The development of an artificial skin model and its frictional interaction with wound dressings

Human skin interacts with various materials in our daily life. The interaction between human skin and contacting materials is very important for the development of skin contacting products. Owing to the ethic and different testing results because of the using of in vivo or ex vivo skin, it is important to develop an artificial skin model (ASM) for the study. Therefore, an ASM mimicking the deformation and friction behavior of in vivo human skin was designed based on the evaluation of in vivo human skin behavior, and its frictional interaction with wound dressings was studied. The ASM was prepared by the combination of hydrophilic network carboxyl chitosan (CC) and hydrophobic network polydimethylsiloxane (PDMS). The influence of ingredient ratio, including PDMS/CC and curing agent/PDMS ratio, on the mechanical property of ASM was determined firstly. By adjusting the curing agent/PDMS ratio, the water absorption swelling rate (WASR) of ASM could be controlled to mimic different hydration status of human skin. With the changing of ingredient ratio and hydration level, the elastic modulus and viscoelasticity of ASM can be tailored to be similar to that of in vivo human skin. When the PDMS/CC ratio was 7:3, and PDMS/curing agent ratio was smaller than 1:30, the elastic modulus of ASM was in the range of in vivo inner forearm, and with the increasing of indentation depth, the elastic modulus decreased. Based on the ASM, the frictional interaction between skin/wound dressing/mattress was studied. It was found that although the friction using ASM was slightly higher than that using in vivo inner forearm, but the friction decreasing trend was the same for different kinds of wound dressings. In addition, the friction tested with ASM was less fluctuation, more reliable and reproducible than that tested with in vivo skin, indicating that the ASM was suitable to be used for the studying of frictional interaction between skin and product, such as wound dressings.