Silk fibroin (SF) has been widely used as a
wound dressing material due to its suitable physical and
biological characteristics. In this study, a non-adhesive
wound dressing which applies to cover the
wound surface as an
absorbent pad that would absorb
wound fluid while accelerate wound healing was developed. The modification of SF fabrics by wax coating was purposed to prepare the non-adhesive
wound dressing that is required in order to minimize
pain and risk of
repeated injury. SF woven fabrics were coated with different types of
waxes including
shellac wax,
beeswax, or
carnauba wax. Physical and mechanical properties of the wax-coated SF fabrics were characterized. It was clearly observed that all
waxes could be successfully coated on the SF fabrics, possibly due to the hydrophobic interactions between hydrophobic domains of SF and
waxes. The wax coating improved tensile modulus and percentage of elongation of the SF fabrics due to the denser structure and the thicker fibers coated. The in vitro degradation study demonstrated that all wax-coated SF fabrics remained up to 90% of their original weights after 7 weeks of incubation in
lysozyme solution under physiological conditions. The wax coating did not affect the degradation behavior of the SF fabrics. A peel test of the wax-coated SF fabrics was carried out in the partial- and full-thickness
wounds of porcine skin in comparison to that of the commercial
wound dressing. Any wax-coated SF fabrics were less adhesive than the control, as confirmed by less number of cells attached and less adhesive force. This might be that the wax-coated SF fabrics showed the hydrophobic property, allowing the loosely adherence to the hydrophilic
wound surface. In addition, the in vivo biocompatibility test of the wax-coated SF fabrics was performed in Sprague-Dawley rats with subcutaneous model. The irritation scores indicated that the
carnauba wax-coated SF fabric was not
irritant while the
shellac wax or
beeswax-coated SF fabrics were slightly
irritant, comparing with the commercial
wound dressing. Therefore, SF fabrics coated with
waxes, particularly
carnauba wax, would be promising choices of non-adhesive
wound dressing.