Targeted antimicrobial peptide delivery in vivo to tumor with near infrared photoactivated mesoporous silica nanoparticles

Antimicrobial peptide PA-C1b (chensinin-1b conjugated with palmitic acid) showed potent anticancer activity with no obvious hemolytic activity, which made it a potential agent for treating cancers. However, after in vivo administration, peptides can be degraded by proteases because there is no effective protection. In this study, a tumor-targeting photoresponsive antimicrobial peptide delivery system was developed, and the peptide PA-C1b labeled with the dye sulfo-cyanine7 (Cy7) was loaded into mesoporous silica nanoparticles (MSNs). The final MSN@Cy7-PA-C1b nanoparticles were wrapped by graphene oxide (GO), and then folic acid was conjugated to the surface of the MSNs for targeting purposes. The final MSN@Cy7-PA-C1b@FA-GO nanoparticles were constructed to allow light-mediated peptide release and folate receptor-targeted cancer therapy. The Cy7 dye serves as a real-time indicator, and GO acts as a gatekeeper to prevent leakage of the loaded peptides in the absence of near-infrared light irradiation. Upon light irradiation, the GO wrapping detaches, and the photoresponsive peptide delivery system works well both in in vitro cell experiments and during in vivo administration in mouse tumor experiments. The construction of the MSN@Cy7-PA-C1b@FA-GO platform provides a novel approach to deliver antimicrobial peptides in vivo for the treatment of infections by pathogenic microorganisms and cancers.