Dextran hydrogels biocompatibility

Dextran is a biocompatible polymer used for the preparation of hydrogels. Dextran hydrogels can be obtained by several different approaches and they have received increased attention due to the variety of their biotechnological and biomedical applications. Dextran hydrogels have been frequently considered as a potential matrix system for colon-specific dehvery and/or controlled release (CR) of bioactive... 

A biodegradable and biocompatible dextran hydrogel system has been developed of which the degradation time can be tailored between 2 days and 3 months. This chapter shows that hydrogels based on crosslinked dextrans have unique properties as protein releasing matrices. Both the release pattern (first-order, zero-order or biphasic) as well as the duration of the release can be controlled by an appropriate selection of the characteristics and the geometry of the hydrogel. 

Figure 11.6 Dialysis capillary setup that could be used to employ the SWNT sensing system in vivo. The dextran-SWNT and Con A mixture is retained in the capillary while glucose is free to diffuse across the membrane. A biocompatible hydrogel, filled with VEGF, can be used to coat the capillary. Such a system could be implanted beneath the skin, with SWNT excitation from a laser photodiode and fluorescence detection from a CCD camera. Adapted with permission from Ref. 17.

Cadee JA, Van Luyn MJA, Brouwer LA, Plantinga JA, Van Wachem PB, De Groot CJ, Den Otter W, Hennink WE. In vivo biocompatibility of dextran-based hydrogels. J Biomed Mater Res 2000 50 397-404. 

Natural polymers have also been used as thermo-sensitive hydrogels, either on their own or in combination with other synthetic polymers. Popular natural polymers include chitosan, cellulose derivatives, dextran, xyloglucan and gelatin (Klouda and Mikos 2008). Chitosan is a polysaccharide derived from the shells of crustaceans and is produced by deacetylation of chitin, basically through the removal of the acetyl group using a concentrated NaOH solution (Fig. 11.5). The main advantage of chitosan for medical and pharmaceutical applications is its biocompatibility and inertness when in contact with human cells (Kumar et al. 

Journal of Biomedical Materials Research 50, No.3, 5th June 2000, p.397-404 IN VIVO BIOCOMPATIBILITY OF DEXTRAN-BASED HYDROGELS... 

Dextran-based hydrogels were produced by the polymerisation of aqueous solutions of methacrylated dextran or lactate-hydroxyethyl methacrylate-derivatised dextran and implanted subcutaneously in rats for up to 6 weeks. The effects of initial water content and degree of substitution of these hydrogels on tissue response were examined and the relationship between in vitro and in vivo degradation behaviour was investigated. The results obtained indicated that these hydrogels were biocompatible and could be potential candidates for drug delivery systems. 20 refs. 

Abed, A., Assoul, N., Ba, M., Derkaoui, S.M., Fortes, P., Louedec, L., FUaud, P., Bataille, I., Letourneur, D., Meddahi-Pelle, A., 2011. Influence of polysaccharide composition on the biocompatibility of pullulan/dextran-based hydrogels. J. Biomed. Mater. Res. Part A 96A, 535-542. 

Draye, J.P., Delaey, B., Van de Voorde, A., Van Den Bulcke, A., De Reu, B., Schacht, E. (1998) In Vitro and in Vivo Biocompatibility of Dextran Dialdehyde Cross-Linked Gelatin Hydrogel Films. Biomaterials, 19,1677-1687. 

Draye J P, Delaey B, Voorde A V D, Bulcke A V D, Rue B D, Schacht E (1998), In vitro and in vivo biocompatibility of dextran dialdehyde cross-linked gelatin hydrogel films , Biomaterials, 19, 1677-87. 

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