Non-cytotoxic, in situ gelable hydrogels composed of N-carboxyethyl chitosan and oxidized dextran

Abstract

A series of in situ gelable hydrogels were prepared from oxidized dextran (Odex) and N-carboxyethyl chitosan (CEC) without any extraneous crosslinking agent. The gelation readily took place at physiological pH and body temperature. The gelation process was monitored rheologically, and the effect of the oxidation degree of dextran on the gelation process was investigated. The higher the oxidation degree of Odex, the faster the gelation. A highly porous hydrogel structure was revealed under scanning electron microscopy (SEM). Swelling and degradation of the Odex/CEC hydrogels in PBS showed that both swelling and degradation were related to the crosslinking density of the hydrogels. In particular, the hydrogels underwent fast mass loss in the first 2 weeks, followed by a more moderate degradation. The results of long-term cell viability tests revealed that the hydrogels were non-cytotoxic. Mouse fibroblasts were encapsulated in the hydrogels and cell viability was at least 95% within 3 days following encapsulation. Furthermore, cells entrapped inside the hydrogel assumed round shape initially but they gradually adapted to the new environment and spread out to assume more spiny shapes. Additionally, the results from applying the Odex/CEC system to mice full-thickness transcutaneous wound models suggested that it was capable of enhancing wound healing.

Microfluidic wet spinning of chitosan-alginate microfibers and encapsulation of HepG2 cells in fibers

“…Furthermore, encapsulation of cells is very challenging. [11][12][13] Therefore, a chitosan-alginate composite could address the limitations of the individual biopolymers. An important requirement for the practical application of biopolymers to tissue engineering is the ability to construct desired biopolymer scaffold structures and to load cells into the scaffold in a stable and easy manner.…”

Recent advances on the development of wound dressings for diabetic foot ulcer treatment—A review

“…In addition, chitosan amino and hydroxyl groups can be easily reacted and chemically modified, thus allowing a high chemical versatility. For example, chitosan may be modified into N-carboxymethyl chitosan [115], N-carboxybutyl chitosan [116,117], N-succinyl chitosan [118], N-acyl chitosan [119], N,O-(carboxymethyl) chitosan [120], N-N-dicarboxymethyl chitosan [121], N-carboxyethyl chitosan [122], O-succinyl chitosan [123], Ocarboxymethyl chitosan [124], 5-methylpyrrolidinone [125] and more. The conditions employed for amino group chemical modification may interfere with the final degree of deacetylation and therefore with the cationic nature of the obtained materials.…”

Noninvasive and High-Resolution Optical Monitoring of Healing of Diabetic Dermal Excisional Wounds Implanted with Biodegradable In Situ Gelable Hydrogels

“…We have recently developed a crosslinker-free, noncytotoxic, and bioresorbable Ncarboxyethyl chitosan and oxidized dextran composition that is capable of rapid in situ formation of tissue adherent hydrogels, 16 and we performed animal studies to demonstrate its efficacy for wound repair using conventional biopsied histology. 17,18 In this investigation, we sought to further validate the utility and identify potential limitations of OCT in monitoring the healing of diabetic dermal wound implanted with an enhanced in situ gelable hydrogel formulation comprised of N-carboxyethyl chitosan, oxidized dextran, and hyaluronan. Accordingly, we performed comparative implant-assisted wound-healing studies on a diabetic mouse model along with its normal=nondiabetic counterparts, and compared these results with nonassisted spontaneous wound healing.…”