Bacterial cellulose matrix with in situ impregnation of silver nanoparticles via catecholic redox chemistry for third degree burn wound healing.

In the present study, bacterial cellulose (BC) based nanocomposite dressing material was developed for third burn wound management by polydopamine (PD) coated BC with in situ reduction of silver nanoparticles (BC-PDAg). BC-PDAg nanocomposite was characterized to understand the morphological, physical and chemical properties. Antimicrobial activity of BC-PDAg against burn wound specific pathogens were significant. The in vitro cytotoxicity and proliferation studies revealed that BC-PDAg nanocomposite is biocompatible and it supports cell proliferation. Further, in vivo experiments on female albino Wistar rats confirmed that BC-PDAg was effective in wound healing by promoting re-epithelization, and collagen deposition as evidenced by histopathological analysis. Moreover, molecular gene expression study has revealed that BC-PDAg promotes healing process by regulating the expression of inflammatory, angiogenesis and growth factor genes. The overall performance of BC-PDAg nanocomposite suggests that it could be used as promising skin regenerative tool in modern medicine.

Total salinity elimination during preservation of animal skins: a sustainable approach through benign alternatives.

Use of sodium chloride to preserve animal skins and hides is becoming increasingly untenable due to stringent environmental regulations. In the present research work, a combination of sparingly soluble alkali and water-soluble polymer of ethylene oxide has been used to preserve skins with an objective of total elimination of common salt for preservation. A comprehensive study has been made for evaluating various parameters, such as dehydration and rehydration behaviours of skins, microbial growth, emission loads and physico-chemical characteristics of the cured skin to validate the salt-free preservation system developed. The shrinkage temperature, denaturation temperature and mechanical strength of tanned leather were analysed by using shrinkage, differential scanning calorimetric and thermomechanical analysis techniques. The new curing system has been found to be effective in preserving the skin as indicated by the various parameters studied and the final leather quality. The significant reduction in total solids content such as dissolved solids and suspended solids present in the effluent compared to conventional preservation method is evident from environmental impact assessment studies.

Thymol enriched bacterial cellulose hydrogel as effective material for third degree burn wound repair.

Bacterial cellulose is well known for its excellent contributions in biomedical applications due to its superior properties. However the lack of antimicrobial property restricts its use in wound healing. To address the complications in third degree burns, thymol enriched bacterial cellulose hydrogel (BCT) was developed in this study. The incorporation of thymol into bacterial cellulose along with its chemical and thermal changes were investigated by FTIR, TGA and DSC respectively. Antimicrobial studies revealed that BCT possess excellent biocidal activity against burn specific pathogens. The in vitro biocompatibility studies were carried out in mouse 3T3 fibroblast cells. The BCT hydrogel facilitated the growth of fibroblast cells, exhibiting low toxicity, and increased cell viability. The burn wound healing efficiency of the BCT hydrogel was examined in vivo using female albino Wistar rats. Histopathological studies reveal that the wound treated with BCT hydrogel showed faster wound closure than BC and control groups. All these findings, suggest that BCT hydrogel can be used as resourceful and natural burn wound dressing material.

Cleaner processing: a sulphide-free approach for depilation of skins.

The conventional unhairing process in leather making utilises large amount of lime and sodium sulphide which is hazardous and poses serious waste disposal concerns. Under acidic conditions, sodium sulphide liberates significant quantities of hydrogen sulphide which causes frequent fatal accidents. Further, the conventional unhairing process involves destruction of the hair leading to increased levels of biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS) and total suspended solids (TSS) in the effluent. A safe approach is needed to overcome such environmental and health problems through an eco-benign process. The present study deals with a clean technology in which the keratinous body is detached from the dermis using enzymes produced from Bacillus crolab MTCC 5468 by solid state fermentation (SSF) as an alternative to noxious chemicals. Complete unhairing of skin could be achieved with an enzyme concentration of 1.2 % (w/w). The bio-chemical parameters of the spent liquor of the enzymatic process were environmentally favourable when compared with conventional method. The study indicates that the enzymatic unhairing is a safe process which could be used effectively in leather processing to alleviate pollution and health problems.

Use of ultrasound in leather processing industry: effect of sonication on substrate and substances--new insights.

Influence of ultrasound (US) on various unit operations in leather processing has been studied with the aim to improve the process efficiency, quality, reduce process time and achieve near-zero discharge levels in effluent streams as a cleaner option. Effect of US on substrate (skin/leather) matrix as well as substances used in different unit operations have been studied and found to be useful in the processing. Absorption of US energy by leather in process vessel at different distances from US source has been measured and found to be significant. Effect of particle-size of different substances due to sonication indicates positive influence on the diffusion through the matrix. Our experimental results suggest that US effect is better realized for the cases with pronounced diffusion hindrance. Influence of US on bioprocessing of leather has been studied and found beneficial. Attempts have also been made to improve the US aided processing using external aids. Operating US in pulse mode operation could be useful in order to reduce the electrical energy consumption. Use of US has also been studied in the preparation of leather auxiliaries involving mass-transfer resistance. Preliminary cost analysis carried out for ultrasound-assisted leather-dyeing process indicates scale-up possibility. Therefore, US application provide improvement in process efficiency as well as making cleaner production methods feasible. Hence, overall results suggest that use of US in leather industry is imminent and potential viable option in near future.