Abstract: BACKGROUND: The peracetic acid/ethanol is an ideal reagent for inactivating viruses of animal derived tissues and allogeneic tissues. It is effective in killing pathogenic microorganisms. However, its effect on other properties of allogeneic skin has not been reported.  
OBJECTIVE: To investigate the effect of peracetic acid/ethanol treatment on the performance of allogeneic skins.
METHODS:  Three different concentrations of peracetic acid/ethanol solutions were prepared, which were 2.3 g/L peracetic acid + 24% v/v ethanol (set as P/E-1), 1.8 g/L peracetic acid + 4.8% v/v ethanol (set as P/E-2) and 15.33 g/L peroxyacetic acid + 24% v/v ethanol (set as P/E-3). Allogeneic skin was treated with different concentrations of peracetic acid/ethanol for 15, 30, 45 and 60 minutes, respectively. The structural properties of the skin were evaluated via appearance, histological staining, mechanical test and glycosaminoglycan content test. Besides, chemical reagent residues and cytotoxicity in the treated skin were also studied.  
RESULTS AND CONCLUSION: (1) No significant difference in the epidermal appearance of skin were observed at all investigated concentrations of peracetic acid/ethanol. (2) Hematoxylin-eosin staining showed no obvious changes in the extracellular matrix structure of skin after 15 minutes of P/E-1 and P/E-2 treatment compared with untreated allogeneic skin, and the extracellular matrix structure of skin treated with more than 15 minutes was relatively loose which preserved an integral structure. However, microporous appeared in the dermis while it was treated for 15 minutes, especially after 15 minutes, more holes appeared in the dermis and the extracellular matrix structure was seriously destroyed. (3) The longer the treatment time at the same concentration, the lower the glycosaminoglycan content and the lower the mechanical strength and modulus. With the same treatment time, the tensile strength of the P/E-1 treatment group was the largest, while the P/E-3 treatment group was the smallest; the elongation at break of the P/E-2 treatment group was the largest, while the P/E-3 treatment group was the smallest; and E-3 treatment group had the least toughness. (4) Reagent residual assay showed that peracetic acid and ethanol have been verified to be removed from the allogeneic skin after washing, with low cytotoxicity within limits required. (5) The results displayed under the same processing time, the skins of P/E-1 group have the closest properties and structure compared to the raw material.

Key words: material, virus inactivation, allogeneic skin, acellular dermal matrix, peracetic acid-ethanol