Biopolymer hydrogels

Kulicke, W.-M., and Nottelmann, H. (1989). Structure and swelling of some synthetic, semisynthetic, and biopolymer hydrogels. In Polymers in Aqueous Media, Glass, J. E. (Ed.), Advances in Chemistry 223, pp. 15-44. Am. Chem. Soc., Washington, DC. 

In a very different approach, a chitosan biopolymer hydrogel containing amino and hydroxy groups (68) has been efficiently employed for aldol and Knoevenagel reactions under biphasic conditions. The gel beads can be filtered and recycled for three consecutive runs, maintaining the same overall efficiency. 

Structure and Swelling of Some Synthetic, Semisynthetic, and Biopolymer Hydrogels... 

The water absorption capacity of some synthetic, semisynthetic, and biopolymer hydrogels was studied in distilled water. The swelling behavior in both water and salt solutions (M, . ..) was studied... 

Grassi, M. (1989) Design of Drug Delivery Systems Division in Biopolymer Hydrogels, University of Trieste. 

Aime, C. and Coradin, T. (2012) Nanocomposites from biopolymer hydrogels blueprints for white biotechnology and green materials chemistry. /. Polym. Sci B Polym. Phys.,... 

Jeng, L., Olsen, B.R., Spector, M. Engineering endostatin-expressing ceutilaginous constructs using injectable biopolymer hydrogels. Acta Biomater. 8, 2203-2212 (2012)... 

Partially deacetylated chitin, a cellulose-like biopolymer consisting predominantly of N-acetyl-D-glucosamine chains, in the form of films or crosslinked hydrogels has been used for the delivery of drugs (28,29). The suitability of chitin as a vehicle for the sustained release of drugs was examined using indomethacin and papaverine hydrochloride as model drugs (30). In vitro studies showed that over 80% of the indomethacin was released within 7 hr, whereas papaverine hydrochloride dissolved almost immediately. 

Rajagopal K, Ozbas B, Pochan DJ et al (2005) Self-assembled hydrogels from beta- hairpin peptides tuning responsiveness and bulk material properties by peptide design. Biopolymers 80 487 87... 

Branco M, Wagner N, Pochan D et al (2009) Release of model macromolecules from selfassembling peptide hydrogels for injectable delivery. Biopolymers 92 318-318... 

Biopolymers such as agarose hydrogel can also be used to immobilize HRP and to reduce oxygen, hydrogen peroxide and nitric oxide [231], For an HRP-agarose/EPG in a pH 7.0 PBS, a reduction peak at -0.30V was observed after addition of H2Q2. 

Lubricity. Outer-wall lubricity is particularly important for intravascular catheters, otherwise the endothelial layer of blood vessels is easily damaged by interventional insertion. Lubricity is usually acquired by coating with hydrogels or biopolymers. 

Hydrogel micro- and nanoparticles composed of biopolymer matrixes have gained a lot of attention in recent years due to their application in drug delivery and tissue engineering [10,14,45 17], The biopolymers used for these purposes are nontoxic,... 

To the best of our knowledge, only a few studies have attempted to prevent the calcification of HEMA-based hydrogels. It has been reported that introduction of carboxylate anions can either prevent or enhance calcification. Cemy et al. (21) found that copolymers of HEMA with 4 wt% methaciylic acid (MAAc) did not calcify under subcutaneous implantation in a rat for 14 months. A similar result was also observed after the implantation of HEMA/MAAc copolymers in the animal urinary tract (22). Other studies carried out in vitro showed that the presence of carboxylate anions significantly reduced the deposition of calcium phosphate (23) and calcium oxalate (24) on acrylic polymers and certain biopolymers. These findings obviously suggest an inhibitory effect of carboxylate anions on calcification. However, by contrast,... 

There have been a number of other papers on the hydration of biopolymers the effects of the degree of methylation of pectins on the proton relaxation times of water have been measured 50 l70 relaxation has been used to examine the hydration of bovine and caprine casein,51--54 and solid-state NMR combined with atomic force microscopy has been used to examine the influence of water on the nanomechanical behaviour of cutin.55 The effects of locust bean gum on water diffusion in sugar solutions has shown little effect,56 and the effects of gellan gum hydrogel structure on restricted diffusion has also been considered.57... 

Hydrogel Comparison. Figure 18 is a survey of the water absorption capacity for some of the synthetic, semisynthetic, and biopolymer gels. The values given refer to 1 g of dry material. For comparison, some types of gel are included in Figure 18 that were not mentioned in the previous discussion. 

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