Hydrogels characterization

Pal K, Banthia AK, Majumdar DR. Polymeric hydrogels characterization and biomedical applications a mini review. Des Monomers Polym 2009 12 197-220. 

Pal, K., Banthia, A. K., and Majumdar, D. K. 2009. Polymeric hydrogels Characterization and biomedical applications—A mini review. Des. Monomers Polym. 12 197. 

Medicine. The polymethacrylates have been used for many years in the manufacture of dentures, teeth, denture bases, and filling materials (116,117) (see Dental materials). In the orthodontics market, methacrylates have found acceptance as sealants, or pit and fissure resin sealants which are painted over teeth and act as a barrier to tooth decay. The dimensional behavior of curing bone-cement masses has been reported (118), as has the characterization of the microstmcture of a cold-cured acryUc resin (119). Polymethacrylates are used to prepare both soft and hard contact lenses (120,121). Hydrogels based on 2-hydroxyethyl methacrylate are used in soft contact lenses and other biomedical appHcations (122,123) (see Contactlenses). 

Hydrogels are water-containing polymers, hydrophilic in nature, yet insoluble. In water, these polymers swell to an equiUbrium volume and maintain thek shape. The hydrophilicity of hydrogel is a result of the presence of functional groups such as —NH2, —OH, —COOH, —CONH2, —CONH—, —SO H, etc. The insolubihty and stabiUty of hydrogels are caused by the presence of a three-dimensional network. The scope, preparation, and characterization of hydrogels has been reviewed (107). 

However, it yields dynamic modulus. Some other techniques were also used to characterize hydrogels, for example, viscoelastic measurements [28, 30, 31] and swelling equilibrium [20]. 

Therefore, the SAH swelling and deswelling rates can be quantitatively characterized by the time t which for a given hydrogel type is determined mainly by the gel particle size. The gel instability, both mechanical and thermodynamical, constitutes an additional complication [128 -130]. 

Al-Assaf, S. Phillips, G.O. Aoki, H. Sasaki, Y. (2007). Characterization and properties of Acacia Senegal (L.) Willd. var. Senegal with enhanced properties (Acacia (sen) SUPER GUM ) Part 1-Controlled maturation of Acacia Senegal var. Senegal to increase viscoelasticity, produce a hydrogel form and convert a poor into a good emulsifier Food Hydrocollotds, Vol.21, No.3, (May 2007), pp. 319-328, ISSN 0268-005X. 

Chul, M Phillips, R McCarthy, M, Measurement of the Porous Microstructure of Hydrogels by Nuclear Magnetic Resonance, Journal of Colloid and Interface Science 174, 336, 1995. Cohen, Y Ramon, O Kopeknan, IJ Mizrahi, S, Characterization of Inhomogeneous Polyacrylamide Hydrogels, Journal of Polymer Science Part B Polymer Physics 30, 1055, 1992. Cohen Addad, JP, NMR and Statistical Structures of Gels. In The Physical Properties of Polymeric Gels Cohen Addad, JP, ed. Wiley Chichester, UK, 1996 39. 

PI Lee. Synthetic hydrogels for drug delivery Preparation, characterization and release characteristics. In DST Hsieh, ed. Controlled Release Systems Fabrication Technology, Vol II. Boca Raton, FL CRC Press, 1988, pp 83-110. 

NA Peppas, BD Barr-Howell. Characterization of the crosslinked structure of hydrogels. In NA Peppas, ed. Hydrogels in Medicine and Pharmacy, Vol. I Fundamentals. Boca Raton, FL CRC Press, 1986, pp 27-56. 

AP Sassi, HW Blanch, JM Prausnitz. Characterization of size-exclusion effects in highly swollen hydrogels Correlation and prediction. J Appl Polym Sci 59 1337-1346, 1996. 

Even though, structure and dynamics are most important to characterize hydrogels, protein fibrils, and membrane proteins, they cannot be simultaneously determined. We emphasize here the importance of the dynamic aspect mainly available from NMR measurements at ambient temperature, even though structural data can be obtained more easily at lower temperatures under suppressed dynamics. 

We have emphasized here that the dynamic aspects of NMR studies are crucially important for structurally or dynamically heterogeneous systems such as synthetic or natural hydrogels, protein fibrils and membrane proteins. This is in order to characterize their unique chemical, physical and biological properties in terms of a variety of fluctuation frequencies, including high (> 108 Hz) or intermediate (104-105 Hz) frequency fluctuations. It turns out that the presence of the high-frequency motions, which are readily evaluated by comparative CPMAS and DDMAS studies, is... 

Prokop, A., Kozlov, E., Carlesso, G. and Davidsen, ]. M. Hydrogel-Based Colloidal Polymeric System for Protein and Drug Delivery Physical and Chemical Characterization, Permeability Control and Applications. Vol. 160, pp. 119-174. 

Na K, Park KH, Kim SW et al (2000) Self-assembled hydrogel nanoparticles from curdlan derivatives characterization, anti-cancer drug release and interaction with a hepatoma cell line (HepG2). J Control Release 69 225-236... 

Lutolf MP, Hubbell JA (2003) Synthesis and physicochemical characterization of end-linked poly(ethylene glycol)-co-peptide hydrogels formed by michael-type addition. Biomacromolecules 4 713-722... 

Nam KW, Watanabe J, Ishihara K (2002) Characterization of the spontaneously forming hydrogels composed of water-soluble phospholipid polymers. Biomacromolecules 3 100-105... 

Chou Al, Nicoll SB (2009) Characterization of photocrosslinked alginate hydrogels for nucleus pulposus cell encapsulation. J Biomed Mater Res A 91(1) 187-194... 

Reza AT, Nicoll SB (2009) Characterization of novel photocrosslinked carboxymethyl-cellulose hydrogels for encapsulation of nucleus pulposus cells. Acta Biomater 6(1) 179-186... 

Characterization of Hydrogel Films. Mechanical testing was conducted in buffered saline on an Instron instrument, according to the modified ASTM D-1708 (tensile) and D-1938 (tear) and were reported in g/mm2 for modulus and g/mm for tear strength. The water contents and the amount of extractables were measured gravimetr ica1ly. 

Here n5 and nm are the refractive indices of the microsphere and ambient medium, respectively, and R is the microsphere radius. To determine An and t from this equation, it is sufficient to measure AA for two wavelength, ly1 and A. In Ref. 36, this was done for A[ = 760 nm and A[ = 1,310nm. As the result the authors optically characterized a hydrogel nanolayer with 110-nm thickness and an extremely small excess refractive index of 0.0012, which was formed in situ in an aqueous environment. 

In order to achieve the firm fixation of the artificial cornea to host tissues, composites of collagen-immobilized poly(vinyl alcohol) hydrogel with hydroxyapatite were synthesized by a hydroxyapatite particles kneading method. The preparation method, characterization, and the results of corneal cell adhesion and proliferation on the composite material were studied. PVA-COL-HAp composites were successfully synthesized. A micro-porous structure of the PVA-COL-HAp could be introduced by hydrochloric acid treatment and the porosity could be controlled by the pH of the hydrochloric acid solution, the treatment time, and the crystallinity of the HAp particles. Chick embryonic keratocyto-like cells were well attached and proliferated on the PVA-COL-HAp composites. This material showed potential for keratoprosthesis application. Further study such as a long-term animal study is now required [241]. 

M. Rinja, S. Patachia. Synthesis, characterization and applications of PVA hydrogels. 

El Sherbiny IM, Lins RJ, Abdel-Bary EM, Harding DRK (2005) Preparation, characterization, swelling and in vitro drug release behaviour of poly [N-acryloylglycine-chitosan interpoly-meric pH and thermally-responsive hydrogels. European Polymer Journal 41 2584-2591. 

There are 22 chapters in the book and they cover the most important aspects of polymers as drugs, prodrugs, dmg delivery systems, and in situ prostheses. The major features promulgated are synthesis, derivatization, degradation, characterization, application, and evaluation techniques as well as new biodegradable materials, assemblies, hydrogels, telechelic polymers, derivatized polysaccharides, micro- and nanoparticles, mimetic... 

Brazel, C. S. and Peppas, N. A. Synthesis and characterization of thermo- and chemomechanically responsive poly(A-isopropylacrylamide-co-methacryhc acid) hydrogels. Macromolecules 1995, 28, 8016-8020. 

Brondsted, H., and Kopecek, J., Hydrogels for site-specific oral drug delivery synthesis and characterization. Biomaterials, 12 584-592 (1991). 

Chiu, H.C., Hsiue, G.H., Lee, Y.P., and Huang, L.W., Synthesis and characterization of pH-sensitive dextran hydrogels as a potential colon-specific drug delivery system, J. Biomater. Sci. Polym. ed., 10 591-608 (1999). 

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