processes Materials Science and Manufacturing Council for Scientific and Industrial Research P.O. Box 395 Pretoria 0001, South Africa 27 November 2009 CONTENT head2rightBackground head2rightCSIR Dye Solar Cell Research head2...

  6. Textile dye decolorization using cyanobacteria.

    Science.gov (United States)

    Parikh, Amit; Madamwar, Datta

    2005-03-01

    Cyanobacterial cultures isolated from sites polluted by industrial textile effluents were screened for their ability to decolorize cyclic azo dyes. Gloeocapsa pleurocapsoides and Phormidium ceylanicum decolorized Acid Red 97 and FF Sky Blue dyes by more than 80% after 26 days. Chroococcus minutus was the only culture which decolorized Amido Black 10B (55%). Chlorophyll a synthesis in all cultures was strongly inhibited by the dyes. Visible spectroscopy and TLC confirmed that color removal was due to degradation of the dyes.

  7. Biodegradable polymeric micelle-encapsulated doxorubicin suppresses tumor metastasis by killing circulating tumor cells

    Science.gov (United States)

    Deng, Senyi; Wu, Qinjie; Zhao, Yuwei; Zheng, Xin; Wu, Ni; Pang, Jing; Li, Xuejing; Bi, Cheng; Liu, Xinyu; Yang, Li; Liu, Lei; Su, Weijun; Wei, Yuquan; Gong, Changyang

    2015-03-01

    Circulating tumor cells (CTCs) play a crucial role in tumor metastasis, but it is rare for any chemotherapy regimen to focus on killing CTCs. Herein, we describe doxorubicin (Dox) micelles that showed anti-metastatic activity by killing CTCs. Dox micelles with a small particle size and high encapsulation efficiency were obtained using a pH-induced self-assembly method. Compared with free Dox, Dox micelles exhibited improved cytotoxicity, apoptosis induction, and cellular uptake. In addition, Dox micelles showed a sustained release behavior in vitro, and in a transgenic zebrafish model, Dox micelles exhibited a longer circulation time and lower extravasation from blood vessels into surrounding tissues. Anti-tumor and anti-metastatic activities of Dox micelles were investigated in transgenic zebrafish and mouse models. In transgenic zebrafish, Dox micelles inhibited tumor growth and prolonged the survival of tumor-bearing zebrafish. Furthermore, Dox micelles suppressed tumor metastasis by killing CTCs. In addition, improved anti-tumor and anti-metastatic activities were also confirmed in mouse tumor models, where immunofluorescent staining of tumors indicated that Dox micelles induced more apoptosis and showed fewer proliferation-positive cells. There were decreased side effects in transgenic zebrafish and mice after administration of Dox micelles. In conclusion, Dox micelles showed stronger anti-tumor and anti-metastatic activities and decreased side effects both in vitro and in vivo, which may have potential applications in cancer therapy.

  8. Polymeric micelles in anticancer therapy : Targeting, imaging and triggered release

    NARCIS (Netherlands)

    Oerlemans, Chris; Bult, Wouter; Bos, Mariska; Storm, Gert; Nijsen, J. Frank W.; Hennink, Wim E.

    2010-01-01

    Micelles are colloidal particles with a size around 5-100 nm which are currently under investigation as carriers for hydrophobic drugs in anticancer therapy. Currently, five micellar formulations for anticancer therapy are under clinical evaluation, of which Genexol-PM has been FDA approved for use

  9. Monitoring the aggregation of single casein micelles using fluorescence microscopy

    DEFF Research Database (Denmark)

    Bomholt, Julie; Moth-Poulsen, Kasper; Harboe, Marianne

    2011-01-01

    The aggregation of casein micelles (CMs) induced by milk-clotting enzymes is a process of fundamental importance in the dairy industry for cheese production; however, it is not well characterized on the nanoscale. Here we enabled the monitoring of the kinetics of aggregation between single CMs (30...

  10. Complex coacervate core micelles with a lysozyme-modified corona

    NARCIS (Netherlands)

    Danial, M.; Klok, H.A.; Norde, W.; Cohen Stuart, M.A.

    2007-01-01

    This paper describes the preparation, characterization, and enzymatic activity of complex coacervate core micelles (C3Ms) composed of poly(acrylic acid) (PAA) and poly(N-methyl-2-vinyl pyridinium iodide)-b-poly(ethylene oxide) (PQ2VP-PEO) to which the antibacterial enzyme lysozyme is end-attached.

  11. Dynamics of Chain Exchange in Block Copolymer Micelles

    Science.gov (United States)

    Lodge, Timothy

    Block copolymer micelles are rarely at equilibrium. The primary reason is the large number of repeat units in the insoluble block, Ncore, which makes the thermodynamic penalty for extracting a single chain (``unimer exchange'') substantial. As a consequence, the critical micelle concentration (CMC) is rarely accessed experimentally; however, in the proximity of a critical micelle temperature (CMT), equilibration is possible. We have been using time-resolved small angle neutron scattering (TR-SANS) to obtain a detailed picture of the mechanisms and time scales for chain exchange, at or near equilibrium. Our model system is poly(styrene)-block-poly(ethylene-alt-propylene)) (PS-PEP), in the PEP-selective solvent squalane (C30H62) . Equivalent micelles with either normal (hPS) or perdeuterated (dPS) cores are initially mixed in a blend of isotopically substituted squalane, designed to contrast-match a 50:50 hPS:dPS core. Samples are then annealed at a target temperature, and chain exchange is revealed quantitatively by the temporal decay in scattered intensity. The rate of exchange as function of concentration, temperature, Ncore, Ncorona, and chain architecture (diblock versus triblock) will be discussed.

  12. In vivo toxicity of cationic micelles and liposomes

    DEFF Research Database (Denmark)

    Knudsen, Kristina Bram; Northeved, Helle; Ek, Pramod Kumar

    2015-01-01

    This study investigated toxicity of nanocarriers comprised of cationic polymer and lipid components often used in gene and drug delivery, formulated as cationic micelles and liposomes. Rats were injected intravenously with 10, 25 or 100 mg/kg and sacrificed after 24 or 48 h, or 24 h after the last...

  13. Polymeric micelles in anticancer therapy : Targeting, imaging and triggered release

    NARCIS (Netherlands)

    Oerlemans, Chris; Bult, Wouter; Bos, Mariska; Storm, Gert; Nijsen, J. Frank W.; Hennink, Wim E.

    2010-01-01

    Micelles are colloidal particles with a size around 5-100 nm which are currently under investigation as carriers for hydrophobic drugs in anticancer therapy. Currently, five micellar formulations for anticancer therapy are under clinical evaluation, of which Genexol-PM has been FDA approved for use

  14. Structure and flexibility of worm-like micelles

    DEFF Research Database (Denmark)

    Jerke, G.; Pedersen, J.S.; Egelhaaf, S.U.

    1997-01-01

    Small-angle neutron scattering and static light scattering experiments have been performed on worm-like micelles formed by soybean lecithin and trace amounts of water in deuterated iso-octane. The structure and flexibility of the aggregates have been investigated as a function of solution...

  15. The Critical Micelle Concentration of Asphaltenes as Measured by Calorimetry

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Christensen, S. D.

    2000-01-01

    Micellization of asphaltenes in solution has been investigated using a micro calorimetric titration procedure (Andersen, S. I.; Birdi, K. S. J Colloid Interface Sci. 1991, 142, 497). The method uses the analysis of heat of dissociation and dilution of asphaltene micelles when a pure solvent (or s...

  16. Extraction of L-Aspartic Acid with Reverse Micelle System

    Directory of Open Access Journals (Sweden)

    Özlem AYDOĞAN

    2009-02-01

    Full Text Available The aim of this study is to investigate the extraction L-aspartic acid which is a hydrophobic amino acid with reverse micelle system. Production of amino acids by fermentation has been more important in recent years. These amino acids are obtained in dilute aqueous solutions and have to be separated from excess substrate, inorganic salts and by-products. Recently, separation of amino acids from fermentation media by reverse micelle extraction has received a great deal of attention. In this study, reverse micelle phase includes aliquat-336 as a surfactant, 1-decanol as a co-surfactant and isooctane as an apolar solvent. Experiments were performed at 150 rpm stirring rate, at 30 oC, for 30 min extraction time with equal volumes of reverse micelle and aqueous phases. Concentration of L-aspartic acid was analyzed by liquid chromatography (HPLC. The extraction yield increased with increasing pH and aliquat-336 concentration and with decreasing initial amino acid concentration. Maximum ekstraction yield (68 % was obtained at pH of 12, surfactant concentration of 200 mM and an initial amino acid concentration of 5 mM.

  17. Complex coacervation core micelles. Colloidal stability and aggregation mechanism

    NARCIS (Netherlands)

    Burgh, van der S.; Keizer, de A.; Cohen Stuart, M.A.

    2004-01-01

    Complex coacervation core micelles were prepared with various polyelectrolytes and oppositely charged diblock copolymers. The diblock copolymers consist of a charged block and a water-soluble neutral block. Our experimental technique was dynamic light scattering in combination with titrations. At

  18. Complex coacervate core micelles from iron-based coordination polymers.

    Science.gov (United States)

    Wang, Junyou; de Keizer, Arie; Fokkink, Remco; Yan, Yun; Cohen Stuart, Martien A; van der Gucht, Jasper

    2010-07-01

    Complex coacervate core micelles (C3Ms) from cationic poly(N-methyl-2-vinyl-pyridinium iodide)-b-poly(ethylene oxide) (P2MVP(41)-b-PEO(205)) and anionic iron coordination polymers are investigated in the present work. Micelle formation is studied by light scattering for both Fe(II)- and Fe(III)-containing C3Ms. At the stoichiometric charge ratio, both Fe(II)-C3Ms and Fe(III)-C3Ms are stable for at least 1 week at room temperature. Excess of iron coordination polymers has almost no effect on the formed Fe(II)-C3Ms and Fe(III)-C3Ms, whereas excess of P2MVP(41)-b-PEO(205) copolymers in the solution can dissociate the formed micelles. Upon increasing salt concentration, the scattering intensity decreases. This decrease is due to both a decrease in the number of micelles (or an increase in CMC) and a decrease in aggregation number. The salt dependence of the CMC and the aggregation number is explained using a scaling argument for C3M formation. Compared with Fe(II)-C3Ms, Fe(III)-C3Ms have a lower CMC and a higher stability against dissociation by added salt.

  19. Molecular dynamics simulation of a polysorbate 80 micelle in water

    NARCIS (Netherlands)

    Amani, Amir; York, Peter; de Waard, Hans; Anwar, Jamshed

    2011-01-01

    The structure and dynamics of a single molecule of the nonionic surfactant polysorbate 80 (POE (20) sorbitan monooleate; Tween 80 (R)) as well as a micelle comprising sixty molecules of polysorbate 80 in water have been investigated by molecular dynamics simulation. In its free state in water the po

  20. Casein Micelles: Size Distribution in Milks from Individual Cows

    NARCIS (Netherlands)

    de Kruif, C.G.; Huppertz, T.

    2012-01-01

    The size distribution and protein composition of casein micelles in the milk of Holstein-Friesian cows was determined as a function of stage and number of lactations. Protein composition did not vary significantly between the milks of different cows or as a function of lactation stage. Differences i

  1. Fluorescence dynamics of green fluorescent protein in AOT reversed micelles

    NARCIS (Netherlands)

    Uskova, M.A.; Borst, J.W.; Hink, M.A.; Hoek, van A.; Schots, A.; Klyachko, N.L.; Visser, A.J.W.G.

    2000-01-01

    We have used the enhanced green fluorescent protein (EGFP) to investigate the properties of surfactant-entrapped water pools in organic solvents (reversed micelles) with steady-state and time-resolved fluorescence methods. The surfactant used was sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and the

  2. Biochemical characterization of GM1 micelles-Amphotericin B interaction.

    Science.gov (United States)

    Leonhard, Victoria; Alasino, Roxana V; Bianco, Ismael D; Garro, Ariel G; Heredia, Valeria; Beltramo, Dante M

    2015-01-01

    In this work a thorough characterization of the GM1 micelle-Amphotericin B (AmB) interaction was performed. The micelle formation as well as the drug loading occurs spontaneously, although influenced by the physicochemical conditions, pH and temperature. The chromatographic profile of GM1-AmB complexes at different molar ratios shows the existence of two populations. The differential absorbance of GM1, monomeric and aggregate AmB, allowed us to discriminate the presence of all of them in both fractions. Thus, we noted that at higher proportion of AmB in the complex, increases the larger population which is composed mainly of aggregated AmB. The physical behavior of these micelles shows that both GM1- AmB complexes were stable in solution for at least 30 days. However upon freeze-thawing or lyophilization-solubilization cycles, only the smallest population, enriched in monomeric AmB, showed a complete solubilization. In vitro, GM1-AmB micelles were significantly less toxic on cultured cells than other commercial micellar formulations as Fungizone, but had a similar behavior to liposomal formulations as Ambisome. Regarding the antifungal activity of the new formulation, it was very similar to that of other formulations. The characterization of these GM1-AmB complexes is discussed as a potential new formulation able to improve the antifungal therapeutic efficiency of AmB.

  3. Poloxamer-based binary hydrogels for delivering tramadol hydrochloride: sol-gel transition studies, dissolution-release kinetics, in vitro toxicity, and pharmacological evaluation

    Directory of Open Access Journals (Sweden)

    dos Santos ACM

    2015-03-01

    Full Text Available Ana Claudia Mendonça dos Santos,1 Alessandra Cristina Santos Akkari,1 Iasmin Rosanne Silva Ferreira,2 Cintia Rodrigues Maruyama,3 Monica Pascoli,3 Viviane Aparecida Guilherme,4 Eneida de Paula,4 Leonardo Fernandes Fraceto,5 Renata de Lima,3 Patrícia da Silva Melo,2 Daniele Ribeiro de Araujo1 1Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Santo André, 2Faculdades Integradas Metropolitanas de Campinas, Campinas, 3Departamento de Biotecnologia, Universidade de Sorocaba, Sorocaba, 4Departamento de Bioquímica, Universidade Estadual de Campinas, Campinas, 5Departamento de Engenharia Ambiental, Universidade Estadual ‘Júlio de Mesquita Filho’, Sorocaba, São Paulo, Brazil Abstract: In this work, poloxamer (PL-based binary hydrogels, composed of PL 407 and PL 188, were studied with regard to the physicochemical aspects of sol-gel transition and pharmaceutical formulation issues such as dissolution-release profiles. In particular, we evaluated the cytotoxicity, genotoxicity, and in vivo pharmacological performance of PL 407 and PL 407–PL 188 hydrogels containing tramadol (TR to analyze its potential treatment of acute pain. Drug–micelle interaction studies showed the formation of PL 407–PL 188 binary systems and the drug partitioning into the micelles. Characterization of the sol-gel transition phase showed an increase on enthalpy variation values that were induced by the presence of TR hydrochloride within the PL 407 or PL 407–PL 188 systems. Hydrogel dissolution occurred rapidly, with approximately 30%–45% of the gel dissolved, reaching ~80%–90% up to 24 hours. For in vitro release assays, formulations followed the diffusion Higuchi model and lower Krel values were observed for PL 407 (20%, Krel =112.9±10.6 µg·h-1/2 and its binary systems PL 407–PL 188 (25%–5% and 25%–10%, Krel =80.8±6.1 and 103.4±8.3 µg·h-1/2, respectively in relation to TR solution (Krel =417.9±47.5 µg·h-1/2, P<0.001. In

  4. New in situ crosslinking chemistries for hydrogelation

    Science.gov (United States)

    Roberts, Meredith Colleen

    Over the last half century, hydrogels have found immense value as biomaterials in a vast number of biomedical and pharmaceutical applications. One subset of hydrogels receiving increased attention is in situ forming gels. Gelling by either bioresponsive self-assembly or mixing of binary crosslinking systems, these technologies are useful in minimally invasive applications as well as drug delivery systems in which the sol-to-gel transition aids the formulation's performance. Thus far, the field of in situ crosslinking hydrogels has received limited attention in the development of new crosslinking chemistries. Moreover, not only does the chemical nature of the crosslinking moieties allow these systems to perform in situ, but they contribute dramatically to the mechanical properties of the hydrogel networks. For example, reversible crosslinks with finite lifetimes generate dynamic viscoelastic gels with time-dependent properties, whereas irreversible crosslinks form highly elastic networks. The aim of this dissertation is to explore two new covalent chemistries for their ability to crosslink hydrogels in situ under physiological conditions. First, reversible phenylboronate-salicylhydroxamate crosslinking was implemented in a binary, multivalent polymeric system. These gels formed rapidly and generated hydrogel networks with frequency-dependent dynamic rheological properties. Analysis of the composition-structure-property relationships of these hydrogels---specifically considering the effects of pH, degree of polymer functionality, charge of the polymer backbone and polymer concentration on dynamic theological properties---was performed. These gels demonstrate diverse mechanical properties, due to adjustments in the binding equilibrium of the pH-sensitive crosslinks, and thus have the potential to perform in a range of dynamic or bioresponsive applications. Second, irreversible catalyst-free "click" chemistry was employed in the hydrogelation of multivalent azide

  5. Targeted therapy of colorectal neoplasia with rapamycin in peptide-labeled pegylated octadecyl lithocholate micelles.

    Science.gov (United States)

    Khondee, Supang; Rabinsky, Emily F; Owens, Scott R; Joshi, Bishnu P; Qiu, Zhen; Duan, Xiyu; Zhao, Lili; Wang, Thomas D

    2015-02-10

    Many powerful drugs have limited clinical utility because of poor water solubility and high systemic toxicity. Here, we formulated a targeted nanomedicine, rapamycin encapsulated in pegylated octadecyl lithocholate micelles labeled with a new ligand for colorectal neoplasia, LTTHYKL peptide. CPC;Apc mice that spontaneously develop colonic adenomas were treated with free rapamycin, plain rapamycin micelles, and peptide-labeled rapamycin micelles via intraperitoneal injection for 35days. Endoscopy was performed to monitor adenoma regression in vivo. We observed complete adenoma regression at the end of therapy. The mean regression rate for peptide-labeled rapamycin micelles was significantly greater than that for plain rapamycin micelles, Prapamycin micelles compared to that of free drug, and no other toxicities were found on chemistries. Together, this unique targeted micelle represents a potential therapeutic for colorectal neoplasia with comparable therapeutic efficacy to rapamycin free drug and significantly less systemic toxicity.

  6. Thermodynamics of micelle formation in a water-alcohol solution of sodium tetradecyl sulfate

    Science.gov (United States)

    Shilova, S. V.; Tret'yakova, A. Ya.; Barabanov, V. P.

    2016-01-01

    The effects of addition of ethanol and propan-1-ol on sodium tetradecyl sulfate micelle formation in an aqueous solution are studied via microprobe fluorescence microscopy and conductometry. The critical micelle concentration, quantitative characteristics of micelles, and thermodynamic parameters of micelle formation are determined. Addition of 5-15 vol % of ethanol or 5-10 vol % of propan-1-ol is shown to result in a lower critical micelle concentration than in the aqueous solution, and in the formation of mixed spherical micelles whose sizes and aggregation numbers are less than those for the systems without alcohol. The contribution from the enthalpy factor to the free energy of sodium tetradecyl sulfate micelle formation is found to dominate in mixed solvents, in contrast to aqueous solutions.

  7. Reverse micelles as suitable microreactor for increased biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Anjana [Nanotechnology and Molecular Biology Laboratory, Centre of Biotechnology, University of Allahabad, Allahabad 211002 (India); Pandey, Ashutosh [Centre of Energy Studies, MNNIT, Allahabad 211004 (India)

    2008-01-15

    Reverse micelles have been shown to act as efficient microreactors for enzymic reactions and whole cell entrapment in organic (non-aqueous) media wherein the reactants are protected from denaturation by the surrounding organic solvent. These micelles are thermodynamically stable, micrometer sized water droplets dispersed in an organic phase by a surfactant. It has been observed that when whole cells of photosynthetic bacteria (Rhodopseudomonas sphaeroides or Rhodobacter sphaeroides 2.4.1) are entrapped inside these reverse micelles, the H{sub 2} production enhanced from 25 to 35 folds. That is, 1.71mmol(mgprotein){sup -1}h{sup -1} in case of R. sphaeroides which is 25 fold higher in benzene-sodium lauryl sulfate reverse micelles. Whereas, in case of R. sphaeroides 2.4.1 the H{sub 2} production was increased by 35 fold within AOT-isooctane reverse micelles i.e. 11.5mmol(mgprotein){sup -1}h{sup -1}. The observations indicate that the entrapment of whole cells of microbes within reverse micelles provides a novel and efficient technique to produce hydrogen by the inexhaustible biological route. The two microorganisms R. sphaeroides 2.4.1 (a photosynthetic bacteria) and Citrobacter Y19 (a facultative anaerobic bacteria) together are also entrapped within AOT-isooctane and H{sub 2} production was measured i.e. 69mmol(mgprotein){sup -1}h{sup -1}. The nitrogenase enzyme responsible for hydrogen production by R. sphaeroides/R. sphaeroides 2.4.1 cells is oxygen sensitive, and very well protected within reverse micelles by the use of combined approach of two cells (R. sphaeroides 2.4.1 and Citrobacter Y19). In this case glucose present in the medium of Citrobacter Y19 serves double roles in enhancing the sustained production rate of hydrogen. Firstly, it quenches the free O{sub 2}liberated as a side product of reaction catalyzed by nitrogenase, which is O{sub 2} labile. Secondly, organic acid produced by this reaction is utilized by the Citrobacter Y19 as organic substrate in

  8. Preparation of bacterial cellulose based hydrogels and their viscoelastic behavior

    OpenAIRE

    2015-01-01

    Bacterial cellulose (BC) based hydrogels have been prepared in blended with carboxymethylcellulose and polyvinyl pyrrolidone by using heat treatment. The properties of BC-CMC and BC-PVP hydrogels were compared with pure BC, CMC and PVP hydrogels. These hydrogels were investigated by measuring their structural, morphological and viscoelastic properties. Through the morphological images, alignment of the porous flake like structures could be seen clearly within the inter-polymeric network of th...

  9. Gellan gum microgel-reinforced cell-laden gelatin hydrogels

    OpenAIRE

    Shin, Hyeongho; Olsen, Bradley D.; Khademhosseini, Ali

    2013-01-01

    The relatively weak mechanical properties of hydrogels remain a major drawback for their application as load-bearing tissue scaffolds. Previously, we developed cell-laden double-network (DN) hydrogels that were composed of photocrosslinkable gellan gum (GG) and gelatin. Further research into the materials as tissue scaffolds determined that the strength of the DN hydrogels decreased when they were prepared at cell-compatible conditions, and the encapsulated cells in the DN hydrogels did not f...

  10. Research on the printability of hydrogels in 3D bioprinting

    OpenAIRE

    Yong He; FeiFei Yang; HaiMing Zhao; Qing Gao; Bing Xia; JianZhong Fu

    2016-01-01

    As the biocompatible materials, hydrogels have been widely used in three- dimensional (3D) bioprinting/organ printing to load cell for tissue engineering. It is important to precisely control hydrogels deposition during printing the mimic organ structures. However, the printability of hydrogels about printing parameters is seldom addressed. In this paper, we systemically investigated the printability of hydrogels from printing lines (one dimensional, 1D structures) to printing lattices/films ...

  11. Experimental Study on Self-assembly of KLD-12 Peptide Hydrogel and 3-D Culture of MSC Encapsulated within Hydrogel In Vitro

    Institute of Scientific and Technical Information of China (English)

    Jianhua SUN; Qixin ZHENG

    2009-01-01

    o-fiber hydrogel in vitro. MSCs in KLD-12 peptide hydrogel grew well and proliferated with the culture time. KLD-12 peptide hydrogel can serve as an excellent injectable material of biological scaffolds in tissue engineering of IVD.

  12. A novel cellulose hydrogel prepared from its ionic liquid solution

    Institute of Scientific and Technical Information of China (English)

    LI Lu; LIN ZhangBi; YANG Xiao; WAN ZhenZhen; CUI ShuXun

    2009-01-01

    A novel cellulose hydrogel is prepared by regenerating cellulose from its ionic liquid solution. The transparency cellulose hydrogel presents a good chemical stability and an acceptable mechanical property. This non-toxic cellulose hydrogel should be biocompatibie and may be useful in the future as a biomaterial.

  13. Co-assembly of chitosan and phospholipids into hybrid hydrogels

    DEFF Research Database (Denmark)

    Mendes, Ana Carina Loureiro; Shekarforoush, Elhamalsadat; Engwer, Christoph

    2016-01-01

    Novel hybrid hydrogels were formed by adding chitosan (Ch) to phospholipids (P) self-assembled particles in lactic acid. The effect of the phospholipid concentration on the hydrogel properties was investigated and was observed to affect the rate of hydrogel formation and viscoelastic properties...

  14. Molecular dynamic simulations of the water absorbency of hydrogels.

    Science.gov (United States)

    Ou, Xiang; Han, Qiang; Dai, Hui-Hui; Wang, Jiong

    2015-09-01

    A polymer gel can imbibe solvent molecules through surface tension effect. When the solvent happens to be water, the gel can swell to a large extent and forms an aggregate called hydrogel. The large deformation caused by such swelling makes it difficult to study the behaviors of hydrogels. Currently, few molecular dynamic simulation works have been reported on the water absorbing mechanism of hydrogels. In this paper, we first use molecular dynamic simulation to study the water absorbing mechanism of hydrogels and propose a hydrogel-water interface model to study the water absorbency of the hydrogel surface. Also, the saturated water content and volume expansion rate of the hydrogel are investigated by building a hydrogel model with different cross-linking degree and by comparing the water absorption curves under different temperatures. The sample hydrogel model used consists of Polyethylene glycol diglycidyl ether (PEGDGE) as epoxy and the Jeffamine, poly-oxy-alkylene-amines, as curing agent. The conclusions obtained are useful for further investigation on PEGDGE/Jeffamine hydrogel. Moreover, the simulation methods, including hydrogel-water interface modeling, we first propose are also suitable to study the water absorbing mechanism of other hydrogels.

  15. A hydrogel-based enzyme-loaded polymersome reactor

    NARCIS (Netherlands)

    Hoog, de Hans-Peter; Arends, Isabel W.C.E.; Rowan, Alan E.; Cornelissen, Jeroen J.L.M.; Nolte, Roeland J.M.

    2010-01-01

    In this study we report the immobilization of enzyme-containing polymersomes into a macromolecular hydrogel. Whereas free enzyme shows progressive leakage from the hydrogel in a period of days, leakage of the polymersome-protected enzyme is virtually absent. The preparation of the hydrogel occurs un

  16. Hydrogels for an accommodating intraocular lens. An explorative study

    NARCIS (Netherlands)

    de Groot, JH; Spaans, CJ; van Calck, RV; van Beijma, FJ; Norrby, S; Pennings, AJ

    2003-01-01

    In this study it was investigated whether hydrogels could be used for an accommodating lens. The requirements of such a hydrogels are a low modulus, high refractive index, transparency, and strength. Since conventional hydrogels do not possess this combination of properties, a novel preparation meth

  17. A hydrogel-based enzyme-loaded polymersome reactor

    NARCIS (Netherlands)

    de Hoog, H.P.M.; de Hoog, Hans-Peter; Arends, Isabel W.C.E.; Rowan, Alan E.; Cornelissen, Jeroen Johannes Lambertus Maria; Nolte, Roeland J.M.

    2010-01-01

    In this study we report the immobilization of enzyme-containing polymersomes into a macromolecular hydrogel. Whereas free enzyme shows progressive leakage from the hydrogel in a period of days, leakage of the polymersome-protected enzyme is virtually absent. The preparation of the hydrogel occurs

  18. REUSE OF DECOLORIZED DYEING EFFLUENTS IN REPEATED DYEINGS

    Directory of Open Access Journals (Sweden)

    ÖNER Erhan

    2016-05-01

    Full Text Available In this experimental work, the effluents of the reactive and disperse dyeings were reused in the next dyeing after the decolourization by ozone gas. Accordingly, the polyester woven samples were dyed with C.I. Disperse Yellow 160, C.I. Disperse Red 77 and C.I. Disperse Blue 79:1, and the cotton woven samples were dyed with C.I. Reactive Yellow 176, C.I. Reactive Red 239 and C.I. Reactive Blue 221. The effluents of the dyeings with these dyes and also with their mixtures were decolorized by ozone gas. The colours of the samples dyed with the decolorized effluents were compared with the original dyeings (standards and the colour differences were calculated. Under the experimental conditions of this investigation, the many of the dyeing effluents were decolorized successfully, except the effluent of C.I. Disperse Red 77. In the case that this red disperse dye present in the dyebath, the decolorized effluent had a slight reddish colour. The colour differences between the original dyeing (standard and the samples dyed with the decolorized effluent are mostly below the tolerance (DE<1 or slightly above the tolerance. The solid colours and uniform dyeings were achieved in the dyeings. The method seems promising in decreasing the amount of water used in textile dyeings.

  19. OPTIMIZATION OF DYEING PARAMETERS TO DYE COTTON WITH CARROT EXTRACTION

    Directory of Open Access Journals (Sweden)

    MIRALLES Verónica

    2017-05-01

    Full Text Available Natural dyes derived from flora and fauna are believed to be safe because of non-toxic, non-carcinogenic and biodegradable nature. Furthermore, natural dyes do not cause pollution and waste water problems. Natural dyes as well as synthetic dyes need the optimum parameters to get a good dyeing. On some occasions, It is necessary the use of mordants to increase the affinity between cellulose fiber and natural dye, but there are other conditions to optimize in the dyeing process, like time, temperature, auxiliary porducts, etc. In addition, the optimum conditions are different depends on the type of dye and the fiber nature. The aim of this work is the use of carrot extract to dye cotton fabric by exhaustion at diverse dyeing conditions. Diffferent dyeing processes were carried out to study the effect of pH condition and the temperature, using 7, 6 and 4 pH values and 95 ºC and 130ºC for an hour. As a result some images of dyed samples are shown. Moreover, to evaluate the colour of each sample CIELAB parameters are analysed obtained by reflexion spectrophotometre. The results showed that the temperature used has an important influence on the colour of the dyed sample.

  20. Levitated droplet dye laser

    DEFF Research Database (Denmark)

    Azzouz, H.; Alkafadiji, L.; Balslev, Søren

    2006-01-01

    a high quality optical resonator. Our 750 nL lasing droplets consist of Rhodamine 6G dissolved in ethylene glycol, at a concentration of 0.02 M. The droplets are optically pumped at 532 nm light from a pulsed, frequency doubled Nd:YAG laser, and the dye laser emission is analyzed by a fixed grating...

  1. Microfluidic Dye Lasers

    DEFF Research Database (Denmark)

    Kristensen, Anders; Balslev, Søren; Gersborg-Hansen, Morten

    2006-01-01

    A technology for miniaturized, polymer based lasers, suitable for integration with planar waveguides and microfluidic networks is presented. The microfluidic dye laser device consists of a microfluidic channel with an embedded optical resonator. The devices are fabricated in a thin polymer film...

  2. Alzheimer's Dye Test?

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Massachusetts Institute of Technology (MIT) scientists have developed a new dye that could offer noninvasive early diagnosis of Alzheimer's disease, a discovery that could aid in monitoring the progression of the disease and in studying the efficacy of new treatments to stop it. The work is published in Angewandte Chemie. Today, doctors can only…

  3. Alzheimer's Dye Test?

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Massachusetts Institute of Technology (MIT) scientists have developed a new dye that could offer noninvasive early diagnosis of Alzheimer's disease, a discovery that could aid in monitoring the progression of the disease and in studying the efficacy of new treatments to stop it. The work is published in Angewandte Chemie. Today, doctors can only…

  4. Dye laser principles with applications

    CERN Document Server

    Duarte, Frank J; Liao, Peter F; Kelley, Paul

    1990-01-01

    A tutorial introduction to the field of dye lasers, Dye Laser Principles also serves as an up-to-date overview for those using dye lasers as research and industrial tools. A number of the issues discussed in this book are pertinent not only to dye lasers but also to lasers in general. Most of the chapters in the book contain problem sets that expand on the material covered in the chapter.Key Features* Dye lasers are among the most versatile and successful laser sources currently available in use Offering both pulsed and continuous-wave operation and tunable from the near ultraviole

  5. Synthesis of azo pyridone dyes

    OpenAIRE

    Mijin Dušan Ž.; Ušćumlić Gordana S.; Valentić Nataša V.; Marinković Aleksandar D.

    2011-01-01

    Over 50% of all colorants which are used nowdays are azo dyes and pigments, and among them arylazo pyridone dyes (and pigments) have became of interest in last several decades due to the high molar extinction coefficient, and the medium to high light and wet fastness properties. They find application generally as disperse dyes. The importance of disperse dyes increased in the 1970s and 1980s due to the use of polyester and nylon as the main synthetic fibers. Also, disperse dyes were use...

  6. TEXTILE DYEING AND FINISHING JOURNAL

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Abstract: Optim is dyed with Lanasol CE series dyes by micro-suspension technology, and the dyeing result is compared with that by traditional process. The optimal micro-suspension dyeing process is determined as follows: formic acid 1.5% (owl), micro-suspension promoter WR1.0% (owf), micro-suspension promoter TS 0.5 % (owl), dyestuff 5% (owf). The results show that micro-suspension dyeing increases the dye uptake percentage and colour fixation rate significantly; improves the handle and bulkiness without damaging the colour fastness of the dyed fabric.

  7. Hydrogel Actuation by Electric Field Driven Effects

    Science.gov (United States)

    Morales, Daniel Humphrey

    Hydrogels are networks of crosslinked, hydrophilic polymers capable of absorbing and releasing large amounts of water while maintaining their structural integrity. Polyelectrolyte hydrogels are a subset of hydrogels that contain ionizable moieties, which render the network sensitive to the pH and the ionic strength of the media and provide mobile counterions, which impart conductivity. These networks are part of a class of "smart" material systems that can sense and adjust their shape in response to the external environment. Hence, the ability to program and modulate hydrogel shape change has great potential for novel biomaterial and soft robotics applications. We utilized electric field driven effects to manipulate the interaction of ions within polyelectrolyte hydrogels in order to induce controlled deformation and patterning. Additionally, electric fields can be used to promote the interactions of separate gel networks, as modular components, and particle assemblies within gel networks to develop new types of soft composite systems. First, we present and analyze a walking gel actuator comprised of cationic and anionic gel legs attached by electric field-promoted polyion complexation. We characterize the electro-osmotic response of the hydrogels as a function of charge density and external salt concentration. The gel walkers achieve unidirectional motion on flat elastomer substrates and exemplify a simple way to move and manipulate soft matter devices in aqueous solutions. An 'ionoprinting' technique is presented with the capability to topographically structure and actuate hydrated gels in two and three dimensions by locally patterning ions induced by electric fields. The bound charges change the local mechanical properties of the gel to induce relief patterns and evoke localized stress, causing rapid folding in air. The ionically patterned hydrogels exhibit programmable temporal and spatial shape transitions which can be tuned by the duration and/or strength of

  8. Dye Aggregation in Ink Jet

    Institute of Scientific and Technical Information of China (English)

    Thomas Paul; Sarfraz Hussain

    2004-01-01

    Dye aggregation has long been recognised as a key factor in performance, and this is no less so in ink jet applications. The aggregation state was shown to be important in many different areas ranging from the use of dyes in photodynamic therapies all the way to colorants for dying of fabrics. Therefore different methods to investigate dye association qualitatively and quantitatively were developed. A simple procedure to study aggregation could be a useful tool to characterise dyes for ink jet printing. It is critically reviewed the methods used to study dye aggregation, and discussed some of the main conclusions. This will be illustrated by examples of ink jet dye aggregation and its study in aqueous and ink systems. The results are used to correlate the solution behaviour of dyes with their print performance.

  9. Optical Properties of Fluorescent Dyes

    Institute of Scientific and Technical Information of China (English)

    李戎; 陈东辉

    2001-01-01

    Fluorescent dyes have been widely used these years.Because of the special optical performance, conventional CCM systems seem to be unable to predict the recipes of fabrics dyed with fluorescent dyes. In order to enhance the functions of CCM systems, the optical properties of fluorescent dyes in their absorption region were investigated. It has been found that there was a fixed maximum absorption wavelength for each fluorescent dyes whatever its concentration is. Both absorption region and maximum absorption wavelength of the dyes in solution are the same to those in fabric, and that the absorption is directly proportional to the concentration of the dye. So the optical properties obtained in solutions cna be applied for describing the optics performance of fluorescent dyes in fabrics.

  10. Radiolabeling of liposomes and polymeric micelles with PET-isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ingemann Jensen, A.T.

    2013-06-01

    This thesis is divided into three separate chapters that can be read independently. Chapter 1 is a general introduction, touching upon liposomes and polymeric micelles and radiolabeling with 18F and 64Cu. Chapter 2 and 3 address two separate research projects, each described below. A complete reference list is compiled in the end, immediately after the three chapters. This is followed by the supplementary information, divided into appropriate sections. Finally, the two first-authored manuscripts are attached as appendices. Chapter 1. The field of nanoparticulate drug delivery has been hailed as a revolution in modern therapeutics, especially in chemotherapy. A major reason is the ability of nanoparticles to accumulate in tumor tissue. Liposomes are the classic nanoparticle, consisting of a lipid membrane with an aqueous core. Polymeric micelles are made from amphiphilic detergent-like copolymers, that self-assemble in water. Therapy with nanoparticles is hampered by often poor tumor accumulation, combined with massive uptake by macrophages in the liver and spleen. For this reason, visualizing nanoparticle pharmacokinetics in-vivo is a valuable tool in the on-going research. Such visualization can be done by labeling with radio isotopes. Isotopes that emit positrons (PET-isotopes) can be detected by PET (positron emission tomography) technology, an accurate technique that has gained popularity in recent years. PET-isotopes of interest include 18F and 64Cu. In addition to being a research tool, radiolabeled nanoparticles hold promise as a radiopharmaceutical in themselves, as a means of imaging tumor tissue, aiding in diagnosis and surgery. Chapter 2. A method for labeling liposomes with 18F (97% positron decay, T = 110 min) was investigated. 18F is widely available, but is hampered by a short half-life only allowing up to 8 hours scans. 18F must be covalently attached to components of the liposome. By binding to a lipid, it can be stably lodged in the membrane. A

  11. Magnetic hyaluronate hydrogels: preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Tóth, Ildikó Y., E-mail: Ildiko.Toth@chem.u-szeged.hu; Veress, Gábor; Szekeres, Márta; Illés, Erzsébet; Tombácz, Etelka, E-mail: tombacz@chem.u-szeged.hu

    2015-04-15

    A novel soft way of hyaluronate (HyA) based magnetic hydrogel preparation was revealed. Magnetite nanoparticles (MNPs) were prepared by co-precipitation. Since the naked MNPs cannot be dispersed homogenously in HyA-gel, their surface was modified with natural and biocompatible chondroitin-sulfate-A (CSA) to obtain CSA-coated MNPs (CSA@MNPs). The aggregation state of MNPs and that loaded with increasing amount of CSA up to 1 mmol/g was measured by dynamic light scattering at pH~6. Only CSA@MNP with ≥0.2 mmol/g CSA content was suitable for magnetic HyA-gel preparation. Rheological studies showed that the presence of CSA@MNP with up to 2 g/L did not affect the hydrogel's rheological behavior significantly. The results suggest that the HyA-based magnetic hydrogels may be promising formulations for future biomedical applications, e.g. as intra-articular injections in the treatment of osteoarthritis. - Highlights: • Novel hyaluronate(HyA)-based biocompatible magnetic hydrogels were prepared. • Chondroitin-sulfate-A coating is needed to disperse magnetite particles in HyA-gel. • Rheological behavior of hydrogels was independent of the magnetite content (<2 g/L). • Gels remained in stable and homogeneously dispersed state even after 90 days storage. • Magnetic HyA-gels are promising candidates for use as intra-articular injection.

  12. Calculations of critical micelle concentration by dissipative particle dynamics simulations: the role of chain rigidity.

    Science.gov (United States)

    Lee, Ming-Tsung; Vishnyakov, Aleksey; Neimark, Alexander V

    2013-09-05

    Micelle formation in surfactant solutions is a self-assembly process governed by complex interplay of solvent-mediated interactions between hydrophilic and hydrophobic groups, which are commonly called heads and tails. However, the head-tail repulsion is not the only factor affecting the micelle formation. For the first time, we present a systematic study of the effect of chain rigidity on critical micelle concentration and micelle size, which is performed with the dissipative particle dynamics simulation method. Rigidity of the coarse-grained surfactant molecule was controlled by the harmonic bonds set between the second-neighbor beads. Compared to flexible molecules with the nearest-neighbor bonds being the only type of bonded interactions, rigid molecules exhibited a lower critical micelle concentration and formed larger and better-defined micelles. By varying the strength of head-tail repulsion and the chain rigidity, we constructed two-dimensional diagrams presenting how the critical micelle concentration and aggregation number depend on these parameters. We found that the solutions of flexible and rigid molecules that exhibited approximately the same critical micelle concentration could differ substantially in the micelle size and shape depending on the chain rigidity. With the increase of surfactant concentration, primary micelles of more rigid molecules were found less keen to agglomeration and formation of nonspherical aggregates characteristic of flexible molecules.

  13. Are allergenic disperse dyes used for dyeing textiles?

    Science.gov (United States)

    Malinauskiene, Laura; Zimerson, Erik; Bruze, Magnus; Ryberg, Kristina; Isaksson, Marléne

    2012-09-01

    There are no data showing that disperse dyes, used to patch test patients, are currently being used for dyeing synthetic garments. It is unknown whether disperse dyes, which are currently routinely patch tested, are in fact present in synthetic textiles on the market. To determine whether eight disperse dyes, hitherto most widely cited as allergenic, are still used in textiles that are sold in various countries. Textiles from 13 countries in Europe, Asia and the United States were analysed. The procedure used for dye identification was thin-layer chromatography. When there were matching spots from the textile extract and reference dye, high-performance liquid chromatography was performed. Of 121 analysed items, three showed positive results for some of the investigated disperse dyes. Four dyes in these items could be detected and confirmed by the use of high-performance liquid chromatography. A pair of light brown ladies' tights manufactured and purchased in Italy contained Disperse Yellow 3, Disperse Blue 124, and Disperse Blue 106, and a set of black bra and panties purchased in India contained Disperse Orange 1. The eight disperse dyes that are most frequently incriminated in textile dye dermatitis are very rarely used in textiles nowadays. © 2012 John Wiley & Sons A/S.

  14. Poly(ethylene glycol) hydrogel microstructures encapsulating living cells

    Science.gov (United States)

    Koh, Won-Gun; Revzin, Alexander; Pishko, Michael V.

    2002-01-01

    We present an easy and effective method for the encapsulation of cells inside PEG-based hydrogel microstructures fabricated using photolithography. High-density arrays of three-dimensional microstructures were created on substrates using this method. Mammalian cells were encapsulated in cylindrical hydrogel microstructures of 600 and 50 micrometers in diameter or in cubic hydrogel structures in microfluidic channels. Reducing lateral dimension of the individual hydrogel microstructure to 50 micrometers allowed us to isolate 1-3 cells per microstructure. Viability assays demonstrated that cells remained viable inside these hydrogels after encapsulation for up to 7 days.

  15. Radiation synthesis and characterization of polyacrylic acid hydrogels

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pH-sensitive polyacrylic acid (PAA) hydrogels were synthesized by gamma-ray irradiation at an ambient temperature. The influences of dose, monomer concentration, cross-linking agent content, pH, and ionic strength on the swelling ratio (SR) of the PAA hydrogels were investigated in detail. The results show that the SR of the hydrogel decreases with an increase in the dose, monomer concentration, and cross-linking agent content. In alkaline solution, the SR of the hydrogels is much higher than that in acid solution. Also, the ionic strength can influence the SR of the hydrogels. The more the concentration, the lower the SR.

  16. Thermo-mechanical behavior of graphene oxide hydrogel

    Science.gov (United States)

    Ghosh, Rituparna; Deka Boruah, Buddha; Misra, Abha

    2017-02-01

    Graphene oxide hydrogel with encapsulated water presents a unique structural characteristic similar to open cell foam. It is demonstrated that the encapsulated water plays a vital role in tailoring compressive behavior of graphene oxide hydrogel under varying thermal conditions. The present study is focused on systematically evaluating both the temperature and frequency dependence on compressive behavior of hydrogel to elucidate the evolution of stiffness in a wider temperature range. The stiffness of the hydrogel is further tailored through encapsulation of nanoparticles to achieve an extraordinary enhancement in storage modulus. It is concluded that the change in phase of water provides a large gradient in the stiffness of the hydrogel.

  17. Macroporous hydrogels based on 2-hydroxyethyl methacrylate. Part III. Hydrogels as carriers for immobilization of proteins.

    Science.gov (United States)

    Michálek, J; Prádný, M; Artyukhov, A; Slouf, M; Smetana, K

    2005-08-01

    Four series of macroporous hydrogels based on crosslinked copolymers of 2-hydroxyethyl methacrylate (HEMA)-sodium methacrylate (MANa), copolymer HEMA-[2-(methacryloyloxy)ethyl]trimethylammonium chloride (MOETACl), terpolymer HEMA-MANa-MOETACl and on a polyelectrolyte complex were used as carriers for immobilization of proteins, chicken egg white albumin and avidin. The adsorption capacity of the hydrogels for the two proteins, kinetics and pH dependence of albumin adsorption and desorption were studied. The morphology of the hydrogels with and without immobilized albumin was studied by low-vacuum scanning electron microscopy.

  18. FY 1980 Report on Dye Laser Materials

    Science.gov (United States)

    1981-02-01

    by block number) Dye Lasers Laser Dyes Tunable Lasers Photodegradation Rhodamine Dyes 20. ABSTRACT (Continue n resld* it necesiry and Identify by block...limited usefulness as a portable military device because of the photodegradation of the dye solution. Although there have been state-of-the-art reviews...on laser dyes , 1𔃼 the photodegradation of laser dyes ,3 and dye lasers, 4- 6 only authors from, or funded by, military organizations have given strict

  19. Effects of architecture on the stability of thermosensitive unimolecular micelles.

    Science.gov (United States)

    Steinschulte, Alexander A; Schulte, Bjoern; Rütten, Stephan; Eckert, Thomas; Okuda, Jun; Möller, Martin; Schneider, Stefanie; Borisov, Oleg V; Plamper, Felix A

    2014-03-14

    The influence of architecture on polymer interactions is investigated and differences between branched and linear copolymers are found. A comprehensive picture is drawn with the help of a fluorescence approach (using pyrene and 4HP as probe molecules) together with IR or NMR spectroscopy and X-ray/light scattering measurements. Five key aspects are addressed: (1) synergistic intramolecular complexation within miktoarm stars. The proximity of thermoresponsive poly(propylene oxide) (PPO) and poly(dimethylaminoethyl methacrylate) (PDMAEMA) within a miktoarm star leads to complexation between these weakly interacting partners. Consequently, the original properties of the constituents are lost, showing hydrophobic domains even at low temperatures, at which all homopolymers are water soluble. (2) Unimolecular micelles for miktoarm stars. The star does not exhibit intermolecular self-assembly in a large temperature range, showing unimers up to 55 °C. This behavior was traced back to a reduced interfacial tension between the PPO-PDMAEMA complex and water (PDMAEMA acts as a "microsurfactant"). (3) Unimolecular to multimolecular micelle transition for stars. The otherwise stable unimolecular micelles self-assemble above 55 °C. This aggregation is not driven by PPO segregation, but by collapse of residual PDMAEMA. This leads to micrometer-sized multilamellar vesicles stabilized by poly(ethylene oxide) (PEO). (4) Prevention of pronounced complexation within diblock copolymers. In contrast to the star copolymers, PPO and PDMAEMA adapt rather their homopolymer behavior within the diblock copolymers. Then they show their immanent LCST properties, as PDMAEMA turns insoluble at elevated temperatures, whereas PPO becomes hydrophobic below room temperature. (5) Two-step micellization for diblock copolymers. Upon heating of linear copolymers, the dehydration of PPO is followed by self-assembly into spherical micelles. An intermediate prevalence of unimolecular micelles is revealed

  20. Two distinct mechanisms of vesicle-to-micelle and micelle-to-vesicle transition are mediated by the packing parameter of phospholipid-detergent systems

    NARCIS (Netherlands)

    Stuart, Marc C. A.; Boekema, Egbert J.

    2007-01-01

    The detergent solubilization and reformation of phospholipid vesicles was studied for various detergents. Two distinct mechanisms of vesicle-to-micelle and micelle-to-vesicle transition were observed by turbidimetry and cryo-electron microscopy. The first mechanism involves fast solubilization of ph

  1. Plantas Tintureiras Dye Plants

    Directory of Open Access Journals (Sweden)

    Maria do Carmo Serrano

    2008-12-01

    Full Text Available Existe uma vasta bibliografia, até ao séc. XVIII, sobre plantas produtoras de corantes naturais, sendo que apenas um número limitado foi utilizado no tingimento de têxteis antigos, devido à capacidade de resistência à lavagem e ao desvanecimento. O cultivo de plantas ou a sua existência no mundo silvestre tiveram uma enorme importância sócio-económica para muitas comunidades espalhadas pelo mundo e pelas intensas trocas comerciais que geraram. A extracção dos corantes era feita a partir de diferentes partes de plantas ou árvores. Nalgumas plantas eram utilizadas as folhas, enquanto noutras se aproveitavam as flores, as raízes, os frutos, troncos ou sementes. Os corantes podiam ser extraídos através de processos complexos que envolviam diversas operações como maceração, destilação, fermentação, decantação, precipitação, filtração, etc. Neste âmbito, são apresentadas algumas das plantas cultivadas em Portugal e em muitos outros países europeus e que foram usadas em tinturaria. Este trabalho pretende ser um contributo para obstar à perda de conhecimentos das condições de cultivo e da forma como se maximizava a produção de corantes.A vast bibliography exists, until the 18th cen-tury, on natural dyes obtained from plants, but only one limited number was used in the dyeing of old textiles, due to capacity of resistance to wash and light fading. The culture of plants or its existence in the wild world had an enormous economical importance for many communities spread for the world, and the intense commercial exchanges that had generated. The extraction of dyes was done from different parts of plants or trees. In some plants was used the leaves, others, only the roots, the fruits, trunks or seeds. The dyes could be extracted through complex processes that involved various operations as maceration, distillation, fermentation, decantation, precipitation, filtration, etc. In this scope, some of the plants cultivated in

  2. Hydrogels: a journey from diapers to gene delivery.

    Science.gov (United States)

    Chawla, Pooja; Srivastava, Alok Ranjan; Pandey, Priyanka; Chawla, Viney

    2014-02-01

    Hydrogels are the biomaterials comprising network of natural or synthetic polymers capable of absorbing large amount of water. Hydrogels are "Smart Gels" or "Intelligent Gels" which can be made to respond to the various environmental conditions like temperature, pH, magnetic/electric field, ionic strength, inflammation, external stress etc. There are numerous potential applications of hydrogels in modern day life ranging from a diaper to gene delivery. This review succinctly describes the classification, properties and preparation methods along with numerous diverse applications of hydrogels like agricultural hydrogels, hydrogel for drug delivery, sensing, dental adhesives, wound healing and tissue regeneration, diet aid and gastric retention and in tissue engineering etc. Hydrogels can be regarded as highly valuable biomaterials for human-beings.

  3. Commercialization of hydrogel for topical anesthesia by irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nho, Youngchang; Kang, Philhyun; Lim, Younmook; Gwon, Huijeong; Park, Jongseok

    2013-09-15

    - The technologies to develop topical asesthetic hydrogels were developed and the preliminary clinical test was carried out for the prepared hydrogels at Kyunghee University. - The topical asesthetic hydrogels made by radiation are founded to have appropriate strengths and accelerant delivery behavior for lidocane which has a function of anesthetic. - New type of Hydrogels were designed in these experiments so that they had voids in hydrogels which led to much more absorption of exudate. - Several companies and Philippine Nuclear Research Institute(PNRI) are interested in our technologies to produce the hydrogels, we signed a MOA to support PNRI technically in the field of hydrogels and perform the general technical cooperation between Advanced Radiation Technology and PNRI.

  4. pH-Sensitive Hydrogel for Micro-Fluidic Valve

    Directory of Open Access Journals (Sweden)

    Zhengzhi Yang

    2012-07-01

    Full Text Available The deformation behavior of a pH-sensitive hydrogel micro-fluidic valve system is investigated using inhomogeneous gel deformation theory, in which the fluid-structure interaction (FSI of the gel solid and fluid flow in the pipe is considered. We use a finite element method with a well adopted hydrogel constitutive equation, which is coded in commercial software, ABAQUS, to simulate the hydrogel valve swelling deformation, while FLUENT is adopted to model the fluid flow in the pipe of the hydrogel valve system. The study demonstrates that FSI significantly affects the gel swelling deformed shapes, fluid flow pressure and velocity patterns. FSI has to be considered in the study on fluid flow regulated by hydrogel microfluidic valve. The study provides a more accurate and adoptable model for future design of new pH-sensitive hydrogel valves, and also gives a useful guideline for further studies on hydrogel fluidic applications.

  5. Radiation processed hydrogel of poly (vinyl alcohol) with biodegradable polysaccharides.

    Science.gov (United States)

    Chowdhury, M N K; Alam, A K M M; Dafader, N C; Haque, M E; Akhtar, F; Ahmed, M U; Rashid, H; Begum, R

    2006-01-01

    Poly(vinyl alcohol) (PVA) can be modified to polymer hydrogels by radiation crosslinking and can be used in different biomedical applications. A study was done on the optimization of ingredients concentration for preparing good quality PVA hydrogels with natural polysaccharides. The synthesized hydrogels were also characterized by measuring the different physical properties e.g. gel fraction, swelling and absorption rate. Besides these, sterility test were also performed. Good quality hydrogels were obtained from PVA and natural polysaccharides solutions with 27 kGy radiation dose. There is an influence of natural polysaccharides on the gel fraction of hydrogel. The increase in the amount of polysaccharide causes a decrease in gel fraction that is decrease in the crosslinking density of PVA hydrogel network. The prepared hydrogels were found to be sterile.

  6. Thermoresponsive chitosan-agarose hydrogel for skin regeneration.

    Science.gov (United States)

    Miguel, Sónia P; Ribeiro, Maximiano P; Brancal, Hugo; Coutinho, Paula; Correia, Ilídio J

    2014-10-13

    Healing enhancement and pain control are critical issues on wound management. So far, different wound dressings have been developed. Among them, hydrogels are the most applied. Herein, a thermoresponsive hydrogel was produced using chitosan (deacetylation degree 95%) and agarose. Hydrogel bactericidal activity, biocompatibility, morphology, porosity and wettability were characterized by confocal microscopy, MTS assay and SEM. The performance of the hydrogel in the wound healing process was evaluated through in vivo assays, during 21 days. The attained results revealed that hydrogel has a pore size (90-400 μm) compatible with cellular internalization and proliferation. A bactericidal activity was observed for hydrogels containing more than 188 μg/mL of chitosan. The improved healing and the lack of a reactive or a granulomatous inflammatory reaction in skin lesions treated with hydrogel demonstrate its suitability to be used in a near future as a wound dressing.

  7. Antimicrobial hydrogels for the treatment of infection.

    Science.gov (United States)

    Veiga, Ana Salomé; Schneider, Joel P

    2013-11-01

    The increasing prevalence of microbial infections, especially those associated with impaired wound healing and biomedical implant failure has spurred the development of new materials having antimicrobial activity. Hydrogels are a class of highly hydrated material finding use in diverse medical applications such as drug delivery, tissue engineering, as wound fillers, and as implant coatings, to name a few. The biocompatible nature of many gels make them a convenient starting platform to develop selectively active antimicrobial materials. Hydrogels with antimicrobial properties can be obtained through the encapsulation or covalent immobilization of known antimicrobial agents, or the material itself can be designed to possess inherent antimicrobial activity. In this review we present an overview of antimicrobial hydrogels that have recently been developed and when possible provide a discussion relevant to their mechanism of action.

  8. Controlled Angiogenesis in Peptide Nanofiber Composite Hydrogels.

    Science.gov (United States)

    Wickremasinghe, Navindee C; Kumar, Vivek A; Shi, Siyu; Hartgerink, Jeffrey D

    2015-09-14

    Multidomain peptide (MDP) nanofibers create scaffolds that can present bioactive cues to promote biological responses. Orthogonal self-assembly of MDPs and growth-factor-loaded liposomes generate supramolecular composite hydrogels. These composites can act as delivery vehicles with time-controlled release. Here we examine the controlled release of placental growth factor-1 (PlGF-1) for its ability to induce angiogenic responses. PlGF-1 was loaded either in MDP matrices or within liposomes bound inside MDP matrices. Scaffolds showed expected rapid infiltration of macrophages. When released through liposomes incorporated in MDP gels (MDP(Lipo)), PlGF-1 modulates HUVEC VEGF receptor activation in vitro and robust vessel formation in vivo. These loaded MDP(Lipo) hydrogels induce a high level of growth-factor-mediated neovascular maturity. MDP(Lipo) hydrogels offer a biocompatible and injectable platform to tailor drug delivery and treat ischemic tissue diseases.

  9. Synthesis and characterization of anisotropic magnetic hydrogels

    Science.gov (United States)

    Hinrichs, Stephan; Nun, Nils; Fischer, Birgit

    2017-06-01

    Multiresponsive hydrogels are an interesting new class of materials. They offer the advantage, that they respond to different stimuli like temperature, pH and magnetic fields. By this they can change their properties which makes the hydrogels ideal candidates for many applications in the technical as well as medical field. Here we present the synthesis and characterization of hydrogels - micro- as well as macrogels - which consist of an iron oxide core, varying in phase and morphology, embedded in a thermoresponsive polymer, consisting of poly N-isopropylacrylamide. By using dynamic light scattering we investigated the thermoresponsive properties. In addition we were able to follow the formation of the macrogel by monitoring the shear viscosity.

  10. Synthesis of azo pyridone dyes

    Directory of Open Access Journals (Sweden)

    Mijin Dušan Ž.

    2011-01-01

    Full Text Available Over 50% of all colorants which are used nowdays are azo dyes and pigments, and among them arylazo pyridone dyes (and pigments have became of interest in last several decades due to the high molar extinction coefficient, and the medium to high light and wet fastness properties. They find application generally as disperse dyes. The importance of disperse dyes increased in the 1970s and 1980s due to the use of polyester and nylon as the main synthetic fibers. Also, disperse dyes were used rapidly since 1970 in inks for the heat-transfer printing of polyester. The main synthetic route for the preparation of azo dyes is coupling reaction between an aromatic diazo compound and a coupling component. Of all dyes manufactured, about 60% are produced by this reaction. Arylazo pyridone dyes can be prepared from pyridone moiety as a coupling component, where substituent can be on nitrogen, and diazonim salts which can be derived from different substituted anilines or other heterocyclic derivatives. In addition, arylazo dyes containing pyridone ring can be prepared from arylazo diketones or arylazo ketoesters (obtained by coupling β-diketones or β-ketoesters with diazonim salts by condensation with cyanoacetamide. Disazo dyes can be prepared by tetrazotizing a dianiline and coupling it with a pyridone or by diazotizing aniline and coupling it with a dipyridone. Trisazo dyes can be also prepared by diazotizing of aniline and coupling it with a tripyridone or by hexazotizing a trianiline and coupling it with a pyridone. The main goal of this paper is to give a brief review on the synthesis of arylazo pyridone dyes due to the lack of such reviews. In addition, some properties of arylazo pyridone dyes as light fastness and azo-hydrazon tautomerism are disccused.

  11. Formation of wormlike micelles in anionic surfactant AES aqueous solutions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The growth and structure of anionic micelles of sodium dodecyl trioxyethylene sulfate (AES) in the presence 3+of multivalent counterion Al were investigated by means of dynamic rheological methods. It has been obtained by the measurements of shear viscosity, complex viscosity and dynamic moduli, as well as the application of Cox-Merz rule and Cole-Cole plot that wormlike micelle and network structure could be formed in AES/AlCl3 aqueous solutions.The structure was of a character of nonlinear viscoelastic fluid and departure from the simple Maxwell model. The technique of freeze-fracture transmission electron microscopy (FF-TEM) was also used to confirm the formation of this interesting structure.``

  12. Large magnetic anisotropy in ferrihydrite nanoparticles synthesized from reverse micelles

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, E L [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, Sao Paulo, 05315-970 (Brazil); Itri, R [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, Sao Paulo, 05315-970 (Brazil); Jr, E Lima [Instituto de Fisica, Universidade de Sao Paulo, CP 66318, Sao Paulo, 05315-970 (Brazil); Baptista, M S [Instituto de Quimica, Universidade de Sao Paulo, Avenida Professor Lineu Prestes 748, Sao Paulo (Brazil); Berquo, T S [Institute for Rock Magnetism, University of Minnesota, 100 Union Street SE, Minneapolis, MN 55455-0128 (United States); Goya, G F [Instituto de Nanociencias de Aragon (INA), Universidad de Zaragoza, Pedro Cerbuna 12 (50009), Zaragoza (Spain)

    2006-11-28

    Six-line ferrihydrite (FH) nanoparticles have been synthesized in the core of reverse micelles, used as nanoreactors to obtain average particle sizes {approx} 2-4 nm. The blocking temperatures T{sub B}{sup m} extracted from magnetization data increased from {approx}10 to 20 K for increasing particle size. Low-temperature Moessbauer measurements allowed us to observe the onset of differentiated contributions from the particle core and surface as the particle size increases. The magnetic properties measured in the liquid state of the original emulsion showed that the ferrihydrite phase is not present in the liquid precursor, but precipitates in the micelle cores after the free water is freeze-dried. Systematic susceptibility {chi}{sub ac}(f,T) measurements showed the dependence of the effective magnetic anisotropy energies E{sub a} with particle volume, and yielded an effective anisotropy value of K{sub eff} = 312 {+-} 10 kJ m{sup -3}.

  13. Dyeing fabrics with metals

    Science.gov (United States)

    Kalivas, Georgia

    2002-06-01

    Traditionally, in textile dyeing, metals have been used as mordants or to improve the color produced by a natural or synthetic dye. In biomedical research and clinical diagnostics gold colloids are used as sensitive signals to detect the presence of pathogens. It has been observed that when metals are finely divided, a distinct color may result that is different from the color of the metal in bulk. For example, when gold is finely divided it may appear black, ruby or purple. This can be seen in biomedical research when gold colloids are reduced to micro-particles. Bright color signals are produced by few nanometer-sized particles. Dr. William Todd, a researcher in the Department of Veterinary Science at the Louisiana State University, developed a method of dyeing fabrics with metals. By using a reagent to bond the metal particles deep into the textile fibers and actually making the metal a part of the chemistry of the fiber. The chemicals of the fabric influence the resulting color. The combination of the element itself, the size of the particle, the chemical nature of the particle and the interaction of the metal with the chemistry of the fabric determine the actual hue. By using different elements, reagents, textiles and solvents a broad range of reproducible colors and tones can be created. Metals can also be combined into alloys, which will produce a variety of colors. The students of the ISCC chapter at the Fashion Institute of Technology dyed fabric using Dr. Todd's method and created a presentation of the results. They also did a demonstration of dyeing fabrics with metals.

  14. Injectable silk-polyethylene glycol hydrogels.

    Science.gov (United States)

    Wang, Xiaoqin; Partlow, Benjamin; Liu, Jian; Zheng, Zhaozhu; Su, Bo; Wang, Yansong; Kaplan, David L

    2015-01-01

    Silk hydrogels for tissue repair are usually pre-formed via chemical or physical treatments from silk solutions. For many medical applications, it is desirable to utilize injectable silk hydrogels at high concentrations (>8%) to avoid surgical implantation and to achieve slow in vivo degradation of the gel. In the present study, injectable silk solutions that formed hydrogels in situ were generated by mixing silk with low-molecular-weight polyethylene glycol (PEG), especially PEG300 and 400 (molecular weight 300 and 400g mol(-1)). Gelation time was dependent on the concentration and molecular weight of PEG. When the concentration of PEG in the gel reached 40-45%, gelation time was less than 30min, as revealed by measurements of optical density and rheological studies, with kinetics of PEG400 faster than PEG300. Gelation was accompanied by structural changes in silk, leading to the conversion from random coil in solution to crystalline β-sheets in the gels, based on circular dichroism, attenuated total reflection Fourier transform infrared spectroscopy and X-ray diffraction. The modulus (127.5kPa) and yield strength (11.5kPa) determined were comparable to those of sonication-induced hydrogels at the same concentrations of silk. The time-dependent injectability of 15% PEG-silk hydrogel through 27G needles showed a gradual increase of compression forces from ∼10 to 50N within 60min. The growth of human mesenchymal stem cells on the PEG-silk hydrogels was hindered, likely due to the presence of PEG, which grew after a 5 day delay, presumably while the PEG solubilized away from the gel. When 5% PEG-silk hydrogel was subcutaneously injected in rats, significant degradation and tissue in-growth took place after 20 days, as revealed by ultrasound imaging and histological analysis. No significant inflammation around the gel was observed. The features of injectability, slow degradation and low initial cell attachment suggests that these PEG-silk hydrogels are of interest

  15. Application of hydrogel system for neutron attenuation

    CERN Document Server

    Gupta, S C; Gupta, B P

    2000-01-01

    Hydrogel sheets based on poly(vinyl alcohol) (PVA) and poly(vinyl acetate) (PVAc) have been prepared by the technique of acetalization of PVA using formaldehyde and grafting of acrylic acid onto PVAc by gamma irradiation. PVA hydrogel (PVAB) sheets have been prepared in geometrically stable shapes by compression moulding process and characterised for their thermal properties, geometrical stability on water absorption, and neutron shielding efficiency. The effective protection from fast neutrons can be increased by a factor of 18% by swelling the PVAB sheets to 210% in water. The water intake and subsequent retention of water by the sheet can be tailored as per shielding requirements.

  16. Biosensors with reversed micelle-enzyme sensitive membrane

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effect of reversed micelle on the conformation of enzyme was studied by sensor techniques. By means of measurement of the response current of GOD enzyme membrane electrode, the effects of enzyme embedded in AOT reversed micellar on GOD conformation and catalytic activity are discussed. The results show that the response current increased greatly with decreasing ratio of GOD/AOT, meaning that the catalytic activity and the conformation stability of enzyme were enhanced.

  17. The synthesis of hydrogels with controlled distribution of polymer brushes in hydrogel network

    Energy Technology Data Exchange (ETDEWEB)

    Sun, YuWei; Zhou, Chao; Zhang, AoKai; Xu, LiQun; Yao, Fang [School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province, 211189 (China); Cen, Lian, E-mail: cenlian@hotmail.com [National Tissue Engineering Center of China, No.68, East Jiang Chuan Road, Shanghai, 200241 (China); School of Chemical Engineering, East China University of Science and Technology, No.130, Mei Long Road, Shanghai, 200237 (China); Fu, Guo-Dong, E-mail: fu7352@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Jiangning District, Nanjing, Jiangsu Province, 211189 (China)

    2014-11-30

    Highlights: • Many biological tissues are 3-dimensionally asymmetric in structure and properties, it would be desirable if hydrogels could bear such structural similarity with specialized surface and bulk properties. Moreover, gradual but continuous variation in spatial structural and property is also a common phenomenon in biological tissues, such as interfaces between bone and tendon, or between bone and cartilage. Hence, the development of a method to introduce well-defined functional polymer brushes on PEG hydrogels, especially with precisely controlled spatial structure in 3-dimensions, would impart the hydrogels with special functionalities and wider applications. Poly(ethylene glycol) (PEG) hydrogels with 3-dimensionally controlled well-defined poly(N-isopropylacrylamide) (poly(NIPAAm)) brushes were prepared by combined copper(I)-catalyzed azide-alkyne cycloaddition (“Click Chemistry”) and atom transfer radical polymerization (ATRP). The resulting hydrogels were presented as representatives with their detailed synthesis routes and characterization. H{sub PEG}-S-poly(NIPAAm) is a hydrogel with poly(NIPAAm) brushes mainly grafted on surface, whereas H{sub PEG}-G-poly(NIPAAm) has a gradiently decreased poly(NIPAAm) brushes in their chain length from surface to inside. On the other hand, poly(NIPAAm) brushes in H{sub PEG}-U-poly(NIPAAm) are uniformly dispersed throughout the whole hydrogel network. Successful preparation of H{sub PEG}-S-poly(NIPAAm), H{sub PEG}-G-poly(NIPAAm) and H{sub PEG}-U-poly(NIPAAm) were ascertained by X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. Hence, the flexibility and controllability of the synthetic strategy in varying the distribution of polymer brushes and hydrogel surface properties was demonstrated. Hydrogels with tunable and well-defined 3-dimensional poly(NIPAAm) polymer brushes could be tailor-designed to find potential applications in smart devices or skin dressing, such as for diabetics

  18. Gold-Loaded Polymeric Micelles with Temperature-Modulated Catalytic Activity

    Institute of Scientific and Technical Information of China (English)

    HU Na; SHI Dongjian; LI Jihang; LI Junfeng; CHEN Mingqing

    2015-01-01

    Four-armed amphiphilic block copolymers, polystyrene-b-poly(N-isopropylacrylamide) (PS-b-PNIPAM)4, were synthesized by atom transfer radical polymerization (ATRP). (PS-b-PNIPAM)4 self-assembled into micelles with PS block as core and thermoresponsive PNIPAM block as corona. The gold nanoparticles (Au NPs) with average diameter about 5.8 nm were immobilized on the surfaces of the micelles by the reduction of the corresponding ions. The micelle-supported gold nanoparticles (Au-micelles) were applied to catalyze the reduction ofp-nitrophenol. Moreover, the activity of the Au-micelle catalyst could be modulated by the temperature and the Au-micelles could be easily recovered by changing the temperature and recycled four times with high catalytic activity.

  19. Construction of the Active Site of Metalloenzyme on Au NC Micelles

    Institute of Scientific and Technical Information of China (English)

    ZHANG, Zhiming; FU, Qiuan; HUANG, Xin; XU, Jiayun; LIU, Junqiu; SHEN, Jiacong

    2009-01-01

    For developing an efficient nanoenzyme system with self-assembly strategy, gold nanocrystal micelles (Au NC micelles) with inserted catalytic Zn(Ⅱ) centers were constructed by self-assembly of a catalytic ligand [N,N-bis(2-aminoethyl)-N'dodecylethylenediamine] Zn(Ⅱ) complexes (Zn(Ⅱ)L) on the surface of Au NC via hy- drophobic interaction. The functionalized Au NC micelles acted as an excellent nanoenzyme model for imitating ribonuclease. The catalytic capability of the Au NC micelles was evaluated by accelerating the cleavage of 2-hydroxypropyl p-nitrophenyl phosphate (HPNP). These functionalized Au NC micelles exhibited considerable ri- bonuclease-like activities by a factor of 4.9×104 (kcat/kuncat) for the cleavage of HPNP in comparison to the sponta- neous cleavage of HPNP at 37℃. The catalytic capability of the functionalized Au NC micelles can be considera- bly compared to other models reported previously as nanoenzymes under the comparable conditions.

  20. Development of the simple and sensitive method for lipoxygenase assay in AOT/isooctane reversed micelles.

    Science.gov (United States)

    Park, Kyung Min; Kim, Yu Na; Choi, Seung Jun; Chang, Pahn-Shick

    2013-06-01

    In this study, we investigated the possibility of reversed micelles, widely used as an enzyme reactor for lipases, for the determination of lipoxygenase activity. Although it is rapid and simple, reversed micelles have some limitations, such as interference by UV-absorbing materials and surfactant. Lipoxygenase activity in the reversed micelles was determined by reading the absorbance of the lipid hydroperoxidation product (conjugated diene) at 234 nm. Among surfactants and organic media, AOT and isooctane were most effective for the dioxygenation of linoleic acid in reversed micelles. The strong absorbance of AOT in the UV region is a major obstacle for the direct application of the AOT/isooctane reversed micelles to lipoxygenase activity determination. To prevent interference by AOT, we added an AOT removal step in the procedure for lipoxygenase activity determination in reversed micelles. The lipoxygenase activity was dependent on water content, and maximum activity was obtained at an R-value of 10.

  1. Laser dye stability. Pt. 3. Bicyclic dyes in ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, A.N. (Naval Weapons Center, China Lake, Calif. (USA). Research Dept.)

    1977-11-01

    A commercial coaxial xenon flashlamp has been used to evaluate the stability of a variety of coumarin and quinolone laser dyes. The lasing characteristics of over 30 dyes have been quantitatively evaluated as a function of the total excitation energy to which recirculating dye solution has been exposed. Degradation constants were determined an an evaluation was made of the effects of functional group variation upon the stability of the dyes. Comparison with the data of other workers revealed that exclusion of excitation energy below 220 nm does not change the stability of 4-methyl coumarins, but can increase the stability of other coumarins as much as 50 fold.

  2. Predicting proton titration in cationic micelle and bilayer environments

    Energy Technology Data Exchange (ETDEWEB)

    Morrow, Brian H.; Shen, Jana K. [Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201 (United States); Eike, David M.; Murch, Bruce P.; Koenig, Peter H. [Computational Chemistry, Modeling and Simulation GCO, Procter and Gamble, Cincinnati, Ohio 45201 (United States)

    2014-08-28

    Knowledge of the protonation behavior of pH-sensitive molecules in micelles and bilayers has significant implications in consumer product development and biomedical applications. However, the calculation of pK{sub a}’s in such environments proves challenging using traditional structure-based calculations. Here we apply all-atom constant pH molecular dynamics with explicit ions and titratable water to calculate the pK{sub a} of a fatty acid molecule in a micelle of dodecyl trimethylammonium chloride and liquid as well as gel-phase bilayers of diethyl ester dimethylammonium chloride. Interestingly, the pK{sub a} of the fatty acid in the gel bilayer is 5.4, 0.4 units lower than that in the analogous liquid bilayer or micelle, despite the fact that the protonated carboxylic group is significantly more desolvated in the gel bilayer. This work illustrates the capability of all-atom constant pH molecular dynamics in capturing the delicate balance in the free energies of desolvation and Coulombic interactions. It also shows the importance of the explicit treatment of ions in sampling the protonation states. The ability to model dynamics of pH-responsive substrates in a bilayer environment is useful for improving fabric care products as well as our understanding of the side effects of anti-inflammatory drugs.

  3. Polymeric micelles encapsulating photosensitizer: structure/photodynamic therapy efficiency relation.

    Science.gov (United States)

    Gibot, Laure; Lemelle, Arnaud; Till, Ugo; Moukarzel, Béatrice; Mingotaud, Anne-Françoise; Pimienta, Véronique; Saint-Aguet, Pascale; Rols, Marie-Pierre; Gaucher, Mireille; Violleau, Frédéric; Chassenieux, Christophe; Vicendo, Patricia

    2014-04-14

    Various polymeric micelles were formed from amphiphilic block copolymers, namely, poly(ethyleneoxide-b-ε-caprolactone), poly(ethyleneoxide-b-d,l-lactide), and poly(ethyleneoxide-b-styrene). The micelles were characterized by static and dynamic light scattering, electron microscopy, and asymmetrical flow field-flow fractionation. They all displayed a similar size close to 20 nm. The influence of the chemical structure of the block copolymers on the stability upon dilution of the polymeric micelles was investigated to assess their relevance as carriers for nanomedicine. In the same manner, the stability upon aging was assessed by FRET experiments under various experimental conditions (alone or in the presence of blood proteins). In all cases, a good stability over 48 h for all systems was encountered, with PDLLA copolymer-based systems being the first to release their load slowly. The cytotoxicity and photocytotoxicity of the carriers were examined with or without their load. Lastly, the photodynamic activity was assessed in the presence of pheophorbide a as photosensitizer on 2D and 3D tumor cell culture models, which revealed activity differences between the 2D and 3D systems.

  4. Hydrotropy: monomer-micelle equilibrium and minimum hydrotrope concentration.

    Science.gov (United States)

    Shimizu, Seishi; Matubayasi, Nobuyuki

    2014-09-01

    Drug molecules with low aqueous solubility can be solubilized by a class of cosolvents, known as hydrotropes. Their action has often been explained by an analogy with micelle formation, which exhibits critical micelle concentration (CMC). Indeed, hydrotropes also exhibit "minimum hydrotrope concentration" (MHC), a threshold concentration for solubilization. However, MHC is observed even for nonaggregating monomeric hydrotropes (such as urea); this raises questions over the validity of this analogy. Here we clarify the effect of micellization on hydrotropy, as well as the origin of MHC when micellization is not accompanied. On the basis of the rigorous Kirkwood-Buff (KB) theory of solutions, we show that (i) micellar hydrotropy is explained also from preferential drug-hydrotrope interaction; (ii) yet micelle formation reduces solubilization effeciency per hydrotrope molecule; (iii) MHC is caused by hydrotrope-hydrotrope self-association induced by the solute (drug) molecule; and (iv) MHC is prevented by hydrotrope self-aggregation in the bulk solution. We thus need a departure from the traditional view; the structure of hydrotrope-water mixture around the drug molecule, not the structure of the aqueous hydrotrope solutions in the bulk phase, is the true key toward understanding the origin of MHC.

  5. Micelles and nanoparticles for ultrasonic drug and gene delivery.

    Science.gov (United States)

    Husseini, Ghaleb A; Pitt, William G

    2008-06-30

    Drug delivery research employing micelles and nanoparticles has expanded in recent years. Of particular interest is the use of these nanovehicles that deliver high concentrations of cytotoxic drugs to diseased tissues selectively, thus reducing the agent's side effects on the rest of the body. Ultrasound, traditionally used in diagnostic medicine, is finding a place in drug delivery in connection with these nanoparticles. In addition to their non-invasive nature and the fact that they can be focused on targeted tissues, acoustic waves have been credited with releasing pharmacological agents from nanocarriers, as well as rendering cell membranes more permeable. In this article, we summarize new technologies that combine the use of nanoparticles with acoustic power both in drug and gene delivery. Ultrasonic drug delivery from micelles usually employs polyether block copolymers and has been found effective in vivo for treating tumors. Ultrasound releases drug from micelles, most probably via shear stress and shock waves from the collapse of cavitation bubbles. Liquid emulsions and solid nanoparticles are used with ultrasound to deliver genes in vitro and in vivo. The small packaging allows nanoparticles to extravasate into tumor tissues. Ultrasonic drug and gene delivery from nanocarriers has tremendous potential because of the wide variety of drugs and genes that could be delivered to targeted tissues by fairly non-invasive means.

  6. Chain exchange kinetics of block copolymer micelles in ionic liquids

    Science.gov (United States)

    Ma, Yuanchi; Lodge, Timothy

    The chain exchange kinetics of block copolymer micelles has been studied using time-resolved small-angle neutron scattering (TR-SANS), a key tool in determining the average micelle composition in contrast-matched solvents. In this work, PMMA-block-PnBMA was selected as the model block copolymer, which has a LCST behavior in the common ionic liquids, [EMIM][TFSI] and [BMIM][TFSI]. We examined the chain exchange kinetics of three PMMA-block-PnBMA copolymers, with identical PMMA block length (MPMMA = 25000) and different PnBMA block lengths (MPnBMA = 24000, 35000 and 53000); the Flory-Huggins interaction parameter (χ) between the core (PnBMA) and the solvent were varied by mixing [EMIM][TFSI] and [BMIM][TFSI] in different ratios. We found that the relaxation of the initial segregation of h- and d- micelles followed the same form with the time as previously developed by our group. Assuming that single chain expulsion is the rate limiting step, the thermal barrier was found to depend linearly on the core block length (Ncore) . Furthermore, the effect of χ on the chain exchange kinetics will also be discussed.

  7. Enhancing oral bioavailability of quercetin using novel soluplus polymeric micelles

    Science.gov (United States)

    Dian, Linghui; Yu, Enjiang; Chen, Xiaona; Wen, Xinguo; Zhang, Zhengzan; Qin, Lingzhen; Wang, Qingqing; Li, Ge; Wu, Chuanbin

    2014-12-01

    To improve its poor aqueous solubility and stability, the potential chemotherapeutic drug quercetin was encapsulated in soluplus polymeric micelles by a modified film dispersion method. With the encapsulation efficiency over 90%, the quercetin-loaded polymeric micelles (Qu-PMs) with drug loading of 6.7% had a narrow size distribution around mean size of 79.00 ± 2.24 nm, suggesting the complete dispersibility of quercetin in water. X-ray diffraction (XRD) patterns illustrated that quercetin was in amorphous or molecular form within PMs. Fourier transform infrared spectroscopy (FTIR) indicated that quercetin formed intermolecular hydrogen bonding with carriers. An in vitro dialysis test showed the Qu-PMs possessed significant sustained-release property, and the formulation was stable for at least 6 months under accelerated conditions. The pharmacokinetic study in beagle dogs showed that absorption of quercetin after oral administration of Qu-PMs was improved significantly, with a half-life 2.19-fold longer and a relative oral bioavailability of 286% as compared to free quercetin. Therefore, these novel soluplus polymeric micelles can be applied to encapsulate various poorly water-soluble drugs towards a development of more applicable therapeutic formulations.

  8. Cold Pad-Batch dyeing method for cotton fabric dyeing with reactive dyes using ultrasonic energy.

    Science.gov (United States)

    Khatri, Zeeshan; Memon, Muhammad Hanif; Khatri, Awais; Tanwari, Anwaruddin

    2011-11-01

    Reactive dyes are vastly used in dyeing and printing of cotton fibre. These dyes have a distinctive reactive nature due to active groups which form covalent bonds with -OH groups of cotton through substitution and/or addition mechanism. Among many methods used for dyeing cotton with reactive dyes, the Cold Pad Batch (CPB) method is relatively more environment friendly due to high dye fixation and non requirement of thermal energy. The dyed fabric production rate is low due to requirement of at least twelve hours batching time for dye fixation. The proposed CPB method for dyeing cotton involves ultrasonic energy resulting into a one third decrease in batching time. The dyeing of cotton fibre was carried out with CI reactive red 195 and CI reactive black 5 by conventional and ultrasonic (US) method. The study showed that the use of ultrasonic energy not only shortens the batching time but the alkalis concentrations can considerably be reduced. In this case, the colour strength (K/S) and dye fixation (%F) also enhances without any adverse effect on colour fastness of the dyed fabric. The appearance of dyed fibre surface using scanning electron microscope (SEM) showed relative straightening of fibre convolutions and significant swelling of the fibre upon ultrasonic application. The total colour difference values ΔE (CMC) for the proposed method, were found within close proximity to the conventionally dyed sample.

  9. Microwave-assisted Palladium-micelle-catalyzed Suzuki Cross-coupling Reaction in Water

    Institute of Scientific and Technical Information of China (English)

    LIN Li; LI Sheng-hai; JIANG Ri-hua

    2011-01-01

    A microwave-accelerated Suzuki coupling procedure was developed via guanidinium ionic liquids(GILs)stabilized Pd-micelle.The Pd micelle/GILs play a key role in enhancing the activity,due to the highly dispersed Pd active sites and the phase transfer function of GILs,which ensures the adsorption of reactants and facilitates the translation of the intermediates to the surface of the micelle.

  10. Effect of Micelle Composition on Acidic Drugs Separation Behavior by Micellar Electrokinetic Capillary Chromatography

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Micellar electrokinetic capillary chromatography (MECC) separation of four acidic drugs similar in structure was studied. Both anionic surfactant sodium dodecyl sulfate (SDS) and nonionic surfactant Tween 20 were used to form single micelles and mixed micelles as pseudostationary phases. The effects of the composition of micellar solution on retention behaviors were studied. The results indicate that there is markedly different selectivity among SDS, Tween 20 and the mixed micelles systems.

  11. Structure of phosphate fluorosurfactant based reverse micelles in supercritical carbon dioxide

    OpenAIRE

    Senapati, S; Keiper, J. S.; de Simone, J. M.; Wignall, G. D.; Melnichenko, Y. B.; Frielinghaus, H; Berkowitz, M. L.

    2002-01-01

    The existence of microemulsions in the system composed of phosphate-based fluorosurfactant, water, and supercritical CO2 is demonstrated by small-angle neutron scattering experiments. A computer simulation study performed on a reverse micelle created in this system shows that the micelle remains stable over a 4 ns time period of the simulation. While the data obtained from the experiments provide information about the size of the reverse micelle, the data obtained from the simulations provide...

  12. How to Squeeze a Sponge: Casein Micelles under Osmotic Stress, a SAXS Study

    OpenAIRE

    Bouchoux, Antoine; Gésan-Guiziou, Geneviève; Pérez, Javier; Cabane, Bernard

    2010-01-01

    By combining the osmotic stress technique with small-angle x-ray scattering measurements, we followed the structural response of the casein micelle to an overall increase in concentration. When the aqueous phase that separates the micelles is extracted, they behave as polydisperse repelling spheres and their internal structure is not affected. When they are compressed, the micelles lose water and shrink to a smaller volume. Our results indicate that this compression is nonaffine, i.e., some p...

  13. Micelle swelling agent derived cavities for increasing hydrophobic organic compound removal efficiency by mesoporous micelle@silica hybrid materials

    KAUST Repository

    Shi, Yifeng

    2012-06-01

    Mesoporous micelle@silica hybrid materials with 2D hexagonal mesostructures were synthesized as reusable sorbents for hydrophobic organic compounds (HOCs) removal by a facile one-step aqueous solution synthesis using 3-(trimethoxysily)propyl-octadecyldimethyl-ammonium chloride (TPODAC) as a structure directing agent. The mesopores were generated by adding micelle swelling agent, 1,3,5-trimethyl benzene, during the synthesis and removing it afterward, which was demonstrated to greatly increase the HOC removal efficiency. In this material, TPODAC surfactant is directly anchored on the pore surface of mesoporous silica via SiOSi covalent bond after the synthesis due to its reactive Si(OCH 3) 3 head group, and thus makes the synthesized materials can be easily regenerated for reuse. The obtained materials show great potential in water treatment as pollutants sorbents. © 2011 Elsevier Inc. All rights reserved.

  14. Structure formation in binary mixtures of surfactants: vesicle opening-up to bicelles and octopus-like micelles

    Science.gov (United States)

    Noguchi, Hiroshi

    Micelle formation in binary mixtures of surfactants is studied using a coarse-grained molecular simulation. When a vesicle composed of lipid and detergent types of molecules is ruptured, a disk-shaped micelle, the bicelle, is typically formed. It is found that cup-shaped vesicles and bicelles connected with worm-like micelles are also formed depending on the surfactant ratio and critical micelle concentration. The obtained octopus shape of micelles agree with those observed in the cryo-TEM images reported in [S. Jain and F. S. Bates, Macromol. 37, 1511 (2004).]. Two types of connection structures between the worm-like micelles and the bicelles are revealed.

  15. Bioinspired, biomimetic, double-enzymatic mineralization of hydrogels for bone regeneration with calcium carbonate

    DEFF Research Database (Denmark)

    Lopez-Heredia, Marco A.; Łapa, Agata; Mendes, Ana Carina Loureiro

    2017-01-01

    Hydrogels are popular materials for tissue regeneration. Incorporation of biologically active substances, e.g. enzymes, is straightforward. Hydrogel mineralization is desirable for bone regeneration. Here, hydrogels of Gellan Gum (GG), a biocompatible polysaccharide, were mineralized biomimetical...

  16. Polymer micelles for delayed release of therapeutics from drug-releasing surfaces with nanotubular structures.

    Science.gov (United States)

    Sinn Aw, Moom; Addai-Mensah, Jonas; Losic, Dusan

    2012-08-01

    A new approach to engineer a local drug delivery system with delayed release using nanostructured surface with nanotube arrays is presented. TNT arrays electrochemically generated on a titanium surface are used as a model substrate. Polymer micelles as drug carriers encapsulated with drug are loaded at the bottom of the TNT structure and their delayed release is obtained by loading blank micelles (without drug) on the top. The delayed and time-controlled drug release is successfully demonstrated by controlling the ratio of blank and drug loaded-micelles. The concept is verified using four different polymer micelles (regular and inverted) loaded with water-insoluble (indomethacin) and water-soluble drugs (gentamicin).

  17. Rheological properties of novel viscoelastic micelle systems containing anionic-nonionic dimeric surfactant

    Institute of Scientific and Technical Information of China (English)

    方波; 曹丹红; 江体乾

    2008-01-01

    The viscoelastic micelle systems formed by novel anionic-nonionic dimeric surfactant and conventional cationic surfactant cetyltrimethylammonium(1631) were studied.The viscoelasticity,thixotropy,flow curves and constitutive equation for the novel viscoelastic micelle systems were investigated.The results show that the micelle systems possess viscoelasticity,thixotropy,and shear thinning property.Some micelle systems possess hysteresis loops showing both viscoelasticity and thixotropy.It is proved that the flow curves are characterized by the co-rotational Jeffreys constitutive equation correctly.

  18. ADVANCES IN MICROEMULSION PHASE ON SELF-ASSEMBLY AND MICELLE EXTRACTION WITH BLOCK COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    Chen Guo; Hao Wen; Huizhou Liu

    2005-01-01

    In this paper we review our work on self-assembly of the system, poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers, which is a kind of macromolecular complex fluids. The control of self-assembly could be obtained by adding inorganic salts or aliphatic alcohols. By self-assembly of amphiphilic block copolymers, a microemulsion phase is formed, which could be applied in micelle extraction, such as hollow-fiber membrane micelle extraction, magnetic micelle extraction and immobilized micelle extraction.

  19. Naturally derived micelles for rapid in vitro screening of potential cholesterol-lowering bioactives.

    Science.gov (United States)

    Kirana, Chandra; Rogers, Paul F; Bennett, Louise E; Abeywardena, Mahinda Y; Patten, Glen S

    2005-06-01

    A high plasma cholesterol level, especially low-density lipoprotein cholesterol, indicates increased risk of cardiovascular diseases. Plasma cholesterol levels are influenced by diet and cholesterol biosynthesis, uptake, and secretion. Cholesterol uptake involves solubilization into complex phospholipid spherical bodies termed micelles that facilitate the transport of lipids through the gut brush border membrane into enterocytes. In vitro assays reported to date to determine potential cholesterol-lowering effects of various compounds require artificial micelle preparations that are elaborate and time-consuming to prepare. The aims of this study were to compare the efficacy of artificially prepared micelles with naturally derived micelles from pig's bile and to test their ability to assess potential inhibitors of cholesterol uptake. The suitability of pig's bile-derived micelles was tested both at the level of the micelle and at cellular uptake using cultured Caco-2 cells. Known cholesterol uptake inhibitors at the micelle (green tea catechins) and at the Caco-2 cell (beta-lactoglobulin-derived peptide, IIAEK) were used as reference inhibitory compounds. It was concluded that pig's bile was a rapid, reproducible, convenient, and cost-effective source of micelles for cholesterol micelle solubility and cellular uptake assay systems and is suitable for screening purposes focused on identifying potential cholesterol-lowering agents.

  20. Kinetic analysis of hydrogen production using anaerobic bacteria in reverse micelles

    Energy Technology Data Exchange (ETDEWEB)

    Zhi, Xiaohua; Yang, Haijun; Yuan, Zhuliang; Shen, Jianquan [Beijing National Laboratory for Molecular Sciences (BNLMS), Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun North First Street 2, Beijing 100190 (China)

    2010-04-15

    The micellar formation and entrapment of bacteria cell in reverse micelles were investigated by ultraviolet spectrum (UV), fluorescence spectrum, and scanning electron microscope (SEM). The hydrogen production in reverse micelles was confirmed. The Gompertz equation was employed to evaluate the hydrogen-producing behavior in reverse micellar systems. Different systems including dioctyl sulfosuccinate sodium salt (AOT)-isooctane, sodium dodecyl sulfate (SDS)-benzene and SDS-carbon tetrachloride (CCl{sub 4}) reverse micelles were analysized. The results revealed that the maximum rate of hydrogen production (R{sub m}) was also suitable to formulate the relationship between hydrogen-producing rate and hydrogen productivity in reverse micelles. (author)

  1. Atomistic Simulation of Solubilization of Polycyclic Aromatic Hydrocarbons in a Sodium Dodecyl Sulfate Micelle.

    Science.gov (United States)

    Liang, Xujun; Marchi, Massimo; Guo, Chuling; Dang, Zhi; Abel, Stéphane

    2016-04-19

    Solubilization of two polycyclic aromatic hydrocarbons (PAHs), naphthalene (NAP, 2-benzene-ring PAH) and pyrene (PYR, 4-benzene-ring PAH), into a sodium dodecyl sulfate (SDS) micelle was studied through all-atom molecular dynamics (MD) simulations. We find that NAP as well as PYR could move between the micelle shell and core regions, contributing to their distribution in both regions of the micelle at any PAH concentration. Moreover, both NAP and PYR prefer to stay in the micelle shell region, which may arise from the greater volume of the micelle shell, the formation of hydrogen bonds between NAP and water, and the larger molecular volume of PYR. The PAHs are able to form occasional clusters (from dimer to octamer) inside the micelle during the simulation time depending on the PAH concentration in the solubilization systems. Furthermore, the micelle properties (i.e., size, shape, micelle internal structure, alkyl chain conformation and orientation, and micelle internal dynamics) are found to be nearly unaffected by the solubilized PAHs, which is irrespective of the properties and concentrations of PAHs.

  2. Preparation of bacterial cellulose based hydrogels and their viscoelastic behavior

    Science.gov (United States)

    Shah, Rushita; Vyroubal, Radek; Fei, Haojei; Saha, Nabanita; Kitano, Takeshi; Saha, Petr

    2015-04-01

    Bacterial cellulose (BC) based hydrogels have been prepared in blended with carboxymethylcellulose and polyvinyl pyrrolidone by using heat treatment. The properties of BC-CMC and BC-PVP hydrogels were compared with pure BC, CMC and PVP hydrogels. These hydrogels were investigated by measuring their structural, morphological and viscoelastic properties. Through the morphological images, alignment of the porous flake like structures could be seen clearly within the inter-polymeric network of the hydrogels. Also, the detail structure analysis of the polymers blended during the hydrogel formation confirms their interactions with each other were studied. Further, the viscoelastic behavior of all the hydrogels in terms of elastic and viscous property was studied. It is observed that at 1% strain, including CMC and PVP hydrogels, all the BC based hydrogels exhibited the linear trend throughout. Also the elastic nature of the material remains high compared to viscous nature. Moreover, the changes could be noticed in case of blended polymer based hydrogels. The values of complex viscosity (η*) decreases with increase in angular frequency within the range of ω = 0.1-100 rad.s-1.

  3. N-(furfural) chitosan hydrogels based on Diels-Alder cycloadditions and application as microspheres for controlled drug release.

    Science.gov (United States)

    Montiel-Herrera, Marcelino; Gandini, Alessandro; Goycoolea, Francisco M; Jacobsen, Neil E; Lizardi-Mendoza, Jaime; Recillas-Mota, Maricarmen; Argüelles-Monal, Waldo M

    2015-09-01

    In this study, chitosan was chemically modified by reductive amination in a two-step process. The synthesis of N-(furfural) chitosan (FC) was confirmed by FT-IR and (1)H NMR analysis, and the degrees of substitution were estimated as 8.3 and 23.8%. The cross-linkable system of bismaleimide (BM) and FC shows that FC shared properties of furan-maleimide chemistry. This system produced non-reversible hydrogel networks by Diels-Alder cycloadditions at 85 °C. The system composed of BM and FC (23.8% substitution) generated stronger hydrogel networks than those of FC with an 8.3% degree of substitution. Moreover, the FC-BM system was able to produce hydrogel microspheres. Environmental scanning electron microscopy revealed the surface of the microspheres to be non-porous with small protuberances. In water, the microspheres swelled, increasing their volume by 30%. Finally, microspheres loaded with methylene blue were able to release the dye gradually, obeying second-order kinetics for times less than 600 min. This behavior suggests that diffusion is governed by the relaxation of polymer chains in the swelled state, thus facilitating drug release outside the microspheres.

  4. Enhancement of Curcumin Bioavailability Using Nanocellulose Reinforced Chitosan Hydrogel

    Directory of Open Access Journals (Sweden)

    Thennakoon M. Sampath Udeni Gunathilake

    2017-02-01

    Full Text Available A unique biodegradable, superporous, swellable and pH sensitive nanocellulose reinforced chitosan hydrogel with dynamic mechanical properties was prepared for oral administration of curcumin. Curcumin, a less water-soluble drug was used due to the fact that the fast swellable, superporous hydrogel could release a water-insoluble drug to a great extent. CO2 gas foaming was used to fabricate hydrogel as it eradicates using organic solvents. Field emission scanning electron microscope images revealed that the pore size significantly increased with the formation of widely interconnected porous structure in gas foamed hydrogels. The maximum compression of pure chitosan hydrogel was 25.9 ± 1 kPa and it increased to 38.4 ± 1 kPa with the introduction of 0.5% cellulose nanocrystals. In vitro degradation of hydrogels was found dependent on the swelling ratio and the amount of CNC of the hydrogel. All the hydrogels showed maximum swelling ratios greater than 300%. The 0.5% CNC-chitosan hydrogel showed the highest swelling ratio of 438% ± 11%. FTIR spectrum indicated that there is no interaction between drug and ingredients present in hydrogels. The drug release occurred in non-Fickian (anomalous manner in simulated gastric medium. The drug release profiles of hydrogels are consistent with the data obtained from the swelling studies. After gas foaming of the hydrogel, the drug loading efficiency increased from 41% ± 2.4% to 50% ± 2.0% and release increased from 0.74 to 1.06 mg/L. The drug release data showed good fitting to Ritger-Peppas model. Moreover, the results revealed that the drug maintained its chemical activity after in vitro release. According to the results of this study, CNC reinforced chitosan hydrogel can be suggested to improve the bioavailability of curcumin for the absorption from stomach and upper intestinal tract.

  5. Doxorubicin-Loaded PEG-PCL-PEG Micelle Using Xenograft Model of Nude Mice: Effect of Multiple Administration of Micelle on the Suppression of Human Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Cuong, Nguyen-Van [Department of Biomedical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li, Taiwan (China); Department of Chemical Engineering, Ho Chi Minh City University of Industry, 12 Nguyen Van Bao St, Ho Chi Minh (Viet Nam); Jiang, Jian-Lin; Li, Yu-Lun [Department of Biomedical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li, Taiwan (China); Chen, Jim-Ray [Department of Pathology, Chang Gung Memorial Hospital at Keelung, Taiwan and Chang Gung University, College of Medicine, Taoyuan, Taiwan (China); Jwo, Shyh-Chuan [Division of General Surgery, Chang Gung Memorial Hospital at Keelung, Taiwan and Chang Gung University, College of Medicine, Taoyuan, Taiwan (China); Hsieh, Ming-Fa, E-mail: mfhsieh@cycu.edu.tw [Department of Biomedical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li, Taiwan (China)

    2010-12-28

    The triblock copolymer is composed of two identical hydrophilic segments Monomethoxy poly(ethylene glycol) (mPEG) and one hydrophobic segment poly(ε-caprolactone) (PCL); which is synthesized by coupling of mPEG-PCL-OH and mPEG-COOH in a mild condition using dicyclohexylcarbodiimide and 4-dimethylamino pyridine. The amphiphilic block copolymer can self-assemble into nanoscopic micelles to accommodate doxorubixin (DOX) in the hydrophobic core. The physicochemical properties and in vitro tests, including cytotoxicity of the micelles, have been characterized in our previous study. In this study, DOX was encapsulated into micelles with a drug loading content of 8.5%. Confocal microscopy indicated that DOX was internalized into the cytoplasm via endocystosis. A dose-finding scheme of the polymeric micelle (placebo) showed a safe dose of PEG-PCL-PEG micelles was 71.4 mg/kg in mice. Importantly, the circulation time of DOX-loaded micelles in the plasma significantly increased compared to that of free DOX in rats. A biodistribution study displayed that plasma extravasation of DOX in liver and spleen occurred in the first four hours. Lastly, the tumor growth of human breast cancer cells in nude mice was suppressed by multiple injections (5 mg/kg, three times daily on day 0, 7 and 14) of DOX-loaded micelles as compared to multiple administrations of free DOX.

  6. Doxorubicin-Loaded PEG-PCL-PEG Micelle Using Xenograft Model of Nude Mice: Effect of Multiple Administration of Micelle on the Suppression of Human Breast Cancer

    Directory of Open Access Journals (Sweden)

    Ming-Fa Hsieh

    2010-12-01

    Full Text Available The triblock copolymer is composed of two identical hydrophilic segments: Monomethoxy poly(ethylene glycol (mPEG and one hydrophobic segment poly(ε‑caprolactone (PCL; which is synthesized by coupling of mPEG-PCL-OH and mPEG‑COOH in a mild condition using dicyclohexylcarbodiimide and 4-dimethylamino pyridine. The amphiphilic block copolymer can self-assemble into nanoscopic micelles to accommodate doxorubixin (DOX in the hydrophobic core. The physicochemical properties and in vitro tests, including cytotoxicity of the micelles, have been characterized in our previous study. In this study, DOX was encapsulated into micelles with a drug loading content of 8.5%. Confocal microscopy indicated that DOX was internalized into the cytoplasm via endocystosis. A dose-finding scheme of the polymeric micelle (placebo showed a safe dose of PEG-PCL-PEG micelles was 71.4 mg/kg in mice. Importantly, the circulation time of DOX-loaded micelles in the plasma significantly increased compared to that of free DOX in rats. A biodistribution study displayed that plasma extravasation of DOX in liver and spleen occurred in the first four hours. Lastly, the tumor growth of human breast cancer cells in nude mice was suppressed by multiple injections (5 mg/kg, three times daily on day 0, 7 and 14 of DOX-loaded micelles as compared to multiple administrations of free DOX.

  7. Polyacrylamide Hydrogel Properties for Horticultural Applications

    Science.gov (United States)

    Polyacrylamide (PAAm) hydrogels are commonly employed to ensure hydration of the growth media and minimize crop losses during the crop production and postproduction phases in horticulture. However, studies of the effect of these materials have shown that they have a minimal effect on crop life and q...

  8. Polymer hydrogels as optimized delivery systems

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Jorge G.S.; Varca, Gustavo H.C.; Ferraz, Caroline C.; Garrido, Gabriela P.; Diniz, Bruna M.; Carvalho, Vinicius S.; Lugao, Ademar B., E-mail: jorgegabriel@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Hydrogels are formed by polymers capable of absorbing large quantities of water. They consist of one or more three-dimensionally structured polymer networks formed by macromolecular chains linked by covalent bonds-crosslinks - and physical interactions. The application of hydrogels, has been widely studied. Biodegradable synthetic or natural polymers such as chitosan, starch and poly-lactic-co-glycolic acid, have properties that allow the development of biodegradable systems for drug and nutraceutics delivery. This study aimed to develop polymeric hydrogels based on polyvinyl alcohol, polyacrylamide and polyvinylpyrrolidone using ionizing radiation in order to develop hydrogels for improved loading and release of compounds. Polymer solutions were solubilized in water and poured into thermoformed packages. After sealing, the material was subjected to γ-irradiation at 25kGy. The samples were assayed by means of mechanical properties, gel fraction and swelling degree. Nanostructure characterization was performed using Flory's equation to determine crosslinking density. The systems developed showed swelling degree and adequate mechanical resistance. The nanostructure evaluation showed different results for each system demonstrating the need of choosing the polymer based on the specific properties of each material. (author)

  9. Facile Use of Cationic Hydrogel Particles for Surface Modification of Planar Substrates Toward Multifunctional Neural Permissive Surfaces: An in Vitro Investigation.

    Science.gov (United States)

    Morin, Emily A; Tang, Shuangcheng; Rogers, Katie Lou; He, Wei

    2016-03-02

    Synthetic materials such as silicon have been commonly used for neural interfacing applications but are intrinsically noninteractive with neurons. Here, a facile approach has been developed to integrate both chemical and topographical cues to impart neural permissiveness for such materials. The approach simply exploits the basic phenomenon of electrostatically driven adsorption of colloidal particles onto a solid material and applies it to a cationic hydrogel particle system that we have developed recently based on "click" reaction of epoxide and amine. The particle adsorption process can be tuned by varying the adsorption time and the concentration of the original colloidal suspension, both of which directly control the surface densities of the adsorbed hydrogel particles. Using the PC12 cell line and primary cortical neurons derived from chick embryo, we demonstrate that the particle-adsorbed surface readily supports robust cell adhesion and differentiation. Although the extent of neural permissiveness exhibited by such particle-adsorbed surface was comparable to the cationic polyethylenimine-coated control surface, the adsorbed hydrogel particles offer a unique reservoir function to the modified surface that is unparalleled by the control. The successful loading of hydrophobic dye of nile red to the surface adsorbed hydrogel particles indicates that the modified surface not only provides physical support of neurons, but also can be explored in the future to exert localized therapeutic actions favorable for neural interfacing.

  10. Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yuanyuan; Xiang, Feng; Wang, Hong, E-mail: hwang@mail.xjtu.edu.cn, E-mail: suo@seas.harvard.edu [Electronic Materials Research Laboratory, School of Electronics and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, Baohong; Zhou, Jinxiong [State Key Laboratory for Strength and Vibration of Mechanical Structures, International Center for Applied Mechanics and School of Aerospace, Xi' an Jiaotong University, Xi' an 710049 (China); Suo, Zhigang, E-mail: hwang@mail.xjtu.edu.cn, E-mail: suo@seas.harvard.edu [School of Engineering and Applied Sciences, Kavli Institute of Bionano Science and Technology, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2014-10-13

    Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels become possible.

  11. Dye sensitized solar cells.

    Science.gov (United States)

    Wei, Di

    2010-03-16

    Dye sensitized solar cell (DSSC) is the only solar cell that can offer both the flexibility and transparency. Its efficiency is comparable to amorphous silicon solar cells but with a much lower cost. This review not only covers the fundamentals of DSSC but also the related cutting-edge research and its development for industrial applications. Most recent research topics on DSSC, for example, applications of nanostructured TiO(2), ZnO electrodes, ionic liquid electrolytes, carbon nanotubes, graphene and solid state DSSC have all been included and discussed.

  12. Dye Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Di Wei

    2010-03-01

    Full Text Available Dye sensitized solar cell (DSSC is the only solar cell that can offer both the flexibility and transparency. Its efficiency is comparable to amorphous silicon solar cells but with a much lower cost. This review not only covers the fundamentals of DSSC but also the related cutting-edge research and its development for industrial applications. Most recent research topics on DSSC, for example, applications of nanostructured TiO2, ZnO electrodes, ionic liquid electrolytes, carbon nanotubes, graphene and solid state DSSC have all been included and discussed.

  13. Development, Characterization, and Evaluation of PSMA-Targeted Glycol Chitosan Micelles for Prostate Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Jing Xu

    2014-01-01

    Full Text Available Prostate cancer-binding peptides- (PCP- modified polymeric micelles were prepared and used for the treatment of prostate-specific membrane antigen- (PSMA- expressing prostate cancer in a target-specific manner. Cholesterol-modified glycol chitosan (CHGC was synthesized. PCP-conjugated CHGC (PCP-CHGC micelles were fabricated and characterized. The degree of substitution was 5.2 PCP groups and 5.8 cholesterol groups per 100 sugar residues of glycol chitosan. The critical aggregation concentration (CAC of PCP-CHGC copolymer was 0.0254 mg/mL. Doxorubicin (DOX was chosen as a model antitumor drug. The DOX-loaded micelles were prepared by an o/w method. The mean diameter of DOX-loaded PCP-CHGC (DOX-PCP-CHGC micelles was 293 nm determined by dynamic light scattering (DLS. DOX released from drug-loaded micelles was in a biphasic manner. DOX-PCP-CHGC micelles exhibited higher cytotoxicity in vitro against PSMA-expressing LNCaP cells than DOX-loaded CHGC (DOX-CHGC micelles. Moreover, the cellular uptake of DOX-PCP-CHGC micelles determined by confocal laser scanning microscopy (CLSM and flow cytometry was higher than that of DOX-CHGC micelles in LNCaP cells. Importantly, DOX-PCP-CHGC micelles demonstrated stronger antitumor efficacy against LNCaP tumor xenograft models than doxorubicin hydrochloride and DOX-CHGC micelles. Taken together, this study provides a potential way in developing PSMA-targeted drug delivery system for prostate cancer therapy.

  14. Block copolymer micelles as nanocontainers for controlled release of proteins from biocompatible oil phases.

    Science.gov (United States)

    Miller, Andrew C; Bershteyn, Anna; Tan, Wuisiew; Hammond, Paula T; Cohen, Robert E; Irvine, Darrell J

    2009-04-13

    Biocompatible oils are used in a variety of medical applications ranging from vaccine adjuvants to vehicles for oral drug delivery. To enable such nonpolar organic phases to serve as reservoirs for delivery of hydrophilic compounds, we explored the ability of block copolymer micelles in organic solvents to sequester proteins for sustained release across an oil-water interface. Self-assembly of the block copolymer, poly(-caprolactone)-block-poly(2-vinyl pyridine) (PCL-b-P2VP), was investigated in toluene and oleic acid, a biocompatible naturally occurring fatty acid. Micelle formation in toluene was characterized by dynamic light scattering (DLS) and atomic force microscopy (AFM) imaging of micelles cast onto silicon substrates. Cryogenic transmission electron microscopy confirmed a spherical morphology in oleic acid. Studies of homopolymer solubility implied that micelles in oleic acid consist of a P2VP corona and a PCL core, while P2VP formed the core of micelles assembled in toluene. The loading of two model proteins (ovalbumin (ova) and bovine serum albumin (BSA)) into micelles was demonstrated with loadings as high as 7.8% wt of protein per wt of P2VP in oleic acid. Characterization of block copolymer morphology in the two solvents after protein loading revealed spherical particles with similar size distributions to the as-assembled micelles. Release of ova from micelles in oleic acid was sustained for 12-30 h upon placing the oil phase in contact with an aqueous bath. Unique to the situation of micelle assembly in an oily phase, the data suggest protein is sequestered in the P2VP corona block of PCL-b-P2VP micelles in oleic acid. More conventionally, protein loading occurs in the P2VP core of micelles assembled in toluene.

  15. Versatile Molding Process for Tough Cellulose Hydrogel Materials.

    Science.gov (United States)

    Kimura, Mutsumi; Shinohara, Yoshie; Takizawa, Junko; Ren, Sixiao; Sagisaka, Kento; Lin, Yudeng; Hattori, Yoshiyuki; Hinestroza, Juan P

    2015-11-05

    Shape-persistent and tough cellulose hydrogels were fabricated by a stepwise solvent exchange from a homogeneous ionic liquid solution of cellulose exposure to methanol vapor. The cellulose hydrogels maintain their shapes under changing temperature, pH, and solvents. The micrometer-scale patterns on the mold were precisely transferred onto the surface of cellulose hydrogels. We also succeeded in the spinning of cellulose hydrogel fibers through a dry jet-wet spinning process. The mechanical property of regenerated cellulose fibers improved by the drawing of cellulose hydrogel fibers during the spinning process. This approach for the fabrication of tough cellulose hydrogels is a major advance in the fabrication of cellulose-based structures with defined shapes.

  16. Antimicrobial Activity of Chitosan-Carbon Nanotube Hydrogels

    Directory of Open Access Journals (Sweden)

    Jayachandran Venkatesan

    2014-05-01

    Full Text Available In the present study, we have prepared chitosan-carbon nanotube (Chitosan-CNT hydrogels by the freeze-lyophilization method and examined their antimicrobial activity. Different concentrations of CNT were used in the preparation of Chitosan-CNT hydrogels. These differently concentrated CNT hydrogels were chemically characterized using Fourier Transform-Infrared Spectroscopy, Scanning Electron Microscopy and Optical microscopy. The porosity of the hydrogels were found to be >94%. Dispersion of chitosan was observed in the CNT matrix by normal photography and optical microscopy. The addition of CNT in the composite scaffold significantly reduced the water uptake ability. In order to evaluate antimicrobial activity, the serial dilution method was used towards Staphylococcus aureus, Escherichia coli and Candida tropicalis. The composite Chitosan-CNT hydrogel showed greater antimicrobial activity with increasing CNT concentration, suggesting that Chitosan-CNT hydrogel scaffold will be a promising biomaterial in biomedical applications.

  17. Comparison of Pectin Hydrogel Collection Methods in Microfluidic Device

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chaeyeon; Park, Ki-Su; Kang, Sung-Min; Kim, Jongmin; Song, YoungShin; Lee, Chang-Soo [Chungnam National University, Daejeon (Korea, Republic of)

    2015-12-15

    This study investigated the effect of different collection methods on physical properties of pectin hydrogels in microfluidic synthetic approach. The pectin hydrogels were simply produced by the incorporation of calcium ions dissolved in continuous mineral oil. Then, different collection methods, pipetting, tubing, and settling, for harvesting pectin hydrogels were applied. The settling method showed most uniform and monodispersed hydrogels. In the case of settling, a coefficient of variation was 3.46 which was lower than pipetting method (18.60) and tubing method (14.76). Under the settling method, we could control the size of hydrogels, ranging from 30 μm to 180 μm, by simple manipulation of the viscosity of pectin and volumetric flow rate of dispersed and continuous phase. Finally, according to the characteristics of simple encapsulation of biological materials, we envision that the pectin hydrogels can be applied to drug delivery, food, and biocompatible materials.

  18. ADDITIVE-INDUCED ENHANCEMENT OF OPTICAL CLARITY OF POLYACRYLAMIDE HYDROGEL

    Institute of Scientific and Technical Information of China (English)

    Jeffery Franklin; Zhi Yuan Wang

    2003-01-01

    The aqueous polymerization of acrylamide and crosslinking with N,N-methylenebisacrylamide afforded hydrogels displaying high levels of light scattering (poor optical clarity). Enhancement of the optical clarity within a polyacrylamide (PAm) hydrogel was accomplished through the implementation of"refractive index matching", Water-soluble additives were utilised to better match the refractive index inhomogeneities throughout a given hydrogel. This resulted in lower light scattering within the system and hence improved clarity. Amino acids, sugars, polymers, and other water-soluble additives such as glycerol were investigated by this methodology. Most additives investigated displayed potential for effectively reducing the light scattering within a PAm hydrogel as a function of increased additive concentration. On increasing the refractive index of the water medium, the overall refractive index of a PAm hydrogel was also observed to increase. This provided a quantitative means of determining the effectiveness of a given additive for improving the optical clarity within a hydrogel.

  19. Swelling Behaviors of Polyaniline-Poly(Acrylic Acid) Hydrogels

    Institute of Scientific and Technical Information of China (English)

    ZHANG You-wei; ZHAO Jiong-xin; LI Xiao-feng; TAO Yong; WU Cheng-xun

    2005-01-01

    Using poly(acrylic acid) (PAA) aqueous solution, NaOH aqueous solution, aniline(An) and ammonim persulfate(APS), PAn-PAA hydrogels with a semi-interpenetrating structure connected by physical interlocks, chemical ion bonds and hydrogen bonds wcre prepared. The swelling properties of the hydrogels in solutions of different pH values(adjusted by adding NaOH or HCl) were studied. All the hydrogels prepared have similar swelling curves (the curves of equilibrium swelling ratio vs. pH value) and reach their maximum swelling at pH of 8 - 10. The maximum swelling ratio of the hydrogels is dependent on composition, including molecular weight of PAA, polymer content of the hydrogel,and molar ratios of AA to An, APS to An, and NaOH to AA.And the compositional dependence of the swelling capacity of PAn-PAA hydrogels was also studied.

  20. Stimuli-responsive hydrogels in drug delivery and tissue engineering.

    Science.gov (United States)

    Sood, Nikhil; Bhardwaj, Ankur; Mehta, Shuchi; Mehta, Abhinav

    2016-01-01

    Hydrogels are the three-dimensional network structures obtained from a class of synthetic or natural polymers which can absorb and retain a significant amount of water. Hydrogels are one of the most studied classes of polymer-based controlled drug release. These have attracted considerable attention in biochemical and biomedical fields because of their characteristics, such as swelling in aqueous medium, biocompatibility, pH and temperature sensitivity or sensitivity towards other stimuli, which can be utilized for their controlled zero-order release. The hydrogels are expected to explore new generation of self-regulated delivery system having a wide array of desirable properties. This review highlights the exciting opportunities and challenges in the area of hydrogels. Here, we review different literatures on stimuli-sensitive hydrogels, such as role of temperature, electric potential, pH and ionic strength to control the release of drug from hydrogels.

  1. Dielectric properties of Rhodamine-B and metal doped hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Okutan, M. [Department of Physics, Yıldız Technical University, 34210 Istanbul (Turkey); Coşkun, R. [Department of Chemistry, Bozok University, 66100 Yozgat (Turkey); Öztürk, M. [Institute of Science, Niğde University, 51240 Niğde (Turkey); Yalçın, O., E-mail: o.yalcin@nigde.edu.tr [Department of Physics, Niğde University, 51240 Niğde (Turkey)

    2015-01-15

    The electric and dielectric properties of Rhodamine-B (RB) and metal ions (Ag{sup +}, Co{sup 2+}, Cr{sup 3+}, Mn{sup 2+} and Ni{sup 2+}) doped hydrogels have been analyzed in an extended frequency range by impedance spectroscopy. The RB doped hydrogels has been found to be sensitive to ionic conduction and electrode polarization according to the metal doped hydrogels. We have shown that the ionic conductive of RB doped hydrogels is originated from the free ions motion within the doped hydrogels at high frequency. We have also taken into account the Cl{sup −} and N{sup +} ions in the structure of RB provide additional ionic contribution to RB doped hydrogels.

  2. Mechanical Behavior of Tough Hydrogels for Structural Applications

    Science.gov (United States)

    Illeperuma, Widusha Ruwangi Kaushalya

    Hydrogels are widely used in many commercial products including Jell-O, contact lenses, and superabsorbent diapers. In recent decades, hydrogels have been under intense development for biomedical applications, such as scaffolds in tissue engineering, carriers for drug delivery, and valves in microfluidic systems. But the scope is severely limited as conventional hydrogels are weak and brittle and are not very stretchable. This thesis investigates the approaches that enhance the mechanical properties of hydrogels and their structural applications. We discov¬ered a class of exceptionally stretchable and tough hydrogels made from poly-mers that form networks via ionic and covalent crosslinks. Although such a hydrogel contains ~90% water, it can be stretched beyond 20 times its initial length, and has a fracture energy of ~9000 J/m2. The combination of large stretchability, remarkable toughness, and recoverability of stiffness and toughness, along with easy synthesis makes this material much superior over existing hydrogels. Extreme stretchability and blunted crack tips of these hydrogels question the validity of traditional fracture testing methods. We re-examine a widely used pure shear test method to measure the fracture energy. With the experimental and simulation results, we conclude that the pure shear test method can be used to measure fracture energy of extremely stretchable materials. Even though polyacrylamide-alginate hydrogels have an extremely high toughness, it has a relatively low stiffness and strength. We improved the stiffness and strength by embedding fibers. Most hydrogels are brittle, allowing the fibers to cut through the hydrogel when the composite is loaded. But tough hydrogel composites do not fail by the fibers cutting the hydrogel; instead, it undergoes large deforming by fibers sliding through the matrix. Hydrogels were not considered as materials for structural applications. But with enhanced mechanical properties, they have opened up

  3. Carcinogenicity of hair dye components.

    Science.gov (United States)

    Van Duuren, B L

    1980-03-01

    The available animal carcinogenicity data on hair dye components was reviewed. From this review it became clear that certain hair dye components, some of which are still in hair dye formulations now on the market, are animal carcinogens. The compounds of concern that are still in use are: 3-amino-4-methoxyaniline, 2-nitro-4-aminoaniline and 3-nitro-4-hydroxyaniline. Certain azo dyes formerly used, and related compounds still in use, contain the benzidine moiety. Two of these compounds, Direct Blue 6 and Direct Black 38, have been shown to be metabolized in animals to the human carcinogen benzidine. Furthermore, skin absorption studies carried out with radiolabeled hair dye components applied to animal or human skin have conclusively shown that these compounds are systemically absorbed and excreted. Known cocarcinogens such as catechol and pyrogallol, which enhance benzo(a)pyrene carcinogenicity on mouse skin, are used as hair dye components. It is not known whether such compounds will enhance the carcinogenicity of substituted aniline hair dye chemicals. The available epidemiologic data are not sufficient to link hair dye use with an increased incidence in human cancer.

  4. Photochemical Patterning of Ionically Cross-Linked Hydrogels

    Directory of Open Access Journals (Sweden)

    Marion Bruchet

    2013-08-01

    Full Text Available Iron(III cross-linked alginate hydrogel incorporating sodium lactate undergoes photoinduced degradation, thus serving as a biocompatible positive photoresist suitable for photochemical patterning. Alternatively, surface etching of iron(III cross-linked hydrogel contacting lactic acid solution can be used for controlling the thickness of the photochemical pattering. Due to biocompatibility, both of these approaches appear potentially useful for advanced manipulation with cell cultures including growing cells on the surface or entrapping them within the hydrogel.

  5. 4D Printing with Mechanically Robust, Thermally Actuating Hydrogels.

    Science.gov (United States)

    Bakarich, Shannon E; Gorkin, Robert; in het Panhuis, Marc; Spinks, Geoffrey M

    2015-06-01

    A smart valve is created by 4D printing of hydrogels that are both mechanically robust and thermally actuating. The printed hydrogels are made up of an interpenetrating network of alginate and poly(N-isopropylacrylamide). 4D structures are created by printing the "dynamic" hydrogel ink alongside other static materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Interaction of fluorescence dyes with 5-fluorouracil: A photoinduced electron transfer study in bulk and biologically relevant water

    Science.gov (United States)

    Kuchlyan, Jagannath; Banik, Debasis; Kundu, Niloy; Roy, Arpita; Sarkar, Nilmoni

    2014-10-01

    The interactions of widely used chemotherapeutic drug, 5-fluorouracil (5FU) with coumarin dyes have been investigated for the first time using steady-state and time-resolved fluorescence spectroscopic measurements. The fluorescence quenching along with the decrease in lifetimes of excited state of coumarin derivatives with gradual addition of 5FU is explained by photoinduced electron transfer (PET) mechanism. Our studies were performed in bulk water and confined water of AOT (aerosol OT) reverse micelle to investigate the effect of confinement on PET dynamics. The feasibility of PET reaction for coumarin-5FU systems is investigated calculating the standard free energy changes using the Rehm-Weller equation.

  7. Responsive Hydrogels for Label-Free Signal Transduction within Biosensors

    Directory of Open Access Journals (Sweden)

    Kamila Gawel

    2010-04-01

    Full Text Available Hydrogels have found wide application in biosensors due to their versatile nature. This family of materials is applied in biosensing either to increase the loading capacity compared to two-dimensional surfaces, or to support biospecific hydrogel swelling occurring subsequent to specific recognition of an analyte. This review focuses on various principles underpinning the design of biospecific hydrogels acting through various molecular mechanisms in transducing the recognition event of label-free analytes. Towards this end, we describe several promising hydrogel systems that when combined with the appropriate readout platform and quantitative approach could lead to future real-life applications.

  8. Tough and tunable adhesion of hydrogels: experiments and models

    Science.gov (United States)

    Zhang, Teng; Yuk, Hyunwoo; Lin, Shaoting; Parada, German A.; Zhao, Xuanhe

    2017-06-01

    As polymer networks infiltrated with water, hydrogels are major constituents of animal and plant bodies and have diverse engineering applications. While natural hydrogels can robustly adhere to other biological materials, such as bonding of tendons and cartilage on bones and adhesive plaques of mussels, it is challenging to achieve such tough adhesions between synthetic hydrogels and engineering materials. Recent experiments show that chemically anchoring long-chain polymer networks of tough synthetic hydrogels on solid surfaces create adhesions tougher than their natural counterparts, but the underlying mechanism has not been well understood. It is also challenging to tune systematically the adhesion of hydrogels on solids. Here, we provide a quantitative understanding of the mechanism for tough adhesions of hydrogels on solid materials via a combination of experiments, theory, and numerical simulations. Using a coupled cohesive-zone and Mullins-effect model validated by experiments, we reveal the interplays of intrinsic work of adhesion, interfacial strength, and energy dissipation in bulk hydrogels in order to achieve tough adhesions. We further show that hydrogel adhesion can be systematically tuned by tailoring the hydrogel geometry and silanization time of solid substrates, corresponding to the control of energy dissipation zone and intrinsic work of adhesion, respectively. The current work further provides a theoretical foundation for rational design of future biocompatible and underwater adhesives.

  9. PVA/atapulgite hydrogels; Hidrogeis de PVA/atapulgita

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, R.N.; Soares, G.A., E-mail: nunes@metalmat.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Paranhos, C.M. [Universidade Federal de Sao Carlos (UFSCAR), SP (Brazil); Barreto, L.S. [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil)

    2010-07-01

    PVA hydrogels can be used as wound-healing as a consequence of their biocompatibility, flexibility, etc. In order to improve mechanical resistance of wound-healing, polymeric hydrogels reinforced with clay have been studied. Among national clays, attapulgite stands out. Once it is a natural material, acid treatment can be required in order to remove impurities. In the present work, PVA hydrogels reinforced with attapulgite were produced and they were characterized by swelling behavior, XRD, DSC and traction test. Among all properties studied, hydrogels reinforced with activated attapulgite showed better mechanical resistance and Young module than the other samples. (author)

  10. Injectable Biopolymer-hydroxyapatite Hydrogels: Obtaining and their Characterization

    Directory of Open Access Journals (Sweden)

    L.B. Sukhodub

    2016-03-01

    Full Text Available Hydrogels based on hydroxyapatite (HA and Chitosan (CS with addition of sodium alginate (Alg were synthesized by in situ precipitation method. Structure, morphology, chemical and phase composition of the HA/CS and HA/CS/Alg hydrogels were characterized by TEM, FTIR and XRD. Hydrogels consist of low crystallinity calcium deficient hydroxyapatite (JCPDS 9 432, the needle-like crystallites have an average size 25 nm. The introduction of Alginate powder into HA/CS hydrogel solution demonstrate the viscosity enhancing of the HA/CS hydrogel due to polyelectrolyte reaction between Alginate and Chitosan macromolecules. Two natural polymers and partially released from hydroxyapatite Ca2+ ions formed a matrix by crosslinking the polymer macromolecules through hydroxyl, amino and carbonyl groups. These processes promote the formation of a more stable structure of HA/CS/Alg hydrogel as compared to HA/CS. The structural integrity and degradation tests have demonstrated that HA/CS/Alg1.0 saved its initial shape in 7 days of shaking in SBF solution, meanwhile for HA/CS, a structural decay was observed. The HA/CS hydrogel had completely lost its volume support after 1 day shaking in SBF. Thus, the ability of HA/CS hydrogel to maintain its shape with implantation into bone tissue defect may be enhanced with alginate addition, but alginate content more than 1 w/w % reduces the hydrogel plasticity, increases the swelling and accelerates the shape decay.

  11. Thermo-Responsive Hydrogels for Stimuli-Responsive Membranes

    Directory of Open Access Journals (Sweden)

    Evan Mah

    2013-09-01

    Full Text Available Composite membranes with stimuli-responsive properties can be made by coating a thermo-responsive hydrogel onto a micro- or macroporous support. These hydrogels undergo a temperature induced volume-phase transition, which contributes towards the composite membrane’s stimuli-responsive properties. This paper reviews research done on complimentary forms of temperature responsive “thermophilic” hydrogels, those exhibiting positive volume-phase transitions in aqueous solvent. The influences of intermolecular forces on the mechanism of phase-transition are discussed along with case examples of typical thermophilic hydrogels.

  12. Biodegradable HEMA-based hydrogels with enhanced mechanical properties.

    Science.gov (United States)

    Moghadam, Mohamadreza Nassajian; Pioletti, Dominique P

    2016-08-01

    Hydrogels are widely used in the biomedical field. Their main purposes are either to deliver biological active agents or to temporarily fill a defect until they degrade and are followed by new host tissue formation. However, for this latter application, biodegradable hydrogels are usually not capable to sustain any significant load. The development of biodegradable hydrogels presenting load-bearing capabilities would open new possibilities to utilize this class of material in the biomedical field. In this work, an original formulation of biodegradable photo-crosslinked hydrogels based on hydroxyethyl methacrylate (HEMA) is presented. The hydrogels consist of short-length poly(2-hydroxyethyl methacrylate) (PHEMA) chains in a star shape structure, obtained by introducing a tetra-functional chain transfer agent in the backbone of the hydrogels. They are cross-linked with a biodegradable N,O-dimethacryloyl hydroxylamine (DMHA) molecule sensitive to hydrolytic cleavage. We characterized the degradation properties of these hydrogels submitted to mechanical loadings. We showed that the developed hydrogels undergo long-term degradation and specially meet the two essential requirements of a biodegradable hydrogel suitable for load bearing applications: enhanced mechanical properties and low molecular weight degradation products. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1161-1169, 2016.

  13. Force-compensated hydrogel-based pH sensor

    Science.gov (United States)

    Deng, Kangfa; Gerlach, Gerald; Guenther, Margarita

    2015-04-01

    This paper presents the design, simulation, assembly and testing of a force-compensated hydrogel-based pH sensor. In the conventional deflection method, a piezoresistive pressure sensor is used as a chemical-mechanical-electronic transducer to measure the volume change of a pH-sensitive hydrogel. In this compensation method, the pH-sensitive hydrogel keeps its volume constant during the whole measuring process, independent of applied pH value. In order to maintain a balanced state, an additional thermal actuator is integrated into the close-loop sensor system with higher precision and faster dynamic response. Poly (N-isopropylacrylamide) (PNIPAAm) with 5 mol% monomer 3-acrylamido propionic acid (AAmPA) is used as the temperature-sensitive hydrogel, while poly (vinyl alcohol) with poly (acrylic acid) (PAA) serves as the pH-sensitive hydrogel. A thermal simulation is introduced to assess the temperature distribution of the whole microsystem, especially the temperature influence on both hydrogels. Following tests are detailed to verify the working functions of a sensor based on pH-sensitive hydrogel and an actuator based on temperature-sensitive hydrogel. A miniaturized prototype is assembled and investigated in deionized water: the response time amounts to about 25 min, just half of that one of a sensor based on the conventional deflection method. The results confirm the applicability of t he compensation method to the hydrogel-based sensors.

  14. Physically crosslinked-sacran hydrogel films for wound dressing application.

    Science.gov (United States)

    Wathoni, Nasrul; Motoyama, Keiichi; Higashi, Taishi; Okajima, Maiko; Kaneko, Tatsuo; Arima, Hidetoshi

    2016-08-01

    The thin hydrogel films consisting of water-swollen polymer networks can potentially be applied for biomedical fields. Recently, natural polysaccharides have great attentions to be developed as wound healing and protection. In the present study, we newly prepared and characterized a physically crosslinked-hydrogel film composed of a novel megamolecular polysaccharide sacran for wound dressing application. We successfully fabricated a physically crosslinked-sacran hydrogel film by a solvent-casting method. The thickness of a sacran hydrogel film was lower than that of a sodium alginate (Na-alginate) film. Importantly, the swollen ratio of a sacran hydrogel film in water at 24h was 19-fold, compared to initial weight. Meanwhile, a Na-alginate hydrogel film was completely broken apart after rehydration. Moreover, a sacran hydrogel film did not show any cytotoxicity on NIH3T3 cells, a murine fibroblast cell line. The in vivo skin hydration study revealed that a sacran hydrogel film significantly increased the moisture content on hairless mice skin and considerably improved wound healing ability, compared to control (non-treated), probably due to not only the moisturing effect but also the anti-inflammatory effect of sacran. These results suggest that sacran has the potential properties as a basic biomaterial in a hydrogel film for wound dressing application.

  15. Bragg grating chemical sensor with hydrogel as sensitive element

    Institute of Scientific and Technical Information of China (English)

    Xiaomei Liu(刘小梅); Shilie Zheng(郑史烈); Xianmin Zhang(章献民); Jun Cong(丛军); Kangsheng Chen(陈抗生); Jian Xu(徐坚)

    2004-01-01

    A novel fiber Bragg grating (FBG) based chemical sensor using hydrogel, a swellable polymer, as sensitive element is demonstrated. The sensing mechanism relies on the shift of Bragg wavelength due to the stress resulted from volume change of sensitive swellable hydrogel responding to the change of external environment. A polyacrylamide hydrogel fiber grating chemical sensor is made, and the experiments on its sensitivity to the salinity are performed. The sensitivity is low due to the less stress from the shrinking or swelling of hydrogels. Reducing the cross diameter of the grating through etching with hydrofluoric acid can greatly improve the sensitivity of the sensor.

  16. Tumor Growth Suppression Induced by Biomimetic Silk Fibroin Hydrogels

    Science.gov (United States)

    Yan, Le-Ping; Silva-Correia, Joana; Ribeiro, Viviana P.; Miranda-Gonçalves, Vera; Correia, Cristina; da Silva Morais, Alain; Sousa, Rui A.; Reis, Rui M.; Oliveira, Ana L.; Oliveira, Joaquim M.; Reis, Rui L.

    2016-08-01

    Protein-based hydrogels with distinct conformations which enable encapsulation or differentiation of cells are of great interest in 3D cancer research models. Conformational changes may cause macroscopic shifts in the hydrogels, allowing for its use as biosensors and drug carriers. In depth knowledge on how 3D conformational changes in proteins may affect cell fate and tumor formation is required. Thus, this study reports an enzymatically crosslinked silk fibroin (SF) hydrogel system that can undergo intrinsic conformation changes from random coil to β-sheet conformation. In random coil status, the SF hydrogels are transparent, elastic, and present ionic strength and pH stimuli-responses. The random coil hydrogels become β-sheet conformation after 10 days in vitro incubation and 14 days in vivo subcutaneous implantation in rat. When encapsulated with ATDC-5 cells, the random coil SF hydrogel promotes cell survival up to 7 days, whereas the subsequent β-sheet transition induces cell apoptosis in vitro. HeLa cells are further incorporated in SF hydrogels and the constructs are investigated in vitro and in an in vivo chick chorioallantoic membrane model for tumor formation. In vivo, Angiogenesis and tumor formation are suppressed in SF hydrogels. Therefore, these hydrogels provide new insights for cancer research and uses of biomaterials.

  17. Unimolecular micelles and electrostatic nanoassemblies stemming from hyperbranched polyethyleneimine

    Energy Technology Data Exchange (ETDEWEB)

    Picco, A.; Azzaroni, O.; Ceolin, M. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplic, La Plata, BA (Argentina); Silbestri, G.F. [Universidad Nacional del Sur, Bahia Blanca Bueno (Argentina)

    2012-07-01

    Full text: Hyperbranched polyethyleneimine (HPEI) was used as a building block to construct different self-assembled soft nanomaterials. This was accomplished via covalent linkage of carboxylic acids (CA) of different chain lengths to terminal amino groups of HPEI, thus leading to the formation of reverse unimolecular micelles constituted of a hydrophilic core and a hydrophobic shell. On the other hand, acid base interactions in organic solvents between CAs and peripheral amino groups of HPEI also facilitated the formation of electrostatic assemblies with reverse micellar properties. In this work we describe the formation of both structures as well as their characterization using diverse techniques including SAXS, NMR, IR, and fluorescence spectroscopy, among others. Unimolecular micelles were synthesized through the reaction of HPEI (Mn= 10 KDa) and acyl chlorides with different chain lengths (C8, C10, C12, C14, C16, C18). Depending on the chain length, the solvent and the temperature, a broad variety of supra macromolecular assemblies can be observed by SAXS measurements, including structured aggregation, and gelation. Hyperbranched electrostatic assemblies were simply produced by mixing HPEI with selected carboxylic acids (C8, C10, C12, C14, C16, C18) in an appropriate solvent, which dissolves the CA, or both reactants, i.e. chloroform, toluene or THF. The formation of the assemblies was corroborated using FT-IR by monitoring the appearance of the carboxylate bands. SAXS experiments of electrostatically assembled micelles showed globular, core-shell structures, whose characteristics are similar, in many cases, to their covalent counterparts prepared using the same chain length CA shells. (author)

  18. Preparation and evaluation of novel mixed micelles as nanocarriers for intravenous delivery of propofol

    Science.gov (United States)

    Li, Xinru; Zhang, Yanhui; Fan, Yating; Zhou, Yanxia; Wang, Xiaoning; Fan, Chao; Liu, Yan; Zhang, Qiang

    2011-12-01

    Novel mixed polymeric micelles formed from biocompatible polymers, poly(ethylene glycol)-poly(lactide) (mPEG-PLA) and polyoxyethylene-660-12-hydroxy stearate (Solutol HS15), were fabricated and used as a nanocarrier for solubilizing poorly soluble anesthetic drug propofol. The solubilization of propofol by the mixed micelles was more efficient than those made of mPEG-PLA alone. Micelles with the optimized composition of mPEG-PLA/Solutol HS15/propofol = 10/1/5 by weight had particle size of about 101 nm with narrow distribution (polydispersity index of about 0.12). Stability analysis of the mixed micelles in bovine serum albumin (BSA) solution indicated that the diblock copolymer mPEG efficiently protected the BSA adsorption on the mixed micelles because the hydrophobic groups of the copolymer were efficiently screened by mPEG, and propofol-loaded mixed micelles were stable upon storage for at least 6 months. The content of free propofol in the aqueous phase for mixed micelles was lower by 74% than that for the commercial lipid emulsion. No significant differences in times to unconsciousness and recovery of righting reflex were observed between mixed micelles and commercial lipid formulation. The pharmacological effect may serve as pharmaceutical nanocarriers with improved solubilization capacity for poorly soluble drugs.

  19. Pharmacokinetics and biodistribution of polymeric micelles of paclitaxel with Pluronic P123

    Institute of Scientific and Technical Information of China (English)

    Li-mei HAN; Lie GUO; Li-jun ZHANG; Qing-song WANG; Xiao-ling FANG

    2006-01-01

    Aim: To investigate the preparation, in vitro release, in vivo pharmacokinetics and tissue distribution of a novel polymeric micellar formulation of paclitaxel (PTX) with Pluronic P123. Methods: The polymeric micelles of paclitaxel with Pluronic PI23 were prepared by a solid dispersion method. The characteristics of micelles including particle size distribution, morphology and in vitro release of PTX from micelles were carried out. PTX-loaded micellar solutions were administered through the tail vein to healthy Sprague-Dawley rats and Kunming strain mice to assess the pharmacokinetics and tissue distribution of PTX, respectively. Taxol, the commercially available intravenous formulation of PTX, was also administered as control. Results: By using a dynamic light scattering sizer and a transmission electron microscopy, it was shown that the PTX-loaded micelles had a mean size of approximately 25 nm with narrow size distribution and a spherical shape. PTX was continuously released from Pluronic PI23 micelles in release medium containing 1 mol/L sodium salicylate for 24 h at 37℃. In the pharmacokinetic assessment, t1/2β and AUC of micelle formulation were 2.3 and 2.9-fold higher than that of Taxol injection. And the PTX-loaded micelles increased the uptake of PTX in the plasma, ovary and uterus, lung, and kidney, but decreased uptake in the liver and brain in the biodistribution study. Conclusion: Polymeric micelles using Pluronic P123 can effectively solubilize PTX, prolong blood circulation time and modify the biodistribution of PTX.

  20. Peptide-conjugated micelles as a targeting nanocarrier for gene delivery

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Wen Jen, E-mail: wjlin@ntu.edu.tw; Chien, Wei Hsuan [National Taiwan University, School of Pharmacy, Graduate Institute of Pharmaceutical Sciences (China)

    2015-09-15

    The aim of this study was to develop peptide-conjugated micelles possessing epidermal growth factor receptor (EGFR) targeting ability for gene delivery. A sequence-modified dodecylpeptide, GE11(2R), with enhancing EGF receptor binding affinity, was applied in this study as a targeting ligand. The active targeting micelles were composed of poly(d,l-lactide-co-glycolide)-poly(ethylene glycol) (PLGA-PEG) copolymer conjugated with GE11(2R)-peptide. The particle sizes of peptide-free and peptide-conjugated micelles were 277.0 ± 5.1 and 308.7 ± 14.5 nm, respectively. The peptide-conjugated micelles demonstrated the cellular uptake significantly higher than peptide-free micelles in EGFR high-expressed MDA-MB-231 and MDA-MB-468 cells due to GE11(2R)-peptide specificity. Furthermore, the peptide-conjugated micelles were able to encapsulate plasmid DNA and expressed cellular transfection higher than peptide-free micelles in EGFR high-expressed cells. The EGFR-targeting delivery micelles enhanced DNA internalized into cells and achieved higher cellular transfection in EGFR high-expressed cells.

  1. Tuneable & degradable polymeric micelles for drug delivery: from synthesis to feasibility in vivo

    NARCIS (Netherlands)

    Rijcken, C.J.F.

    2007-01-01

    In recent years, colloidal systems (e.g. liposomes, nanoparticles and micelles) are increasingly applied as vehicles for controlled drug delivery purposes. Ideally, the encapsulation of hydrophobic drugs in a micellar core prolongs the systemic circulation and drug-loaded micelles selectively accumu

  2. Effect of Spacers on CMCs and Micelle-forming Enthalpies of Gemini Surfactants by Titration Microcalorimetry

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The critical micelle concentrations (CMC) and the micelle-forming enthalpies (D Hmic) of gemini surfactants were first measured by the precise titration microcalorimetry. The results showed that D Hmic values are negative, and there is an exothermal minimum between s=4 and s=6. Furthermore, the CMCs of the surfactants are in good agreement with literature values.

  3. Comprehensive theory for star-like polymer micelles: combining classical nucleation and polymer brush theory

    NARCIS (Netherlands)

    Sprakel, J.H.B.; Leermakers, F.A.M.; Cohen Stuart, M.A.; Besseling, N.A.M.

    2008-01-01

    A comprehensive theory is proposed that combines classical nucleation and polymer brush theory to describe star-like polymer micelles. With a minimum of adjustable parameters, the model predicts properties such as critical micelle concentrations and micellar size distributions. The validity of the p

  4. Histological study on side effects and tumor targeting of a block copolymer micelle on rats.

    Science.gov (United States)

    Kawaguchi, Takanori; Honda, Takashi; Nishihara, Masamichi; Yamamoto, Tatsuhiro; Yokoyama, Masayuki

    2009-06-19

    Histological examinations were performed with polymeric micelle-injected rats for evaluations of possible toxicities of polymeric micelle carriers. Weight of major organs as well as body weight of rats was measured after multiple intravenous injections of polymeric micelles forming from poly(ethylene glycol)-b-poly(aspartate) block copolymer. No pathological toxic side effects were observed at two different doses, followed only by activation of the mononuclear phagocyte system (MPS) in the spleen, liver, lung, bone marrow, and lymph node. This finding confirms the absence of--or the very low level of--in vivo toxicity of the polymeric micelle carriers that were reported in previous animal experiments and clinical results. Then, immunohistochemical analyses with a biotinylated polymeric micelle confirmed specific accumulation of the micelle in the MPS. The immunohistochemical analyses also revealed, first, very rapid and specific accumulation of the micelle in the vasculatures of tumor capsule of rat ascites hepatoma AH109A, and second, the micelle's scanty infiltration into tumor parenchyma. This finding suggests a unique tumor-accumulation mechanism that is very different from simple EPR effect-based tumor targeting.

  5. Design of block-copolymer-based micelles for active and passive targeting

    NARCIS (Netherlands)

    Lebouille, Jérôme G.J.L.; Leermakers, Frans A.M.; Cohen Stuart, Martien A.; Tuinier, Remco

    2016-01-01

    A self-consistent field study is presented on the design of active and passive targeting block-copolymeric micelles. These micelles form in water by self-assembly of triblock copolymers with a hydrophilic middle block and two hydrophobic outer blocks. A minority amount of diblock copolymers with the

  6. Green synthetic, multifunctional hybrid micelles with shell embedded magnetic nanoparticles for theranostic applications.

    Science.gov (United States)

    Li, Yongyong; Ma, Junping; Zhu, Haiyan; Gao, Xiaolong; Dong, Haiqing; Shi, Donglu

    2013-08-14

    The objective of this study is to design and develop a green-synthetic, multifunctional hybrid micelles with shell embedded magnetic nanoparticles for theranostic applications. The hybrid micelles were engineered based on complex micelles self-assembled from amphiphilic block copolymers Pluronic F127 and peptide-amphiphile (PA) pal-AAAAHHHD. The reason to choose PA is due to its amphiphilic character and the coordination capability for Fe(3+) and Fe(2+). The PA incorporation allows the in situ growth of the magnetic iron oxide nanoparticles onto the complex micelles, to yield the nanostructures with shell embedded magnetic nanoparticles at an ambient condition without any organic solvents. The anticancer drug doxorubicin (DOX) can be efficiently loaded into the hybrid micelles. Interestingly, the magnetic nanoparticles anchored on the shell were found to significantly retard the DOX release behavior of the drug loaded hybrid micelles. It was proposed that a cross-linking effect of the shell by magnetic nanoparticles is a key to underlie the above intriguing phenomenon, which could enhance the stability and control the drug diffusion of the hybrid micelles. Importantly, in vitro and in vivo magnetic resonance imaging (MRI) revealed the potential of these hybrid micelles to be served as a T2-weighted MR imaging contrast enhancer for clinical diagnosis.

  7. Preparation and evaluation of novel mixed micelles as nanocarriers for intravenous delivery of propofol

    Directory of Open Access Journals (Sweden)

    Li Xinru

    2011-01-01

    Full Text Available Abstract Novel mixed polymeric micelles formed from biocompatible polymers, poly(ethylene glycol-poly(lactide (mPEG-PLA and polyoxyethylene-660-12-hydroxy stearate (Solutol HS15, were fabricated and used as a nanocarrier for solubilizing poorly soluble anesthetic drug propofol. The solubilization of propofol by the mixed micelles was more efficient than those made of mPEG-PLA alone. Micelles with the optimized composition of mPEG-PLA/Solutol HS15/propofol = 10/1/5 by weight had particle size of about 101 nm with narrow distribution (polydispersity index of about 0.12. Stability analysis of the mixed micelles in bovine serum albumin (BSA solution indicated that the diblock copolymer mPEG efficiently protected the BSA adsorption on the mixed micelles because the hydrophobic groups of the copolymer were efficiently screened by mPEG, and propofol-loaded mixed micelles were stable upon storage for at least 6 months. The content of free propofol in the aqueous phase for mixed micelles was lower by 74% than that for the commercial lipid emulsion. No significant differences in times to unconsciousness and recovery of righting reflex were observed between mixed micelles and commercial lipid formulation. The pharmacological effect may serve as pharmaceutical nanocarriers with improved solubilization capacity for poorly soluble drugs.

  8. The association of low-molecular-weight hydrophobic compounds with native casein micelles in bovine milk.

    Science.gov (United States)

    Cheema, M; Mohan, M S; Campagna, S R; Jurat-Fuentes, J L; Harte, F M

    2015-08-01

    The agreed biological function of the casein micelles in milk is to carry minerals (calcium, magnesium, and phosphorus) from mother to young along with amino acids for growth and development. Recently, native and modified casein micelles were used as encapsulating and delivery agents for various hydrophobic low-molecular-weight probes. The ability of modified casein micelles to bind certain probes may derive from the binding affinity of native casein micelles. Hence, a study with milk from single cows was conducted to further elucidate the association of hydrophobic molecules into native casein micelles and further understand their biological function. Hydrophobic and hydrophilic extraction followed by ultraperformance liquid chromatography-high resolution mass spectrometry analysis were performed over protein fractions obtained from size exclusion fractionation of raw skim milk. Hydrophobic compounds, including phosphatidylcholine, lyso-phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin, showed strong association exclusively to casein micelles as compared with whey proteins, whereas hydrophilic compounds did not display any preference for their association among milk proteins. Further analysis using liquid chromatography-tandem mass spectrometry detected 42 compounds associated solely with the casein-micelles fraction. Mass fragments in tandem mass spectrometry identified 4 of these compounds as phosphatidylcholine with fatty acid composition of 16:0/18:1, 14:0/16:0, 16:0/16:0, and 18:1/18:0. These results support that transporting low-molecular-weight hydrophobic molecules is also a biological function of the casein micelles in milk.

  9. The Role of Decorated SDS Micelles in Sub-CMC Protein Denaturation and Association

    DEFF Research Database (Denmark)

    Andersen, Kell; Oliveira, Cristiano Luis Pinto De; Larsen, K.L.;

    2009-01-01

    . Our data provide key structural insights into decorated micelle complexes with proteins, revealing a remarkable diversity in the different conformations they can stabilize. The data highlight that a minimum decorated micelle size, which may be a key driving force for intermolecular protein association...

  10. Improving anticancer activity and reducing systemic toxicity of doxorubicin by self-assembled polymeric micelles

    Science.gov (United States)

    Gou, MaLing; Shi, HuaShan; Guo, Gang; Men, Ke; Zhang, Juan; Zheng, Lan; Li, ZhiYong; Luo, Feng; Qian, ZhiYong; Zhao, Xia; Wei, YuQuan

    2011-03-01

    In an attempt to improve anticancer activity and reduce systemic toxicity of doxorubicin (Dox), we encapsulated Dox in monomethoxy poly(ethylene glycol)-poly(ɛ-caprolactone) (MPEG-PCL) micelles by a novel self-assembly procedure without using surfactants, organic solvents or vigorous stirring. These Dox encapsulated MPEG-PCL (Dox/MPEG-PCL) micelles with drug loading of 4.2% were monodisperse and ~ 20 nm in diameter. The Dox can be released from the Dox/MPEG-PCL micelles; the Dox-release at pH 5.5 was faster than that at pH 7.0. Encapsulation of Dox in MPEG-PCL micelles enhanced the cellular uptake and cytotoxicity of Dox on the C-26 colon carcinoma cell in vitro, and slowed the extravasation of Dox in the transgenic zebrafish model. Compared to free Dox, Dox/MPEG-PCL micelles were more effective in inhibiting tumor growth in the subcutaneous C-26 colon carcinoma and Lewis lung carcinoma models, and prolonging survival of mice bearing these tumors. Dox/MPEG-PCL micelles also induced lower systemic toxicity than free Dox. In conclusion, incorporation of Dox in MPEG-PCL micelles enhanced the anticancer activity and decreased the systemic toxicity of Dox; these Dox/MPEG-PCL micelles are an interesting formulation of Dox and may have potential clinical applications in cancer therapy.

  11. Molecular dynamics simulations of helical antimicrobial peptides in SDS micelles: what do point mutations achieve?

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Kaznessis, Yiannis N

    2005-01-01

    We report long time scale simulations of the 18-residue helical antimicrobial peptide ovispirin-1 and its analogs novispirin-G10 and novispirin-T7 in SDS micelles. The SDS micelle serves as an economical and effective model for a cellular membrane. Ovispirin, which is initially placed along a mic...

  12. Separation of racemic mixture by ultrafiltration of enantioselective micelles. 2 (De) complexation kinetics

    NARCIS (Netherlands)

    Overdevest, P.E.M.; Schutyser, M.A.I.; Bruin, de T.J.M.; Riet, van 't K.; Keurentjes, J.T.F.; Padt, van der A.

    2001-01-01

    The application of enantioselective micelles in ultrafiltration systems can be an alternative route to meet the increasing demand for enantiopure products. We have studied the separation of D,L-phenylalanine (Phe) by cholesteryl-L-glutamate:CuII (CLG:CuII) anchored in nonionic micelles (intrinsic en

  13. Deoxycholic acid-grafted PEGylated chitosan micelles for the delivery of mitomycin C.

    Science.gov (United States)

    Zhang, Xiu-Rong; Shi, Nian-Qiu; Zhao, Yang; Zhu, He-Yun; Guan, Jiao; Jin, Ying

    2015-06-01

    Mitomycin C (MTC) was incorporated to a micelle system preparing from a polymer named deoxycholic acid chitosan-grafted poly(ethylene glycol) methyl ether (mPEG-CS-DA). mPEG-CS-DA was synthesized and characterized by (1)H nuclear magnetic resonance ((1)H-NMR) and Fourier transform infrared spectroscopy. mPEG-CS-DA formed a core-shell micellar structure with a critical micelle concentration of 6.57 µg/mL. The mPEG-CS-DA micelles were spherical with a hydrodynamic diameter of about 231 nm. After poly(ethylene glycol)ylation of deoxycholic acid chitosan (CS-DA), the encapsulation efficiency and drug loading efficiency increased from 50.62% to 56.42% and from 20.51% to 24.13%, respectively. The mPEG-CS-DA micelles possessed a higher drug release rate than the CS-DA micelles. For pharmacokinetics, the area under the curve (AUC) of the mPEG-CS-DA micelles was 1.5 times higher than that of MTC injection, and these micelles can enhance the bioavailability of MTC. mPEG-CS-DA micelles reduced the distribution of MTC in almost all normal tissues and had the potential to improve the kidney toxicity caused by MTC injection.

  14. Improving anticancer activity and reducing systemic toxicity of doxorubicin by self-assembled polymeric micelles

    Energy Technology Data Exchange (ETDEWEB)

    Gou Maling; Shi Huashan; Guo Gang; Men Ke; Zhang Juan; Li Zhiyong; Luo Feng; Qian Zhiyong; Wei Yuquan [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Zheng Lan; Zhao Xia, E-mail: anderson-qian@163.com [West China Second University Hospital, West China Women' s and Children' s Hospital, Sichuan University, Chengdu 610041 (China)

    2011-03-04

    In an attempt to improve anticancer activity and reduce systemic toxicity of doxorubicin (Dox), we encapsulated Dox in monomethoxy poly(ethylene glycol)-poly({epsilon}-caprolactone) (MPEG-PCL) micelles by a novel self-assembly procedure without using surfactants, organic solvents or vigorous stirring. These Dox encapsulated MPEG-PCL (Dox/MPEG-PCL) micelles with drug loading of 4.2% were monodisperse and {approx} 20 nm in diameter. The Dox can be released from the Dox/MPEG-PCL micelles; the Dox-release at pH 5.5 was faster than that at pH 7.0. Encapsulation of Dox in MPEG-PCL micelles enhanced the cellular uptake and cytotoxicity of Dox on the C-26 colon carcinoma cell in vitro, and slowed the extravasation of Dox in the transgenic zebrafish model. Compared to free Dox, Dox/MPEG-PCL micelles were more effective in inhibiting tumor growth in the subcutaneous C-26 colon carcinoma and Lewis lung carcinoma models, and prolonging survival of mice bearing these tumors. Dox/MPEG-PCL micelles also induced lower systemic toxicity than free Dox. In conclusion, incorporation of Dox in MPEG-PCL micelles enhanced the anticancer activity and decreased the systemic toxicity of Dox; these Dox/MPEG-PCL micelles are an interesting formulation of Dox and may have potential clinical applications in cancer therapy.

  15. Delivery of the photosensitizer Pc 4 in PEG-PCL micelles for in vitro PDT studies.

    Science.gov (United States)

    Master, Alyssa M; Rodriguez, Myriam E; Kenney, Malcolm E; Oleinick, Nancy L; Gupta, Anirban Sen

    2010-05-01

    The silicon phthalocyanine Pc 4 is a second-generation photosensitizer that has several properties superior to other photosensitizers currently approved by the FDA, and it has shown significant promise for photodynamic therapy (PDT) in several cancer cells in vitro and model tumor systems in vivo. However, because of the high hydrophobicity of Pc 4, its formulation for in vivo delivery and favorable biodistribution become challenging. To this end, we are studying encapsulation and delivery of Pc 4 in block copolymer micelles. Here, we report the development of biocompatible PEG-PCL micelle nanoparticles, encapsulation of Pc 4 within the micelle core by hydrophobic association with the PCL block, and in vitro PDT studies of the micelle-formulated Pc 4 in MCF-7c3 human breast cancer cells. Our studies demonstrate efficient encapsulation of Pc 4 in the micelles, intracellular uptake of the micelle-formulated Pc 4 in cells, and significant cytotoxic effect of the formulation upon photoirradiation. Quantitative estimation of the extent of Pc 4 loading in the micelles and the photocytotoxicity of the micelle-incorporated Pc 4 demonstrate the promise of our approach to develop a biocompatible nanomedicine platform for tumor-targeted delivery of Pc 4 for site-selective PDT.

  16. Self-consistent-field calculations of proteinlike incorporations in polyelectrolyte complex micelles

    NARCIS (Netherlands)

    Lindhoud, S.; Cohen Stuart, M.A.; Norde, W.; Leermakers, F.A.M.

    2009-01-01

    Self-consistent field theory is applied to model the structure and stability of polyelectrolyte complex micelles with incorporated protein (molten globule) molecules in the core. The electrostatic interactions that drive the micelle formation are mimicked by nearest-neighbor interactions using

  17. Modeling the Interaction of Dodecylphosphocholine Micelles with the Anticoccidial Peptide PW2 Guided by NMR Data

    Directory of Open Access Journals (Sweden)

    Francisco Gomes-Neto

    2013-08-01

    Full Text Available Antimicrobial peptides are highly dynamic entities that acquire structure upon binding to a membrane interface. To better understand the structure and the mechanism for the molecular recognition of dodecylphosphocholine (DPC micelles by the anticoccidial peptide PW2, we performed molecular dynamics (MD simulations guided by NMR experimental data, focusing on strategies to explore the transient nature of micelles, which rearrange on a millisecond to second timescale. We simulated the association of PW2 with a pre-built DPC micelle and with free-DPC molecules that spontaneously forms micelles in the presence of the peptide along the simulation. The simulation with spontaneous micelle formation provided the adequate environment which replicated the experimental data. The unrestrained MD simulations reproduced the NMR structure for the entire 100 ns MD simulation time. Hidden discrete conformational states could be described. Coulomb interactions are important for initial approximation and hydrogen bonds for anchoring the aromatic region at the interface, being essential for the stabilization of the interaction. Arg9 is strongly attached with phosphate. We observed a helix elongation process stabilized by the intermolecular peptide-micelle association. Full association that mimics the experimental data only happens after complete micelle re-association. Fast micelle dynamics without dissociation of surfactants leads to only superficial binding.

  18. PVA-Sago starch hydrogel and the preliminary clinical animal study of the hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, Kamaruddin; Mohd Dahlan, Khairul Zaman [Malaysian Institute for Nuclear Technology Research, Bangi, Kajang (Malaysia); Halim, Ahmad Sukari; Md Nor, Mohd Tarmizi [Sciences University of Malaysia, School of Medical Sciences, Kerian, Kelantan (Malaysia); Yoshii, Fumio [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-03-01

    Sago starch granule dissolves in hot water to form physically crosslink semi-gel structure. Polyvinyl alcohol (PVA) in aqueous solution is chemically crosslink and form hydrogel after expose to gamma or electron beam irradiation. Combination of sago starch and PVA give tremendous improvement on strength and elasticity of the gel. Adding additive such as carboxymethyl cellulose enhance the swelling or absorption property of the gel. These properties of hydrogel are important for wound dressing application. The preliminary clinical animal study on the PVA Sago hydrogel dressing shows promising results of healing process in comparison with the conventional dressing using vaseline impregnated gauze acting as control dressing. This re-confirmed by biopsy tests on the wound tissue taking during the healing process. The tests show the increasing amount of fibroblast and endothelial cells on both wounds using hydrogel and jalonet during the healing process. Also, the rate of epitheliazation is almost completed for both wounds after 10 days of dressing and the lymphocytes cell increase tremendously for the first 14 days with hydrogel dressing. (author)

  19. Shaping and patterning gold nanoparticles via micelle templated photochemistry

    Science.gov (United States)

    Kundrat, F.; Baffou, G.; Polleux, J.

    2015-09-01

    Shaping and positioning noble metal nanostructures are essential processes that still require laborious and sophisticated techniques to fabricate functional plasmonic interfaces. The present study reports a simple photochemical approach compatible with micellar nanolithography and photolithography that enables the growth, arrangement and shaping of gold nanoparticles with tuneable plasmonic resonances on glass substrates. Ultraviolet illumination of surfaces coated with gold-loaded micelles leads to the formation of gold nanoparticles with micro/nanometric spatial resolution without requiring any photosensitizers or photoresists. Depending on the extra-micellar chemical environment and the illumination wavelength, block copolymer micelles act as reactive and light-responsive templates, which enable to grow gold deformed nanoparticles (potatoids) and nanorings. Optical characterization reveals that arrays of individual potatoids and rings feature a localized plasmon resonance around 600 and 800 nm, respectively, enhanced photothermal properties and high temperature sustainability, making them ideal platforms for future developments in nanochemistry and biomolecular manipulation controlled by near-infrared-induced heat.Shaping and positioning noble metal nanostructures are essential processes that still require laborious and sophisticated techniques to fabricate functional plasmonic interfaces. The present study reports a simple photochemical approach compatible with micellar nanolithography and photolithography that enables the growth, arrangement and shaping of gold nanoparticles with tuneable plasmonic resonances on glass substrates. Ultraviolet illumination of surfaces coated with gold-loaded micelles leads to the formation of gold nanoparticles with micro/nanometric spatial resolution without requiring any photosensitizers or photoresists. Depending on the extra-micellar chemical environment and the illumination wavelength, block copolymer micelles act as

  20. Factors influencing casein micelle size in milk of individual cows: Genetic variants and glycosylation of k-casein

    NARCIS (Netherlands)

    Bijl, E.; Vries, de R.F.M.; Valenberg, van H.J.F.; Huppertz, T.; Hooijdonk, van A.C.M.

    2014-01-01

    The average casein micelle size varies widely between milk samples of individual cows. The factors that cause this variation in size are not known but could provide more insight into casein micelle structure and into the physiology of casein micelle formation. The objective of this research was ther

  1. Quantitative comparison of long-wavelength Alexa Fluor dyes to Cy dyes: fluorescence of the dyes and their bioconjugates.

    Science.gov (United States)

    Berlier, Judith E; Rothe, Anca; Buller, Gayle; Bradford, Jolene; Gray, Diane R; Filanoski, Brian J; Telford, William G; Yue, Stephen; Liu, Jixiang; Cheung, Ching-Ying; Chang, Wesley; Hirsch, James D; Beechem, Joseph M; Haugland, Rosaria P; Haugland, Richard P

    2003-12-01

    Amine-reactive N-hydroxysuccinimidyl esters of Alexa Fluor fluorescent dyes with principal absorption maxima at about 555 nm, 633 nm, 647 nm, 660 nm, 680 nm, 700 nm, and 750 nm were conjugated to antibodies and other selected proteins. These conjugates were compared with spectrally similar protein conjugates of the Cy3, Cy5, Cy5.5, Cy7, DY-630, DY-635, DY-680, and Atto 565 dyes. As N-hydroxysuccinimidyl ester dyes, the Alexa Fluor 555 dye was similar to the Cy3 dye, and the Alexa Fluor 647 dye was similar to the Cy5 dye with respect to absorption maxima, emission maxima, Stokes shifts, and extinction coefficients. However, both Alexa Fluor dyes were significantly more resistant to photobleaching than were their Cy dye counterparts. Absorption spectra of protein conjugates prepared from these dyes showed prominent blue-shifted shoulder peaks for conjugates of the Cy dyes but only minor shoulder peaks for conjugates of the Alexa Fluor dyes. The anomalous peaks, previously observed for protein conjugates of the Cy5 dye, are presumably due to the formation of dye aggregates. Absorption of light by the dye aggregates does not result in fluorescence, thereby diminishing the fluorescence of the conjugates. The Alexa Fluor 555 and the Alexa Fluor 647 dyes in protein conjugates exhibited significantly less of this self-quenching, and therefore the protein conjugates of Alexa Fluor dyes were significantly more fluorescent than those of the Cy dyes, especially at high degrees of labeling. The results from our flow cytometry, immunocytochemistry, and immunohistochemistry experiments demonstrate that protein-conjugated, long-wavelength Alexa Fluor dyes have advantages compared to the Cy dyes and other long-wavelength dyes in typical fluorescence-based cell labeling applications.

  2. Synthesis, characterization, swelling and dye adsorption properties of starch incorporated acrylic gels.

    Science.gov (United States)

    Mandal, Bidyadhar; Ray, Samit Kumar

    2015-11-01

    Several hydrogels were prepared by a free radical polymerization of acrylic acid (AA), sodium acrylate (SA) and AA/hydroxy ethyl methacrylate (HEMA) in the presence of starch in water. These starch incorporated acrylic gels were prepared by varying the concentration of the initiator, monomer, crosslinker and the starch. The resulting gels were characterized by FTIR, SEM, XRD, DTA-TGA, pH at point zero charge (PZC), swelling and the diffusion in water. The gels showed high adsorption and removal% of Safranine T (ST) and Brilliant Cresyl Blue (BCB) dyes from water. The swelling and the adsorption data were fitted to different kinetic models and isotherms. Amongst the three kinds of gels, the starch incorporated sodium polyacrylate gel showed the highest adsorption of 9.7-85.3mg/L (97-61% removal) of BCB dye and 9.1-83mg/L (91-60% removal) of ST dye for a feed dye concentration of 10-140mg/L.

  3. Factors affecting the stability of drug-loaded polymeric micelles and strategies for improvement

    Science.gov (United States)

    Zhou, Weisai; Li, Caibin; Wang, Zhiyu; Zhang, Wenli; Liu, Jianping

    2016-09-01

    Polymeric micelles (PMs) self-assembled by amphiphilic block copolymers have been used as promising nanocarriers for tumor-targeted delivery due to their favorable properties, such as excellent biocompatibility, prolonged circulation time, favorable particle sizes (10-100 nm) to utilize enhanced permeability and retention effect and the possibility for functionalization. However, PMs can be easily destroyed due to dilution of body fluid and the absorption of proteins in system circulation, which may induce drug leakage from these micelles before reaching the target sites and compromise the therapeutic effect. This paper reviewed the factors that influence stability of micelles in terms of thermodynamics and kinetics consist of the critical micelle concentration of block copolymers, glass transition temperature of hydrophobic segments and polymer-polymer and polymer-cargo interaction. In addition, some effective strategies to improve the stability of micelles were also summarized.

  4. Dissipative Particle Dynamics Study on Aggregation of MPEG- PAE-PLA Block Polymer Micelles Loading Doxorubicine

    Institute of Scientific and Technical Information of China (English)

    杨楚芬; 孙尧; 章莉娟; 朱国典; 张灿阳; 钱宇

    2012-01-01

    To guide the molecular design of the pH-sensitive triblock amphiphilic polymer MPEG-PAE-PLA and the for- mula design of its doxorubicine (DOX)-loaded micelles, dissipative particle dynamics (DPD) simulations are em- ployed to investigate the aggregation behaviors of the DOX-loaded micelles. The simulation results showed that the aggregate morphologies of micelles and DOX distribution are influenced by degree of polymerization of blocks, and the proposed structure of polymer is MPEG44-PAE3-PLA4. With different contents of polymer or DOX, differ- ent aggregate morphologies of the micelles, like microsphere, spindle/column, reticulation or lamella are observed. To prepare the micro-spherical DOX-loaded micelles, the polymer content is proposed as 10%--15%, and the DOX content less than 10%.

  5. Effective repair of traumatically injured spinal cord by nanoscale block copolymer micelles

    Science.gov (United States)

    Shi, Yunzhou; Kim, Sungwon; Huff, Terry B.; Borgens, Richard B.; Park, Kinam; Shi, Riyi; Cheng, Ji-Xin

    2010-01-01

    Spinal cord injury results in immediate disruption of neuronal membranes, followed by extensive secondary neurodegenerative processes. A key approach for repairing injured spinal cord is to seal the damaged membranes at an early stage. Here, we show that axonal membranes injured by compression can be effectively repaired using self-assembled monomethoxy poly(ethylene glycol)-poly(D,L-lactic acid) di-block copolymer micelles. Injured spinal tissue incubated with micelles (60 nm diameter) showed rapid restoration of compound action potential and reduced calcium influx into axons for micelle concentrations much lower than the concentrations of polyethylene glycol, a known sealing agent for early-stage spinal cord injury. Intravenously injected micelles effectively recovered locomotor function and reduced the volume and inflammatory response of the lesion in injured rats, without any adverse effects. Our results show that copolymer micelles can interrupt the spread of primary spinal cord injury damage with minimal toxicity.

  6. The influence of bile acids on the oral bioavailability of vitamin K encapsulated in polymeric micelles.

    Science.gov (United States)

    van Hasselt, P M; Janssens, G E P J; Slot, T K; van der Ham, M; Minderhoud, T C; Talelli, M; Akkermans, L M; Rijcken, C J F; van Nostrum, C F

    2009-01-19

    The purpose of this study was to assess the ability of polymeric micelles to enable gastrointestinal absorption of the extremely hydrophobic compound vitamin K, by comparison of its absorption in bile duct ligated and sham operated rats. Hereto, vitamin K was encapsulated in micelles composed of mPEG(5000)-b-p(HPMAm-lac(2)), a thermosensitive block copolymer. Vitamin K plasma levels rose significantly upon gastric administration of 1 mg vitamin K encapsulated in polymeric micelles in sham operated rats, but not after bile duct ligation (AUC 4543 and 1.64 ng/mL/h respectively, pvitamin K from polymeric micelles is mediated by free bile and that uptake of intact micelles through pinocytosis is insignificant.

  7. Tumor homing indocyanine green encapsulated micelles for near infrared and photoacoustic imaging of tumors.

    Science.gov (United States)

    Uthaman, Saji; Bom, Joon-suk; Kim, Hyeon Sik; John, Johnson V; Bom, Hee-Seung; Kim, Seon-Jong; Min, Jung-Joon; Kim, Il; Park, In-Kyu

    2016-05-01

    Photoacoustic imaging (PAI) is an emerging analytical modality that is under intense preclinical development for the early diagnosis of various medical conditions, including cancer. However, the lack of specific tumor targeting by various contrast agents used in PAI obstructs its clinical applications. In this study, we developed indocyanine green (ICG)-encapsulated micelles specific for the CD 44 receptor and used in near infrared and photoacoustic imaging of tumors. ICG was hydrophobically modified prior to loading into hyaluronic acid (HA)-based micelles utilized for CD 44 based-targeting. We investigated the physicochemical characteristics of prepared HA only and ICG-encapsulated HA micelles (HA-ICG micelles). After intravenous injection of tumor-bearing mice, the bio-distribution and in vivo photoacoustic images of ICG-encapsulated HA micelles accumulating in tumors were also investigated. Our study further encourages the application of this HA-ICG-based nano-platform as a tumor-specific contrast agent for PAI.

  8. Micelle structural studies on oil solubilization by a small-angle neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Putra, Edy Giri Rachman [Neutron Science Division, HANARO Center, Korea Atomic Energy Research Institute (KAERI), 1045 Daedok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia)], E-mail: giri@batan.go.id; Seong, Baek Seok [Neutron Science Division, HANARO Center, Korea Atomic Energy Research Institute (KAERI), 1045 Daedok-daero, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Ikram, Abarrul [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia)

    2009-02-21

    A small-angle neutron scattering (SANS) technique was applied to reveal the micelle structural changes. The micelle structural changes of 0.3 M sodium dodecyl sulfate (SDS) concentration by addition of various oil, i.e. n-hexane, n-octane, and n-decane up to 60% (v/v) have been investigated. It was found that the size, aggregation number and the structures of the micelles changed exhibiting that the effective charge on the micelle decreases with an addition of oil. There was a small increase in minor axis of micelle while the correlation peak shifted to a lower momentum transfer Q and then to higher Q by a further oil addition.

  9. Tuning intermicellar potential of Triton X-100– anthranilic acid mixed micelles

    Indian Academy of Sciences (India)

    Gunjan Verma; V K Aswal; S K Kulshreshtha; C Manohar; P A Hassan; Eric W Kaler

    2008-11-01

    Structural parameters of micelles formed by Triton X-100 in the presence of solubilized anthranilic acid at different pH values was investigated using light scattering and small angle neutron scattering. Analysis of the SANS data indicate that micelles are oblate ellipsoidal in nature with little variation in the dimensions, in the investigated pH range (from 0.5 to 6.0). The interaction potential of the micelles shows a minimum closer to the isoelectric point of anthranilic acid. A similar variation is observed in the cloud point of the micelles with pH. The observed variation in the interaction potential with pH of the micellar solution can be explained in terms of the reversal of charge on anthranilic acid due to shift in the acid–base equilibrium. The variation in interaction potential and cloud point with pH is modelled using Coulombic repulsion of charged molecules at the micelle interface.

  10. Effective repair of traumatically injured spinal cord by nanoscale block copolymer micelles.

    Science.gov (United States)

    Shi, Yunzhou; Kim, Sungwon; Huff, Terry B; Borgens, Richard B; Park, Kinam; Shi, Riyi; Cheng, Ji-Xin

    2010-01-01

    Spinal cord injury results in immediate disruption of neuronal membranes, followed by extensive secondary neurodegenerative processes. A key approach for repairing injured spinal cord is to seal the damaged membranes at an early stage. Here, we show that axonal membranes injured by compression can be effectively repaired using self-assembled monomethoxy poly(ethylene glycol)-poly(d,l-lactic acid) di-block copolymer micelles. Injured spinal tissue incubated with micelles (60 nm diameter) showed rapid restoration of compound action potential and reduced calcium influx into axons for micelle concentrations much lower than the concentrations of polyethylene glycol, a known sealing agent for early-stage spinal cord injury. Intravenously injected micelles effectively recovered locomotor function and reduced the volume and inflammatory response of the lesion in injured rats, without any adverse effects. Our results show that copolymer micelles can interrupt the spread of primary spinal cord injury damage with minimal toxicity.

  11. Crafting threads of diblock copolymer micelles via flow-enabled self-assembly.

    Science.gov (United States)

    Li, Bo; Han, Wei; Jiang, Beibei; Lin, Zhiqun

    2014-03-25

    Hierarchically assembled amphiphilic diblock copolymer micelles were exquisitely crafted over large areas by capitalizing on two concurrent self-assembling processes at different length scales, namely, the periodic threads composed of a monolayer or a bilayer of diblock copolymer micelles precisely positioned by flow-enabled self-assembly (FESA) on the microscopic scale and the self-assembly of amphiphilic diblock copolymer micelles into ordered arrays within an individual thread on the nanometer scale. A minimum spacing between two adjacent threads λmin was observed. A model was proposed to rationalize the relationship between the thread width and λmin. Such FESA of diblock copolymer micelles is remarkably controllable and easy to implement. It opens up possibilities for lithography-free positioning and patterning of diblock copolymer micelles for various applications in template fabrication of periodic inorganic nanostructures, nanoelectronics, optoelectronics, magnetic devices, and biotechnology.

  12. Synthesis of Cross-Linked Polymeric Micelle pH Nanosensors

    DEFF Research Database (Denmark)

    Ek, Pramod Kumar; Jølck, Rasmus Irming; Andresen, Thomas Lars

    2015-01-01

    at the micelle shell using CuAAC results in a stabilized micelle pH nanosensor. Compared to the postmicelle modification strategy, the mixed-micellization approach increases the control of the overall composition of the nanosensors.Both approaches provide stable nanosensors with similar pKa profiles and thereby......The design flexibility that polymeric micelles offer in the fabrication of optical nanosensors for ratiometric pH measurements is investigated. pH nanosensors based on polymeric micelles are synthesized either by a mixed-micellization approach or by a postmicelle modification strategy. In the mixed......-micellization approach, self-assembly of functionalized unimers followed by shell cross-linking by copper-catalyzed azide-alkyne cycloaddition (CuAAC) results in stabilized cRGD-functionalized micelle pH nanosensors. In the postmicelle modification strategy, simultaneous cross-linking and fluorophore conjugation...

  13. Preparation of stable spherical micelles with rigid backbones based on polyaryletherketone copolymers containing lateral pyridyl groups

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuling; Liu, Lingzhi; Guo, Yunliang; Jiang, Zhenhua; Wang, Guibin, E-mail: wgb@jlu.edu.cn

    2013-07-15

    A new bisphenol monomer, 3-(3,4-dihydroxyphenylimine) pyridine (PYPH), was synthesized via a deoxidization reaction of an amine. A series of novel polyaryletherketone copolymers containing lateral pyridyl groups (PY-PAEKs) based on PYPH, 2,2-di(4-hydroxyphenyl)propane and 4,4′-difluorobenzophenone were prepared by nucleophilic aromatic substitution polycondensation reactions. Furthermore, spherical micelles with rigid PY-PAEKs as the inner cores and flexible polyacrylic acid (PAA) as the outer shells were obtained in a selective solvent (H{sub 2}O) successfully. The formation of the spherical micelles was confirmed by scanning electron and transmission electron microscopy as well as by surface tension measurements. The formation and size of the spherical micelles depended on the weight ratio of PAA/PY-PAEK, the concentration and pH value of the mixed solution containing the PY-PAEK and PAA, and the number of pyridyl groups in the PY-PAEK. The structure of the spherical micelles could be stabilized by a cross-linking reaction between the pyridyl groups of the PY-PAEKs and 1,4-dibromobutane. The diameter of the spherical micelles decreased because of the removal of the PAA shell from the PY-PAEK core after the cross-linking reaction. The resulting stable spherical micelles with rigid backbones did not dissolve in a number of polar solvents and remained unaffected by changes in the pH values. - Graphical abstract: Display Omitted - Highlights: • Polyaryletherketone copolymers containing lateral pyridyl groups were synthesized. • Spherical micelles were prepared using these copolymers and polyacrylic acid. • The copolymers and polyacrylic acid formed the core and the shell of the micelles, respectively. • The obtained micelles were stabilized by a cross-linking reaction. • The cross-linked micelles had rigid backbones, independent of solvents and pH values.

  14. Curcumin-loaded biodegradable polymeric micelles for colon cancer therapy in vitro and in vivo

    Science.gov (United States)

    Gou, Maling; Men, Ke; Shi, Huashan; Xiang, Mingli; Zhang, Juan; Song, Jia; Long, Jianlin; Wan, Yang; Luo, Feng; Zhao, Xia; Qian, Zhiyong

    2011-04-01

    Curcumin is an effective and safe anticancer agent, but its hydrophobicity inhibits its clinical application. Nanotechnology provides an effective method to improve the water solubility of hydrophobic drug. In this work, curcumin was encapsulated into monomethoxy poly(ethylene glycol)-poly(ε-caprolactone) (MPEG-PCL) micelles through a single-step nano-precipitation method, creating curcumin-loaded MPEG-PCL (Cur/MPEG-PCL) micelles. These Cur/MPEG-PCL micelles were monodisperse (PDI = 0.097 +/- 0.011) with a mean particle size of 27.3 +/- 1.3 nm, good re-solubility after freeze-drying, an encapsulation efficiency of 99.16 +/- 1.02%, and drug loading of 12.95 +/- 0.15%. Moreover, these micelles were prepared by a simple and reproducible procedure, making them potentially suitable for scale-up. Curcumin was molecularly dispersed in the PCL core of MPEG-PCL micelles, and could be slow-released in vitro. Encapsulation of curcumin in MPEG-PCL micelles improved the t1/2 and AUC of curcuminin vivo. As well as free curcumin, Cur/MPEG-PCL micelles efficiently inhibited the angiogenesis on transgenic zebrafish model. In an alginate-encapsulated cancer cell assay, intravenous application of Cur/MPEG-PCL micelles more efficiently inhibited the tumor cell-induced angiogenesisin vivo than that of free curcumin. MPEG-PCL micelle-encapsulated curcumin maintained the cytotoxicity of curcumin on C-26 colon carcinoma cellsin vitro. Intravenous application of Cur/MPEG-PCL micelle (25 mg kg-1curcumin) inhibited the growth of subcutaneous C-26 colon carcinoma in vivo (p colon carcinoma through inhibiting angiogenesis and directly killing cancer cells.

  15. PEG-OCL micelles for quercetin solubilization and inhibition of cancer cell growth.

    Science.gov (United States)

    Khonkarn, Ruttiros; Mankhetkorn, Samlee; Hennink, Wim E; Okonogi, Siriporn

    2011-10-01

    In this study, quercetin (QCT), a flavonoid with high anticancer potential, was loaded into polymeric micelles of PEG-OCL (poly(ethylene glycol)-b-oligo(ε-caprolactone)) with naphthyl or benzyl end groups in order to increase its aqueous solubility. The cytostatic activity of the QCT-loaded micelles toward different human cancer cell lines and normal cells was investigated. The results showed that the solubility of QCT entrapped in mPEG750-b-OCL micelles was substantially increased up to 1 mg/ml, which is approximately 110 times higher than that of its solubility in water (9 μg/ml). The average particle size of QCT-loaded micelles ranged from 14 to 19 nm. The QCT loading capacity of the polymeric micelles with naphthyl groups was higher than that with benzyl groups (10% and 6%, respectively). QCT-loaded, benzyl- and naphthyl-modified micelles effectively inhibited the growth of both sensitive and resistance cancer cells (human erythromyelogenous leukemia cells (K562) and small lung carcinoma cells (GLC4)). However, the benzyl-modified micelles have a good cytocompatibility (in the concentration range investigated (up to 100 μg/ml), they are well tolerated by living cells), whereas their naphthyl counterparts showed some cytotoxicity at higher concentrations (60-100 μg/ml). Flow cytometry demonstrated that the mechanism underlying the growth inhibitory effect of QCT in its free form was inducing cell cycle arrest at the G2/M phase. Benzyl-modified micelles loaded with QCT also exhibited this cycle arresting the effect of cancer cells. In conclusion, this paper shows the enhancement of solubility and cell cycle arrest of QCT loaded into micelles composed of mPEG750-b-OCL modified with benzyl end groups. These micelles are therefore considered to be an attractive vehicle for the (targeted) delivery of QCT to tumors.

  16. LIQUID DYES'CHARACTERISTICS IN DYEING WASTE PAPER PULP AND THEIR APPLICATION

    Institute of Scientific and Technical Information of China (English)

    Xiaoping Wang; gang Chen; Aimin Tang; Hongwei Zhang

    2004-01-01

    In this paper, some liquid dyes were used to dye the waste paper pulp (OCC pulp and waste cement sack paper pulp), and their dyeing characteristics were analyzed, The liquid dyes include liquid basic yellow, liquid basic blue, liquid basic red, liquid basic orange, liquid basic brown and liquid direct black. We found that, each dye had its own dyeing characteristic while dyeing the waste paper pulp.Generally different types of liquid dyes were combined to dye the waste paper pulp, which the adding process must be noticed. We also observed that a black pigment could be applied together with said liquid dyes to dye or adjust the color of the bottom sheet for the fireproof board. We could also achieve the same dyeing result through different combinations of different dyes.

  17. Poly(N-vinylpyrrolidone) hydrogels. Pt. 2; Hydrogel composites as wound dressing for tropical environment

    Energy Technology Data Exchange (ETDEWEB)

    Hilmy, N.; Darwis, D.; Hardiningsih, L. (Center for the Application of Isotopes and Radiation, BATAN, Jakarta (Indonesia))

    The effects of irradiation on hydration and other properties of poly(vinylpyrrolidone) (PVP) hydrogel composites have been investigated. The aqueous solution of vinylpyrrolidone (VP) 10 wt % was mixed with several additives such as agar and polyethylene glycol (PEG). The solution was then irradiated with gamma rays from a Cobalt-60 source at room temperature. Several parameters such as elongation at break (EB), tensile strength (TS), degree of swelling (DS), water vapor transmission rate (WVTR), equilibrium water content (EWC), microbial growth and penetration tests, and water activity (Aw) were analysed at room temperature of 29 [+-] 2[sup o]C humidity of 80 [+-] 10%. Such hydrogel membranes exhibit the following properties: they are elastic, transparent, flexible, impermeable for bacteria. They absorb a high capacity of water, attach to healthy skin but not to the wound and they are easy to remove. These properties of the hydrogel membranes allow application as a wound dressing in a tropical environment. (author).

  18. Piezoresistive Chemical Sensors Based on Functionalized Hydrogels

    Directory of Open Access Journals (Sweden)

    Margarita Guenther

    2014-06-01

    Full Text Available Thin films of analyte-specific hydrogels were combined with microfabricated piezoresistive pressure transducers to obtain chemomechanical sensors that can serve as selective biochemical sensors for a continuous monitoring of metabolites. The gel swelling pressure has been monitored in simulated physiological solutions by means of the output signal of piezoresistive sensors. The interference by fructose, human serum albumin, pH, and ionic concentration on glucose sensing was studied. With the help of a database containing the calibration curves of the hydrogel-based sensors at different values of pH and ionic strength, the corrected values of pH and glucose concentration were determined using a novel calibration algorithm.

  19. Protease-degradable electrospun fibrous hydrogels

    Science.gov (United States)

    Wade, Ryan J.; Bassin, Ethan J.; Rodell, Christopher B.; Burdick, Jason A.

    2015-03-01

    Electrospun nanofibres are promising in biomedical applications to replicate features of the natural extracellular matrix (ECM). However, nearly all electrospun scaffolds are either non-degradable or degrade hydrolytically, whereas natural ECM degrades proteolytically, often through matrix metalloproteinases. Here we synthesize reactive macromers that contain protease-cleavable and fluorescent peptides and are able to form both isotropic hydrogels and electrospun fibrous hydrogels through a photoinitiated polymerization. These biomimetic scaffolds are susceptible to protease-mediated cleavage in vitro in a protease dose-dependent manner and in vivo in a subcutaneous mouse model using transdermal fluorescent imaging to monitor degradation. Importantly, materials containing an alternate and non-protease-cleavable peptide sequence are stable in both in vitro and in vivo settings. To illustrate the specificity in degradation, scaffolds with mixed fibre populations support selective fibre degradation based on individual fibre degradability. Overall, this represents a novel biomimetic approach to generate protease-sensitive fibrous scaffolds for biomedical applications.

  20. Biomimetic Membrane Arrays on Cast Hydrogel Supports

    DEFF Research Database (Denmark)

    Roerdink-Lander, Monique; Ibragimova, Sania; Rein Hansen, Christian;

    2011-01-01

    Lipid bilayers are intrinsically fragile and require mechanical support in technical applications based on biomimetic membranes. Tethering the lipid bilayer membranes to solid substrates, either directly through covalent or ionic substrate−lipid links or indirectly on substrate-supported cushions......, provides mechanical support but at the cost of small molecule transport through the membrane−support sandwich. To stabilize biomimetic membranes while allowing transport through a membrane−support sandwich, we have investigated the feasibility of using an ethylene tetrafluoroethylene (ETFE......)/hydrogel sandwich as the support. The sandwich is realized as a perforated surface-treated ETFE film onto which a hydrogel composite support structure is cast. We report a simple method to prepare arrays of lipid bilayer membranes with low intrinsic electrical conductance on the highly permeable, self...