Biaxial Characterization of Auxetic Skin Graft Simulants

Expanding coverage of skin grafts is crucial in the healing of acute burn injuries that necessitate skin transplantation. Although many skin graft manufacturers have made claims of high expansions, the actual expansions achieved with skin grafts in practical settings have been considerably lower. This study aimed to investigate the possible expansion of skin grafts with auxetic patterns to improve the outcomes of severe burn injuries by increasing the skin graft area. Graft simulants with alternating slit patterns, I-shaped patterns, and Y-shaped patterns were developed using biofidelic skin material, and multiaxial load testing was conducted to calculate their void area values, stress values, strain values, and meshing ratio. The nonlinear characteristics of the graft simulants were characterized with the help of hyperelastic constitutive models. The results showed that I-shaped patterns of auxetic skin graft design had a low-stress value and higher meshing ratio than traditional grafts, indicating its potential to rapid wound healing and cover more significant skin at burn sites.