This work aimed to develop a glycerol antimicrobial peptide natural latex film (NRL-GI-AMP film) for the treatment of skin wound infections. The contents of this work mainly include investigating the effect of adding glycerol (GI) and an antimicrobial peptide (AMP) on the physical and chemical properties of natural latex (NRL) and analyzing the cytocompatibility, bacteriostatic activity, and infected wound healing promotion of the NRL-GI-AMP film. The results showed that the addition of GI resulted in more pores in the internal structure of the NRL film, while the addition of G(LLKK)3L AMP did not change the structure and properties of the NRL film. Compared with that of the NRL film, the infrared spectrum of the NRL-GI-AMP film did not produce new characteristic peaks, indicating that GI and AMP were non-covalently cross-linked with NRL. Addition of 10% GI reduces the toughness of the NRL-GI-AMP film by 62.0%, increases the water vapor transmission rate by 8.95 mg/(cm2·h), and reduces the water absorption and water retention distributions by 33.0 and 24.7%, respectively. AMP in the NRL-GI-AMP film could be released continuously for 40 h, and the release rate was about 45%. The NRL-GI-AMP film showed good biocompatibility and antibacterial activity and promoted the healing of infected wounds. Therefore, the NRL-GI-AP film has potential application in the development of dressings to inhibit skin wound infection and promote wound healing.

In an attempt to develop new antimicrobial peptides (AMPs) with better biological properties, three AMPs of (LLKK)3 analogues were designed and synthesized. The antibacterial activity, cell toxicity and pepsin stability of the three AMPs were determined, and the antibacterial action of the candidate AMP was analyzed. The results showed that the G(LLKK)3L AMP had the stronger antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) compared to the other AMPs. The hemolytic activity and cytotoxicity of the G(LLKK)3L and G(LLKK)3 AMPs were lower than those of (LLKK)3 and (LLKK)3L AMPs, and the pepsin resistance activity of the G(LLKK)3L AMP was higher than that of the other AMPs. Under the treatment of G(LLKK)3L AMP, the cell morphology of the E. coli and S. aureus was irregular and wrinkled, their cell membrane was damaged, and the synthesis of their cell wall peptidoglycan was inhibited. Additionally, the G(LLKK)3L AMP resulted in a decrease of protein expression and inhibition of DNA synthesis. In summary, the G(LLKK)3L AMP exhibited better biological properties, and it can be used as a therapeutic agent against E. coli and S. aureus.