Carboxymethyl chitosan nanoparticles loaded with bioactive peptide OH-CATH30 benefit nonscar wound healing

Background: Nonscar wound healing is a desirable treatment for cutaneous wounds worldwide. Peptide OH-CATH30 (OH30) from king cobra can selectively regulate the innate immunity and create an anti-inflammatory micro-environment which might benefit nonscar wound healing. Purpose: To overcome the enzymatic digestion and control release of OH30, OH30 encapsulated in carboxymethyl chitosan nanoparticles (CMCS-OH30 NP) were prepared and their effects on wound healing were evaluated. Methods: CMCS-OH30 NP were prepared by mild ionic gelation method and properties of the prepared CMCS-OH30 NP were determined by dynamic light scattering. Encapsulation efficiency, stability and release profile of OH30 from prepared CMCS-OH30 NP were determined by HPLC. Cytotoxicity, cell migration and cellular uptake of CMCS-OH30 NP were determined by conventional methods. The effects of prepared CMCS-OH30 NP on the wound healing was investigated by full-thickness excision animal models. Results: The release of encapsulated OH30 from prepared CMCS-OH30 NP was maintained for at least 24 h in a controlled manner. CMCSOH30 NP enhanced the cell migration but had no effects on the metabolism and proliferation of keratinocytes. In the full-thickness excision animal models, the CMCS-OH30 NP treatment significantly accelerated the wound healing compared with CMCS or OH30 administration alone. Histopathological examination suggested that CMCS-OH30 NP promoted wound healing by enhancing the granulation tissue formation through the re-epithelialized and neovascularized composition. CMCS-OH30 NP induced a steady anti-inflammatory cytokine IL10 expression but downregulated the expressions of several pro-inflammatory cytokines. Conclusion: The prepared biodegradable drug delivery system accelerates the healing and shows better prognosis because of the combined effects of OH30 released from the nanoparticles.