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In the present study, dextran-epichlorohydrin hydrogels were employed as carriers for the controlled release of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF). The hydrogels were synthesized from 50% (by weight) monomeric cross-linker, epichlorohydrin, containing dextran mixtures by intermolecular side-chain reaction of dextran-hydroxyl groups with epichlorohydrin-epoxy groups. The hydrogel disks of 3-mm diameter and 1.5-mm thickness have a high swelling capacity (EWC = 650%) and enough mechanical stability for the studies in vivo. Impregnation of EGF and bFGF into the dried hydrogels was carried out by use of phosphate buffered saline solution (PBS, pH = 7.4) containing 0.5 microg mL(-1) EGF and 0.1 microg mL(-1) bFGF, respectively. The in vitro release of growth factors was detected by fluorescence spectroscopy. The prolonged release of EGF is continued up to the 14th day, in comparison with a 26-day release of bFGF. The in vivo studies were realized with subcutaneously implanted hydrogels in Wistar albino rats. The rate of neovascularization was analyzed statistically using one-way analysis of significance with EGF and bFGF incorporated hydrogels. In conclusion, dextran-epichlorohydrin hydrogels were shown to be an alternative delivery system for the release of growth factors.

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Jack bean (Canavalia ensiformis) is the source of interesting proteins that contribute to modern biochemistry, and urease is the primary of these proteins. Owing to its role and occurrence in nature, urease has become a part of extensive studies. In this study, jack bean urease (JBU) was purified by immobilized metal affinity chromatography using Cu(2+) chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-histidine methyl ester) [PHEMAH-Cu(2+)]-based cryogels. PHEMAH-Cu(2+) cryogel was synthesized and characterized for swelling degree, morphology (by SEM), N-methacryloyl-(L)-histidine methyl ester and Cu(2+) incorporation (by elemental analysis and atomic absorption spectrophotometry). The binding of JBU to PHEMAH-Cu(2+) cryogel was optimized by examining the effect of pH, flow rate and JBU concentration on binding. The maximal binding of JBU was 23.2 mg/dry gram of adsorbent. The maximal binding of JBU extracted from jack bean meal was 67.8 mg/dry gram of adsorbent. The elution of JBU from cryogel column was accomplished by 1.0 M NaCl in 20 mM phosphate buffer (pH 8.0). Molecular weight and purity of JBU from jack bean meal was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was observed that JBU could be repeatedly bound and eluted from (PHEMAH)-Cu(2+) cryogel with less than 10% loss in column capacity.