In situ forming IPN hydrogels of calcium alginate and dextran-HEMA for biomedical applications

Abstract

In situ forming hydrogels, which allow for the modulation of physico-chemical properties, and in which cell response can be tailored, are providing new opportunities for biomedical applications. Here, we describe interpenetrating polymer networks (IPNs) based on a physical network of calcium alginate (Alg-Ca), interpenetrated with a chemical one based on hydroxyethyl-methacrylate-derivatized dextran (dex-HEMA). IPNs with different concentration and degree of substitution of dex-HEMA were characterized and evaluated for protein release as well as for the behavior of embedded cells. The results demonstrated that the properties of the semi-IPNs, which are obtained by dissolution of dex-HEMA chains into the Alg-Ca hydrogels, would allow for injection of these hydrogels. Degradation times of the IPNs after photocross-linking could be tailored from 15 to 180 days by the concentration and the degree of substitution of dex-HEMA. Further, after an initial burst release, bovine serum albumin was gradually released from the IPNs over approximately 15 days. Encapsulation of expanded chondrocytes in the IPNs revealed that cells remained viable and, depending on the composition, were able to redifferentiate, as was demonstrated by the deposition of collagen type II. These results demonstrate that these IPNs are attractive materials for pharmaceutical and biomedical applications due to their tailorable mechanical and degradation characteristics, their release kinetics and biocompatibility.

Photochemical Production of Interpenetrating Polymer Networks; Simultaneous Initiation of Radical and Cationic Polymerization Reactions

“…Different examples can be given: acrylate/epoxide, (e.g., hexanediol diacrylate (HDDA)/3,4-epoxycyclohexylmethyl-3'4' epoxycyclohexyl carboxylate (EPOX)), trimethylolpropane triacrylate (TMPTA)/EPOX, TMPTA/diglycidyl ether of bisphenol A based epoxy resin EP, TMPTA/tri(ethylene glycol) divinyl ether (DVE-3), TMPTA/4-cyclo-hexane dimethanol divinyl ether (CHVE), fluorinated acrylate/epoxide, vinylether/acrylate, vinylether/maleate, vinylether/maleimide or oxetane/acrylate blends, (see e.g., in [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]) anthracene-labeled polystyrene/methyl methacrylate MMA/ethylene glycol dimethacrylate [36], polyisobutene/polystyrene [37], polyacrylate/polybenzoxazine [38], acrylic/liquid crystals [39,40], 2-hydroxyethyl methacrylate/N-vinyl-2-pyrrolidone [41], polyurethane/poly(2-hydroxyethyl methacrylate) [42], calcium alginate/dextran-HEMA [43].…”

Polímeros usados como sistemas de transporte de princípios ativos

“…Estes polímeros são hemocompatíveis e não sofrem acumulação em qualquer órgão após a administração [44] . Na literatura são encontradas várias utilizações de alginato de cálcio em sistemas de liberação modificada [45,46] . A velocidade de liberação do princípio ativo incorporado em micropartículas de alginato de sódio parece ser afetada pelo tipo de agente de reticulação utilizado no método de preparação [47] .…”

Calcium alginate/dextran methacrylate IPN beads as protecting carriers for protein delivery

“…In this case the combination of polymeric microspheres in hydrogel macro-systems allows to combine mild preparative conditions for protein entrapment (microspheres formation) and protein controlled release (the hydrogel being the rate controlling agent) [30][31][32][33]. In this context alginate microparticles represent a very useful vehicle, due to the easy and mild conditions needed for their preparation [34][35][36]. Within the above mentioned contest, we developed new particulate systems based on interpenetrating polymer network hydrogels obtained with alginate and dextran methacrylate derivative [36,37].…”

“…In this context alginate microparticles represent a very useful vehicle, due to the easy and mild conditions needed for their preparation [34][35][36]. Within the above mentioned contest, we developed new particulate systems based on interpenetrating polymer network hydrogels obtained with alginate and dextran methacrylate derivative [36,37]. Here the mechanical characterization and the release properties of these new drug delivery systems are reported with respect to a reference system based on plain alginate.…”