Antibiotics-free wound dressing combating bacterial infections: A clean method using silkworm cocoon shell for preparation

Abstract

Silk biomaterials have been attracting significant attention in medical bioengineering because of their versatile function, morphologic flexibility, and excellent biocompatibility. The present study was inspired by the shielding and protective function of the silkworm cocoon shell (SCS) to the silkworm chrysalis, which is notably similar to the protective effect of skin on the body. SCS was treated and used as the base substrate for dressing materials to promote wound healing; for this, a facile approach to maintaining its original framework was proposed. By treatment with a ternary solution, the original compact 2D SCS was upgraded to a transparent 3D macro-chambered sheet (MCS) this was followed by the loading of gold nanoparticles (AuNPs) to form MCS-Au and by the self-assembly of methimazole (ME) over AuNPs, the new composite material MCS-Au@ME was obtained. This new material exhibited excellent antibacterial properties against four bacterial strains without the use of antibiotics. Animal testing indicated that the performance of MCS-Au@ME in the promotion of wound healing was superior to that of the commercial product, Mepitel® Soft Silicone Wound Contact Layer. The present study abandoned the conventional sophisticated and lengthy preparation process for silk biomaterials that involved dissolution and remodeling and also eliminated the inclusion of antibiotics to reduce the threat of antibiotic abuse—which has been an issue of concern in medical antibacterial applications. This study brings new insights into the selection and sustainable processing of silk for wound dressing.