High-strength cellulose/chitin blended hydrogel membranes were fabricated via a solution pre-gelation method. The morphology and structure of the resultant membranes were investigated by SEM, WXRD and FTIR. The mechanical properties and permeability of the membranes were determined by tensile test and in situ UV–visible spectrophotometry. Instead of the loose mesh-like structure and high crystallinity of the common membranes, remarkably dense aggregation structure and low crystallinity of the novel cellulose/chitin membranes were successfully created through the solution pre-gelation process. It effectively promoted the mechanical performance of the hydrogel membranes. Moreover, the structure and properties of the membranes closely depended on the chitin content and pre-gelation temperature. Dynamic rheology studies revealed the gelation-dynamics of the mixed solution accelerated and decelerated with chitin content. ATR-FTIR results indicated nonsolvent-induced phase-separation was the main mechanism for the formation of such membranes with special structure and improved performance.

There is increasing evidence showing that adult stem cells are useful for tissue regeneration. Bone marrow mesenchymal stem cells (MSCs) are self-renewing and are potent in differentiating into multiple cells and tissues. To investigate the practicability of repairing burn wounds with tissue-engineered (TE) skin combined with bone MSCs, we established a burn wound model in the porcine skin. With a controlling temperature and time of the burning device to obtain different degrees of burn wounds, a deep dermal partial thickness burn was introduced to the porcine skin using a heated-brass contact injury at 100 degrees C for 20 s. Collagen-GAG scaffolds were utilized as the matrix; MSCs separated from pigs were seeded on them to form the skin equivalent. When grafted to the burn wounds, the TE skin containing MSCs showed better healing and keratinization, less wound contraction, and more vascularization. Grafts proliferated well and contributed to the neo-tissues. These data suggest that TE skin containing MSCs in a burn defect can accelerate wound healing and receive satisfactory effects.

Acute skin defects often cause many adverse events such as abnormal pigmentation and scar formation, the satisfactory healing of which remains a significant clinical challenge. Over the past several decades, a number of skin equivalents have been available for clinical purposes to promote wound closure. However, the true values of skin equivalent - tissue-engineered skin (TE-skin) composed of neonatal fibroblasts and keratinocytes - in improving the quality of wound healing are not yet elucidated. A total of 158 patients were enrolled, 129 of which were used in this study. In these patients, acute skin defects were treated with TE-skin as experimental group, and treated with Vaseline primary dressing as control group. The differences in average healing times between the two groups were determined with statistical analysis according to different depths of skin defects. Wound quality, including pigmentation, cicatrization, and pliability, was assessed by investigators from different clinical centers over a 6-month period. The cosmetic outcome of the wound was further evaluated with histological method. In the study, the average time of wound closure in the experimental group was significantly shortened by 6.5 to 20 days according to different depths of skin defects. The cosmetic quality of reconstructed skin was satisfactory, with the patients enjoying better pliability, less abnormal pigmentation, and cicatrization. Safety analysis demonstrated that the wounds treated with TE-skin did not show clinical or laboratory evidence of rejection during the trial. These results indicate that TE-skin is a suitable and clinically effective treatment for various acute skin defects. Furthermore, the TE-skin appears to produce more satisfactory cosmetic results when compared with the conventional therapy.