@article { ISI:000228080800024, title = {Swelling behavior and diffusion studies of high-water-retaining acrylamide/potassium methacrylate hydrogels}, journal = {Journal of Applied Polymer Science}, volume = {96}, number = {4}, year = {2005}, month = {MAY}, pages = {1153-1164}, publisher = {JOHN WILEY \& SONS INC}, type = {Article}, address = {111 RIVER ST, HOBOKEN, NJ 07030 USA}, abstract = {

Poly(acrylamide-co-potassium methacrylate) hydrogels were prepared by free-radical simultaneous polymerization with aqueous solutions of acrylamide (AAm) and potassium methacrylate (KMA) with a redox initiator. The copolymerization was performed with eight different compositions of KMA at a fixed concentration of oil-soluble crosslinkers, including 1,4-butanediol diacrylate and ethylene glycol dimethacrylate (EGDMA). For every composition of AAm/KMA copolymer, the percentage swelling, swelling equilibrium, and diffusion characteristics were investigated. The copolymers were further studied for deswelling properties. The power law relationships of the hydrogels were evaluated for variation in terms of saline concentration. The AAm/KMA copolymers were confirmed by IR spectroscopy. Thermal studies of hydrogels were performed with differential scanning calorimetry and thermogravimetric analysis. EGDMA was found to be a better crosslinker for obtaining higher swelling and deswelling properties for the AAm/KMA hydrogels. (c) 2005 Wiley Periodicals, Inc.

}, keywords = {Diffusion, hydrogels, swelling}, issn = {0021-8995}, doi = {10.1002/app.21565}, author = {Mohan, Y. M. and Murthy, P. S. K. and Rao, K. M. and Sreeramulu, J. and Raju, K. M.} } @article { ISI:000293741800076, title = {Magnetic and electric responsive hydrogel-magnetic nanocomposites for drug-delivery application}, journal = {Journal of Applied Polymer Science}, volume = {122}, number = {2}, year = {2011}, month = {OCT}, pages = {1364-1375}, publisher = {WILEY-BLACKWELL}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

Magnetic and electrically responsive hydrogel networks were developed for drug-delivery applications. The hydrogel matrices were synthesized by the polymerization of acrylamide monomer in the presence of carboxymethylcellulose (CMC) or methylcellulose (MC) with N,N-methylenebisacrylamide, a crosslinker with the redox initiating system ammonium persulfate/tetramethylethylenediamine. The magnetic nanoparticles were generated throughout these hydrogel matrices by an in situ method by the incorporation of iron ions and their subsequent reduction with ammonia. A series of hydrogel-magnetic nanocomposites (HGMNCs) were developed with various CMC and MC compositions. The synthesized HGMNCs were characterized with spectral (Fourier transform infrared and ultraviolet-visible spectroscopy), X-ray diffraction, thermal, and microscopy methods. These HGMNCs contained iron oxide (Fe3O4) nanoparticles with an average particle size of about 22 nm, as observed by transmission electron microscopy. The dielectrical properties of the pure hydrogel (HG); the hydrogel loaded with iron ions, or the hydrogel iron-ion composite (HGIC); and the HGMNCs were measured. These results suggest that HGMNCs exhibited higher dielectric constants compared to HG and HGICs. The curcumin loading and release characteristics were also measured for HG, HGIC, and HGMNC systems. These data revealed that there was a sustained release of curcumin from HGMNCs because of the presence of magnetic nanoparticles in the hydrogel networks. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 1364-1375, 2011

}, keywords = {hydrogels, magnetic polymers, Nanocomposites, nanoparticle, nanotechnology}, issn = {0021-8995}, doi = {10.1002/app.34016}, author = {Reddy, N. Narayana and Mohan, Y. Murali and Varaprasad, K. and Ravindra, S. and Joy, Pattayil Alias and Raju, K. Mohana} } @article { ISI:000312472000040, title = {Gold nanoparticle embedded hydrogel matrices as catalysts: better dispersibility of nanoparticles in the gel matrix upon addition of N-bromosuccinimide leading to increased catalytic efficiency}, journal = {Colloids and Surfaces A-Physicochemical and Engineering Aspects}, volume = {414}, year = {2012}, month = {NOV}, pages = {296-301}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple and convenient method for generating and immobilizing gold NPs into polyethylene glycol-polyurethane (PEGPU) matrices is presented. The gold NP immobilized PEGPU (Au NP-PEGPU) hydrogel matrices are easy to handle and can be used as catalysts. The efficiency, reusability and durability of the Au NP-PEGPU catalyst matrices were investigated using the reduction of 4-nitroaniline (4NA) to p-phenylenediamine (p-PDA) by sodium borohydride in the presence of the catalyst as a test reaction. The Au NPs in the PEGPU matrix got aggregated after 3 cycles of catalysis but dispersion could be regenerated by the addition of N-bromosuccinimide (NBS). After this regeneration process the Au NPs-PEGPU matrix showed excellent efficiency without any aggregation, leaching or degradation. The reusability of the catalyst for 28 cycles yielding a total turnover number of 3220 and turn over frequency of 0.152 s(-1) is demonstrated. (C) 2012 Elsevier B.V. All rights reserved.

}, keywords = {catalysis, hydrogels, Immobilization, Nanoparticles, Turn over numbers}, issn = {0927-7757}, doi = {10.1016/j.colsurfa.2012.08.026}, author = {Ramtenki, Vilas and Anumon, V. D. and Badiger, Manohar V. and Bhagavatula L. V. Prasad} } @article { ISI:000335434600004, title = {Thermoresponsive and biodegradable dextran based microgels: synthesis and structural investigation}, journal = {Macromolecular Symposia}, volume = {329}, number = {1}, year = {2013}, note = {Polymer Networks Conference (PNG), WY, AUG 12-16, 2012}, month = {JUL}, pages = {27-34}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Nanostructured objects, often ranging from hundreds of nanometers to few microns, support a number of functions directly linked to their structural features. They are, or they will be, protagonists in biomedical applications where miniaturized activities are required. These include the interface with living systems as tissues and cells, where targeted release of drug molecules occurs, or molecular imaging methods monitoring the drug trafficking in specific cell districts. The potentials of such devices, far to be fully understood, will be assessed only when a close correlation of their functions with their structure will be established. In this contribution we present a dextran based microdevice responsive to temperature and biodegradable. Both thermoresponsivity and biodegradability are of relevance for the potential use as drug carrier and controlled release device. The temperature behaviour, overall structure and internal architectures have been addressed with different methods.

}, keywords = {Biomaterials, colloids, dynamic light scattering, hydrogels, p(NiPAAm)}, issn = {1022-1360}, doi = {10.1002/masy.201300009}, author = {Ghugare, Shivkumar V. and Chiessi, Ester and Sakai, Victoria Garcia and Telling, Mark T. F. and Wadgaonkar, Prakash P. and Paradossi, Gaio} } @article { ISI:000349401200010, title = {Porous poly(ethylene glycol)-polyurethane hydrogels as potential biomaterials}, journal = {Polymer International}, volume = {64}, number = {3}, year = {2015}, month = {MAR}, pages = {397-404}, publisher = {WILEY-BLACKWELL}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, abstract = {

We report the synthesis of porous poly(ethylene glycol)-polyurethane (PEG-PU) hydrogels using PEG-4000 as a soft segment and 4,4-methylenebis(cyclohexylisocyanate) as a hard segment. The degree of swelling in the hydrogels could be controlled by varying the amount of crosslinking agent, namely 1,2,6-hexanetriol. Structural characterization of the hydrogels was performed using solid-state C-13 NMR and Fourier transform infrared spectroscopy. Wide-angle X-ray diffraction studies revealed the existence of crystalline domains of PEG and small-angle X-ray scattering studies showed the presence of lamellar microstructures. For generating a porous structure in the hydrogels, cryogenic treatment with lyophilization was used. Scanning electron microscopy and three-dimensional micro-computed tomography imaging of the hydrogels indicated the presence of interconnected pores. The mechanical strength of the hydrogels and xerogels was measured using dynamic mechanical analysis. The observed dynamic storage moduli (E) for the equilibrium swollen and dry gels were found to be 0.15 and 4.2 MPa, respectively. Interestingly, the porous PEG-PU xerogel also showed E of 5.6 MPa indicating a similar mechanical strength upon incorporating porosity into the gel matrix. Finally, preliminary cytocompatibility studies showed the ability of cells to proliferate in the hydrogels. These gels show promise for applications as scaffolds and implants in tissue engineering. (c) 2014 Society of Chemical Industry

}, keywords = {hydrogels, permeability, poly(ethylene glycol), polyurethane, porosity}, issn = {0959-8103}, doi = {10.1002/pi.4802}, author = {Divakaran, Anumon V. and Torris, Arun A. T. and Lele, Ashish K. and Badiger, Manohar V.} } @article {43806, title = { Design and development of trivalent aluminum ions induced self healing polyacrylic acid novel hydrogels}, journal = {POLYMER}, volume = {126}, year = {2017}, month = {SEP}, pages = { 196-205}, type = {Journal Article}, chapter = {196-205}, abstract = {

Development of ionically crosslinked superabsorbent polyacrylic acid (PAA) self-healing hydrogels using trivalent aluminum ions was investigated. The PAA hydrogels exhibited excellent self-healing behavior depending on the amount of the aluminum within the matrix. The migration of these ions within the polymer matrix was responsible for the physical crosslinking of the hydrogel and the origin of self healing ability. The PAA-Al hydrogels were insoluble in water and exhibited significantly high degree of swelling (similar to 4000\%). Hydrogel also exhibited good mechanical properties with high level of elongation. Excellent self-healing efficiency was observed under dynamic as well as oscillatory Theological measurements. The presence of Al ions within PAA hydrogel facilitated the self-healing ability because of the ionic interaction in these gels which plays the key role of dynamic reversible sacrificial bonds which reforms upon reversal of the deformative force. (C) 2017 Elsevier Ltd. All rights reserved.

}, keywords = {Aluminum chloride, Behavior, Complex, Composite, crosslinking, Delivery, High-Mechanical Strength, hydrogels, Network, Polyacrylic acid, Polymeric Materials, Self-healing, swelling, Tough; pH}, issn = {0032-3861}, doi = {10.1016/j.polymer.2017.08.045}, author = {Anjum, Sadiya and Gurave, Pramod and Badiger, Manohar V. and Tiwari, Neha and Gupta, Bhuvanesh} } @article {46705, title = {Injectabledextran-fluorenylmethoxycarbonylphenylalanine composite hydrogels with improved mechanical properties}, journal = {Polymer International}, volume = {70}, year = {2021}, month = {FEB}, pages = {222-229}, type = {Article}, abstract = {

Low molecular weight hydrogels are recently gaining importance owing to their applications in material sciences and biology. A new class of composite hydrogel was developed using polysaccharides such as dextran and fluorenylmethoxycarbonyl phenylalanine (FmocF) in a phosphate buffer. The molecular weight and concentration of the dextran were varied to obtain rigid but injectable hydrogels without using other crosslinking agents. From the different molecular weights of dextran studied (5k, 40k and 70k), a combination of FmocF (0.6\% w/v) and dextran 40k (0.012\% w/v) composite gels yielded a maximum value of storage modulus of approximately 1500 Pa, which is 3.5 times higher than the storage modulus of pure FmocF gels. Scanning electron microscopy of FmocF/dextran composite gels revealed highly tangled fibrous structures with dense branches and lower fiber diameter compared to pure FmocF gels. The high-intensity hydrogen-bonded N-H peak in the infrared spectra showed enhanced hydrogen bonding in FmocF/dextran composite gels compared to pure FmocF gels. The dextran acts as an impurity in the process of fibrillation, leading to a crystallographic mismatch, and densely packed thin fibers are formed. These gels exhibited gel to sol and sol to gel conversion with temperature or external stress and showed injectable behavior. (c) 2020 Society of Industrial Chemistry

}, keywords = {Dextran, Fmoc-Phe, hydrogels, injectable gels, Rheology}, issn = {0959-8103}, doi = {10.1002/pi.6118, Early Access Date = SEP 2020}, author = {Abraham, Jancy N. and Joseph, Seena and Trivedi, Rishabh and Karle, Mrunal} }