Spidroin in carbopol-based gel promotes wound healing in earthworm's skin model

Spider silk's regenerative, biocompatible, and antimicrobial properties render it a promising biomaterial for wound healing promotion. Spidroin as the main protein component of spider silks was used in this study to evaluate the potential effects on wound healing via topical application of novel spidroin-containing carbopol 934 (CP934) gel. Spidroin was extracted, formulated into CP934 gel, and characterized both in vitro and in vivo. Spidroin gel was translucent and brownish-yellow in color. An optimum viscosity was obtained at 0.6% CP934 at neutral pH. Optimized spidroin gel (0.6% CP934) effectively inhibited the growth of clinical bacterial isolates of methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant S. aureus (MRSA) and Escherichia coli at 440 μg/mL with MIC values of 0.98, 4.6, and 8.2 μg/mL, respectively. Optimized spidroin gel was evaluated for wound healing via topical application on wounds surgically induced in Allolobophora caliginosa earthworms used as a robust human skin model. After application for three consecutive days, dramatic reductions in wound closure and reepithelialization duration were observed macroscopically and via histological studies (light and electron microscopy) when compared with control. In conclusion, these results show that spidroin gel is a promising promoter for wound healing, and further studies would be directed toward investigating mechanisms underlying this effect.