The amniotic membranes were collected from the placentae of selected and screened donors. Processing was done by washing the fresh amniotic membrane successively in sterile saline, 0.05% sodium hypochlorite solution and sterile distilled water until it was completely cleared of blood particles. The membranes were sterilized by gamma irradiation at 25 kGy. The processed amniotic membranes were applied to 50 open wounds comprising of 42 full thickness defects and eight partial thickness defects. These included leprotic, diabetic, traumatic, gravitational ulcers and superficial burn in the form of scald and corrosive burn. The radiation processed amniotic membranes favoured healing of unresponsive and non-healing ulcers of different etiologies. Ulcers with duration of minimum 3 weeks to maximum 12 months were found to heal in 2-6 weeks by the application of amniotic membranes.

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Silver has been widely used as an antimicrobial agent in burn wound care. A number of dressings containing silver have been developed using textiles, polyurethane films, foams, hydrogels, and hydrocolloids. However, biological-derived wound dressings have been advocated for their ability to more effectively promote healing and regulation of evaporation and exudation at the wound site. An antimicrobial burn dressing was developed by impregnation of silver on the amniotic membrane. The dressing was assessed for antimicrobial effectiveness and physical properties of relevance to clinical performance. Silver-impregnated dressings exhibited antimicrobial activity in contact for 5 days. An in vitro evaluation of the microbicidal efficacy of the silver-impregnated dressing was performed using Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans with different contamination level. More than 95% reduction in viable counts was observed in 2 to 4 hours. The release of silver from the dressings was observed for up to 4 days. Moisture vapor transmission rate was 1037 +/- 38 g/m2/24 hr for silver-impregnated dressings and 1024 +/- 44 g/m2/24 hr for amniotic membrane. The fluid absorption by the silver-impregnated dressings was comparable to the amniotic membranes. The total fluid handling capacity of the silver-impregnated amniotic membrane dressing examined ranged from 4 to 6.6 g/10 cm2 in 24 to 96 hours. The silver-impregnated amniotic membranes also provided an effective barrier to bacterial penetration. The study has demonstrated the ability of silver-impregnated amniotic membrane to combat microbial infection and its ideal physical characteristics for clinical use as a burn wound dressing.

Chitin, a unique biopolymer based on the N-acetyl-glucosamine monomer is envisioned to promote rapid dermal regeneration and accelerate wound healing. It has many useful and advantageous biological properties for its application as a wound dressing. Chitin membranes were prepared using lithium chloride/dimethylacetamide solvent system and evaluated for use as a wound dressing. Swelling behaviour, moisture vapour transmission rate, microbial impermeability and antimicrobial efficacy of the dressings was evaluated. The chitin dressing provided an effective barrier to microbial penetration and exerted a broad bacteriostatic action against Gram-positive and Gram-negative organisms. Gamma irradiation at 25 kGy was found suitable for sterilisation of the dressings. The thermal decomposition of unirradiated and irradiated chitin membranes was investigated. No significant change in the thermal behaviour because of irradiation at 25 kGy was observed. In vitro biodegradation of unirradiated and irradiated chitin membranes showed the susceptibility of the chitin dressing to lysozyme. Irritant effect of the chitin membrane dressings on skin was tested. Subcutaneous and scarification test in guinea pigs showed no signs of inflammation. This was further supported by the Finkelstein's test performed in rabbits. The chitin membranes were found to have optimal performance characteristics of a wound dressing and showed no toxicity or possible adverse reactions. The study shows the chitin dressings as useful adjunct in wound care.