Swelling properties of cassava starch grafted with poly (potassium acrylate-co-acrylamide) superabsorbent hydrogel prepared by ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Barleany, Dhena Ria, E-mail: dbarleany@yahoo.com; Ulfiyani, Fida; Istiqomah, Shafina; Rahmayetty [Department of Chemical Engineering, University of Sultan Ageng Tirtayasa, Cilegon, Banten (Indonesia); Heriyanto, Heri; Erizal [Centre for Application of Isotopes and Radiation, Jakarta (Indonesia)

2015-12-29

Natural and synthetic hydrophylic polymers can be phisically or chemically cross-linked in order to produce hydrogels. Starch based hydrogels grafted with copolymers from acrylic acid or acrylamide have become very popular for water absorbent application. Superabsorbent hydrogels made from Cassava starch grafted with poly (potassium acrylate-co-acrylamide) were prepared by using of ϒ-irradiation method. Various important parameters such as irradiation doses, monomer to Cassava starch ratio and acrylamide content were investigated. The addition of 7,5 % w w{sup −1} acrylamide into the reaction mixture generated a starch graft copolymer with a water absorption in distilled water as high as 460 g g{sup −1} of its dried weight. The effectivity of hydrogel as superabsorbent for aqueous solutions of NaCl and urea was evaluated. The obtained hydrogel showed the maximum absorptions of 317 g g{sup −1} and 523 g g{sup −1} for NaCl and urea solution, respectively (relative to its own dry weight). The structure of the graft copolymer was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM)

PIXE investigation of in vitro release of chloramphenicol across polyvinyl alcohol/acrylamide hydrogel

International Nuclear Information System (INIS)

Rihawy, M.S.; Alzier, A.; Allaf, A.W.

2011-01-01

Hydrogels based on polyvinyl alcohol and different amounts of acrylamide monomer were prepared by thermal cross-linking in the solid state. The hydrogels were investigated for drug delivery system applications. Chloramphenicol was adopted as a model drug to study its release behavior. Particle induced X-ray emission was utilized to study the drug release behavior across the hydrogels and a comparison study with ultraviolet measurements was performed. Fourier Transform Infrared measurements were carried out for molecular characterization. The releasing behavior of the drug exhibits a decrease and a subsequent increase in the release rate, as the acrylamide monomer increases. Characterization of the hydrogels has shown a competitive behavior between crosslinking with AAm acrylamide monomer or oligomerized version, depending on the amount added to prepare the hydrogels.

INAA of polyacrylic hydrogels of pharmaceutical grade

International Nuclear Information System (INIS)

Ponta, C.; Salagean, M.; Pantelica, A.; Georgescu, I.I.

1998-01-01

, higher values were found for Cr, (8.6±0.1) ppm, and Co, (149±6) ppb. Moreover, Br, As and Sb are present at the following levels: tens of ppb (Br), hundreds of ppb (As, Sb). In conclusion, in the procedure to obtain the polyacrylic acid hydrogels of pharmaceutical grade the raw components can be used with no additional purification, the elements like Zn, Fe, Cr in the final product being at the admissible level. Also, the most suitable milling procedure was chosen to be the ICPR mill. (authors)

Preparation and characterization of polyacrylamide-modified kaolinite containing poly [acrylic acid-co-methylene bisacrylamide] nanocomposite hydrogels

DEFF Research Database (Denmark)

Zaharia, Anamaria; Sarbu, Andrei; Radu, Anita-Laura

2015-01-01

Novel nanocomposite hydrogel structures based on cross-linked poly(acrylic acid) (PAA) and kaolinite (Kaol), modified with different loadings of polyacrylamide (PAAm), were prepared by inverse dispersion polymerization. Ceric ammonium nitrate as an initiator in the presence of nitric acid was used...... of Kaol particles in the polyacrylic acid matrix, thereby leading to enhanced interactions and furthermore to improved mechanical properties of the final hydrogels....

Photonic crystal fiber interferometric pH sensor based on polyvinyl alcohol/polyacrylic acid hydrogel coating.

Science.gov (United States)

Hu, Pengbing; Dong, Xinyong; Wong, Wei Chang; Chen, Li Han; Ni, Kai; Chan, Chi Chiu

2015-04-01

We present a simple photonic crystal fiber interferometer (PCFI) that operates in reflection mode for pH measurement. The sensor is made by coating polyvinyl alcohol/polyacrylic acid (PVA/PAA) hydrogel onto the surface of the PCFI, constructed by splicing a stub of PCF at the distal end of a single-mode fiber with its free end airhole collapsed. The experimental results demonstrate a high average sensitivity of 0.9 nm/pH unit for the 11 wt.% PVA/PAA coated sensor in the pH range from 2.5 to 6.5. The sensor also displays high repeatability and stability and low cross-sensitivity to temperature. Fast, reversible rise and fall times of 12 s and 18 s, respectively, are achieved for the sensor time response.

Studies on radiation synthesis of polyethyleneimine/acrylamide hydrogels

Energy Technology Data Exchange (ETDEWEB)

Francis, Sanju [ISOMED, Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India); Varshney, Lalit [ISOMED, Radiation Technology Development Section, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India)]. E-mail: lalitv@magnum.barc.ernet.in; Tirumalesh, K. [Isotope Application Division, Bhabha Atomic Research Centre, Trombay, Mumbai - 400 085 (India)

2006-07-15

Polyethyleneimine(PEI)/acrylamide(AAM) hydrogels were synthesized by {gamma}-radiation-induced polymerization/crosslinking of aqueous mixtures containing different ratios of PEI and AAM. The gel percentage and equilibrium degree of swelling (EDS) of the synthesized hydrogels were investigated. The compositions of the hydrogels produced were found to be different from the feed composition. Ion-chromatography technique was used to determine the amount of Pb (II) and Cd (II) absorbed by the hydrogel. The maximum binding capacity of the PEI/AAM hydrogels, for Pb and Cd was found to be 19 and 12.6 mg/g, respectively (at 100 ppm). PEI/AAM hydrogels had better metal uptake efficiency than the pure AAM hydrogel at concentrations less than 50 ppm. Pure PEI was observed to be highly degrading type polymer on exposure to gamma radiation. TGA and FT-IR techniques were used to characterize the prepared hydrogels.

Glucose-Sensitive Hydrogel Optical Fibers Functionalized with Phenylboronic Acid.

Science.gov (United States)

Yetisen, Ali K; Jiang, Nan; Fallahi, Afsoon; Montelongo, Yunuen; Ruiz-Esparza, Guillermo U; Tamayol, Ali; Zhang, Yu Shrike; Mahmood, Iram; Yang, Su-A; Kim, Ki Su; Butt, Haider; Khademhosseini, Ali; Yun, Seok-Hyun

2017-04-01

Hydrogel optical fibers are utilized for continuous glucose sensing in real time. The hydrogel fibers consist of poly(acrylamide-co-poly(ethylene glycol) diacrylate) cores functionalized with phenylboronic acid. The complexation of the phenylboronic acid and cis-diol groups of glucose enables reversible changes of the hydrogel fiber diameter. The analyses of light propagation loss allow for quantitative glucose measurements within the physiological range. © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controlled swelling and adsorption properties of polyacrylate/montmorillonite composites

Energy Technology Data Exchange (ETDEWEB)

Natkanski, Piotr [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Kustrowski, Piotr, E-mail: kustrows@chemia.uj.edu.pl [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Bialas, Anna; Piwowarska, Zofia [Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Krakow (Poland); Michalik, Marek [Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Krakow (Poland)

2012-10-15

A series of novel polyacrylate/montmorillonite composites was synthesized by in situ polymerization in aqueous slurry of clay. Dissociated (obtained by adding ammonium or sodium hydroxide) and undissociated forms of acrylic acid were used as monomers in the hydrogel synthesis. The structure and composition of the samples were studied by powder X-ray diffraction, diffuse reflectance infra-red Fourier transform spectroscopy, thermogravimetry and elemental analysis. It has been found that the kind of monomer influences strongly the location of a polymer chain in the formed composite. Complete intercalation of hydrogel into the interlayer space of montmorillonite was observed for sodium polyacrylate, whereas polyacrylic acid and ammonium polyacrylate mainly occupied the outer surface of the clay. The position of hydrogel determined the swelling and adsorption properties of the studied composites. The important factor influencing the kinetics of Fe(III) cation adsorption was pH. The analysis of adsorption isotherms allowed to propose the mechanism of Fe(III) cation adsorption. Highlights: Black-Right-Pointing-Pointer Polyacrylate hydrogels can be introduced into the interlayers of clay. Black-Right-Pointing-Pointer The position of hydrogel in the composite depends on the polymer type. Black-Right-Pointing-Pointer Ammonium polyacrylate places outside the clay, sodium one is intercalated into it. Black-Right-Pointing-Pointer Swelling and adsorption capacities can be controlled by the polymer position. Black-Right-Pointing-Pointer High adsorption efficiency in Fe(III) removal was observed.

Cation Exchange Efficiency Of Modified Bentonite Using In-Situ GAMMA Radiation Polymerization Of Acrylic Acid Or Acrylamide

International Nuclear Information System (INIS)

ISMAIL, S.A.; FALAZI, B.

2009-01-01

Modified bentonites as cation exchangers were prepared by treating raw bentonite with 3N NaOH at 95 0 C followed by in-situ polymerization using gamma irradiation as well as hydrogen peroxide initiation of acrylic acid or acrylamide in the matrix.Water swelling and acid capacity were determined and cation exchange capacity for Cu 2+ , Ni 2+ and Co 2+ was evaluated. It has been found that catiexchange capacity of treated bentonite was increased as result of formed polyacrylic acid and polyacrylamide in the matrix. In case of acrylic acid, the maximum cation exchange capacities of 3.5, 3.1 and 2.5 mg equivalent/g were determined for Cu 2+ , Ni 2+ and Co 2+ , respectively, and for acrylamide, the corresponding capacities were 2.9, 2.8 and 2.6 mg equivalent/g, respectively. Water swelling was found to be associated with holding large amounts of water, for instance, 49 g of water was sorbed per one gram of the sodium salt form of polyacrylic acid in bentonite matrix, in other words the degree of swelling in water achieved 4500%.

Improved Concrete Materials with Hydrogel-Based Internal Curing Agents

Directory of Open Access Journals (Sweden)

Matthew J. Krafcik

2017-11-01

Full Text Available This research article will describe the design and use of polyelectrolyte hydrogel particles as internal curing agents in concrete and present new results on relevant hydrogel-ion interactions. When incorporated into concrete, hydrogel particles release their stored water to fuel the curing reaction, resulting in reduced volumetric shrinkage and cracking and thus increasing concrete service life. The hydrogel’s swelling performance and mechanical properties are strongly sensitive to multivalent cations that are naturally present in concrete mixtures, including calcium and aluminum. Model poly(acrylic acid(AA-acrylamide(AM-based hydrogel particles with different chemical compositions (AA:AM monomer ratio were synthesized and immersed in sodium, calcium, and aluminum salt solutions. The presence of multivalent cations resulted in decreased swelling capacity and altered swelling kinetics to the point where some hydrogel compositions displayed rapid deswelling behavior and the formation of a mechanically stiff shell. Interestingly, when incorporated into mortar, hydrogel particles reduced mixture shrinkage while encouraging the formation of specific inorganic phases (calcium hydroxide and calcium silicate hydrate within the void space previously occupied by the swollen particle.

Gold recovery onto poly(acrylamide-allylthiourea) hydrogels synthesized by treating with gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Kilic, A. Guelden [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey); Malci, Savas [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey); Celikbicak, Oemuer [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey); Sahiner, Nurettin [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey); Salih, Bekir [Hacettepe University, Department of Chemistry, 06532 Ankara (Turkey)]. E-mail: bekir@hacettepe.edu.tr

2005-08-15

Poly(acrylamide-1-allyl-2-thiourea) hydrogels, Poly(AAm-ATU), were synthesized by gamma irradiation using a {sup 60}Co {gamma} source at different irradiation dose rates and in a monomer mixture with different 1-allyl-2-thiourea contents. These hydrogels were used for the specific gold recovery from single and competitive media. It was observed that the gold adsorption capacity onto the hydrogels was high at low pHs and reached a maximum value at pH 0.5. It was found that the adsorption capacity of the hydrogels for gold ions in acidic media around pH 0.5 was high and about 940 mg g{sup -1} dry hydrogel. Adsorption of these hydrogels for gold ions was found to be very fast and also these hydrogels were showed extremely high selectivity to the gold ions in acidic media even when the concentrations of the other metal ions were extremely higher than that of the gold. Because of the high specificity of these hydrogels to gold ions compared with the other metal ions at low pHs, all matrix effects could be easily eliminated by adsorbing gold ions onto the hydrogels at around pH 0.5 and desorbing into 0.8 M thiourea in 3.0 M HCl. The swellability of the synthesized hydrogels varied with irradiation dose rates and increased at high irradiation dose rates. The minimum swellability of the hydrogels was found to be at least 1000% which made it attractive for gold to penetrate into the hydrogels and react with all the functional groups in the interior surface of the hydrogels.

Study of the contribution of the state of water to the gel properties of a photocrosslinked polyacrylic acid hydrogel using magnetic resonance imaging.

Science.gov (United States)

Onuki, Yoshinori; Hasegawa, Naoki; Kida, Chihiro; Obata, Yasuko; Takayama, Kozo

2014-11-01

Photocrosslinked polyacrylic acid (PAA-HEMA) hydrogels are a promising candidate for use in dermatological patch adhesives. To gain further knowledge about the properties of this gel, we investigated the T1 relaxation time and the diffusion coefficient (D) of water in the hydrogels using magnetic resonance (MR) imaging. Hydrogels with different formulations and process factors were prepared and tested. The observed data were analyzed by ANOVA, which clarified the mode of action of the formulation and process factors based on these MR parameters. Various gel properties (i.e., gel fraction, swelling capacity, gel strength, and water-retention ability) were also measured, followed by a Bayesian network (BN) analysis. The BN allowed us to summarize well the relationships between the formulation and process factors, MR parameters, and gel properties. T1 was associated with the swelling and water-retention properties of the hydrogel, whereas D was associated with gel formation and gel strength. Furthermore, this study clarified that T1 and D mostly represented the hydration and water-compartmentalization effects of the hydrogel, respectively. In conclusion, the state of water seems to play an important role in the properties of the PAA-HEMA hydrogel. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Synthesis of porous poly(acrylamide hydrogels using calcium carbonate and its application for slow release of potassium nitrate

Directory of Open Access Journals (Sweden)

2009-05-01

Full Text Available Porous poly(acrylamide was synthesized using calcium carbonate microparticles and subsequent acid treatment to remove the calcium carbonate. Methylenebisacrylamide and ammonium persulfate/sodium metabisulfite were used as crosslinking agent and redox initiator, respectively. The porous structure of resulted hydrogels was confirmed using SEM micrographs. The effect of methylenebisacrylamide concentration and calcium carbonate amount on the swelling of the hydrogels was investigated. The results showed that the effect of methylenebisacrylamide and calcium carbonate variables on the swelling is reverse. The hydrogels were subsequently utilized for the loading of potassium nitrate. Potassium nitrate as active agent was loaded into hydrogels and subsequently the release of this active agent was investigated. In these series of investigation, the effect of content of loading, methylenebisacrylamide and calcium carbonate amount on the release of potassium nitrate from hydrogels was investigated.

Swelling of Superabsorbent Poly(Sodium-Acrylate Acrylamide) Hydrogels and Influence of Chemical Structure on Internally Cured Mortar

Science.gov (United States)

Krafcik, Matthew J.; Erk, Kendra A.

Superabsorbent hydrogel particles show promise as internal curing agents for high performance concrete (HPC). These gels can absorb and release large volumes of water and offer a solution to the problem of self-dessication in HPC. However, the gels are sensitive to ions naturally present in concrete. This research connects swelling behavior with gel-ion interactions to optimize hydrogel performance for internal curing, reducing the chance of early-age cracking and increasing the durability of HPC. Four different hydrogels of poly(sodium-acrylate acrylamide) are synthesized and characterized with swelling tests in different salt solutions. Depending on solution pH, ionic character, and gel composition, diffrerent swelling behaviors are observed. As weight percent of acrylic acid increases, gels demonstrate higher swelling ratios in reverse osmosis water, but showed substantially decreased swelling when aqueous cations are present. Additionally, in multivalent cation solutions, overshoot peaks are present, whereby the gels have a peak swelling ratio but then deswell. Multivalent cations interact with deprotonated carboxylic acid groups, constricting the gel and expelling water. Mortar containing hydrogels showed reduced autogenous shrinkage and increased relative humidity.

Nanoclay filled hydrogels of poly (2-hydroxyethyl methacrylate-co-acrylamide) copolymers prepared by gamma radiation

International Nuclear Information System (INIS)

Rapado Paneque, M.; Matos Cause, W.; Barreras Gonzalez, G.; Griffith Perez, J.; Amalvy, J. I.; Van Espen, P.; Peniche, C.

2011-01-01

Hydrogels are polymers characterized by their ability to absorb a considerable amount of water. Hydrogels consist of polymer molecules physically or chemically crosslinked, forming a molecular network, so that in water they swell to an equilibrium value, preserving their shape [1]. The aim of this work was to prepare by gamma radiation poly (2-hydroxyethyl methacrylate-co-acrylamide) hydrogels, p(HEMA-co-AAm), doped with Nanoclay (laponite XLG). (Author)

Osteochondral defect repair using a polyvinyl alcohol-polyacrylic acid (PVA-PAAc) hydrogel.

Science.gov (United States)

Bichara, David A; Bodugoz-Sentruk, Hatice; Ling, Doris; Malchau, Erik; Bragdon, Charles R; Muratoglu, Orhun K

2014-08-01

Poly(vinyl alcohol) (PVA) hydrogels can be candidates for articular cartilage repair due to their high water content. We synthesized a PVA-poly(acrylic acid) (PAAc) hydrogel formulation and determined its ability to function as a treatment option for condylar osteochondral (OC) defects in a New Zealand white rabbit (NZWR) model for 12 weeks and 24 weeks. In addition to hydrogel OC implants, tensile bar-shaped hydrogels were also implanted subcutaneously to evaluate changes in mechanical properties as a function of in vivo duration. There were no statistically significant differences (p > 0.05) in the water content measured in the OC hydrogel implant that was harvested after 12 weeks and 24 weeks, and non-implanted controls. There were no statistically significant differences (p > 0.05) in the break stress, strain at break or modulus of the tensile bars either between groups. Histological analysis of the OC defect, synovial capsule and fibrous tissue around the tensile bars determined hydrogel biocompatibility. Twelve-week hydrogels were found to be in situ flush with the articular cartilage; meniscal tissue demonstrated an intact surface. Twenty-four week hydrogels protruded from the defect site due to lack of integration with subchondral tissue, causing fibrillation to the meniscal surface. Condylar micro-CT scans ruled out osteolysis and bone cysts of the subchondral bone, and no PVA-PAAc hydrogel contents were found in the synovial fluid. The PVA-PAAc hydrogel was determined to be fully biocompatible, maintained its properties over time, and performed well at the 12 week time point. Physical fixation of the PVA-PAAc hydrogel to the subchondral bone is required to ensure long-term performance of hydrogel plugs for OC defect repair.

pH responsive N-succinyl chitosan/Poly (acrylamide-co-acrylic acid hydrogels and in vitro release of 5-fluorouracil.

Directory of Open Access Journals (Sweden)

Shahid Bashir

Full Text Available There has been significant progress in the last few decades in addressing the biomedical applications of polymer hydrogels. Particularly, stimuli responsive hydrogels have been inspected as elegant drug delivery systems capable to deliver at the appropriate site of action within the specific time. The present work describes the synthesis of pH responsive semi-interpenetrating network (semi-IPN hydrogels of N-succinyl-chitosan (NSC via Schiff base mechanism using glutaraldehyde as a crosslinking agent and Poly (acrylamide-co-acrylic acid(Poly (AAm-co-AA was embedded within the N-succinyl chitosan network. The physico-chemical interactions were characterized by Fourier transform infrared (FTIR, X-ray diffraction (XRD, thermogravimetric analysis (TGA, and field emission scanning electron microscope (FESEM. The synthesized hydrogels constitute porous structure. The swelling ability was analyzed in physiological mediums of pH 7.4 and pH 1.2 at 37°C. Swelling properties of formulations with various amounts of NSC/ Poly (AAm-co-AA and crosslinking agent at pH 7.4 and pH 1.2 were investigated. Hydrogels showed higher swelling ratios at pH 7.4 while lower at pH 1.2. Swelling kinetics and diffusion parameters were also determined. Drug loading, encapsulation efficiency, and in vitro release of 5-fluorouracil (5-FU from the synthesized hydrogels were observed. In vitro release profile revealed the significant influence of pH, amount of NSC, Poly (AAm-co-AA, and crosslinking agent on the release of 5-FU. Accordingly, rapid and large release of drug was observed at pH 7.4 than at pH 1.2. The maximum encapsulation efficiency and release of 5-FU from SP2 were found to be 72.45% and 85.99%, respectively. Kinetics of drug release suggested controlled release mechanism of 5-FU is according to trend of non-Fickian. From the above results, it can be concluded that the synthesized hydrogels have capability to adapt their potential exploitation as targeted oral drug

PIXE investigation of in-vitro release of chloramphenicol across polyvinyl alcohol/ acrylamide hydrogel

International Nuclear Information System (INIS)

Rihawi, M.; Al-Zeer, A.; Allaf, A.

2012-01-01

Hydrogels based on polyvinyl alcohol (PVA) and different amounts of acrylamide monomer (AAm) were prepared by thermal crosslinking process in solid state. The PVA/AAm hydrogels were investigated for drug delivery system applications. Chloramphenicol was adopted as a model drug to study its release behaviour across the prepared hydrogels. Particle induced X-ray emission (PIXE) analytical technique was utilized to study the drug release behaviour across the hydrogels. A comparison study between PIXE and UV measurements was performed. FTIR measurements were carried out to perform the molecular characterization. The releasing behaviour of the drug across the hydrogels demonstrates a decrease and a subsequent increase in the drug release rate, as the AAm amount increases. The FTIR characterization of the prepared hydrogels has shown a competitive behaviour between the crosslinking of PVA with AAm monomer or oligomerized AAm, depending on the amount of AAm added to prepare the PVA/AAm hydrogels. (author)

21 CFR 173.5 - Acrylate-acrylamide resins.

Science.gov (United States)

2010-04-01

... produced by the polymerization of acrylamide with partial hydrolysis, or by copolymerization of acrylamide... polyacrylate-acrylamide resin is produced by the polymerization and subsequent hydrolysis of acrylonitrile in a... or cane sugar juice and liquor or corn starch hydrolyzate in an amount not to exceed 5 parts per...

Synthesis and toxicity of poly (2-hydroxyethyl methacrylate-co-acrylamide) hydrogels obtained by gamma photon irradiation

International Nuclear Information System (INIS)

Rapado, Manuel; Vernhes, Marioly; Peniche, Carlos

2016-01-01

In this paper is reported the obtaining of hydrogels from poly hydroxyethyl methacrylate-co-acrylamide, by simultaneous crosslinking copolymerization from corresponding monomers by gamma photon irradiation. The composition of network chains in the copolymer was estimated from elemental analysis and infrared spectroscopy. Additionally, the toxicity of these materials was tested finding the free acrylamide and biological assay SOS in bacteria. The extracts of washed matrices of copolymers showed low level of free acrylamide. Moreover, they were non toxic on the E. coli cells tested at any time. (author)

Synthesis and flocculation properties of gum ghatti andpoly(acrylamide-co-acrylonitrile) based biodegradable hydrogels

CSIR Research Space (South Africa)

Mittal, H

2014-12-01

Full Text Available This article reports the development of biodegradable flocculants based on graft co-polymers of gum ghatti (Gg) and a mixture of acrylamide and acrylonitrile co-monomers (AAm-co-AN). The hydrogel polymer exhibited an excellent swelling capacity...

Preparation and Study on Properties of Superabsorbent Hydrogel Composites of Acrylamide-Acrylic Acid and Zeolite in Agricultural Uses

Directory of Open Access Journals (Sweden)

Shohreh Vosuoghi

2017-11-01

Full Text Available Water shortage is one of the most important environmental problems in arid and semi-arid areas which cause complications in land vegetations. The use of superabsorbent hydrogel is one of the most vital methods, which helps to optimize agricultural irrigations. The purpose of this research is preparation and study on properties the superabsorbent hydrogels by copolymerization of acrylamide and acrylic acid monomers using zeolite as nanoclay particles (0, 0.05, 0.1, 0.15. The optimum amount of nanoparticles in relation to its effect on superabsorbent structure and properties, such as water absorbency, was investigated through designing experiments using FFD software. We used methylene bisacrylamide and ammonium ‌persulfate as crosslinker and initiator, respectively. Thermogravimetric analysis (TGA, Fourier transform spectroscopy (FTIR, scanning electron microscopy (SEM and X-ray diffractometry (XRD test results showed that the addition of nanoclay up to 0.1g caused improvement in the physical and chemical properties of superabsorbent such as thermal resistance, porous structure and uniform network structure. The superabsorbent hydrogel could absorb 1100 (g/g distilled water. The water absorption and water retention of superabsorbent were studied by loading it in 5 different soil texture classes which were 0:100, 25:75, 50:50, 75:25 and 100:0 mixture fractions of sand/loam soil. As a result, it was observed that in the first week after irrigation, the best retention of initial moisture belonged to the soil with 50% sand texture, and also the soil with sand texture returned to its initial weight after 53 days (i.e., 30 days later than the control sample.

Poly(acrylic acid)/polyethylene glycol hygrogel prepared by using gamma-ray irradiation for mucosa adhesion

Energy Technology Data Exchange (ETDEWEB)

Nho, Young-Chang; Park, Jong-Seok; Shin, Jung-Woong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Gwon, Hui-Jeong [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Khil, Myung-Seob [Chonbuk National University, Jeonju (Korea, Republic of); Lee, Deok-Won [Maxillofacial Surgery Dental Hospital, Seoul (Korea, Republic of); Ahn, Sung-Jun [JADAM Co., LTD., Seogwipo (Korea, Republic of)

2015-01-15

A buccal delivery system provides a much milder environment for drug delivery compared to an oral delivery which presents a hostile environment for drugs, especially proteins and polypeptides, owing to acid hydrolysis. Local delivery in an oral cavity has particular applications in the treatment of toothaches, periodontal disease, and bacterial infections. Poly(acrylic acid) (PAA)-based hydrogels prepared using a chemical initiator have been attempted for a mucoadhesive system owing to their flexibility and excellent bioadhesion. In this experiment, PAA and polyethylene glycol (PEG) were selected to prepare using a radiation process a bioadhesive hydrogel for adhesion to mucosal surfaces. PAA and PEG were dissolved in purified water to prepare a homogeneous PAA/PEG solution, and the solution was then irradiated using an electron beam at dose up to 70 kGy to make the hydrogels. Their physical properties, such as gel percent, swelling percent, and adhesive strength to mucosal surfaces, were investigated. In this experiment, various amounts of PEG were incorporated into the PAA to enhance the mucoadhesive property of the hydrogels. The effect of the molecular weight of PEG on the mucoadhesion was also examined.

Superabsorbent nanocomposite synthesis of cellulose from rice husk grafted poly(acrylate acid-co-acrylamide)/bentonite

Science.gov (United States)

Helmiyati; Abbas, G. H.; Kurniawan, S.

2017-04-01

Superabsorbent nanocomposite synthesis of cellulose rice husk as the backbone with free radical polymerization method in copolymerization grafted with acrylic acid and acrylamide monomer. The cellulose was isolated from rice husk with mixture of toluene and ethanol and then hemicellulose and lignin were removed by using potassium hydroxide 4% and hydrogen peroxide 2%. The obtained cellulose rendement was 37.85%. The functional group of lignin analyzed by FTIR spectra was disappeared at wavenumber 1724 cm-1. Crystal size of the obtained isolated cellulose analyzed by XRD diffraction pattern was 34.6 nm, indicated the nanocrystal structure. Copolymerization was performed at temperature of 70°C with flow nitrogen gas. Initiator and crosslinking agent used were potassium persulfate and N‧N-methylene-bis-acrylamide. The swelling capacity of water and urea showed the results was quite satisfactory, the maximum swelling capacity in urea and water were 611.700 g/g and 451.303 g/g, respectively, and can be applied in agriculture to absorb water and urea fertilizer.

Influence of different media on micromorphology of radiation synthesized poly(acrylamide-sodium acrylate) hydrogels

International Nuclear Information System (INIS)

Shan Jun; Chen Jie; Liu Zhanjun

1998-01-01

Poly(acrylamide-sodium acrylate) hydrogels were synthesized by 60 Co-γ ray radiation polymerization in aqueous solutions. The micromorphology of hydrogel samples dehydrated in the different alcohol media such as methanol, ethyl alcohol, n-propyl alcohol, iso-propyl alcohol, and tert-butyl alcohol was observed by scanning electron microscope (SEM). The critical concentrations at volume phase transition of the hydrogels in the different alcohol medium-water solutions were obtained. The results indicate that the hydrogel samples dehydrated in methanol and in ethyl alcohol display bubble-film network structures, and those in n-propyl alcohol and in iso-propyl alcohol and in tert-butyl alcohol demonstrate the porous structures including the dense phase. The reason is discussed from the critical concentrations and solubility parameters of different alcohol media. (author)

Radiation synthesis and characterization of new hydrogels based on acrylamide copolymers cross-linked with 1-allyl-2-thiourea

Energy Technology Data Exchange (ETDEWEB)

Sahiner, Nurettin [Department of Chemistry, Faculty of Science, Hacettepe University, Beytepe Campus, 0653 Ankara (Turkey); Malci, Savas [Department of Chemistry, Faculty of Science, Hacettepe University, Beytepe Campus, 0653 Ankara (Turkey); Celikbicak, Oemuer [Department of Chemistry, Faculty of Science, Hacettepe University, Beytepe Campus, 0653 Ankara (Turkey); Kantoglu, Oemer [Ankara Nuclear Research Center, Turkish Atomic Energy Authority, 06983 Ankara (Turkey); Salih, Bekir [Department of Chemistry, Faculty of Science, Hacettepe University, Beytepe Campus, 0653 Ankara (Turkey)]. E-mail: bekir@hacettepe.edu.tr

2005-10-01

Poly(acrylamide-1-allyl-2-thiourea) hydrogels, Poly(AA-AT), were synthesized by gamma irradiation using {sup 60}Co {gamma} source in different irradiation dose and at different 1-allyl-2-thiourea content in the monomer mixture. For the characterization of the hydrogels, Fourier transform infrared spectrometer (FT-IR), thermogravimetric analyzer (TGA), elemental analyzer and the swellability of the hydrogels were used. It was noted that 1-allyl-2-thiourea in the synthesized hydrogels was increased by the increasing the content of the 1-allyl-2-thiourea in the irradiation monomer mixture and increasing the radiation dose for the hydrogel synthesis. sis.

Studies on chemically crosslinkable carboxy terminated-poly(propylene fumarate-co-ethylene glycol)-acrylamide hydrogel as an injectable biomaterial

International Nuclear Information System (INIS)

Kallukalam, B C; Jayabalan, M; Sankar, V

2009-01-01

Carboxy terminated-poly(propylene fumarate)-co-ethylene glycol) (CT-PPF-co-PEG) was prepared and set into crosslinked hydrogel material with acrylamide. The setting studies reveal that this copolymer system can be used as an injectable material. The hydrogel material exhibits a higher degree of swelling, good mechanical strength and flexibility. The hydrogel favours adhesion of L929 fibroblast cells without proliferation on the surface. However, cardiac fibroblast cells (isolated from new born rat (Wistar) hearts) adhere and proliferate on the hydrogel due to the formation of synergistic hydrophilic-hydrophobic surface-by-surface reorganization.

Studies on chemically crosslinkable carboxy terminated-poly(propylene fumarate-co-ethylene glycol)-acrylamide hydrogel as an injectable biomaterial

Energy Technology Data Exchange (ETDEWEB)

Kallukalam, B C; Jayabalan, M [Polymer Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695 012 (India); Sankar, V, E-mail: muthujayabalan@rediffmail.co [Division of Cellular and Molecular Cardiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram 695 012 (India)

2009-02-15

Carboxy terminated-poly(propylene fumarate)-co-ethylene glycol) (CT-PPF-co-PEG) was prepared and set into crosslinked hydrogel material with acrylamide. The setting studies reveal that this copolymer system can be used as an injectable material. The hydrogel material exhibits a higher degree of swelling, good mechanical strength and flexibility. The hydrogel favours adhesion of L929 fibroblast cells without proliferation on the surface. However, cardiac fibroblast cells (isolated from new born rat (Wistar) hearts) adhere and proliferate on the hydrogel due to the formation of synergistic hydrophilic-hydrophobic surface-by-surface reorganization.

In-Vitro Release of Ketoprofen Behavior Loaded in Polyvinyl Alcohol / Acrylamide Hydrogels Prepared by Gamma Irradiation

International Nuclear Information System (INIS)

Mahmoud, Gh.A.; Hegazy, D.E.; Kamal, H.

2014-01-01

Hydrogels based on various ratios of polyvinyl alcohol (PVA) and acrylamide (AAm) were prepared by gamma radiation. The formed hydrogels were characterized by spectroscopic analysis (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and swelling studied. It was found that the thermal stability of the hydrogel decreases as the AAm content increases in the hydrogel. The higher the AAm content in the hydrogel, the lower the values of Tm and ΔH m . Ketoprofen was adopted as a model drug to study the adsorption and release behavior of (PVA/AAm) hydrogel. The drug adsorption was decreased by increasing AAm ratio in the hydrogel. From the in vitro drug release study in ph progressive media, the basic medium was showed comparatively the highest release and the (PVA/AAm) hydrogel of composition (70/30) was found to be the highest release one. The mechanism of Ketoprofen release from the (PVA/AAm) matrix was found to be non-Fickian mechanism for all investigated hydrogels at ph 7.

Immobilization of pH-sensitive CdTe Quantum Dots in a Poly(acrylate) Hydrogel for Microfluidic Applications

Science.gov (United States)

Franke, M.; Leubner, S.; Dubavik, A.; George, A.; Savchenko, T.; Pini, C.; Frank, P.; Melnikau, D.; Rakovich, Y.; Gaponik, N.; Eychmüller, A.; Richter, A.

2017-04-01

Microfluidic devices present the basis of modern life sciences and chemical information processing. To control the flow and to allow optical readout, a reliable sensor material that can be easily utilized for microfluidic systems is in demand. Here, we present a new optical readout system for pH sensing based on pH sensitive, photoluminescent glutathione capped cadmium telluride quantum dots that are covalently immobilized in a poly(acrylate) hydrogel. For an applicable pH sensing the generated hybrid material is integrated in a microfluidic sensor chip setup. The hybrid material not only allows in situ readout, but also possesses valve properties due to the swelling behavior of the poly(acrylate) hydrogel. In this work, the swelling property of the hybrid material is utilized in a microfluidic valve seat, where a valve opening process is demonstrated by a fluid flow change and in situ monitored by photoluminescence quenching. This discrete photoluminescence detection (ON/OFF) of the fluid flow change (OFF/ON) enables upcoming chemical information processing.

Sodium Carboxymethyl Cellulose Using Acrylamide and Acrylic Acid and Investigation of Drug Delivery Properties

Directory of Open Access Journals (Sweden)

Mahdi Geramipour

2016-07-01

Full Text Available Hydrogels are three-dimensional polymer networks that can absorb and retain a huge amount of aqueous fluids even under certain pressure, but do not dissolve in water. They are responsive to environmental stimulants such as pH and ionic strength of the solution. In this study, a series of novel sodium carboxymethyl cellulose-based hydrogel nanocomposites were synthesized using acrylamide comonomer in the presence of iron magnetic as crosslinker and acrylic acid ammonium persulfate (APS comonomer as initiator. All reaction variables affecting the water absorbency of the hydrogel nanocomposite including the concentration of crosslinking agent and initiator, and comonomers ratio were optimized in order to achieve the maximum absorption capacity. The experimental data showed that the hydrogel nanocomposite exhibited improved swelling capacity compared to the nanoparticel-free hydrogel. In addition, optimized hydrogel nanocomposite showed a good water uptake ability and the equilibrium swelling capacity was achieved within the initial 10 min. In examining the quality of the synthesized hydrogel nanocomposite, the amount of absorption in saline solutions of different concentrations was measured. Furthermore, the swelling behavior of hydrogel nanocomposite in solutions with different pH values was evaluated. The chemical structure of the hydrogel nanocomposites was characterized by means of transmission electron microscopy (TEM, scanning electron microscopy (SEM, vibrating sample magnetometry (VSM, thermogravimetry analysis (TGA, derivative thermogravimetry (DTG and Fourier transform infrared spectroscopy (FTIR. In order to study the drug delivery and drug release behavior, the release of sodium diclofenac as a model drug from synthesized hydrogel nanocomposite was examined in two acidic and basic buffer environments. The results indicated that this hydrogel nanocomposite may be an appropriate alternative for drug release processes in human body.

Synthesis and characterization of super absorbent poly (acrylamide-co-potassium acrylate) hydrogels by radiation technique

International Nuclear Information System (INIS)

Erizal

2010-01-01

A series of super absorbent hydrogels were prepared from acrylamide (AAm) and potassium acrylate (KA) by gamma irradiation technique at room temperature. The solution containing potassium acrylate 15% and different concentrations of AAm (10-16%) were irradiated by gamma rays (20-40 kGy). The hydrogels produced by irradiation were characterized by fourier transform infra red spectroscopy (FT-IR). The gel fraction, kinetics of swelling and the equilibrium degree of swelling (EDS) were studied. Under irradiation dose of 20 kGy and concentration of AAM 10 %), poly(AAm-co-KA) hydrogel with high gel fraction (99.08%) and very high EDS (420 g/g) were obtained. The capacity of hydrogel to adsorb metal ion Cu 2+ and Fe 3+ were investigated. It is shown than 10 minutes the hydrogel could adsorb Cu 2+ ion up to 95 %, and Fe 3+ ion up to 55 % in 80 minutes. This hydrogel has a potential to be used for soil conditioning and ion metal absorbent. (author)

The Influence of the Addition of Polyacrylic Hydrogel on the Content of Proteins, Minerals and Trace Elements in Milk Protein Solutions

Directory of Open Access Journals (Sweden)

Aleksandar Ž. Kostić

2014-01-01

Full Text Available Solutions of milk protein concentrate, whey protein concentrate and bovine serum albumin (BSA were treated with polyacrylic hydrogel to establish whether the hydrogel could be used for decontamination of heavy metal ions from milk protein-based products. The obtained results indicated that swelling of hydrogel in these solutions had different effects on their mineral, trace element and total protein content. Total protein and phosphorus content increased in milk protein concentrate and whey protein concentrate solutions after swelling of hydrogel without changes in their protein compositions. On the other hand, the protein content in BSA solution decreased after swelling. The content of Na did not change in milk protein concentrate solution, whereas it significantly increased in whey protein concentrate solution after hydrogel swelling. The content of Ca and Mg was reduced after the swelling in milk protein concentrate and whey protein concentrate solutions for 20.3–63.4 %, depending on the analysed sample and the mineral. The content of Zn did not change during swelling, whereas the content of Fe, Cu, Mn, Ni and Pb significantly decreased after hydrogel swelling in all analysed samples. According to the obtained results, the addition of polyacrylic hydrogel to milk and whey protein concentrate solutions can significantly decrease the content of heavy metal ions without affecting their protein composition. Therefore, this work could be useful in developing a new technological process for heavy metal purification of milk protein-based products.

Study of poly (acrylamide-co-2-acrylamido-2-methylpropane sulfonic acid) hydrogel using gamma radiation initiation

International Nuclear Information System (INIS)

Zhang, C.; Easteal, A.J.

1998-01-01

Full text: Poly (acrylamide-co-2-acrylamido-2-methylpropane sulfonic acid ) (PAAM-co-AMPS) polyelectrolyte hydrogels were formed by using γ-radiation to initiate polymerization and cross-linking. The dependence of chain growth and cross-linking of liquid-like gel on absorbed dose was observed by viscosity measurement. It was found that the viscosity of liquid-like gel increased non-linearly with increasing radiation dose. Crosslinking took place at about 2,300 Gy. It was noted that an ageing effect occurred, such that the viscosity of liquid-like gels decreased significantly on standing. X-ray diffraction revealed that after dehydration the dried gels were amorphous, suggesting that radiation polymerization occurs by random initiation and propagation. Differential scanning calorimetry (DSC) indicated a clear distinction between the thermal behaviour of the homopolymer gels formed by irradiation, and the behaviour of the copolymer gels. PAAM-co-AMPS gels have enhanced thermal stability in comparison to PAAM and PAMPS. The melting points of water in the gels initially increase with increasing dose, and decrease slightly at very high radiation dose. Those trends can be explained by the variation in the numbers of solute molecules or ions in the gels with absorbed dose. Melting points of water in gels can be used for observation of the polymerization process associated with irradiation. Copolymer composition (expressed by either f 1 (AAM molal fraction ) or f 2 (AMPS molal fraction) ) associated with radiation dose was determined by both elemental analysis and FTIR. Both methods show that f 1 increases to a maximum with increasing dose, and subsequently decreases. It is concluded that PAAM-co-AMPS hydrogels were synthesised successfully by gamma radiation initiation, and that copolymer compositions are dependent on radiation dose

Evaluation of CO2-based cold sterilization of a model hydrogel.

Science.gov (United States)

Jiménez, A; Zhang, J; Matthews, M A

2008-12-15

The purpose of the present work is to evaluate a novel CO(2)-based cold sterilization process in terms of both its killing efficiency and its effects on the physical properties of a model hydrogel, poly(acrylic acid-co-acrylamide) potassium salt. Suspensions of Staphylococcus aureus and Escherichia coli were prepared for hydration and inoculation of the gel. The hydrogels were treated with supercritical CO(2) (40 degrees C, 27.6 MPa). The amount of bacteria was quantified before and after treatment. With pure CO(2), complete killing of S. aureus and E. coli was achieved for treatment times as low as 60 min. After treatment with CO(2) plus trace amounts of H(2)O(2) at the same experimental conditions, complete bacteria kill was also achieved. For times less than 30 min, incomplete kill was noted. Several physical properties of the gel were evaluated before and after SC-CO(2) treatment. These were largely unaffected by the CO(2) process. Drying curves showed no significant change between treated (pure CO(2) and CO(2) plus 30% H(2)O(2)) and untreated samples. The average equilibrium swelling ratios were also very similar. No changes in the dry hydrogel particle structure were evident from SEM micrographs.

Effect of Maleic Acid Content on the Thermal Stability, Swelling Behaviour and Network Structure of Gelatin -Based Hydrogels Prepared by Gamma Irradiation

International Nuclear Information System (INIS)

Eid, M.; Dessouki, A.M.; Abdel-Ghaffar, M.A.

2005-01-01

The preparation of highly swelling hydrogels containing diprotic acid and gelatin carried out by gamma-irradiation of acrylamide/maleic acid/gelatine/water mixture at ambient temperature. Poly (acrylamide/maleic acid/gelatin) p(AAm/MA/G) hydrogels were prepared in different MA and G contents at low dose rate (0.94 kGy/h), and moderate dose rate (3.84 kGy/h). The prepared hydrogels were confirmed by FT1R . The effect of copolymer composition, dose and dose rate on the swelling behaviour and the type of water diffusion in the network structure of the hydrogels was discussed. Increasing of MA content and G in the initial mixture leads to an increase in the amount of MA and G in the gel system and decrease in the gelation percent. The swelling behaviours of the hydrogel prepared at moderate dose rate increased with increasing MA mole content in the gel system. On the other hand, no systematic dependence of swelling on MA content was observed for the hydrogels obtained at low dose rate. Pore structure of the hydrogels was monitored by using scanning electron microscopy. Systematic swelling of P(AAm/MA/G) hydrogels prepared at moderate dose rates can be explained by the homogeneous pore size distribution of network. Thermogravimetric analysis (TGA) was employed to study the effect of network structure formation on the thermal behavior of the copolymer. To give a better understanding of the thermal stability of polymers, the rate of the thermal decomposition of P(AAm/MA/G) hydrogels has been evaluated

Effect of crosslinker length on the elastic and compression modulus of poly(acrylamide) nanocomposite hydrogels

International Nuclear Information System (INIS)

Zaragoza, J; Chang, A; Asuri, P

2017-01-01

Polymer hydrogelshave shown to exhibit improved properties upon the addition of nanoparticles; however, the mechanical underpinnings behind these enhancements have not been fully elucidated. Moreover, fewer studies have focused on developing an understanding of how polymer parameters affect the nanoparticle-mediated enhancements. In this study, we investigated the elastic properties of silica nanoparticle-reinforced poly(acrylamide) hydrogels synthesized using crosslinkers of various lengths. Crosslinker length positively affected the mechanical properties of hydrogels that were synthesized with or without nanoparticles. However the degree of nanoparticle enhancement was negatively correlated to crosslinker length. Our findings enable the understanding of the respective roles of nanoparticle and polymer properties on nanoparticle-mediated enhancement of hydrogels and thereby the development of next-generation nanocomposite materials. (paper)

Influence of the ionic character of a drug on its release rate from hydrogels based on 2-hydroxyethylmethacrylate and acrylamide synthesized by photopolymerization

Directory of Open Access Journals (Sweden)

M. L. Gomez

2012-03-01

Full Text Available The influence of the ionic character of a specific drug on its release rate from a hydrogel based on 2-hydroxyethylmethacrylate (HEMA and acrylamide (AAm is analyzed. The hydrogel was synthesized by photopolymerization employing visible light, safranine O (Saf, as sensitizer, and a silsesquioxane functionalized with amine and methacrylate groups (SFMA, as co-initiator and crosslinker. Safranine O (Saf was employed as a model of a cationic drug and the anionic form of resorufin (Rf as a model of an anionic drug. Saf exhibited a larger affinity with functional groups of the hydrogel than that of Rf. This produced a lower loading and a faster release rate of Rf with respect to Saf. Besides, the release rate of Rf followed a Fickian behavior, while that of Saf exhibited a non-Fickian behavior. By hydrolyzing the hydrogel at pH = 13, amide groups supplied by AAm were irreversibly converted into carboxylic acid groups. Higher loadings and slower release rates of Saf from the hydrolyzed hydrogels were observed, making them particularly suitable for the slow drug-delivery of cationic drugs.

Synthesis of superabsorbent hydrogel by radiation crosslinking of acrylic acid, semi-refined kappa-carrageenan and sugarcane bagasse blend

International Nuclear Information System (INIS)

Jizmundo, Leonie-Lou Dominguez

2015-04-01

Superabsorbent hydrogels have three-dimensional networks that enable it to exhibit great water absorption capacity leading to its promising applications. However, existing commercial hydrogels are mainly acrylic acid which causes environmental problems. In this study, the incorporation of agricultural waste as filler and polysaccharide from natural sources as binder for the production of superabsorbent hydrogel was done to reduce the use of acrylic acid as well as its environmental impact while adding value to the incorporated materials. A series of superabsorbent hydrogel with the blend of acrylic acid, semi-refined kappa carrageenan and sugarcane bagasse were synthesized by radiation crosslinking. The gel fraction and swelling capacity of the hydrogels were determined and studied. The characterizations were facilitated by Fourier transform infrared spectroscopy technique (FTIR) and Thermogravimetric Analysis (TGA). In the results obtained from analyses, the characteristic peaks of acrylic acid and sugarcane bagasse were observed in the FTIR spectra and the three step peaks if synthesized hydrogel in its TGA implies an improvement in thermal stability of the product. The synthesized superabsorbent hydrogel blends had exhibited comparable gel fraction to that of the polyacrylic acid hydrogel, had great swelling capacity, and achieved equilibrium degree of swelling within 72-96 hours. The optimum synthesized superabsorbent hydrogel is 3% semi-refined kappa-carrageenan, 3% sugarcane bagasse, 15% acrylic acid neutralize up to 50% and irradiated at 15kGy dose which exhibited a swelling of 599.53 and gel fraction of 39.73. (author)

Experimental Investigation of Mechanical and Thermal Properties of Silica Nanoparticle-Reinforced Poly(acrylamide) Nanocomposite Hydrogels.

Science.gov (United States)

Zaragoza, Josergio; Babhadiashar, Nasim; O'Brien, Victor; Chang, Andrew; Blanco, Matthew; Zabalegui, Aitor; Lee, Hohyun; Asuri, Prashanth

2015-01-01

Current studies investigating properties of nanoparticle-reinforced polymers have shown that nanocomposites often exhibit improved properties compared to neat polymers. However, over two decades of research, using both experimental studies and modeling analyses, has not fully elucidated the mechanistic underpinnings behind these enhancements. Moreover, few studies have focused on developing an understanding among two or more polymer properties affected by incorporation of nanomaterials. In our study, we investigated the elastic and thermal properties of poly(acrylamide) hydrogels containing silica nanoparticles. Both nanoparticle concentration and size affected hydrogel properties, with similar trends in enhancements observed for elastic modulus and thermal diffusivity. We also observed significantly lower swellability for hydrogel nanocomposites relative to neat hydrogels, consistent with previous work suggesting that nanoparticles can mediate pseudo crosslinking within polymer networks. Collectively, these results indicate the ability to develop next-generation composite materials with enhanced mechanical and thermal properties by increasing the average crosslinking density using nanoparticles.

Biomimetic hydrogel materials

Science.gov (United States)

Bertozzi, Carolyn; Mukkamala, Ravindranath; Chen, Qing; Hu, Hopin; Baude, Dominique

2000-01-01

Novel biomimetic hydrogel materials and methods for their preparation. Hydrogels containing acrylamide-functionalized carbohydrate, sulfoxide, sulfide or sulfone copolymerized with a hydrophilic or hydrophobic copolymerizing material selected from the group consisting of an acrylamide, methacrylamide, acrylate, methacrylate, vinyl and a derivative thereof present in concentration from about 1 to about 99 wt %. and methods for their preparation. The method of use of the new hydrogels for fabrication of soft contact lenses and biomedical implants.

Economic benefit of a polyacrylate-based hydrogel compared to an amorphous hydrogel in wound bed preparation of venous leg ulcers

Directory of Open Access Journals (Sweden)

Kaspar D

2015-04-01

Full Text Available Daniela Kaspar,1 Jörg Linder,1 Petra Zöllner,1 Ulrich Simon,2 Hans Smola1,31Medical Competence Centre, Paul Hartmann AG, Heidenheim, Germany; 2Scientific Computing Centre, Ulm University, Ulm, Germany; 3Department of Dermatology, University of Cologne, Cologne, GermanyObjective: To assess the cost-effectiveness of a polyacrylate (PA-based hydrogel compared to an amorphous hydrogel in wound bed preparation for venous leg ulcers.Method: A cost-effectiveness analysis was undertaken alongside a multicenter, randomized controlled trial performed in France. A total of 75 patients with venous leg ulcers extensively covered with fibrin and necrotic tissue were randomized to a PA-containing hydrogel or an amorphous hydrogel. Wounds were treated for 14 days and costs were estimated from the German payer's perspective. Medical costs included study treatment, wound treatment supply, and labor time. The clinical benefit was expressed as the number of patients with wounds >50% covered with granulation tissue within 14 days. The incremental cost-effectiveness ratio (ICER was expressed as the additional cost spent with >50% granulation tissue per day per patient within 14 days of leg ulcer care.Results: Because of individual pricing of wound dressings in hospitals, cost data were derived from the outpatient sector. A total of 33 patients were treated using the PA-based hydrogel and 37 patients using the amorphous hydrogel. The estimated total direct costs per patient and per 14 days of therapy were €306 for both treatment groups. However, with the PA-based hydrogel, 2.5 additional days with wounds covered >50% with granulation tissues were gained within 14 days of leg ulcer care compared to the comparator. The ICER was €0 per additional day spent with >50% granulation tissue.Conclusion: Although there were a greater number of dressing changes in the PA-based hydrogel treatment, the total treatment cost for 14 days of leg ulcer care was the same for both

Thermosensitive copolymeric hydrogels with the regulated temperature of a phase transition

International Nuclear Information System (INIS)

Samchenko, Yu.M.; Konovalova, V.V.; Korotich, E.I.; Poltoratskaya, T.P.; Pobegaj, A.A.; Burban, A.F.; Ul'berg, Z.R.; Samchenko, Yu.M.; Konovalova, V.V.; Korotich, E.I.; Poltoratskaya, T.P.; Pobegaj, A.A.; Burban, A.F.; Ul'berg, Z.R.

2011-01-01

The work is devoted to the methods of obtaining the thermosensitive copolymeric hydrogels based on the NIPAAm with acrylic acid and its derivatives such as acrylamide, acrylonitrile, and methylacrylate. The mechanisms of thermoinitiated phase transitions in hydrogel matrices and the regularities of the thermoinitiated release of model compounds and drugs (aniline, novocaine, and sodium diclofenac) from copolymeric hydrogel are investigated.

Interaction of neptunium(V) with polyacrylic acid

International Nuclear Information System (INIS)

Kubota, Takumi; Tochiyama, Osamu; Yamazaki, Hiromichi; Sato, Nobuharu

1996-01-01

For the quantitative description of the interaction of actinoids with humic substances, it is necessary to clarify the effects of both polyelectrolyte and heterogeneous nature of humic substances. To estimate these effects separately, polyacrylic acid has been selected as representative of well-defined, homogenous polymeric weak acids, and its interaction with Np(V) has been investigated by a solvent extraction method. By expressing the effective concentration of the complexing ligand by the concentration of ionized carboxylate groups, the apparent complex formation constant has been obtained at several pH, ionic strength and average molecular weights. The results indicated that the apparent complex formation constant varied with the degree of ionization(α) of polyacrylic acid and that the manner of variation resembled that of its apparent proton association constant. (author)

Mechano-responsive hydrogels crosslinked by reactive block copolymer micelles

Science.gov (United States)

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

Improvement in the water retention characteristics of sandy loam soil using a newly synthesized poly(acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite material.

Science.gov (United States)

Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

2012-08-03

The use of some novel and efficient crop nutrient-based superabsorbent hydrogel nanocomposites (SHNCs), is currently becoming increasingly important to improve the crop yield and productivity, due to their water retention properties. In the present study a poly(Acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite was synthesized and its physical properties characterized using Energy Dispersive X-ray (EDX), FE-SEM and FTIR spectroscopic techniques. The effects of different levels of SHNC were studied to evaluate the moisture retention properties of sandy loam soil (sand 59%, silt 21%, clay 19%, pH 7.4, EC 1.92 dS/m). The soil amendment with 0.1, 0.2, 0.3 and 0.4 w/w% of SHNC enhanced the moisture retention significantly at field capacity compared to the untreated soil. Besides, in a separate experiment, seed germination and seedling growth of wheat was found to be notably improved with the application of SHNC. A delay in wilting of seedlings by 5-8 days was observed for SHNC-amended soil, thereby improving wheat plant growth and establishment.

Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

International Nuclear Information System (INIS)

Lim, Lim Sze; Ahmad, Ishak; Lazim, Mohd Azwani Shah Mat; Amin, Mohd. Cairul Iqbal Mohd

2014-01-01

The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier

Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

Energy Technology Data Exchange (ETDEWEB)

Lim, Lim Sze; Ahmad, Ishak; Lazim, Mohd Azwani Shah Mat [Faculty of Science and Technology, University Kebangsaan Malaysia, 43600 UKM, Bangi, Selangor (Malaysia); Amin, Mohd. Cairul Iqbal Mohd [Faculty of Pharmacy, University Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur (Malaysia)

2014-09-03

The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier.

Radiation synthesis and characterization of pH-sensitive poly(acrylic acid-co-N-vinyl-2-pyrrolidone) hydrogels

International Nuclear Information System (INIS)

Yang Mingcheng; Zhu Jun; Song Weidong; Song Hongyan; Zhu Chengshen

2006-01-01

Hydrogels are crosslinked, three-dimensional hydrophilic polymer networks that swell but do not dissolve when brought into contact with water. These materials have been investigated extensively for potential applications in the biomedical field because of their similarities to soft tissues and their good tissue and blood compatibility. More specifically, pH-sensitive hydrogels are used for sustained gastro-intestinal drug delivery systems due to the intimacy and extended duration of contact. In this work, pH-sensitive copolymer hydrogels were prepared using acrylic acid and N-vinyl-2-pyrrolidone by γ-ray irradiation at ambient temperature. Effects of dose, monomer concentration, monomer composition, temperature and pH on the swelling ratio (SR) of the copolymer hydrogels were investigated in detail. The results show that SR of the copolymer hydrogels decreases with the monomer concentration and with the increase of absorbed dose. These copolymer hydrogels show good pH-sensitive behavior. These material shows no noticeable change in swelling at lower pH (pH<4) but an abrupt increase in swelling at higher pH (from pH7 to pH9.8). At pH 1.4, the SR of the copolymer hydrogels increases with the temperature. To the contrary, at pH 9.8, the SR of the copolymer hydrogels decreases with the temperature. (authors)

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...

Synthesis and application of intelligent hydrogels

International Nuclear Information System (INIS)

Kaetsu, I.; Uchida, K.; Sutani, K.; Nakayama, H.; Tamori, A.

2000-01-01

The authors have studied synthesis and application of stimule-sensitive and responsive hydrogels. In this report, two kinds of investigations were carried out on the intelligent hydrogels and the applications with radiation techniques. 1. Synthesis of temperature responsive sol-gel transition polymer and the application to drug delivery systems. Polysopropyl acrylamide is a typical temperature responsive polymers and the copolymers show broad variation of LCST (sol-gel transition temperature). The various copolymers of isopropyl acrylamide were synthesized by UV or radiation. 2. Surface curing of pH and electric field responsive hydrogel and the application to drug delivery systems. Electrolyte monomers such as acrylic acid was coated on the surface of polymer membrane (porous or non-porous) including drugs, and cured by UV or radiation various enzymes were immobilized in the coating layer in many cases. The product showed pH, electro-field and substrate responsive releases of model drug under on-off switching of environmental conditions. (J.P.N.)

Synthesis and application of intelligent hydrogels

Energy Technology Data Exchange (ETDEWEB)

Kaetsu, I.; Uchida, K.; Sutani, K.; Nakayama, H.; Tamori, A. [Kinki Univ., Higashi-Osaka, Osaka (Japan). Faculty of Science and Technology

2000-03-01

The authors have studied synthesis and application of stimule-sensitive and responsive hydrogels. In this report, two kinds of investigations were carried out on the intelligent hydrogels and the applications with radiation techniques. 1. Synthesis of temperature responsive sol-gel transition polymer and the application to drug delivery systems. Polysopropyl acrylamide is a typical temperature responsive polymers and the copolymers show broad variation of LCST (sol-gel transition temperature). The various copolymers of isopropyl acrylamide were synthesized by UV or radiation. 2. Surface curing of pH and electric field responsive hydrogel and the application to drug delivery systems. Electrolyte monomers such as acrylic acid was coated on the surface of polymer membrane (porous or non-porous) including drugs, and cured by UV or radiation various enzymes were immobilized in the coating layer in many cases. The product showed pH, electro-field and substrate responsive releases of model drug under on-off switching of environmental conditions. (J.P.N.)

Brittle and ductile adjustable cement derived from calcium phosphate cement/polyacrylic acid composites.

Science.gov (United States)

Chen, Wen-Cheng; Ju, Chien-Ping; Wang, Jen-Chyan; Hung, Chun-Cheng; Chern Lin, Jiin-Huey

2008-12-01

Bone filler has been used over the years in dental and biomedical applications. The present work is to characterize a non-dispersive, fast setting, modulus adjustable, high bioresorbable composite bone cement derived from calcium phosphate-based cement combined with polymer and binding agents. This cement, we hope, will not swell in simulated body fluid and keep the osteogenetic properties of the dry bone and avoid its disadvantages of being brittle. We developed a calcium phosphate cement (CPC) of tetracalcium phosphate/dicalcium phosphate anhydrous (TTCP/DCPA)-polyacrylic acid with tartaric acid, calcium fluoride additives and phosphate hardening solution. The results show that while composite, the hard-brittle properties of 25wt% polyacrylic acid are proportional to CPC and mixing with additives is the same as those of the CPC without polyacrylic acid added. With an increase of polyacrylic acid/CPC ratio, the 67wt% samples revealed ductile-tough properties and 100wt% samples kept ductile or elastic properties after 24h of immersion. The modulus range of this development was from 200 to 2600MPa after getting immersed in simulated body fluid for 24h. The TTCP/DCPA-polyacrylic acid based CPC demonstrates adjustable brittle/ductile strength during setting and after immersion, and the final reaction products consist of high bioresorbable monetite/brushite/calcium fluoride composite with polyacrylic acid.

Current state and future prospect on polyacrylic scid based superabsorbent polymer. Polyacrylic sankei kokyusuisei polymer no genjo to kongo no tenkai

Energy Technology Data Exchange (ETDEWEB)

Shimomura, T.; Kobayashi, H. (Nippon Shokubai Kagaku Kogyo Co. Ltd., Osaka (Japan))

1991-10-01

A polymer that absorbs water vigorously and swells is called a superabsorbent polymer (SAP). This peculiar character has developed diverse applications including paper diapers, and its production showed a rapid growth to more than 200,000 tons (worldwide) in the past decade. This paper introduces the development and applications for polyacrylic acid-based SAP, a representative SAP. The research began in the U.S.A. in about the year 1976. For its characteristics suitable for paper diapers and cost advantages, the acrylate-based SAP has become accounting for the most at the present. The polymer is manufactured by polymerzation crosslinking of acrylic acid or sodium acrylate to produce polyacrylate crosslinked bodies. The polymer swells to 100 to 1000 times in deionized water, and turns into a hydrogel. Unlike a sponge, the swelled gel will not ooze out water even if pressed. However, its absorption performance decreases extremely in electrolytic aqueous solution, which is a problem for the future development. 17 refs., 5 figs., 7 tabs.

Direct Synthesis of Hyperbranched Poly(acrylic acid-co-3-hydroxypropionate

Directory of Open Access Journals (Sweden)

Efkan Çatıker

2015-01-01

Full Text Available Hyperbranched poly(acrylic acid-co-3-hydroxypropionate (PAcHP was synthesized by base-catalyzed hydrogen transfer polymerization of acrylic acid through one step. The copolymers obtained through solution and bulk polymerization were insoluble in water and all organic solvents tried. Structural and compositional characterizations of hyperbranched PAcHP were performed by using FTIR, solid 13C-NMR, TGA, and titrimetric analysis. Acrylate fraction of the hyperbranched PAcHP obtained via bulk polymerization was determined as 60–65% by comparing TGA curves of hyperbranched PAcHP and pure poly(3-hydroxy propionate (PHP. However, analytical titration of the same sample revealed that acrylic acid units were about 47.3%. The results obtained from TGA and analytical titration were used to evaluate the chemical structure of the copolymer. Hyperbranched PAcHP exhibited hydrogel properties. Swelling behavior of the copolymer was investigated at a wide pH range and ionic strength. The dynamic swelling profiles of hyperbranched PAcHP exhibited a fast swelling behavior in the first hour and achieved the equilibrium state within 12 h in PBS. Depending on the conditions, the copolymers exhibited swelling ratios up to 2100%. As the copolymer has easily biodegradable propionate and versatile functional acrylic acid units, it can be used as not only biodegradable material in medical applications but also raw material in personal care commodities.

Armored Urease: Enzyme-Bioconjugated Poly(acrylamide) Hydrogel as a Storage and Sensing Platform.

Science.gov (United States)

Kunduru, Konda R; Kutcherlapati, S N Raju; Arunbabu, Dhamodaran; Jana, Tushar

2017-01-01

Jack bean urease is an important enzyme not only because of its numerous uses in medical and other fields but also because of its historical significance-the first enzyme to be crystallized and also the first nickel metalloenzyme. This enzyme hydrolyzes urea into ammonia and carbon dioxide; however, the stability of this enzyme at ambient temperature is a bottleneck for its applicability. To improve urease stability, it was immobilized on different substrates, particularly on polymeric hydrogels. In this study, the enzyme was coupled covalently with poly(acrylamide) hydrogel with an yield of 18μmol/cm 3 . The hydrogel served as the nanoarmor and protected the enzyme against denaturation. The enzyme immobilized on the polymer hydrogel showed no loss in activity for more than 30 days at ambient temperature, whereas free enzyme lost its activity within a couple of hours. The Michaelis-Menten constant (K m ) for free and immobilized urease were 0.0256 and 0.2589mM, respectively, on the first day of the study. The K m of the immobilized enzyme was approximately 10 times higher than that of the free enzyme. The hydrogel technique was also used to prepare light diffracting polymerized colloidal crystal array in which urease enzyme was covalently immobilized. This system was applied for the detection of mercury (Hg 2+ ) with the lower limit as 1ppb, which is below the maximum contaminant limit (2ppb) for mercury ions in water. The experimental details of these studies are presented in this chapter. © 2017 Elsevier Inc. All rights reserved.

Synthesis and characterization of poly(acrylic acid)-g-sodium alginate hydrogel initiated by gamma irradiation for controlled release of chlortetracycline HCl

International Nuclear Information System (INIS)

Mohamed, S.F.; Mahmoud, G.A.; Taleb, M.F.A.

2013-01-01

pH-Sensitive hydrogel was synthesized by gamma radiation crosslinking for sodium alginate extracted from the marine brown alga Turbinaria decurrens and acrylic acid. Preparation of the hydrogels involved free radical polymerization of a combination of acrylic acid (w = 0.2) and different contents of sodium alginate (w = 0.05, 0.10, and 0.15) in aqueous solution using gamma rays of a 60 Co source at an irradiation dose rate of 1.2 kGy/h. The swelling behavior of the prepared hydrogel was determined by investigating the swelling time, pH of medium, and alginate content in the hydrogel. The results showed that the hydrogel reached the equilibrium swelling state in water after 6 h. The hydrogel was found to be pH responsive. The drug loading and in vitro release properties of the hydrogel were also evaluated using chlortetracycline hydrochloride as the model drug. The adsorption isotherm studies by batching techniques under the effect of different initial feed concentrations of drug, different pH values, and different sodium alginate content of the adsorbent hydrogel were investigated. The diffusion of chlortetracycline hydrochloride within the hydrogel was found to be of non-Fickian character. The kinetic parameters such as the diffusion exponent, diffusion constant, and diffusion coefficient were also evaluated. (author)

Separation of water and oil by poly (acrylic acid)-coated stainless steel mesh prepared by radiation crosslinking

Energy Technology Data Exchange (ETDEWEB)

Nho, Young Chang; Shin, Jung Woong; Park, Jong Seok; Lim, Young Mook; Jeun, Joon Pyo; Kang, Phil Hyun [Research Division for Industry and Environment, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

2015-05-15

The stainless steel mesh coated with poly(acrylic acid) hydrogel was fabricated and applied for the separation of water and oil. The stainless steel mesh was immersed in aqueous poly (acrylic acid) solution, and then irradiated by radiation to introduce poly(acrylic acid) hydrogel on the surface of mesh by crosslinking. It was possible to separate oil and water from mixtures of oil/water effectively using the hydrogel-coated mesh. The effect of irradiation dose, coating thickness, size of mesh on the separation efficiency was examined.

Structure of polyacrylic acid and polymethacrylic acid solutions: a small angle neutron scattering study

Energy Technology Data Exchange (ETDEWEB)

Moussaid, A. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France)); Schosseler, F. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France)); Munch, J.P. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France)); Candau, S.J. (Lab. d' Ultrasons et de Dynamique des Fluides Complexes, Univ. Louis Pasteur, 67 - Strasbourg (France))

1993-04-01

The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiments. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to the experimental data. For a narrow range of ionization degrees nearly quantitative agreement with the theory is found for the polyacrylic acid system. (orig.).

Structure of polyacrylic acid and polymethacrylic acid solutions : a small angle neutron scattering study

Science.gov (United States)

Moussaid, A.; Schosseler, F.; Munch, J. P.; Candau, S. J.

1993-04-01

The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiemnts. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to the experimental data. For a narrow range of ionizaiton degrees nearly quantitative agreement with the theory is found for the polyacrylic acide system.

Complex formation of calcium with humic acid and polyacrylic acid

Energy Technology Data Exchange (ETDEWEB)

Kirishima, A.; Tanaka, K.; Niibori, Y.; Tochiyama, O. [Dept. of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku Univ., Sendai (Japan)

2002-07-01

In order to understand the migration behavior of radionuclides in the underground, it is also important to estimate the effect of the competing cations originally present in the groundwater. In this connection, the complexation of Ca(II) with Aldrich humic acid has been examined. For the study at trace concentrations ({proportional_to} 10{sup -10} M) of Ca(II), the solvent extraction of {sup 45}Ca with TTA and TOPO in cyclohexane has been used. At macro concentrations (10{sup -4} M) of Ca(II), the measurement of the free Ca{sup 2+} ion concentration with a calcium selective electrode has been conducted. To estimate the polyelectrolyte effect of humic acid separately from its heterogeneous composition effect, polyacrylic acid ([-CH{sub 2}CH(COOH)-]{sub n}) has been selected as a representative of the homogeneous polymeric weak acids and its complexation with Ca(II) has also been examined. The values of log {beta}{sub {alpha}} have been obtained at pH 5 {proportional_to} 7 in 0.1, 0.4 and 1.0 M NaCl, where {beta}{sub {alpha}} is the apparent formation constants defined by {beta}{sub {alpha}} = [ML]/([M][R]). In this definition, [ML] and [M] are the concentrations of bound and free Ca{sup 2+} respectively, [R] is the concentration of dissociated proton exchanging sites. log {beta}{sub {alpha}} of humate decreases from 2.19 {proportional_to} 2.92 (depending on pH and ionic strength 1.0 < I < 0.4) at pCa = 10 to 1.98 {proportional_to} 2.44 at pCa = 4, while the variation of pCa has no appreciable influence on the log {beta}{sub {alpha}} of polyacrylate (1.36 {proportional_to} 3.24 for I = 0.1 {proportional_to} 1.0). For both humate and polyacrylate, log {beta}{sub {alpha}} decreases linearly with log[Na{sup +}], where [Na{sup +}] is the bulk concentration of sodium ion. Their dependences of log {beta}{sub {alpha}} on ionic strength are stronger than those of log {beta} of monomeric carboxylates such as oxalate and EDTA, indicating the large electrostatic effect of

Ion-recognizable hydrogels for efficient removal of cesium ions from aqueous environment

Energy Technology Data Exchange (ETDEWEB)

Yu, Hai-Rong [School of Chemical Engineering, Sichuan University, No. 24, Southern 1 Section, Yihuan Road, Chengdu, Sichuan, 610065 (China); College of Chemistry and Environment Protection Engineering, Southwest University for Nationalities, No. 16, Southern 4 Section, Yihuan Road, Chengdu, Sichuan, 610041 (China); Hu, Jia-Qi [School of Chemical Engineering, Sichuan University, No. 24, Southern 1 Section, Yihuan Road, Chengdu, Sichuan, 610065 (China); Liu, Zhuang, E-mail: liuz@scu.edu.cn [School of Chemical Engineering, Sichuan University, No. 24, Southern 1 Section, Yihuan Road, Chengdu, Sichuan, 610065 (China); Ju, Xiao-Jie; Xie, Rui; Wang, Wei [School of Chemical Engineering, Sichuan University, No. 24, Southern 1 Section, Yihuan Road, Chengdu, Sichuan, 610065 (China); State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065 (China); Chu, Liang-Yin, E-mail: chuly@scu.edu.cn [School of Chemical Engineering, Sichuan University, No. 24, Southern 1 Section, Yihuan Road, Chengdu, Sichuan, 610065 (China); State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065 (China); Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing, Jiangsu 211816 (China)

2017-02-05

Highlights: • An easy-to-get and low-cost Cs{sup +}-recognizable polymeric hydrogel has been developed. • The hydrogel displays rapid and selective adsorption towards Cs{sup +}. • Synergistic effect of AAc units and Cs{sup +}(B18C6){sub 2} host-guest complexes is good for adsorption. • The hydrogel shows great potential for decontamination of Cs{sup +} from radioactive contaminants. - Abstract: At present, selective and efficient removal of cesium ions (Cs{sup +}) from nuclear waste is of significant importance but still challenging. In this study, an easy-to-get and low-cost hydrogel adsorbent has been developed for effective adsorption and removal of Cs{sup +} from aqueous environment. The novel Cs{sup +}-recognizable poly(acrylic acid-co-benzo-18-crown-6-acrylamide) (poly(AAc-co-B18C6Am)) hydrogel is specifically designed with a synergistic effect, in which the AAc units are designed to attract Cs{sup +} via electrostatic attraction and the B18C6Am units are designed to capture the attracted Cs{sup +} by forming stable 2:1 “sandwich” complexes. The poly(AAc-co-B18C6Am) hydrogels are simply synthesized by thermally initiated free-radical copolymerization and display excellent Cs{sup +} adsorption from commonly coexisting metal ions. Important parameters affecting the adsorption are investigated comprehensively, and the adsorption kinetics and adsorption isotherms are also discussed systematically. The poly(AAc-co-B18C6Am) hydrogels exhibit rapid Cs{sup +} adsorption within 30 min and the adsorption process is governed by the pseudo-second order model. Adsorption isotherm results demonstrate that the equilibrium data are well fitted by the Langmuir isotherm model, indicating that the Cs{sup +} adsorption is probably a monolayer adsorption process. Such Cs{sup +}-recognizable hydrogel materials based on the host-guest complexation are promising as efficient and feasible candidates for adsorption and removal of radioactive Cs{sup +} from nuclear

What makes lithium substituted polyacrylic acid a better binder than polyacrylic acid for silicon-graphite composite anodes?

Science.gov (United States)

Hays, Kevin A.; Ruther, Rose E.; Kukay, Alexander J.; Cao, Pengfei; Saito, Tomonori; Wood, David L.; Li, Jianlin

2018-04-01

Lithium substituted polyacrylic acid (LiPAA) has previously been demonstrated as a superior binder over polyacrylic acid (PAA) for Si anodes, but from where does this enhanced performance arise? In this study, full cells are assembled with PAA and LiPAA based Si-graphite composite anodes that dried at temperatures from 100 °C to 200 °C. The performance of full cells containing PAA based Si-graphite anodes largely depend on the secondary drying temperature, as decomposition of the binder is correlated to increased electrode moisture and a rise in cell impedance. Full cells containing LiPAA based Si-graphite composite electrodes display better Coulombic efficiency than those with PAA, because of the electrochemical reduction of the PAA binder. This is identified by attenuated total reflectance Fourier transform infrared spectrometry and observed gassing during the electrochemical reaction. Coulombic losses from the PAA and Si SEI, along with depletion of the Si capacity in the anode results in progressive underutilization of the cathode and full cell capacity loss.

The adsorption of Pb(sup2+) and Cu(sup2+) onto gum ghatti-grafted poly(acrylamide-co-acrylonitrile) biodegradable hydrogel: isotherms and kinetic models

CSIR Research Space (South Africa)

Mittal, H

2015-01-01

Full Text Available A biodegradable hydrogel polymer of gum ghatti (Gg) with a copolymer mixture of acrylamide (AAm) and acrylonitrile (AN) was synthesized using the free-radical graft copolymerization technique. The effect of graft copolymerization on the surface area...

Effect of Grafted Hydroquinone on the Acid-Base Properties of Poly(acrylic acid in the Presence of Copper (II

Directory of Open Access Journals (Sweden)

Nabila Bensacia

2015-01-01

Full Text Available Potentiometric titration of poly(acrylic acid and hydroquinone-functionalized poly(acrylic acid was conducted in the presence of copper (II. The effects of hydroquinone functionalizing and copper (II complexing on the potentiometric titration of poly(acrylic acid were studied in an ionic environment and in its absence. Henderson-Hasselbalch equation was applied to assess its validity for this titration. Coordination number and the stability constants of the copper- (II-complexed polymers were determined, and results showed the formation of mostly monodentate and bidentate copper- (II-polymer complexes.

Graphene oxide and hyperbranched polymer-toughened hydrogels with improved absorption properties and durability

DEFF Research Database (Denmark)

Yu, Yang; De Andrade, Leandro Carvalho Xavier; Fang, Liming

2015-01-01

Hyperbranched polymers or/and graphene oxide nanosheets were used to synthesize poly(acrylic acid)-based hybrid hydrogels with high water absorption ability, excellent mechanical properties, and environmental remediation abilities through a novel one-step, cost-effective, and environmentally...... friendly method. The combination of hyperbranched polymers and graphene oxide nanosheets had synergistic effects on the final hybrid hydrogel, especially on the mechanical behaviors of the hydrogels, with Young's modulus, tensile strength at break and elongation at break increasing by 69, 308, and 848...

Effects of acrylamide and acrylic acid on creatine kinase activity in the rat brain

International Nuclear Information System (INIS)

Kohriyama, Kazuaki; Matsuoka, Masato; Igisu, Hideki

1994-01-01

In vitro, both acrylamide and acrylic acid inhibited creatine kinase (CK) activity in rat brain homogenates, and acrylic acid was more potent than acrylamide. In vivo, however, when given i.p. 50 mg/kg per day for 8 days to rats, only acrylamide inhibited CK activity in the brain and caused apparent neurological signs. 14 C in the brain 24 h after the injection of 14 C-labelled chemicals was more than 7 times greater with acrylamide than with acrylic acid. The inhibition of CK activity by acrylamide varied in eight regions of the brain; from 54% in hypothalamus to 27% in cerebellar vermis. The regional difference of CK inhibition, however, did not agree well with either 14 C distribution or with the distribution in regions which appear clinically or pathologically vulnerable to acrylamide. (orig.)

Comparison of Swelling and Mechanical Analysis for the Determination of Crosslink Density of Acrylamide Based Hydrogels Prepared by Ionizing Radiation

International Nuclear Information System (INIS)

Sen, M.

2006-01-01

One of the basic parameters that describes the structure of a hydrogel network is the molecular weight between cross-links or cross-link density of highly swollen network. Several theories have been proposed to calculate the average molecular weight between cross-links. In the highly swollen state, the constrained junction theory indicates that a real network exhibits properties closer to those of the phantom network model and molecular weight between cross-links can be calculated easily by using swelling and polymer-solvent based parameters such as molar volume of the swelling agent, polymer-solvent interaction parameter, functionality, specific volume of the polymer and polymer volume fraction in the relaxed state. Molecular weight between cross-links (M c a ver.) and effective cross-linking density (V e ) of a hydrogel can also be determined from shear modulus data obtained from compression tests. Our previous studies indicated that simple compression analyses and equations derived from Phantom network theory can be used for the determination of effective cross-link density of hydrogels without needing some polymer-solvent based parameters as in the case of swelling based determinations. The M c a ver. and V e values calculated from mechanical tests were found to be very close to the values obtained from swelling experiments. Slight differences observed were attributed to the uncertainty on the value of the χ parameter used in the expression related to swelling data. In this study the uncertainty in the polymer based parameter χ on the M c a ver. was discussed. Poly(acrylamide/methacrylamide) P(AAm/MAAm) and Poly(acrylamide/hydroxyethylmeth acrylate) P(AAm/HEMA) hydrogels were prepared by gamma rays and used as model hydrogel systems. The uniaxial compression was applied to cylindrical samples using the Universal Testing Instrument in the swollen form at pH 7. Stress-strain curves of hydrogels were evaluated to calculate the shear modulus values. The M c a ver

Low-cost removal of organic pollutants with nickel nanoparticle loaded ordered macroporous hydrogel as high performance catalyst

Energy Technology Data Exchange (ETDEWEB)

Tang, Mingyi, E-mail: tmyi@tjcu.edu.cn [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Huang, Guanbo, E-mail: gbhuang2007@hotmail.com [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Zhang, Sai [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Liu, Yue [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Li, Xianxian [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Wang, Xingrui [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China); Pang, Xiaobo [Department of Applied Chemistry, School of Science, Tianjin University of Commerce, Tianjin 300134 (China); Qiu, Haixia, E-mail: qhx@tju.edu.cn [Department of Chemistry, School of Science, Tianjin University, Tianjin 300072 (China)

2014-06-01

A facile route for the in situ preparation of catalytically active Ni nanoparticles (NPs) in ordered macroporous hydrogel (OMH) has been developed. The hydrogel was fabricated based on polystyrene colloid template. The electronegativity of amide and carboxyl groups on the poly(acrylamide-co-acryl acid) chains of the hydrogel caused strong binding of Ni{sup 2+} ions which made them distribute uniformly inside the hydrogel. When immersed in NaBH{sub 4} aqueous solution, the Ni{sup 2+} ions on the hydrogel were reduced to Ni NPs. The resultant Ni NPs loaded OMH showed good catalytic activity for the reduction of a common organic pollutant, 4-nitrophenol, with NaBH{sub 4}. A kinetic study of the catalytic reaction was carried out. The rate constant per unit weight could reach 0.53 s{sup −1} g{sup −1}, which is much better than many common hydrogel loaded nickel catalysts. Moreover, the current catalyst can be easily separated and recovered with stable catalytic activity. - Highlights: • A new poly(acrylamide-co-acryl acid) hydrogel with ordered macropores. • A simple in situ fabrication of nickel nanoparticles under mild conditions. • High-performance heterogeneous catalyst for removal of nitrophenol from water. • Good recyclability of catalyst without any complicated regeneration process.

Low-cost removal of organic pollutants with nickel nanoparticle loaded ordered macroporous hydrogel as high performance catalyst

International Nuclear Information System (INIS)

Tang, Mingyi; Huang, Guanbo; Zhang, Sai; Liu, Yue; Li, Xianxian; Wang, Xingrui; Pang, Xiaobo; Qiu, Haixia

2014-01-01

A facile route for the in situ preparation of catalytically active Ni nanoparticles (NPs) in ordered macroporous hydrogel (OMH) has been developed. The hydrogel was fabricated based on polystyrene colloid template. The electronegativity of amide and carboxyl groups on the poly(acrylamide-co-acryl acid) chains of the hydrogel caused strong binding of Ni 2+ ions which made them distribute uniformly inside the hydrogel. When immersed in NaBH 4 aqueous solution, the Ni 2+ ions on the hydrogel were reduced to Ni NPs. The resultant Ni NPs loaded OMH showed good catalytic activity for the reduction of a common organic pollutant, 4-nitrophenol, with NaBH 4 . A kinetic study of the catalytic reaction was carried out. The rate constant per unit weight could reach 0.53 s −1  g −1 , which is much better than many common hydrogel loaded nickel catalysts. Moreover, the current catalyst can be easily separated and recovered with stable catalytic activity. - Highlights: • A new poly(acrylamide-co-acryl acid) hydrogel with ordered macropores. • A simple in situ fabrication of nickel nanoparticles under mild conditions. • High-performance heterogeneous catalyst for removal of nitrophenol from water. • Good recyclability of catalyst without any complicated regeneration process

Hydrogel Walkers with Electro-Driven Motility for Cargo Transport.

Science.gov (United States)

Yang, Chao; Wang, Wei; Yao, Chen; Xie, Rui; Ju, Xiao-Jie; Liu, Zhuang; Chu, Liang-Yin

2015-08-28

In this study, soft hydrogel walkers with electro-driven motility for cargo transport have been developed via a facile mould-assisted strategy. The hydrogel walkers consisting of polyanionic poly(2-acrylamido-2-methylpropanesulfonic acid-co-acrylamide) exhibit an arc looper-like shape with two "legs" for walking. The hydrogel walkers can reversibly bend and stretch via repeated "on/off" electro-triggers in electrolyte solution. Based on such bending/stretching behaviors, the hydrogel walkers can move their two "legs" to achieve one-directional walking motion on a rough surface via repeated "on/off" electro-triggering cycles. Moreover, the hydrogel walkers loaded with very heavy cargo also exhibit excellent walking motion for cargo transport. Such hydrogel systems create new opportunities for developing electro-controlled soft systems with simple design/fabrication strategies in the soft robotic field for remote manipulation and transportation.

Use of monoglyceride hydrogel for the production of low fat short dough pastry.

Science.gov (United States)

Manzocco, Lara; Anese, Monica; Calligaris, Sonia; Quarta, Barbara; Nicoli, Maria Cristina

2012-05-01

The influence of palm oil replacement with a monoglyceride-palm oil-water gel (hydrogel) on physical properties and acrylamide content of a low fat short dough pastry was studied. The effect of the incorporation of the hydrogel was monitored during storage by assessing moisture, firmness, proton density/mobility using magnetic resonance imaging (MRI) and acrylamide content. The use of hydrogel allowed the lipid content of pastries to be reduced with minor effects on their quality characteristics. However, the hydrogel-containing pastries showed a crunchier crust, higher acrylamide content and a higher tendency to staling. As assessed by MRI, these results were ascribable to the development of a peculiar system morphology promoted by hydrogel incorporation in the food matrix. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of a novel poly (AA-co-AAm)/AlZnFe₂O₄/potassium humate superabsorbent hydrogel nanocomposite on water retention of sandy loam soil and wheat seedling growth.

Science.gov (United States)

Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

2012-10-25

A novel poly(acrylic acid-co-acrylamide)AlZnFe₂O₄/potassium humate( )superabsorbent hydrogel nanocomposite (PHNC) was synthesized and its physical properties characterized using SEM, Energy Dispersive X-ray (EDX) and FTIR spectroscopic techniques. Air dried sandy loam soil was amended with 0.1 to 0.4 w/w% of PHNC to evaluate its soil moisture retention attributes. Effect of PHNC amendment on pH, electrical conductivity (EC), porosity, bulk density and hydraulic conductivity of sandy loam soil was also studied. The soil amendment with 0.1 to 0.4 w/w% of PHNC remarkably enhanced the moisture retention at field capacity as compared to the un-amended soils. Seed germination and seedling growth of wheat (Triticum aestivum L.) was considerably increased and a delay by 6-9 days in wilting of seedlings was observed in the soil amended with PHNC, resulting in improved wheat plant establishment and growth.

Hydrogel-based piezoresistive sensor for the detection of ethanol

Directory of Open Access Journals (Sweden)

J. Erfkamp

2018-04-01

Full Text Available This article describes a low-cost sensor for the detection of ethanol in alcoholic beverages, which combines alcohol-sensitive hydrogels based on acrylamide and bisacrylamide and piezoresistive sensors. For reproducible measurements, the reversible swelling and deswelling of the hydrogel were shown via microscopy. The response time of the sensor depends on the swelling kinetics of the hydrogel. The selectivity of the hydrogel was tested in different alcohols. In order to understand the influence of monomer and crosslinker content on the swelling degree and on the sensitivity of the hydrogels, gels with variable concentrations of acrylamide and bisacrylamide were synthesized and characterized in different aqueous solutions with alcohol contents. The first measurements of such hydrogel-based piezoresistive ethanol sensors demonstrated a high sensitivity and a short response time over several measuring cycles.

Radiation preparation of drug carriers based polyacrylic acid (PAAc) using poly(vinyl pyrrolidone) (PVP) as a template polymer

Science.gov (United States)

Abd El-Rehim, H. A.; Hegazy, E. A.; Khalil, F. H.; Hamed, N. A.

2007-01-01

The present study deals with the radiation synthesis of stimuli response hydrophilic polymers from polyacrylic acid (PAAc). To maintain the property of PAAc and control the water swellibility for its application as a drug delivery system, radiation polymerization of AAc in the presence of poly(vinyl pyrrolidone) (PVP) as a template polymer was carried out. Characterization of the prepared PAA/PVP inter-polymer complex was investigated by determining gel content, swelling property, hydrogel microstructure and the release rate of caffeine as a model drug. The release rate of caffeine from the PAA/PVP inter-polymer complexes showed pH-dependency, and seemed to be mainly controlled by the dissolution rate of the complex above a p Ka of PAAc. The prepared inter-polymer complex could be used for application as drug carriers.

Adsorption of methyl violet from aqueous solution using gum xanthan/Fe3O4 based nanocomposite hydrogel

CSIR Research Space (South Africa)

Mittal, H

2016-08-01

Full Text Available This research paper reports the utilization of gum xanthan-grafted-polyacrylic acid and Fe(sub3)O(sub4) magnetic nanoparticles based nanocomposite hydrogel (NCH) for the highly effective adsorption of methyl violet (MV) from aqueous solution...

Novel 3D porous semi-IPN hydrogel scaffolds of silk sericin and poly(N-hydroxyethyl acrylamide for dermal reconstruction

Directory of Open Access Journals (Sweden)

S. Ross

2017-09-01

Full Text Available In this work, a novel semi-interpenetrating polymer network (semi-IPN hydrogel scaffold based on silk sericin (SS and poly(N-hydroxyethyl acrylamide (PHEA was successfully fabricated via conventional free-radical polymerization. The porous structure of the scaffolds was introduced using a lyophilization technique and the effect of cross-linker (XL on morphology, gelation time and physical properties of hydrogel scaffold was first studied. The results show that using low cross-linker content (0.125, 0.25 and 0.5 wt% XL produced flexible scaffolds and appropriate gelation times for fabricating the scaffold. Therefore, the polymerization system with a constant percentage of XL at 0.5 wt% was chosen to study further the effect of SS on the physical properties and cell culture of the scaffolds. It was observed that the hydrogel scaffold of PHEA without SS (PHEA/SS-0 had no cell proliferation, whereas hydrogel scaffolds with SS enhanced cell viability when compared to the positive control. The sample of PHEA/SS at 1.25 wt% of SS and 0.5 wt% of cross-linker was the most suitable for HFF-1 cells to migrate and cell proliferation due to possessing a connective porous structure, along with silk sericin. The results proved that this novel porous semi-IPN hydrogel has the potential to be used as dermal reconstruction scaffold.

Dynamically formed hydrous zirconium (IV) oxide-polyelectrolyte membranes. III: Poly(acrylic acid) and substituted poly(acrylic acid) homo, co and terpolymer membranes

International Nuclear Information System (INIS)

Van Reenen, A.J.; Sanderson, R.D.

1989-01-01

A series of acrylic acid and substituted acrylic acid homo, co and terpolymers was synthesised. These polymers were used as polyelectrolytes in dynamically formed hydrous zirconium (iv) oxide-polyelectrolyte membranes. Substitution of the acrylic acid α-hydrogen was done to increase the number of carboxylic acid groups per monomer unit and to change the acid strength of acrylic acid carboxylic acid group. None of these changes improved the salt rejection of these membranes over that of commercially used poly(acrylic acid). Improvement in rejection was found when a hydrophobic comonomer, vinyl acetate, was used in conjunction with acrylic acid in a copolymer dynamic membrane. 16 refs., 6 figs., 1 tab

Effect of maleic acid content on the thermal stability, swelling behaviour and network structure of gelatin-based hydrogels prepared by gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Eid, M. [National Center For Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo 11731 (Egypt)], E-mail: mona_eid2000@yahoo.com; Abdel-Ghaffar, M.A. [National Research Center, Dokki, Cairo (Egypt); Dessouki, A.M. [National Center For Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo 11731 (Egypt)

2009-01-15

The highly swelling Poly (acrylamide/maleic acid/gelatin) P(AAm/MA/G) hydrogels were prepared by gamma-irradiation at low dose rate (0.94 kGy/h) and moderate dose rate (3.84 kGy/h). The hydrogels were confirmed by FTIR. The effect of copolymer composition, dose and dose rate on the swelling behaviour was discussed. Increasing of MA content and G in the initial mixture leads to an increase in the amount of MA and G in the gel system and decrease in the gelation %. The swelling behaviours of the hydrogel prepared at moderate dose rate increased with increasing MA mole content in the gel system but, there is no systematic dependence of swelling on MA content was observed for the hydrogels obtained at low dose rate. Pore structure of the hydrogels was monitored by using scanning electron microscopy. Thermogravimetric analysis (TGA) and the rate of the thermal decomposition of P(AAm/MA/G) hydrogels has been evaluated to give a better understanding of the thermal stability of polymers, The X-ray data of P(AAm/MA/G) hydrogels was discussed to investigate some features namely the degree of ordering and crystallite size.

Investigation of the degradation and stability of acrylamide-based polymers in acid solution: Functional monomer modified polyacrylamide

Directory of Open Access Journals (Sweden)

Yuxin Pei

2016-12-01

Full Text Available Acrylamide copolymers are often used as acidizing diverting and thickening agents for their advantageous thickening, flocculation, adhesion and resistance reduction properties. Experimental results indicate that the acid concentration greatly affects the properties of acrylamide polymers, which varies from results reported by other researchers. Considering the theoretical and field application value of the present study, four comparable acrylamide-based polymers were synthesized, and their macro- and micro-changes as well as the related changes in viscosity and molecular weight were studied in high-concentration hydrochloric acid. A proposed mechanism of acrylamide copolymer stability and degradation is provided, and further suggestions are made for the modification of acrylamide copolymers.

Swelling, Mechanics, and Thermal/Chemical Stability of Hydrogels Containing Phenylboronic Acid Side Chains

Directory of Open Access Journals (Sweden)

Arum Kim

2017-12-01

Full Text Available We report here studies of swelling, mechanics, and thermal stability of hydrogels consisting of 20 mol % methacrylamidophenylboronic acid (MPBA and 80 mol % acrylamide (AAm, lightly crosslinked with methylenebisacrylamide (Bis. Swelling was measured in solutions of fixed ionic strength, but with varying pH values and fructose concentrations. Mechanics was studied by compression and hold. In the absence of sugar or in the presence of fructose, the modulus was mostly maintained during the hold period, while a significant stress relaxation was seen in the presence of glucose, consistent with reversible, dynamic crosslinks provided by glucose, but not fructose. Thermal stability was determined by incubating hydrogels at pH 7.4 at room temperature, and 37, 50, and 65 °C, and monitoring swelling. In PBS (phosphate buffered saline solutions containing 9 mM fructose, swelling remained essentially complete for 50 days at room temperature, but decreased substantially with time at the higher temperatures, with accelerated reduction of swelling with increasing temperature. Controls indicated that over long time periods, both the MPBA and AAm units were experiencing conversion to different species.

Role of superporous hydrogel particles as a superdisintegrant in fast disintegrating tablet of Glipizide

Directory of Open Access Journals (Sweden)

Hitesh V Chavda

2014-01-01

Full Text Available Background: Superporous hydrogel (SPH swells very rapidly in a shorter period of time to an equilibrium size and contains highly porous structure. The literature survey reflects the preparation of SPHs and its composite, but its application as an excipient in a drug delivery system is not well focused. Aim: Efforts were made to develop fast disintegrating tablets of Glipizide using superporous hydrogel particles (SPHPs as a wicking agent, which act as a superdisintegrant to decrease disintegration time. Materials and Methods: The SPH of poly (acrylamide-co-acrylic acid was prepared by solution polymerization and characterized. Prepared tablets were evaluated for concerned parameters. Formulation optimization was carried out using 3 2 full factorial design and analysis of variance. Results: Scanning electron microscopy pictures clearly confirmed the superporous structure of hydrogel. Batch F 4 containing 4% w/w of SPH of poly (acrylamide-co-acrylic acid as a superdisintegrant showed extremely fast wicking effect and lesser disintegration time compared with other potential superdisintegrants. Drug release was good compared with conventional immediate release marketed product. Conclusion: It can be concluded that SPHPs can be used as a potential superdisintegrant in tablet formulation.

Optical sensing properties of Au nanoparticle/hydrogel composite microbeads using droplet microfluidics

Science.gov (United States)

Li, Huilin; Men, Dandan; Sun, Yiqiang; Zhang, Tao; Hang, Lifeng; Liu, Dilong; Li, Cuncheng; Cai, Weiping; Li, Yue

2017-10-01

Uniform Au nanoparticle (NP)/poly (acrylamide-co-acrylic acid) [P(AAm-co-AA)] hydrogel microbeads were successfully prepared using droplet microfluidics technology. The microbeads exhibited a good stimuli-responsive behavior to pH value. Particularly in the pH value ranging from pH 2-pH 9, the composite microbead sizes gradually increased along with the increase of pH value. The homogeneous Au NPs, which were encapsulated in the P(AAm-co-AA) hydrogel microbeads, could transform the volume changes of hydrogel into optical signals by a tested single microbead with a microspectrometre system. The glucose was translated into gluconic acid by glucose oxidase. Thus, the Au NP/P(AAm-co-AA) hydrogel microbeads were used for detecting glucose based on pH effects on the composite microbeads. For this, the single Au NP/P(AAm-co-AA) hydrogel microbead could act as a good pH- or glucose-visualizing sensor.

Reusable self-healing hydrogels realized via in situ polymerization.

Science.gov (United States)

Vivek, Balachandran; Prasad, Edamana

2015-04-09

In this work, a self-healing hydrogel has been prepared using in situ polymerization of acrylic acid and acrylamide in the presence of glycogen. The hydrogel was characterized using NMR, SEM, FT-IR, rheology, and dynamic light scattering (DLS) studies. The developed hydrogel exhibits self-healing properties at neutral pH, high swelling ability, high elasticity, and excellent mechanical strength. The hydrogel exhibits modulus values (G', G″) as high as 10(6) Pa and shows an exceptionally high degree of swelling ratio (∼3.5 × 10(3)). Further, the polymer based hydrogel adsorbs toxic metal ions (Cd(2+), Pb(2+), and Hg(2+)) and organic dyes (methylene blue and methyl orange) from contaminated water with remarkable efficiency (90-98%). The mechanistic analysis indicated the presence of pseudo-second-order reaction kinetics. The reusability of the hydrogel has been demonstrated by repeating the adsorption-desorption process over five cycles with identical results in the adsorption efficiency.

Preparation and characterization of gum karaya hydrogel nanocomposite flocculant for metal ions removal from mine effluents

CSIR Research Space (South Africa)

Fosso-Kankeu, E

2016-02-01

Full Text Available This research paper reports the removal of heavy metal ions from mine effluents using the gum karaya (GK)-grafted poly(acrylamide-co-acrylic acid) incorporated iron oxide magnetic nanoparticles (Fe3O4 MNPs) hydrogel nanocomposite [i.e., GK...

Cytotoxicity and metal ions removal using antibacterial biodegradable hydrogels based on N-quaternized chitosan/poly(acrylic acid).

Science.gov (United States)

Mohamed, Riham R; Elella, Mahmoud H Abu; Sabaa, Magdy W

2017-05-01

Physically crosslinked hydrogels resulted from interaction between N,N,N-trimethyl chitosan chloride (N-Quaternized Chitosan) (NQC) and poly(acrylic acid) (PAA) were synthesized in different weight ratios (3:1), (1:1) and (1:3) taking the following codes Q3P1, Q1P1 and Q1P3, respectively. Characterization of the mentioned hydrogels was done using several analysis tools including; FTIR, XRD, SEM, TGA, biodegradation in simulated body fluid (SBF) and cytotoxicity against HepG-2 liver cancer cells. FTIR results proved that the prepared hydrogels were formed via electrostatic and H-bonding interactions, while XRD patterns proved that the prepared hydrogels -irrespective to their ratios- were more crystalline than both matrices NQC and PAA. TGA results, on the other hand, revealed that Q1P3 hydrogel was the most thermally stable compared to the other two hydrogels (Q3P1 and Q1P1). Biodegradation tests in SBF proved that these hydrogels were more biodegradable than the native chitosan. Examination of the prepared hydrogels for their potency in heavy metal ions removal revealed that they adsorbed Fe (III) and Cd (II) ions more than chitosan, while they adsorbed Cr (III), Ni (II) and Cu (II) ions less than chitosan. Moreover, testing the prepared hydrogels as antibacterial agents towards several Gram positive and Gram negative bacteria revealed their higher antibacterial activity as compared with NQC when used alone. Evaluating the cytotoxic effect of these hydrogels on an in vitro human liver cancer cell model (HepG-2) showed their good cytotoxic activity towards HepG-2. Moreover, the inhibition rate increased with increasing the hydrogels concentration in the culture medium. Copyright © 2017 Elsevier B.V. All rights reserved.

Dual patterning of a poly(acrylic acid) layer by electron-beam and block copolymer lithographies.

Science.gov (United States)

Pearson, Anthony C; Linford, Matthew R; Harb, John N; Davis, Robert C

2013-06-18

We show the controllable patterning of palladium nanoparticles in both one and two dimensions using electron-beam lithography and reactive ion etching of a thin film of poly(acrylic acid) (PAA). After the initial patterning of the PAA, a monolayer of polystyrene-b-poly-2-vinylpyridine micelles is spun cast onto the surface. A short reactive ion etch is then used to transfer the micelle pattern into the patterned poly(acrylic acid). Finally, PdCl2 is loaded from solution into the patterned poly(acrylic acid) features, and a reactive-ion etching process is used to remove the remaining polymer and form Pd nanoparticles. This method yields location-controlled patches of nanoparticles, including single- and double-file lines and nanoparticle pairs. A locational accuracy of 9 nm or less in one direction was achieved by optimizing the size of the PAA features.

Synthesis, characterization and rheological behavior of pH sensitive poly(acrylamide-co-acrylic acid hydrogels

Directory of Open Access Journals (Sweden)

Seddiki Nesrinne

2017-05-01

Results indicated that the strong interaction in the hydrogels resulted in the formation of a more stable copolymer. The single glass transition temperature (Tg in sample suggested that the two polymers into the hydrogel have a good miscibility. The elastic modulus (G′ and linear viscoelastic region increased with increase in PAAc concentration. The oscillation time sweep study of the hydrogels exhibited a flat G′ indicating a stable structure and good mechanical strength. In the swelling measurements, the gels exhibited appreciable water uptake and were highly sensitive to pH environment. So the poly(AAm-co-AAc hydrogel will have promising application in pharmaceutical use and in biomaterials.

NOVEL SUPERABSORBENT HYDROGEL COMPOSITE BASED ON POLY(ACRYLAMIDE-CO-ACRYLATE/NONTRONITE: CHARACTERIZATION AND SWELLING PERFORMANCE

Directory of Open Access Journals (Sweden)

Renan C. F. Leitão

2015-03-01

Full Text Available A novel superabsorbent hydrogel (SH composite based on a poly(acrylamide-co-acrylate matrix filled with nontronite (NONT, a Fe(III-rich member of the smectite group of clay minerals, is described in this manuscript. A variety of techniques, including FTIR, XRD, TGA, and SEM/EDX, were utilized to characterize this original composite. Experimental data confirmed the SH composite formation and suggested NONT was completely dispersed in the polymeric matrix. Additionally, NONT improved the water uptake capacity of the final material, which exhibited fast absorption, low sensitivity to the presence of salt, high water retention and a pH sensitive properties. These preliminary data showed that the original SH composite prepared here possesses highly attractive properties for applications in areas such as the agriculture field, particularly as a soil conditioner.

Antiviral Activity of Polyacrylic and Polymethacrylic Acids

Science.gov (United States)

De Somer, P.; De Clercq, E.; Billiau, A.; Schonne, E.; Claesen, M.

1968-01-01

Polyacrylic acid (PAA) and polymethacrylic acid (PMAA) were investigated for their antiviral properties in tissue culture. Compared to other related polyanions, as dextran sulfate, polystyrene sulfonate, polyvinyl sulfate, and polyphloroglucinol phosphate, PAA and PMAA were found to be significantly more antivirally active and less cytotoxic. PMAA added 24 hr prior to virus inoculation inhibited viral growth most efficiently but it was still effective when added 3 hr after infection. Neither a direct irreversible action on the virus nor inhibition of virus penetration into the cell could explain the antiviral activity of PMAA. PMAA inhibited the adsorption of the virus to the host cell and suppressed the one-cycle viral synthesis in tissue cultures inoculated with infectious RNA. PMID:4302187

Extraction of metal cations by polyterephthalamide microcapsules containing a poly(acrylic acid) gel.

Science.gov (United States)

Laguecir, A; Ernst, B; Frère, Y; Danicher, L; Burgard, M

2002-01-01

Polyterephthalamide microcapsules containing a poly(acrylic acid) gel as a macromolecular ligand (PAA-CAPS) were prepared using an original two step polymerization process in a water-in-oil inverse emulsion system. A polyamide microcapsule containing acrylic acid, initiator and cross-linking agent, is formed by interfacial polycondensation of terephthaloyl dichloride with hexamethylenediamine. In situ radical polymerization of the microcapsule core acrylic acid is initiated to obtain encapsulated poly(acrylic acid) gel. Reference polyamide microcapsules, i.e. without ligand (CAPS), were also synthesized. The mean diameter of synthesized microcapsules was 210 microm, and the microcapsule wall thickness was evaluated by SEM and TEM observations of microcapsule cross-section cuts. The microcapsule water content was determined by thermogravimetric experiments. The extractabilities of Cu(II), Ni(II), Co(II) and Zn(II) into PAA-CAPS were examined. The stripping of the various cations can be promoted in diluted hydrochloric acid solutions.

Effects of Fungicide Treatment on Free Amino Acid Concentration and Acrylamide-Forming Potential in Wheat.

Science.gov (United States)

Curtis, Tanya Y; Powers, Stephen J; Halford, Nigel G

2016-12-28

Acrylamide forms from free asparagine and reducing sugars during frying, baking, roasting, or high-temperature processing, and cereal products are major contributors to dietary acrylamide intake. Free asparagine concentration is the determining factor for acrylamide-forming potential in cereals, and this study investigated the effect of fungicide application on free asparagine accumulation in wheat grain. Free amino acid concentrations were measured in flour from 47 varieties of wheat grown in a field trial in 2011-2012. The wheat had been supplied with nitrogen and sulfur and treated with growth regulators and fungicides. Acrylamide formation was measured after the flour had been heated at 180 °C for 20 min. Flour was also analyzed from 24 (of the 47) varieties grown in adjacent plots that were treated in identical fashion except that no fungicide was applied, resulting in visible infection by Septoria tritici, yellow rust, and brown rust. Free asparagine concentration in the fungicide-treated wheat ranged from 1.596 to 3.987 mmol kg -1 , with a significant (p fungicide treatment, the increases in acrylamide ranging from 2.7 to 370%. Free aspartic acid concentration also increased, whereas free glutamic acid concentration increased in some varieties but decreased in others, and free proline concentration decreased. The study showed disease control by fungicide application to be an important crop management measure for mitigating the problem of acrylamide formation in wheat products.

THE USE OF POLYSACCHARIDES EXTRACTED FROM SEED OF Persea americana var. Hass ON THE SYNTHESIS OF ACRYLIC HYDROGELS

Directory of Open Access Journals (Sweden)

Vicente Arturo Lara-Valencia

Full Text Available This paper reports the use of polysaccharides extracted from seed of Persea americana var. Hass in the synthesis of acrylic hydrogels. The effects of the chemical composition (acrylamide/acrylic acid, the concentration of crosslinking agent (glycerol diacrylate and the type of initiation (redox, photoinitiation of the hydrogels were evaluated with and without polysaccharides. Xerogels were characterized by FTIR spectroscopy, differential scanning calorimetry (DSC and scanning electron microscopy (SEM, while for the swollen hydrogels the swelling kinetic and mechanical properties were evaluated. The kinetic parameters were obtained using the second order equation proposed by Schott, where it is reported that by increasing the concentration of the crosslinking agent, the degree of swelling is reduced because of the greater structural level. The increase of the amount of acrylamide and the amount of polysaccharides causes also a decrease in the swelling degree. The type of initiation also affected the hydrogels swelling kinetic, the photoinitiated hydrogels were the ones that captured less water. Moreover, the increasing of the glass transition temperature and the compression modulus with the crosslinking agent concentration and molar ratio AAm/AAc are observed for hydrogels with and without polysaccharides. The results demonstrate a successful incorporation of polysaccharides into the polymeric network.

Acrylamide neurotoxicity on the cerebrum of weaning rats

Directory of Open Access Journals (Sweden)

Su-min Tian

2015-01-01

Full Text Available The mechanism underlying acrylamide-induced neurotoxicity remains controversial. Previous studies have focused on acrylamide-induced toxicity in adult rodents, but neurotoxicity in weaning rats has not been investigated. To explore the neurotoxic effect of acrylamide on the developing brain, weaning rats were gavaged with 0, 5, 15, and 30 mg/kg acrylamide for 4 consecutive weeks. No obvious neurotoxicity was observed in weaning rats in the low-dose acrylamide group (5 mg/kg. However, rats from the moderate- and high-dose acrylamide groups (15 and 30 mg/kg had an abnormal gait. Furthermore, biochemical tests in these rats demonstrated that glutamate concentration was significantly reduced, and γ-aminobutyric acid content was significantly increased and was dependent on acrylamide dose. Immunohistochemical staining showed that in the cerebral cortex, γ-aminobutyric acid, glutamic acid decarboxylase and glial fibrillary acidic protein expression increased remarkably in the moderate- and high-dose acrylamide groups. These results indicate that in weaning rats, acrylamide is positively associated with neurotoxicity in a dose-dependent manner, which may correlate with upregulation of γ-aminobutyric acid and subsequent neuronal degeneration after the initial acrylamide exposure.

Structure of polyacrylic acid and polymethacrylic acid solutions : a small angle neutron scattering study

OpenAIRE

Moussaid , A.; Schosseler , F.; Munch , J.; Candau , S.

1993-01-01

The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiemnts. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to t...

Rationalisation and Validation of an Acrylamide-Free Procedure in Three-Dimensional Histological Imaging

Science.gov (United States)

Lai, Hei Ming; Liu, Alan King Lun; Ng, Wai-Lung; DeFelice, John; Lee, Wing Sang; Li, Heng; Li, Wen; Ng, Ho Man; Chang, Raymond Chuen-Chung; Lin, Bin; Wu, Wutian; Gentleman, Steve M.

2016-01-01

Three-dimensional visualization of intact tissues is now being achieved by turning tissues transparent. CLARITY is a unique tissue clearing technique, which features the use of detergents to remove lipids from fixed tissues to achieve optical transparency. To preserve tissue integrity, an acrylamide-based hydrogel has been proposed to embed the tissue. In this study, we examined the rationale behind the use of acrylamide in CLARITY, and presented evidence to suggest that the omission of acrylamide-hydrogel embedding in CLARITY does not alter the preservation of tissue morphology and molecular information in fixed tissues. We therefore propose a novel and simplified workflow for formaldehyde-fixed tissue clearing, which will facilitate the laboratory implementation of this technique. Furthermore, we have investigated the basic tissue clearing process in detail and have highlighted some areas for targeted improvement of technologies essential for the emerging subject of three-dimensional histology. PMID:27359336

Structure and properties of semi-interpenetrating network hydrogel based on starch.

Science.gov (United States)

Zhu, Baodong; Ma, Dongzhuo; Wang, Jian; Zhang, Shuang

2015-11-20

Starch-g-P(acrylic acid-co-acrylamide)/PVA semi-interpenetrating network (semi-IPN) hydrogels were prepared by aqueous solution polymerization method. Starch grafting copolymerization reaction, semi-IPN structure and crystal morphology were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The PVA in the form of partial crystallization distributing in the gel matrix uniformly were observed by Field emission scanning electron microscope (FESEM). The space network structure, finer microstructure and pore size in the interior of hydrogel were presented by biomicroscope. The results demonstrated that absorption ratio of water and salt generated different degree changes with the effect of PVA. In addition, the mechanical strength of hydrogel was improved. Copyright © 2015 Elsevier Ltd. All rights reserved.

Controlling acrylamide in French fry and potato chip models and a mathematical model of acrylamide formation: acrylamide: acidulants, phytate and calcium.

Science.gov (United States)

Park, Yeonhwa; Yang, Heewon; Storkson, Jayne M; Albright, Karen J; Liu, Wei; Lindsay, Robert C; Pariza, Michael W

2005-01-01

We previously reported that in potato chip and French fry models, the formation of acrylamide can be reduced by controlling pH during processing steps, either by organic (acidulants) or inorganic acids. Use of phytate, a naturally occurring chelator, with or without Ca++ (or divalent ions), can reduce acrylamide formation in both models. However, since phytate itself is acidic, the question remains as to whether the effect of phytate is due to pH alone or to additional effects. In the French fry model, the effects on acrylamide formation of pH, phytate, and/or Ca++ in various combinations were tested in either blanching or soaking (after blanching) steps. All treatments significantly reduced acrylamide levels compared to control. Among variables tested, pH may be the single most important factor for reducing acrylamide levels, while there were independent effects of phytate and/or Ca++ in this French fry model. We also developed a mathematical formula to estimate the final concentration of acrylamide in a potato chip model, using variables that can affect acrylamide formation: glucose and asparagine concentrations, cut potato surface area and shape, cooking temperature and time, and other processing conditions.

Conversion of Lignocellulosic Bagasse Biomass into Hydrogel

Directory of Open Access Journals (Sweden)

Farzaneh Amiri

2016-11-01

Full Text Available In recent years, the main objective of developing new hydrogel systems has been to convert biomass into environmentally-friendly hydrogels. Hybrid hydrogels are usually prepared by graft copolymerization of acrylic monomers onto natural polymers or biomass. In this study, sugarcane bagasse was used to prepare semi-synthetic hybrid hydrogels without delignification, which is a costly and timeconsuming process. Sugarcane bagasse as a source of polysaccharide was modified using polymer microgels based on acrylic monomers such as acrylic acid, acrylamide and 2-acrylamido-2-methyl propane sulfonic acid which were prepared through inverse emulsion polymerization. By this process, biomass as a low-value by-product was converted into a valuable semi-synthetic hydrogel. In the following, the effect of latex type¸ the aqueous-to-organic phase ratio in the polymer latex, time and temperature of modification reaction on the swelling capacity of the hybrid hydrogel were evaluated. The chemical reaction between sugarcane bagasse and acrylic latex was carried out during heating of the modified bagasse which led to obtain a semisynthetic hydrogel with 60% natural components and 40% synthetic components. Among the latexes with different structures, poly(AA-NaAA-AM-AMPS was the most suitable polymer latex for the conversion of biomass into hydrogel. The bagasse modified with this latex had a water absorption capacity up to 112 g/g, while the water absorption capacity of primary sugarcane bagasse was only equal to 3.6 g/g. The prepared polymer hydrogels were characterized using Fourier transform infrared spectroscopy (FTIR, dynamic-mechanical thermal analysis (DMTA, thermal gravimetric analysis (TGA, scanning electron microscopy (SEM and determination of the amount of swelling capacity.

Evidence for the complex relationship between free amino acid and sugar concentrations and acrylamide-forming potential in potato

Science.gov (United States)

Muttucumaru, N; Powers, SJ; Elmore, JS; Briddon, A; Mottram, DS; Halford, NG

2014-01-01

Free amino acids and reducing sugars participate in the Maillard reaction during high-temperature cooking and processing. This results not only in the formation of colour, aroma and flavour compounds, but also undesirable contaminants, including acrylamide, which forms when the amino acid that participates in the reaction is asparagine. In this study, tubers of 13 varieties of potato (Solanum tuberosum), which had been produced in a field trial in 2010 and sampled immediately after harvest or after storage for 6 months, were analysed to show the relationship between the concentrations of free asparagine, other free amino acids, sugars and acrylamide-forming potential. The varieties comprised five that are normally used for crisping, seven that are used for French fry production and one that is used for boiling. Acrylamide formation was measured in heated flour, and correlated with glucose and fructose concentration. In French fry varieties, which contain higher concentrations of sugars, acrylamide formation also correlated with free asparagine concentration, demonstrating the complex relationship between precursor concentration and acrylamide-forming potential in potato. Storage of the potatoes for 6 months at 9°C had a significant, variety-dependent impact on sugar and amino acid concentrations and acrylamide-forming potential. PMID:25540460

Itaconic acid based potential sorbent for uranium recovery

International Nuclear Information System (INIS)

Kalyan, Y.; Naidu, G.R.K.; Das, Sadananda; Pandey, A.K.; Reddy, A.V.R.

2010-01-01

Cross-linked hydrogels and adsorptive membranes containing Itaconic acid, Acrylamide, Penta erythritol tetra acrylate and α, α-dimethyl- α-phenyl aceto phenone were prepared by UV-initiated bulk polymerization. These hydrogels and adsorptive membranes were characterized for pH uptake, sorption and desorption kinetics and selectivity towards uranium. The sorption ability of the sorbents towards uranyl ion was thoroughly examined. The developed itaconic acid based sorbents were evaluated for the recovery of uranium from lean sources like sea water. (author)

Synthesis and characterization of amylose grafted poly(acrylic acid) and its application in ammonia adsorption.

Science.gov (United States)

Chen, Qing; Yu, Haojie; Wang, Li; Abdin, Zain-Ul; Yang, Xinpeng; Wang, Junhua; Zhou, Weidong; Zhang, Hongtao; Chen, Xiao

2016-11-20

Amylose grafted poly(acrylic acid) (Am-g-PAA) was synthesized by graft copolymerization of amylose with acrylic acid. The structure of Am-g-PAA was confirmed by (1)H NMR and FT-IR spectra. The morphology, crystallinity and thermal properties of amylose and Am-g-PAA were investigated by SEM, XRD and TGA, respectively. The highest degree of substitution (DS) of carboxyl group was 1.96 which was obtained after reacted for 1h at 60°C. Acrylic acid to anhydroglucose mole ratio for DS was 19.81. It was found that a large number of carboxyl groups were grafted on the backbone of amylose. It was also found that ammonia adsorption capacity of amylose increased by grafting poly(acrylic acid) on the backbone of amylose. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of acid additives on graft copolymerization and water absorption of graft copolymers of cassava starch and acrylamide/acrylic acid

International Nuclear Information System (INIS)

Kiatkamjornwong, Suda; Mongkolsawat, Kanlaya; Sonsuk, Manit

2003-01-01

Gelatinized cassava starch was radiation graft copolymerized with acrylamide or acrylic acid in the presence of sulfuric acid, nitric acid or maleic acid at a specific dose rate to a fixed total dose. Homopolymer or free copolymer was extracted by water to obtain the pure graft copolymer, which was subsequently saponified with 5% potassium hydroxide solution at room temperature for 90 min. The saponified graft copolymer was investigated for the effect of acid additives and water absorption. The addition of 2% maleic acid into the grafting reaction containing acrylamide-to-starch ratio of 2.5:1 can produce the superabsorbent copolymer having water absorption as high as 2,256 ± 25 g g -1 . The effect of acid additive was explained. (author)

Radiation Synthesis of Stimuli-Responsive Hydrogels for Biological Applications

International Nuclear Information System (INIS)

Eid, M.; Hegazy, S.A.

2009-01-01

Poly(acrylamide/maleic acid/gelatin) P(AAm/MA/G) hydrogel networks were synthesized by 60 Co gamma irradiation at different doses. The properties of the hydrogels such as gelation percent, porosity, and moisture retention were investigated. The swelling ratio (S), equilibrium water content (EWC) and diffusion characteristics, including equilibrium swelling ratio (ESR), diffusion constant (n) and diffusion coefficients (D) were investigated and a non-Fickian type of diffusion characteristics was found in all the swelling media for the diffusion of water into these hydrogels. Further, the swelling pattern of P(AAm/MA/G) hydrogels was studied in different physiological bio-fluids, ph and ionic/salt solutions and showed great responsiveness due to their ionic character. The penetration velocity (v) of these biological fluids into such hydrogels was also calculated and it was found to be the maximum in urea and the minimum in synthetic urine. The higher equilibrium water content of these hydrogels, promotes them to be used as biomedical/pharmaceutical technology. The caffeine release as a drug model has been studied at ph 1 and ph 7 to resemble the ph of the stomach and the intestine, respectively. The caffeine release was controlled by the hydrogel crosslinking density that caused in increase of the irradiation dose

Interpolymer complexses of vinyl ether copolymer with polyacrylic and polymethacrylic acids

Directory of Open Access Journals (Sweden)

E. Shaikhutdinov

2012-03-01

Full Text Available The interactions between macromolecules of copolymers based on vinyl ethers (vinyl ether of monoethanolamine and vinyl buthyl ether and 2-acryloilamido-2-methylpropanesulphonic acid with polyacrylic and polymethacrylic acid and, as well as study the effect of interpolymer interactions in the adsorption of polymers at the aqueous solution-air interface were investigated. The observed synergistic increase in surface activity of macromolecules into polyelectrolyte mixtures explained by the formation of interpolymer complexes polyacid - copolymer.

Fabrication and Properties of polyacrylic acid by ionic surfactant disturbance method

Science.gov (United States)

Lawan, S.; Osotchan, T.; Chuajiw, W.; Subannajui, K.

2017-09-01

The formation of polymeric materials can be achieved by several methods such as melting and casting, screw extrusion, cross-linking of resin or rubber in a mold, and so on. In this work, the polyacrylic acid is formed by using the emulsion disturbance method. Despite extensively used in the colour painting and coating industries, acrylic emulsion can be processed into a foam and powder configuration by a reaction between acrylic emulsion and salt. The solidification hardly changes the volume between liquid emulsion and solidified polymer which means the final structure of polyacrylic acid is filled with opened air cells. The opened air cell structure is confirmed by the result from scanning electron microscopy. The chemical analysis and crystallography of acrylic powder and foam are examined by Fourier-transform infrared spectroscopy and X-ray diffraction respectively. The phase transformation and Thermal stability are studied by differential scanning calorimetry and thermo gravimetric analysis. Moreover, the mechanical properties of acrylic foam were observed by tensile, compressive and hardness test. In addition to the basic property analysis, acrylic foam was also used in the particle filtration application.

Bioinspired bioadhesive polymers: dopa-modified poly(acrylic acid) derivatives.

Science.gov (United States)

Laulicht, Bryan; Mancini, Alexis; Geman, Nathanael; Cho, Daniel; Estrellas, Kenneth; Furtado, Stacia; Hopson, Russell; Tripathi, Anubhav; Mathiowitz, Edith

2012-11-01

The one-step synthesis and characterization of novel bioinspired bioadhesive polymers that contain Dopa, implicated in the extremely adhesive byssal fibers of certain gastropods, is reported. The novel polymers consist of combinations of either of two polyanhydride backbones and one of three amino acids, phenylalanine, tyrosine, or Dopa, grafted as side chains. Dopa-grafted hydrophobic backbone polymers exhibit as much as 2.5 × the fracture strength and 2.8 × the tensile work of bioadhesion of a commercially available poly(acrylic acid) derivative as tested on live, excised, rat intestinal tissue. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of visible-light responsive and mechanically enhanced "smart" UCST interpenetrating network hydrogels.

Science.gov (United States)

Xu, Yifei; Ghag, Onkar; Reimann, Morgan; Sitterle, Philip; Chatterjee, Prithwish; Nofen, Elizabeth; Yu, Hongyu; Jiang, Hanqing; Dai, Lenore L

2017-12-20

An interpenetrating polymer network (IPN), chlorophyllin-incorporated environmentally responsive hydrogel was synthesized and exhibited the following features: enhanced mechanical properties, upper critical solution temperature (UCST) swelling behavior, and promising visible-light responsiveness. Poor mechanical properties are known challenges for hydrogel-based materials. By forming an interpenetrating network between polyacrylamide (PAAm) and poly(acrylic acid) (PAAc) polymer networks, the mechanical properties of the synthesized IPN hydrogels were significantly improved compared to hydrogels made of a single network of each polymer. The formation of the interpenetrating network was confirmed by Fourier Transform Infrared Spectroscopy (FTIR), the analysis of glass transition temperature, and a unique UCST responsive swelling behavior, which is in contrast to the more prevalent lower critical solution temperature (LCST) behaviour of environmentally responsive hydrogels. The visible-light responsiveness of the synthesized hydrogel also demonstrated a positive swelling behavior, and the effect of incorporating chlorophyllin as the chromophore unit was observed to reduce the average pore size and further enhance the mechanical properties of the hydrogel. This interpenetrating network system shows potential to serve as a new route in developing "smart" hydrogels using visible-light as a simple, inexpensive, and remotely controllable stimulus.

Physical-Mechanical Properties and Micromorphology of Calcium Cements Exposed to Polyacrylic and Phosphoric Acids.

Science.gov (United States)

de Souza, Gustavo Fernandes; Arrais, Ana Beatriz; Aragão, Cícero Flávio Soares; Ferreira, Isana Alvares; Borges, Boniek Castillo Dutra

2018-01-01

To evaluate if physical and mechanical properties of self-curing calcium hydroxide cements were affected by contact with polyacrylic and phosphoric acids. Resin-containing (Life (LF)) and resin-free (Hydro C (HyC)) materials were subjected to polyacrylic acid conditioning and rinsing (POL); phosphoric acid conditioning and rinsing (PHO); rinsing only; and no treatment ( n = 10). Water sorption/solubility, release of hydroxyl ions (pH), roughness (Ra), and impact resistance were evaluated. Additional samples ( n = 1) were prepared for scanning electron microscopy (SEM) analysis of the surface morphology. Data were analyzed by two-way ANOVA and Tukey post hoc test ( P < 0.05). Water sorption was significantly higher for LF when in contact with PHO and lower for POL ( P < 0.05). The mean solubility was higher with POL for both cements ( P < 0.05). PHO increased the mean surface roughness for HyC ( P < 0.01); a significant decrease was noted for LF after contact with both acids ( P < 0.01). PHO promoted lower release of hydroxyl ions on both cements ( P < 0.05). For LF, rinsing, PHO, and POL presented similar morphology, differing from the control group. For HyC, PHO and POL presented similar morphology, differing from the control group. PHO had a negative effect on the physical properties of the cements tested, except for the solubility test. POL affected roughness and solubility of HyC cement. Clinical procedures that require polyacrylic and phosphoric acid conditioning must be done carefully on self-curing calcium hydroxide cements in order to avoid negative impact on their properties.

Preparation of poly (2-hydroxyethyl methacrylate -co-acrylamide) hydrogels by gamma radiation: sol-gel analysis, swelling kinetic and mechanical behaviour

International Nuclear Information System (INIS)

Rapado Paneque, Manuel; Concepcion Villanueva, Daniel; Peniche, Carlos; Rosiak, Janusz M.

2006-01-01

2 hydroxyethyl methacrylate (HEMA) / acrylamide (Am) hydrogels were prepared by simultaneous radiation induced cross linking copolymerization. The G values of cross linking and degradation, gelation dose and further radiation parameters were estimated by sol/gel analysis. The dynamic swelling behaviour at 37 grade centigrade of these kind of materials was studied. The influence of the absorbed dose on the swelling degree at different pH was studied. It was observed that the kinetics is in good agreement with the second order diffusion kinetics proposed by Schott. The degree of cross linking was found to increase with the adsorbed dose and influence the mechanical properties to some extend. The molar mass of chain between the network cross links was estimated

Concentrations of free amino acids and sugars in nine potato varieties: effects of storage and relationship with acrylamide formation.

Science.gov (United States)

Halford, Nigel G; Muttucumaru, Nira; Powers, Stephen J; Gillatt, Peter N; Hartley, Lee; Elmore, J Stephen; Mottram, Donald S

2012-12-05

Acrylamide forms during cooking and processing predominately from the reaction of free asparagine and reducing sugars in the Maillard reaction. The identification of low free asparagine and reducing sugar varieties of crops is therefore an important target. In this study, nine varieties of potato (French fry varieties Maris Piper (from two suppliers), Pentland Dell, King Edward, Daisy, and Markies; and chipping varieties Lady Claire, Lady Rosetta, Saturna, and Hermes) grown in the United Kingdom in 2009 were analyzed at monthly intervals through storage from November 2009 to July 2010. Acrylamide formation was measured in heated flour and chips fried in oil. Analysis of variance revealed significant interactions between varieties nested within type (French fry and chipping) and storage time for most free amino acids, glucose, fructose, and acrylamide formation. Acrylamide formed in chips correlated significantly with acrylamide formed in flour and with chip color. There were significant correlations between glucose or total reducing sugar concentration and acrylamide formation in both variety types, but with fructose the correlation was much stronger for chipping than for French fry varieties. Conversely, there were significant correlations with acrylamide formation for both total free amino acid and free asparagine concentration in the French fry but not chipping varieties. The study showed the potential of variety selection for preventing unacceptable levels of acrylamide formation in potato products and the variety-dependent effect of long-term storage on acrylamide risk. It also highlighted the complex relationship between precursor concentration and acrylamide risk in potatoes.

Super absorbent hydrogel composites as water retentive in soil

International Nuclear Information System (INIS)

Magalhaes, Antonio Savio G.; Almeida Neto, Manuel P.; Bezerra, Maslandia N.; Feitosa, Judith P.A.

2011-01-01

Super absorbent hydrogels (SAP) were synthesized at room temperature, by the use of potassium persulfate as initiator, N,N'-methylene bis acrylamide (MBA) as crosslinking agent, and N,N,N',N'- tetramethylethylenediamine. Gels at the same conditions were prepared with 10% of minerals (bentonite or dolomite). The materials of bentonite series were obtained from acrylamide followed by hydrolysis with NaOH. The gels of dolomite series were prepared from the two co-monomers (acrylamide and acrylate). All SAPs were characterized by elemental microanalysis, FTIR, x-ray diffraction, SEM, and by swelling measurements in water. An intercalated composite was obtained with bentonite hydrogel. After hydrolysis an exfoliated nanocomposite was formed. The dolomite mineral was dispersed in the polymeric matrix. The swelling degrees of the SAPs with mineral were higher than those gels without it. This degree was 1,000 times the dry gel weight. Taking into account the amount of water needed to the process, the gel with dolomite is the most promising as soil conditioner. (author)

Thermo-sensitive and swelling properties of cellouronic acid sodium/poly (acrylamide-co-diallyldimethylammonium chloride) semi-IPN.

Science.gov (United States)

Zhang, Heng; Gao, Xin; Chen, Keli; Li, Hui; Peng, Lincai

2018-02-01

In current study, cellouronic acid sodium (CAS), obtained from bagasse pith, has been introduced into poly(acrylamide-co-diallyldimethylammonium chloride) (poly(AM-co-DAC)) network to form novel thermo-sensitive semi-IPNs. The structure and morphology of the hydrogels were proved by Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The effects of CAS content, initiator charge, cross-linker dosage and swelling-medium property on the thermo-responsive water absorptivity were investigated in detail. The results elucidated that the prepared gels exhibited a thermo-sensibility with an upper critical solution temperature (UCST) and a high water-absorbency. And the values of UCST and equilibrium swelling ratio largely depended on the inner structure of the semi-IPNs and the external solvent property. It was also revealed that the swelling process conformed to the Schott's pseudo second order model and diffusion type was non-Fickian diffusion. The value of activation energy for this polyelectrolyte was found to be 8.74kJ/mol. Copyright © 2017 Elsevier Ltd. All rights reserved.

The influence of fermented deffated flaxseed with difference lactic acid bacteria's on asparagine and acrylamide content in biscuits.

OpenAIRE

Bukauskienė, Gintarė

2016-01-01

It was evaluated the influence of solid state (SSF) and traditional (TF) fermentation with different lactobacillus (LAB) defatted flaxseeds on asparagine and acrylamide content in biscuits, and analysed correlation between fermented supplements physico chemical indicators and biscuits color and their sensory properties on acrylamide and asparagine content in biscuits. Correliations betweem acrylamide and asparagine content in biscuits and fermented supplements acidity parameters (pH, total t...

Biodegradation and Osteosarcoma Cell Cultivation on Poly(aspartic acid) Based Hydrogels.

Science.gov (United States)

Juriga, Dávid; Nagy, Krisztina; Jedlovszky-Hajdú, Angéla; Perczel-Kovách, Katalin; Chen, Yong Mei; Varga, Gábor; Zrínyi, Miklós

2016-09-14

Development of novel biodegradable and biocompatible scaffold materials with optimal characteristics is important for both preclinical and clinical applications. The aim of the present study was to analyze the biodegradability of poly(aspartic acid)-based hydrogels, and to test their usability as scaffolds for MG-63 osteoblast-like cells. Poly(aspartic acid) was fabricated from poly(succinimide) and hydrogels were prepared using natural amines as cross-linkers (diaminobutane and cystamine). Disulfide bridges were cleaved to thiol groups and the polymer backbone was further modified with RGD sequence. Biodegradability of the hydrogels was evaluated by experiments on the base of enzymes and cell culture medium. Poly(aspartic acid) hydrogels possessing only disulfide bridges as cross-links proved to be degradable by collagenase I. The MG-63 cells showed healthy, fibroblast-like morphology on the double cross-linked and RGD modified hydrogels. Thiolated poly(aspartic acid) based hydrogels provide ideal conditions for adhesion, survival, proliferation, and migration of osteoblast-like cells. The highest viability was found on the thiolated PASP gels while the RGD motif had influence on compacted cluster formation of the cells. These biodegradable and biocompatible poly(aspartic acid)-based hydrogels are promising scaffolds for cell cultivation.

A hydrogel-mediated scalable strategy toward core-shell polyaniline/poly(acrylic acid)-modified carbon nanotube hybrids as efficient electrodes for supercapacitor applications

Science.gov (United States)

Liu, Qingqing; Bai, Zhengyu; Fan, Jingbiao; Sun, Zhipeng; Mi, Hongyu; Zhang, Qing; Qiu, Jieshan

2018-04-01

Structural failure of polyaniline (PANI) stemmed from repeated swelling-shrinkage during Faradic process represents an imminent issue hindering the real application of this material for advanced energy storage. Herein, we explore a clean and facile hydrogel-mediated layer-by-layer strategy to conformally coat a layer of oriented PANI nanofibers on multi-walled carbon nanotubes (MWCNTs) where a layer of UV-polymerized poly(acrylic acid) (PAA) hydrogel is first formed in between as electrodes for supercapacitors. Such an intriguing core-shell tri-component structure perfectly alleviates the drawbacks of PANI as well as combines the advantages of MWCNTs. Especially, the hydrogel used increases the adhesion between PANI and MWCNTs, buffers the structural variation of PANI during cycling, and provide extra driving force accelerating electrolyte penetration throughout active materials. Therefore, the well-intergrown hybrids (PANI/P-MWCNT) display high electrochemical performance as compared to PANI and PANI/MWCNT, i.e., an improved capacitance of 612.5 F g-1 at 0.5 A g-1, and excellent cycling behavior of 81.5% capacitance retention at 5 A g-1 over 1500 cycles. Also, the maximum energy density of the PANI/P-MWCNT based symmetric configuration reaches 8.2 Wh kg-1. Significantly, such a hydrogel-bridged design concept may find the important application for the synthesis of competitive candidates for energy storage.

Controlled 5-fluorouracil release from hydrogels of Poly (acrylamide-co-metacrylic acid) crosslinked by means Of gamma irradiation techniques

International Nuclear Information System (INIS)

Rapado, M.; Sainz, D.; Altanes, S.; Prado, S.; Padron, S.; Salivar, D.; Chong, B.

1999-01-01

This report present the results on entrapped a cytostatic 5-Fluorouracil (5-F) in polymeric matrixes named hydrogels of polyacrylamide co -metacrylic acid crosslinked by means of gamma radiation with doses of 10,30, and 30 kGy at 25 o C. The drug delivery was followed by HPLC. The behavior of 5 -Fu migration from polymeric network was analyze by Iguchi equation for plain structure systems. The diffusion coefficients were obtained and drug release was in accordance with Fickian behavior

Gamma radiation synthesis of super absorbent hydrogels for different applications

International Nuclear Information System (INIS)

Marzouk, H.M.G.

2015-01-01

Super absorbent polymers (SAP) of carboxymethyl cellulose/acrylamide (CMC/PAM), carboxymethyl cellulose/acrylamide/Silica (CMC/AM/Si) and carboxymethyl cellulose/Polyvinyl alcohol (CMC/PVA) were synthesized by radiation-induced grafting using γ-irradiation technique. The effects of various parameters, such as irradiation dose, the content of CMC, PAM, PVA, and Silica gel on the swelling percent of produced hydrogels have been evaluated. The kinetic equilibrium swelling of the prepared copolymer hydrogels was studied, it was found that the maximum swelling percent was 5000 % for the CMC/PAM hydrogel, 12000 % for the CMC/PAM/Si composite hydrogel, and 6200 % for the CMC/PVA hydrogel. The gel fraction, equilibrium swelling and effect of ph on the swelling percent were also studied. The prepared copolymers were also characterized by FTIR spectral analysis, thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM) techniques. In order to evaluate its controlled release potential, different prepared hydrogels were loaded with KNO 3 as an agrochemical model and its potential for controlled release of KNO 3 was studied and evaluated with respect to different parameters such as time of release, ph of the medium, and temperatures. The results obtained from swelling, loading of KNO 3 , and release behavior studies suggested and recommended the possible use of prepared hydrogels for enhancing the plantation of Linum Usitatissimum.

Molecular Understanding and Structural-Based Design of Polyacrylamides and Polyacrylates as Antifouling Materials.

Science.gov (United States)

Chen, Hong; Zhao, Chao; Zhang, Mingzhen; Chen, Qiang; Ma, Jie; Zheng, Jie

2016-04-12

Design and synthesis of highly bioinert and biocompatible antifouling materials are crucial for a broad range of biomedical and engineering applications. Among antifouling materials, polyacrylamides and polyacrylates have proved so promising because of cheap raw materials, ease of synthesis and applicability, and abundant functional groups. The strong surface hydration and the high surface packing density of polyacrylamides and polyacrylates are considered to be the key contributors to their antifouling property. In this article, we review our studies on the design and synthesis of a series of polyacrylamides and polyacrylates with different molecular structures. These polymers can be fabricated into different architectural forms (brushes, nanoparticles, nanogels, and hydrogels), all of which are highly resistant to the attachment of proteins, cells, and bacteria. We find that small structural changes in the polymers can lead to large enhancement in surface hydration and antifouling performance, both showing a positive correlation. This reveals a general design rule for effective antifouling materials. Furthermore, polyacrylamides and polyacrylates are readily functionalized with other bioactive compounds to achieve different new multifunctionalities.

Effects of polyacrylic acid additive on barium sulfate particle morphology

Energy Technology Data Exchange (ETDEWEB)

Li, Jie; Liu, Dandan; Jiang, Hongkun; Wang, Jun; Jing, Xiaoyan; Chen, Rongrong [Key Laboratory of Superlight Material and Surface Technology of Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Zhu, Wenting [Department of Gastroenterology, Harbin Medical University Cancer Hospital, Harbin 150081 (China); Han, Shihui [Key Laboratory of Superlight Material and Surface Technology of Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); Li, Wanyou [College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001 (China); Wei, Hao, E-mail: weihao7512@126.com [Key Laboratory of Superlight Material and Surface Technology of Ministry of Education, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001 (China); College of Power and Energy Engineering, Harbin Engineering University, Harbin 150001 (China)

2016-06-01

In this paper, polyacrylic acid (PAA) was used as a growth modifier to control micron-sized barium sulfate particles via a simple precipitation reaction between sodium sulfate and barium chloride at ambient temperature. The barium sulfate particles were exhibited various morphologies, such as monodisperse spheres, ellipsoids, rose-like aggregates, etc. To better understand the formation mechanisms of the various morphologies of these particles, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermo-gravimetric analysis (TGA) were employed. It was found that the PAA concentration, pH, and Ba{sup 2+} and SO{sub 4}{sup 2−} ions concentrations were the most important parameters controlling the morphology of the BaSO{sub 4} particles. These parameters affected the BaSO{sub 4} morphology by influencing the interactions between the PAA carboxyl groups and inorganic ions and the conformation change of the PAA molecular chains. Moreover, this work attempts to provide a preliminary understanding of the formation of the spherical BaSO{sub 4} particles with the randomly coiled conformation of the polymer. - Highlights: • Polyacrylic acid (PAA) was used as a growth modifier to control micron-sized BaSO{sub 4} particles. • The PAA/BaSO{sub 4} particles were exhibited various morphologies. • Provide a preliminary understanding of the formation mechanism of BaSO{sub 4} particles.

Preparation and Characterization of Organic-Inorganic Hybrid Hydrogel Electrolyte Using Alkaline Solution

OpenAIRE

Chiku, Masanobu; Tomita, Shoji; Higuchi, Eiji; Inoue, Hiroshi

2011-01-01

Organic-inorganic hybrid hydrogel electrolytes were prepared by mixing hydrotalcite, cross-linked potassium poly(acrylate) and 6 M KOH solution. The organic-inorganic hybrid hydrogel electrolytes had high ionic conductivity (0.456–0.540 S cm−1) at 30 °C. Moreover, the mechanical strength of the hydrogel electrolytes was high enough to form a 2–3 mm thick freestanding membrane because of the reinforcement with hydrotalcite.

Influence of Irradiated Chitosan on Growth and Flower Quality of Gladiolus at Different Sowing Dates and Synthesis of Radiation Cross-Linked Poly(Acrylic Acid) Hydrogel for Agriculture Applications. Chapter 14

Energy Technology Data Exchange (ETDEWEB)

Habib, U.; Ahmed, N. [Department of Horticulture, PMAS Arid Agriculture University, Rawalpindi (Pakistan); Zahid, S.; Yashin, T., E-mail: yasintariq@yahoo.com [Pakistan Institute of Engineering and Applied Sciences, Islamabad (Pakistan)

2014-07-15

The plant growth promoter activity of irradiated chitosan on Gladiolus hortulanus cv. Amsterdam was studied. Chitosan was applied in the form of foliar spray at third leaf stage. Corms were sown at three different dates with 15-day intervals. Data on several parameters such as survival percentage, leaf area, plant height, number of florets per spike, and vase life were collected. Chitosan-treated plants showed superior results as compared to the control samples. Acrylic acid-based superabsorbent hydrogel was prepared using phenyltriethoxysilane (PTES) as cross-linker. Different amounts of PTES were incorporated and irradiated at different doses of up to a maximum of 30 kGy. The cross-linked acrylic acid showed hydrogel properties, and its swelling kinetics, gel fraction, and equilibrium degree of swelling (EDS) were studied. The swelling of hydrogel was also affected by pH, ionic strength, and temperature. These hydrogels can be further explored as a super water absorbent material in semi-arid and drought prone areas. (author)

Enzymatically crosslinked silk-hyaluronic acid hydrogels.

Science.gov (United States)

Raia, Nicole R; Partlow, Benjamin P; McGill, Meghan; Kimmerling, Erica Palma; Ghezzi, Chiara E; Kaplan, David L

2017-07-01

In this study, silk fibroin and hyaluronic acid (HA) were enzymatically crosslinked to form biocompatible composite hydrogels with tunable mechanical properties similar to that of native tissues. The formation of di-tyrosine crosslinks between silk fibroin proteins via horseradish peroxidase has resulted in a highly elastic hydrogel but exhibits time-dependent stiffening related to silk self-assembly and crystallization. Utilizing the same method of crosslinking, tyramine-substituted HA forms hydrophilic and bioactive hydrogels that tend to have limited mechanics and degrade rapidly. To address the limitations of these singular component scaffolds, HA was covalently crosslinked with silk, forming a composite hydrogel that exhibited both mechanical integrity and hydrophilicity. The composite hydrogels were assessed using unconfined compression and infrared spectroscopy to reveal of the physical properties over time in relation to polymer concentration. In addition, the hydrogels were characterized by enzymatic degradation and for cytotoxicity. Results showed that increasing HA concentration, decreased gelation time, increased degradation rate, and reduced changes that were observed over time in mechanics, water retention, and crystallization. These hydrogel composites provide a biologically relevant system with controllable temporal stiffening and elasticity, thus offering enhanced tunable scaffolds for short or long term applications in tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Skin-Inspired Multifunctional Autonomic-Intrinsic Conductive Self-Healing Hydrogels with Pressure Sensitivity, Stretchability, and 3D Printability.

Science.gov (United States)

Darabi, Mohammad Ali; Khosrozadeh, Ali; Mbeleck, Rene; Liu, Yuqing; Chang, Qiang; Jiang, Junzi; Cai, Jun; Wang, Quan; Luo, Gaoxing; Xing, Malcolm

2017-08-01

The advent of conductive self-healing (CSH) hydrogels, a class of novel materials mimicking human skin, may change the trajectory of the industrial process because of their potential applications in soft robots, biomimetic prostheses, and health-monitoring systems. Here, the development of a mechanically and electrically self-healing hydrogel based on physically and chemically cross-linked networks is reported. The autonomous intrinsic self-healing of the hydrogel is attained through dynamic ionic interactions between carboxylic groups of poly(acrylic acid) and ferric ions. A covalent cross-linking is used to support the mechanical structure of the hydrogel. Establishing a fair balance between the chemical and physical cross-linking networks together with the conductive nanostructure of polypyrrole networks leads to a double network hydrogel with bulk conductivity, mechanical and electrical self-healing properties (100% mechanical recovery in 2 min), ultrastretchability (1500%), and pressure sensitivity. The practical potential of CSH hydrogels is further revealed by their application in human motion detection and their 3D-printing performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation and Characterization of Organic-Inorganic Hybrid Hydrogel Electrolyte Using Alkaline Solution

Directory of Open Access Journals (Sweden)

Masanobu Chiku

2011-09-01

Full Text Available Organic-inorganic hybrid hydrogel electrolytes were prepared by mixing hydrotalcite, cross-linked potassium poly(acrylate and 6 M KOH solution. The organic-inorganic hybrid hydrogel electrolytes had high ionic conductivity (0.456–0.540 S cm−1 at 30 °C. Moreover, the mechanical strength of the hydrogel electrolytes was high enough to form a 2–3 mm thick freestanding membrane because of the reinforcement with hydrotalcite.

Poly(AAc-co-MBA) hydrogel films: adhesive and mechanical properties in aqueous medium.

Science.gov (United States)

Arunbabu, Dhamodaran; Shahsavan, Hamed; Zhang, Wei; Zhao, Boxin

2013-01-10

Poly(acrylic acid-co-N,N'-methylenebisacrylamide) hydrogel films were synthesized by copolymerizing acrylic acid (AAc) with N,N'-methylenebisacrylamide (MBA) as a cross-linker via photo polymerization in the spacing confined between two glass plates. NMR spectroscopy was utilized to determine the cross-linking density. We found that the cross-linking density determined by NMR is higher than that expected from the feed concentrations of cross-linkers, suggesting that MBA is more reactive than AAc and the heterogeneous nature of the cross-linking. In addition to the swelling tests, indentation tests were performed on the hydrogel films under water to investigate effects of the cross-linking density on the adhesion and mechanical properties of the hydrogel films in terms of adhesive pull-off force and Hertz-type elastic modulus. As the cross-linker concentration increased, the effective elastic modulus of the hydrogel films increased dramatically at low cross-linking densities and reached a high steady-state value at higher cross-linking densities. The pull-off force decreased with increasing cross-linker concentration and reached a lower force plateau at high cross-linking densities. An optimal "trade-off" cross-linking density was determined to be 0.02 mol fraction of MBA in the hydrogel, where balanced elastic modulus and adhesive pull-off force can be obtained.

Obtention of hydrogels for use as water retainers in soil by gamma irradiation

International Nuclear Information System (INIS)

Burillo, G.; Ogawa, T.

1981-01-01

We have been studying for some time the radiation induced gelation of aqueous polyacrylamide solutions in order to clarify the relationships between the gel structure and gelation conditions. The application of hydrogels as water retainers has been reported previously by some workers and there exist some commercially produced hydrogels in the market, but their costs are not yet satisfactory for use on a large scale in the agricultural region in northern Mexico, where scarcity of water is always the serious problem. In this work, with an aim of obtaining hydrogels most economically, acrylamide, polyethylene oxide, and mixtures of water soluble polymers with acrylamide monomer, were irradiated in solid state under various conditions, in order to find the optimum conditions for gelation and to obtain the hydrogels most suitable as water retainers in soil. The relationships between the gelation, amount of water in the starting materials, molecular weights of polymers, effects of additives and the dose rates, were studied. (author)

Acrylamide in Japanese processed foods and factors affecting acrylamide level in potato chips and tea.

Science.gov (United States)

Yoshida, Mitsuru; Ono, Hiroshi; Chuda, Yoshihiro; Yada, Hiroshi; Ohnishi-Kameyama, Mayumi; Kobayashi, Hidetaka; Ohara-Takada, Akiko; Matsuura-Endo, Chie; Mori, Motoyuki; Hayashi, Nobuyuki; Yamaguchi, Yuichi

2005-01-01

Acrylamide concentrations in processed foods sold in Japanese markets were analyzed by LC-MS/MS and GC-MS methods. Most potato chips and whole potato-based fried snacks showed acrylamide concentration higher than 1000 microg/kg. The concentrations in non-whole potato based Japanese snacks, including rice crackers and candied sweet potatoes, were less tha. 350 microg/kg. Those in instant precooked noodles were less than 100 microg/kg with only one exception. The effect of storage condition of potato tubers on acrylamide concentration in potato chips after frying was also investigated. Sugar content in the tubers increased during cold storage, and the acrylamide concentration increased accordingly. The concentrations of asparagine and other amino acids, however, did not change during the cold storage. High correlations were observed between the acrylamide content in the chips and glucose and fructose contents in the tubers. This fact indicated that the limiting factor for acrylamide formation in potato chips is reducing sugar, not asparagine content in the tubers. Effects of roasting time and temperature on acrylamide concentration in roasted green tea are also described.

Poly(amido-amine)-based hydrogels with tailored mechanical properties and degradation rates for tissue engineering.

Science.gov (United States)

Martello, Federico; Tocchio, Alessandro; Tamplenizza, Margherita; Gerges, Irini; Pistis, Valentina; Recenti, Rossella; Bortolin, Monica; Del Fabbro, Massimo; Argentiere, Simona; Milani, Paolo; Lenardi, Cristina

2014-03-01

Poly(amido-amine) (PAA) hydrogels containing the 2,2-bisacrylamidoacetic acid-4-amminobutyl guanidine monomeric unit have a known ability to enhance cellular adhesion by interacting with the arginin-glycin-aspartic acid (RGD)-binding αVβ3 integrin, expressed by a wide number of cell types. Scientific interest in this class of materials has traditionally been hampered by their poor mechanical properties and restricted range of degradation rate. Here we present the design of novel biocompatible, RGD-mimic PAA-based hydrogels with wide and tunable degradation rates as well as improved mechanical and biological properties for biomedical applications. This is achieved by radical polymerization of acrylamide-terminated PAA oligomers in both the presence and absence of 2-hydroxyethylmethacrylate. The degradation rate is found to be precisely tunable by adjusting the PAA oligomer molecular weight and acrylic co-monomer concentration in the starting reaction mixture. Cell adhesion and proliferation tests on Madin-Darby canine kidney epithelial cells show that PAA-based hydrogels have the capacity to promote cell adhesion up to 200% compared to the control. Mechanical tests show higher compressive strength of acrylic chain containing hydrogels compared to traditional PAA hydrogels. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Injectable hydrogels derived from phosphorylated alginic acid calcium complexes

Energy Technology Data Exchange (ETDEWEB)

Kim, Han-Sem; Song, Minsoo, E-mail: minsoosong00@gmail.com; Lee, Eun-Jung; Shin, Ueon Sang, E-mail: usshin12@dankook.ac.kr

2015-06-01

Phosphorylation of sodium alginate salt (NaAlg) was carried out using H{sub 3}PO{sub 4}/P{sub 2}O{sub 5}/Et{sub 3}PO{sub 4} followed by acid–base reaction with Ca(OAc){sub 2} to give phosphorylated alginic acid calcium complexes (CaPAlg), as a water dispersible alginic acid derivative. The modified alginate derivatives including phosphorylated alginic acid (PAlg) and CaPAlg were characterized by nuclear magnetic resonance spectroscopy for {sup 1}H, and {sup 31}P nuclei, high resolution inductively coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. CaPAlg hydrogels were prepared simply by mixing CaPAlg solution (2 w/v%) with NaAlg solution (2 w/v%) in various ratios (2:8, 4:6, 6:4, 8:2) of volume. No additional calcium salts such as CaSO{sub 4} or CaCl{sub 2} were added externally. The gelation was completed within about 3–40 min indicating a high potential of hydrogel delivery by injection in vivo. Their mechanical properties were tested to be ≤ 6.7 kPa for compressive strength at break and about 8.4 kPa/mm for elastic modulus. SEM analysis of the CaPAlg hydrogels showed highly porous morphology with interconnected pores of width in the range of 100–800 μm. Cell culture results showed that the injectable hydrogels exhibited comparable properties to the pure alginate hydrogel in terms of cytotoxicity and 3D encapsulation of cells for a short time period. The developed injectable hydrogels showed suitable physicochemical and mechanical properties for injection in vivo, and could therefore be beneficial for the field of soft tissue engineering. - Highlights: • Preparation of water-soluble alginic acid complexes with calcium phosphate • Self-assembly of the phosphorylated alginic acid calcium complexes with sodium alginate • Preparation of injectable hydrogels with diverse gelation times within about 3–40 min.

Fabrication of hydrogels with steep stiffness gradients for studying cell mechanical response.

Directory of Open Access Journals (Sweden)

Raimon Sunyer

Full Text Available Many fundamental cell processes, such as angiogenesis, neurogenesis and cancer metastasis, are thought to be modulated by extracellular matrix stiffness. Thus, the availability of matrix substrates having well-defined stiffness profiles can be of great importance in biophysical studies of cell-substrate interaction. Here, we present a method to fabricate biocompatible hydrogels with a well defined and linear stiffness gradient. This method, involving the photopolymerization of films by progressively uncovering an acrylamide/bis-acrylamide solution initially covered with an opaque mask, can be easily implemented with common lab equipment. It produces linear stiffness gradients of at least 115 kPa/mm, extending from ∼1 kPa to 240 kPa (in units of Young's modulus. Hydrogels with less steep gradients and narrower stiffness ranges can easily be produced. The hydrogels can be covalently functionalized with uniform coatings of proteins that promote cell adhesion. Cell spreading on these hydrogels linearly correlates with hydrogel stiffness, indicating that this technique effectively modifies the mechanical environment of living cells. This technique provides a simple approach that produces steeper gradients, wider rigidity ranges, and more accurate profiles than current methods.

Design of a Versatile pH-Responsive Hydrogel for Potential Oral Delivery of Gastric-Sensitive Bioactives

Directory of Open Access Journals (Sweden)

Angus R. Hibbins

2017-09-01

Full Text Available A pH-responsive hydrogel system was prepared by free radical polymerization of acrylamide and methyl acrylic acid in the presence of N-N′-methylene bisacrylamide. Sodium bicarbonate was further applied as a blowing agent, which afforded a porous hydrogel structure. The hydrogel system achieved a constant super swelling rate within simulated intestinal buffer (~4%/min and remained relatively static within simulated gastric buffer (~0.8%/min. The hydrogel system was able to achieve matrix resilience greater than 30% under a relatively high strain of 40%. In addition, the hydrogel system demonstrated significant swelling properties in response to simulated intestinal environmental over 24 h, with contrasting characteristics in simulated gastric buffer. The hydrogel demonstrated type IV isotherm porosity characteristics, with remarkable MRI and SEM variations in gastric and intestinal simulated fluids. Drug loading was observed to be greater than 98% using theophylline as a prototype drug, evaluating its controlled release kinetics over 24 h. The hydrogel exhibited substantial pH-responsive activity, which could be used as a versatile platform for targeted release of gastric-sensitive therapeutics to the small intestine.

Characterization of Lactate Sensors Based on Lactate Oxidase and Palladium Benzoporphyrin Immobilized in Hydrogels

Directory of Open Access Journals (Sweden)

Liam P. Andrus

2015-07-01

Full Text Available An optical biosensor for lactate detection is described. By encapsulating enzyme-phosphor sensing molecules within permeable hydrogel materials, lactate-sensitive emission lifetimes were achieved. The relative amount of monomer was varied to compare three homo- and co-polymer materials: poly(2-hydroxyethyl methacrylate (pHEMA and two copolymers of pHEMA and poly(acrylamide (pAam. Diffusion analysis demonstrated the ability to control lactate transport by varying the hydrogel composition, while having a minimal effect on oxygen diffusion. Sensors displayed the desired dose-variable response to lactate challenges, highlighting the tunable, diffusion-controlled nature of the sensing platform. Short-term repeated exposure tests revealed enhanced stability for sensors comprising hydrogels with acrylamide additives; after an initial “break-in” period, signal retention was 100% for 15 repeated cycles. Finally, because this study describes the modification of a previously developed glucose sensor for lactate analysis, it demonstrates the potential for mix-and-match enzyme-phosphor-hydrogel sensing for use in future multi-analyte sensors.

Enzymatic Inverse Opal Hydrogel Particles for Biocatalyst.

Science.gov (United States)

Wang, Huan; Gu, Hongcheng; Chen, Zhuoyue; Shang, Luoran; Zhao, Ze; Gu, Zhongze; Zhao, Yuanjin

2017-04-19

Enzymatic carriers have a demonstrated value for chemical reactions and industrial applications. Here, we present a novel kind of inverse opal hydrogel particles as the enzymatic carriers. The particles were negatively replicated from spherical colloidal crystal templates by using magnetic nanoparticles tagged acrylamide hydrogel. Thus, they were endowed with the features of monodispersity, small volume, complete penetrating structure, and controllable motion, which are all beneficial for improving the efficiency of biocatalysis. In addition, due to the ordered porous nanostructure, the inverse opal hydrogel particles were imparted with unique photonic band gaps (PBGs) and vivid structural colors for encoding varieties of immobilized enzymes and for constructing a multienzymes biocatalysis system. These features of the inverse opal hydrogel particles indicate that they are ideal enzymatic carriers for biocatalysis.

Investigation on Au-nano incorporated pH-sensitive (itaconic acid/acrylic acid/triethylene glycol) based polymeric biocompatible hydrogels

Energy Technology Data Exchange (ETDEWEB)

Sakthivel, M., E-mail: msakthi81986@gmail.com [Research and Development Centre, Bharathiar University, Coimbatore 641 046, Tamilnadu (India); Department of Chemistry, Ganadipathy Tulsi' s Jain Engineering College, Kaniyambadi, Vellore 632 102, Tamilnadu (India); Franklin, D.S., E-mail: loyolafrank@yahoo.co.in [Department of Chemistry, C. Abdul Hakeem College of Engineering and Technology, Melvisharam 632509, Tamilnadu (India); Sudarsan, S., E-mail: srsudarsan29@gmail.com [Department of Chemistry, Periyar University, Salem 636011, Tamilnadu (India); Chitra, G., E-mail: chitramuralikrishnan@gmail.com [Department of Chemistry, Periyar University, Salem 636011, Tamilnadu (India); Guhanathan, S., E-mail: sai_gugan@yahoo.com [PG & Research Department of Chemistry, Muthurangam Government Arts College, Vellore 632 002, Tamilnadu (India)

2017-06-01

The pH-sensitive gold nano hydrogel based on itaconic acid, acrylic acid and triethylene glycol (GIAT) has been prepared by free radical polymerization viz. organic solventless approach with different monomer ratios. The nature of bonding and structural identification of GIAT hydrogels were characterized by FT-IR spectroscopy. The surface morphology of gold gel was examined using scanning electron microscopy (SEM). In addition, transmission electron microscopy (TEM) was used to identify the size of gold nano particles. The in vitro biocompatibility of GIAT hydrogel has been evaluated in 3T3 fibroblast cell lines. The obtained results show that gold nano particle incorporated hydrogel possess ~ 99% of cell proliferation. Followed by, the impact of gold nano particles on swelling, surface morphology was studied. The consecutive preparation of hydrogel, effect of different pH conditions, and stoichiometry of monomeric units have also been discussed. The degree of swelling was measured in carbonate buffer solutions for 24 h period with varying pH such as 1.2, 6.0, 7.4 and 10.0. The obtained results showed that the stoichiometry of itaconic acid and gold nano particles plays an essential role in modifying the nature of GIAT polymeric hydrogels. In conclusion, promising Au-nano incorporated pH-sensitive bio polymeric hydrogels were prepared and characterized. The unique properties of these Au-nano hydrogel make them attractive use in biomedical applications. - Highlights: • Itaconic acid based hydrogels were developed viz. greener organic solvent less approach. • The enhanced equilibrium swelling at acidic and basic medium was observed for nano-Au-incorporated nano composite hydrogels. • The prepared GIAT hydrogel showed ~ 99% of cell proliferation. • This kind of pH-sensitive polymeric hydrogels may be useful for controlled drug delivery system.

Investigation on Au-nano incorporated pH-sensitive (itaconic acid/acrylic acid/triethylene glycol) based polymeric biocompatible hydrogels

International Nuclear Information System (INIS)

Sakthivel, M.; Franklin, D.S.; Sudarsan, S.; Chitra, G.; Guhanathan, S.

2017-01-01

The pH-sensitive gold nano hydrogel based on itaconic acid, acrylic acid and triethylene glycol (GIAT) has been prepared by free radical polymerization viz. organic solventless approach with different monomer ratios. The nature of bonding and structural identification of GIAT hydrogels were characterized by FT-IR spectroscopy. The surface morphology of gold gel was examined using scanning electron microscopy (SEM). In addition, transmission electron microscopy (TEM) was used to identify the size of gold nano particles. The in vitro biocompatibility of GIAT hydrogel has been evaluated in 3T3 fibroblast cell lines. The obtained results show that gold nano particle incorporated hydrogel possess ~ 99% of cell proliferation. Followed by, the impact of gold nano particles on swelling, surface morphology was studied. The consecutive preparation of hydrogel, effect of different pH conditions, and stoichiometry of monomeric units have also been discussed. The degree of swelling was measured in carbonate buffer solutions for 24 h period with varying pH such as 1.2, 6.0, 7.4 and 10.0. The obtained results showed that the stoichiometry of itaconic acid and gold nano particles plays an essential role in modifying the nature of GIAT polymeric hydrogels. In conclusion, promising Au-nano incorporated pH-sensitive bio polymeric hydrogels were prepared and characterized. The unique properties of these Au-nano hydrogel make them attractive use in biomedical applications. - Highlights: • Itaconic acid based hydrogels were developed viz. greener organic solvent less approach. • The enhanced equilibrium swelling at acidic and basic medium was observed for nano-Au-incorporated nano composite hydrogels. • The prepared GIAT hydrogel showed ~ 99% of cell proliferation. • This kind of pH-sensitive polymeric hydrogels may be useful for controlled drug delivery system.

Polymerization of acrylamide initiated with Ce(IV- and KMnO4–mercaptosuccinic acid redox systems in acid-aqueous medium

Directory of Open Access Journals (Sweden)

2007-03-01

Full Text Available By using mercaptosuccinic acid-cerium(IV sulfate and mercaptosuccinic acid-KMnO4 redox systems in acid aqueous medium, the polymerization of acrylamide monomer was performed at room temperatures. Water soluble acrylamide polymers which contain mercaptosuccinic acid end-groups were synthesized. The dependence of polymerization yield and the molecular weight of polymer on the initiator concentration(nMSA=nCe(IV at different acid concentrations, polymerization time, temperature, and concentration of sulfuric acid was investigated. The decrease in the initiator concentration resulted in an increase in the molecular weights but a decrease in the yield. The increase of reaction temperature from 20 to 60°C resulted in an increase in the molecular weights and slight decrease of the yield of polymer. Cerium and manganese ions are reduced to Ce(III and Mn(II ions respectively in polymerization reaction. The existence of Ce(III ion bound to polymer was investigated by UV-visible spectrometry and fluorescence measurements. The amount of Mn(II which is incorporated to the polymer was determined.

Antimicrobial activity of poly(acrylic acid) block copolymers

Energy Technology Data Exchange (ETDEWEB)

Gratzl, Günther, E-mail: guenther.gratzl@jku.at [Johannes Kepler University Linz, Institute for Chemical Technology of Organic Materials, Altenberger Str. 69, 4040 Linz (Austria); Paulik, Christian [Johannes Kepler University Linz, Institute for Chemical Technology of Organic Materials, Altenberger Str. 69, 4040 Linz (Austria); Hild, Sabine [Johannes Kepler University Linz, Institute of Polymer Science, Altenberger Str. 69, 4040 Linz (Austria); Guggenbichler, Josef P.; Lackner, Maximilian [AMiSTec GmbH and Co. KG, Leitweg 13, 6345 Kössen, Tirol (Austria)

2014-05-01

The increasing number of antibiotic-resistant bacterial strains has developed into a major health problem. In particular, biofilms are the main reason for hospital-acquired infections and diseases. Once formed, biofilms are difficult to remove as they have specific defense mechanisms against antimicrobial agents. Antimicrobial surfaces must therefore kill or repel bacteria before they can settle to form a biofilm. In this study, we describe that poly(acrylic acid) (PAA) containing diblock copolymers can kill bacteria and prevent from biofilm formation. The PAA diblock copolymers with poly(styrene) and poly(methyl methacrylate) were synthesized via anionic polymerization of tert-butyl acrylate with styrene or methyl methacrylate and subsequent acid-catalyzed hydrolysis of the tert-butyl ester. The copolymers were characterized via nuclear magnetic resonance spectroscopy (NMR), size-exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), elemental analysis, and acid–base titrations. Copolymer films with a variety of acrylic acid contents were produced by solvent casting, characterized by atomic force microscopy (AFM) and tested for their antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The antimicrobial activity of the acidic diblock copolymers increased with increasing acrylic acid content, independent of the copolymer-partner, the chain length and the nanostructure. - Highlights: • Acrylic acid diblock copolymers are antimicrobially active. • The antimicrobial activity depends on the acrylic acid content in the copolymer. • No salts, metals or other antimicrobial agents are needed.

Antimicrobial activity of poly(acrylic acid) block copolymers

International Nuclear Information System (INIS)

Gratzl, Günther; Paulik, Christian; Hild, Sabine; Guggenbichler, Josef P.; Lackner, Maximilian

2014-01-01

The increasing number of antibiotic-resistant bacterial strains has developed into a major health problem. In particular, biofilms are the main reason for hospital-acquired infections and diseases. Once formed, biofilms are difficult to remove as they have specific defense mechanisms against antimicrobial agents. Antimicrobial surfaces must therefore kill or repel bacteria before they can settle to form a biofilm. In this study, we describe that poly(acrylic acid) (PAA) containing diblock copolymers can kill bacteria and prevent from biofilm formation. The PAA diblock copolymers with poly(styrene) and poly(methyl methacrylate) were synthesized via anionic polymerization of tert-butyl acrylate with styrene or methyl methacrylate and subsequent acid-catalyzed hydrolysis of the tert-butyl ester. The copolymers were characterized via nuclear magnetic resonance spectroscopy (NMR), size-exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), elemental analysis, and acid–base titrations. Copolymer films with a variety of acrylic acid contents were produced by solvent casting, characterized by atomic force microscopy (AFM) and tested for their antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The antimicrobial activity of the acidic diblock copolymers increased with increasing acrylic acid content, independent of the copolymer-partner, the chain length and the nanostructure. - Highlights: • Acrylic acid diblock copolymers are antimicrobially active. • The antimicrobial activity depends on the acrylic acid content in the copolymer. • No salts, metals or other antimicrobial agents are needed

Effect of Interferon, Polyacrylic Acid, and Polymethacrylic Acid on Tail Lesions in Mice Infected with Vaccinia Virus

Science.gov (United States)

De Clercq, E.; De Somer, P.

1968-01-01

Intravenous inoculation of mice with vaccinia virus produced characteristic lesions of the tail surface which were suppressed by intraperitoneal administration of interferon and polyacrylic acid (PAA). Polymethacrylic acid (PMAA) stimulated the formation of vaccinia virus lesions. For full activity, both interferon and PAA must be given prior to infection. PAA was still significantly effective at small dose levels (3 mg/kg) and achieved protection for at least 4 weeks. Protection increased with increasing molecular weight of the polymer. The mode of action of PAA is discussed. PMID:5676405

Poly(acrylic acid) modifying bentonite with in-situ polymerization for removing lead ions.

Science.gov (United States)

He, Y F; Zhang, L; Yan, D Z; Liu, S L; Wang, H; Li, H R; Wang, R M

2012-01-01

In this paper, a new kind of poly(acrylic acid) modified clay adsorbent, the poly(acrylic acid)/bentonite composite (PAA/HB) was prepared by in-situ polymerization, and utilized to remove lead(II) ions from solutions. The maximum adsorption of adsorbent is at pH 5 for metal ions, whereas the adsorption starts at pH 2. The effects of contact time (5-60 min), initial concentration of metal ions (200-1,000 mg/L) and adsorbent dosage (0.04-0.12 g/100 mL) have been reported in this article. The experimental data were investigated by means of kinetic and equilibrium adsorption isotherms. The kinetic data were analyzed by the pseudo-first-order and pseudo-second-order equation. The experimental data fitted the pseudo-second-order kinetic model very well. Langmuir and Freundlich isotherms were tried for the system to better understand the adsorption isotherm process. The maximal adsorption capacity of the lead(II) ions on the PAA/HB, as calculated from the Langmuir model, was 769.2 mg/g. The results in this study indicated that PAA/HB was an attractive candidate for removing lead(II) (99%).

Biomimetic Hydrogel Composites for Soil Stabilization and Contaminant Mitigation.

Science.gov (United States)

Zhao, Zhi; Hamdan, Nasser; Shen, Li; Nan, Hanqing; Almajed, Abdullah; Kavazanjian, Edward; He, Ximin

2016-11-15

We have developed a novel method to synthesize a hyper-branched biomimetic hydrogel network across a soil matrix to improve the mechanical strength of the loose soil and simultaneously mitigate potential contamination due to excessive ammonium. This method successfully yielded a hierarchical structure that possesses the water retention, ion absorption, and soil aggregation capabilities of plant root systems in a chemically controllable manner. Inspired by the robust organic-inorganic composites found in many living organisms, we have combined this hydrogel network with a calcite biomineralization process to stabilize soil. Our experiments demonstrate that poly(acrylic acid) (PAA) can work synergistically with enzyme-induced carbonate precipitation (EICP) to render a versatile, high-performance soil stabilization method. PAA-enhanced EICP provides multiple benefits including lengthening of water supply time, localization of cementation reactions, reduction of harmful byproduct ammonium, and achievement of ultrahigh soil strength. Soil crusts we have obtained can sustain up to 4.8 × 10 3 kPa pressure, a level comparable to cementitious materials. An ammonium removal rate of 96% has also been achieved. These results demonstrate the potential for hydrogel-assisted EICP to provide effective soil improvement and ammonium mitigation for wind erosion control and other applications.

Charge-discharge characteristics of nickel/zinc battery with polymer hydrogel electrolyte

Energy Technology Data Exchange (ETDEWEB)

Iwakura, Chiaki; Murakami, Hiroki; Nohara, Shinji; Furukawa, Naoji; Inoue, Hiroshi [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan)

2005-12-01

A new nickel/zinc (Ni/Zn) battery was assembled by using polymer hydrogel electrolyte prepared from cross-linked potassium poly(acrylate) and KOH aqueous solution, and its charge-discharge characteristics were investigated. The experimental Ni/Zn cell with the polymer hydrogel electrolyte exhibited well-defined charge-discharge curves and remarkably improved charge-discharge cycle performance, compared to that with a KOH aqueous solution. Moreover, it was found that dendritic growth hardly occurred on the zinc electrode surface during charge-discharge cycles in the polymer hydrogel electrolyte. These results indicate that the polymer hydrogel electrolyte can successfully be used in Ni/Zn batteries as an electrolyte with excellent performance. (author)

Charge-discharge characteristics of nickel/zinc battery with polymer hydrogel electrolyte

Science.gov (United States)

Iwakura, Chiaki; Murakami, Hiroki; Nohara, Shinji; Furukawa, Naoji; Inoue, Hiroshi

A new nickel/zinc (Ni/Zn) battery was assembled by using polymer hydrogel electrolyte prepared from cross-linked potassium poly(acrylate) and KOH aqueous solution, and its charge-discharge characteristics were investigated. The experimental Ni/Zn cell with the polymer hydrogel electrolyte exhibited well-defined charge-discharge curves and remarkably improved charge-discharge cycle performance, compared to that with a KOH aqueous solution. Moreover, it was found that dendritic growth hardly occurred on the zinc electrode surface during charge-discharge cycles in the polymer hydrogel electrolyte. These results indicate that the polymer hydrogel electrolyte can successfully be used in Ni/Zn batteries as an electrolyte with excellent performance.

Synthesis and characterization of biodegradable poly (ethylene glycol) and poly (caprolactone diol) end capped poly (propylene fumarate) cross linked amphiphilic hydrogel as tissue engineering scaffold material.

Science.gov (United States)

Krishna, Lekshmi; Jayabalan, Muthu

2009-12-01

Biodegradable poly (caprolactone diol-co-propylene fumarate-co-ethylene glycol) amphiphilic polymer with poly (ethylene glycol) and poly (caprolactone diol) chain ends (PCL-PPF-PEG) was prepared. PCL-PPF-PEG undergoes fast setting with acrylamide (aqueous solution) by free radical polymerization and produces a crosslinked hydrogel. The cross linked and freeze-dried amphiphilic material has porous and interconnected network. It undergoes higher degree of swelling and water absorption to form hydrogel with hydrophilic and hydrophobic domains at the surface and appreciable tensile strength. The present hydrogel is compatible with L929 fibroblast cells. PCL-PPF-PEG/acrylamide hydrogel is a candidate scaffold material for tissue engineering applications.

Influence of Surfactant Sorbitan Monolaurate to Suspension Polymerization of Polyacrylic Acid Super absorbent

International Nuclear Information System (INIS)

Dewi Sondari; Nuri Astrini; Lik Anah; Agus Haryono

2008-01-01

A super absorbent polymer has been prepared by suspension polymerization reaction using acrylic acid, sodium hydroxide, cyclohexane, potassium persulfate as initiator and sorbitan monolaurate as surfactant. The effect of different weight ratio of acrylic acid/sorbitan monolaurate 20/1, 20/2 and 20/3 were investigated based on its swelling properties, chemical structure by using Fourier Transform-Infra Red (FTIR) Spectroscopy and the surface morphology by scanning electron microscopy (SEM). The molecular weight of polyacrylic acid super absorbent was determinate by intrinsic viscosity measurements in 2 M aqueous sodium hydroxide at 25 o C. The study showed sample with weight ratio of acrylic acid/sorbitan monolaurate = 20/2 have best swelling properties. (author)

Ionizing radiation in the field of hydrogels used for agriculture and medicine

International Nuclear Information System (INIS)

Radoiu, M.; Martin, D.; Oproiu, C.; Indreias, I; Toma, M.; Dragusin, M.; Moraru, R.; Manea, A.

1998-01-01

The hydrogels, such as homopolymers of acrylamide (AHH type), co-polymers of acrylamide-sodium acrylate (ANACH type) and homopolymers of sodium acrylate (NAHH type), obtained by gamma ray and accelerated electron beam are presented. The effects of the solution chemical composition, swelling medium nature, radiation absorbed dose and radiation absorbed dose rate upon the swelling degree and mechanical strength of these hydrogel types are discussed. Distilled water, physiological serum and 4 N NaCl aqueous solution were used as swelling medium. Radiation absorbed dose has an important effect upon the swelling degree of AHH and ANACH types especially when distilled water is used as swelling medium while the NAHH swelling degree presents a small dependence versus absorbed dose for all swelling medium types. Usually, the swelling degree for all hydrogel types decreases versus absorbed dose and absorbed dose rate and exhibits the higher values for distilled water as swelling medium. The hydrogels mechanical strength exhibits a maximum value versus absorbed dose. The best values for mechanical strength depend on hydrogel type and swelling medium. The used range for absorbed dose was from 2 kGy to 16 kGy. Our types of hydrogels were developed for some applications such as in agriculture (AHH and ANACH types) to maintain soil humidity and in medicine as absorption material for dressing (NAHH types). (author)

Oral delivery of insulin using pH-sensitive hydrogels based on polyvinyl alcohol grafted with acrylic acid/methacrylic acid by radiation

Energy Technology Data Exchange (ETDEWEB)

Nho, Young-Chang [Radiation Application Research Division, Korea Atomic Energy Research Institute, Daejeon 305-600 (Korea, Republic of)]. E-mail: ycnho@kaeri.re.kr; Park, Sung-Eun [Radiation Application Research Division, Korea Atomic Energy Research Institute, Daejeon 305-600 (Korea, Republic of); Kim, Hyung-Il [College of Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Hwang, Taek-Sung [College of Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

2005-07-01

The pH-responsive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing in the small intestine. Hydrogels based on poly(vinyl alcohol) networks grafted with acrylic acid or methacrylic acid were prepared via a two-step process. Poly(vinyl alcohol) hydrogels were prepared by gamma ray irradiation (50 kGy) and then followed by grafting either acrylic acid or methacrylic acid onto this poly(vinyl alcohol) hydrogels with subsequent irradiation (5-20 kGy). These graft hydrogels showed pH-sensitive swelling behavior. These hydrogels were used as carrier for the controlled release of insulin. The in vitro release of insulin was observed for the insulin-loaded hydrogels in a simulated intestinal fluid (pH 6.8) but not in a simulated gastric fluid (pH 1.2). The release behavior of insulin in vivo in a rat model confirmed the effectiveness of the oral delivery of insulin to control the level of glucose.

Oral delivery of insulin using pH-sensitive hydrogels based on polyvinyl alcohol grafted with acrylic acid/methacrylic acid by radiation

International Nuclear Information System (INIS)

Nho, Young-Chang; Park, Sung-Eun; Kim, Hyung-Il; Hwang, Taek-Sung

2005-01-01

The pH-responsive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing in the small intestine. Hydrogels based on poly(vinyl alcohol) networks grafted with acrylic acid or methacrylic acid were prepared via a two-step process. Poly(vinyl alcohol) hydrogels were prepared by gamma ray irradiation (50 kGy) and then followed by grafting either acrylic acid or methacrylic acid onto this poly(vinyl alcohol) hydrogels with subsequent irradiation (5-20 kGy). These graft hydrogels showed pH-sensitive swelling behavior. These hydrogels were used as carrier for the controlled release of insulin. The in vitro release of insulin was observed for the insulin-loaded hydrogels in a simulated intestinal fluid (pH 6.8) but not in a simulated gastric fluid (pH 1.2). The release behavior of insulin in vivo in a rat model confirmed the effectiveness of the oral delivery of insulin to control the level of glucose

Water absorbency of chitosan grafted acrylic acid hydrogels

Science.gov (United States)

Astrini, N.; Anah, L.; Haryono, A.

2017-07-01

Acrylic acid (AA) monomer was directly grafted onto chitosan (CTS) using potassium persulfate (KPS) as an initiator and methylenebisacrylamide (MBA) as a crosslinking agent under an inert atmosphere. One factor affecting the swelling capacity of the obtained hydrogel, KPS concentration, were studied. The hydrogel products were characterized using Fourier Transform Infrared spectroscopy (FTIR) for chemical structure and scanning electron microscopy (SEM) for morphology. Swelling of the hydrogel samples in distilled water and saline solution ( 9% NaCl ) was examined. Swelling capacity of the CTS-g-PAA hydrogels in distilled water (88.53 g/g) was higher than in NaCl solution (29.94 g/g) The highest swelling capacity value was obtained when the grafted reaction was carried out using 2.5wt% initiator

Preparation and physico-chemical properties of hydrogels from carboxymethyl cassava starch crosslinked with citric acid

Science.gov (United States)

Boonkham, Sasikan; Sangseethong, Kunruedee; Chatakanon, Pathama; Niamnuy, Chalida; Nakasaki, Kiyohiko; Sriroth, Klanarong

2014-06-01

Recently, environmentally friendly hydrogels prepared from renewable bio-based resources have drawn significant attention from both industrial and academic sectors. In this study, chemically crosslinked hydrogels have been developed from cassava starch which is a bio-based polymer using a non-toxic citric acid as a crosslinking agent. Cassava starch was first modified by carboxymethylation to improve its water absorbency property. The carboxymethyl cassava starch (CMCS) obtained was then crosslinked with citric acid at different concentrations and reaction times. The gel fraction of hydrogels increased progressively with increasing citric acid concentration. Free swelling capacity of hydrogels in de-ionized water, saline solution and buffers at various pHs as well as absorption under load were investigated. The results revealed that swelling behavior and mechanical characteristic of hydrogels depended on the citric acid concentration used in reaction. Increasing citric acid concentration resulted in hydrogels with stronger network but lower swelling and absorption capacity. The cassava starch hydrogels developed were sensitive to ionic strength and pH of surrounding medium, showing much reduced swelling capacity in saline salt solution and acidic buffers.

Synthesis and property characterization of cassava starch grafted poly(acrylamide-co-(maleic acid)) superabsorbent via γ-irradiation

International Nuclear Information System (INIS)

Kiatkamjornwong, Suda; Mongkolsawat, Kanlaya; Sonsuk, Manit

2004-01-01

Graft copolymerizations of acrylamide and maleic acid onto cassava starch by a simultaneous irradiation technique using γ-rays as a initiator were carried out. Various important parameters of total dose, dose rate, monomer-to-cassava starch ratio and maleic acid content were studied. Addition of 2% ww -1 diprotic acid of maleic acid into the reaction mixture yields a saponified starch graft copolymer with a water absorption in distilled water as high as 2256g g -1 of its dried weight. The water absorption of these saponified graft copolymers insaline and buffer solutions was also measured. The water absorption depends largely on the cationic type and concentration of these solutions in terms of ionic strength. This research explains a charge transfer mechanism for graft copolymerization of maleic acid and acrylamide onto cassava starch, and describes the influential parameters that affect grafting efficiency and water absorption. (author)

A novel multi-responsive polyampholyte composite hydrogel with excellent mechanical strength and rapid shrinking rate.

Science.gov (United States)

Xu, Kun; Tan, Ying; Chen, Qiang; An, Huiyong; Li, Wenbo; Dong, Lisong; Wang, Pixin

2010-05-15

Series of hydrophilic core-shell microgels with cross-linked poly(N-isopropylacrylamide) (PNIPAAm) as core and poly(vinyl amine) (PVAm) as shell are synthesized via surfactant-free emulsion polymerization. Then, the microgels are treated with a small amount of potassium persulfate (KPS) to generate free radicals on the amine nitrogens of PVAm, which subsequently initiate the graft copolymerization of acrylic acid (AA), acryloyloxyethyl trimethyl ammonium chloride (DAC), and acrylamide (AAm) onto microgels to prepare multi-responsive composite hydrogels. The composite hydrogels consist of cross-linked ungrafted polyampholyte chains as the first network and microgels with grafted polyampholyte chains as graft point and second network and show surprising mechanical strength and rapid response rate. The investigation shows the compress strength of composite hydrogels is up to 17-30 MPa, which is 60-100 times higher than that of the hydrogel matrix. The composite hydrogel shows reversible switch of transmittance when traveling the lowest critical temperature (LCST) of microgels. When the composite hydrogel swollen in pH 2.86 solution at ambient condition is immersed into the pH 7.00 solution at 45 °C, a rapid dynamic shrinking can be observed. And the character time (τ) of shrinking dynamic of composite hydrogel is 251.9 min, which is less than that of hydrogel matrix (τ=2273.7 min). Copyright © 2010 Elsevier Inc. All rights reserved.

Synthesis and characterization of hyaluronic acid/human-like collagen hydrogels

International Nuclear Information System (INIS)

Zhang, Jingjing; Ma, Xiaoxuan; Fan, Daidi; Zhu, Chenhui; Deng, Jianjun; Hui, Junfeng; Ma, Pei

2014-01-01

Injectable hydrogel plays an important role in soft tissue filling and repair. We report an injectable hydrogel based on hyaluronic acid (HA) and human-like collagen (HLC), both with favorable biocompatibility and biodegradability. These two types of biomacromolecules were crosslinked with 1,4-butanediol diglycidyl ether to form a three-dimensional network. The redundant crosslinker was removed by dialysis and distillation. An HA-based hydrogel prepared by the same method was used as a control. The cytocompatibility was studied with a Cell Counting Kit-8 (CCK-8) test. Carbazole colorimetry was used to analyze the in vitro degradation rate. The histocompatibility was evaluated by hematoxylin and eosin (H and E) staining analysis and immunohistochemical analysis. The CCK-8 assay demonstrated that the HA/HLC hydrogel was less cytotoxic than the HA-based hydrogel and could promote baby hamster kidney cell (BHK) proliferation. The cell adhesion indicated that BHK could grow well on the surface of the materials and maintain good cell viability. The in vitro degradation test showed that the HA/HLC hydrogel had a longer degradation time and an excellent antienzyme ability. In vivo injection showed that there was little inflammatory response to HA/HLC after 1, 2, and 4 weeks. Therefore, the HA/HLC hydrogel is a promising biomaterial for soft tissue filling and repair. - Highlights: • Human-like collagen was used with hyaluronic acid to prepare soft tissue filling meterials. • 1,4-Butanediol diglycidyl ether (BDDE) was introduced to treat the hydrogels. • The addition of human-like collagen could improve the biological properties of hydrogels

Synthesis and characterization of hyaluronic acid/human-like collagen hydrogels

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jingjing; Ma, Xiaoxuan, E-mail: xiaoxuanma@163.com; Fan, Daidi, E-mail: fandaidi@nwu.edu.cn; Zhu, Chenhui; Deng, Jianjun; Hui, Junfeng; Ma, Pei

2014-10-01

Injectable hydrogel plays an important role in soft tissue filling and repair. We report an injectable hydrogel based on hyaluronic acid (HA) and human-like collagen (HLC), both with favorable biocompatibility and biodegradability. These two types of biomacromolecules were crosslinked with 1,4-butanediol diglycidyl ether to form a three-dimensional network. The redundant crosslinker was removed by dialysis and distillation. An HA-based hydrogel prepared by the same method was used as a control. The cytocompatibility was studied with a Cell Counting Kit-8 (CCK-8) test. Carbazole colorimetry was used to analyze the in vitro degradation rate. The histocompatibility was evaluated by hematoxylin and eosin (H and E) staining analysis and immunohistochemical analysis. The CCK-8 assay demonstrated that the HA/HLC hydrogel was less cytotoxic than the HA-based hydrogel and could promote baby hamster kidney cell (BHK) proliferation. The cell adhesion indicated that BHK could grow well on the surface of the materials and maintain good cell viability. The in vitro degradation test showed that the HA/HLC hydrogel had a longer degradation time and an excellent antienzyme ability. In vivo injection showed that there was little inflammatory response to HA/HLC after 1, 2, and 4 weeks. Therefore, the HA/HLC hydrogel is a promising biomaterial for soft tissue filling and repair. - Highlights: • Human-like collagen was used with hyaluronic acid to prepare soft tissue filling meterials. • 1,4-Butanediol diglycidyl ether (BDDE) was introduced to treat the hydrogels. • The addition of human-like collagen could improve the biological properties of hydrogels.

Enhanced adsorption of methyl violet and congo red by using semi and full IPN of polymethacrylic acid and chitosan.

Science.gov (United States)

Maity, Jayabrata; Ray, Samit Kumar

2014-04-15

Semi and full interpenetrating polymer network (IPN) type hydrogels were prepared by free radical in situ polymerization of methacrylic acid in presence of chitosan using N,N'-methylene-bis-acrylamide (MBA) and glutaraldehyde (for full IPN) as crosslinker. Several semi and full IPN type hydrogels were prepared by varying initiator and crosslinker concentration and also monomer to chitosan mass ratio. These hydrogels were characterized and used for removal of methyl violet and congo red dye from water. Isotherms and kinetics of dye adsorption were also evaluated. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ibuprofen-conjugated hyaluronate/polygalacturonic acid hydrogel for the prevention of epidural fibrosis.

Science.gov (United States)

Lin, Cheng-Yi; Peng, Hsiu-Hui; Chen, Mei-Hsiu; Sun, Jui-Sheng; Chang, Chih-Ju; Liu, Tse-Ying; Chen, Ming-Hong

2016-05-01

The formation of fibrous tissue is part of the natural healing response following a laminectomy. Severe scar tissue adhesion, known as epidural fibrosis, is a common cause of failed back surgery syndrome. In this study, by combining the advantages of drug treatment with a physical barrier, an ibuprofen-conjugated crosslinkable polygalacturonic acid and hyaluronic acid hydrogel was developed for epidural fibrosis prevention. Conjugation was confirmed and measured by 1D(1)H NMR spectroscopy.In vitroanalysis showed that the ibuprofen-conjugated polygalacturonic acid-hyaluronic acid hydrogel showed low cytotoxicity. In addition, the conjugated ibuprofen decreased prostaglandin E2production of the lipopolysaccharide-induced RAW264.7 cells. Histological data inin vivostudies indicated that the scar tissue adhesion of laminectomized male adult rats was reduced by the application of our ibuprofen-conjugated polygalacturonic acid-hyaluronic acid hydrogel. Its use also reduced the population of giant cells and collagen deposition of scar tissue without inducing extensive cell recruitment. The results of this study therefore suggest that the local delivery of ibuprofenviaa polygalacturonic acid-hyaluronic acid-based hydrogel reduces the possibility of epidural fibrosis. © The Author(s) 2016.

Development of thiolated poly(acrylic acid) microparticles for the nasal administration of exenatide.

Science.gov (United States)

Millotti, Gioconda; Vetter, Anja; Leithner, Katharina; Sarti, Federica; Shahnaz Bano, Gul; Augustijns, Patrick; Bernkop-Schnürch, Andreas

2014-12-01

The purpose of this study was to develop a microparticulate formulation for nasal delivery of exenatide utilizing a thiolated polymer. Poly(acrylic acid)-cysteine (PAA-cys) and unmodified PAA microparticles loaded with exenatide were prepared via coprecipitation of the drug and the polymer followed by micronization. Particle size, drug load and release of incorporated exenatide were evaluated. Permeation enhancing properties of the formulations were investigated on excised porcine respiratory mucosa. The viability of the mucosa was investigated by histological studies. Furthermore, ciliary beat frequency (CBF) studies were performed. Microparticles displayed a mean size of 70-80 µm. Drug encapsulation was ∼80% for both thiolated and non-thiolated microparticles. Exenatide was released from both thiolated and non-thiolated particles in comparison to exenatide in buffer only within 40 min. As compared to exenatide dissolved in buffer only, non-thiolated and thiolated microparticles resulted in a 2.6- and 4.7-fold uptake, respectively. Histological studies performed before and after permeation studies showed that the mucosa is not damaged during permeation studies. CBF studies showed that the formulations were cilio-friendly. Based on these results, poly(acrylic acid)-cysteine-based microparticles seem to be a promising approach starting point for the nasal delivery of exenatide.

Silver incorporated polypyrrole/polyacrylic acid electrode for electrochemical supercapacitor

Science.gov (United States)

Patil, Dipali S.; Pawar, Sachin A.; Kamble, Archana S.; Patil, Pramod S.

2013-06-01

In the present work, we study Ag doping effect on the specific capacitance of Polypyrrole/Polyacrylic Acid (PPy/PAA). Ag incorporated films were prepared by simple chemical route. Fourier transform-infrared and Fourier transform-Raman techniques were used for the phase identification. Surface morphology of the films was examined by Field Emission scanning electron microscopy and revealed granular structure for PPY, attached granules for PPy/PAA and granules with bright spots of Ag particles for the PPy/PAA/Ag films. The supercapacitive behavior of the electrodes was tested in three electrode system with 0.1 M H2SO4 electrolyte by using cyclic voltammetry. The highest specific capacitance value 226 Fg-1 was observed for the PPy/PAA/Ag film.

Synthesis of luminescent YVO4:Eu3+ submicrometer crystals through hydrogels as directing agents

International Nuclear Information System (INIS)

Li, Yan; Zheng, Yuhui; Wang, Qianming; Zhang, Cheng Cheng

2012-01-01

The innovative hydrogel template (polyacrylamide or polyacrylic acid) directed synthesis of YVO 4 :Eu 3+ phosphor in a controlled manner was thoroughly studied. Photoluminescence spectra show the europium(III)-doped yttrium orthovanadate could exhibit strong red emissions within the soft matrix (polyacrylamide) and remain relatively stable even when the temperature reached nearly 100 °C. After calcination process, X-ray powder diffraction patterns, SEM and DLS measurements implied that the sample was in agreement with pure tetragonal phase and the particle sizes were in the range of 100–200 nm. More importantly, YVO 4 :Eu 3+ products prepared based on hydrogels have remarkable improvement in emission intensities compared to phosphors synthesized by conventional approach. Similar results of overall quantum efficiency also support that YVO 4 :Eu 3+ assembled by PAM hydrogel (1.94%) is better than the routine way (0.91%). -- Highlights: ► YVO 4 :Eu 3+ could be formed within the soft matrix. ► The as-derived YVO 4 :Eu 3+ exhibited red emissions and remain relatively stable nearly 100 °C. ► YVO 4 :Eu 3+ prepared by hydrogels has remarkable improvement in emission intensities.

Implementation of chitosan inductively modified by γ-rays copolymerization with acrylamide in the decontamination of aqueous basic dye solution

Directory of Open Access Journals (Sweden)

R.O. Aly

2017-02-01

Full Text Available The modification induced by gamma rays for the natural polymer, chitosan, was established using the monomer acrylamide. The hydrogel obtained was characterized using Fourier transform infrared spectroscopy and the thermal properties were investigated by thermogravimetric analysis (TGA. The effect of absorbed dose (kGy and chitosan:acrylamide ratio on the gel % was studied. The impact of the polymerization variables was observed on the swelling % of the prepared hydrogel with water. The highest equilibrium degree of swelling of the prepared chitosan–AAm hydrogel, 380 g/g was predicted at 75% AAm and absorbed dose of 10 kGy for 97.7% gel. The removal of the basic blue dye (Astrazone Blue BG-200% from aqueous solutions was discussed. The adsorption capacity of basic dye on chitosan–AAm increased from 24.5 to 47.2 mg/g by increasing pH from 4.0 to 9.0. The effect of pH, absorbed dose, chitosan:AAm ratio and the concentration of the dye on the effectiveness of the adsorption process was studied.

Poly(ethylene glycol) (PEG)-lactic acid nanocarrier-based degradable hydrogels for restoring the vaginal microenvironment

Science.gov (United States)

Rajan, Sujata Sundara; Turovskiy, Yevgeniy; Singh, Yashveer; Chikindas, Michael L.; Sinko, Patrick J.

2014-01-01

Women with bacterial vaginosis (BV) display reduced vaginal acidity, which make them susceptible to associated infections such as HIV. In the current study, poly(ethylene glycol) (PEG) nanocarrier-based degradable hydrogels were developed for the controlled release of lactic acid in the vagina of BV-infected women. PEG-lactic acid (PEG-LA) nanocarriers were prepared by covalently attaching lactic acid to 8-arm PEG-SH via cleavable thioester bonds. PEG-LA nanocarriers with 4 copies of lactic acid per molecule provided controlled release of lactic acid with a maximum release of 23% and 47% bound lactic acid in phosphate buffered saline (PBS, pH 7.4) and acetate buffer (AB, pH 4.3), respectively. The PEG nanocarrier-based hydrogels were formed by cross-linking the PEG-LA nanocarriers with 4-arm PEG-NHS via degradable thioester bonds. The nanocarrier-based hydrogels formed within 20 min under ambient conditions and exhibited an elastic modulus that was 100-fold higher than the viscous modulus. The nanocarrier-based degradable hydrogels provided controlled release of lactic acid for several hours; however, a maximum release of only 10%–14% bound lactic acid was observed possibly due to steric hindrance of the polymer chains in the cross-linked hydrogel. In contrast, hydrogels with passively entrapped lactic acid showed burst release with complete release within 30 min. Lactic acid showed antimicrobial activity against the primary BV pathogen Gardnerella vaginalis with a minimum inhibitory concentration (MIC) of 3.6 mg/ml. In addition, the hydrogels with passively entrapped lactic acid showed retained antimicrobial activity with complete inhibition G. vaginalis growth within 48 h. The results of the current study collectively demonstrate the potential of PEG nanocarrier-based hydrogels for vaginal administration of lactic acid for preventing and treating BV. PMID:25223229

Polyelectrolyte Complex Nanoparticles of Poly(ethyleneimine) and Poly(acrylic acid): Preparation and Applications

OpenAIRE

Martin Müller; Bernd Keßler; Sebastian Poeschla; Bernhard Torger; Johanna Fröhlich

2011-01-01

In this contribution we outline polyelectrolyte (PEL) complex (PEC) nanoparticles, prepared by mixing solutions of the low cost PEL components poly(ethyleneimine) (PEI) and poly(acrylic acid) (PAC). It was found, that the size and internal structure of PEI/PAC particles can be regulated by process, media and structural parameters. Especially, mixing order, mixing ratio, PEL concentration, pH and molecular weight, were found to be sensible parameters to regulate the size (diameter) of spherica...

The study of polymeric hydro-gels with unique properties obtained by polymerization with gamma radiation processing

International Nuclear Information System (INIS)

Dragusin, M.

1995-01-01

This thesis presents the work carried out on polymeric hydro-gels obtained by radiation processing using 60 Co gamma rays from the irradiation facility IETI-10.000 (10 k Ci), and on the polymeric hydro-gels obtained by irradiation with the electron beams from a linear accelerator (6 MeV). The aim of the study was to determine the effect of the rate dose and total dose absorbed in the materials. There are presented the preparation methods of homo- and co-polymer hydro-gels (acrylics, namely anionic and neutral monomers (acrylamide, acrylic acid, vinyl acetate) and cationic monomers (di-methyl di-allyl ammonium chloride)) such as floculants, additives, absorbers, etc. Concerning with these we have analysed the preparation methods, the mechanical, thermal, diffusivity, and swelling properties of polymeric hydro-gels in a large variety of gels of type I or II. The technological aspects and end use were studied in connection with the characteristics of the radiation processing of these hydro-gels as a function of chemical composition rate and absorbed dose, swelling degree (low and very high hydro-soluble), mechanical and diffusional properties. (author) 33 figs., 12 tabs., 101 refs

Ionic Conductivity of Polyelectrolyte Hydrogels.

Science.gov (United States)

Lee, Chen-Jung; Wu, Haiyan; Hu, Yang; Young, Megan; Wang, Huifeng; Lynch, Dylan; Xu, Fujian; Cong, Hongbo; Cheng, Gang

2018-02-14

Polyelectrolytes have many important functions in both living organisms and man-made applications. One key property of polyelectrolytes is the ionic conductivity due to their porous networks that allow the transport of water and small molecular solutes. Among polyelectrolytes, zwitterionic polymers have attracted huge attention for applications that involve ion transport in a polyelectrolyte matrix; however, it is still unclear how the functional groups of zwitterionic polymer side chains affect their ion transport and swelling properties. In this study, zwitterionic poly(carboxybetaine acrylamide), poly(2-methacryloyloxyethyl phosphorylcholine), and poly(sulfobetaine methacrylate) hydrogels were synthesized and their ionic conductivity was studied and compared to cationic, anionic, and nonionic hydrogels. The change of the ionic conductivity of zwitterionic and nonionic hydrogels in different saline solutions was investigated in detail. Zwitterionic hydrogels showed much higher ionic conductivity than that of the widely used nonionic poly(ethylene glycol) methyl ether methacrylate hydrogel in all tested solutions. For both cationic and anionic hydrogels, the presence of mobile counterions led to high ionic conductivity in low salt solutions; however, the ionic conductivity of zwitterionic hydrogels surpassed that of cationic and ionic hydrogels in high salt solutions. Cationic and anionic hydrogels showed much higher water content than that of zwitterionic hydrogels in deionized water; however, the cationic hydrogels shrank significantly with increasing saline concentration. This work provides insight into the effects of polyelectrolyte side chains on ion transport. This can guide us in choosing better polyelectrolytes for a broad spectrum of applications, including bioelectronics, neural implants, battery, and so on.

Poly(Acrylic Acid-b-Styrene) Amphiphilic Multiblock Copolymers as Building Blocks for the Assembly of Discrete Nanoparticles

Science.gov (United States)

Greene, Anna C.; Zhu, Jiahua; Pochan, Darrin J.; Jia, Xinqiao; Kiick, Kristi L.

2011-01-01

In order to expand the utility of current polymeric micellar systems, we have developed amphiphilic multiblock copolymers containing alternating blocks of poly(acrylic acid) and poly(styrene). Heterotelechelic poly(tert-butyl acrylate-b-styrene) diblock copolymers containing an α-alkyne and an ω-azide were synthesized by atom transfer radical polymerization (ATRP), allowing control over the molecular weight while maintaining narrow polydispersity indices. The multiblock copolymers were constructed by copper-catalyzed azide-alkyne cycloaddition of azide-alkyne end functional diblock copolymers which were then characterized by 1H NMR, FT-IR and SEC. The tert-butyl moieties of the poly(tert-butyl acrylate-b-styrene) multiblock copolymers were easily removed to form the poly(acrylic acid-b-styrene) multiblock copolymer ((PAA-PS)9), which contained up to 9 diblock repeats. The amphiphilic multiblock (PAA-PS)9 (Mn = 73.3 kg/mol) was self-assembled by dissolution into tetrahydrofuran and extensive dialysis against deionized water for 4 days. The critical micelle concentration (CMC) for (PAA-PS)9 was determined by fluorescence spectroscopy using pyrene as a fluorescent probe and was found to be very low at 2 × 10-4 mg/mL. The (PAA-PS)9 multiblock was also analyzed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The hydrodynamic diameter of the particles was found to be 11 nm. Discrete spherical particles were observed by TEM with an average particle diameter of 14 nm. The poly(acrylic acid) periphery of the spherical particles should allow for future conjugation of biomolecules. PMID:21552373

Hierarchically organized architecture of potassium hydrogen phthalate and poly(acrylic acid): toward a general strategy for biomimetic crystal design.

Science.gov (United States)

Oaki, Yuya; Imai, Hiroaki

2005-12-28

A hierarchically organized architecture in multiple scales was generated from potassium hydrogen phthalate crystals and poly(acrylic acid) based on our novel biomimetic approach with an exquisite association of polymers on crystallization.

Pervaporation of alcohol-toluene mixtures through polymer blend membranes of poly(acrylic acid) and poly(vinyl alcohol)

NARCIS (Netherlands)

Park, H.C.; Park, H.; Meertens, R.M.; Meertens, R.M.; Mulder, M.H.V.; Smolders, C.A.; Smolders, C.A.

1994-01-01

Homogeneous membranes were prepared by blending poly(acrylic acid) with poly(vinyl alcohol). These blend membranes were evaluated for the selective separation of alcohols from toluene by pervaporation. The flux and selectivity of the membranes were determined both as a function of the blend

Preparation of RGO/Fe{sub 3}O{sub 4}/poly (acrylic acid) hydrogel nanocomposites with improved magnetic, thermal and electrochemical properties

Energy Technology Data Exchange (ETDEWEB)

Didehban, K.H., E-mail: Didehban95@gmail.com; Mohammadi, L.; Azimvand, J.

2017-07-01

A hydrogel nanocomposite composed of reduced graphene oxide (RGO), iron oxide (Fe{sub 3}O{sub 4}) nanoparticles, and polyacrylic acid (PAA) was prepared using radical polymerization. Different percentages of RGO, Fe{sub 3}O{sub 4}, and PAA were used to prepare the nanocomposite. Fourier transform infrared spectroscopy (FTIR) results confirmed the formation of the nanocomposite’s chemical structure. X-ray power diffraction (XRD) patterns revealed the principal peak’s 2θ value to be 77.39° with the size of the nanocomposite particles estimated at 96 nm. Results indicated that the electrochemical capacity of the nanocomposites was controlled by the weight percentage of RGO. Increases to the potential scan rate reduced porosity and surface area, thereby decreasing the electrochemical capacity of the nanocomposites. Moreover, increasing the percentage of Fe{sub 3}O{sub 4} nanoparticles in the nanocomposites improved their magnetic characteristics and thermal properties. The latter also improved when the RGO percentage increased. - Highlights: • A hydrogel nanocomposite composed of RGO/Fe{sub 3}O{sub 4}/PAA was synthesized successfully. • Increasing the percentage of iron nanoparticles improved magnetic properties. • Increasing the percentage of RGO improved thermal and electrochemical capacity. • The Fe{sub 3}O{sub 4} nanoparticles directly affected magnetic properties.

Stimuli-sensitive hydrogels: A novel ophthalmic drug delivery system

Directory of Open Access Journals (Sweden)

Singh Vinod

2010-01-01

Full Text Available Background: Stimuli-sensitive hydrogels are three-dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids on stimulation, such as pH, temperature and ionic change. Aim: To develop hydrogels that are sensitive to stimuli, i.e. pH, in the cul-de-sac of the eye for providing a prolonged effect and increased bioavailability with reduction in frequency of administration. Materials and Methods: Hydrogels were formulated by using timolol maleate as the model drug, polyacrylic acid as the gelling agents, hydroxyl ethyl cellulose as the viscolizer and sodium chloride as the isotonic agent. Stirring of ingredients in pH 4 phosphate buffer at high speed was carried out. The dynamic dialysis technique was used for drug release studies. In vivo study for reduction in intraocular pressure was carried out by using albino rabbits. Statistical Analysis: Drug release studies data were used for statistical analysis in first-order plots, Higuchi plots and Peppas exponential plots. Student t-test was performed for in vivo study. Results: Viscosity of the hydrogel increases from 3.84 cps to 9.54 cps due to change in pH 4 to pH 7.4. The slope value of the Peppas equation was found to be 0.3081, 0.3743 and 0.2964. Up to 80% of drug was released in an 8 h drug release study. Sterile hydrogels with no ocular irritation were obtained. Conclusions: Hydrogels show increase in viscosity due to change in pH. Hydrogels were therapeutically effacious, stable, non-irritant and showed Fickian diffusion. In vivo results clearly show a prolonged reduction in intraocular pressure, which was helpful for reduction in the frequency of administration.

Síntese e caracterização de hidrogéis compósitos a partir de copolímeros acrilamida-acrilato e caulim: efeito da constituição de diferentes caulins do nordeste brasileiro Synthesis and characterization of poly (acrylamide-co-acrylate and kaolin hydrogel composites: effect of the constitution of different kaolins from northeastern Brazil

Directory of Open Access Journals (Sweden)

Carlos W. de Q. Brito

2013-01-01

Full Text Available Superabsorbent hydrogels based on poly (acrylamide-co-acrylate and different kaolins, were prepared by free-radical aqueous copolymerization. FTIR and WAXS techniques were employed for characterization of a series of hydrogels, obtained by varying the percentage of clay, crosslinking and constitution of kaolin. The water absorbency at equilibrium (Weq decreased with increasing clay content and the amount of crosslinking agent. Superabsorbent hydrogel (Weq > 1084 g H2O/g gel was obtained as 10 wt% of white kaolin and 0.05 mol% of crosslinking agent were used. The hydrogel proved sensitive to pH variation and the presence of salts.

Ultrasound stimulated release of gallic acid from chitin hydrogel matrix

Energy Technology Data Exchange (ETDEWEB)

Jiang, Huixin; Kobayashi, Takaomi, E-mail: takaomi@nagaokaut.ac.jp

2017-06-01

Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24 h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0–30 W at 43 kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25 mg/cm{sup 3}) and chitin concentrations (0.1, 0.5, and 1 wt%) on the release behaviors were recorded under 43 kHz US exposure at 30 W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74 μg/mL·min was obtained from 0.54 mg/cm{sup 3} of GA-loaded hydrogel fabricated from a 0.1 wt% chitin mixture solution under 43 kHz US exposure at 30 W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. - Highlights: • Ultrasound (US) stimulated Gallic acid (GA) release from chitin hydrogel was studied. • The release efficiency of GA from chitin hydrogel increased nine times when irradiated by 43 kHz US compared with the sample without US. • Generalized 2D correlation and deconvolution study of FT-IR showed that US could promote the GA release by breaking hydrogen bonds.

Ultrasound stimulated release of gallic acid from chitin hydrogel matrix

International Nuclear Information System (INIS)

Jiang, Huixin; Kobayashi, Takaomi

2017-01-01

Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24 h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0–30 W at 43 kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25 mg/cm 3 ) and chitin concentrations (0.1, 0.5, and 1 wt%) on the release behaviors were recorded under 43 kHz US exposure at 30 W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74 μg/mL·min was obtained from 0.54 mg/cm 3 of GA-loaded hydrogel fabricated from a 0.1 wt% chitin mixture solution under 43 kHz US exposure at 30 W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. - Highlights: • Ultrasound (US) stimulated Gallic acid (GA) release from chitin hydrogel was studied. • The release efficiency of GA from chitin hydrogel increased nine times when irradiated by 43 kHz US compared with the sample without US. • Generalized 2D correlation and deconvolution study of FT-IR showed that US could promote the GA release by breaking hydrogen bonds.

Effect of amino acids and frequency of reuse frying oils at different temperature on acrylamide formation in palm olein and soy bean oils via modeling system.

Science.gov (United States)

Daniali, G; Jinap, S; Sanny, M; Tan, C P

2018-04-15

This work investigated the underlying formation of acrylamide from amino acids in frying oils during high temperatures and at different times via modeling systems. Eighteen amino acids were used in order to determine which one was more effective on acrylamide production. Significantly the highest amount of acrylamide was produced from asparagine (5987.5µg/kg) and the lowest from phenylalanine (9.25µg/kg). A constant amount of asparagine and glutamine in palm olein and soy bean oils was heated up in modelling system at different temperatures (160, 180 and 200°C) and times (1.5, 3, 4.5, 6, 7.5min). The highest amount of acrylamide was found at 200°C for 7.5min (9317 and 8511µg/kg) and lowest at 160°C for 1.5min (156 and 254µg/kg) in both frying oils and both amino acids. Direct correlations have been found between time (R 2 =0.884), temperature (R 2 =0.951) and amount of acrylamide formation, both at p<0.05. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation of poly(acrylamide-co-acrylic acid)-grafted gum and its flocculation and biodegradation studies.

Science.gov (United States)

Mittal, H; Mishra, Shivani B; Mishra, A K; Kaith, B S; Jindal, R; Kalia, S

2013-10-15

Biodegradation studies of Gum ghatti (Gg) and acrylamide-co-acrylic acid based flocculants [Gg-cl-poly(AAm-co-AA)] have been reported using the soil composting method. Gg-cl-poly(AAm-co-AA) was found to degrade 89.76% within 60 days. The progress of biodegradation at each stage was monitored through FT-IR and SEM. Polymer was synthesized under pressure using potassium persulphate-ascorbic acid as a redox initiator and N,N'-methylene-bis-acrylamide as a crosslinker. Synthesized polymer was found to show pH, temperature and ionic strength of the cations dependent swelling behavior. Gg-cl-poly(AAm-co-AA) was utilized for the selective absorption of saline from different petroleum fraction-saline emulsions. The flocculation efficiency of the polymer was studied as a function of polymer dose, temperature and pH of the solution. Gg-cl-poly(AAm-co-AA) showed maximum flocculation efficiency with 20 mol L(-1) polymer dose in acidic medium at 50 °C. Copyright © 2013. Published by Elsevier Ltd.

Interaction of Fe(II) with Polyacrylic Acid as a Simplification of Humic Acid: Comparison of Ion Exchange and Solvent Extraction Methods

International Nuclear Information System (INIS)

Budi Setiawan

2007-01-01

To estimate the safety assessment around the disposal facility, the interaction behavior of radionuclides/metal ions into organic material (such as humic acids) exist in natural water becomes an important study. To avoid the effect of heterogeneous composition of humic acid, polyacrylic acids (abbrev. APA) was used as are representative of homogeneous polymeric weak acid. The experiments have been carried out by solvent extraction and ion exchange methods to find out the suitable method for the study of complex formation of Fe(II) with humic acid(AH) and APA. The solvent extraction experiment has been done by using diphenylthiocarbazone (dithizone) in CCl 4 and C Fe(II) were 10 -8 M to 10 -5 M, pH around 5 and I=0.1M NaCI. In ionic exchange experiment, C Fe(II) were 10 -8 to 10 -4 M, pH from 4.8 to 5.5 in I=0.1M NaCl. The apparent complex formation constant is defined as β α = [ML]/([M][R]), where [M] and [ML] are concentration of free and bound of Fe(II) and [R] is the concentration of dissociated carboxylic group in macromolecules of PAA. The results shown that, for solvent extraction experiments, variable concentration of Fe(II) had no appreciable influence on the distribution ratio of Fe(II)-polyacrylate at the tracer concentration with the log D to be 1.32 ± 0.03 (pcH 5.25). At macro concentration, the distribution ratio of Fe(II) becomes smaller due to oxidation and obtained log D value to be 1.04 ± 0.07 (pcH 5.34). An interest kind was observed at higher PAA concentration, the distribution ratio curve becomes higher presumably due to the problem on redox sensitive characteristic of Fe(II) and/or coagulation of Fe(II)-polyacrylate at the interface of aqueous-organic phases. In case of ionic exchange method, the plot of I/Kd versus [R] gives a straight line result indicating this method is appropriate and more superior compare than solvent extraction method to determine the complex formation constant. (author)

Magnetic hyperthermia studies on water-soluble polyacrylic acid-coated cobalt ferrite nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Krishna Surendra, M. [Indian Institute of Technology Madras, Department of Physics, Nano Functional Materials Technology Centre, Materials Research Centre (India); Annapoorani, S. [Anna University of Technology, Department of Nanotechnology (India); Ansar, Ereath Beeran; Harikrishna Varma, P. R. [Sree Chitra Tirunal Institute for Medical Sciences and Technology, Bioceramics Laboratory (India); Ramachandra Rao, M. S., E-mail: msrrao@iitm.ac.in [Indian Institute of Technology Madras, Department of Physics, Nano Functional Materials Technology Centre, Materials Research Centre (India)

2014-12-15

We report on synthesis and hyperthermia studies in the water-soluble ferrofluid made of polyacrylic acid-coated cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles with different particle sizes. Magnetic nanoparticles were synthesized using co-precipitation method and particle size was varied as 6, 10, and 14 nm by varying the precursor to surfactant concentration. PAA surfactant bonding and surfactant thickness were studied by FTIR and thermogravimetric analysis. At room temperature, nanoparticles show superparamagnetism and saturation magnetization was found to vary from 33 to 44 emu/g with increase in the particle size from 6 to 14 nm, and this increase was attributed to the presence of a magnetic inert layer of 4 Å thick. Effect of particle size, concentration, and alternating magnetic field strength at 275 kHz on specific absorption rate were studied by preparing ferrofluids in deionized water at different concentrations. Ferrofluids at a concentration of 1.25 g/L, with 10 min of AMF exposure of strength ∼15.7 kA/m show stable temperatures ∼48, 58, and 68 °C with increase in the particle sizes 6, 10, and 14 nm. A maximum specific absorption rate of 251 W/g for ferrofluid with a particle size of 10 nm at 1.25 g/L, 15.7 kA/m, and 275 kHz was observed. Viability of L929 fibroblasts is measured by MTT assay cytotoxicity studies using the polyacrylic acid-coated CoFe{sub 2}O{sub 4} nanoparticles.

Antioxidant effect of vitamin E and 5-aminosalicylic acid on acrylamide induced kidney injury in rats

Directory of Open Access Journals (Sweden)

Nisreen A. Rajeh

2017-02-01

Full Text Available exposure of acrylamide and to study the protective effect of 5-Aminosalicylic acid (5-ASA and Vitamin E (vit-Eon Acrylamide (ACR induced renal toxicity. Methods: This study was conducted at King Fahad Medical Research Centre, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia, between August and November 2015. A total of 49 adult Wistar rats (250 ± 20g aged 60 days were kept in a controlled environment and used in the present study. The rats were divided into 7 groups (control, ACR alone, ACR+5-ASA, ACR+vit-E, ACR+ASA+vit-E, vit-E alone, and ASA alone. After 5 days of ACR oral gavage treatment, the rats were observed for 24 hours then killed. Histopathology for the kidney and lactate dehydrogenase assay were carried out. Results: Acrylamide produced significant pathological changes in the kidney with acute tubular necrosis in the distal tubules that could be reversed by concomitant injection of rat with 5-ASA. Together with vitamin E, 5-ASA, showed maximum renal protection. No statistically significant difference was observed in either body weights or lactate dehydrogenase activity of ACR treated rats. Conclusion: Acrylamide exposure leads to adverse clinical pathologies of renal tubules, which were reversed by a concomitant treatment with 5-ASA and vitamin-E

Acrylamide formation in plantain (Musa paradisiaca) chips influenced by different ripening stages: A correlation study with respect to reducing sugars, amino acids and phenolic content.

Science.gov (United States)

Shamla, L; Nisha, P

2017-05-01

The effect of ripening on the formation of acrylamide in deep fried plantain chips made from Nendran variety (Musa paradisiaca) was investigated. The precursors of acrylamide formation, reducing sugars (glucose and fructose) and ten major amino acids, were quantified during different stages of ripening using HPLC and correlated with acrylamide formation. The total phenolic content and total flavonoid content were also estimated and correlated with acrylamide formation. Both glucose and fructose increased during ripening and demonstrated a positive correlation on formation of acrylamide (correlation coefficient of r=0.95 and 0.94 respectively (p0.05). The decreased levels of phenolic content during ripening of plantain were negatively correlated with acrylamide formation in the deep fried chips prepared. Thus the selection of proper ripening stage renders reduced formation of acrylamide in plantain chips to a reasonable extend. Copyright © 2016 Elsevier Ltd. All rights reserved.

Adsorption of crude oil from aqueous solution by hydrogel of chitosan based polyacrylamide prepared by radiation induced graft polymerization

Energy Technology Data Exchange (ETDEWEB)

Sokker, H.H., E-mail: hesham_sokkre@yahoo.com [Jazan University, Faculty of Science (Saudi Arabia); National Center for Radiation Research and Technology, Polymer Chemistry Department, P.O. Box 29, Cairo (Egypt); El-Sawy, Naeem M. [National Center for Radiation Research and Technology, Polymer Chemistry Department, P.O. Box 29, Cairo (Egypt); Hassan, M.A. [Scib Company of Paints, Cairo (Egypt); El-Anadouli, Bahgat E. [Chemistry Department, Faculty of Science, Cairo University, Giza 12613 (Egypt)

2011-06-15

The adsorption of crude oil (initial concentration 0.5-30 g/L) from aqueous solution using hydrogel of chitosan based polyacrylamide (PAM) prepared by radiation induced graft polymerization has been investigated. The prepared hydrogel was characterized by FTIR and SEM micrographs. The experiments were carried out as a function of different initial concentrations of oil residue, acrylamide concentration, contact time and pH to determine the optimum condition for the adsorption of residue oil from aqueous solution and sea water. The results obtained showed that the hydrogel prepared at concentration of 40% acrylamide (AAm) and at a radiation dose of 5 kGy has high removal efficiency of crude oil 2.3 g/g at pH 3. Equilibrium studies have been carried out to determine the capacity of the hydrogel for adsorption of crude oil, Langmuir and Freundlich adsorption models were applied to describe the experimental isotherms and isotherms constants. Equilibrium data were found to fit very well with both Freundlich and Langmuir models. Also the adsorption of oil onto the hydrogel behaves as a pseudo-second-order kinetic models rather than the pseudo-first-order kinetic model.

Electrochemical supercapacitor electrode material based on polyacrylic acid/polypyrrole/silver composite

International Nuclear Information System (INIS)

Patil, Dipali S.; Pawar, Sachin A.; Devan, Rupesh S.; Gang, Myeng Gil; Ma, Yuon-Ron; Kim, Jin Hyeok; Patil, Pramod S.

2013-01-01

Highlights: • Polyacrylic acid/polypyrrole/silver composite prepared by chemical polymerization method. • The presence of Ag nanoparticles on PPY spherical granules provides the least resistance path to electron. • The specific capacitance about 145 F g −1 and 226 F g −1 observed for PPY/PAA and PPY/PAA/Ag samples, respectively. • The higher specific energy 7.18 Wh kg −1 and 17.45 Wh kg −1 observed for PPY/PAA and PPY/PAA/Ag respectively at current density of 0.5 mA cm −2 . -- Abstract: In the present work, we have synthesized polypyrrole (PPY)/polyacrylic acid (PAA)/silver (Ag) composite electrodes by chemical polymerization via a simple and cost effective dip coating technique for supercapacitor application. Fourier transform-infrared, Fourier transform-Raman, X-ray photoelectron and energy dispersive X-ray spectroscopy techniques are used for the phase identification. Surface morphology of the films is examined by field emission scanning electron microscopy, which revealed granular structure for PPY, spherical interlaced granules for PPY/PAA and granules with bright spots of Ag nanoparticles for the PPY/PAA/Ag composites. The supercapacitive behavior of the electrodes is tested in three electrode system with 0.1 M H 2 SO 4 electrolyte by using cyclic voltammetery and charge discharge test. The highest specific capacitance 226 F g −1 at 10 mV s −1 and energy density of 17.45 Wh kg −1 at 0.5 mA cm −2 is obtained for the PPY/PAA/Ag composite electrodes. Present work demonstrates an easy way of improving specific capacitance of the polymer electrodes. Thus the work will open a new avenue for designing low cost high performance devices for better supercapacitors

UV-radiation curing of simultaneous interpenetrating polymer network hydrogels for enhanced heavy metal ion removal

International Nuclear Information System (INIS)

Wang, Jingjing; Liu, Fang

2012-01-01

Highlights: ► Simultaneous IPN hydrogels were prepared by hybrid photopolymerization of AM and DVE-3. ► The synergistic complexation was found in the adsorption studies. ► The simultaneous IPN hydrogels could be used as fast-responsive and renewable sorbent materials. - Abstract: Simultaneous interpenetrating polymer network (IPN) hydrogels have been prepared by UV-initiated polymerization of a mixture of acrylamide (AM) and triethylene glycol divinyl ether (DVE-3). The consumption of each monomer upon UV-irradiation was monitored in situ by real-time infrared (RTIR) spectroscopy. The acrylamide monomer AM was shown to polymerize faster and more extensively than the vinyl ether monomer DVE-3, which was further consumed upon storage of the sample in the dark, due to the living character of the cationic polymerization. The IPN hydrogels were used to remove heavy metal ions from aqueous solution under the non-competitive condition. The effects of pH values of the feed solution and the DVE-3 content in the formulation on the adsorption capacity were investigated. The results indicated that the adsorption capacity of the IPN hydrogels increased with the pH values and DVE-3 content in the formulation. Furthermore, the synergistic complexation of metal ions with two polymer networks in the IPN was found in the adsorption studies. Adsorption kinetics and regeneration studies suggested that the IPN hydrogels could be used as fast-responsive and renewable sorbent materials in heavy metal removing processes.

Preparation and characterization of poly(acrylic acid)-hydroxyethyl cellulose graft copolymer.

Science.gov (United States)

Abdel-Halim, E S

2012-10-01

Poly(acrylic acid) hydroxyethyl cellulose [poly(AA)-HEC] graft copolymer was prepared by polymerizing acrylic acid (AA) with hydroxyethyl cellulose (HEC) using potassium bromate/thiourea dioxide (KBrO(3)/TUD) as redox initiation system. The polymerization reaction was carried out under a variety of conditions including concentrations of AA, KBrO(3) and TUD, material to liquor ratio and polymerization temperature. The polymerization reaction was monitored by withdrawing samples from the reaction medium and measuring the total conversion. The rheological properties of the poly(AA)-HEC graft copolymer were investigated. The total conversion and rheological properties of the graft copolymer depended on the ratio of KBrO(3) to TUD and on acrylic acid concentration as well as temperature and material to liquor ratio. Optimum conditions of the graft copolymer preparation were 30 mmol KBrO(3) and 30 mmol TUD/100g HEC, 100% AA (based on weight of HEC), duration 2h at temperature 50 °C using a material to liquor ratio of 1:10. Copyright © 2012. Published by Elsevier Ltd.

Radiation Synthesis of Poly(N-Vinyl Pyrrolidone) Nanogels and Nanoscale Grafting of Poly(Acrylic Acid) from Cellulose

Energy Technology Data Exchange (ETDEWEB)

Guven, Olgun; Isik, Semiha Duygu; Barsbay, Murat [Hacettepe University, Department of Chemistry, 06800 Ankara (Turkey)

2010-07-01

Ionizing radiation has long been known to be a very useful tool for the preparation of nanogels. Although preparation is straightforward, the control of the sizes of nanogels has been a challenging issue. This report shows the results of our work on using radiation for the synthesis of PVP nanogels in the range of 40-200nm by making use of the principles of solution thermodynamics of aqueous polymer solutions. Nanoscale grafting of responsive polymers however has been of scientific and industrial importance due to fine control of the molecular weight and molecular weight distribution of grafted polymers. The second part of this report deals with the grafting of poly(acrylic acid) onto the surface of cellulose, thus imparting pH response to the substrate. The use of radiation as a constant source of radical generation and Reversible-Addition-Fragmentation-Chain transfer agents for the control of free radical polymerization provided a full control over the molecular weight and distribution of poly(acrylic acid) grafts on cellulose. (author)

Radiation Synthesis of Poly(N-Vinyl Pyrrolidone) Nanogels and Nanoscale Grafting of Poly(Acrylic Acid) from Cellulose

International Nuclear Information System (INIS)

Guven, Olgun; Isik, Semiha Duygu; Barsbay, Murat

2010-01-01

Ionizing radiation has long been known to be a very useful tool for the preparation of nanogels. Although preparation is straightforward, the control of the sizes of nanogels has been a challenging issue. This report shows the results of our work on using radiation for the synthesis of PVP nanogels in the range of 40-200nm by making use of the principles of solution thermodynamics of aqueous polymer solutions. Nanoscale grafting of responsive polymers however has been of scientific and industrial importance due to fine control of the molecular weight and molecular weight distribution of grafted polymers. The second part of this report deals with the grafting of poly(acrylic acid) onto the surface of cellulose, thus imparting pH response to the substrate. The use of radiation as a constant source of radical generation and Reversible-Addition-Fragmentation-Chain transfer agents for the control of free radical polymerization provided a full control over the molecular weight and distribution of poly(acrylic acid) grafts on cellulose. (author)

Acrylamide reduction under different pre-treatments in French fries

DEFF Research Database (Denmark)

Pedreschi, Franco; Kaack, Karl; Granby, Kit

2007-01-01

of similar to 40 g water/100 g (total basis). Prior to frying, potato strips were treated in one of the following ways: (i) immersed in distilled water for 0 min (control), 60 min and 120 min; (ii) immersed in a citric acid solution of 10 g/L for an hour; (iii) immersed in a sodium pyrophosphate solution...... strips before frying. Immersed strips in water for 120 min showed a reduction of acrylamide formation of 33%, 21% and 27% at 150, 170 and 190 degrees C, respectively, when they were compared against the control. Potato strips blanched at 50 degrees C for 80 min had the lowest acrylamide content when...... compared against strips blanched at different conditions and fried at the same temperature (135, 327 and 564 mu m acrylamide/kg for 150, 170 and 190 degrees C, respectively). Potato strip immersion in citric acid solution of 10 g/L reduced much more the acrylamide formation after frying than the strip...

Modified Polyacrylic Acid-Zinc Composites: Synthesis, Characterization and Biological Activity

Directory of Open Access Journals (Sweden)

Mohammed Rafi Shaik

2016-02-01

Full Text Available Polyacrylic acid (PAA is an important industrial chemical, which has been extensively applied in various fields, including for several biomedical purposes. In this study, we report the synthesis and modification of this polymer with various phenol imides, such as succinimide, phthalimide and 1,8-naphthalimide. The as-synthesized derivatives were used to prepare polymer metal composites by the reaction with Zn+2. These composites were characterized by using various techniques, including NMR, FT-IR, TGA, SEM and DSC. The as-prepared PAA-based composites were further evaluated for their anti-microbial properties against various pathogens, which include both Gram-positive and Gram-negative bacteria and different fungal strains. The synthesized composites have displayed considerable biocidal properties, ranging from mild to moderate activities against different strains tested.

Energy Recovery from Solutions with Different Salinities Based on Swelling and Shrinking of Hydrogels

KAUST Repository

Zhu, Xiuping

2014-06-17

Several technologies, including pressure-retarded osmosis (PRO), reverse electrodialysis (RED), and capacitive mixing (CapMix), are being developed to recover energy from salinity gradients. Here, we present a new approach to capture salinity gradient energy based on the expansion and contraction properties of poly(acrylic acid) hydrogels. These materials swell in fresh water and shrink in salt water, and thus the expansion can be used to capture energy through mechanical processes. In tests with 0.36 g of hydrogel particles 300 to 600 μm in diameter, 124 mJ of energy was recovered in 1 h (salinity ratio of 100, external load of 210 g, water flow rate of 1 mL/min). Although these energy recovery rates were relatively lower than those typically obtained using PRO, RED, or CapMix, the costs of hydrogels are much lower than those of membranes used in PRO and RED. In addition, fouling might be more easily controlled as the particles can be easily removed from the reactor for cleaning. Further development of the technology and testing of a wider range of conditions should lead to improved energy recoveries and performance. © 2014 American Chemical Society.

Energy Recovery from Solutions with Different Salinities Based on Swelling and Shrinking of Hydrogels

KAUST Repository

Zhu, Xiuping; Yang, Wulin; Hatzell, Marta C.; Logan, Bruce E.

2014-01-01

Several technologies, including pressure-retarded osmosis (PRO), reverse electrodialysis (RED), and capacitive mixing (CapMix), are being developed to recover energy from salinity gradients. Here, we present a new approach to capture salinity gradient energy based on the expansion and contraction properties of poly(acrylic acid) hydrogels. These materials swell in fresh water and shrink in salt water, and thus the expansion can be used to capture energy through mechanical processes. In tests with 0.36 g of hydrogel particles 300 to 600 μm in diameter, 124 mJ of energy was recovered in 1 h (salinity ratio of 100, external load of 210 g, water flow rate of 1 mL/min). Although these energy recovery rates were relatively lower than those typically obtained using PRO, RED, or CapMix, the costs of hydrogels are much lower than those of membranes used in PRO and RED. In addition, fouling might be more easily controlled as the particles can be easily removed from the reactor for cleaning. Further development of the technology and testing of a wider range of conditions should lead to improved energy recoveries and performance. © 2014 American Chemical Society.

Manganese oxide electrochemical capacitor with potassium poly(acrylate) hydrogel electrolyte

Science.gov (United States)

Lee, Kuang-Tsin; Wu, Nae-Lih

An aqueous gel electrolyte has for the first time been successfully applied to the MnO 2· nH 2O-based pseudocapacitive electrochemical capacitors (ECs). The gel electrolyte is made of potassium poly(acrylate) (PAAK) polymer and aqueous solution of KCl. With the selected composition, PAAK:KCl:H 2O = 9.0%:6.7%:84.3% by weight, the gel shows no fluidity, possessing an ionic conductivity in the order of 10 -1 S cm -1. The gel electrolyte has been found to give substantially higher specific capacitances than those in the liquid electrolyte with the same salt (KCl) composition (1 M) and high power capability (>10 kW/kg).

Manganese oxide electrochemical capacitor with potassium poly(acrylate) hydrogel electrolyte

Energy Technology Data Exchange (ETDEWEB)

Lee, Kuang-Tsin; Wu, Nae-Lih [Department of Chemical Engineering, National Taiwan University, Taipei 106 (China)

2008-04-15

An aqueous gel electrolyte has for the first time been successfully applied to the MnO{sub 2}.nH{sub 2}O-based pseudocapacitive electrochemical capacitors (ECs). The gel electrolyte is made of potassium poly(acrylate) (PAAK) polymer and aqueous solution of KCl. With the selected composition, PAAK:KCl:H{sub 2}O = 9.0%:6.7%:84.3% by weight, the gel shows no fluidity, possessing an ionic conductivity in the order of 10{sup -1} S cm{sup -1}. The gel electrolyte has been found to give substantially higher specific capacitances than those in the liquid electrolyte with the same salt (KCl) composition (1 M) and high power capability (>10 kW/kg). (author)

Effectiveness of methods for reducing acrylamide in bakery products.

Science.gov (United States)

Sadd, Peter A; Hamlet, Colin G; Liang, Li

2008-08-13

Pilot-scale bread, biscuit, and cracker doughs have been baked to assess how well recipe changes could reduce acrylamide in commercial bakery products. Removing ammonium-based raising agents was beneficial in biscuits. In doughs, long yeast fermentations were an effective way of reducing asparagine levels and hence acrylamide. At moderate fermentation times fructose levels increased, but the yeast later absorbed this, so the net effect on acrylamide was beneficial. Metal ions such as calcium reduced acrylamide when added as the carbonate or chloride. Hence, the fortification of flour with calcium carbonate, over and above its natural mineral content, has an additional benefit. However, some other possible methods of adding calcium to bakery doughs, for example, via the permitted preservative calcium propionate, were not beneficial. Amino acid addition to doughs gave modest reductions in acrylamide. Lowering the dough pH reduced acrylamide, but at the expense of higher levels of other process contaminants such as 3-monochloropropane-1,2-diol (3-MCPD).

Control of the rheological properties of clay nanosheet hydrogels with a guanidinium-attached calix[4]arene binder.

Science.gov (United States)

Lee, Ji Ha; Kim, Chaelin; Jung, Jong Hwa

2015-10-21

A 1,3-alternate calix[4]arene derivative 1 possessing four guanidinium moieties was synthesized as a molecular binder. The clay nanosheet (CNS) hydrogels were prepared upon addition of 1 and sodium polyacrylate (ASSP), and their mechanical properties were measured by rheometry. CNS hydrogels prepared by combining calix[4]arene 1 with dispersed CNSs surrounded by ASSPs showed an enhancement of mechanical properties such as viscosity and elasticity.

Antioxidant effect of vitamin E and 5-aminosalicylic acid on acrylamide induced kidney injury in rats

Science.gov (United States)

Rajeh, Nisreen A.; Al-Dhaheri, Najlaa M.

2017-01-01

Objectives: To explore renal toxicity caused by sub-acute exposure of acrylamide and to study the protective effect of 5-Aminosalicylic acid (5-ASA) and Vitamin E (vit-E)on Acrylamide (ACR) induced renal toxicity. Methods: This study was conducted at King Fahad Medical Research Centre, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia, between August and November 2015. A total of 49 adult Wistar rats (250 ± 20g) aged 60 days were kept in a controlled environment and used in the present study. The rats were divided into 7 groups (control, ACR alone, ACR+5-ASA, ACR+vit-E, ACR+ASA+vit-E, vit-E alone, and ASA alone). After 5 days of ACR oral gavage treatment, the rats were observed for 24 hours then killed. Histopathology for the kidney and lactate dehydrogenase assay were carried out. Results: Acrylamide produced significant pathological changes in the kidney with acute tubular necrosis in the distal tubules that could be reversed by concomitant injection of rat with 5-ASA. Together with vitamin E, 5-ASA, showed maximum renal protection. No statistically significant difference was observed in either body weights or lactate dehydrogenase activity of ACR treated rats. Conclusion: Acrylamide exposure leads to adverse clinical pathologies of renal tubules, which were reversed by a concomitant treatment with 5-ASA and vitamin-E PMID:28133684

Hydrogels of polyvinylpyrrolidone (PVP) and poly(acrylic acid) (PAA) synthesized by radiation-induced crosslinking of homopolymers

Science.gov (United States)

Kadłubowski, Sławomir; Henke, Artur; Ulański, Piotr; Rosiak, Janusz M.

2010-03-01

pH-sensitive PVP-PAA hydrogels have been prepared by electron-beam-induced irradiation at pH close to pKa of carboxylic groups. Protonation of these groups promoted the formation of hydrogen bonds between the PAA and PVP segments within the crosslinked structure and caused interpolymer complex formation. To demonstrate possible future application of such gels, we tested them as simple chemical detectors. When loaded with glucose oxidase, the PAA-PVP gel's turbidity and shrinkage was triggered by the presence of glucose due to a drop in pH caused by the enzymatic reaction.

Synthesis of luminescent YVO{sub 4}:Eu{sup 3+} submicrometer crystals through hydrogels as directing agents

Energy Technology Data Exchange (ETDEWEB)

Li, Yan; Zheng, Yuhui [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Ministry of Education (MOE) Key Laboratory of Theoretical and Environmental Chemistry, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Zhang, Cheng Cheng [Departments of Physiology and Developmental Biology, University of Texas Southwestern MedicalCenter, Dallas (United States)

2012-08-15

The innovative hydrogel template (polyacrylamide or polyacrylic acid) directed synthesis of YVO{sub 4}:Eu{sup 3+} phosphor in a controlled manner was thoroughly studied. Photoluminescence spectra show the europium(III)-doped yttrium orthovanadate could exhibit strong red emissions within the soft matrix (polyacrylamide) and remain relatively stable even when the temperature reached nearly 100 Degree-Sign C. After calcination process, X-ray powder diffraction patterns, SEM and DLS measurements implied that the sample was in agreement with pure tetragonal phase and the particle sizes were in the range of 100-200 nm. More importantly, YVO{sub 4}:Eu{sup 3+} products prepared based on hydrogels have remarkable improvement in emission intensities compared to phosphors synthesized by conventional approach. Similar results of overall quantum efficiency also support that YVO{sub 4}:Eu{sup 3+} assembled by PAM hydrogel (1.94%) is better than the routine way (0.91%). -- Highlights: Black-Right-Pointing-Pointer YVO{sub 4}:Eu{sup 3+} could be formed within the soft matrix. Black-Right-Pointing-Pointer The as-derived YVO{sub 4}:Eu{sup 3+} exhibited red emissions and remain relatively stable nearly 100 Degree-Sign C. Black-Right-Pointing-Pointer YVO{sub 4}:Eu{sup 3+} prepared by hydrogels has remarkable improvement in emission intensities.

A study on synthesis and properties of Ag nanoparticles immobilized polyacrylamide hydrogel composites

International Nuclear Information System (INIS)

Saravanan, P.; Padmanabha Raju, M.; Alam, Sarfaraz

2007-01-01

Synthesis of Ag nanoparticles containing polyacrylamide (PAm) hydrogel composites was performed by free-radical cross-linking polymerization of acrylamide monomer in an aqueous medium containing Ag + ions. The Ag nanoparticle/PAm composites exhibit faint yellow colour and are found to stable under ambient conditions, without undergoing oxidation. TEM micrographs reveal the presence of nearly spherical and well-separated Ag nanoparticles with diameters in the range of 4-7 nm. UV-vis studies apparently show the characteristic surface plasmon band at ∼415 nm, for the existence of Ag nanoparticles within the hydrogel matrix. The effect of varying Ag + ion concentration within the PAm hydrogels on the amount of formation of Ag nanoparticles, as well as on the bulk properties of hydrogel nanocomposites such as equilibrium swelling, optical and electrical properties are studied. The Ag/PAm hydrogel nanocomposites have higher swelling ratio and lower electron transfer resistance than its corresponding conventional hydrogel

Gamma ray-induced synthesis of hyaluronic acid/chondroitin sulfate-based hydrogels for biomedical applications

Science.gov (United States)

Zhao, Linlin; Gwon, Hui-Jeong; Lim, Youn-Mook; Nho, Young-Chang; Kim, So Yeon

2015-01-01

Hyaluronic acid (HA)/chondroitin sulfate (CS)/poly(acrylic acid) (PAAc) hydrogel systems were synthesized by gamma-ray irradiation without the use of additional initiators or crosslinking agents to achieve a biocompatible hydrogel system for skin tissue engineering. HA and CS derivatives with polymerizable residues were synthesized. Then, the hydrogels composed of glycosaminoglycans, HA, CS, and a synthetic ionic polymer, PAAc, were prepared using gamma-ray irradiation through simultaneous free radical copolymerization and crosslinking. The physicochemical properties of the HA/CS/PAAc hydrogels having various compositions were investigated to evaluate their feasibility as artificial skin substitutes. The gel fractions of the HA/CS/PAAc hydrogels increased in absorbed doses up to 15 kGy, and they exhibited 91-93% gel fractions under 15 kGy radiation. All of the HA/CS/PAAc hydrogels exhibited relatively high water contents of over 90% and reached an equilibrium swelling state within 24 h. The enzymatic degradation kinetics of the HA/CS/PAAc hydrogels depended on both the concentration of the hyaluronidase solution and the ratio of HA/CS/PAAc. The in vitro drug release profiles of the HA/CS/PAAc hydrogels were significantly influenced by the interaction between the ionic groups in the hydrogels and the ionic drug molecules as well as the swelling of the hydrogels. From the cytotoxicity results of human keratinocyte (HaCaT) cells cultured with extracts of the HA/CS/PAAc hydrogels, all of the HA/CS/PAAc hydrogel samples tested showed relatively high cell viabilities of more than 82%, and did not induce any significant adverse effects on cell viability.

Acrylamide graft over silicone rubber tubes by simultaneous irradiation in 60 Co source

International Nuclear Information System (INIS)

Julio, C.A.; Higa, O.Z.

1992-01-01

The synthesis of a hydrogel having silicone rubber tubes as support was carried out through the radiation grafting technique. The best conditions for the grafting development were determined in relation to the monomer and inhibitor concentration, dose rate and irradiation dose. The addition of cupric ions in the process inhibited the acrylamide homo polymerization and enhanced the grafting yield. The water content in the grafted tubes characterized the hydrophilic property of the material. (author)

Radiation Synthesis and Application of Absorbent Hydrogels to Enhance the Quality of Basadiesel

International Nuclear Information System (INIS)

Nguyen Duy Hang; Pham Thi Le Ha; Tran Thi Thuy; Le Hai; Nguyen Tan Man; Le Huu Tu; Nguyen Trong Hoanh Phong; Tran Thi Tam; Tran Thu Hong; Pham Thi Sam; Nguyen Tuong Li Lan

2013-01-01

Studying on the using ability of radiation synthesis hydrogels to enhance the quality of the biodiesel produced from Basa fish oil was implemented. Radiation synthesis of absorbent hydrogels and their application to removal of contaminants from biodiesel produced from fish oil were the major problems. The preparation of the super absorbent hydrogel obtained by radiation induced cross linking of polyacrylamide and polyacrylic was investigated and its application in removal of water, catalyst from the basadiesel emulsion is reported. The hydrogels were characterized in terms of gel content, swelling, character of water and mineral catalyst removal were studied. The effect of temperature, NaOH and KOH content of solution on the swelling degree of hydrogels was also determined. The results showed that the gel fraction of PAAm/PAAc hydrogel with PAAm/AAc (1/4) ratio and dose of 20 kGy was used to synthesized the Gel of A-311. Studies also made on the application of Gel A-311 during the refining process in Basadiesel industry. (author)

Biodegradable hyaluronic acid hydrogels to control release of dexamethasone through aqueous Diels–Alder chemistry for adipose tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Fan, Ming; Ma, Ye; Zhang, Ziwei; Mao, Jiahui [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing (China); Tan, Huaping, E-mail: hptan@njust.edu.cn [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing (China); Hu, Xiaohong [School of Material Engineering, Jinling Institute of Technology, Nanjing (China)

2015-11-01

A robust synthetic strategy of biopolymer-based hydrogels has been developed where hyaluronic acid derivatives reacted through aqueous Diels–Alder chemistry without the involvement of chemical catalysts, allowing for control and sustain release of dexamethasone. To conjugate the hydrogel, furan and maleimide functionalized hyaluronic acid were synthesized, respectively, as well as furan functionalized dexamethasone, for the covalent immobilization. Chemical structure, gelation time, morphologies, swelling kinetics, weight loss, compressive modulus and dexamethasone release of the hydrogel system in PBS at 37 °C were studied. The results demonstrated that the aqueous Diels–Alder chemistry provides an extremely selective reaction and proceeds with high efficiency for hydrogel conjugation and covalent immobilization of dexamethasone. Cell culture results showed that the dexamethasone immobilized hydrogel was noncytotoxic and preserved proliferation of entrapped human adipose-derived stem cells. This synthetic approach uniquely allows for the direct fabrication of biologically functionalized gel scaffolds with ideal structures for adipose tissue engineering, which provides a competitive alternative to conventional conjugation techniques such as copper mediated click chemistry. - Highlights: • A biodegradable hyaluronic acid hydrogel was crosslinked via aqueous Diels–Alder chemistry. • Dexamethasone was covalently immobilized into the hyaluronic acid hydrogel via aqueous Diels–Alder chemistry. • Dexamethasone could be released from the Diels–Alder hyaluronic acid hydrogel in a controlled fashion.

Biodegradable hyaluronic acid hydrogels to control release of dexamethasone through aqueous Diels–Alder chemistry for adipose tissue engineering

International Nuclear Information System (INIS)

Fan, Ming; Ma, Ye; Zhang, Ziwei; Mao, Jiahui; Tan, Huaping; Hu, Xiaohong

2015-01-01

A robust synthetic strategy of biopolymer-based hydrogels has been developed where hyaluronic acid derivatives reacted through aqueous Diels–Alder chemistry without the involvement of chemical catalysts, allowing for control and sustain release of dexamethasone. To conjugate the hydrogel, furan and maleimide functionalized hyaluronic acid were synthesized, respectively, as well as furan functionalized dexamethasone, for the covalent immobilization. Chemical structure, gelation time, morphologies, swelling kinetics, weight loss, compressive modulus and dexamethasone release of the hydrogel system in PBS at 37 °C were studied. The results demonstrated that the aqueous Diels–Alder chemistry provides an extremely selective reaction and proceeds with high efficiency for hydrogel conjugation and covalent immobilization of dexamethasone. Cell culture results showed that the dexamethasone immobilized hydrogel was noncytotoxic and preserved proliferation of entrapped human adipose-derived stem cells. This synthetic approach uniquely allows for the direct fabrication of biologically functionalized gel scaffolds with ideal structures for adipose tissue engineering, which provides a competitive alternative to conventional conjugation techniques such as copper mediated click chemistry. - Highlights: • A biodegradable hyaluronic acid hydrogel was crosslinked via aqueous Diels–Alder chemistry. • Dexamethasone was covalently immobilized into the hyaluronic acid hydrogel via aqueous Diels–Alder chemistry. • Dexamethasone could be released from the Diels–Alder hyaluronic acid hydrogel in a controlled fashion

A photo-crosslinked poly(vinyl alcohol) hydrogel growth factor release vehicle for wound healing applications

OpenAIRE

Bourke, Sharon L.; Al-Khalili, Mohammad; Briggs, Tonye; Michniak, Bozena B.; Kohn, Joachim; Poole-Warren, Laura A.

2003-01-01

The objective of this study was to develop and evaluate a hydrogel vehicle for sustained release of growth factors for wound healing applications. Hydrogels were fabricated using ultraviolet photo-crosslinking of acrylamide-functionalized nondegradable poly(vinyl alcohol) (PVA). Protein permeability was initially assessed using trypsin inhibitor (TI), a 21 000 MW model protein drug. TI permeability was altered by changing the solids content of the gel and by adding hydrophilic PVA fillers. As...

Properties of polyacrylic acid-coated silver nanoparticle ink for inkjet printing conductive tracks on paper with high conductivity

International Nuclear Information System (INIS)

Huang, Qijin; Shen, Wenfeng; Xu, Qingsong; Tan, Ruiqin; Song, Weijie

2014-01-01

Silver nanoparticles with a mean diameter of approximately 30 nm were synthesized by reduction of silver nitrate with triethanolamine in the presence of polyacrylic acid. Silver nanoparticle-based ink was prepared by dispersing silver nanoparticles into a mixture of water and ethylene glycol. The mechanism for the dispersion and aggregation of silver nanoparticles in ink is discussed. The strong electrostatic repulsions of the carboxylate anions of the adsorbed polyacrylic acid molecules disturbed the aggregation of metal particles in solutions with a high pH value (pH > 5). An inkjet printer was used to deposit this silver nanoparticle-based ink to form silver patterns on photo paper. The actual printing qualities of the silver tracks were then analyzed by variation of printing passes, sintering temperature and time. The results showed that sintering temperature and time are associated strongly with the conductivity of the inkjet-printed conductive patterns. The conductivity of printed patterns sintered at 150 °C increased to 2.1 × 10 7  S m −1 , which was approximately one third that of bulk silver. In addition, silver tracks on paper substrate also showed better electrical performance after folding. This study demonstrated that the resulting ink-jet printed patterns can be used as conductive tracks in flexible electronic devices. - Highlights: • An ink from silver nanoparticles coated with polyacrylic acid was prepared. • The ink was used for inkjet-printed tracks at varying printing parameters. • The conductivity of printed tracks sintered at 150 °C increased to 2.1 × 10 7  S/m. • Mechanism for dispersion and aggregation of the nanoparticles in ink is discussed

Properties of polyacrylic acid-coated silver nanoparticle ink for inkjet printing conductive tracks on paper with high conductivity

Energy Technology Data Exchange (ETDEWEB)

Huang, Qijin [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Shen, Wenfeng, E-mail: wfshen@nimte.ac.cn [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Xu, Qingsong [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Tan, Ruiqin [Faculty of Information Science and Engineering, Ningbo University, Ningbo, Zhejiang 315211 (China); Song, Weijie, E-mail: weijiesong@nimte.ac.cn [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China)

2014-10-15

Silver nanoparticles with a mean diameter of approximately 30 nm were synthesized by reduction of silver nitrate with triethanolamine in the presence of polyacrylic acid. Silver nanoparticle-based ink was prepared by dispersing silver nanoparticles into a mixture of water and ethylene glycol. The mechanism for the dispersion and aggregation of silver nanoparticles in ink is discussed. The strong electrostatic repulsions of the carboxylate anions of the adsorbed polyacrylic acid molecules disturbed the aggregation of metal particles in solutions with a high pH value (pH > 5). An inkjet printer was used to deposit this silver nanoparticle-based ink to form silver patterns on photo paper. The actual printing qualities of the silver tracks were then analyzed by variation of printing passes, sintering temperature and time. The results showed that sintering temperature and time are associated strongly with the conductivity of the inkjet-printed conductive patterns. The conductivity of printed patterns sintered at 150 °C increased to 2.1 × 10{sup 7} S m{sup −1}, which was approximately one third that of bulk silver. In addition, silver tracks on paper substrate also showed better electrical performance after folding. This study demonstrated that the resulting ink-jet printed patterns can be used as conductive tracks in flexible electronic devices. - Highlights: • An ink from silver nanoparticles coated with polyacrylic acid was prepared. • The ink was used for inkjet-printed tracks at varying printing parameters. • The conductivity of printed tracks sintered at 150 °C increased to 2.1 × 10{sup 7} S/m. • Mechanism for dispersion and aggregation of the nanoparticles in ink is discussed.

EUV lithographic radiation grafting of thermo-responsive hydrogel nanostructures

International Nuclear Information System (INIS)

Farquet, Patrick; Padeste, Celestino; Solak, Harun H.; Guersel, Selmiye Alkan; Scherer, Guenther G.; Wokaun, Alexander

2007-01-01

Nanostructures of the thermoresponsive poly(N-isopropyl acrylamide) (PNIPAAm) and of PNIPAAm-block-poly(acrylic acid) copolymers were produced on poly(tetrafluoroethylene-co-ethyelene) (ETFE) films using extreme ultraviolet (EUV) lithographic exposure with subsequent graft-polymerization. The phase transition of PNIPAAm nanostructures at the low critical solution temperature (LCST) at 32 deg. C was imaged by atomic force microscopy (AFM) phase contrast measurements in pure water. Results show a higher phase contrast for samples measured below the LCST temperature than for samples above the LCST, proving that the soft PNIPAAm hydrogel transforms into a much more compact conformation above the LCST. EUV lithographic exposures were combined with the reversible addition-fragment chain transfer (RAFT)-mediated polymerization using cyanoisopropyl dithiobenzoate (CPDB) as chain transfer agent to synthesize PNIPAAm block-copolymer nanostructures

An injectable and biodegradable hydrogel based on poly(α,β-aspartic acid) derivatives for localized drug delivery.

Science.gov (United States)

Lu, Caicai; Wang, Xiaojuan; Wu, Guolin; Wang, Jingjing; Wang, Yinong; Gao, Hui; Ma, Jianbiao

2014-03-01

An injectable hydrogel via hydrazone cross-linking was prepared under mild conditions without addition of cross-linker or catalyst. Hydrazine and aldehyde modified poly(aspartic acid)s were used as two gel precursors. Both of them are water-soluble and biodegradable polymers with a protein-like structure, and obtained by aminolysis reaction of polysuccinimide. The latter can be prepared by thermal polycondensation of aspartic acid. Hydrogels were prepared in PBS solution and characterized by different methods including gel content and swelling, Fourier transformed-infrared spectroscopy, and in vitro degradation experiment. A scanning electron microscope viewed the interior morphology of the obtained hydrogels, which showed porous three-dimensional structures. Different porous sizes were present, which could be well controlled by the degree of aldehyde substitution in precursor poly(aspartic acid) derivatives. The doxorubicin-loaded hydrogels were prepared and showed a pH-sensitive release profile. The release rate can be accelerated by decreasing the environmental pH from a physiological to a weak acidic condition. Moreover, the cell adhesion and growth behaviors on the hydrogel were studied and the polymeric hydrogel showed good biocompatibility. Copyright © 2013 Wiley Periodicals, Inc.

Modified maltodextrin-based hydrogel as a potential device for magnetic bio material

International Nuclear Information System (INIS)

Paulino, Alexandre T.; Guilherme, Marcos R.; Tambourgi, Elias B.; Muniz, Edvani C.

2009-01-01

A magnetic hydrogel was synthesized by a cross-linking/co-polymerization reaction of modified malto-dextrin and acrylamide in the presence of magnetite nanoparticles and persulfate as an initiator. The characterization of the formed hydrogel was accomplished by means of Fourier transform infrared spectroscopy (FT-IR), Moessbauer spectroscopy (MS), X-ray diffraction (XRD), and swelling rate (WR). The FT-IR analysis revealed that the malto-dextrin modification and the gelling process were efficient. From the MS and XRD analyses, it was concluded that the magnetite nanoparticles were efficiently embedded into the hydrogel structure and that the crystalline planes were different from those of the start material. WR decreased with the use of increasing amounts of magnetite in the hydrogel synthesis. In this sense, the electrostatic interactions decreased for increasing amounts of magnetite because the Fe 3+ ions neutralized the negative charges of the hydrogel structure. (author)

Super absorbent hydrogel composites as water retentive in soil; Hidrogeis compositos superabsorventes como retentores de agua no solo

Energy Technology Data Exchange (ETDEWEB)

Magalhaes, Antonio Savio G. [Faculdade de Educacao de Itapipoca, Curso de Quimica, UECE, Itapipoca, Ceara (Brazil); Almeida Neto, Manuel P. [Instituto Federal de Educacao, Ciencia e Tecnologia do RN - IFRN, Caico, RN (Brazil); Bezerra, Maslandia N.; Feitosa, Judith P.A., E-mail: judith@dqoi.ufc.br [Departamento de Quimica Organica e Inorganica, UFC, Fortaleza, Ceara (Brazil)

2011-07-01

Super absorbent hydrogels (SAP) were synthesized at room temperature, by the use of potassium persulfate as initiator, N,N'-methylene bis acrylamide (MBA) as crosslinking agent, and N,N,N',N'- tetramethylethylenediamine. Gels at the same conditions were prepared with 10% of minerals (bentonite or dolomite). The materials of bentonite series were obtained from acrylamide followed by hydrolysis with NaOH. The gels of dolomite series were prepared from the two co-monomers (acrylamide and acrylate). All SAPs were characterized by elemental microanalysis, FTIR, x-ray diffraction, SEM, and by swelling measurements in water. An intercalated composite was obtained with bentonite hydrogel. After hydrolysis an exfoliated nanocomposite was formed. The dolomite mineral was dispersed in the polymeric matrix. The swelling degrees of the SAPs with mineral were higher than those gels without it. This degree was 1,000 times the dry gel weight. Taking into account the amount of water needed to the process, the gel with dolomite is the most promising as soil conditioner. (author)

Poly(n-isopropylacrylamide)-based hydrogel coatings on magnetite nanoparticles via atom transfer radical polymerization

Energy Technology Data Exchange (ETDEWEB)

Frimpong, Reynolds A; Hilt, J Zach [Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States)], E-mail: hilt@engr.uky.edu

2008-04-30

Core magnetite (Fe{sub 3}O{sub 4}) nanoparticles have been functionalized with a model intelligent hydrogel system based on the temperature responsive polymer poly(n-isopropyl acrylamide) (PNIPAAm) to obtain magnetically responsive core-shell nanocomposites. Fe{sub 3}O{sub 4} nanoparticles were obtained from a one-pot co-precipitation method which provided either oleic acid (hydrophobic) or citric acid (hydrophilic) coated nanoparticles. Subsequent ligand exchange of these coatings with various bromine alkyl halides and a bromo silane provided initiating sites for functionalization with NIPAAm using atom transfer radical polymerization (ATRP). The bromine alkyl halides that were used were 2-bromo-2-methyl propionic acid (BMPA) and 2-bromopropionyl bromide (BPB). The bromo silane that was used was 3-bromopropyl trimethoxysilane (BPTS). The intelligent polymeric shell consists of NIPAAm crosslinked with poly(ethylene glycol) 400 dimethacrylate (PEG400DMA). Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) were used to confirm the presence of the polymeric shell. Dynamic light scattering (DLS) was used to characterize the nanocomposites for particle size changes with temperature. Their magnetic and temperature responsiveness show great promise for further biomedical applications. This platform for functionalizing magnetic nanoparticles with intelligent hydrogels promises to impact a wide range of medical and biological applications of magnetic nanoparticles.

Poly(n-isopropylacrylamide)-based hydrogel coatings on magnetite nanoparticles via atom transfer radical polymerization

International Nuclear Information System (INIS)

Frimpong, Reynolds A; Hilt, J Zach

2008-01-01

Core magnetite (Fe 3 O 4 ) nanoparticles have been functionalized with a model intelligent hydrogel system based on the temperature responsive polymer poly(n-isopropyl acrylamide) (PNIPAAm) to obtain magnetically responsive core-shell nanocomposites. Fe 3 O 4 nanoparticles were obtained from a one-pot co-precipitation method which provided either oleic acid (hydrophobic) or citric acid (hydrophilic) coated nanoparticles. Subsequent ligand exchange of these coatings with various bromine alkyl halides and a bromo silane provided initiating sites for functionalization with NIPAAm using atom transfer radical polymerization (ATRP). The bromine alkyl halides that were used were 2-bromo-2-methyl propionic acid (BMPA) and 2-bromopropionyl bromide (BPB). The bromo silane that was used was 3-bromopropyl trimethoxysilane (BPTS). The intelligent polymeric shell consists of NIPAAm crosslinked with poly(ethylene glycol) 400 dimethacrylate (PEG400DMA). Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) were used to confirm the presence of the polymeric shell. Dynamic light scattering (DLS) was used to characterize the nanocomposites for particle size changes with temperature. Their magnetic and temperature responsiveness show great promise for further biomedical applications. This platform for functionalizing magnetic nanoparticles with intelligent hydrogels promises to impact a wide range of medical and biological applications of magnetic nanoparticles

Gamma ray-induced synthesis of hyaluronic acid/chondroitin sulfate-based hydrogels for biomedical applications

International Nuclear Information System (INIS)

Zhao, Linlin; Gwon, Hui-Jeong; Lim, Youn-Mook; Nho, Young-Chang; Kim, So Yeon

2015-01-01

Hyaluronic acid (HA)/chondroitin sulfate (CS)/poly(acrylic acid) (PAAc) hydrogel systems were synthesized by gamma-ray irradiation without the use of additional initiators or crosslinking agents to achieve a biocompatible hydrogel system for skin tissue engineering. HA and CS derivatives with polymerizable residues were synthesized. Then, the hydrogels composed of glycosaminoglycans, HA, CS, and a synthetic ionic polymer, PAAc, were prepared using gamma-ray irradiation through simultaneous free radical copolymerization and crosslinking. The physicochemical properties of the HA/CS/PAAc hydrogels having various compositions were investigated to evaluate their feasibility as artificial skin substitutes. The gel fractions of the HA/CS/PAAc hydrogels increased in absorbed doses up to 15 kGy, and they exhibited 91–93% gel fractions under 15 kGy radiation. All of the HA/CS/PAAc hydrogels exhibited relatively high water contents of over 90% and reached an equilibrium swelling state within 24 h. The enzymatic degradation kinetics of the HA/CS/PAAc hydrogels depended on both the concentration of the hyaluronidase solution and the ratio of HA/CS/PAAc. The in vitro drug release profiles of the HA/CS/PAAc hydrogels were significantly influenced by the interaction between the ionic groups in the hydrogels and the ionic drug molecules as well as the swelling of the hydrogels. From the cytotoxicity results of human keratinocyte (HaCaT) cells cultured with extracts of the HA/CS/PAAc hydrogels, all of the HA/CS/PAAc hydrogel samples tested showed relatively high cell viabilities of more than 82%, and did not induce any significant adverse effects on cell viability. - Highlights: • HA/CS/PAAc hydrogels were synthesized by gamma-ray irradiation. • HA/CS/PAAc hydrogels exhibited 91–93% gel fractions under 15 kGy radiation. • All of the HA/CS/PAAc hydrogels exhibited high water contents of over 90%. • The hydrogel samples showed relatively high cell viabilities of more than

Synthesis and characterization of arginine-NIPAAm hybrid hydrogel as wound dressing: In vitro and in vivo study.

Science.gov (United States)

Wu, De-Qun; Zhu, Jie; Han, Hua; Zhang, Jun-Zhi; Wu, Fei-Fei; Qin, Xiao-Hong; Yu, Jian-Yong

2018-01-01

A multi-functional hybrid hydrogel P(M-Arg/NIPAAm) with temperature response, anti-protein adsorption and antibacterial properties was prepared and applied as wound dressing. The hydrogel was carried out by free radical copolymerization of methacrylate arginine (M-Arg) and N-isopropyl acrylamide (NIPAAm) monomers using N,N'-methylene bisacrylamide as a crosslinker, and ammonium persulfate/N,N,N', N'-tetramethylethylenediamine as the redox initiator. To endow the antimicrobial property, chlorhexidine diacetate (CHX) was preloaded into the hydrogel and polyhexamethylene guanidine phosphate (PHMG) was grafted on the hydrogel surface, respectively. The antimicrobial property of two series of hydrogels was evaluated and compared. The successful synthesis of M-Arg, PHMG and hydrogels was proved by 13 C NMR, 1 H NMR and FTIR spectroscopy. The hydrogel morphology characterized by scanning electron microscopy confirmed that the homogeneous porous and interconnected structures of the hydrogels. The swelling, protein adsorption property, in vitro release of CHX, antimicrobial assessment, cell viability as well as in vivo wound healing in a mouse model were studied. The results showed the nontoxicity and antimicrobial P(M-Arg/NIPAAm) hydrogel accelerated the full-thickness wound healing process and had the potential application in wound dressing. Despite the zwitterionic characteristic and biocompatible property of arginine based hydrogels, the brittle behavior and non-transparency still remain as a significant problem for wound dressing. Furthermore promoting the antibacterial property of the zwitterionic hydrogel is also necessary to prevent the bacterial colonization and subsequent wound infection. Therefore, we created a hybrid hydrogel combined methacrylate arginine (M-Arg) and N-isopropyl acrylamide (NIPAAm). NIPAAm improves transparency and mechanical property as well as acts as a temperature-response drug release system. Additionally, chlorhexidine (CHX) was preloaded

Patented Techniques for Acrylamide Mitigation in High-Temperature Processed Foods

DEFF Research Database (Denmark)

Mariotti, Salome; Pedreschi, Franco; Antonio Carrasco, José

2011-01-01

Heating foods has many advantages since it adds taste, color, texture and minimizes harmful germs, among others. Flavor and aroma compounds are produced via the Maillard reaction, where various hazardous com-pounds may form as well, such as acrylamide. Maillard reaction is believed to be the main...... for acrylamide reduction in foods processed at high temperatures are mentioned and briefly analyzed in order to develop new mitigation techniques for acrylamide in different food matrixes.......Heating foods has many advantages since it adds taste, color, texture and minimizes harmful germs, among others. Flavor and aroma compounds are produced via the Maillard reaction, where various hazardous com-pounds may form as well, such as acrylamide. Maillard reaction is believed to be the main...... route for acrylamide for-mation between reducing sugars (glucose and fructose), sucrose, and the amino acid asparagine, and, consequently, a variety of technologies have been developed to reduce acrylamide concentration in thermally processed foods based ei-ther on: (i) Changing process parameters (e...

Phase Transition of Poly(acrylic acid-co-N-isopropylacrylamide) Core-shell Nanogels

Science.gov (United States)

Liu, Xiao-bing; Zhou, Jian-feng; Ye, Xiao-dong

2012-08-01

A series of poly(acrylic acid) macromolecular chain transfer agents with different molecular weights were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and characterized by 1H NMR and gel permeation chromatography. Multiresponsive core-shell nanogels were prepared by dispersion polymerization of N-isopropylacrylamide in water using these poly(potassium acrylate) macro-RAFT agents as the electrosteric stabilizer. The size of the nanogels decreases with the amount of the macro-RAFT agent, indicating that the surface area occupied by per polyelectrolyte group is a critical parameter for stabilizing the nanogels. The volume phase transition and the zeta potentials of the nanogels in aqueous solutions were studied by dynamic light scattering and zetasizer analyzer, respectively.

One-step routes from di- and triblock copolymer precursors to hydrophilic nanoporous poly(acrylic acid)-b-polystyrene

DEFF Research Database (Denmark)

Guo, Fengxiao; Jankova Atanasova, Katja; Schulte, Lars

2008-01-01

Nanoporous polystyrene with hydrophilic pores was prepared from di- and triblock copolymer precursors. The precursor material was either a poly(tert-butyl acryl ate)-b-polystyrene (PtBA-b-PS) diblock copolymer synthesized by atom transfer radical polymerization (ATRP) or a polydimethylsiloxane......-b-poly(tertbutyl acrylate)-b-polystyrene (PDMS-b-PtBA-b-PS) triblock copolymer synthesized by a combination of living anionic polymerization and ATRP. In the latter copolymer, PS was the matrix and mechanically stable component, PtBA was converted by acidic deprotection to hydrophilic poly(acrylic acid) (PAA) providing...

Natural fibers for hydrogels production and their applications in agriculture

Directory of Open Access Journals (Sweden)

Liliana Serna Cock

2017-10-01

Full Text Available This paper presents a review on hydrogels applied to agriculture emphasizing on the use of natural fibers. The objectives were to examine, trends in research addressed to identify natural fibers used in hydrogels development and methods for modifying natural fibers, understand factors which determine the water retention capacity of a hydrogel. Consequently, this paper shows some methodologies used to evaluate the hydrogels efficiency and to collect in tables, relevant information in relation to methods of natural fibers modification and hydrogel synthesis. It was found that previous research focused on hydrogels development processed with biodegradable polymers such as starch, chitosan and modified natural fibers, cross-linked with potassium acrylate and acrylamide, respectively. In addition, current researches aimed to obtaining hydrogels with improved properties, which have allowed a resistance to climatic variations and soil physicochemical changes, such as pH, presence of salts, temperature and composition. In fact, natural fibers such as sugarcane, agave fiber and kapok fiber, modified with maleic anhydride, are an alternative to obtain hydrogels due to an increasing of mechanical properties and chemically active sites. However, the use of natural nanofibers in hydrogels, has been a successful proposal to improve hydrogels mechanical and swelling properties, since they give to material an elasticity and rigidity properties. A hydrogel efficiency applied to soil, is measured throughout properties as swellability, mechanical strength, and soil water retention. It was concluded that hydrogels, are an alternative to the current needs for the agricultural sector.

Radiolysis of poly(acrylic acid) in aqueous solution

Science.gov (United States)

Ulanski, Piotr; Bothe, Eberhard; Hildenbrand, Knut; Rosiak, Janusz M.; von Sonntag, Clemens

1995-02-01

Poly(acrylic acid), PAA, reacts with OH-radicals yielding -CHCH(CO 2H)- (β-radicals) and -CH 2C(CO 2H)- (α-radicals) in a ratio of approximately 2:1. This estimate is based on pulse radiolysis data where the absorption spectrum of the PAA-radicals was compared with the spectra of α-radicals from model systems. The β-radicals convert slowly into α-radicals ( k = 0.7 s -1 at pH 10). This process has also been observed by ESR. At PAA-concentrations of 10 -2 mol dm -3 chain scission dominates over other competing reactions except at low pH. The rate of chain scission was followed by pulse conductometry and in the pH range 7-9 k = 4 × 10 -2s -1 was observed. Oxygen reacts with PAA-radicals with k = 3.1 × 10 8 dm 3 mol -1 s -1 at pH 3.5 and k = 1.0 × 10 8 dm 3 mol -1 s -1 at pH 10. The corresponding peroxyl radicals undergo slow intramolecular H-transfer yielding a UV-absorbing product whose properties are that of 1,3-diketones.

A review of acrylamide: an industry perspective on research, analysis, formation, and control.

Science.gov (United States)

Taeymans, Dominique; Wood, John; Ashby, Peter; Blank, Imre; Studer, Alfred; Stadler, Richard H; Gondé, Pierre; Van Eijck, Paul; Lalljie, Sam; Lingnert, Hans; Lindblom, Marianne; Matissek, Reinhard; Müller, Detflef; Tallmadge, Dan; O'Brien, John; Thompson, Sara; Silvani, David; Whitmore, Tricia

2004-01-01

Acrylamide is a synthetic monomer with a wide scope of industrial applications, mainly as a precursor in the production of several polymers, such as polyacrylamide. The main uses of polyacrylamides are in water and wastewater treatment processes, pulp and paper processing, and mining and mineral processing. The announcement by the Swedish National Food Administration in April 2002 of the presence of acrylamide predominantly in heat-treated carbohydrate-rich foods sparked intensive investigations into acrylamide, encompassing the occurrence, chemistry, agricultural practices, and toxicology, in order to establish if there is a potential risk to human health from the presence of this contaminant in the human diet. The link of acrylamide in foods to the Maillard reaction and, in particular, to the amino acid asparagine has been a major step forward in elucidating the first feasible chemical route of formation during the preparation and processing of food. Other probably minor pathways have also been proposed, including acrolein and acrylic acid. This review addresses the analytical and mechanistic aspects of the acrylamide issue and summarizes the progress made to date by the European food industries in these key areas. Essentially, it presents experimental results generated under laboratory model conditions, as well as under actual food processing conditions covering different food categories, such as potatoes, biscuits, cereals, and coffee. Since acrylamide formation is closely linked to food composition, factors such as the presence of sugars and availability of free amino acids are also considered. Many new findings that contribute towards a better understanding of the formation and presence of acrylamide in foods are presented. Many national authorities across the world are assessing the dietary exposure of consumers to acrylamide, and scientific projects have commenced to gather new information about the toxicology of acrylamide. These are expected to provide

Fabrication of Hyaluronan-Poly(vinylphosphonic acid-Chitosan Hydrogel for Wound Healing Application

Directory of Open Access Journals (Sweden)

Dang Hoang Phuc

2016-01-01

Full Text Available A new hydrogel made of hyaluronan, poly(vinylphosphonic acid, and chitosan (HA/PVPA/CS hydrogel was fabricated and characterized to be used for skin wound healing application. Firstly, the component ratio of hydrogel was studied to optimize the reaction effectiveness. Next, its microstructure was observed by light microscope. The chemical interaction in hydrogel was evaluated by nuclear magnetic resonance spectroscopy and Fourier transform-infrared spectroscopy. Then, a study on its degradation rate was performed. After that, antibacterial activity of the hydrogel was examined by agar diffusion method. Finally, in vivo study was performed to evaluate hydrogel’s biocompatibility. The results showed that the optimized hydrogel had a three-dimensional highly porous structure with the pore size ranging from about 25 µm to less than 125 µm. Besides, with a degradation time of two weeks, it could give enough time for the formation of extracellular matrix framework during remodeling stages. Furthermore, the antibacterial test showed that hydrogel has antimicrobial activity against E. coli. Finally, in vivo study indicated that the hydrogel was not rejected by the immune system and could enhance wound healing process. Overall, HA/PVPA/CS hydrogel was successfully fabricated and results implied its potential for wound healing applications.

Removal of some basic dyes by poly (Vinyl Alcohol/ acrylic acid)Hydrogel

International Nuclear Information System (INIS)

Hegazy, S.A.; Abdel-AAl, S.E.; Abdel-Rehim, H.A.; Khalifa, N.A.; El-Hosseiny, E.M.

2000-01-01

A study has made on the preparation and properties of poly (vinyl alcohol/ acrylic acid) hydrogel for the purpose of removal of cationic dyes from aqueous solutions. The effect of dose and monomer concentration on the uptake property of the hydrogel toward dye was studied. The uptake of basic methylene blue-9 dye with PVA/AAc was studied by the batch adsorption technique. The effect of pH on the dye uptake was demonstrated to find out that the suitable pH for maximum uptake occurred at pH 5. It was observed that as the concentration of dye is increased the dye uptake decreased. Furthermore, the uptake of dye by hydrogels increased as the temperature was elevated. The recovery of dye adsorbed is possible by treating the hydrogel with 5% HCl. The results obtained suggested this hydrogel possessed good removal properties towards basic methylene blue-9 dye, and this suggests that such hydrogels could be acceptable for practical uses

Gum ghatti and poly(acrylamide-co-acrylic acid) based biodegradable hydrogel-evaluation of the flocculation and adsorption properties

CSIR Research Space (South Africa)

Mittal, H

2015-10-01

Full Text Available removal of cationic dyes from the aqueous solutions and it was found to adsorb 96% of malachite green and 99% of methyl violet. Finally, the hydrogel polymer was subjected to biodegradation using the composting method and 91.77% degradation was achieved...

Surface-modified silk hydrogel containing hydroxyapatite nanoparticle with hyaluronic acid-dopamine conjugate.

Science.gov (United States)

Kim, Hyung Hwan; Park, Jong Bo; Kang, Min Ji; Park, Young Hwan

2014-09-01

Silk fibroin/hydroxyapatite (SF/HAp) composite hydrogels were fabricated in this study, having different HAp contents (0-33 wt%) in SF matrix hydrogel. Surface modification of HAp nanoparticle with hyaluronic acid (HA)-dopamine (DA) conjugate improved a dispersibility of HAp in aqueous SF solution due to its negatively charged surface and therefore, fabrication of the SF composite hydrogel having HAp nanoparticles inside could be possible. Zeta potential of surface-modified HAP was examined by ELS. It demonstrates that surface of HAp was well modified to a negative charge with HA-DA. Morphological structure of SF hydrogel containing surface-modified HAp was examined by FE-SEM for analyzing pore structure of hydrogel and deposition of HAp nanoparticle in SF hydrogel. It was found that HAp nanoparticles were uniformly deposited on the pore wall of SF hydrogel. Structural characteristics of SF/HAp composite hydrogel was performed using X-ray diffraction and FT-IR analysis. It was found that β-sheet crystal conformation of SF was significantly influenced by the HAp content during gelation of a mixture of SF and HAp. As a result of MTT assay, the SF/HAp composite hydrogel showed excellent cell proliferation ability. Therefore, it is expected that SF hydrogel containing HAp nanoparticles has a high potential as bone regeneration scaffold. Copyright © 2014 Elsevier B.V. All rights reserved.

Quartz Microbalance Sensor for the Detection of Acrylamide

Directory of Open Access Journals (Sweden)

Christoph A. Schalley

2004-10-01

Full Text Available Abstract: Several macrocycles of the Hunter-Vögtle type have been identified as superior host compounds for the detection of small amounts of acrylamide. When coated onto the surface of a quartz microbalance, these compounds serve as highly sensitive and selective sensor-active layers for their use in electronic noses. In this study, differently substituted macrocycles were investigated including an open-chain analogue and a catenane. Their structure and functional groups are correlated with their observed affinities to acrylamide and related acids and amides. The much smaller response of the open-chain compound and the almost absent sensor response of the catenane suggest that binding occurs within the cavity of the macrocycle. Theoretical calculations agree well with the experimental data even though they do not yet take into account the arrangement of the macrocycles in the sensor-active layer. The lower detection limit of acrylamide is 10 parts per billion (ppb, which is impressively low for this type of sensor. Other related compounds such as acrylic acid, propionamide, or propionic acid show no or significantly lower affinities to the macrocycles in these concentration ranges.

The synthesis and characterization of hydrogel chitosan-alginate with the addition of plasticizer lauric acid for wound dressing application

Science.gov (United States)

Izak Rudyardjo, Djony; Wijayanto, Setiawan

2017-05-01

The writers conducted a study about the synthesis and characterization of hydrogel chitosan-alginate by addition plasticizer lauric acid for wound dressing application. The purpose was to find out the impact of lauric acid concentration variation on hydrogel chitosan-alginate to get the best mechanical and physical properties to be applied as wound dressing in accordance with existing standards. This study used commercially chitosan from extract of shells crab, commercially-available alginate from the extract of sargassum sp, and commercial lauric acid from palm starch. The addition of lauric acid was aimed to repair mechanical properties of hydrogel. The composition of chitosan-alginate is 4:1 (v/v), while the lauric acid concentration variations are 0%, 1%, 2%, 3%, 4%, and 5% w/v. The characterization of mechanical properties test (Tensile strength and Elongation at break) at hydrogel showed the hydrogel chitosan-alginate-lauric acid have the characteristic which meets the standard of mechanical properties for human skin. The best performance of hydrogel chitosan-alginate-lauric acid was obtained by increasing luric acid concentration by 4%, which has a thickness value of 125.46±0.63 µm, elongation 28.89±1.01 %, tensile strength (9.01±0.65) MPa, and ability to absorb liquids (601.45 ±1.24) %.

3D bioprinting of methacrylated hyaluronic acid (MeHA) hydrogel with intrinsic osteogenicity.

Science.gov (United States)

Poldervaart, Michelle T; Goversen, Birgit; de Ruijter, Mylene; Abbadessa, Anna; Melchels, Ferry P W; Öner, F Cumhur; Dhert, Wouter J A; Vermonden, Tina; Alblas, Jacqueline

2017-01-01

In bone regenerative medicine there is a need for suitable bone substitutes. Hydrogels have excellent biocompatible and biodegradable characteristics, but their visco-elastic properties limit their applicability, especially with respect to 3D bioprinting. In this study, we modified the naturally occurring extracellular matrix glycosaminoglycan hyaluronic acid (HA), in order to yield photo-crosslinkable hydrogels with increased mechanical stiffness and long-term stability, and with minimal decrease in cytocompatibility. Application of these tailor-made methacrylated hyaluronic acid (MeHA) gels for bone tissue engineering and 3D bioprinting was the subject of investigation. Visco-elastic properties of MeHA gels, measured by rheology and dynamic mechanical analysis, showed that irradiation of the hydrogels with UV light led to increased storage moduli and elastic moduli, indicating increasing gel rigidity. Subsequently, human bone marrow derived mesenchymal stromal cells (MSCs) were incorporated into MeHA hydrogels, and cell viability remained 64.4% after 21 days of culture. Osteogenic differentiation of MSCs occurred spontaneously in hydrogels with high concentrations of MeHA polymer, in absence of additional osteogenic stimuli. Addition of bone morphogenetic protein-2 (BMP-2) to the culture medium further increased osteogenic differentiation, as evidenced by increased matrix mineralisation. MeHA hydrogels demonstrated to be suitable for 3D bioprinting, and were printed into porous and anatomically shaped scaffolds. Taken together, photosensitive MeHA-based hydrogels fulfilled our criteria for cellular bioprinted bone constructs within a narrow window of concentration.

3D bioprinting of methacrylated hyaluronic acid (MeHA hydrogel with intrinsic osteogenicity.

Directory of Open Access Journals (Sweden)

Michelle T Poldervaart

Full Text Available In bone regenerative medicine there is a need for suitable bone substitutes. Hydrogels have excellent biocompatible and biodegradable characteristics, but their visco-elastic properties limit their applicability, especially with respect to 3D bioprinting. In this study, we modified the naturally occurring extracellular matrix glycosaminoglycan hyaluronic acid (HA, in order to yield photo-crosslinkable hydrogels with increased mechanical stiffness and long-term stability, and with minimal decrease in cytocompatibility. Application of these tailor-made methacrylated hyaluronic acid (MeHA gels for bone tissue engineering and 3D bioprinting was the subject of investigation. Visco-elastic properties of MeHA gels, measured by rheology and dynamic mechanical analysis, showed that irradiation of the hydrogels with UV light led to increased storage moduli and elastic moduli, indicating increasing gel rigidity. Subsequently, human bone marrow derived mesenchymal stromal cells (MSCs were incorporated into MeHA hydrogels, and cell viability remained 64.4% after 21 days of culture. Osteogenic differentiation of MSCs occurred spontaneously in hydrogels with high concentrations of MeHA polymer, in absence of additional osteogenic stimuli. Addition of bone morphogenetic protein-2 (BMP-2 to the culture medium further increased osteogenic differentiation, as evidenced by increased matrix mineralisation. MeHA hydrogels demonstrated to be suitable for 3D bioprinting, and were printed into porous and anatomically shaped scaffolds. Taken together, photosensitive MeHA-based hydrogels fulfilled our criteria for cellular bioprinted bone constructs within a narrow window of concentration.

Cellulose nanocrystal-filled poly(acrylic acid) nanocomposite fibrous membranes

International Nuclear Information System (INIS)

Lu Ping; Hsieh, You-Lo

2009-01-01

Nanocomposite fibrous membranes have been fabricated by electrospinning cellulose nanocrystal (CNC)-loaded poly(acrylic acid) (PAA) ethanol mixtures. Incorporating CNC in PAA significantly reduced fiber diameters and improved fiber uniformity. The average diameters of the as-spun nanocomposite fibers were significantly reduced from 349 nm to 162 nm, 141 nm, 90 nm and 69 nm at 5%, 10%, 15% and 20% CNC loading (by weight of a constant 4% PAA solution), respectively. CNC was well dispersed in the fibers as isolated rods oriented along the fiber axis and as spheres in the PAA matrix. The Young modulus and stress of the PAA/CNC nanocomposite fibers were significantly improved with increasing CNC loadings by up to 35-fold and 16-fold, respectively. Heat-induced esterification between the CNC surface hydroxyls and PAA carboxyl groups produced covalent crosslinks at the CNC-PAA interfaces, rendering the nanocomposite fibrous membranes insoluble in water, more thermally stable and far more superior in tensile strength. With 20% CNC, the crosslinked nanocomposite fibrous membrane exhibited a very impressive 77-fold increase in modulus and 58-fold increase in stress.

Influence of polyacrylic acid nanoparticles on the elastic properties of RBCs membranes in patients with diabetes mellitus type 2

Czech Academy of Sciences Publication Activity Database

Melnikova, G.B.; Kuzhel, N.S.; Tolstaya, T.N.; Konstantinova, E.E.; Drozd, E.S.; Shisko, O.N.; Mokhort, T.G.; Antonova, N.; Říha, Pavel; Kowalczuk, A.; Koseva, N.

2015-01-01

Roč. 29, č. 4 (2015), s. 12-19 ISSN 1313-2458 Institutional support: RVO:67985874 Keywords : red blood cells * nanoparticles * poly(acrylic acid) * elasticity modulus * atomic force microscopy Subject RIV: BK - Fluid Dynamics http://www.imbm.bas.bg/biomechanics/uploads/Archive2015-4/12-19_Melnikova-Konstantinova_et%20al_abstract-1_18.12.15.pdf

Effect of Chemical Washing Pre-treatment of Empty Fruit Bunch (EFB) biochar on Characterization of Hydrogel Biochar composite as Bioadsorbent

Science.gov (United States)

Meri, N. H.; Alias, A. B.; Talib, N.; Rashid, Z. A.; Wan, W. A.; Ghani, Ab Karim

2018-05-01

Hydrogel biochar composite (HBC) is a recent interest among researchers because of the hydrophilic characteristic which can adsorb chemical fluid and showed a versatile potential as adsorbent in removing hazardous material in wastewater and gas stream. In this study, the effect of chemical washing pre-treatment by using two different type of chemical agent Hydrochloric Acid (HCL) and Hydrogen Peroxide (H2O2) was analysed and investigated. The raw EFB biochar was prepared using microwave assisted pyrolysis under 1000W for 30 min under N2 flow with 150 mL/min. To improve the adsoprtion ability, the EFB biochar has been chemical washed pre-treatment with Hydrochloric Acid (HCl) and Hydrogen Peroxide (H2O2) before polymerization process with acrylamide (AAm) as monomer, N,N’-methylenebisacrylamide (MBA) as crosslinker and ammonium persulfate (APS) as initiator. The characterization has studied by using Fourier transform infrared spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). FTIR result shows that, the formation of Raw EFB to Hydrogel Biochar Composite (Raw EFB > EFB Biochar > Treated Biochars (HCl & H2O2) > Hydrogel Biochar Composite) have changed in functional group. For DSC result it shows that the thermal behaviour of all samples is endothermic process and have high thermal resistance.

Supermacroporous chemically cross-linked poly(aspartic acid) hydrogels.

Science.gov (United States)

Gyarmati, Benjámin; Mészár, E Zsuzsanna; Kiss, Lóránd; Deli, Mária A; László, Krisztina; Szilágyi, András

2015-08-01

Chemically cross-linked poly(aspartic acid) (PASP) gels were prepared by a solid-liquid phase separation technique, cryogelation, to achieve a supermacroporous interconnected pore structure. The precursor polymer of PASP, polysuccinimide (PSI) was cross-linked below the freezing point of the solvent and the forming crystals acted as templates for the pores. Dimethyl sulfoxide was chosen as solvent instead of the more commonly used water. Thus larger temperatures could be utilized for the preparation and the drawback of increase in specific volume of water upon freezing could be eliminated. The morphology of the hydrogels was characterized by scanning electron microscopy and interconnectivity of the pores was proven by the small flow resistance of the gels. Compression tests also confirmed the interconnected porous structure and the complete re-swelling and shape recovery of the supermacroporous PASP hydrogels. The prepared hydrogels are of interest for several biomedical applications as scaffolding materials because of their cytocompatibility, controllable morphology and pH-responsive character. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Raman spectroscopy of 2-hydroxyethyl methacrylate-acrylamide copolymer using gamma irradiation for crosslinking

International Nuclear Information System (INIS)

Goheen, Steven C.; Saunders, Rachel M.; Davis, Rachel M.; Harvey, Scott D.; Olsen, Peter C.

2006-01-01

A copolymer hydrogel was made by mixing acrylamide and 2-hydroxyethyl methacrylate monomers in water and polymerizing with gamma irradiation. The progress of polymerization and the vibrational structure of the hydrogel was examined using Raman spectroscopy. Raman spectra indicated that the co-polymer has a molecular structure different from polyacrylamide or the individual monomers. The Raman data also indicate the presence of crosslinking at the C=O, NH2 and OH side chains. The spectra further suggest the continuous lengthening of the backbone of the polymers with increasing gamma dose. This is shown as the increase in C-C modes as C=C vibrations decrease. Raman spectra changed most dramatically as the monomer mixture became a gel at a dose of approximately 320 Gy. Spectral differences were subtler with doses exceeding 640 Gy, although chain lengthening continued beyond 1500 Gy. Potential applications of the copolymer hydrogel include reconstructive tissue as well as a standard material for radiation protection dosimetry. Results are discussed in relation to other potential applications of this polymer and dose-dependent changes in the Raman spectrum

The self-crosslinking smart hyaluronic acid hydrogels as injectable three-dimensional scaffolds for cells culture.

Science.gov (United States)

Bian, Shaoquan; He, Mengmeng; Sui, Junhui; Cai, Hanxu; Sun, Yong; Liang, Jie; Fan, Yujiang; Zhang, Xingdong

2016-04-01

Although the disulfide bond crosslinked hyaluronic acid hydrogels have been reported by many research groups, the major researches were focused on effectively forming hydrogels. However, few researchers paid attention to the potential significance of controlling the hydrogel formation and degradation, improving biocompatibility, reducing the toxicity of exogenous and providing convenience to the clinical operations later on. In this research, the novel controllable self-crosslinking smart hydrogels with in-situ gelation property was prepared by a single component, the thiolated hyaluronic acid derivative (HA-SH), and applied as a three-dimensional scaffold to mimic native extracellular matrix (ECM) for the culture of fibroblasts cells (L929) and chondrocytes. A series of HA-SH hydrogels were prepared depending on different degrees of thiol substitution (ranging from 10 to 60%) and molecule weights of HA (0.1, 0.3 and 1.0 MDa). The gelation time, swelling property and smart degradation behavior of HA-SH hydrogel were evaluated. The results showed that the gelation and degradation time of hydrogels could be controlled by adjusting the component of HA-SH polymers. The storage modulus of HA-SH hydrogels obtained by dynamic modulus analysis (DMA) could be up to 44.6 kPa. In addition, HA-SH hydrogels were investigated as a three-dimensional scaffold for the culture of fibroblasts cells (L929) and chondrocytes cells in vitro and as an injectable hydrogel for delivering chondrocytes cells in vivo. These results illustrated that HA-SH hydrogels with controllable gelation process, intelligent degradation behavior, excellent biocompatibility and convenient operational characteristics supplied potential clinical application capacity for tissue engineering and regenerative medicine. Copyright © 2016 Elsevier B.V. All rights reserved.

Molecular Dynamics Simulations of Adsorption of Poly(acrylic acid) and Poly(methacrylic acid) on Dodecyltrimethylammonium Chloride Micelle in Water: Effect of Charge Density.

Science.gov (United States)

Sulatha, Muralidharan S; Natarajan, Upendra

2015-09-24

We have investigated the interaction of dodecyltrimethylammonium chloride (DoTA) micelle with weak polyelectrolytes, poly(acrylic acid) and poly(methacrylic acid). Anionic as well as un-ionized forms of the polyelectrolytes were studied. Polyelectrolyte-surfactant complexes were formed within 5-11 ns of the simulation time and were found to be stable. Association is driven purely by electrostatic interactions for anionic chains whereas dispersion interactions also play a dominant role in the case of un-ionized chains. Surfactant headgroup nitrogen atoms are in close contact with the carboxylic oxygens of the polyelectrolyte chain at a distance of 0.35 nm. In the complexes, the polyelectrolyte chains are adsorbed on to the hydrophilic micellar surface and do not penetrate into the hydrophobic core of the micelle. Polyacrylate chain shows higher affinity for complex formation with DoTA as compared to polymethacrylate chain. Anionic polyelectrolyte chains show higher interaction strength as compared to corresponding un-ionized chains. Anionic chains act as polymeric counterion in the complexes, resulting in the displacement of counterions (Na(+) and Cl(-)) into the bulk solution. Anionic chains show distinct shrinkage upon adsorption onto the micelle. Detailed information about the microscopic structure and binding characteristics of these complexes is in agreement with available experimental literature.

Adsorption Properties of PVA/PAA/clay Composite Hydrogel Synthesized by Gamma Radiation and its Application in Removal of Crystal Violet Dye from Its Aqueous Solution

International Nuclear Information System (INIS)

Kamal, H.; El-Sayed, A. Hegazy; Mohamed, M.M.; Sabaa, M.W.; El-Dessouky, M.M.

2014-01-01

Copolymer hydrogels composed of Poly vinyl alcohol (PVA) and Poly acrylic acid (PAA) were prepared by γ-irradiation in the presence of N,N’ methylene bis acrylamide (MBAM) as crosslinking agent or bentonite clay. The copolymers were characterized by FTIR and SEM. The dye adsorption experiments for Crystal Violet dye (CV) were carried out by using bath procedure. UV-visible absorption spectroscopy was used to determine the adsorption behavior. The effect of different copolymer composition, clay concentration, ph, contact time, adsorbent dose, initial dye concentration, and adsorption temperature were investigated to obtain the best experimental conditions. The adsorption equilibrium was attained after about 24h. of contact time. It was found that the adsorption process was correlated with Freundlich isotherm equation. Kinetic and thermodynamic studies of CV dye onto the prepared hydrogels were also evaluated

Influence of retinoic acid on mesenchymal stem cell differentiation in amyloid hydrogels

Directory of Open Access Journals (Sweden)

Reeba Susan Jacob

2015-12-01

Full Text Available This paper presents data related to the research article “Self healing hydrogels composed of amyloid nano fibrils for cell culture and stem cell differentiation” [1]. Here we probed the collective influence of all-trans retinoic acid (RA and substrate properties (amyloid hydrogel on human mesenchymal stem cell (hMSC differentiation. Stem cells were cultured on soft amyloid hydrogels [1,2] in the presence and absence of matrix encapsulated RA. The cell morphology was imaged and assessed via quantification of circularity. Further immunostaining and quantitative real time PCR was used to quantify various markers of differentiation in the neuronal lineage.

Radiolysis of poly(acrylic acid) in aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Ulanski, P [Max-Planck-Institut fuer Strahlenchemie, Muelheim an der Ruhr (Germany); [Politechnika Lodzka, Lodz (Poland); Bothe, E; Hildenbrand, K; Sonntag, C von [Max-Planck-Institut fuer Strahlenchemie, Muelheim an der Ruhr (Germany); Rosiak, J M [Politechnika Lodzka, Lodz (Poland)

1995-10-01

Poly(acrylic acid), PAA, reacts with OH-radicals yielding -CH-CH(CO{sub 2}H)- ({beta}-radicals) and -CH{sub 2}-C(CO{sub 2}H)-({alpha}-radicals) in a ratio of approximately 2:1. This estimate is based on pulse radiolysis data where the absorption spectrum of the PAA-radicals was compared with the spectra of {alpha}-radicals from model systems. The {beta}-radicals convert slowly into {alpha}-radicals (k = 0.7s {sup -1} at pH 10). This process has also been observed by ESR. At PAA-concentrations of 10{sup -2} mol dm{sup -3} chain scission dominates over other competing reactions except at low pH. The rate of chain scission was followed by pulse conductometry and in the pH range 7-9 k = 4 x 10{sup -2}s{sup -1} was observed. Oxygen reacts with PAA-radicals with k = 3.1 x 10{sup 8} dm{sup 3} mol{sup -1} s{sup -1} at pH 3.5 and k = 1.0 x 10{sup 8} dm{sup 3} mol{sup -1} s{sup -1} at pH 10. The corresponding peroxyl radicals undergo slow intramolecular H-transfer yielding a UV-absorbing product whose properties are that of 1,3-diketones. (Author).

Preparation and properties of EDC/NHS mediated crosslinking poly (gamma-glutamic acid)/epsilon-polylysine hydrogels

Energy Technology Data Exchange (ETDEWEB)

Hua, Jiachuan [Key Laboratory of Advanced Textile Composites, Tianjin Polytechnic University, Ministry of Education, Tianjin 300387 (China); School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Li, Zheng, E-mail: lizheng_nx@163.com [Key Laboratory of Advanced Textile Composites, Tianjin Polytechnic University, Ministry of Education, Tianjin 300387 (China); School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Xia, Wen; Yang, Ning; Gong, Jixian [Key Laboratory of Advanced Textile Composites, Tianjin Polytechnic University, Ministry of Education, Tianjin 300387 (China); School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Zhang, Jianfei, E-mail: zhangjianfei1960@126.com [Key Laboratory of Advanced Textile Composites, Tianjin Polytechnic University, Ministry of Education, Tianjin 300387 (China); School of Textiles, Tianjin Polytechnic University, Tianjin 300387 (China); Qiao, Changsheng [Key Laboratory of Industrial Microbiology, Tianjin University of Science and Technology, Ministry of Education, Tianjin 300457 (China)

2016-04-01

In this paper, a novel pH-sensitive poly (amino acid) hydrogel based on poly γ-glutamic acid (γ-PGA) and ε-polylysine (ε-PL) was prepared by carbodiimide (EDC) and N-hydroxysuccinimide (NHS) mediated polymerization. The influence of PGA/PL molar ratio and EDC/NHS concentration on the structure and properties was studied. Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) proved that hydrogels were crosslinked through amide bond linkage, and the conversion rate of a carboxyl group could reach 96%. Scanning electron microscopy (SEM) results showed a regularly porous structure with 20 μm pore size in average. The gelation time in the crosslink process of PGA/PL hydrogels was within less than 5 min. PGA/PL hydrogels had excellent optical performance that was evaluated by a novel optotype method. Furthermore, PGA/PL hydrogels were found to be pH-sensitive, which could be adjusted to the pH of swelling media intelligently. The terminal pH of swelling medium could be controlled at 5 ± 1 after equilibrium when the initial pH was within 3–11. The swelling kinetics was found to follow a Voigt model in deionized water but a pseudo-second-order model in normal saline and phosphate buffer solution, respectively. The differential swelling degrees were attributed to the swelling theory based on the different ratio of –COOH/–NH{sub 2} and pore size in hydrogels. The results of mechanical property indicated that PGA/PL hydrogels were soft and elastic. Moreover, PGA/PL hydrogels exhibited excellent biocompatibility by cell proliferation experiment. PGA/PL hydrogels could be degraded in PBS solution and the degradation rate was decreased with the increase of the molar ratio of PL. Considering the simple preparation process and pH-sensitive property, these PGA/PL hydrogels might have high potential for use in medical and clinical fields. - Highlights: • We prepared a biocompatible and degradable poly amino acids hydrogel via EDC

Synthesis of a biocopolymer carrageenan-g-poly(AAm-co-IA/ montmorilonite superabsorbent hydrogel composite

Directory of Open Access Journals (Sweden)

M. Sadeghi

2012-06-01

Full Text Available A novel superabsorbent hydrogel composite based on kappa-carrageenan (κC has been prepared via graft copolymerization of acrylamide (AAm and itaconic acid (IA monomers in the presence of montmorolonite clay powder, methylenebisacrylamide (MBA as the crosslinking agent and ammonium persulfate (APS as initiator. Evidence of grafting and montmorolonite interaction was obtained by comparison of FTIR and TGA spectra of the initial substrates and the superabsorbent composite. A new absorption band at 1722 cm-1 in the composite spectrum confirmed montmorolonite-organic polymer linkages. Moreover, the morphology of the samples was examined by scanning electron microscopy (SEM. The swelling of the superabsorbing hydrogels was also examined in solutions with pH values ranging between 1.0 and 13.0. Finally, the swelling behavior of these composite polymers was investigated in various salt solutions. Results indicated that the swelling capacity decreased with an increase in the ionic strength of the swelling medium. This behavior can be attributed to the charge screening effect of monovalent cations, as well as ionic crosslinking for multivalent cations.

Radiation syntheses of Pectin/acrylamide (PEC/PAM) and Pectin/Diethylaminoethylmethacrylate (PEC/DEAMA) hydrogels as drug delivery systems

International Nuclear Information System (INIS)

Abou El Fadl, F.I.; Maziad, N.A.

2015-01-01

Different pH responsive copolymer hydrogels based on pectin were prepared by the effect of radiation. The physical and chemical properties of prepared hydrogels were studied by FTIR, and TGA. Also, the prepared hydrogels were evaluated for the possible use as drug delivery system for chlortetracycline HCL as model drug. The results revealed that the swelling ratios and the release behavior of hydrogels depend mainly on the pH of the medium and the hydrogel composition. (author)

Reduction of acrylamide formation in potato slices during frying

DEFF Research Database (Denmark)

Pedreschi, Franco; Kaack, K.; Granby, Kit

2004-01-01

and 40 min; 90degreesC for 2 and 9 min); (iii) immersed in citric acid solutions of different concentrations (10 and 20 g/l) for half an hour. Glucose and asparagine concentration was determined in potato slices before frying, whereas acrylamide content was determined in the resultant fried potato chips...... on average 76% and 68% of the glucose and asparagine content compared to the control. Potato slices blanched at 50degreesC for 70 min surprisingly had a very low acrylamide content (28 mum/kg) even when they were fried at 190degreesC. Potato immersion in citric acid solutions of 10 and 20 g/l reduced...

Endoscopic treatment of vesicoureteral reflux with polyacrylate polyalcohol copolymer and dextranomer/hyaluronic acid in adults

Directory of Open Access Journals (Sweden)

Akif Turk

2014-06-01

Full Text Available Purpose Aim of this study is to examine the effectiveness of dextranomer/hyaluronic acid copolymer and polyacrylate polyalcohol copolymer in endoscopic treatment of vesicoureteral reflux disease in adult patients with and without chronic renal failure. Materials and Methods Thirty two patients (12 female, 20 male with a total of 50 renal units were treated for vesicoureteral reflux. There were 26 (81% chronic renal failure patients. The success of treatment was evaluated by voiding cystouretrography at 3rd and 12th months after subureteric injection. The persistence of reflux was considered as failure. Patients were divided into two groups according to injected material. Age, sex, grade of reflux and treatment results were recorded and evaluated. Results Reflux was scored as grade 1 in seven (14%, grade 2 in 16 (32%, grade 3 in 21 (42% and grade 4 in six (12% renal units. There was not patient with grade 5 reflux. Fourteen renal units (28% were treated with dextranomer/hyaluronic acid copolymer (group 1 and 36 renal units (72% were treated with polyacrylate polyalcohol copolymer (group 2. The overall treatment success was achieved at 40 renal units (80%. The treatment was successful at 11 renal units (79% in group 1 and 29 renal units (81% in group 2 (p = 0.71. There was not statistically significant difference between two groups with patients with chronic renal failure in terms of treatment success (p = 1.00. Conclusions The effectiveness of two bulking agents was similar in treatment of vesicoureteral reflux disease in adult patients and patients with chronic renal failure.

Endoscopic treatment of vesicoureteral reflux with polyacrylate polyalcohol copolymer and dextranomer/hyaluronic acid in adults.

Science.gov (United States)

Turk, Akif; Selimoglu, Ahmet; Demir, Kadir; Celik, Osman; Saglam, Erkin; Tarhan, Fatih

2014-01-01

Aim of this study is to examine the effectiveness of dextranomer/hyaluronic acid copolymer and polyacrylate polyalcohol copolymer in endoscopic treatment of vesicoureteral reflux disease in adult patients with and without chronic renal failure. Thirty two patients (12 female, 20 male) with a total of 50 renal units were treated for vesicoureteral reflux. There were 26 (81%) chronic renal failure patients. The success of treatment was evaluated by voiding cystouretrography at 3rd and 12th months after subureteric injection. The persistence of reflux was considered as failure. Patients were divided into two groups according to injected material. Age, sex, grade of reflux and treatment results were recorded and evaluated. Reflux was scored as grade 1 in seven (14%), grade 2 in 16 (32%), grade 3 in 21 (42%) and grade 4 in six (12%) renal units. There was not patient with grade 5 reflux. Fourteen renal units (28%) were treated with dextranomer/hyaluronic acid copolymer (group 1) and 36 renal units (72%) were treated with polyacrylate polyalcohol copolymer (group 2). The overall treatment success was achieved at 40 renal units (80%). The treatment was successful at 11 renal units (79%) in group 1 and 29 renal units (81%) in group 2 (p = 0.71). There was not statistically significant difference between two groups with patients with chronic renal failure in terms of treatment success (p = 1.00). The effectiveness of two bulking agents was similar in treatment of vesicoureteral reflux disease in adult patients and patients with chronic renal failure.

Extraction of silver by gels of sodium poly-acrylic-polyacrylate acid. Application: elimination of chloride anions; Extraction de l'argent par des gels d'acide polyacrylique-polyacrylate de sodium. Application a l'elimination des ions chlorures

Energy Technology Data Exchange (ETDEWEB)

Rifi, E.H. [Universite Ibn-Tofail, Lab. de Synthese Organique et Pocedes d' Extraction, Faculte des Sciences, Kenitra (Morocco); Lakkis, D.; Leroy, J.F.M. [Universite Louis Pasteur, Lab. de Chimie Analytique et Minerale, Ecole Europeenne de Chimie, Polymeres et Materiaux, 67 - Strasbourg (France)

2005-05-01

The extraction of silver from diluted aqueous solutions by gels of sodium poly-acrylic-polyacrylate acid was studied. The study of pH variations shows that the extraction is done by cation-cation exchange process. The highest loading of the gel by silver is obtained at R(moles of Ag{sup +} fixed by the gel/moles of -COO(H, Na))=0.75. The silver gel loaded allows the recovery of ions chlorides from the aqueous solutions. (authors)

A Triblock Copolymer Design Leads to Robust Hybrid Hydrogels for High-Performance Flexible Supercapacitors.

Science.gov (United States)

Zhang, Guangzhao; Chen, Yunhua; Deng, Yonghong; Wang, Chaoyang

2017-10-18

We report here an intriguing hybrid conductive hydrogel as electrode for high-performance flexible supercapacitor. The key is using a rationally designed water-soluble ABA triblock copolymer (termed as IAOAI) containing a central poly(ethylene oxide) block (A) and terminal poly(acrylamide) (PAAm) block with aniline moieties randomly incorporated (B), which was synthesized by reversible additional fragment transfer polymerization. The subsequent copolymerization of aniline monomers with the terminated aniline moieties on the IAOAI polymer generates a three-dimensional cross-linking hybrid network. The hybrid hydrogel electrode demonstrates robust mechanical flexibility, remarkable electrochemical capacitance (919 F/g), and cyclic stability (90% capacitance retention after 1000 cycles). Moreover, the flexible supercapacitor based on this hybrid hydrogel electrode presents a large specific capacitance (187 F/g), superior to most reported conductive hydrogel-based supercapacitors. With the demonstrated additional favorable cyclic stability and excellent capacitive and rate performance, this hybrid hydrogel-based supercapacitor holds great promise for flexible energy-storage device.

Ionizing radiation in the field of hydrogels used for agriculture and medicine

Science.gov (United States)

Radoiu, M.; Martin, D.; Oproiu, C.; Toma, M.; Popescu, A. S.; Bestea, V.; Dragusin, M.; Moraru, R.; Calinescu, I.; Manea, A.

1999-01-01

Some hydrogel types, obtained by gamma ray and electron beam irradiation, such as homopolymers of acrylamide (pAA type), co-polymers of acrylamide and sodium acrylate (pAANA type), homo-polymers of sodium acrylate (pNA type) and homo-polymers of 2-hydroxyethylmethacrylate (pHEMA type), are presented. The effects of the solution's chemical composition, swelling medium nature, radiation absorbed dose and radiation absorbed dose rate upon the swelling degree and mechanical strength of pAA, pAANA, pNA types are discussed. For the pHEMA type, which are reinforced in the polyester network, the studies concerning the influence of the irradiation parameters and chemical composition upon the shape stability after swelling and surface's roughness are also discussed.

Deep frying: the role of water from food being fried and acrylamide formation

Directory of Open Access Journals (Sweden)

Gertz Christian

2003-07-01

Full Text Available The formation of acrylamide during food frying is generally influenced by food type, thermal treatment and equipment. The acrylamide concentration is increased when frying oils containing a higher level of polar materials or silicone or larger amounts of diglycerides. This effect may be caused by moisture escaping from food that has an enhancing effect on the heat transfer. It was noticed that if the moisture in the frying operation was bound by special adsorbents, the acrylamide content could be reduced by more than 50%. The effects of several additives like citric acid on the formation of acrylamide during frying of chips were also investigated. The mechanism of acrylamide formation in fried foods is discussed to explain these findings.

Antioxidant activity and controlled drug delivery potential of tragacanth gum-cl- poly (lactic acid-co-itaconic acid) hydrogel.

Science.gov (United States)

Gupta, Vinod Kumar; Sood, Swadeep; Agarwal, Shilpi; Saini, Adesh K; Pathania, Deepak

2018-02-01

Tragacanth gum-cl-poly (lactic acid-co-itaconic acid) (TG-cl-p(LA-co-IA)) hydrogel is synthesized through graft copolymerization reaction using microwave assisted technique. The synthesized hydrogel was characterised using various analytical and characterization techniques such as FTIR, FESEM, XRD, TGA, TEM and SEM. It was observed that, the maximum percentage swelling (P s ) of the hydrogel was 311.61% after 6h at room temperature and 298.06% after 3h at 60°C and TG-cl-p(LA-co-IA) exhibited highest Amoxicillin loading (73%) in double distilled waterafter 24h. From the controlled release studies, it was evident that maximum drug release of about 96% took place at pH 2.2=after 6h. The synthesized hydrogel also showed mild antioxidant properties and 43.85% of free radical scavenging was occurred at a concentration of 640μg/mL and hence it can be effectively used to reduce the oxidative stresses. In addition to this, the antibacterial studies also showed that it is more effective against S. aureus. Copyright © 2017 Elsevier B.V. All rights reserved.

Hydrogel based QCM aptasensor for detection of avian influenza virus.

Science.gov (United States)

Wang, Ronghui; Li, Yanbin

2013-04-15

The objective of this study was to develop a quartz crystal microbalance (QCM) aptasensor based on ssDNA crosslinked polymeric hydrogel for rapid, sensitive and specific detection of avian influenza virus (AIV) H5N1. A selected aptamer with high affinity and specificity against AIV H5N1 surface protein was used, and hybridization between the aptamer and ssDNA formed the crosslinker in the polymer hydrogel. The aptamer hydrogel was immobilized on the gold surface of QCM sensor using a self-assembled monolayer method. The hydrogel remained in the state of shrink if no H5N1 virus was present in the sample because of the crosslinking between the aptamer and ssDNA in the polymer network. When it exposed to target virus, the binding reaction between the aptamer and H5N1 virus caused the dissolution of the linkage between the aptamer and ssDNA, resulting in the abrupt swelling of the hydrogel. The swollen hydrogel was monitored by the QCM sensor in terms of decreased frequency. Three polymeric hydrogels with different ratio (100:1 hydrogel I, 10:1 hydrogel II, 1:1 hydrogel III) of acrylamide and the aptamer monomer were synthesized, respectively, and then were used as the QCM sensor coating material. The results showed that the developed hydrogel QCM aptasensor was capable of detecting target H5N1 virus, and among the three developed aptamer hydrogels, hydrogel III coated QCM aptasensor achieved the highest sensitivity with the detection limit of 0.0128 HAU (HA unit). The total detection time from sampling to detection was only 30 min. In comparison with the anti-H5 antibody coated QCM immunosensor, the hydrogel QCM aptasensor lowered the detection limit and reduced the detection time. Copyright © 2012 Elsevier B.V. All rights reserved.

Phytoremediation potential of Arabidopsis with reference to acrylamide and microarray analysis of acrylamide-response genes.

Science.gov (United States)

Gao, Jian-Jie; Peng, Ri-He; Zhu, Bo; Wang, Bo; Wang, Li-Juan; Xu, Jing; Sun, Miao; Yao, Quan-Hong

2015-10-01

Acrylamide (ACR) is a widely used industrial chemical. However, it is a dangerous compound because it showed neurotoxic effects in humans and act as reproductive toxicant and carcinogen in many animal species. In the environment, acrylamide has high soil mobility and may travel via groundwater. Phytoremediation is an effective method to remove the environmental pollutants, but the mechanism of plant response to acrylamide remains unknown. With the purpose of assessing remediation potentials of plants for acrylamide, we have examined acrylamide uptake by the model plant Arabidopsis grown on contaminated substrates with high performance liquid chromatography (HPLC) analysis. The result revealed that acrylamide could be absorbed and degraded by Arabidopsis. Further microarray analysis showed that 527 transcripts were up-regulated within 2-days under acrylamide exposure condition. We have found many potential acrylamide-induced genes playing a major role in plant metabolism and phytoremediation. Copyright © 2015 Elsevier Inc. All rights reserved.

Synthesis and characterization of kappaphycus seaweed-poly (acrylic) acid superabsorbent hydrogel for agricultural use

International Nuclear Information System (INIS)

Encinas, Angelica Marie E.

2015-04-01

The main objective of this research is to synthesize and characterize kappaphycus seaweed-poly (acrylic) acid superabsorbent hydrogel for agricultural use. The superabsorbent polymers (SAPs), KCSW: PAA hydrogels were synthesized by using gamma radiation technique from Cobalt-60 source at absorbed dose 0f 5, 10 and 15 kGy. The effect of absorbed dose, seaweed concentration, and concentration of acrylic acid on the degree of swelling was studied and optimum swelling conditions were established. Irradiated samples of 3% KCSW, 50% neutralized AAC at an absorbed dose of 10kGy gave the highest degree of swelling and gel fraction and were found to be suitable for application in the agriculture. Samples with different concentrations of acrylic acid were characterized using FTIR and TGA. The water retention experiment in sandy soil showed high water retention capacity of KCSW: PAA hydrogel at a value of 92% for a period of 7 days. Effect of the germination of mung bean showed very promising result of 78% germination.(author)

Chemically imaging the effects of the addition of nanofibrillated cellulose on the distribution of poly(acrylic acid) in poly(vinyl alcohol)

Science.gov (United States)

Craig Clemons; Julia Sedlmair; Barbara Illman; Rebecca Ibach; Carol Hirschmugl

2013-01-01

The distribution of poly(acrylic acid) (PAA) in model laminates of nanocellulose and poly(vinyl alcohol) (PVOH) was investigated by FTIR chemical imaging. The method was effective in spatially discerning the three components of the composite. PAA can potentially improve the performance of nanocellulose reinforced PVOH by not only crosslinking the PVOH matrix but also...

Electrochemical lithiation performance and characterization of silicon-graphite composites with lithium, sodium, potassium, and ammonium polyacrylate binders.

Science.gov (United States)

Han, Zhen-Ji; Yamagiwa, Kiyofumi; Yabuuchi, Naoaki; Son, Jin-Young; Cui, Yi-Tao; Oji, Hiroshi; Kogure, Akinori; Harada, Takahiro; Ishikawa, Sumihisa; Aoki, Yasuhito; Komaba, Shinichi

2015-02-07

Poly(acrylic acid) (PAH), which is a water soluble polycarboxylic acid, is neutralized by adding different amounts of LiOH, NaOH, KOH, and ammonia (NH4OH) aqueous solutions to fix neutralization degrees. The differently neutralized polyacid, alkali and ammonium polyacrylates are examined as polymeric binders for the preparation of Si-graphite composite electrodes as negative electrodes for Li-ion batteries. The electrode performance of the Si-graphite composite depends on the alkali chemicals and neutralization degree. It is found that 80% NaOH-neutralized polyacrylate binder (a pH value of the resultant aqueous solution is ca. 6.7) is the most efficient binder to enhance the electrochemical lithiation and de-lithiation performance of the Si-graphite composite electrode compared to that of conventional PVdF and the other binders used in this study. The optimum polyacrylate binder highly improves the dispersion of active material in the composite electrode. The binder also provides the strong adhesion, suitable porosity, and hardness for the composite electrode with 10% (m/m) binder content, resulting in better electrochemical reversibility. From these results, the factors of alkali-neutralized polyacrylate binders affecting the electrode performance of Si-graphite composite electrodes are discussed.

Lactic Acid Bacteria Combinations for Wheat Sourdough Preparation and Their Influence on Wheat Bread Quality and Acrylamide Formation.

Science.gov (United States)

Bartkiene, Elena; Bartkevics, Vadims; Krungleviciute, Vita; Pugajeva, Iveta; Zadeike, Daiva; Juodeikiene, Grazina

2017-10-01

Different lactic acid bacteria (LAB) from spontaneous wheat sourdough were isolated, identified, and characterized by their growth, acidification rate, and carbohydrate metabolism. The combinations of isolated LAB (Pediococcus pentosaceus LUHS183 and Leuconostoc mesenteroides LUHS242, P. pentosaceus LUHS183 and Lactobacillus brevis LUHS173, P. pentosaceus LUHS183 and Enterococcus pseudoavium LUHS 234, P. pentosaceus LUHS183 and Lactobacillus curvatus LUHS51, Lactobacillus plantarum LUHS135 and L. curvatus LUHS51, L. plantarum LUHS135 and P. pentosaceus LUHS183) were used for wheat sourdough production, and the effects of LAB fermentation in sourdoughs on wheat bread quality parameters and acrylamide formation were evaluated. All of the tested strains (except E. pseudoavium LUHS 234) were able to ferment l-arabinose, d-ribose, d-galactose, d-fructose, and d-maltose and showed high tolerance to acidic conditions. The highest overall acceptability (135.8 ± 5.5 mm) was found in the bread produced with L. plantarum and P. pentosaceus sourdough. This group of bread also showed the highest shape coefficient (2.59 ± 0.02), the highest specific volume (3.40 ± 0.03 cm 3 /g), the highest porosity (76.6 ± 0.3%), and the highest moisture content (33.7%). Selected sourdoughs reduced acrylamide content in bread samples by 29.5% (sourdough prepared with P. pentosaceus and L. mesenteroides) to 67.2% (sourdough prepared with P. pentosaceus and L. curvatus). These cultures potentially can be used to reduce acrylamide in breads. The data of this study have practical applications. L. plantarum and P. pentosaceus sourdoughs increases overall acceptability, specific volume, and porosity of wheat bread. Besides the fact that sourdoughs produced by using combinations of selected LAB strains improved the quality parameters of bread, fermentation with prepared sourdoughs also reduced the acrylamide content in wheat bread samples by 29.5% (sourdough prepared with P. pentosaceus

Synthesis and Characterization of Crosslinked Hydrogel Polyacrylamide (PAAM)-Co-Alginate Prepared by Gama Irradiation

International Nuclear Information System (INIS)

Erizal; Tita P; Dewi SP

2008-01-01

Crosslinked poly(acrylamide) (PAAM)-co-alginate hydrogels were prepared by gamma irradiation (γ-irradiation) and their conditions such as irradiation dose and alginate concentration were studied. PAAM-co-alginate was crosslinked to yield water sorption materials with various ability to absorb water (swelling) depending on the preparation conditions (e.g. γ-irradiation dosage>20 kGy) and alginate concentration (0.5 - 1 wt %). With an increase of γ-irradiation dosage and alginate concentration, the gels content and water absorption were increasing markedly. The swelling properties of hydrogel in urea and NaCl solution and the effect of temperature were also investigated. Intensity decreasing of functional goups of OH and NH 2 in the IR spectrum indicated that IPN (Interpenetreting Network) structure occured in the network of hydrogels. The ability of hydrogel to absorp and retain a large amount of water suggested their possible uses in health care and agriculture. (author)

Towards a biological monitoring guidance value for acrylamide.

Science.gov (United States)

Sams, C; Jones, K; Warren, N; Cocker, J; Bell, S; Bull, P; Cain, M

2015-08-19

Acrylamide is classified as a potential human carcinogen and neurotoxicant. Biological monitoring is a useful tool for monitoring worker exposure. However, other sources of exposure to acrylamide (including cigarette smoke and diet) also need to be considered. This study has performed repeat measurements of the urinary mercapturic acids of acrylamide (AAMA) and its metabolite glycidamide (GAMA) and determined globin adducts in 20 production-plant workers at a UK acrylamide production facility. The relationship between biomarker levels and environmental monitoring data (air levels and hand washes) was investigated. Good correlations were found between all of the biomarkers (r(2)=0.86-0.91) and moderate correlations were found between the biomarkers and air levels (r(2) = 0.56-0.65). Our data show that urinary AAMA is a reliable biomarker of acrylamide exposure. Occupational hygiene data showed that acrylamide exposure at the company was well within the current UK Workplace Exposure Limit. The 90th percentile of urinary AAMA in non-smoking production-plant workers (537 μmol/mol creatinine (n = 59 samples)) is proposed as a possible biological monitoring guidance value. This 90th percentile increased to 798 μmol/mol if smokers were included (n = 72 samples). These values would be expected following an airborne exposure of less than 0.07 mg/m(3), well below the current UK workplace exposure limit of 0.3mg/m(3). Comparison of biomarker levels in non-occupationally exposed individuals suggests regional variations (between UK and Germany), possibly due to differences in diet. Crown Copyright © 2015. Published by Elsevier Ireland Ltd. All rights reserved.

Comprehensive profiling of mercapturic acid metabolites from dietary acrylamide as short-term exposure biomarkers for evaluation of toxicokinetics in rats and daily internal exposure in humans using isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yu [Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, Zhejiang (China); Zhejiang Key Laboratory for Agro-Food Processing, Zhejiang R & D Center for Food Technology and Equipment, Fuli Institute of Food Science, Zhejiang University, Hangzhou 310058, Zhejiang (China); Wang, Qiao; Cheng, Jun [Department of Food Science and Nutrition, College of Biosystems Engineering and Food Science, Zhejiang University, Hangzhou 310058, Zhejiang (China); Zhang, Jingshun; Xu, Jiaojiao [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang (China); Ren, Yiping, E-mail: renyiping@263.net [Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou 310051, Zhejiang (China)

2015-09-24

Mercapturic acid metabolites from dietary acrylamide are important short-term exposure biomarkers for evaluating the in vivo toxicity of acrylamide. Most of studies have focused on the measurement of two metabolites, N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) and N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA). Thus, the comprehensive profile of acrylamide urinary metabolites cannot be fully understood. We developed an isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of all four mercapturic acid adducts of acrylamide and its primary metabolite glycidamide under the electroscopy ionization negative (ESI-) mode in the present study. The limit of detection (LOD) and limit of quantification (LOQ) of the analytes ranged 0.1–0.3 ng/mL and 0.4–1.0 ng/mL, respectively. The recovery rates with low, intermediate and high spiking levels were calculated as 95.5%–105.4%, 98.2%–114.0% and 92.2%–108.9%, respectively. Acceptable within-laboratory reproducibility (RSD < 7.0%) substantially supported the use of current method for robust analysis. Rapid pretreatment procedures and short run time (8 min per sample) ensured good efficiency of metabolism profiling, indicating a wide application for investigating short-term internal exposure of dietary acrylamide. Our proposed UHPLC-MS/MS method was successfully applied to the toxicokinetic study of acrylamide in rats. Meanwhile, results of human urine analysis indicated that the levels of N-acetyl-S-(2-carbamoylethyl)-L-cysteine-sulfoxide (AAMA-sul), which did not appear in the mercapturic acid metabolites in rodents, were more than the sum of GAMA and N-acetyl-S-(1-carbamoyl-2-hydroxyethyl)-L-cysteine (iso-GAMA). Thus, AAMA-sul may alternatively become a specific biomarker for investigating the acrylamide exposure in humans. Current proposed method provides a substantial methodology support for comprehensive

Comprehensive profiling of mercapturic acid metabolites from dietary acrylamide as short-term exposure biomarkers for evaluation of toxicokinetics in rats and daily internal exposure in humans using isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry

International Nuclear Information System (INIS)

Zhang, Yu; Wang, Qiao; Cheng, Jun; Zhang, Jingshun; Xu, Jiaojiao; Ren, Yiping

2015-01-01

Mercapturic acid metabolites from dietary acrylamide are important short-term exposure biomarkers for evaluating the in vivo toxicity of acrylamide. Most of studies have focused on the measurement of two metabolites, N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) and N-acetyl-S-(2-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA). Thus, the comprehensive profile of acrylamide urinary metabolites cannot be fully understood. We developed an isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of all four mercapturic acid adducts of acrylamide and its primary metabolite glycidamide under the electroscopy ionization negative (ESI-) mode in the present study. The limit of detection (LOD) and limit of quantification (LOQ) of the analytes ranged 0.1–0.3 ng/mL and 0.4–1.0 ng/mL, respectively. The recovery rates with low, intermediate and high spiking levels were calculated as 95.5%–105.4%, 98.2%–114.0% and 92.2%–108.9%, respectively. Acceptable within-laboratory reproducibility (RSD < 7.0%) substantially supported the use of current method for robust analysis. Rapid pretreatment procedures and short run time (8 min per sample) ensured good efficiency of metabolism profiling, indicating a wide application for investigating short-term internal exposure of dietary acrylamide. Our proposed UHPLC-MS/MS method was successfully applied to the toxicokinetic study of acrylamide in rats. Meanwhile, results of human urine analysis indicated that the levels of N-acetyl-S-(2-carbamoylethyl)-L-cysteine-sulfoxide (AAMA-sul), which did not appear in the mercapturic acid metabolites in rodents, were more than the sum of GAMA and N-acetyl-S-(1-carbamoyl-2-hydroxyethyl)-L-cysteine (iso-GAMA). Thus, AAMA-sul may alternatively become a specific biomarker for investigating the acrylamide exposure in humans. Current proposed method provides a substantial methodology support for comprehensive

Fabrication and Evaluation of 2-Hydroxyethyl Methacrylate-co ...

African Journals Online (AJOL)

Purpose: To fabricate and evaluate oral 2-hydroxyethyl methacrylate co-acrylic acid hydrogels as a drug delivery system for sustained release of nicorandil. Methods: HEMA-co-AA hydrogels using different monomer concentrations were prepared by free radical polymerization. N, N-methylene bis acrylamide (MBA) was ...

Ionizing radiation in the field of hydrogels used for agriculture and medicine

International Nuclear Information System (INIS)

Radoiu, M.; Martin, D.; Oproiu, C.; Toma, M.; Popescu, A.S.; Bestea, V.; Dragusin, M.; Moraru, R.; Calinescu, I.; Manea, A.

1999-01-01

Some hydrogel types, obtained by gamma ray and electron beam irradiation, such as homo-polymers of acrylamide (pAA type), co-polymers of acrylamide and sodium acrylate (pAANA type), homo-polymers of sodium acrylate (pNA type) and homo-polymers of 2-hydroxyethylmethacrylate (pHEMA type), are presented. The effects of the solution's chemical composition, swelling medium nature, radiation absorbed dose and radiation absorbed dose rate upon the swelling degree and mechanical strength of pAA, pAANA, pNA types are discussed. For the pHEMA type, which are reinforced in the polyester network, the studies concerning the influence of the irradiation parameters and chemical composition upon the shape stability after swelling and surface's roughness are also discussed. (author)

Synthesis and characterization of chitosan-graft-poly(acrylic acid)/rice husk ash hydrogels composites

International Nuclear Information System (INIS)

Rodrigues, Francisco H.A.; Lopes, Gabriel V.; Pereira, Antonio G.B.; Fajardo, Andre R.; Muniz, Edvani C.

2011-01-01

According to environmental concerns, super absorbent hydrogel composites were synthesized based on rice husk ash (RHA), an industrial waste, and Chitosan-graft-poly(acrylic acid). The WAXS and FTIR data confirmed the syntheses of hydrogel composites. The effect of crystalline or amorphous RHA on water uptake was investigated. It was found that the RHA in crystalline form induces higher water capacity (W eq ) of composites hydrogels due to the fact that the intra-interactions among silanol groups on RHA make available new sites in the polymer matrix, which could interact to water. (author)

The influence of poly(acrylic) acid number average molecular weight and concentration in solution on the compressive fracture strength and modulus of a glass-ionomer restorative.

LENUS (Irish Health Repository)

Dowling, Adam H

2011-06-01

The aim was to investigate the influence of number average molecular weight and concentration of the poly(acrylic) acid (PAA) liquid constituent of a GI restorative on the compressive fracture strength (σ) and modulus (E).

Studies on the Use of Gamma Radiation-Induced for Preparation of Some Modified Resins for the Separation of Some Metal Ions

International Nuclear Information System (INIS)

Abo-Zahra, S.F.

2012-01-01

The work carried out in the present thesis is based on preparation, characterization and applications of some modified resins such as: poly(acrylamide)/poly(maleic acid) P(AAm)/P(MA) interpolymer complex (resin), poly(acrylamide-acrylic acid-amidoxime) P(AAm-AA-AO) resin and poly(hydroxamic acid) P(HA) resin. Poly(acrylamide)/poly(maleic acid) P(AAm)/P(MA) interpolymer complex (resin) was prepared by template polymerization of maleic acid (MA) monomer on poly(acrylamide) P(AAm) hydrogel as a template polymer in the presence of N,N'-methylenebisacrylamide (NMBA) as a crosslinker using gamma radiation-induced technique. Poly(acrylamide-acrylic acid-amidoxime) P(AAm-AA-AO) resin was prepared by template polymerization of acrylic acid (AA) and acrylonitrile (AN) monomers on P(AAm) hydrogel as a template polymer in the presence of NMBA as a crosslinker using gamma radiation-induced technique. The conversion of nitrile group to amidoxime one was carried out by the treatment of the prepared resin with an alkaline solution of hydroxylamine. Poly(hydroxamic acid) P(HA) resin was prepared from the reaction of the corresponding water-soluble P(AAm) previously prepared by gamma radiation-induced with hydroxylamine hydrochloride in an alkaline medium. The functional groups on the prepared polymeric resins were confirmed by using Fourier transform infrared (FTIR) spectra. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) measurements, scanning electron microscopy (SEM) and electron spin resonance (ESR) measurements were performed to evaluate the properties of the prepared polymeric resins, free or complexed with metal ions such as Cu 2+ metal ions.

Irradiation of polyacrylate compositions in air

International Nuclear Information System (INIS)

Wendling, L.A.; Covington, J.B.

1983-01-01

The invention relates to processes for polymerizing polyacrylate functional compositions and in particular to processes for the curing in air of certain polyacrylate functional materials by irradiation

Sorption of zinc by novel pH-sensitive hydrogels based on chitosan, itaconic acid and methacrylic acid

International Nuclear Information System (INIS)

Milosavljevic, Nedeljko B.; Ristic, Mirjana D.; Peric-Grujic, Aleksandra A.; Filipovic, Jovanka M.; Strbac, Svetlana B.; Rakocevic, Zlatko Lj.; Kalagasidis Krusic, Melina T.

2011-01-01

Highlights: → A removal of Zn 2+ ions by pH-sensitive Ch/IA/MAA hydrogel from aqueous solutions was studied. → SEM/EDX analysis and AFM surface topography indicate that sorption takes place on the surface of the hydrogel and in the bulk. → FTIR spectra of the Ch/IA/MAA hydrogel, free and Zn-loaded, indicate that -NH 2 , -OH and -COOH groups are involved in the sorption process. → The negative values of free energy and enthalpy indicated that the adsorption is spontaneous and exothermic one. → The adsorption capacities did not show any significant decrease after the third reuse cycle. - Abstract: Novel pH-sensitive hydrogels based on chitosan, itaconic acid and methacrylic acid were applied as adsorbents for the removal of Zn 2+ ions from aqueous solution. In batch tests, the influence of solution pH, contact time, initial metal ion concentration and temperature was examined. The sorption was found pH dependent, pH 5.5 being the optimum value. The adsorption process was well described by the pseudo-second order kinetic. The hydrogels were characterized by spectral (Fourier transform infrared-FTIR) and structural (SEM/EDX and atomic force microscopy-AFM) analyses. The surface topography changes were observed by atomic force microscopy, while the changes in surface composition were detected using phase imaging AFM. The negative values of free energy and enthalpy indicated that the adsorption is spontaneous and exothermic one. The best fitting isotherms were Langmuir and Redlich-Peterson and it was found that both linear and nonlinear methods were appropriate for obtaining the isotherm parameters. However, the increase of temperature leads to higher adsorption capacity, since swelling degree increased with temperature.

Poly(vinyl alcohol)/poly(acrylic acid)/TiO2/graphene oxide nanocomposite hydrogels for pH-sensitive photocatalytic degradation of organic pollutants

International Nuclear Information System (INIS)

Moon, Young-E; Jung, Gowun; Yun, Jumi; Kim, Hyung-Il

2013-01-01

Graphical abstract: The photocatalytic removal of pollutants was improved by the two-step mechanism based on the adsorption of pollutants by hydrogel and the effective decomposition by combination of TiO 2 and graphene oxide. -- Highlights: • pH sensitive PVA/PAAc hydrogels were prepared by radical polymerization and condensation reaction. • PVA/PAAc/TiO 2 /graphene oxide nanocomposite hydrogels were used for treatment of basic waste water. • Photocatalytic acitivity of TiO 2 was improved by incorporation of graphene oxide. • Photocatalytic decomposition by nanocomposite hydrogel was improved by increasing pH. -- Abstract: Poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels were prepared using radical polymerization and condensation reaction for the photocatalytic treatment of waste water. Graphene oxide was used as an additive to improve the photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 nanocomposite hydrogels. Both TiO 2 and graphene oxide were immobilized in poly(vinyl alcohol)/poly(acrylic acid) hydrogel matrix for an easier recovery after the waste water treatment. The photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels was evaluated on the base of the degradation of pollutants by using UV spectrometer. The improved removal of pollutants was due to the two-step mechanism based on the adsorption of pollutants by nanocomposite hydrogel and the effective decomposition of pollutants by TiO 2 and graphene oxide. The highest swelling of nanocomposite hydrogel was observed at pH 10 indicating that poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels were suitable as a promising system for the treatment of basic waste water

Effect of Sodium Salicylate on the Viscoelastic Properties and Stability of Polyacrylate-Based Hydrogels for Medical Applications

Directory of Open Access Journals (Sweden)

Zuzana Kolarova Raskova

2016-01-01

Full Text Available Investigation was made into the effect exerted by the presence of sodium salicylate (0–2 wt.%, in Carbomer-based hydrogel systems, on processing conditions, rheological and antimicrobial properties in tests against Gram-positive (Staphylococcus aureus and Gram-negative (Escherichia coli bacterial strains, and examples of yeast (Candida albicans and mould (Aspergillus niger. In addition, the work presents an examination of long-term stability by means of aging over one year the given hydrogels at 8°C and 25°C. The results show that 0.5 wt.% NaSal demonstrated a noticeable effect on the hydrogel neutralization process, viscosity, and antimicrobial properties against all of the tested microorganisms. The long-term stability studies revealed that hydrogels can maintain antimicrobial activity as well as viscosity to a degree that would be sufficient for practical use.

Synthesis and characterization of cloisite-30B clay dispersed poly (acryl amide/sodium alginate)/AgNp hydrogel composites for the study of BSA protein drug delivery and antibacterial activity

Science.gov (United States)

Nanjunda Reddy, B. H.; Ranjan Rauta, Pradipta; Venkatalakshimi, V.; Sreenivasa, Swamy

2018-02-01

The aim of this research is to inspect the effect of Cloisite-30B (C30B) modified clay dispersed poly (acrylamide-co-Sodiumalginate)/AgNp hydrogel nanocomposites (PASA/C30B/Ag) for drug delivery and antibacterial activity. A novel hydrogel composite based sodium alginate (SA) and the inorganic modified clay with silver nano particle (C30B/AgNps)polymer hydrogel composites are synthesized via the graft copolymerization of acrylamide (AAm) in an aqueous medium with methylene bisacrylamide (MBA) as a crosslinking agent and ammonium per sulfate(APS) as an initiator. The UV/Visible spectroscopy of obtained composites is successfully studied, which confirms the occurrence of AgNps in the hydrogel composites. And the swelling capacity and bovine serum albumin (BSA) protein as model drug delivery study for these hydrogel nanocomposites have been carried out. The C30B/Ag filled hydrogel composites exhibit superior water absorbency or swelling capacity compared to pure samples and it is establish that the formulations with clay (C30B) dispersed silver nanocomposite hydrogels show improved and somewhat faster rate of drug delivery than other formulations(pure systems) and SEM and TEM reports suggests that the size of AgNps in the composite hydrogels is in the range of 5-10 nm with shrunken surface and the antibacterial characterizations for gram positive and gram negative bacteria are carried out by using Streptococcus faecalis (S. Faecalis) and Escherichia coli (E.coli) as model bacteria and the hydrogel composites of PASA/C30B/Ag shows exceptional antibacterial activity against both the bacteria as compared to pure hydrogel composites samples.

Effect of L-asparaginase on acrylamide mitigation in a fried-dough pastry model.

Science.gov (United States)

Kukurová, Kristína; Morales, Francisco J; Bednáriková, Alena; Ciesarová, Zuzana

2009-12-01

A dough resembling traditional Spanish rosquillas was used as a model to represent classical fried-dough pastry to investigate the effects of asparaginase and heat treatment on amino acid levels and acrylamide mitigation. Wheat-based dough was deep fried at 180 and 200 degrees C for 4, 6, and 8 min. Two recipes were formulated by addition of different asparaginase levels (100 and 500 U/kg flour) to the dough. The temperature/time profile of the frying process, moisture, sugars, amino acids, acrylamide, and some indicators of the Maillard reaction (hydroxymethylfurfural, color, free fluorescence compounds, and browning) were determined to investigate the extent of the reaction and the effect on reactants. At the both levels of asparaginase used, 96-97% of the asparagine present was converted to aspartic acid, and consequently the acrylamide level was very efficiently reduced (up to 90%). The asparaginase also affected the content of glutamine and glutamic acid in dough, resulting in a 37% increase in glutamic acid compared with the untreated sample. Concerning color, browning and Maillard reaction parameters, no significant changes between untreated and enzymatically treated samples were observed, pointing out the potential industrial and domestic enzyme application.

Radiation-induced synthesis of poly(acrylic acid) nanogels

Science.gov (United States)

Matusiak, Malgorzata; Kadlubowski, Slawomir; Ulanski, Piotr

2018-01-01

Nanogel is a two-component system of a diameter in the range of tens of nanometers, consisting of an intramolecularly crosslinked polymer chain and solvent, typically water, filling the space between segments of the macromolecule. Microgels are bigger than nanogels and their size range is between 100 nm to 100 μm. One of the methods used for synthesizing nanogels is linking the segments of a single macromolecule with the use of ionizing radiation, by intramolecular recombination of radiation-generated polymer radicals. The main advantage of this technique is absence of monomers, catalysts, surfactants or crosslinking agents. This method is an interesting alternative way of synthesizing polymeric carriers for biomedical applications. The aim of the study was radiation synthesis and characterization of poly(acrylic acid) - PAA - nanogels and microgels. The physico-chemical properties were described by determination of weight-average molecular weight and dimensions (radius of gyration, hydrodynamic radius) of the nanogels and microgels. Influence of polymer concentration and dose on these parameters was analyzed. Adjusting the PAA concentration and absorbed dose, one can control the molecular weight and dimensions of nanogels. The solutions of PAA were irradiated with two sources of ionizing radiation: γ-source and electron accelerator. The former method yields mainly microgels due to prevailing intermolecular crosslinking, while the latter promotes intramolecular recombination of PAA-derived radicals and in consequence formation of nanogels. In the future radiation-synthesized PAA nanogels, after functionalization, will be tested as carriers for delivering radionuclides to the tumor cells.

Synthesis of Acylated Xylan-Based Magnetic Fe3O4 Hydrogels and Their Application for H2O2 Detection

Directory of Open Access Journals (Sweden)

Qing-Qing Dai

2016-08-01

Full Text Available Acylated xylan-based magnetic Fe3O4 nanocomposite hydrogels (ACX-MNP-gels were prepared by fabricating Fe3O4 nanoctahedra in situ within a hydrogel matrix which was synthesized by the copolymerization of acylated xylan (ACX with acrylamide and N-isopropylacrylamide under ultraviolet irradiation. The size of the Fe3O4 fabricated within the hydrogel matrix could be adjusted through controlling the crosslinking concentrations (C. The magnetic hydrogels showed desirable magnetic and mechanical properties, which were confirmed by XRD, Raman spectroscopy, physical property measurement system, SEM, TGA, and compression test. Moreover, the catalytic performance of the magnetic hydrogels was explored. The magnetic hydrogels (C = 7.5 wt % presented excellent catalytic activity and provided a sensitive response to H2O2 detection even at a concentration level of 5 × 10−6 mol·L−1. This approach to preparing magnetic hydrogels loaded with Fe3O4 nanoparticles endows xylan-based hydrogels with new promising applications in biotechnology and environmental chemistry.

Development of Graft Copolymer Flocculant Based on Acrylamide and Acrylic Acid for the dewatering of coal

International Nuclear Information System (INIS)

Mahmoud, G.A.; Abdel Khalek, M.A

2012-01-01

Most coal preparation processes were carried out in water medium. The water content of coal product has a negative impact on handling and specific energy value. The moisture content may be attributed to the proportion of fine coal, which presents the greatest dewatering problem. A novel polymeric flocculant has been developed by graft copolymerization of acrylamide (AAm) with acrylic acid (AAc) using gamma irradiation technique. The grafted copol621621ymer P(AAm/AAc) was characterized by Fourier-transform infrared spectroscopy (FTIR), and thermo-gravimetric analysis (TGA). The effects of reaction parameters, such as total absorbed dose, and monomer concentration on grafting yield were investigated. The flocculation performance of the graft copolymer P(AAm/AAc) was investigated in coal suspension. It was observed that the grafting ratio was one of the key factors for the flocculating effects. The copolymers with various grafting ratios showed different flocculating properties. It was found that as the grafting ratio increased, the flocculating effect also increased. The flocculation performance of the grafted copolymer was better than that of the commercial flocculant, poly-acrylamide (Magnafloc 1011).

Mechanical properties of poly(N-isopropylacrylamide-Co-itaconic acid) hydrogels

International Nuclear Information System (INIS)

Valderruten, N. E.; Quintana, J. R.; Katime, I.

2001-01-01

It is well known that polymers of N-isopropylacrylamide (NIPA) show lower critical solution temperature (LCST) behavior in water and its gels have a volume phase transition at about 34 degree centigree in water. In this study, we reported the polymerization of NIPA in the presence of N,N methylenebisacrylamide (BIS). Poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide-co-itaconic acid) hydrogels were obtained by swelling the resultant solid xerogels to equilibrium in water. The effects of monomer composition and concentration of added cross-linking agent on the swelling behavior and mechanical properties of these hydrogels at 22 and 37 degree centigree were investigated, the latter involving measurements of shear in a DMTA system. The storage moduli at 22 degree centigree lay within the range 9.08-5.08 KPa. At a fixed BIS concentration, an increase from 22 to 37 degree centigree resulted in an increase in the shear moduli and the effective crosslinking density (v e ) and a decrease in the interaction parameter hydrogel/water, χ. (Author) 6 refs

Acrylamide in processed potato products

Science.gov (United States)

Trace amounts of acrylamide are found in many foods cooked at high temperatures. Acrylamide in processed potato products is formed from reducing sugars and asparagine and is a product of the Maillard reaction. Processed potato products including fries and chips are relatively high in acrylamide comp...

Oil recovery with vinyl sulfonic acid-acrylamide copolymers

Energy Technology Data Exchange (ETDEWEB)

Norton, C.J.; Falk, D.O.

1973-12-18

An aqueous polymer flood containing sulfomethylated alkali metal vinyl sulfonate-acrylamide copolymers was proposed for use in secondary or tertiary enhanced oil recovery. The sulfonate groups on the copolymers sustain the viscosity of the flood in the presence of brine and lime. Injection of the copolymer solution into a waterflooded Berea core, produced 30.5 percent of the residual oil. It is preferred that the copolymers are partially hydrolyzed.

Composite Superabsorbent Hydrogel of Acrylic Copolymer and Eggshell: Effect of Biofiller Addition

OpenAIRE

Queirós, Marcos Vinícius A.; Bezerra, Maslândia N.; Feitosa, Judith P. A.

2017-01-01

Eggshell (ES) is an abundant waste material which is mainly composed of calcium carbonate. A superabsorbent hydrogel composite based on poly(acrylamide-co-potassium acrylate) as matrix containing 17 wt.% of chicken ES powder as a filler was synthesized and compared with the gel without filler. The characterization was carried out by Fourier transform infrared (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), thermogravimetric analysis (TGA), X-ray diffr...

On-line stacking techniques for the nonaqueous capillary electrophoretic determination of acrylamide in processed food

International Nuclear Information System (INIS)

Tezcan, Filiz; Erim, F. Bedia

2008-01-01

In the present study, field amplified sample stacking (FASS) techniques in the nonaqueous capillary electrophoresis method (NACE) were introduced for the on-line concentration of the acrylamide to improve acrylamide detection at 210 nm by diode-array detection. Acetonitrile (ACN) as a nonaqueous solvent permits acrylamide to be protonated through the change of its acid-base chemistry, allowing capillary electrophoretic separation of this compound. Choosing 30 mmol L -1 HClO 4 , 20 mmol L -1 NaClO 4 , 218 mmol L -1 CH 3 COOH in ACN as the separation electrolyte and employing sample stacking methods, the LOD value of acrylamide was decreased to 2.6 ng mL -1 with electrokinetic injection and 4.4 ng mL -1 with hydrodynamic injection. Optimized stacking conditions were applied to the determination of acrylamide in several foodstuffs. The method is simple, rapid, inexpensive, and widely applicable for the determination of acrylamide in food samples

Fabrication and mechanical characterization of graphene oxide-reinforced poly (acrylic acid)/gelatin composite hydrogels

Science.gov (United States)

Faghihi, Shahab; Gheysour, Mahsa; Karimi, Alireza; Salarian, Reza

2014-02-01

Hydrogels have found many practical uses in drug release, wound dressing, and tissue engineering. However, their applications are restricted due to their weak mechanical properties. The role of graphene oxide nanosheets (GONS) as reinforcement agent in poly (acrylic acid) (PAA)/Gelatin (Gel) composite hydrogels is investigated. Composite hydrogels are synthesized by thermal initiated redox polymerization method. Samples are then prepared with 20 and 40 wt. % of PAA, an increasing amount of GONS (0.1, 0.2, and 0.3 wt. %), and a constant amount of Gel. Subsequently, cylindrical hydrogel samples are subjected to a series of compression tests in order to measure their elastic modulus, maximum stress and strain. The results exhibit that the addition of GONS increases the Young's modulus and maximum stress of hydrogels significantly as compared with control (0.0 wt. % GONS). The highest Young's modulus is observed for hydrogel with GO (0.2 wt. %)/PAA (20 wt. %), whereas the highest maximum stress is detected for GO (0.2 wt. %)/PAA (40 wt. %) specimen. The addition of higher amounts of GONS leads to a decrease in the maximum stress of the hydrogel GO (0.3 wt. %)/PAA (40 wt. %). No significant differences are detected for the maximum strain among the hydrogel samples, as the amount of GONS increased. These results suggest that the application of GONS could be used to improve mechanical properties of hydrogel materials. This study may provide an alternative for the fabrication of low-cost graphene/polymer composites with enhanced mechanical properties beneficial for tissue engineering applications.

Study of morphology and mechanical properties of hydrophilic films based on compositions of poly(acrylic acid) and poly(2-hydroxy ethylvinylether)

International Nuclear Information System (INIS)

Bitekenova, A.; Dzhusupbekova, A.; Khutoryanskij, V.; Nurkeeva, Z.

2003-01-01

The hydrophilic films based on compositions of poly(acrylic acid) and poly(2-hydroxy ethylvinylether) were obtained from blend of the corresponding monomers. Radiation crosslinking of composite materials are realize by γ-irradiation method and the gelation doses were calculated. It was shown that mechanical properties of films depend on composition (content of notion component) and conditions of crosslinking. The morphology of polymeric films was investigated by scanning electron microscopy

Acrylamide content in cigarette mainstream smoke and estimation of exposure to acrylamide from tobacco smoke in Poland

Directory of Open Access Journals (Sweden)

Hanna Mojska

2016-07-01

Our results demonstrate that tobacco smoke is a significant source of acrylamide and total exposure to acrylamide in the population of smokers, on average, is higher by more than 50% in comparison with non-smokers. Our estimation of exposure to acrylamide from tobacco smoke is the first estimation taking into account the actual determined acrylamide content in the cigarettes available on the market.

Study of PVC membrane grafted by Acrylic Acid, Acrylonitrile and Acrylamide using preirradiation method

International Nuclear Information System (INIS)

Kattan, M.; Al-Kasseri, H.

2015-03-01

Grafting of acrylic acid, acrylamide and acrylonitrile onto poly vinyl chloride (PVC) films using gamma radiation has been carried out by both type direct and preirradiation methods. The effect of different parameter such as monomer concentration, inhibitor concentration, reaction temperature, reaction time and irradiation dose on the grafting yield were investigated. It was found that the grafting yield depends on these parameters. The grafting yield was strongly monomer dependent and grafting method: the highest was found for AAc by the preirradiation method. The samples were characterized by tensile strength measurement, swilling and ion uptake. The highest increase in swilling was observed on samples grafted with AAc by the preirradiation method.(author)

Rheological and sensory properties of hydrophilic skin protection gels based on polyacrylates.

Science.gov (United States)

Kulawik-Pióro, Agnieszka; Kurpiewska, Joanna; Kułaszka, Agnieszka

2018-03-01

With the current increases in occupational skin diseases, literature data attesting the decreasing efficiency of barrier creams with respect to the manufacturer's declarations and legal regulations granting skin protection gels for employees, research is required to analyse and evaluate the recipes used for hydrophilic skin protection gels based on polyacrylates. This study investigated the rheological properties, pH and sensory perception of hydrophilic barrier gels based on polyacrylates. The acrylic acid derivatives used were good thickeners, and helped to form transparent gels of adequate durability. They could be used to create hydrophilic films on the surface of the skin to protect it against hydrophobic substances. A correlation was shown between the results of the rheological properties and the barrier properties of the gels. This confirms the possibility of monitoring the quality of the gels at the stage of recipe development. Polyacrylates are viable for use in industry to produce hydrophilic barrier creams suitable for skin protection.

Properties and in vitro drug release of hyaluronic acid-hydroxyethyl cellulose hydrogels for transdermal delivery of isoliquiritigenin.

Science.gov (United States)

Kong, Bong Ju; Kim, Ayoung; Park, Soo Nam

2016-08-20

In the present study, the properties of hydrogel systems based on hyaluronic acid (HA)-hydroxyethyl cellulose (HEC) were investigated for effective transdermal delivery of isoliquiritigenin (ILTG). Hydrogels were synthesized by chemical cross-linking, and network structures were characterised using scanning electron microscopy (SEM) and surface area analyser. Texture properties and swelling of HA-HEC hydrogels were found to be closely linked to cross-linker concentration and swelling medium. Water in HA-HEC hydrogels was found to exist mostly in the form of free water. The viscoelasticity and the network stabilization of the hydrogels were analysed via rheological studies. The release kinetics of the hydrogel followed Fickian diffusion mechanism. In an in vitro skin penetration study, the system substantially improved the delivery of ILTG into the skin. These results indicate that the hydrogel system composed of HA and HEC has potential as a transdermal delivery system, with cross-linking density and the swelling medium influencing the properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of acrylamide in coffee and dietary exposure to acrylamide from coffee

DEFF Research Database (Denmark)

Granby, Kit; Fagt, Sisse

2004-01-01

An analytical method for analysing acrylamide in coffee was validated. The analysis of prepared coffee includes a comprehensive clean-up using multimode solid-phase extraction (SPE) by automatic SPE equipment and detection by liquid chromatography tandem mass spectrometry using electrospray...... in the positive mode. The recoveries of acrylamide in ready-to-drink coffee spiked with 5 and 10 mug l(-1) were 96 +/- 14% and 100 +/- 8%, respectively. Within laboratory reproducibility for the same spiking levels were 14% and 9%, respectively. Coffee samples (n = 25) prepared twice by coffee machines and twice...... by a French Press Cafetiere coffee maker contained 8 +/- 3 mug l(-1) and 9 +/- 3 mug l(-1) acrylamide. Five ready-to-drink instant coffee prepared twice contained 8 +/- 2 mug l(-1). Hence, the results do not show significant differences in the acrylamide contents in ready-to-drink coffee prepared by coffee...

Biodegradable hyaluronic acid hydrogels to control release of dexamethasone through aqueous Diels-Alder chemistry for adipose tissue engineering.

Science.gov (United States)

Fan, Ming; Ma, Ye; Zhang, Ziwei; Mao, Jiahui; Tan, Huaping; Hu, Xiaohong

2015-11-01

A robust synthetic strategy of biopolymer-based hydrogels has been developed where hyaluronic acid derivatives reacted through aqueous Diels-Alder chemistry without the involvement of chemical catalysts, allowing for control and sustain release of dexamethasone. To conjugate the hydrogel, furan and maleimide functionalized hyaluronic acid were synthesized, respectively, as well as furan functionalized dexamethasone, for the covalent immobilization. Chemical structure, gelation time, morphologies, swelling kinetics, weight loss, compressive modulus and dexamethasone release of the hydrogel system in PBS at 37°C were studied. The results demonstrated that the aqueous Diels-Alder chemistry provides an extremely selective reaction and proceeds with high efficiency for hydrogel conjugation and covalent immobilization of dexamethasone. Cell culture results showed that the dexamethasone immobilized hydrogel was noncytotoxic and preserved proliferation of entrapped human adipose-derived stem cells. This synthetic approach uniquely allows for the direct fabrication of biologically functionalized gel scaffolds with ideal structures for adipose tissue engineering, which provides a competitive alternative to conventional conjugation techniques such as copper mediated click chemistry. Copyright © 2015. Published by Elsevier B.V.

Radiation Induced Polyvinylpyrrolidone/Polyacrylic Acid Nano-Gel Formation for Biomedical Applications

International Nuclear Information System (INIS)

AbdEl-Rehim, H.; Hegazy, E.A.; Eid, A.; Amr; Ali, A.

2010-01-01

Adopting polyvinylpyrrolidone as template macromolecules and acrylic acid (AA) as monomers, at a concentration ranged from .05 to 1.5%, pH sensitive nano-particle colloids were successfully prepared via template polymerization using gamma radiation in which polymerization of the monomer and self-assembly between the polymer and the template take place simultaneously. The self-assembly was driven by specific interactions between PVP and PAA produced in-situ, leading to PVP/PAAc nano-particles with insoluble inter-polymer complexes. Dynamic light scattering technique was used to indicate size shrinkage and surface charge increase of the PVP/PAAc nano-particles. Many factors affecting the PVP/PAAc nano-particle size such as irradiation dose rate, exposure dose, irradiation temperature and atmosphere, PVP MWt, and feed composition and concentration were investigated. It was found that the reactant feed composition and irradiation temperatures have a great influence on particle size of the prepared nanogel. The structure and morphology of the nano-particles were characterized by FT-IR, UV, viscometry and AFM methods. The structure stability of the nano-particles was studied at different pH solutions. The nano-particles exhibit excellent pH response. When pH changed from acid to base, the particles‘ volume expanded 100 times depending on the irradiation dose at which the nanogel was prepared. The prepared nanogel was loaded with flutamide anticancer drug in the presence of ethanol-water mixture solution and the amount of loaded flutamide was determined. The prepared nano scale polyvinylpyrrolidone/polyacrylic acid bio-polymeric system loaded with flutamide drug is being investigated as anticancer target drug. Also this system will be tested for the treatment of dry-eye-syndrome. (author)

Radiation Induced Polyvinylpyrrolidone/Polyacrylic Acid Nano-Gel Formation for Biomedical Applications

Energy Technology Data Exchange (ETDEWEB)

AbdEl-Rehim, H.; Hegazy, E. A.; Eid, A.; Amr,; Ali, A., E-mail: ha_rehim@hotmail.com [National Centre for Radiation Research, Research Centre (NCRRT), Atomic Energy Authority NCRRT, P.O.Box 29, Nasr City, Cairo (Egypt)

2010-07-01

Adopting polyvinylpyrrolidone as template macromolecules and acrylic acid (AA) as monomers, at a concentration ranged from .05 to 1.5%, pH sensitive nano-particle colloids were successfully prepared via template polymerization using gamma radiation in which polymerization of the monomer and self-assembly between the polymer and the template take place simultaneously. The self-assembly was driven by specific interactions between PVP and PAA produced in-situ, leading to PVP/PAAc nano-particles with insoluble inter-polymer complexes. Dynamic light scattering technique was used to indicate size shrinkage and surface charge increase of the PVP/PAAc nano-particles. Many factors affecting the PVP/PAAc nano-particle size such as irradiation dose rate, exposure dose, irradiation temperature and atmosphere, PVP MWt, and feed composition and concentration were investigated. It was found that the reactant feed composition and irradiation temperatures have a great influence on particle size of the prepared nanogel. The structure and morphology of the nano-particles were characterized by FT-IR, UV, viscometry and AFM methods. The structure stability of the nano-particles was studied at different pH solutions. The nano-particles exhibit excellent pH response. When pH changed from acid to base, the particles‘ volume expanded 100 times depending on the irradiation dose at which the nanogel was prepared. The prepared nanogel was loaded with flutamide anticancer drug in the presence of ethanol-water mixture solution and the amount of loaded flutamide was determined. The prepared nano scale polyvinylpyrrolidone/polyacrylic acid bio-polymeric system loaded with flutamide drug is being investigated as anticancer target drug. Also this system will be tested for the treatment of dry-eye-syndrome. (author)

Co-delivery of evodiamine and rutaecarpine in a microemulsion-based hyaluronic acid hydrogel for enhanced analgesic effects on mouse pain models.

Science.gov (United States)

Zhang, Yong-Tai; Li, Zhe; Zhang, Kai; Zhang, Hong-Yu; He, Ze-Hui; Xia, Qing; Zhao, Ji-Hui; Feng, Nian-Ping

2017-08-07

The aim of this study was to improve the analgesic effect of evodiamine and rutaecarpine, using a microemulsion-based hydrogel (ME-Gel) as the transdermal co-delivery vehicle, and to assess hyaluronic acid as a hydrogel matrix for microemulsion entrapment. A microemulsion was formulated with ethyl oleate as the oil core to improve the solubility of the alkaloids and was loaded into a hyaluronic acid-structured hydrogel. Permeation-enhancing effects of the microemulsion enabled evodiamine and rutaecarpine in ME-Gel to achieve 2.60- and 2.59-fold higher transdermal fluxes compared with hydrogel control (pmicroemulsion exhibited good skin biocompatibility, whereas effective ME-Gel co-delivery of evodiamine and rutaecarpine through the skin enhanced the analgesic effect in mouse pain models compared with hydrogel. Notably, evodiamine and rutaecarpine administered using ME-Gel effectively down-regulated serum levels of prostaglandin E 2 , interleukin 6, and tumor necrosis factor α in formaldehyde-induced mouse pain models, possibly reflecting the improved transdermal permeability of ME-Gel co-delivered evodiamine and rutaecarpine, particularly with hyaluronic acid as the hydrogel matrix. Copyright © 2017 Elsevier B.V. All rights reserved.

Peritoneal adhesion prevention with a biodegradable and injectable N,O-carboxymethyl chitosan-aldehyde hyaluronic acid hydrogel in a rat repeated-injury model

Science.gov (United States)

Song, Linjiang; Li, Ling; He, Tao; Wang, Ning; Yang, Suleixin; Yang, Xi; Zeng, Yan; Zhang, Wenli; Yang, Li; Wu, Qinjie; Gong, Changyang

2016-11-01

Postoperative peritoneal adhesion is one of the serious issues because it induces severe clinical disorders. In this study, we prepared biodegradable and injectable hydrogel composed of N,O-carboxymethyl chitosan (NOCC) and aldehyde hyaluronic acid (AHA), and assessed its anti-adhesion effect in a rigorous and severe recurrent adhesion model which is closer to clinical conditions. The flexible hydrogel, which gelated in 66 seconds at 37 °C, was cross-linked by the schiff base derived from the amino groups of NOCC and aldehyde groups in AHA. In vitro cytotoxicity test showed the hydrogel was non-toxic. In vitro and in vivo degradation examinations demonstrated the biodegradable and biocompatibility properties of the hydrogel. The hydrogel discs could prevent the invasion of fibroblasts, whereas fibroblasts encapsulated in the porous 3-dimensional hydrogels could grow and proliferate well. Furthermore, the hydrogel was applied to evaluate the anti-adhesion efficacy in a more rigorous recurrent adhesion model. Compared with normal saline group and commercial hyaluronic acid (HA) hydrogel, the NOCC-AHA hydrogel exhibited significant reduction of peritoneal adhesion. Compared to control group, the blood and abdominal lavage level of tPA was increased in NOCC-AHA hydrogel group. These findings suggested that NOCC-AHA hydrogel had a great potential to serve as an anti-adhesion candidate.

Hybrid capacitor with activated carbon electrode, Ni(OH) 2 electrode and polymer hydrogel electrolyte

Science.gov (United States)

Nohara, Shinji; Asahina, Toshihide; Wada, Hajime; Furukawa, Naoji; Inoue, Hiroshi; Sugoh, Nozomu; Iwasaki, Hideharu; Iwakura, Chiaki

A new hybrid capacitor (HC) cell was assembled using an activated carbon (AC) negative electrode, an Ni(OH) 2 positive electrode and a polymer hydrogel electrolyte prepared from crosslinked potassium poly(acrylate) (PAAK) and KOH aqueous solution. The HC cell was characterized compared with an electric double layer capacitor (EDLC) using two AC electrodes and the polymer hydrogel electrolyte. It was found that the HC cell successfully worked in the larger voltage range and exhibited ca. 2.4 times higher capacitance than the EDLC cell. High-rate dischargeability of the HC cell was also superior to that of the EDLC cell. These improved characteristics strongly suggest that the HC cell can be a promising system of capacitors with high energy and power densities.

pH-responsive poly(aspartic acid) hydrogel-coated magnetite nanoparticles for biomedical applications.

Science.gov (United States)

Vega-Chacón, Jaime; Arbeláez, María Isabel Amaya; Jorge, Janaina Habib; Marques, Rodrigo Fernando C; Jafelicci, Miguel

2017-08-01

A novel multifunctional nanosystem formed by magnetite nanoparticles coated with pH-responsive poly(aspartic acid) hydrogel was developed. Magnetite nanoparticles (Fe 3 O 4 ) have been intensively investigated for biomedical applications due to their magnetic properties and dimensions similar to the biostructures. Poly(aspartic acid) is a water-soluble, biodegradable and biocompatible polymer, which features makes it a potential candidate for biomedical applications. The nanoparticles surface modification was carried out by crosslinking polysuccinimide on the magnetite nanoparticles surface and hydrolyzing the succinimide units in mild alkaline medium to obtain the magnetic poly(aspartic acid) hydrogel. The surface modification in each step was confirmed by DRIFTS, TEM and zeta potential measurements. The hydrodynamic diameter of the nanosystems decreases as the pH value decreases. The nanosystems showed high colloidal stability in water and no cytotoxicity was detected, which make these nanosystems suitable for biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Polyacrylic acids–bovine serum albumin complexation: Structure and dynamics

International Nuclear Information System (INIS)

Othman, Mohamed; Aschi, Adel; Gharbi, Abdelhafidh

2016-01-01

The study of the mixture of BSA with polyacrylic acids at different masses versus pH allowed highlighting the existence of two regimes of weak and strong complexation. These complexes were studied in diluted regime concentration, by turbidimetry, dynamic light scattering (DLS), zeta-potential measurements and nuclear magnetic resonance (NMR). We have followed the pH effect on the structure and properties of the complex. This allowed refining the interpretation of the phase diagram and understanding the observed phenomena. The NMR measurements allowed probing the dynamics of the constituents versus the pH. The computational method was used to precisely determine the electrostatic potential of BSA and how the polyelectrolyte binds to it at different pH. - Highlights: • Influence of physico-chemical parameters on the electrostatic interactions in the complex system (polyelectrolyte/protein). • Stabilization and encapsulation of biological macromolecules solution by mean of polyelectrolyte. • Properties and structure of mixture obtained by screening the charges of globular protein and at different masses of polyacrylic acids. • Dynamic of the constituents formed by complexes particles. • Evaluation of the electrostatic properties of bovine serum albumin versus pH through solution of the Poisson-Boltzmann equation.

Intestinal transport and metabolism of acrylamide

International Nuclear Information System (INIS)

Zoedl, Bettina; Schmid, Diethart; Wassler, Georg; Gundacker, Claudia; Leibetseder, Valentin; Thalhammer, Theresia; Ekmekcioglu, Cem

2007-01-01

There has been an intensive debate whether dietary exposure to acrylamide could increase the risk of human cancer since the first description of the presence of acrylamide in food in 2002. As the intestinal mechanisms of acrylamide absorption are poorly investigated we studied the transport of acrylamide in differentiated Caco-2 cells and its effects on biotransformation enzymes (CYP2E1 and glutathione S-transferase) and glutathione levels. We found that the apparent permeability of [1- 14 C] acrylamide from the basal to the apical compartment was approximately 20% higher compared to that in the opposite direction. No differences were detected for apical-basal transport against a basal gradient. Transport rates from the apical to the basal chamber at 4 deg. C were about 50% lower than at 37 deg. C. Concentration dependent transport from apical to basal was linear. Predominantly, basal to apical transport was decreased when energy metabolism of the cells was inhibited by application of sodium azide and 2-deoxy-D-glucose. Finally, more acrylamide was transported at luminal pH 6 compared to pH 7.4 from basal to the apical direction. Increasing levels of acrylamide showed no effects on the activity of glutathione S-transferase but resulted in a depletion of total glutathione concentrations. In conclusion transport of acrylamide in the intestine is mediated primarily by passive processes possibly combined with a modest energy- and pH-dependent active secretory component. Depletion of cellular glutathione levels may be one potential mechanism for acrylamide (geno)toxicity

Biocompatible and bioadhesive hydrogels based on 2-hydroxyethyl methacrylate, monofunctional poly(alkylene glycols and itaconic acid

Directory of Open Access Journals (Sweden)

Mićić Maja M.

2007-01-01

Full Text Available New types of hydrogels were prepared by the radical copolymerization of 2-hydroxyethyl methacrylate, itaconic acid and four different poly(alkylene glycol (methacrylate components (Bisomers in a water/ethanol mixture as solvent. The polymers swell in water at 25°C to yield homogeneous transparent hydrogels. All the hydrogels displayed pH sensitive behavior in buffers of the pH range from 2.20 to 7.40, under conditions similar to those of biological fluids. The presence of these two comonomers, which were added to HEMA, increased the swelling degree of the hydrogels and gave gels with better elasticity. The hydrogels were thermally stable in the vicinity of the physiological temperature (37°C. The copolymer containing pure poly(ethylene glycol acrylate units generally had the best properties. The tests performed on the hydrogels confirmed that they were neither hemolytic nor cytotoxic. The copolymer samples showed better cell viability and less hemolytic activity than the PHEMA sample, confirming the assumption that poly(alkylene glycols improve the biocompatibility of hydrogels. Due to their swelling and mechanical characteristics, as well as the very good biocompatibility and bioadhesive properties, poly(Bisomer/HEMA/IA hydrogels are promising for utilization in the field of biomedicals, especially for the controlled release of drugs.

Kinetic model for the formation of acrylamide during the finish-frying of commercial french fries.

Science.gov (United States)

Parker, Jane K; Balagiannis, Dimitrios P; Higley, Jeremy; Smith, Gordon; Wedzicha, Bronislaw L; Mottram, Donald S

2012-09-12

Acrylamide is formed from reducing sugars and asparagine during the preparation of French fries. The commercial preparation of French fries is a multistage process involving the preparation of frozen, par-fried potato strips for distribution to catering outlets, where they are finish-fried. The initial blanching, treatment in glucose solution, and par-frying steps are crucial because they determine the levels of precursors present at the beginning of the finish-frying process. To minimize the quantities of acrylamide in cooked fries, it is important to understand the impact of each stage on the formation of acrylamide. Acrylamide, amino acids, sugars, moisture, fat, and color were monitored at time intervals during the frying of potato strips that had been dipped in various concentrations of glucose and fructose during a typical pretreatment. A mathematical model based on the fundamental chemical reaction pathways of the finish-frying was developed, incorporating moisture and temperature gradients in the fries. This showed the contribution of both glucose and fructose to the generation of acrylamide and accurately predicted the acrylamide content of the final fries.

Interaction between Al3+ and acrylic acid and polyacrylic acid in acidic aqueous solution: a model experiment for the behavior of Al3+ in acidified soil solution.

Science.gov (United States)

Etou, Mayumi; Masaki, Yuka; Tsuji, Yutaka; Saito, Tomoyuki; Bai, Shuqin; Nishida, Ikuko; Okaue, Yoshihiro; Yokoyama, Takushi

2011-01-01

From the viewpoint of the phytotoxicity and mobility of Al(3+) released from soil minerals due to soil acidification, the interaction between Al(3+) and acrylic acid (AA) and polyacrylic acid (PAA) as a model compound of fulvic acid was investigated. The interaction was examined at pH 3 so as to avoid the hydrolysis of Al(3+). The interaction between Al(3+) and AA was weak. However, the interaction between Al(3+) and PAA was strong and depended on the initial (COOH in PAA)/Al molar ratio (R(P)) of the solution. For the range of 1/R(P), the interaction between Al(3+) and PAA can be divided into three categories: (1) 1:1 Al-PAA-complex (an Al(3+) combines to a carboxyl group), (2) intermolecular Al-PAA-complex (an Al(3+) combines to more than 2 carboxyl groups of other Al-PAA-complexes) in addition to the 1:1 Al-PAA-complex and (3) precipitation of intermolecular complexes. In conclusion, R(P) is an important factor affecting the behavior of Al(3+) in acidic soil solution.

Synthesis of poly (acrylamide-co-metacrylic acid) hydrogels By means of gamma irradiation techniques: influence of Absorbed dose on the swelling process

International Nuclear Information System (INIS)

Rapado, Manuel; Altanes, Sonia; Sainz, Dianelys; Prado, Stalina

1999-01-01

In this report gamma radiation techniques were performed a double function of proceeding the processes of polymerization and crosslinking with the advantage of avoid the uses of chemicals crosslinks. The influence of absorbed dose on the swelling ratio as a function of pH have been presented. For these hydrogels, swelling studies indicated that swelling decrease with the increase of the absorbed dose from 10 to 50 kGy. It was confirmed that at the firsts stages (100-150 min) the diffusion studies were in accordance with Fickian behavior and the diffusion coefficients were obtained, whereas the latest stages were in good agreement with second-order diffusion kinetics proposed by Schott 1 .These news hydrogels exhibit a higher degree of swelling, a factor that, a priori, assures high biocompatibility because it increases the similarity with living tissues

Nondispersion flushing fluid based on bentonite containing no more than 15% by weight of clay

Energy Technology Data Exchange (ETDEWEB)

Dorman, J

1977-08-31

A flushing fluid is suggested which prevents dispersion of the drilled rock, facilitates extraction of it mechanically, and thus makes it possible to increase the drilling rate and stability of the well walls. The preparation contains 3-6% of suspended bentonite, 0.01-0.04% of polyacrylamide with molar weight of 0.5-2 million and degree of hydrolysis 0.05-0.35, or copolymer of acrylic acid with acrylamide and 0.01-0.05% polyacrylate or 3-7% potassium chloride. Of the necessary quantity of acrylamide depending on the molecular weight, a 2.0-2.5% aqueous solution is prepared. The solution during intensive mixing is heated to 40-50/sup 0/C, then with constant mixing, a 4-6% aqueous solution of sodium hydroxide is added to it in a quantity needed to reach the degree of hydrolysis 0.05-0.35. This was determined according to preliminary laboratory studies. By using instead of polyacrylamide the copolymer of acrylic acid, acrylamide in a same quantity, of the same molecular weight, and with the same degree of hydrolysis, one can eliminate hydrolysis of sodium hydroxide, and thus simplify the method. In a tank a 3-6% bentonite suspension is prepared and during mixing hydrolyzed polyacrylamide is dosed into it, then polyacrylate. If desired, 3-7% of potassium chloride can be added to the suspension.

Genetic, Physiological, and Environmental Factors Affecting Acrylamide Concentration in Fried Potato Products

Science.gov (United States)

The discovery of acrylamide in processed potato products has brought increased interest in the controlling Maillard reaction precursors (reducing sugars and amino acids) in potato tubers. Because of their effects on nonenzymatic browning of fried potato products, reducing sugars and amino acids have...

Comparison of the mucoadhesive properties of thiolated polyacrylic acid to thiolated polyallylamine.

Science.gov (United States)

Duggan, Sarah; O'Donovan, Orla; Owens, Eleanor; Duggan, Elaine; Hughes, Helen; Cummins, Wayne

2016-02-10

Synthetic polymers, polyacrylic acid (PAA) and polyallylamine (PAAm), were thiolated using different methods of thiolation. Both polymers resulted in comparable thiol contents, thus allowing for the direct comparison of mucoadhesive and cohesive properties between the well-established thiolated PAA and the more novel thiolated PAAm. Thiolation of both polymers improved the swelling ability and the cohesive and mucoadhesive properties in comparison to unmodified control samples. In this study, it was shown that the swelling abilities of the thiolated PAAm sample were far greater than that of the thiolated PAA sample which, in turn, affected the drug release profile of the thiolated PAAm sample. Importantly, however, the mucoadhesive properties of thiolated PAAm were equivalent to that of the thiolated PAA sample as demonstrated by both the adhesion times on porcine intestinal tissue as measured by the rotating cylinder method and by rheological studies with a mucin solution. This study demonstrates the potential thiolated polyallylamine has as a mucoadhesive drug delivery device. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermally reversible hydrogels based on 2-methoxyethylacrylate (MOEA) as drug delivery systems

Energy Technology Data Exchange (ETDEWEB)

Martellini, Flavia; Mei, Lucia Helena [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Engenharia Quimica. Dept. de Polimeros; Moraes, Daniel T.F. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo (Brazil); Balino, Jorge Luis [Centro Atomico Bariloche, RN (Argentina). Inst. Balseiro; Carenza, Mario [Consiglio Nazionale delle Ricerche (CNR), Padova (Italy). Sezione di Lenaro. Ist. di Fotochimica e Radiazioni d' Alta Energia

2000-07-01

Hydrogels of poly(N,N-dimethylacrylamide-co-2-methoxy ethylacrylate) and poly(acrylamide-co-2-methoxy ethylacrylate) have been synthesised by radiation polymerization in dimethylformamide solution with trimethylolpropane trimethacrylate as a cross linker. In this work, it is reported the investigations about the release in vitro of gentamicin sulphate, an antibiotic entrapped in the hydrogels, in aqueous solutions. The result indicate that the release occurs practically in the first 24 h, the release rate is constant over a period of 35 hours and without displaying any significant burst effect. The evidence observed also indicates that the solute transport in the beginning of release is controlled by Fickian diffusion and fractional release of gentamicin is initially linear when plotted against the square root of time, as expected for a Fickian process. (author)

Thermally reversible hydrogels based on 2-methoxyethylacrylate (MOEA) as drug delivery systems

International Nuclear Information System (INIS)

Martellini, Flavia; Mei, Lucia Helena; Balino, Jorge Luis; Carenza, Mario

2000-01-01

Hydrogels of poly(N,N-dimethylacrylamide-co-2-methoxy ethylacrylate) and poly(acrylamide-co-2-methoxy ethylacrylate) have been synthesised by radiation polymerization in dimethylformamide solution with trimethylolpropane trimethacrylate as a cross linker. In this work, it is reported the investigations about the release in vitro of gentamicin sulphate, an antibiotic entrapped in the hydrogels, in aqueous solutions. The result indicate that the release occurs practically in the first 24 h, the release rate is constant over a period of 35 hours and without displaying any significant burst effect. The evidence observed also indicates that the solute transport in the beginning of release is controlled by Fickian diffusion and fractional release of gentamicin is initially linear when plotted against the square root of time, as expected for a Fickian process. (author)

Thiol functionalized polymethacrylic acid-based hydrogel microparticles for oral insulin delivery.

Science.gov (United States)

Sajeesh, S; Vauthier, C; Gueutin, C; Ponchel, G; Sharma, Chandra P

2010-08-01

In the present study thiol functionalized polymethacrylic acid-polyethylene glycol-chitosan (PCP)-based hydrogel microparticles were utilized to develop an oral insulin delivery system. Thiol modification was achieved by grafting cysteine to the activated surface carboxyl groups of PCP hydrogels (Cys-PCP). Swelling and insulin loading/release experiments were conducted on these particles. The ability of these particles to inhibit protease enzymes was evaluated under in vitro experimental conditions. Insulin transport experiments were performed on Caco-2 cell monolayers and excised intestinal tissue with an Ussing chamber set-up. Finally, the efficacy of insulin-loaded particles in reducing the blood glucose level in streptozotocin-induced diabetic rats was investigated. Thiolated hydrogel microparticles showed less swelling and had a lower insulin encapsulation efficiency as compared with unmodified PCP particles. PCP and Cys-PCP microparticles were able to inhibit protease enzymes under in vitro conditions. Thiolation was an effective strategy to improve insulin absorption across Caco-2 cell monolayers, however, the effect was reduced in the experiments using excised rat intestinal tissue. Nevertheless, functionalized microparticles were more effective in eliciting a pharmacological response in diabetic animal, as compared with unmodified PCP microparticles. From these studies thiolation of hydrogel microparticles seems to be a promising approach to improve oral delivery of proteins/peptides. Copyright 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Excited-state dynamics of the medicinal pigment curcumin in a hydrogel.

Science.gov (United States)

Harada, Takaaki; Lincoln, Stephen F; Kee, Tak W

2016-10-12

Curcumin is a yellow polyphenol with multiple medicinal effects. These effects, however, are limited due to its poor aqueous stability and solubility. A hydrogel of 3% octadecyl randomly substituted polyacrylate (PAAC18) has been shown to provide high aqueous stability for curcumin under physiological conditions, offering a route for photodynamic therapy. In this study, the excited-state photophysics of curcumin in the PAAC18 hydrogel is investigated using a combination of femtosecond transient absorption and fluorescence upconversion spectroscopy. The transient absorption results reveal a multiexponential decay in the excited-state kinetics with fast (1 ps & 15 ps) and slow (110 ps & ≈5 ns) components. The fast decay component exhibits a deuterium isotope effect with D 2 O in the hydrogel, indicating that the 15 ps decay component is attributable to excited-state intramolecular hydrogen atom transfer of curcumin in the PAAC18 hydrogel. In addition, solvent reorganisation of excited-state curcumin is investigated using multiwavelength femtosecond fluorescence upconversion spectroscopy. The results show that the dominant solvation response (τ = 0.08 ps) is a fast inertial motion owing to the presence of bulk-like water in the vicinity of the hydrophobic octadecyl substituents of the PAAC18 hydrogel. The results also show an additional response with longer time constants of 1 and 6 ps, which is attributable to translational diffusion of confined water molecules in the three-dimensional, cross-linking network of the octadecyl substituents of PAAC18. Overall, we show that excited-state intramolecular hydrogen atom transfer and solvent reorganisation are major photophysical events for curcumin in the PAAC18 hydrogel.

Dietary acrylamide: What happens during digestion.

Science.gov (United States)

Sansano, M; Heredia, A; Peinado, I; Andrés, A

2017-12-15

Acrylamide is a well-known potentially carcinogen compound formed during thermal processing as an intermediate of Maillard reactions. Three objectives were addressed: the impact of gastric digestion on acrylamide content of French Fries, chips, chicken nuggets, onions rings, breakfast cereals, biscuits, crackers, instant coffee and coffee substitute; the acrylamide content evolution during gastrointestinal digestion of French fries and chips; and the effectiveness of blanching and air-frying on acrylamide mitigation after gastrointestinal digestion. A significant increase (p-value digestion (maximum registered for sweet biscuits, from 30±8 to 150±48µg/kg). However, at the end of the intestinal stage, acrylamide values were statistically similar (p-value=0.132) for French fries and lower than the initial values (before digestion) in potato chips (p-value=0.027). Finally, the low acrylamide content found in blanched and air-fried samples, remained still lower than for deep fried samples even after gastrointestinal digestion. Copyright © 2017 Elsevier Ltd. All rights reserved.

Poly(vinyl alcohol)-Tannic Acid Hydrogels with Excellent Mechanical Properties and Shape Memory Behaviors.

Science.gov (United States)

Chen, Ya-Nan; Peng, Lufang; Liu, Tianqi; Wang, Yaxin; Shi, Shengjie; Wang, Huiliang

2016-10-12

Shape memory hydrogels have promising applications in a wide variety of fields. Here we report the facile fabrication of a novel type of shape memory hydrogels physically cross-linked with both stronger and weaker hydrogen bonding (H-bonding). Strong multiple H-bonding formed between poly(vinyl alcohol) (PVA) and tannic acid (TA) leads to their coagulation when they are physically mixed at an elevated temperature and easy gelation at room temperature. The amorphous structure and strong H-bonding endow the PVA-TA hydrogels with excellent mechanical properties, as indicated by their high tensile strengths (up to 2.88 MPa) and high elongations (up to 1100%). The stronger H-bonding between PVA and TA functions as the "permanent" cross-link and the weaker H-bonding between PVA chains as the "temporary" cross-link. The reversible breakage and formation of the weaker H-bonding imparts the PVA-TA hydrogels with excellent temperature-responsive shape memory. Wet and dried hydrogel samples with a deformed or elongated shape can recover to their original shapes when immersed in 60 °C water in a few seconds or at 125 °C in about 2.5 min, respectively.

Swelling and drug release behavior of poly(2-hydroxyethyl methacrylate/itaconic acid) copolymeric hydrogels obtained by gamma irradiation

International Nuclear Information System (INIS)

Tomic, S.Lj.; Micic, M.M.; Filipovic, J.M.; Suljovrujic, E.H.

2007-01-01

The new copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were prepared by gamma irradiation, in order to examine the potential use of these hydrogels in controlled drug release systems. The influence of IA content in the gel on the swelling characteristics and the releasing behavior of hydrogels, and the effect of different drugs, theophylline (TPH) and fenethylline hydrochloride (FE), on the releasing behavior of P(HEMA/IA) matrix were investigated in vitro. The diffusion exponents for swelling and drug release indicate that the mechanisms of buffer uptake and drug release are governed by Fickian diffusion. The swelling kinetics and, therefore, the release rate depends on the matrix swelling degree. The drug release was faster for copolymeric hydrogels with a higher content of itaconic acid. Furthermore, the drug release for TPH as model drug was faster due to a smaller molecular size and a weaker interaction of the TPH molecules with(in) the P(HEMA/IA) copolymeric networks

Hybrid capacitor with activated carbon electrode, Ni(OH){sub 2} electrode and polymer hydrogel electrolyte

Energy Technology Data Exchange (ETDEWEB)

Nohara, Shinji; Asahina, Toshihide; Wada, Hajime; Furukawa, Naoji; Inoue, Hiroshi; Iwakura, Chiaki [Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan); Sugoh, Nozomu; Iwasaki, Hideharu [Kurashiki Research Laboratory, Kuraray Co., Ltd., 2045-1 Sakazu, Kurashiki, Okayama 710-8691 (Japan)

2006-06-19

A new hybrid capacitor (HC) cell was assembled using an activated carbon (AC) negative electrode, an Ni(OH){sub 2} positive electrode and a polymer hydrogel electrolyte prepared from crosslinked potassium poly(acrylate) (PAAK) and KOH aqueous solution. The HC cell was characterized compared with an electric double layer capacitor (EDLC) using two AC electrodes and the polymer hydrogel electrolyte. It was found that the HC cell successfully worked in the larger voltage range and exhibited ca. 2.4 times higher capacitance than the EDLC cell. High-rate dischargeability of the HC cell was also superior to that of the EDLC cell. These improved characteristics strongly suggest that the HC cell can be a promising system of capacitors with high energy and power densities. (author)

3D Printed, PVA–PAA Hydrogel Loaded-Polycaprolactone Scaffold for the Delivery of Hydrophilic In-Situ Formed Sodium Indomethacin

Directory of Open Access Journals (Sweden)

Mershen Govender

2018-06-01

Full Text Available 3D printed polycaprolactone (PCL-blended scaffolds have been designed, prepared, and evaluated in vitro in this study prior to the incorporation of a polyvinyl alcohol–polyacrylic acid (PVA–PAA hydrogel for the delivery of in situ-formed sodium indomethacin. The prepared PCL–PVA–PAA scaffold is proposed as a potential structural support system for load-bearing tissue damage where inflammation is prevalent. Uniaxial strain testing of the PCL-blended scaffolds were undertaken to determine the scaffold’s resistance to strain in addition to its thermal, structural, and porosimetric properties. The viscoelastic properties of the incorporated PVA–PAA hydrogel has also been determined, as well as the drug release profile of the PCL–PVA–PAA scaffold. Results of these analyses noted the structural strength, thermal stability, and porosimetric properties of the scaffold, as well as the ability of the PCL–PVA–PAA scaffold to deliver sodium indomethacin in simulated physiological conditions of pH and temperature. The results of this study therefore highlight the successful design, fabrication, and in vitro evaluation of a 3D printed polymeric strain-resistant supportive platform for the delivery of sodium indomethacin.

Thiolated polymers: evaluation of their potential as dermoadhesive excipients.

Science.gov (United States)

Grießinger, Julia Anita; Bonengel, Sonja; Partenhauser, Alexandra; Ijaz, Muhammad; Bernkop-Schnürch, Andreas

2017-02-01

The objective of this study was to evaluate and compare four different thiolated polymers regarding their dermoadhesive potential. Therefore, three hydrophilic polymers (poly(acrylic acid), Carbopol 971 and carboxymethylcellulose) and a lipophilic polymer (silicone oil) were chosen to generate thiolated polymers followed by characterization. The total work of adhesion (TWA) and the maximum detachment force (MDF) of formulations containing modified and unmodified polymers were investigated on skin obtained from pig ears using a tensile sandwich technique. The synthesis of thiolated polymers provided 564 µmol, 1079 µmol, 482 µmol and 217 µmol thiol groups per gram poly(acrylic acid), Carbopol 971, carboxymethylcellulose and silicone oil, respectively. Hydrogels containing poly(acrylic acid)-cysteine, Carbopol 971-cysteine, and carboxymethylcellulose-cysteamine exhibited a 6-fold, 25-fold and 9-fold prolonged adhesion on porcine skin than the hydrogel formulations prepared from the corresponding unmodified polymers, respectively. Furthermore, thiolation of silicone oil with thioglycolic acid led to a 5-fold improvement in adhesion compared to the unmodified silicone oil. A comparison between the four thiolated polymer formulations showed a clear correlation between the amount of coupled thiol groups and the TWA. According to these results thiomers might also be useful excipients to provide a prolonged dermal resistance time of various formulations.

Elastin-like protein-hyaluronic acid (ELP-HA) hydrogels with decoupled mechanical and biochemical cues for cartilage regeneration.

Science.gov (United States)

Zhu, Danqing; Wang, Huiyuan; Trinh, Pavin; Heilshorn, Sarah C; Yang, Fan

2017-05-01

Hyaluronic acid (HA) is a major component of cartilage extracellular matrix and is an attractive material for use as 3D injectable matrices for cartilage regeneration. While previous studies have shown the promise of HA-based hydrogels to support cell-based cartilage formation, varying HA concentration generally led to simultaneous changes in both biochemical cues and stiffness. How cells respond to the change of biochemical content of HA remains largely unknown. Here we report an adaptable elastin-like protein-hyaluronic acid (ELP-HA) hydrogel platform using dynamic covalent chemistry, which allows variation of HA concentration without affecting matrix stiffness. ELP-HA hydrogels were created through dynamic hydrazone bonds via the reaction between hydrazine-modified ELP (ELP-HYD) and aldehyde-modified HA (HA-ALD). By tuning the stoichiometric ratio of aldehyde groups to hydrazine groups while maintaining ELP-HYD concentration constant, hydrogels with variable HA concentration (1.5%, 3%, or 5%) (w/v) were fabricated with comparable stiffness. To evaluate the effects of HA concentration on cell-based cartilage regeneration, chondrocytes were encapsulated within ELP-HA hydrogels with varying HA concentration. Increasing HA concentration led to a dose-dependent increase in cartilage-marker gene expression and enhanced sGAG deposition while minimizing undesirable fibrocartilage phenotype. The use of adaptable protein hydrogels formed via dynamic covalent chemistry may be broadly applicable as 3D scaffolds with decoupled niche properties to guide other desirable cell fates and tissue repair. Copyright © 2017 Elsevier Ltd. All rights reserved.

Isolation and characterization of an acrylamide-degrading yeast Rhodotorula sp. strain MBH23 KCTC 11960BP.

Science.gov (United States)

Rahim, M B H; Syed, M A; Shukor, M Y

2012-10-01

As well as for chemical and environmental reasons, acrylamide is widely used in many industrial applications. Due to its carcinogenicity and toxicity, its discharge into the environment causes adverse effects on humans and ecology alike. In this study, a novel acrylamide-degrading yeast has been isolated. The isolate was identified as Rhodotorula sp. strain MBH23 using ITS rRNA analysis. The results showed that the best carbon source for growth was glucose at 1.0% (w/v). The optimum acrylamide concentration, being a nitrogen source for cellular growth, was at 500 mg l(-1). The highest tolerable concentration of acrylamide was 1500 mg l(-1) whereas growth was completely inhibited at 2000 mg l(-1). At 500 mg l(-1), the strain MBH completely degraded acrylamide on day 5. Acrylic acid as a metabolite was detected in the media. Strain MBH23 grew well between pH 6.0 and 8.0 and between 27 and 30 °C. Amides such as 2-chloroacetamide, methacrylamide, nicotinamide, acrylamide, acetamide, and propionamide supported growth. Toxic heavy metals such as mercury, chromium, and cadmium inhibited growth on acrylamide. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controlled in situ formation of polyacrylamide hydrogel on PET surface via SI-ARGET-ATRP for wound dressings

Energy Technology Data Exchange (ETDEWEB)

Nazari Pour, Sedigheh [Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Ghugare, Shivkumar V. [Department of Textile Science, Faculty of Human Ecology, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Wiens, Richard; Gough, Kathleen [Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Liu, Song, E-mail: Song.Liu@umanitoba.ca [Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Department of Textile Science, Faculty of Human Ecology, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada); Department of Biosystems Engineering, Faculty of Engineering, University of Manitoba, Winnipeg, Canada R3T 2N2 (Canada)

2015-09-15

Graphical abstract: - Highlights: • We grow poly(acrylamide) (PAM) hydrgol from a polymer surface in a controlled way. • Divinyl crosslinker doesn't compromise the control chain growth feature of ARGET-ATRP. • ATR-FTIR-FPA images (spatial resolution 220 nm) reveal a uniform grafting of PAM. • PAM grafted wound dressing can be dual functional: low-adherent and antibacterial. - Abstract: Well-defined polyacrylamide (PAM) hydrogel was synthesized on the surface of poly(ethylene terephthalate) (PET) film via surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET-ATRP). Following the deposition of an ATRP initiator (2-bromoisobutyrylbromide) on PET film, PAM hydrogel was grafted from the functionalized PET surface via ARGET-ATRP. XPS and FTIR-ATR confirmed that PAM hydrogel was successfully grafted on the PET surface. Results from AFM, SEM, and FTIR-FPA microscopic investigations showed that PAM hydrogel uniformly covers the surface of PET film. The grafting yield increases linearly with increasing reaction time, indicating that the growth of PAM hydrogel on the surface of PET is well controlled. In a cell adhesion assay, PAM hydrogel grafted PET films (PAM hydrogel-g-PET) showed low adhesion to keratinocyte cells. To impart PAM hydrogel-g-PET with antibacterial function, AgNPs were self-assembled along the amide side chains of PAM hydrogel. AgNPs loaded-PAM hydrogel-g-PET shows 99% reduction in the number of multidrug-resistant Pseudomonas aeruginosa within 3 h contact.

Controlled in situ formation of polyacrylamide hydrogel on PET surface via SI-ARGET-ATRP for wound dressings

International Nuclear Information System (INIS)

Nazari Pour, Sedigheh; Ghugare, Shivkumar V.; Wiens, Richard; Gough, Kathleen; Liu, Song

2015-01-01

Graphical abstract: - Highlights: • We grow poly(acrylamide) (PAM) hydrgol from a polymer surface in a controlled way. • Divinyl crosslinker doesn't compromise the control chain growth feature of ARGET-ATRP. • ATR-FTIR-FPA images (spatial resolution 220 nm) reveal a uniform grafting of PAM. • PAM grafted wound dressing can be dual functional: low-adherent and antibacterial. - Abstract: Well-defined polyacrylamide (PAM) hydrogel was synthesized on the surface of poly(ethylene terephthalate) (PET) film via surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET-ATRP). Following the deposition of an ATRP initiator (2-bromoisobutyrylbromide) on PET film, PAM hydrogel was grafted from the functionalized PET surface via ARGET-ATRP. XPS and FTIR-ATR confirmed that PAM hydrogel was successfully grafted on the PET surface. Results from AFM, SEM, and FTIR-FPA microscopic investigations showed that PAM hydrogel uniformly covers the surface of PET film. The grafting yield increases linearly with increasing reaction time, indicating that the growth of PAM hydrogel on the surface of PET is well controlled. In a cell adhesion assay, PAM hydrogel grafted PET films (PAM hydrogel-g-PET) showed low adhesion to keratinocyte cells. To impart PAM hydrogel-g-PET with antibacterial function, AgNPs were self-assembled along the amide side chains of PAM hydrogel. AgNPs loaded-PAM hydrogel-g-PET shows 99% reduction in the number of multidrug-resistant Pseudomonas aeruginosa within 3 h contact

Direct laser writing of synthetic poly(amino acid) hydrogels and poly(ethylene glycol) diacrylates by two-photon polymerization

Energy Technology Data Exchange (ETDEWEB)

Käpylä, Elli, E-mail: elli.kapyla@tut.fi [Department of Electronics and Communications Engineering, Tampere University of Technology, P.O. Box 692, 33101 Tampere (Finland); BioMediTech, Biokatu 10, 33520 Tampere (Finland); Sedlačík, Tomáš [Institute of Macromolecular Chemistry of the Academy of Sciences of the Czech Republic, Heyrovského nám. 2, 162 06 Praha 6, Břevnov, Prague (Czech Republic); Aydogan, Dogu Baran [Department of Electronics and Communications Engineering, Tampere University of Technology, P.O. Box 692, 33101 Tampere (Finland); BioMediTech, Biokatu 10, 33520 Tampere (Finland); Viitanen, Jouko [VTT Technical Research Centre of Finland, P.O. Box 1300, 33101 Tampere (Finland); Rypáček, František [Institute of Macromolecular Chemistry of the Academy of Sciences of the Czech Republic, Heyrovského nám. 2, 162 06 Praha 6, Břevnov, Prague (Czech Republic); Kellomäki, Minna [Department of Electronics and Communications Engineering, Tampere University of Technology, P.O. Box 692, 33101 Tampere (Finland); BioMediTech, Biokatu 10, 33520 Tampere (Finland)

2014-10-01

The additive manufacturing technique of direct laser writing by two-photon polymerization (2PP-DLW) enables the fabrication of three-dimensional microstructures with superior accuracy and flexibility. When combined with biomimetic hydrogel materials, 2PP-DLW can be used to recreate the microarchitectures of the extracellular matrix. However, there are currently only a limited number of hydrogels applicable for 2PP-DLW. In order to widen the selection of synthetic biodegradable hydrogels, in this work we studied the 2PP-DLW of methacryloylated and acryloylated poly(α-amino acid)s (poly(AA)s). The performance of these materials was compared to widely used poly(ethylene glycol) diacrylates (PEGdas) in terms of polymerization and damage thresholds, voxel size, line width, post-polymerization swelling and deformation. We found that both methacryloylated and acryloylated poly(AA) hydrogels are suitable to 2PP-DLW with a wider processing window than PEGdas. The poly(AA) with the highest degree of acryloylation showed the greatest potential for 3D microfabrication. - Highlights: • Methacryloylated and acryloylated poly(α-amino acid)s (poly(AA)s) were synthesized. • Direct laser writing by two-photon polymerization (2PP-DLW) of poly(AA)s is shown. • Poly(AA)s have wider processing windows than poly(ethylene glycol) diacrylates. • 3D poly(AA) structures with 80% water content were fabricated.

Direct laser writing of synthetic poly(amino acid) hydrogels and poly(ethylene glycol) diacrylates by two-photon polymerization

International Nuclear Information System (INIS)

Käpylä, Elli; Sedlačík, Tomáš; Aydogan, Dogu Baran; Viitanen, Jouko; Rypáček, František; Kellomäki, Minna

2014-01-01

The additive manufacturing technique of direct laser writing by two-photon polymerization (2PP-DLW) enables the fabrication of three-dimensional microstructures with superior accuracy and flexibility. When combined with biomimetic hydrogel materials, 2PP-DLW can be used to recreate the microarchitectures of the extracellular matrix. However, there are currently only a limited number of hydrogels applicable for 2PP-DLW. In order to widen the selection of synthetic biodegradable hydrogels, in this work we studied the 2PP-DLW of methacryloylated and acryloylated poly(α-amino acid)s (poly(AA)s). The performance of these materials was compared to widely used poly(ethylene glycol) diacrylates (PEGdas) in terms of polymerization and damage thresholds, voxel size, line width, post-polymerization swelling and deformation. We found that both methacryloylated and acryloylated poly(AA) hydrogels are suitable to 2PP-DLW with a wider processing window than PEGdas. The poly(AA) with the highest degree of acryloylation showed the greatest potential for 3D microfabrication. - Highlights: • Methacryloylated and acryloylated poly(α-amino acid)s (poly(AA)s) were synthesized. • Direct laser writing by two-photon polymerization (2PP-DLW) of poly(AA)s is shown. • Poly(AA)s have wider processing windows than poly(ethylene glycol) diacrylates. • 3D poly(AA) structures with 80% water content were fabricated

Investigation on a hydrogel based passive thermal management system for lithium ion batteries

International Nuclear Information System (INIS)

Zhang, Sijie; Zhao, Rui; Liu, Jie; Gu, Junjie

2014-01-01

An appropriate operating temperature range is critical for the overall performance and safety of lithium-ion batteries. Considering the excellent performance of water in heat dissipation in industrial applications, in this paper, a water based PAAS (sodium polyacrylate) hydrogel thermal management system has been proposed to handle the heat surge during the operation of a Li-ion battery pack. A thermal model with constant heat generation rate is employed to simulate the high current discharge process (i.e., 10 A) on a 4S1P battery pack, which shows a good consistence with the corresponding experimental results. Further experiments on 4S1P and 5S1P battery packs validate the effectiveness of the hydrogel thermal management system in lowering the temperature increase rate of battery packs at different discharge rates and minimizing the temperature difference inside battery packs during operation, thereby enhancing the stability and safety in continuous charge and discharge process and decreasing the capacity fading rate during life cycle tests. This novel hydrogel based cooling system also possesses the characteristics of high energy efficiency, easy manufacturing process, compactness, and low cost. - Highlights: • A hydrogel thermal management system (TMS) is proposed for Li-ion battery. • It is found that the heat from internal resistance predominates at high discharge rate. • Effectiveness of hydrogel in controlling cell temperature is proved. • Battery equipped with hydrogel TMS is safer at continuous high rate cycle test. • The capacity fading rate of battery pack decreases when hydrogel TMS is implemented

Radiation Synthesis and Characterization of Polyvinyl alcohol/Acrylic acid Hydrogel and its Amoxicillin drug Delivery application

International Nuclear Information System (INIS)

El kelesh, N.A.; Ismail, S.A.; Abd El Wahab, S.Y.

2012-01-01

Polyvinyl alcohol /Acrylic acid based hydrogels can be synthesized by Gamma radiation technique using 60 Co irradiation cell at irradiation dose rate 1.8 Gray/second. The optimum conditions of hydrogel preparation takes place at different factors such as composition ratios of PVA/AAc, different comonomer concentration and different irradiation doses resulting in hydrogel with maximum gel percent as it obtained 98%. The structures of hydrogels were characterized by FTIR analysis. The results can be confirmed the expected structures as well as free radical copolymerization. According to the swelling studies, hydrogels with high content of AAc gave relatively high swelling percent. The hydrogel showed a super adsorbent with swelling capacity 10320 %. Water diffusion into such prepared hydrogel showed a non-Fickian type where a Fickian number was 0.77. This hydrogel was used for the adsorption of amoxicillin drug from their aqueous solutions. The factors affected on the uptake conditions such as ph, time and initial feed concentration on the amoxicillin adsorption capacity of hydrogel was studied depending on Freundlish model of adsorption isotherm.. It was observed that the interaction between drug and ionic comonomers was enhanced in alkaline medium and high initial feed concentration of the drug. The ability of the hydrogel and the affinity of the drug to be adsorbed can be cleared by determining the empirical constants n and k respectively from the logarithmic form of Freundlish equation. The recovery of drug was also investigated in different ph values to study the suitable condition of drug release as drug delivery system.

Depletion of abundant plasma proteins by poly(N-isopropylacrylamide-acrylic acid) hydrogel particles

DEFF Research Database (Denmark)

Such-Sanmartín, Gerard; Ventura-Espejo, Estela; Jensen, Ole N

2014-01-01

the application of pH-sensitive poly(N-isopropylacrylamide-acrylic acid) hydrogel particles for removal of abundant plasma proteins, prior to proteome analysis by MS. Protein depletion occurs by two separate mechanisms: (1) hydrogel particles incubated with low concentrations of plasma capture abundant proteins...... proteins are released and recovered in the eluate. We developed a series of distinct depletion protocols that proved useful for sample depletion and fractionation and facilitated targeted analysis of putative biomarkers such as IGF1-2, IBP2-7, ALS, KLK6-7, ISK5, and PLF4 by selected reaction monitoring...

Laser-ignited frontal polymerization of shape-controllable poly(VI-co-AM) hydrogels based on 3D templates toward adsorption of heavy metal ions

Science.gov (United States)

Fan, Suzhen; Liu, Sisi; Wang, Xiao-Qiao; Wang, Cai-Feng; Chen, Su

2016-06-01

Given the increasing heavy metal pollution issue, fast preparation of polymeric hydrogels with excellent adsorption property toward heavy metal ions is very attractive. In this work, a series of poly( N-vinylimidazole-co-acrylamide) (poly(VI-co-AM)) hydrogels were synthesized via laser-ignited frontal polymerization (LIFP) for the first time. The dependence of frontal velocity and temperature on two factors monomer ratios and initiator concentrations was systematically investigated. Poly(VI-co-AM) hydrogels with any self-supporting shapes can be synthesized by a one-step LIFP in seconds through the application of 3D templates. These shape-persistent hydrogels are pH-responsive and exhibit excellent adsorption/desorption characteristics toward Mn(II), Zn(II), Cd(II), Ni(II), Cu(II) and Co(II) ions, and the adsorption conformed to the pseudo-second-order kinetic model. The reusability of the hydrogels toward mental ions adsorption was further researched, which suggested that the hydrogels can be reused without serious decrease in adsorption capacity. This work might open a promising strategy to facilely prepare shape-controllable hydrogels and expand the application of LIFP.

Preparation, properties and biological application of pH-sensitive poly(ethylene oxide) (PEO) hydrogels grafted with acrylic acid(AAc) using gamma-ray irradiation

International Nuclear Information System (INIS)

Nho, Y.C.; Mook Lim, Youn; Moo Lee, Young

2004-01-01

pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. In this study, hydrogels based on poly(ethylene oxide) (PEO) networks grafted with acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by γ-ray irradiation, and then grafting by AAc monomer onto the PEO hydrogels with the subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydrogels were used as a carrier for the drug delivery systems for the controlled release of insulin. The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/VIS spectrophotometer. Insulin was loaded into freeze-dried hydrogels (7 mmx3 mmx2.5 mm) and administrated orally to healthy and diabetic Wistar rats. The oral administration of insulin-loaded hydrogels to Wistar rats decreased the blood glucose levels obviously for at least 4 h due to the absorption of insulin in the gastrointestinal tract

Toxicity of acrylamide and its metabolite – Glicydamide

Directory of Open Access Journals (Sweden)

Daria Pingot

2013-04-01

Full Text Available Acrylamide is a synthetic chemical compound commonly used in many branches of industry. It is mainly used in the synthesis of polyacrylamides, which are widely employed in plastics, paints, varnishes, adhesives and mortars production. Acrylamide is also applied in the cellulose-paper and cosmetic industries to produce toiletries and cosmetics. The interest in acrylamide increased in 2002, when Swedish scientists showed that a considerable amount of this substance is formed during frying and baking of various foods. Studies concerning toxicity of acrylamide and its metabolite - glicydamide showed their neurotoxic, genotoxic and carcinogenic effects. Neverthless, in humans only neurotoxic effect of acrylamide has been clearly evidenced. Genotoxic nature of acetylamide manifests itself mainly in its metabolic conversion to the epoxide derivative glicydamide. Carcinogenic effects of acrylamide have been shown in animal studies. Epidemiological studies have not provided explicit evidence that acrylamide supplied with the diet can initiate the formation of tumors in humans. Acrylamide exposure is assessed by measuring specific compounds (adducts formed during the reaction of acrylamide with hemoglobin and DNA. Med Pr 2013;64(2:259–271

Swelling and thermodynamic studies of temperature responsive 2-hydroxyethyl methacrylate/itaconic acid copolymeric hydrogels prepared via gamma radiation

International Nuclear Information System (INIS)

Tomic, Simonida L.J.; Micic, Maja M.; Filipovic, Jovanka M.; Suljovrujic, Edin H.

2007-01-01

The copolymeric hydrogels based on 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA) were synthesized by gamma radiation induced radical polymerization. Swelling and thermodynamic properties of PHEMA and copolymeric P(HEMA/IA) hydrogels with different IA contents (2, 3.5 and 5 mol%) were studied in a wide pH and temperature range. Initial studies of so-prepared hydrogels show interesting pH and temperature sensitivity in swelling and drug release behavior. Special attention was devoted to temperature investigations around physiological temperature (37 deg. C), where small changes in temperature significantly influence swelling and drug release of these hydrogels. Due to maximum swelling of hydrogels around 40 deg. C, the P(HEMA/IA) hydrogel containing 5 mol% of IA without and with drug-antibiotic (gentamicin) were investigated at pH 7.40 and in the temperature range 25-42 deg. C, in order to evaluate their potential for medical applications

Acrylamide: inhibition of formation in processed food and mitigation of toxicity in cells, animals, and humans.

Science.gov (United States)

Friedman, Mendel

2015-06-01

Potentially toxic acrylamide is largely derived from the heat-inducing reactions between the amino group of the amino acid asparagine and carbonyl groups of glucose and fructose in plant-derived foods including cereals, coffees, almonds, olives, potatoes, and sweet potatoes. This review surveys and consolidates the following dietary aspects of acrylamide: distribution in food, exposure and consumption by diverse populations, reduction of the content in different food categories, and mitigation of adverse in vivo effects. Methods to reduce acrylamide levels include selecting commercial food with a low acrylamide content, selecting cereal and potato varieties with low levels of asparagine and reducing sugars, selecting processing conditions that minimize acrylamide formation, adding food-compatible compounds and plant extracts to food formulations before processing that inhibit acrylamide formation during processing of cereal products, coffees, teas, olives, almonds, and potato products, and reducing multiorgan toxicity (antifertility, carcinogenicity, neurotoxicity, teratogenicity). The herein described observations and recommendations are of scientific interest for food chemistry, pharmacology, and toxicology, but also have the potential to benefit nutrition, food safety, and human health.

Fabrication of hydrogels with elasticity changed by alkaline phosphatase for stem cell culture.

Science.gov (United States)

Toda, Hiroyuki; Yamamoto, Masaya; Uyama, Hiroshi; Tabata, Yasuhiko

2016-01-01

The objective of this study is to design hydrogels whose elasticity can be changed by alkaline phosphatase (ALP) in cell culture and evaluate the effect of hydrogel elasticity on an osteogenic gene expression of cells. Hydrogels were prepared by the radical polymerization of acrylamide (AAm), N,N'-methylenebisacrylamide (BIS), and Phosmer™M containing phosphate groups (PE-PAAm hydrogels). The storage modulus of PE-PAAm hydrogels prepared was changed by the preparation conditions. When human mesenchymal stem cells (hMSC) were cultured on the ALP-responsive PE-PAAm hydrogels in the presence or absence of ALP, the morphology of hMSC was observed and one of the osteogenic differentiation markers, Runx2, was evaluated. By ALP addition into the culture medium, the morphology of hMSC was changed into an elongated shape without cell damage. ALP addition modified the level of Runx2 gene expression, which was influenced by the modulus of PE-PAAm hydrogels. It is concluded that the elasticity change of hydrogel substrates in cell culture had an influence on the Runx2 gene expression of hMSC. Stem cells sense the surface elasticity of culture substrates, and their differentiation fate is biologically modified by substrate properties. Most of experiments have been performed in static conditions during cell culture, while the in vivo microenvironment is dynamically changed. In this study, we established to design an enzyme-responsive hydrogel whose elasticity can be changed by alkaline phosphatase (ALP) in cell culture to mimic in vivo conditions. As a result, the cells were deformed and the gene expression level of an osteogenic maker, Runx2, was modified by ALP treatment. This is the novel report describing to demonstrate that the dynamic alteration of hydrogel substrate elasticity could modulate the osteoblastic gene expression of human MSC in vitro. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Radiation preparation of drug carriers based on poly(N-isopropylacrylamide) hydrogels, their loading capacities and controlled release rates for dexamethasone and tegafur

International Nuclear Information System (INIS)

Hoang Dang Sang; Nguyen Van Binh; Tran Bang Diep; Nguyen Thi Thom; Hoang Phuong Thao; Pham Duy Duong; Tran Minh Quynh

2015-01-01

Thermo-sensitive hydrogels have great potential in some applications. In order to use as the drug delivery systems, the hydrogels should be biocompatibility. New polymers with more biocompatibility and better biodegradability, and environmental friendly crosslinking agents would be necessary for the successful drug carriers. Poly (N-isopropylacrylamide-co-dimethylacrylamide) based hydrogels have been prepared from the admixture solutions of N-isopropylacrylamide (NIPA) and N,N’-dimethyl acrylamide (DMA) by radiation copolymerization and crosslinking at radiation dose of 20 kGy as reported in our previous study. Water swelling behaviour of the resulting hydrogels were much depended on their nature such as initial ratio of NIPA and DMA. The drug-loaded hydrogels were prepared by merging hydrogel in the solutions containing corresponding drugs. Loading capacity of the hydrogels were about 48.6 and 95.7 mg per g dried hydrogel for dexamethasone and tegafur. The release studies showed that the presence of ions in simulated body fluid and temperature of the solution much affecting to in vitro release behaviors of hydrogels for dexamethasone and tegafur. The release rates were fast for both drug models. The result also revealed that these drug carriers were biocompatibility without skin irritation, suggested the drug-loaded hydrogels may be used as controlled release drug delivery systems. (author)

Effects of consumer food preparation on acrylamide formation.

Science.gov (United States)

Jackson, Lauren S; Al-Taher, Fadwa

2005-01-01

Acrylamide is formed in high-carbohydrate foods during high temperature processes such as frying, baking, roasting and extrusion. Although acrylamide is known to form during industrial processing of food, high levels of the chemical have been found in home-cooked foods, mainly potato- and grain-based products. This chapter will focus on the effects of cooking conditions (e.g. time/temperature) on acrylamide formation in consumer-prepared foods, the use of surface color (browning) as an indicator of acrylamide levels in some foods, and methods for reducing acrylamide levels in home-prepared foods. As with commercially processed foods, acrylamide levels in home-prepared foods tend to increase with cooking time and temperature. In experiments conducted at the NCFST, we found that acrylamide levels in cooked food depended greatly on the cooking conditions and the degree of "doneness", as measured by the level of surface browning. For example, French fries fried at 150-190 degrees C for up to 10 min had acrylamide levels of 55 to 2130 microg/kg (wet weight), with the highest levels in the most processed (highest frying times/temperatures) and the most highly browned fries. Similarly, more acrylamide was formed in "dark" toasted bread slices (43.7-610.7 microg/kg wet weight), than "light" (8.27-217.5 microg/kg) or "medium" (10.9-213.7 microg/kg) toasted slices. Analysis of the surface color by colorimetry indicated that some components of surface color ("a" and "L" values) correlated highly with acrylamide levels. This indicates that the degree of surface browning could be used as an indicator of acrylamide formation during cooking. Soaking raw potato slices in water before frying was effective at reducing acrylamide levels in French fries. Additional studies are needed to develop practical methods for reducing acrylamide formation in home-prepared foods without changing the acceptability of these foods.

Cytotoxicity and Acute Gastrointestinal Toxicity of Bacterial Cellulose-Poly (acrylamide-sodium acrylate Hydrogel: A Carrier for Oral Drug Delivery

Directory of Open Access Journals (Sweden)

Manisha Pandey 1,2 * , Hira Choudhury 1, Mohd Cairul Iqbal Mohd Amin 2

2016-12-01

Full Text Available Background: Preliminary safety evaluation of polymer intended to use as drug delivery carrier is essential. Methods: In this study polyacrylamide grafted bacterial cellulose (BC/AM hydrogel was prepared by microwave irradiation initiated free radical polymerization. The synthesized hydrogel was subjected to in vitro cytotoxicity and acute gastrointestinal toxicity studies to evaluate its biological safety as potential oral drug delivery carrier. Results: The results indicate that hydrogel was non cytotoxic and did not show any histopathological changes in GI tract after a high dose of oral administration. Conclusion: The results revealed that hydrogel composed of bacterial cellulose and polyacrylamide is safe as oral drug delivery carrier.

Synthesis and characterization of high performance superabsorbent hydrogels using bis[2-(methacryloyloxyethyl] phosphate as crosslinker

Directory of Open Access Journals (Sweden)

A. A. L. Goncalves

2016-03-01

Full Text Available Various superabsorbent polymers (SAPs were synthesized by free radical copolymerization at 70°C using acrylic acid (AA, potassium acrylate (KA, N-isopropyl acrylamide (NIPAM and sulfopropyl methacrylate potassium salt (SPM as monomers, bis[2-(methacryloyloxyethyl] phosphate (BMEP as crosslinker and potassium persulfate (KPS as initiator. The optimization of the synthesis led to the preparation of a SAP with very high water absorption ability, with a maximum swelling of 2618 g water/g dry hydrogel. The most promising SAP was fully characterized and the absorption capacities were studied at different pH and ionic strengths. When this SAP was mixed with soil, the mixture was able to lose water more slowly. Also, this material revealed high loading capacity and showed good releasing profiles using urea as model fertilizer. Due to these advantageous properties, the synthesized SAP can be used in agricultural applications.

Probing structure-antifouling activity relationships of polyacrylamides and polyacrylates.

Science.gov (United States)

Zhao, Chao; Zhao, Jun; Li, Xiaosi; Wu, Jiang; Chen, Shenfu; Chen, Qiang; Wang, Qiuming; Gong, Xiong; Li, Lingyan; Zheng, Jie

2013-07-01

We have synthesized two different polyacrylamide polymers with amide groups (polySBAA and polyHEAA) and two corresponding polyacrylate polymers without amide groups (polySBMA and polyHEA), with particular attention to the evaluation of the effect of amide group on the hydration and antifouling ability of these systems using both computational and experimental approaches. The influence of polymer architectures of brushes, hydrogels, and nanogels, prepared by different polymerization methods, on antifouling performance is also studied. SPR and ELISA data reveal that all polymers exhibit excellent antifouling ability to repel proteins from undiluted human blood serum/plasma, and such antifouling ability can be further enhanced by presenting amide groups in polySBAA and polyHEAA as compared to polySBMA and polyHEA. The antifouling performance is positively correlated with the hydration properties. Simulations confirm that four polymers indeed have different hydration characteristics, while all presenting a strong hydration overall. Integration of amide group with pendant hydroxyl or sulfobetaine group in polymer backbones is found to increase their surface hydration of polymer chains and thus to improve their antifouling ability. Importantly, we present a proof-of-concept experiment to synthesize polySBAA nanogels, which show a switchable property between antifouling and pH-responsive functions driven by acid-base conditions, while still maintaining high stability in undiluted fetal bovine serum and minimal toxicity to cultured cells. This work provides important structural insights into how very subtle structural changes in polymers can yield great improvement in biological activity, specifically the inclusion of amide group in polymer backbone/sidechain enables to obtain antifouling materials with better performance for biomedical applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

Acrylamide and Its Presence in Foods

Directory of Open Access Journals (Sweden)

Alper Karagoz

2009-04-01

Full Text Available Acrylamide is chemical matter which forms spontaneously as frying or cooking heat treatment enforced in foods. Though the said chemical is widely found in the fried or oven-cooked foods, it can also exist in the grilled foods prepared at homes or at large restaurants. However, no acrylamide has been found in the raw or boiled foods. Based on the studies made on acrylamide, and its observed biological effects, that chemical is suspected to be a human carcinogen. Neural destructions have been observed on the individuals who are exposed to this chemical. As yet, there isn’t any direct evidence about carcinogenic effects of acrylamide for human. In conclusion, we can say that acrylamide creates a risk for human health only in the cases of long term exposure to it. [TAF Prev Med Bull 2009; 8(2.000: 187-192

Non-fouling hydrogels of 2-hydroxyethyl methacrylate and zwitterionic carboxybetaine (meth)acrylamides

Czech Academy of Sciences Publication Activity Database

Kostina, Nina Yu.; Rodriguez-Emmenegger, Cesar; Houska, Milan; Brynda, Eduard; Michálek, Jiří

2012-01-01

Roč. 13, č. 12 (2012), s. 4164-4170 ISSN 1525-7797 R&D Projects: GA AV ČR KAN200520804; GA ČR GAP205/12/1702; GA ČR GAP106/12/1451 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : zwitterionic hydrogels * non-fouling properties * carboxybetaine Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.371, year: 2012

Cupula-Inspired Hyaluronic Acid-Based Hydrogel Encapsulation to Form Biomimetic MEMS Flow Sensors.

Science.gov (United States)

Kottapalli, Ajay Giri Prakash; Bora, Meghali; Kanhere, Elgar; Asadnia, Mohsen; Miao, Jianmin; Triantafyllou, Michael S

2017-07-28

Blind cavefishes are known to detect objects through hydrodynamic vision enabled by arrays of biological flow sensors called neuromasts. This work demonstrates the development of a MEMS artificial neuromast sensor that features a 3D polymer hair cell that extends into the ambient flow. The hair cell is monolithically fabricated at the center of a 2 μm thick silicon membrane that is photo-patterned with a full-bridge bias circuit. Ambient flow variations exert a drag force on the hair cell, which causes a displacement of the sensing membrane. This in turn leads to the resistance imbalance in the bridge circuit generating a voltage output. Inspired by the biological neuromast, a biomimetic synthetic hydrogel cupula is incorporated on the hair cell. The morphology, swelling behavior, porosity and mechanical properties of the hyaluronic acid hydrogel are characterized through rheology and nanoindentation techniques. The sensitivity enhancement in the sensor output due to the material and mechanical contributions of the micro-porous hydrogel cupula is investigated through experiments.

Polyelectrolyte Complex Nanoparticles of Poly(ethyleneimine and Poly(acrylic acid: Preparation and Applications

Directory of Open Access Journals (Sweden)

Martin Müller

2011-04-01

Full Text Available In this contribution we outline polyelectrolyte (PEL complex (PEC nanoparticles, prepared by mixing solutions of the low cost PEL components poly(ethyleneimine (PEI and poly(acrylic acid (PAC. It was found, that the size and internal structure of PEI/PAC particles can be regulated by process, media and structural parameters. Especially, mixing order, mixing ratio, PEL concentration, pH and molecular weight, were found to be sensible parameters to regulate the size (diameter of spherical PEI/PAC nanoparticles, in the range between 80–1,000 nm, in a defined way. Finally, applications of dispersed PEI/PAC particles as additives for the paper making process, as well as for drug delivery, are outlined. PEI/PAC nanoparticles mixed directly on model cellulose film showed a higher adsorption level applying the mixing order 1. PAC 2. PEI compared to 1. PEI 2. PAC. Surface bound PEI/PAC nanoparticles were found to release a model drug compound and to stay immobilized due to the contact with the aqueous release medium.

Formation of acrylamide in cheese bread

DEFF Research Database (Denmark)

Hedegaard, Rikke Susanne Vingborg; Sobrinho, Luis Gualberto De Andrade; Granby, Kit

2008-01-01

Low addition of grated Mozzarella cheese (13.4 g/100 g dough) resulted after baking for 20 min at 200 degrees C in a moderate increase of acrylamide from 4 ppb in buns without cheese to 7 ppb in the cheese buns as analyzed by a LCMS/MS technique. The effect was strongly dependent on the amount...... of cheese added, and addition of 23.7 g cheese resulted in 958 ppb acrylamide. For an o/w rapeseed oil emulsion as a food model heated under conditions similar to those persisting inside bread during baking, it was further shown that acrylamide formation also occurred in absence of reducing sugars....... In contrast, acrylamide was not observed in Pao de queijo a traditional Brazilian bread product made from fermented cassava flour, fresh eggs and a mixture of Brazilian Gouda type cheese and Mozzarella cheese pointing towards a role of eggs in protection against acrylamide formation....

Preparation of poly(polyethylene glycol methacrylate-co-acrylic acid) hydrogels by radiation and their physical properties

International Nuclear Information System (INIS)

Park, S.-E.; Nho, Y.-C.; Kim, H.-I.

2004-01-01

The pH-responsive copolymer hydrogels were prepared with the monomers of polyethylene glycol methacrylate and acrylic acid based on γ-ray irradiation technique. The gel content of these copolymer hydrogels varied depending on both the composition of monomers and the radiation dose. Maximum gel percent and degree of crosslinking were obtained at the composition of equal amount of comonomers. These copolymer hydrogels did not show any noticeable change in swelling at lower pH range. However they showed an abrupt increase in swelling at higher pH range due to the ionization of carboxyl groups. This pH-responsive swelling behavior was applied for the insulin carrier via oral delivery. Insulin-loaded copolymer hydrogels released most of their insulin in the simulated intestinal fluid which had a pH of 6.8 but not in the simulated gastric fluid which had a pH of 1.2

Effect of citric acid crosslinking cellulose-based hydrogels on osteogenic differentiation.

Science.gov (United States)

Raucci, M G; Alvarez-Perez, M A; Demitri, C; Giugliano, D; De Benedictis, V; Sannino, A; Ambrosio, L

2015-06-01

Understanding the relationships between material surface properties and cellular responses is essential to designing optimal material surfaces for implantation and tissue engineering. In this study, cellulose hydrogels were crosslinked using a non-toxic and natural component namely citric acid. The chemical treatment induces COOH functional groups that improve the hydrophilicity, roughness, and materials rheological properties. The physiochemical, morphological, and mechanical analyses were performed to analyze the material surface before and after crosslinking. This approach would help determine if the effect of chemical treatment on cellulose hydrogel improves the hydrophilicity, roughness, and rheological properties of the scaffold. In this study, it was demonstrated that the biological responses of human mesenchymal stem cell with regard to cell adhesion, proliferation, and differentiation were influenced in vitro by changing the surface chemistry and roughness. © 2014 Wiley Periodicals, Inc.

Acrylamide in Fried Potato Products

NARCIS (Netherlands)

Luning, Pieternel; Sanny, Maimunah

2016-01-01

High acrylamide levels have been detected in fried potato products. Dietary intake studies observed large differences in acrylamide between single foodstuffs, within food categories, and within batches of similarly processed products. FAO/WHO emphasized that causes of variation need to be

Evaluation of scission and crosslinking yields in γ-irradiated poly(acrylic acid) and poly(methacrylic acid) from weight- and Ζ-average molecular weights determined by sedimentation equilibrium

International Nuclear Information System (INIS)

Hill, D.J.T.; O'Donnell, J.H.; Winzor, C.L.; Winzor, D.J.

1990-01-01

Weight- and Ζ-average molecular weights, M-bar W (D) and M-bar Ζ (D), of poly(methacrylic acid) (PMMA) and poly(acrylic acid) (PAA) have been determined by sedimentation equilibrium in the ultracentrifuge after various doses D of γ-radiation in vacuum. Relationships between [M i (0)/M i (D)-1]/D and D (i=w or Ζ), derived recently by O'Donnell and coworkers, have been used to determine radiation chemical yields for scission and crosslinking of G(S)=6.0, G(X)=0 for PMAA and G(S)=0, G(X)=0.44 for PAA. Allowance was necessary for the effects of COOH decomposition on the average values of the molecular weight and partial specific volume for irradiated PAA. (author)

Occurrence of acrylamide carcinogen in Arabic coffee Qahwa, coffee and tea from Saudi Arabian market

Science.gov (United States)

Khan, Mohammad Rizwan; Alothman, Zeid Abdullah; Naushad, Mu; Alomary, Ahmed Khodran; Alfadul, Sulaiman Mohammed; Alsohaimi, Ibrahim Hotan; Algamdi, Mohammad Saad

2017-02-01

The present work describes the outcomes of the assessment on acrylamide contents in a number of thermally treated foods (Arabic coffee Qahwa, coffee and tea) obtained from the Saudi Arabian markets. A total of 56 food samples of different brands and origin were studied, the amounts of acrylamide in Arabic coffee Qahwa, coffee and tea were obtained in the range of 10 to 682 μg kg-1. In comparison to coffee (152-682 μg kg-1), the Arabic coffee Qahwa (73-108 μg kg-1) and tea (10-97 μg kg-1) contain lower amounts of acrylamide. Among the analyzed samples, the green tea contained low amounts of acrylamide ranged from 10 to 18 μg kg-1, and thus the green tea could be considered as a healthier hot drink. A great variation of acrylamide formation has been observed in these food products. This divergence may be due to the initial concentration of amino acids especially asparagines and reducing sugars in food products, in addition to roasting temperature and time, pH and water activity. The obtained data can also be used in epidemiological investigation to estimate the acrylamide exposure from nutritional survey.

Toward a versatile toolbox for cucurbit[n]uril-based supramolecular hydrogel networks through in situ polymerization.

Science.gov (United States)

Liu, Ji; Soo Yun Tan, Cindy; Lan, Yang; Scherman, Oren A

2017-09-15

The success of exploiting cucurbit[ n ]uril (CB[ n ])-based molecular recognition in self-assembled systems has sparked a tremendous interest in polymer and materials chemistry. In this study, polymerization in the presence of host-guest complexes is applied as a modular synthetic approach toward a diverse set of CB[8]-based supramolecular hydrogels with desirable properties, such as mechanical strength, toughness, energy dissipation, self-healing, and shear-thinning. A range of vinyl monomers, including acrylamide-, acrylate-, and imidazolium-based hydrophilic monomers, could be easily incorporated as the polymer backbones, leading to a library of CB[8] hydrogel networks. This versatile strategy explores new horizons for the construction of supramolecular hydrogel networks and materials with emergent properties in wearable and self-healable electronic devices, sensors, and structural biomaterials. © 2017 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 3105-3109.

A novel dextran hydrogel linking trans-ferulic acid for the stabilization and transdermal delivery of vitamin E.

Science.gov (United States)

Cassano, Roberta; Trombino, Sonia; Muzzalupo, Rita; Tavano, Lorena; Picci, Nevio

2009-05-01

Long-term exposure of the skin to UV light causes degenerative effects, which can be minimized by using antioxidant formulations. The major challenge in this regard is that a significant amount of antioxidant should reach at the site for effective photoprotection. However, barrier properties of the skin limit their use. In the present study, vitamin E (alpha-tocopherol) was loaded into a dextran hydrogel containing ferulic moieties, covalently linked, to improve its topical delivery, and also to increase its relative poor stability, which is due to direct exposure to UV light. Methacrylic groups were first introduced onto the dextran polymer backbones, then the obtained methacrylated dextran was copolymerized with aminoethyl methacrylate, and subsequently esterificated with trans-ferulic acid. The new biopolymer was characterized by Fourier transform infrared spectroscopy. The values of content of phenolic groups were determined. Its ability in inhibiting lipid peroxidation in rat liver microsomal membranes induced in vitro by a source of free radicals, that is tert-butyl hydroperoxide, was studied. Hydrogel was also characterized for swelling behaviour, vitamin E loading efficiency, release, and deposition on the rabbit skin. Additionally, vitamin E deposition was compared through hydrogels, respectively, containing and not containing trans-ferulic acid. The results showed that ferulate hydrogel was a more effective carrier in protecting vitamin E from photodegradation than hydrogel without antioxidant moieties. Then antioxidant hydrogel could be of potential use for cosmetic and pharmaceutical purposes as carrier of vitamin E that is an antioxidant that reduces erythema, photoaging, photocarcinogenesis, edema, and skin hypersensitivity associated with exposure to ultraviolet B (UVB) radiation, because of its protective effects.

Nanoscale Mobility of Aqueous Polyacrylic Acid in Dental Restorative Cements.

Science.gov (United States)

Berg, Marcella C; Benetti, Ana R; Telling, Mark T F; Seydel, Tilo; Yu, Dehong; Daemen, Luke L; Bordallo, Heloisa N

2018-03-28

Hydrogen dynamics in a time range from hundreds of femtoseconds to nanoseconds can be directly analyzed using neutron spectroscopy, where information on the inelastic and quasi-elastic scattering, hereafter INS and QENS, can be obtained. In this study, we applied these techniques to understand how the nanoscale mobility of the aqueous solution of polyacrylic acid (PAA) used in conventional glass ionomer cements (GICs) changes under confinement. Combining the spectroscopic analysis with calorimetric results, we were able to separate distinct motions within both the liquid and the GICs. The QENS analysis revealed that the self-diffusion translational motion identified in the liquid is also visible in the GIC. However, as a result of the formation of the cement matrix and its setting, both translational diffusion and residence time differed from the PAA solution. When comparing the local diffusion obtained for the selected GIC, the only noticeable difference was observed for the slow dynamics associated with the polymer chain. Additionally, over short-term aging, progressive water binding to the polymer chain occurred in one of the investigated GICs. Finally, a considerable change in the density of the GIC without progressive water binding indicates an increased polymer cross-linking. Taken together, our results suggest that accurate and deep understanding of polymer-water binding, polymer cross-linking, as well as material density changes occurring during the maturation process of GIC are necessary for the development of advanced dental restorative materials.

Acrylamide and 5-hydroxymethylfurfural formation during baking of biscuits: Part I: Effects of sugar type.

Science.gov (United States)

Nguyen, Ha T; Van der Fels-Klerx, H J Ine; Peters, Ruud J B; Van Boekel, Martinus A J S

2016-02-01

This study aimed to investigate the effects of sugar type on the reaction mechanism for formation of acrylamide and 5-hydroxymethylfurfural (HMF) during the baking of biscuits at 200°C using multiresponse modelling. Four types of biscuits were prepared: (1) with sucrose, (2) with glucose and fructose, (3) with fructose only and (4) with glucose only. Experimental data showed that HMF concentration was highest in biscuits with glucose and fructose, whereas acrylamide concentration was highest in biscuits with glucose, also having the highest asparagine concentration. Proposed mechanistic models suggested that HMF is formed via caramelisation and that acrylamide formation follows the specific amino acid route, i.e., reducing sugars react with asparagine to form the Schiff base before decarboxylation, to generate acrylamide without the Amadori rearrangement product and sugar fragmentation. Study results contribute to understanding chemical reaction pathways in real food products. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis of Poly (Amido-Amine) and Its Application for Removal of Metal Ions

International Nuclear Information System (INIS)

Siyam, T.; Abdel-Hamid, M.M.; El-Naggar, I.M.

1999-01-01

Poly (amido-amine) such as poly(acrylamide-acrylic acid-dimethylaminoethylmethacrylate) P(AM-AA-DMAEM) was prepared by gamma irradiation induced template polymerization of acrylic acid on in the presence of poly(acrylamide-dimethylaminoethylmethacrylate) as a template polymer. The polymerization was studied by a free radical mechanism in aqueous solution and the hydrogel was obtained. The swelling degree of the formed hydrogel increases by increasing the polymer/monomer molar ratio and decreases with increasing the monomer concentration. The swelling degree was also found to depend on the radiation dose. The results showed that the capacity of the obtained hydrogel was found to be maximum at polymer/monomer molar ratio of 1.3. The capacity of the polymeric materials increases with increasing the monomer concentration and decreases with increasing the radiation doses. The metal cations interact with polymeric chains to form a cross-linked structure after cation build-up. Tlus interaction occurs through complex formation between amide and amine groups with cations whereas the carboxylic group interacts by cation-exchange mechanism

Application of polyacrylic acid-poly-N,N-dimethyldiallylammonium chloride polyelectrolyte complexes for structuring of polluted soil of Semipalatinsk nuclear test site

International Nuclear Information System (INIS)

Sabantseva, T.; Bashenova, A.; Orazzhanova, L.K.; Yashkarova, M.G.; Bimendina, L.A.

2002-01-01

The present communication is devoted to investigation of structuring efficiency of polyacrylic acid-poly-N,N-dimethyldiallylammonium chloride (PAA-PDMDAACI) polyelectrolyte complexes. The granulometric analysis of selected soil samples before and after the treatment of aqueous solution of PAA, PDMDAACI and PAA-PDMDAACI complexes at different molar ratio of polymer components and polymer concentrations was carried out. Analysis shows that nonstoichiometric polyelectrolyte complex [PAA]:[PDMDAACI]=3:1 possesses the best structuring effect. But this result is worse than in the case using of [PAA]:[polyethylene glycol]=1:1 inter-polymer complex

Biomolecule-Responsive Hydrogels in Medicine.

Science.gov (United States)

Sharifzadeh, Ghorbanali; Hosseinkhani, Hossein

2017-12-01

Recent advances and applications of biomolecule-responsive hydrogels, namely, glucose-responsive hydrogels, protein-responsive hydrogels, and nucleic-acid-responsive hydrogels are highlighted. However, achieving the ultimate purpose of using biomolecule-responsive hydrogels in preclinical and clinical areas is still at the very early stage and calls for more novel designing concepts and advance ideas. On the way toward the real/clinical application of biomolecule-responsive hydrogels, plenty of factors should be extensively studied and examined under both in vitro and in vivo conditions. For example, biocompatibility, biointegration, and toxicity of biomolecule-responsive hydrogels should be carefully evaluated. From the living body's point of view, biocompatibility is seriously depended on the interactions at the tissue/polymer interface. These interactions are influenced by physical nature, chemical structure, surface properties, and degradation of the materials. In addition, the developments of advanced hydrogels with tunable biological and mechanical properties which cause no/low side effects are of great importance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controlled Release of Indomethacin from Smart Starch-Based Hydrogels Prepared Acrylic Acid and b-Cyclodextrin as a Nanocarrier

Directory of Open Access Journals (Sweden)

Hossein Ghasemzadeh Mohammadi

2017-01-01

Full Text Available Controlled release of drugs can reduce the undesired effects of drug level fluctuations, and diminish the side effects as well as improve the therapeutic outcome of the drugs. In recent year, the scope of the drug delivery systems has been greatly expanded by the development of various hydrogels. The present work has focused on the design of a pH sensitive drug delivery system (DDS based on starch, acrylic acid (AA and β-cyclodextrins for controlled delivery of indomethacin. The hydrogels were prepared via graft polymerization of acrylic acid (AA onto starch and β-cyclodextrins backbones by a free radical polymerization technique. Cyclodextrins are able to form water-soluble complexes with many lipophilic water-insoluble drugs. In aqueous solutions, the drug molecules located in the central cavity of the cyclodextrin are in a dynamic equilibrium with free drug molecules. The interaction of drug with the polymer was evidenced by FTIR spectroscopy and thermal gravimetric analysis (TGA. The morphology of the samples was examined by scanning electron microscopy (SEM. The results showed that the hydrogels have good porosity and provided high surface area for the loading and release of drugs. Drug release behavior was carried out at physiological conditions of phosphate buffer, pH 8. In basic pH (like the intestine medium the hydrogels released the indomethacin, but in acidic pH (like the stomach medium there was no tendency to drug release. By increasing the amount of cyclodextrin, the rate of drug loading and release increased due to the dynamic equilibrium and interaction between the loaded drug and the cyclodextrin. This study has demonstrated that the hydrogel matrices are potentially suitable for controlled-release systems.

Hyaluronic acid hydrogels with IKVAV peptides for tissue repair and axonal regeneration in an injured rat brain

International Nuclear Information System (INIS)

Wei, Y T; Tian, W M; Yu, X; Cui, F Z; Hou, S P; Xu, Q Y; Lee, In-Seop

2007-01-01

A biocompatible hydrogel of hyaluronic acid with the neurite-promoting peptide sequence of IKVAV was synthesized. The characterization of the hydrogel shows an open porous structure and a large surface area available for cell interaction. Its ability to promote tissue repair and axonal regeneration in the lesioned rat cerebrum is also evaluated. After implantation, the polymer hydrogel repaired the tissue defect and formed a permissive interface with the host tissue. Axonal growth occurred within the microstructure of the network. Within 6 weeks the polymer implant was invaded by host-derived tissue, glial cells, blood vessels and axons. Such a hydrogel matrix showed the properties of neuron conduction. It has the potential to repair tissue defects in the central nervous system by promoting the formation of a tissue matrix and axonal growth by replacing the lost tissue

In situ assembly of fibrinogen/hyaluronic acid hydrogel via knob-hole interaction for 3D cellular engineering

Directory of Open Access Journals (Sweden)

Shengjie Huang

2017-12-01

Full Text Available Hyaluronic acid (HA-based hydrogels have applied widely for biomedical applications due to its biocompatibility and biodegradability. However, the use of initiators or crosslinkers during the hydrogel formation may cause cytotoxicity and thereby impair the biocompatibility. Inspired by the crosslinking mechanism of fibrin gel, a novel HA-based hydrogel was developed via the in situ supramolecular assembly based on knob-hole interactions between fibrinogen and knob-grafted HA (knob-g-HA in this study. The knob-grafted HA was synthesized by coupling knob peptides (GPRPAAC, a mimic peptide of fibrin knob A to HA via Michael addition. Then the translucent fibrinogen/knob-g-HA hydrogels were prepared by simply mixing the solutions of knob-g-HA and fibrinogen at the knob/hole ratio of 1.2. The rheological behaviors of the fibrinogen/knob-g-HA hydrogels with the fibrinogen concentrations of 50, 100 and 200 mg/mL were evaluated, and it was found that the dynamic storage moduli (G′ were higher than the loss moduli (G″ over the whole frequency range for all the groups. The SEM results showed that fibrinogen/knob-g-HA hydrogels presented the heterogeneous mesh-like structures which were different from the honeycomb-like structures of fibrinogen/MA-HA hydrogels. Correspondingly, a higher swelling ratio was obtained in the groups of fibrinogen/knob-g-HA hydrogel. Finally, the cytocompatibility of fibrinogen/knob-g-HA hydrogels was proved by live/dead stainings and MTT assays in the 293T cells encapsulation test. All these results highlight the biological potential of the fibrinogen/knob-g-HA hydrogels for 3D cellular engineering.

Characterization of bioactive RGD peptide immobilized onto poly(acrylic acid) thin films by plasma polymerization

Energy Technology Data Exchange (ETDEWEB)

Seo, Hyun Suk; Ko, Yeong Mu; Shim, Jae Won [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, Gwangju (Korea, Republic of); Lim, Yun Kyong; Kook, Joong-Ki [Department of Oral Biochemistry, School of Dentistry, Chosun University, Gwangju (Korea, Republic of); Cho, Dong-Lyun [School of Applied Chemical Engineering and Center for Functional Nano Fine Chemicals, Chonnam National University, Gwangju (Korea, Republic of); Kim, Byung Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, MRC Center, Chosun University, Gwangju (Korea, Republic of)

2010-11-01

Plasma surface modification can be used to improve the surface properties of commercial pure Ti by creating functional groups to produce bioactive materials with different surface topography. In this study, a titanium surface was modified with acrylic acid (AA) using a plasma treatment and immobilized with bioactive arginine-glycine-aspartic acid (RGD) peptide, which may accelerate the tissue integration of bone implants. Both terminals containing the -NH{sub 2} of RGD peptide sequence and -COOH of poly(acrylic acid) (PAA) thin film were combined with a covalent bond in the presence of 1-ethyl-3-3-dimethylaminopropyl carbodiimide (EDC). The chemical structure and morphology of AA film and RGD immobilized surface were investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All chemical analysis showed full coverage of the Ti substrate with the PAA thin film containing COOH groups and the RGD peptide. The MC3T3-E1 cells were cultured on each specimen, and the cell alkaline phosphatase (ALP) activity were examined. The surface-immobilized RGD peptide has a significantly increased the ALP activity of MC3T3-E1 cells. These results suggest that the RGD peptide immobilization on the titanium surface has an effect on osteoblastic differentiation of MC3T3-E1 cells and potential use in osteo-conductive bone implants.

Diffusion coefficient, porosity measurement, dynamic and equilibrium swelling studies of Acrylic acid/Polyvinyl alcohol (AA/PVA hydrogels

Directory of Open Access Journals (Sweden)

Nazar Mohammad Ranjha

2015-06-01

Full Text Available Objective of the present work was to synthesize hydrogels of acrylic acid/polyvinyl alcohol (AA/PVA by free radical polymerization by using glutaradehyde (GA as crosslinkers. The hydrogels were evaluated for swelling, diffusion coefficient and network parameters like the average molecular weight between crosslink’s, polymer volume fraction in swollen state, number of repeating units between crosslinks and crosslinking density by using Flory-Huggins theory. It was found that the degree of swelling of AA/PVA hydrogels increases greatly within the pH range 5-7. The gel fraction and porosity increased by increasing the concentration of AA or PVA. Increase in degree of crosslinking, decreased the porosity and inverse was observed in gel fraction. Selected samples were loaded with metoprolol tartrate. Drug release was studied in USP hydrochloric acid solution of pH 1.2 and phosphate buffer solutions of pH 5.5 and 7.5. Various kinetics models like zero order, first order, Higuchi and Peppas model were used for in vitro kinetic studies. The results showed that the drug release followed concentration dependent effect (First order kinetics with non-Fickian diffusion. FTIR and SEM used to study the structure, crystallinity, compatibility, thermal stability and morphology of prepared and drug loaded hydrogels respectively.

An Enhanced Drought-Tolerant Method Using SA-Loaded PAMPS Polymer Materials Applied on Tobacco Pelleted Seeds

Directory of Open Access Journals (Sweden)

Yajing Guan

2014-01-01

Full Text Available Drought is one of the most important stress factors limiting the seed industry and crop production. Present study was undertaken to create novel drought-resistant pelleted seeds using the combined materials with superabsorbent polymer, poly(2-acrylamide-2-methyl propane sulfonic acid (PAMPS hydrogel, and drought resistance agent, salicylic acid (SA. The optimized PAMPS hydrogel was obtained as the molar ratio of 2-acrylamido-2-methyl-propanesulfonic acid (AMPS to potassium peroxydisulfate (KPS and N, N′-methylene-bis-acrylamide (MBA was 1 : 0.00046 : 0.00134. The hydrogel weight after swelling in deionized water for 24 h reached 4306 times its own dry weight. The water retention ratio (RR of PAMPS was significantly higher as compared with the control. It could keep as high as 85.3% of original weight after 30 min at 110°C; even at 25°C for 40 d, the PAMPS still kept RR at 33.67%. PAMPS disintegration ratio increased gradually and reached around 30% after embedding in soil or activated sludge for 60 d. In addition, there were better seed germination performance and seedling growth in the pelleted treatments with SA-loaded PAMPS hydrogel under drought stress than control. It suggested that SA-loaded PAMPS hydrogel, a nontoxic superabsorbent polymer, could be used as an effective drought resistance material applied to tobacco pelleted seeds.

Extended release of hyaluronic acid from hydrogel contact lenses for dry eye syndrome.

Science.gov (United States)

Maulvi, Furqan A; Soni, Tejal G; Shah, Dinesh O

2015-01-01

Current dry eye treatment includes delivering comfort enhancing agents to the eye via eye drops, but low residence time of eye drops leads to low bioavailability. Frequent administration leads to incompliance in patients, so there is a great need for medical device such as contact lenses to treat dry eye. Studies in the past have demonstrated the efficacy of hyaluronic acid (HA) in the treatment of dry eyes using eye drops. In this paper, we present two methods to load HA in hydrogel contact lenses, soaking method and direct entrapment. The contact lenses were characterized by studying their optical and physical properties to determine their suitability as extended wear contact lenses. HA-laden hydrogel contact lenses prepared by soaking method showed release up to 48 h with acceptable physical and optical properties. Hydrogel contact lenses prepared by direct entrapment method showed significant sustained release in comparison to soaking method. HA entrapped in hydrogels resulted in reduction in % transmittance, sodium ion permeability and surface contact angle, while increase in % swelling. The impact on each of these properties was proportional to HA loading. The batch with 200-μg HA loading showed all acceptable values (parameters) for contact lens use. Results of cytotoxicity study indicated the safety of hydrogel contact lenses. In vivo pharmacokinetics studies in rabbit tear fluid showed dramatic increase in HA mean residence time and area under the curve with lenses in comparison to eye drop treatment. The study demonstrates the promising potential of delivering HA through contact lenses for the treatment of dry eye syndrome.

In vitro release studies of vitamin B12 from poly N-vinyl pyrrolidone /starch hydrogels grafted with acrylic acid synthesized by gamma radiation

International Nuclear Information System (INIS)

Eid, M.

2008-01-01

Co-polymeric hydrogels containing N-vinyl pyrrolidone and starch grafted with acrylic acid were synthesized by gamma radiation. Their gel contents, grafting process and swelling were evaluated. The gels were also characterized by thermal gravimetric analysis. The gel content found to be increase with increasing the irradiation dose up to 50 kGy then decrease. The grafting percent increase by increasing the percentage of acrylic acid in the grafted hydrogels. The thermal stability and the rate of the thermal decomposition showed to be changed according to the different composition of the hydrogels. It also showed a decrease in the maximum rate of the thermal decomposition by the increasing of the irradiation dose from 20 to 30 kGy and increases by increasing the irradiation dose from 30 to 70 kGy. The hydrogels loaded with vitamin B 12 as drug model, demonstrated a decrease release in acidic medium than the neutral one

Infrared spectral studies of various metal polyacrylates

International Nuclear Information System (INIS)

McCluskey, P.H.; Snyder, R.L.; Condrate, R.A. Sr.

1989-01-01

A new process for the production of high surface area, high reactivity ceramic oxide powders involves the bonding of metal cations to polymeric polyacrylate chains. This process results in the formation of a gelatinous metal polyacrylate precipitate which can be easily removed from the mother liquor, and then calcined to form a high density ceramic oxide. Using FTIR spectroscopy, the nature of the structural arrangements has been studied for metal complexes in the yttrium, lanthanum, aluminum, cerium, copper, and iron polyacrylates. Interpretation of the infrared spectra indicates that two types of metal complex formation occur in these precipitates, involving bidentate or bridging interactions. The type that is observed for a particular metal ion is dependent on its metal ion size

The evaluation of temperature and pH influences on equilibrium swelling of poly(n-isopropylacrylamide-co-acrylic acid hydrogels

Directory of Open Access Journals (Sweden)

Zdravković Aleksandar S.

2017-01-01

Full Text Available Hydrogels are synthesized by the method of radical polymerization of monomers: N-isopropylacrylamide (NIPAM and acrylic acid (AA. Characterization of poly(N-isopropylacrylamide- co-acrylic acid hydrogels, p(NIPAM/AA, has been performed by Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD and by determination of the swelling behaviour in aqueous solutions at different temperatures (25, 31 and 37°C and pH values (2.2, 4.5, 6 and 6.8. After lyophilisation in the solution at pH 6 and temperature of 25°C, p(NIPAM/AA hydrogels have rapidly reached equilibrium degree of swelling, αe, in comparison to non-lyophilized samples. The mechanism of solvent transport within matrix in lyophilized samples corresponds to less Fickian diffusion, whereas Super case II diffusion is characteristic for non-lyophilized samples. p(NIPAM/AA hydrogel with 1.5 mol% of ethylene glycol dimethacrylate (EGDM at the temperature of 25°C and pH 6.8, has reached the highest swelling equilibrium degree, αe = 259.8. The results of swelling studies have shown that p(NIPAM/AA hydrogels can be classified as superabsorbent polymers (SAPs. For the evaluation of pH and temperature influences on synthesized hydrogels swelling, a full three-level experimental design has been used. Two-factor interaction model (2FI is the most optimal model of a full three-level experimental design for representing the swelling equilibrium degree of p(NIPAM/AA hydrogels as a function of investigated parameters, i.e., temperature and pH. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-34012

Enzyme-mediated hyaluronic acid-tyramine hydrogels for the propagation of human embryonic stem cells in 3D.

Science.gov (United States)

Xu, Keming; Narayanan, Karthikeyan; Lee, Fan; Bae, Ki Hyun; Gao, Shujun; Kurisawa, Motoichi

2015-09-01

The propagation of human embryonic stem cells (hESCs) in three-dimensional (3D) scaffolds facilitates the cell expansion process and supplies pluripotent cells of high quality for broad-spectrum applications in regenerative medicine. Herein, we report an enzyme-mediated hyaluronic acid-tyramine (HA-Tyr) hydrogel that encapsulated and propagated hESCs in 3D. HA-Tyr hydrogels were formed by crosslinking the tyramine moieties with horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). By changing the HRP and H2O2 concentration, we prepared HA-Tyr hydrogels of different mechanical strength and studied the self-renewal properties of hESCs in these scaffolds. We observed that both the chemical composition and mechanical strength of substrates were important factors affecting cell proliferation and pluripotency. The HA-Tyr hydrogel with a compressive modulus of ∼350Pa supported the proliferation of hESCs at the pluripotent state in both mTeSR1 medium and mouse embryonic fibroblast (MEF)-conditioned medium. Immunohistochemical analyses revealed that hESCs proliferated well and formed spheroid structures in 3D, without undergoing apoptosis. The hESCs cultured in HA-Tyr hydrogels showed high expression of CD44 and pluripotency markers. These cells exhibited the capability to form cell derivatives of all three embryonic germ layers in vitro and in vivo. In addition, the genetic integrity of the hESCs was unaffected in the 3D cultivation system. The scope of this study is to provide a stable 3D cultivation system for the expansion of human embryonic stem cells (hESCs) towards clinical applications. We report an enzyme mediated hyaluronic acid-tyramine (HA-Tyr) hydrogel that encapsulated and propagated hESCs in 3D. Unlike other HA-based photo-crosslinked hydrogel systems reported, we investigated the effects of mechanical strength of hydrogels on the self-renewal properties of hESCs in 3D. Then, we characterized hESCs cultured in hydrogels with lower mechanical strength

The acrylamide content of smokeless tobacco products.

Science.gov (United States)

McAdam, Kevin; Kimpton, Harriet; Vas, Carl; Rushforth, David; Porter, Andrew; Rodu, Brad

2015-01-01

There is considerable interest from a regulatory and public health perspective in harmful and potentially harmful constituents in tobacco products, including smokeless tobacco products (STPs). A wide range of commercial STPs from the US and Sweden, representing 80-90 % of the 2010 market share for all the major STP categories in these two countries, were analysed for the IARC Group 2A carcinogen acrylamide. These STPs comprised the following styles: Swedish loose and portion snus, US snus, chewing tobacco, moist snuff, dry snuff, soft pellet, hard pellet and plug. Acrylamide was detected in all the products tested and quantified in all but one product. Concentrations ranged from 62 to 666 ng/g wet weight basis (WWB). The average levels of acrylamide (WWB) by type of STP were not significantly different (p > 0.05) except for US snus which had, on average, greater levels but with a very wide range of individual levels according to the manufacturer. Acrylamide levels in STPs were significantly and positively correlated with pH, but not with levels of either reducing sugars or ammonia nitrogen. Levels of acrylamide increased by sixfold or more (on a dry weight basis) during manufacture of a snus sample and then decreased during subsequent storage for up to 22 weeks. Acrylamide generation in tobacco generally appears to occur at lower temperatures, but longer time scales than found with food production. Acrylamide is a common contaminant of STPs, formed through heat treatment of tobacco. Our data show that exposure to acrylamide from consumption of STPs is small compared with exposure from food consumption or cigarette smoking.

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

Science.gov (United States)

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

2017-07-01

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

Preparation of the copolymer of acrylic acid and acrylamide grafted onto polyethylene and its complexation with samarium ion

International Nuclear Information System (INIS)

Kido, Junji; Akiba, Hideto; Nishide, Hiroyuki; Tsuchida, Eishun; Omichi, Hideki; Okamoto, Jiro.

1986-01-01

Acrylic acid (AA) and acrylamide (AAm) were graft-copolymerized onto polyethylene (PE) powder by the pre-irradiation method. Complex formation constants of Sm ion with the PE powder grafted with both AA and AAm (PE-g-(AA-co-AAm)) were larger than those with the PE powder grafted with AA (PE-g-AA). Sm ion was efficiently separated from the solution containing both Sm ion and a transition metal ion such as Cu ion. Even after the γ-ray irradiation on PE-g-(AA-co-AAm) and PE-g-AA, the adsorption did not decrease. (author)

Poly(acrylic acid) conjugated hollow mesoporous carbon as a dual-stimuli triggered drug delivery system for chemo-photothermal synergistic therapy

Energy Technology Data Exchange (ETDEWEB)

Li, Xian; Liu, Chang; Wang, Shengyu; Jiao, Jian; Di, Donghua; Jiang, Tongying; Zhao, Qinfu, E-mail: zqf021110505@163.com; Wang, Siling, E-mail: silingwang@syphu.edu.cn

2017-02-01

In this work, we described the development of the redox and pH dual stimuli-responsive drug delivery system and combination of the chemotherapy and photothermal therapy for cancer treatment. The poly(acrylic acid) (PAA) was conjugated on the outlets of hollow mesoporous carbon (HMC) via disulfide bonds. PAA was used as a capping to block drug within the mesopores of HMC for its lots of favorable advantages, such as good biocompatibility, appropriate molecular weight to block the mesopores of HMC, extension of the blood circulation, and the improvement of the dispersity of the nano-carriers in physiological environment. The DOX loaded DOX/HMC-SS-PAA had a high drug loading amount up to 51.9%. The in vitro drug release results illustrated that DOX/HMC-SS-PAA showed redox and pH dual-responsive drug release, and the release rate could be further improved by the near infrared (NIR) irradiation. Cell viability experiment indicated that DOX/HMC-SS-PAA had a synergistic therapeutic effect by combination of chemotherapy and photothermal therapy. This work suggested that HMC-SS-PAA exhibited dual-responsive drug release property and could be used as a NIR-adsorbing drug delivery system for chemo-photothermal synergistic therapy. - Highlights: • Poly(acrylic acid) was grafted on hollow mesoporous carbon (HMC) via disulfide bonds. • The grafted PAA could increase the biocompatibility and stability of HMC. • The DOX-loaded DOX/HMC-SS-PAA had a high drug loading efficiency up to 51.9%. • DOX/HMC-SS-PAA showed redox/pH dual-responsive and NIR-triggered drug release. • DOX/HMC-SS-PAA showed a chemo/photothermal synergistic therapy effect.

Poly(acrylic acid) conjugated hollow mesoporous carbon as a dual-stimuli triggered drug delivery system for chemo-photothermal synergistic therapy

International Nuclear Information System (INIS)

Li, Xian; Liu, Chang; Wang, Shengyu; Jiao, Jian; Di, Donghua; Jiang, Tongying; Zhao, Qinfu; Wang, Siling

2017-01-01

In this work, we described the development of the redox and pH dual stimuli-responsive drug delivery system and combination of the chemotherapy and photothermal therapy for cancer treatment. The poly(acrylic acid) (PAA) was conjugated on the outlets of hollow mesoporous carbon (HMC) via disulfide bonds. PAA was used as a capping to block drug within the mesopores of HMC for its lots of favorable advantages, such as good biocompatibility, appropriate molecular weight to block the mesopores of HMC, extension of the blood circulation, and the improvement of the dispersity of the nano-carriers in physiological environment. The DOX loaded DOX/HMC-SS-PAA had a high drug loading amount up to 51.9%. The in vitro drug release results illustrated that DOX/HMC-SS-PAA showed redox and pH dual-responsive drug release, and the release rate could be further improved by the near infrared (NIR) irradiation. Cell viability experiment indicated that DOX/HMC-SS-PAA had a synergistic therapeutic effect by combination of chemotherapy and photothermal therapy. This work suggested that HMC-SS-PAA exhibited dual-responsive drug release property and could be used as a NIR-adsorbing drug delivery system for chemo-photothermal synergistic therapy. - Highlights: • Poly(acrylic acid) was grafted on hollow mesoporous carbon (HMC) via disulfide bonds. • The grafted PAA could increase the biocompatibility and stability of HMC. • The DOX-loaded DOX/HMC-SS-PAA had a high drug loading efficiency up to 51.9%. • DOX/HMC-SS-PAA showed redox/pH dual-responsive and NIR-triggered drug release. • DOX/HMC-SS-PAA showed a chemo/photothermal synergistic therapy effect.

Reduction of acrylamide in whole-wheat bread by combining lactobacilli and yeast fermentation.

Science.gov (United States)

Nasiri Esfahani, Behnaz; Kadivar, Mahdi; Shahedi, Mohammad; Soleimanian-Zad, Sabihe

2017-11-01

This study mainly focuses on a strategy for reducing acrylamide content in whole-wheat bread by combining lactobacilli and yeast in sourdough breadmaking. Combinations of sourdough (fermented dough using different Lactobacillus strains including Lactobacillus plantarum PTCC 1896 [probiotic], L. sakei DSM 20,017, L. rhamnosus DSM 20,021, and L. delbrueckii DSM 20,081) and yeast, in comparison with yeast alone, were used for breadmaking. The results showed that acrylamide levels in breads fermented using sourdough+yeast were in all cases much lower (6.9-20 μg/kg on a dry weight basis [d.b.]) than those in the yeast-only fermented bread (47.6 μg/kg d.b.). Significant (p bread (r = 0.925, p breads and either the reducing sugar or free amino acid contents in dough samples. According to the different effects of Lactobacillus strains, it could be concluded that the acrylamide reducing potential of lactobacilli was strain-specific, with L. rhamnosus being the most effective. This suggests that sourdough fermentation with appropriate Lactobacillus strains can be used as an advantageous technology to reduce the acrylamide content of whole-wheat breads.

Novel Nanocomposite Optical Plastics: Dispersion of Titanium in Polyacrylates

Directory of Open Access Journals (Sweden)

Gunjan Suri

2010-01-01

Full Text Available Polyacrylates have become the preferred materials for optical applications replacing the conventionally used glass due to their superior optical clarity. The major disadvantage with polyacrylates is their low (1.40–1.50 refractive index besides their poor impact resistance. The improvements in refractive index as well as mechanical properties can be achieved by way of incorporation of metals or metal compounds in the matrix. A novel methodology for the incorporation of high refractive index metals into low refractive index polymeric materials to improve the refractive index and impact resistance of the latter has been developed. With the in-situ formation of nanoparticles of TiO2, the refractive index of polyacrylates improved from 1.45 to 1.53 and the Abbe number increased from 40 to 57. One of the interesting dimension of this study pertains to the possibility of tailor-making of the two key optical properties of materials by way of varying the amount of TiO2 being formed in-situ. Thermal stability and impact resistance of nano dispersed (4.3% by wt. of Ti polyacrylates are found to be better than the neat polyacrylates. Moreover, TiO2-containing polyacrylate is of light weight. TEM, SEM, and IR analysis confirms the in-situ formation of nanoparticles of TiO2. Gamma irradiation has been used as an eco-friendly technique for polymerization. The developed compositions can be cast polymerized into clear and bubble free material for optical applications.

Synthesis and Characterization of pH and Thermo Dual-Responsive Hydrogels with a Semi-IPN Structure Based on N-Isopropylacrylamide and Itaconamic Acid.

Science.gov (United States)

Rwei, Syang-Peng; Tuan, Huynh Nguyen Anh; Chiang, Whe-Yi; Way, Tun-Fun

2018-04-28

A series of semi-interpenetrating polymer network (semi-IPN) hydrogels were synthesized and investigated in this study. Linear copolymer poly( N -isopropylacrylamide-co-itaconamic acid) p(NIPAM-co-IAM), which is formed by copolymerization of N -isopropylacrylamide (NIPAM) and itaconamic acid (IAM, 4-amino-2-ethylene-4-oxobutanoic acid), was introduced into a solution of NIPAM to form a series of pH and thermo dual-responsive p(NIPAM-co-IAM)/pNIPAM semi-IPN hydrogels by free radical polymerization. The structural, morphological, chemical, and physical properties of the linear copolymer and semi-IPN hydrogels were investigated. The semi-IPN hydrogel showed high thermal stability according to thermal gravimetric analyzer (TGA). Scanning electronic microscopy (SEM) images showed that the pore size was in the range of 119~297 µm and could be controlled by the addition ratio of the linear copolymer in the semi-IPN structure. The addition of linear copolymer increased the fracture strain from 57.5 ± 2.9% to 91.1 ± 4.9% depending on the added amount, while the compressive modulus decreased as the addition increased. Moreover, the pH and thermo dual-responsive properties were investigated using differential scanning calorimetry (DSC) and monitoring the swelling behavior of the hydrogels. In deionized (DI) water, the equilibrium swelling ratio of the hydrogels decreased as the temperature increased from 20 °C to 50 °C, while it varied in various pH buffer solutions. In addition, the swelling and deswelling rates of the hydrogels also significantly increased. The results indicate that the novel pH-thermo dual-responsive semi-IPN hydrogels were synthesized successfully and may be a potential material for biomedical, drug delivery, or absorption application.

Selective adsorption of Pb (II) ions by amylopectin-g-poly (acrylamide-co-acrylic acid): A bio-degradable graft copolymer.

Science.gov (United States)

Sasmal, Dinabandhu; Maity, Jayanta; Kolya, Haradhan; Tripathy, Tridib

2017-04-01

Amylopectin-g-poly (acrylamide-co-acrylic acid) [AP-g-poly (AM-co-AA)] was synthesised in water medium by using potassium perdisulphate as an initiator. The graft copolymer was characterized by molecular weight determination by size exclusion chromatography (SEC), fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscope (SEM) studies, thermal analysis, measurement of neutralisation equivalent and biodegradation studies. The graft copolymer was used for Pb (II) ion removal from aqueous solution. The Pb (II) ion removal capacity of the graft copolymer was also compared with another laboratory developed graft copolymer Amylopectin-g-poly (acrylamide) (AP-g-PAM). Both the graft copolymers were also used for the competitive metal ions removal with Pb (II)/Cd (II), Pb (II)/Zn (II), Pb (II)/Ni (II), Pb (II)/Cu (II) pairs separately under similar conditions. AP-g-poly (AM-co-AA) showed better Pb (II) ion adsorbing power over AP-g-PAM and also much selective towards Pb (II) ions. The adsorption follows a second order rate equation and Langmuir isotherm model. Copyright © 2017 Elsevier B.V. All rights reserved.

Biodegradation of New Polymer Foundry Binders for the Example of the Composition Polyacrylic Acid/Starch

Directory of Open Access Journals (Sweden)

Beata Grabowska

2011-04-01

Full Text Available The investigations on the biodegradation process pathway of the new polymer binders for the example of water soluble compositionpolyacrylic acid/starch are presented in the hereby paper. Degradation was carried out in water environment and in a soil. Thedetermination of the total oxidation biodegradation in water environment was performed under laboratory conditions in accordance with the static water test system (Zahn-Wellens method, in which the mixture undergoing biodecomposition contained inorganic nutrient,activated sludge and the polymer composition, as the only carbon and energy source. The biodecomposition progress of the polymercomposition sample in water environment was estimated on the basis of the chemical oxygen demand (COD measurements and thedetermination the biodegradation degree, Rt, during the test. These investigations indicated that the composition polyacrylic acid/starchconstitutes the fully biodegradable material in water environment. The biodegradation degree Rt determined in the last 29th day of the test duration achieved 65%, which means that the investigated polymer composition can be considered to be fully biodegradable.During the 6 months biodegradation process of the cross-linked sample of the polymer composition in a garden soil several analysis ofsurface and structural changes, resulting from the sample decomposition, were performed. Those were: thermal analyses (TG-DSC,structural analyses (Raman spectroscopy and microscopic analyses (optical microscopy, AFM.

Electroactive behavior assessment of poly(acrylic acid)-graphene oxide composite hydrogel in the detection of cadmium

NARCIS (Netherlands)

Bejarano-Jimenez, A.; Escobar-Barrios, V.A.; Kleijn, J.M.; Oritz-Ledon, C.A.; Chazaro-Ruiz, L.F.

2014-01-01

Super absorbent polymers of acrylic acid-graphene oxide (PAA-GO) were synthesized with different percentage of chemical neutralization (0, 10, and 20%) of the acrylic acid monomer before its polymerization. The influence of their swelling and adsorption/desorption capacity of cadmium ions in aqueous

Synthetic poly(amino acid) hydrogels with incorporated cell-adhesion peptides for tissue engineering

Czech Academy of Sciences Publication Activity Database

Studenovská, Hana; Vodička, Petr; Proks, Vladimír; Hlučilová, Jana; Motlík, Jan; Rypáček, František

2010-01-01

Roč. 4, č. 6 (2010), s. 454-463 ISSN 1932-6254 R&D Projects: GA AV ČR KJB400500801; GA MŠk 1M0538 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z50450515 Keywords : polyamino acid * hydrogel * porosity Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.534, year: 2010

A method for the determination of acrylamide in a broad variety of processed foods by GC-MS using xanthydrol derivatization.

Science.gov (United States)

Yamazaki, Kumiko; Isagawa, Satoshi; Kibune, Nobuyuki; Urushiyama, Tetsuo

2012-01-01

A novel GC-MS method was developed for the determination of acrylamide, which is applicable to a variety of processed foods, including potato snacks, corn snacks, biscuits, instant noodles, coffee, soy sauces and miso (fermented soy bean paste). The method involves the derivatization of acrylamide with xanthydrol instead of a bromine compound. Isotopically labelled acrylamide (d₃-acrylamide) was used as the internal standard. The aqueous extract from samples was purified using Sep-Pak™ C₁₈ and Sep-Pak™ AC-2 columns. For amino acid-rich samples, such as miso or soy sauce, an Extrelut™ column was used for purification or extraction. After reaction with xanthydrol, the resultant N-xanthyl acrylamide was determined by GC-MS. The method was validated for various food matrices and showed good linearity, precision and trueness. The limit of detection and limit of quantification ranged 0.5-5 and 5-20 µg kg⁻¹), respectively. The developed method was applied as an exploratory survey of acrylamide in Japanese foods and the method was shown to be applicable for all samples tested.

Adsorption of {alpha}-amylase onto poly(N-vinyl 2-pyrrolidone/itaconic acid) hydrogels

Energy Technology Data Exchange (ETDEWEB)

Tuemtuerk, Hayrettin; Caykara, Tuncer; Kantoglu, Oemer; Gueven, Olgun

1999-05-02

{alpha}-Amylase enzyme was adsorbed on poly(N-vinyl 2-pyrrolidone/itaconic acid) (P(VP/IA)) hydrogels prepared by irradiating the ternary mixtures of VP/IA/water by {gamma}-rays at ambient temperature. The adsorption capacity of the hydrogels was determined to increase from 2.30 to 3.40 mg {alpha}-amylase/g dry gel with increasing amount of IA in gel system. Kinetic parameters were calculated as 2.51 g/dm{sup 3} for K{sub m} and 1.67x10{sup -3} g/dm{sup 3} min for V{sub max} for free enzyme and in the range of 3.88-5.02 g/dm{sup 3} for K{sub m} and 1.62x10{sup -3}-2.27 x 10{sup -3} g/dm{sup 3} min for V{sub max} depending on the amount of IA in the hydrogel. Enzyme activities were found to increase from 49.9% to 77.4% with increasing amount of IA in the gel system and retained their activities for one month storage. On the other hand, the free enzyme loses its activity completely after 20 days.

Light scattering measurement of sodium polyacrylate products

Science.gov (United States)

Lama, Nisha; Norwood, David; Boone, Steven; Massie-Boyer, Valerie

2015-03-01

In the presentation, we will describe the use of a multi-detector HPLC incorporating the DAWN EOS multi-angle laser light scattering (MALLS) detector to measure the properties such as molecular weight, RMS radius, contour and persistence length and polydispersity of sodium polyacrylate products. The samples of sodium polyacrylate are used in various industries as thickening agents, coating dispersants, artificial snow, laundry detergent and disposable diapers. Data and results obtained from the experiment will be presented.

Radiation-induced synthesis and swelling properties of p(2-hydroxyethyl methacrylate-co-itaconic acid-co-oligo(ethylene glycol) acrylate) copolymeric hydrogels

International Nuclear Information System (INIS)

Micic, M.; Suljovrujic, E.

2011-01-01

Complete text of publication follows. Since it is presumed that by incorporation of pH-responsive (IA) and temperature-responsive (OEGA) co-monomers it is possible to prepare P(HEMA-co-IA-co-OEGA) hydrogels with duel (pH and thermo) responsiveness, the main purpose of this paper is to investigate the influence of different mole fractions of IA and especially OEGA on the diversity of the swelling properties of obtained hydrogels. For that reason, a series of copolymeric hydrogels with different mole ratios of 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA) and oligo(ethylene glycol) acrylates (OEGA) was synthesized by gamma radiation. The obtained hydrogels were characterized by swelling studies in the wide pH (2.2-9.0) and temperature range (25-70 deg C), confirming dual (pH and thermo) responsiveness and a large variation in swelling capability. It was observed that the equilibrium swelling of P(HEMA-co-IA-co-OEGA) hydrogels, for a constant amount of IA, increases progressively with increasing in OEGA share. On the other hand, the dissociation of carboxyl (-COOH) groups from IA occurs at pH > 4; therefore, small mole fractions of IA render good pH sensitivity and a large increase in the swelling capacity of these hydrogels at higher pH values. Additional characterization of structure and properties was conducted by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and mechanical measurements, confirming that the inherent properties of the P(HEMA-co-IA-co-OEGA) hydrogels can be significantly tuned by variation in their composition. According to all presented, it seems that the obtained copolymeric hydrogels can be a beneficial synergetic combination for controlled delivery of bioactive molecules such as drugs, nucleic acids, peptides, and proteins.

Dual Salt- and Thermo-Responsive Programmable Bilayer Hydrogel Actuators with Pseudo-Interpenetrating Double-Network Structures.

Science.gov (United States)

Xiao, Shengwei; Zhang, Mingzhen; He, Xiaomin; Huang, Lei; Zhang, Yanxian; Ren, Baiping; Zhong, Mingqiang; Chang, Yung; Yang, Jintao; Zheng, Jie

2018-06-07

Development of smart soft actuators is highly important for fundamental research and industrial applications, but has proved to be extremely challenging. In this work, we present a facile, one-pot, one-step method to prepare dual-responsive bilayer hydrogels, consisting of a thermos-responsive poly(N-isopropyl acrylamide) (polyNIPAM) layer and a salt-responsive poly(3-(1-(4-vinylbenzyl)-1H-imidazol-3-ium-3-yl)propane-1-sulfonat) (polyVBIPS) layer. Both polyNIPAM and polyVBIPs layers exhibit a completely opposite swelling/shrinking behavior, where polyNIPAM shrinks (swells) but polyVBIPS swells (shrinks) in salt solution (water) or at high (low) temperatures. By tuning NIPAM:VBIPS ratios, the resulting polyNIPAM/polyVBIPS bilayer hydrogels enable to achieve fast and large-amplitude bidirectional bending in response to temperatures, salt concentrations, and salt types. Such bidirectional bending, bending orientation and degree can be reversibly, repeatedly, and precisely controlled by salt- or temperature-induced cooperative, swelling-shrinking properties from both layers. Based on their fast, reversible, bidirectional bending behavior, we further design two conceptual hybrid hydrogel actuators, serving as a six-arm gripper to capture, transport, and release an object and an electrical circuit switch to turn on-and-off a lamp. Different from the conventional two or multi-step methods for preparation of bilayer hydrogels, our simple, one-pot, one-step method and a new bilayer hydrogel system provide an innovative concept to explore new hydrogel-based actuators through combining different responsive materials that allow to program different stimulus for soft and intelligent materials applications.

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...

Superabsorbent hydrogels via graft polymerization of acrylic acid from chitosan-cellulose hybrid and their potential in controlled release of soil nutrients.

Science.gov (United States)

Essawy, Hisham A; Ghazy, Mohamed B M; El-Hai, Farag Abd; Mohamed, Magdy F

2016-08-01

Superabsorbent polymers fabricated via grafting polymerization of acrylic acid from chitosan (CTS) yields materials that suffer from poor mechanical strength. Hybridization of chitosan with cellulose (Cell) via chemical bonding using thiourea formaldehyde resin increases the flexibility of the produced hybrid (CTS/Cell). The hybridization process and post graft polymerization of acrylic acid was followed using Fourier transform infrared (FTIR). Also, the obtained structures were homogeneous and exhibited uniform surface as could be shown from imaging with scanning electron microscopy (SEM). Thus, the polymers derived from the grafting of polyacrylic acid from (CTS/Cell) gave rise to much more mechanically robust structures ((CTS/Cell)-g-PAA) that bear wide range of pH response due to presence of chitosan and polyacrylic acid in one homogeneous entity. Additionally, the obtained structures possessed greater water absorbency 390, 39.5g/g in distilled water and saline (0.9wt.% NaCl solution), respectively, and enhanced retention potential even at elevated temperatures as revealed by thermogravimetric analysis (TGA). This could be explained by the high grafting efficiency (GE%), 86.4%, and grafting yield (GY%), 750%. The new superabsorbent polymers proved to be very efficient devices for controlled release of fertilizers into the soil which expands their use in agriculture and horticultural applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Assessing phytoremediation potentials of selected tropical plants for acrylamide

Science.gov (United States)

In biotechnology, acrylamide is being used in DNA and RNA analysis using the polyacrylamide gel electrophoreses procedure. Polymerized acrylamide is degraded into acrylamide through time; it is converted into a hazardous contaminant that is carcinogenic and neurotoxic to animals and humans. Because ...

Surface grafted chitosan gels. Part I. Molecular insight into the formation of chitosan and poly(acrylic acid) multilayers

DEFF Research Database (Denmark)

Liu, Chao; Thormann, Esben; Claesson, Per M.

2014-01-01

Composite polyelectrolyte multilayers of chitosan and low molecular weight poly(acrylic acid) (PAA) have been assembled by sequential adsorption as a first step toward building a surface anchored chitosan gel. Silane chemistry was used to graft the first chitosan layer to prevent film detachment...... and decomposition. The assembly process is characterized by nonlinear growth behavior, with different adsorption kinetics for chitosan and PAA. In situ analysis of the multilayer by means of surface sensitive total internal reflection Raman (TIRR) spectroscopy, combined with target factor analysis of the spectra...... molecular weight chitosan shows a similar behavior, although to a much lower extent. Our data demonstrate that the charged monomeric units of chitosan are mainly compensated by carboxylate ions from PAA. Furthermore, the morphology and mechanical properties of the multilayers were investigated in situ using...

Complexing blends of polyacrylic acid-polyethylene glycol and poly(ethylene-co-acrylic acid)-polyethylene glycol as shape stabilized phase change materials

International Nuclear Information System (INIS)

Alkan, Cemil; Günther, Eva; Hiebler, Stefan; Himpel, Michael

2012-01-01

Highlights: ► Complexing groups to PEGs in a polymer could stabilize PEG at different molecular weights. ► Shape stabilized PEGs for thermal energy storage are prepared using compounds with interacting groups. ► Phase change temperature of PEGs could be changed using a complexing copolymer with acid groups. - Abstract: Blends of poly(ethylene glycol) (PEG) at 1000, 6000, and 10,000 g/mole average molecular weights and poly(acrylic acid) (PAA) or poly(ethylene-co-acrylic acid) (EcoA) have been prepared by solution blending and accounted for thermal energy storage properties as shape stabilized polymer blends. The blends have been analyzed using Fourier transform infrared (FT-IR) spectroscopy and differential scanning calorimetry (DSC) techniques. Total thermal energy values of the complexes have been determined by the method of Mehling et al. As a result of the investigation it is found that polymers with acid groups form interpolymer complexes (IPCs) and miscible and immiscible IPC–PEG blends when blended with PEGs. PEGs formed IPCs with PAA and EcoA polymers in solutions and reach to saturation and turns to be blends of IPC and PEG polymer. PEGs in this work bleed out of the blends when its compositions reach to a degree of immiscibility. In the first range where blends are IPCs and in the third range where bleeding of PEG occurs, blends are not feasible for thermal energy storage applications. However, in the second range, the blends are potential materials for passive thermal energy storage applications.

A generic method for the determination of acrylamide in thermally processed foods.

Science.gov (United States)

Gökmen, Vural; Senyuva, Hamide Z

2006-07-07

A generic sample preparation method for the determination of acrylamide in foods was developed. The method entails extraction with methanol, purification with Carrez I and II solutions, evaporation and solvent change to water, and cleanup with Oasis HLB solid-phase extraction (SPE) cartridge. The final extract was analyzed by liquid chromatography-mass spectrometry (LC-MS) for quantitation. The chromatographic separation was performed on ODS-3 column using the isocratic mixture of 0.01 mM acetic acid in 0.2% aqueous solution of formic acid at a flow rate of 0.6 ml/min at 25 degrees C. The recoveries of acrylamide from potato chips, biscuits and coffee ranged between 92.8 and 101.5% with relative standard deviations of 4.1% or less. The limit of detection (LOD) and the limit of quantitation (LOQ) were 2 ng/g and 6 ng/g in the basis of signal to noise ratios of 3:1 and 9:1, respectively.

Effect of ono and di-protic Acid on the Characterization of 2-hydroxyethyl-methacrylate based hydrogels Prepared by gamma-radiation and its Application for Delivery

International Nuclear Information System (INIS)

El-Arnaouty, M.B.

2010-01-01

New co polymeric hydrogels based on 2-hydroxyethyl methacrylate P(HEMA), 2-hydroxyethyl methacrylate/acrylic acid P(HEMA/AAc) and 2-hydroxyethyl methacrylate /maleic acid P(HEMA/MA) copolymers were prepared by using 60 Co gamma-rays, in order to examine the potential use of these hydrogels in controlled drug release systems. The characterization of network structure of these hydrogels was studied by FTIR, SEM and the gel fraction yield. The thermal stability by DSC and TGA, kinetic swelling, and drug release behavior were also studied. It was shown that as increasing irradiation dose, the gel fraction yield was increase and the swelling percent was decrease. The parameters of equilibrium swelling, maximum swelling, initial swelling rate, swelling exponent (n), diffusion constant (K), diffusion coefficient (D) and penetration velocity (V) of the hydrogels were determined by studying the swelling behavior of the prepared hydrogels. Also, the swelling behavior of copolymer hydrogels in response to ph value of the external media was studied, it is noted that the highest swelling values were obtained at ph 6.8. The in vitro drug release behavior of these hydrogels was examined by quantification analysis using UV/VIS spectrophotometers. Colchicine is the drug which used in treatment of gout; it was loaded into dried hydrogels to investigate the stimuli-sensitive property at the specific ph. The release studies showed that the highest value of release was found to be at ph 6.8, such hydrogels could be used as drug delivery system

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.

In vivo imaging of the morphology and changes in pH along the gastrointestinal tract of Japanese medaka by photonic band-gap hydrogel microspheres

International Nuclear Information System (INIS)

Du, Xuemin; Lei, Ngai-Yu; Hu, Peng; Lei, Zhang; Ong, Daniel Hock-Chun; Ge, Xuewu; Zhang, Zhicheng; Lam, Michael Hon-Wah

2013-01-01

Graphical abstract: -- Highlights: •Fabrication of pH-responsive photonic colloidal crystalline microspheres. •Specific photonic band-gap responses occurred in the pH range of 4–5. •Remarkably low in vivo toxicity to Japanese medaka (Oryzia latipes). •In vivo imaging of the morphology and pH along GI tract of Japanese medaka. •Demonstrates bio-imaging potentials of stimuli-responsive photonic materials. -- Abstract: Colloidal crystalline microspheres with photonic band-gap properties responsive to media pH have been developed for in vivo imaging purposes. These colloidal crystalline microspheres were constructed from monodispersed core–shell nano-size particles with poly(styrene-co-acrylic acid) (PS-co-PAA) cores and poly(acrylic acid-co-N-isopropylacrylamide) (PAA-co-PNIPAM) hydrogel shells cross-linked by N,N′-methylenebisacrylamide. A significant shift in the photonic band-gap properties of these colloidal crystalline microspheres was observed in the pH range of 4–5. This was caused by the discontinuous volume phase transition of the hydrogel coating, due to the protonation/deprotonation of its acrylic acid moieties, on the core–shell nano-sized particles within the microspheres. The in vivo imaging capability of these pH-responsive photonic microspheres was demonstrated on a test organism – Japanese medaka, Oryzia latipes – in which the morphology and change in pH along their gastrointestinal (GI) tracts were revealed under an ordinary optical microscope. This work illustrates the potential of stimuli-responsive photonic band-gap materials in tissue-/organ-level in vivo bio-imaging

Autonomously Self-Adhesive Hydrogels as Building Blocks for Additive Manufacturing.

Science.gov (United States)

Deng, Xudong; Attalla, Rana; Sadowski, Lukas P; Chen, Mengsu; Majcher, Michael J; Urosev, Ivan; Yin, Da-Chuan; Selvaganapathy, P Ravi; Filipe, Carlos D M; Hoare, Todd

2018-01-08

We report a simple method of preparing autonomous and rapid self-adhesive hydrogels and their use as building blocks for additive manufacturing of functional tissue scaffolds. Dynamic cross-linking between 2-aminophenylboronic acid-functionalized hyaluronic acid and poly(vinyl alcohol) yields hydrogels that recover their mechanical integrity within 1 min after cutting or shear under both neutral and acidic pH conditions. Incorporation of this hydrogel in an interpenetrating calcium-alginate network results in an interfacially stiffer but still rapidly self-adhesive hydrogel that can be assembled into hollow perfusion channels by simple contact additive manufacturing within minutes. Such channels withstand fluid perfusion while retaining their dimensions and support endothelial cell growth and proliferation, providing a simple and modular route to produce customized cell scaffolds.

Novel Nano composite Optical Plastics: Dispersion of Titanium in Polyacrylates

International Nuclear Information System (INIS)

Suri, G.; Tyagi, M.; Seshadri, G.; Khandal, R.K.; Verma, G.L.

2010-01-01

Polyacrylates have become the preferred materials for optical applications replacing the conventionally used glass due to their superior optical clarity. The major disadvantage with polyacrylates is their low (1.40-1.50) refractive index besides their poor impact resistance. The improvements in refractive index as well as mechanical properties can be achieved by way of incorporation of metals or metal compounds in the matrix. A novel methodology for the incorporation of high refractive index metals into low refractive index polymeric materials to improve the refractive index and impact resistance of the latter has been developed. With the in-situ formation of nanoparticles of TiO 2 , the refractive index of polyacrylates improved from 1.45 to 1.53 and the Abbe number increased from 40 to 57. One of the interesting dimension of this study pertains to the possibility of tailor-making of the two key optical properties of materials by way of varying the amount of TiO 2 being formed in-situ. Thermal stability and impact resistance of nano dispersed (4.3% by wt. of Ti) polyacrylates are found to be better than the neat polyacrylates. Moreover, TiO 2 -containing polyacrylate is of light weight. TEM, SEM, and IR analysis confirms the in-situ formation of nanoparticles of TiO 2 . Gamma irradiation has been used as an eco-friendly technique for polymerization. The developed compositions can be cast polymerized into clear and bubble free material for optical applications.

A polycarboxylic/amino functionalized hyaluronic acid derivative for the production of pH sensible hydrogels in the prevention of bacterial adhesion on biomedical surfaces.

Science.gov (United States)

Palumbo, Fabio Salvatore; Bavuso Volpe, Antonella; Cusimano, Maria Grazia; Pitarresi, Giovanna; Giammona, Gaetano; Schillaci, Domenico

2015-01-15

A graft copolymer derivative of hyaluronic acid bearing pendant amino and short polymethacrylate portions (HA-EDA-BMP-MANa) has been employed for the production of a pH sensible vancomycin releasing hydrogel and studied in vitro to test its potential anti adhesive property against Staphylococcus aureus colonization. The copolymer obtained through atom transfer radical polymerization bears chargeable (carboxyl and amino groups) portions and it could be formulated as a hydrogel at a concentration of 10%w/v. The HA-EDA-BMP-MANa hydrogels, produced at three different pH values (5, 6 and 7, respectively), were formulated with or without the addition of vancomycin (2%w/v). The vancomycin release profiles were detected and related to the starting hydrogel pH values, demonstrating that the systems were able to sustain the release of drug for more than 48 h. S. aureus adhesion tests were performed on glass culture plates and hydroxyapatite doped titanium surfaces, comparing the performances of HA-EDA-BMP-MANa hydrogel formulations (obtained with and without vancomycin) with similar formulations obtained using unmodified hyaluronic acid. The non fouling property of a selected HA-EDA-BMP-MANa hydrogel (without vancomycin) was also assayed with a BSA adsorption test. We found that the HA-EDA-BMP-MANa hydrogel even without vancomycin prevented bacterial adhesion on investigated surfaces. Copyright © 2014. Published by Elsevier B.V.

Molecular modeling studies of interactions between sodium polyacrylate polymer and calcite surface

Energy Technology Data Exchange (ETDEWEB)

Ylikantola, A. [University of Jyväskylä, Department of Chemistry, P.O. Box 35, University of Jyväskylä, FI-40014 (Finland); Linnanto, J., E-mail: juha.m.linnanto@gmail.com [University of Jyväskylä, Department of Chemistry, P.O. Box 35, University of Jyväskylä, FI-40014 (Finland); University of Tartu, Institute of Physics, Riia 142, EE-51014 Tartu (Estonia); Knuutinen, J.; Oravilahti, A. [University of Jyväskylä, Department of Chemistry, P.O. Box 35, University of Jyväskylä, FI-40014 (Finland); Toivakka, M. [Åbo Akademi University, Laboratory of Paper Coating and Converting and Center for Functional Materials, FI-20500 Turku/Åbo (Finland)

2013-07-01

The interactions between calcite pigment and sodium polyacrylate dispersing agent, widely used in papermaking as paper coating components, were investigated using classical force field and quantum chemical approaches. The objective was to understand interactions between the calcite surface and sodium polyacrylate polymer at 300 K using molecular dynamics simulations. A quantum mechanical ab initio Hartree–Fock method was also used to obtain detailed information about the sodium polyacrylate polymer structure. The effect of water molecules (moisture) on the interactions was also examined. Calculations showed that molecular weight, branching and the orientation of sodium polyacrylate polymers influence the interactions between the calcite surface and the polymer. The force field applied, and also water molecules, were found to have an impact on all systems studied. Ab initio Hartree–Fock calculations indicated that there are two types of coordination between sodium atoms and carboxylate groups of the sodium polyacrylate polymer, inter- and intra-carboxylate group coordination. In addition, ab initio Hartree–Fock calculations of the structure of the sodium polyacrylate polymer produced important information regarding interactions between the polymers and carboxylated styrene-butadiene latex particles.

Photothermal-modulated drug delivery and magnetic relaxation based on collagen/poly(γ-glutamic acid hydrogel

Directory of Open Access Journals (Sweden)

Cho SH

2017-03-01

Full Text Available Sun-Hee Cho,1,* Ahreum Kim,1,* Woojung Shin,2 Min Beom Heo,1 Hyun Jong Noh,1 Kwan Soo Hong,3,4 Jee-Hyun Cho,3,4 Yong Taik Lim1,2 1SKKU Advanced Institute of Nanotechnology (SAINT, 2School of Chemical Engineering, Sungkyunkwan University, Suwon, 3Bioimaging Research Team, Korea Basic Science Institute, Cheongju, 4Immunotherapy Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea *These authors contributed equally to this work Abstract: Injectable and stimuli-responsive hydrogels have attracted attention in molecular imaging and drug delivery because encapsulated diagnostic or therapeutic components in the hydrogel can be used to image or change the microenvironment of the injection site by controlling various stimuli such as enzymes, temperature, pH, and photonic energy. In this study, we developed a novel injectable and photoresponsive composite hydrogel composed of anticancer drugs, imaging contrast agents, bio-derived collagen, and multifaceted anionic polypeptide, poly (γ-glutamic acid (γ-PGA. By the introduction of γ-PGA, the intrinsic temperature-dependent phase transition behavior of collagen was modified to a low viscous sol state at room temperature and nonflowing gel state around body temperature. The modified temperature-dependent phase transition behavior of collagen/γ-PGA hydrogels was also evaluated after loading of near-infrared (NIR fluorophore, indocyanine green (ICG, which could transform absorbed NIR photonic energy into thermal energy. By taking advantage of the abundant carboxylate groups in γ-PGA, cationic-charged doxorubicin (Dox and hydrophobic MnFe2O4 magnetic nanoparticles were also incorporated successfully into the collagen/γ-PGA hydrogels. By illumination of NIR light on the collagen/γ-PGA/Dox/ICG/MnFe2O4 hydrogels, the release kinetics of Dox and magnetic relaxation of MnFe2O4 nanoparticles could be modulated. The experimental results suggest that

Nanocomposites of Polyacrylic Acid Nanogels and Biodegradable Polyhydroxybutyrate for Bone Regeneration and Drug Delivery

Directory of Open Access Journals (Sweden)

Mikael Larsson

2014-01-01

Full Text Available Biodegradable cell scaffolds and local drug delivery to stimulate cell response are currently receiving much scientific attention. Here we present a nanocomposite that combines biodegradation with controlled release of lithium, which is known to enhance bone growth. Nanogels of lithium neutralized polyacrylic acid were synthesized by microemulsion-templated polymerization and were incorporated into a biodegradable polyhydroxybutyrate (PHB matrix. Nanogel size was characterized using dynamic light scattering, and the nanocomposites were characterized with regard to structure using scanning electron microscopy, mechanical properties using tensile testing, permeability using tritiated water, and lithium release in PBS using a lithium specific electrode. The nanogels were well dispersed in the composites and the mechanical properties were good, with a decrease in elastic modulus being compensated by increased tolerance to strain in the wet state. Approximately half of the lithium was released over about three hours, with the remaining fraction being trapped in the PHB for subsequent slow release during biodegradation. The prepared nanocomposites seem promising for use as dual functional scaffolds for bone regeneration. Here lithium ions were chosen as model drug, but the nanogels could potentially act as carriers for larger and more complex drugs, possibly while still carrying lithium.

Efficient removal of malachite green dye using biodegradable graft copolymer derived from amylopectin and poly(acrylic acid).

Science.gov (United States)

Sarkar, Amit Kumar; Pal, Aniruddha; Ghorai, Soumitra; Mandre, N R; Pal, Sagar

2014-10-13

This article reports on the application of a high performance biodegradable adsorbent based on amylopectin and poly(acrylic acid) (AP-g-PAA) for removal of toxic malachite green dye (MG) from aqueous solution. The graft copolymer has been synthesized and characterized using various techniques including FTIR, GPC, SEM and XRD analyses. Biodegradation study suggests that the co-polymer is biodegradable in nature. The adsorbent shows excellent potential (Qmax, 352.11 mg g(-1); 99.05% of MG has been removed within 30 min) for removal of MG from aqueous solution. It has been observed that point to zero charge (pzc) of graft copolymer plays significant role in adsorption efficacy. The adsorption kinetics and isotherm follow pseudo-second order and Langmuir isotherm models, respectively. Thermodynamics parameters suggest that the process of dye uptake is spontaneous. Finally desorption study shows excellent regeneration efficiency of adsorbent. Copyright © 2014 Elsevier Ltd. All rights reserved.

Reduction of Saltiness and Acrylamide Levels in Palm Sugar-Like Flavouring through Buffer Modification and the Addition of Calcium Chloride

Directory of Open Access Journals (Sweden)

Wan Aida Wan Mustapha

2013-06-01

Full Text Available Palm sugar-like flavouring (PSLF is a type of flavour product that is formed by heating amino acids and sugar under specific heating conditions. Unfortunately, PSLF has a salty taste and contains high amounts of acrylamide. Hence, the objective of this research was to reduce saltiness and acrylamide without negatively affecting the aroma properties of PSLF. A decrease in the sodium phosphate (NaHPO4 buffer concentration from 0.20 to 0.02 M was found to reduce sodium to approximately 15% of the level found in original PSLF. A further decrease (~25% in the sodium content was achieved by removing monobasic sodium phosphate (NaH2PO4 from the buffer system. Meanwhile, the addition of CaCl2 at 20–40 mg/L reduced the acrylamide content in PSLF by as much as 58%. A CaCl2 concentration of 20 mg/mL was most favourable as it most efficiently suppressed acrylamide formation while providing an acceptably high flavour yield in PSLF. In view of the high acrylamide content in PSLF, additional work is necessary to further reduce the amount of acrylamide by controlling the asparagine concentration in the precursor mixture.

Reduction of saltiness and acrylamide levels in palm sugar-like flavouring through buffer modification and the addition of calcium chloride.

Science.gov (United States)

Tan, Phui Yee; Tan, Chin Ping; Abas, Faridah; Ho, Chun Wai; Mustapha, Wan Aida Wan

2013-06-10

Palm sugar-like flavouring (PSLF) is a type of flavour product that is formed by heating amino acids and sugar under specific heating conditions. Unfortunately, PSLF has a salty taste and contains high amounts of acrylamide. Hence, the objective of this research was to reduce saltiness and acrylamide without negatively affecting the aroma properties of PSLF. A decrease in the sodium phosphate (NaHPO₄) buffer concentration from 0.20 to 0.02 M was found to reduce sodium to approximately 15% of the level found in original PSLF. A further decrease (~25%) in the sodium content was achieved by removing monobasic sodium phosphate (NaH₂PO₄) from the buffer system. Meanwhile, the addition of CaCl₂ at 20-40 mg/L reduced the acrylamide content in PSLF by as much as 58%. A CaCl₂ concentration of 20 mg/mL was most favourable as it most efficiently suppressed acrylamide formation while providing an acceptably high flavour yield in PSLF. In view of the high acrylamide content in PSLF, additional work is necessary to further reduce the amount of acrylamide by controlling the asparagine concentration in the precursor mixture.

The Effect of Chondroitin Sulphate and Hyaluronic Acid on Chondrocytes Cultured within a Fibrin-Alginate Hydrogel

Directory of Open Access Journals (Sweden)

Christopher J. Little

2014-09-01

Full Text Available Osteoarthritis is a painful degenerative joint disease that could be better managed if tissue engineers can develop methods to create long-term engineered articular cartilage tissue substitutes. Many of the tissue engineered cartilage constructs currently available lack the chemical stimuli and cell-friendly environment that promote the matrix accumulation and cell proliferation needed for use in joint cartilage repair. The goal of this research was to test the efficacy of using a fibrin-alginate hydrogel containing hyaluronic acid (HA and/or chondroitin sulphate (CS supplements for chondrocyte culture. Neonatal porcine chondrocytes cultured in fibrin-alginate hydrogels retained their phenotype better than chondrocytes cultured in monolayer, as evidenced by analysis of their relative expression of type II versus type I collagen mRNA transcripts. HA or CS supplementation of the hydrogels increased matrix glycosaminoglycan (GAG production during the first week of culture. However, the effects of these supplements on matrix accumulation were not additive and were no longer observed after two weeks of culture. Supplementation of the hydrogels with CS or a combination of both CS and HA increased the chondrocyte cell population after two weeks of culture. Statistical analysis indicated that the HA and CS treatment effects on chondrocyte numbers may be additive. This research suggests that supplementation with CS and/or HA has positive effects on cartilage matrix production and chondrocyte proliferation in three-dimensional (3D fibrin-alginate hydrogels.

Methods and compositions for treating low temperature subterranean well formations

Energy Technology Data Exchange (ETDEWEB)

Chatterji, J.

1979-08-21

An aqueous composition is described for treating subterranean formations having temperatures of up to 120 F. The aqueous composition consists of water, a water-soluble organic gelling agent, an oxidizing agent to supply free radicals, and a reducing agent to accelerate the generation of free radicals. Reducing agents are water-soluble metal salts of the halides, sulfates, nitrates or mixtures thereof. Oxidizing agents are water-soluble peroxides, persulfates or mixtures thereof. Gelling agents may be sodium polyacrylate, polyacrylic acid, polysodium-2-acrylamide-3-propylsulfonate polyacrylamides or polymetharylamides that have been hydrolyzed from 0 to 70% and neturalized with ammonium or alkali metal hydroxides; or gums such as guar, locust bean, taaga tragacanth, hydroxyethyl guar, hydroxy-propyl guar, carboxymethyl guar or mixtures thereof. 22 claims.

Acrylamide Mitigation Procedures in Fried Potatoes

DEFF Research Database (Denmark)

Pedreschi, Franco; Kaack, Karl; Granby, Kit

2008-01-01

frying, whereas acrylamide content was determined in the fried potato chips and French fries French fries. Blanching reduced in potato chips on average 76 percent and 68 percent of the glucose and asparagine content compared to the control. Potato slices blanched at 50 degrees C for 70 minutes......) of 0.79 and 0.83, respectively) with French fry acrylamide content....

PVA/atapulgite hydrogels; Hidrogeis de PVA/atapulgita

Energy Technology Data Exchange (ETDEWEB)