Understanding the Uptake Mechanism and Interaction Potential of the Designed Peptide and Preparation of Composite Fiber Matrix for Fungal Keratitis

The conventional use of antibiotics for the treatment of infectious keratitis currently faces two major challenges: poor drug penetration and the emergence of antibiotic resistance in microbial strains. Cell-penetrating peptides (CPPs) with antimicrobial properties have the potential to address these challenges. However, their mode of action, mechanism of uptake, and interaction potential have not been explored in detail. In this study, we probed the mechanism of uptake and interaction potential of our previously designed peptides (VRF005 and VRF007). Our results showed that VRF005 undergoes direct translocation and induces a rough membrane surface, whereas VRF007 undergoes clathrin-mediated endocytic uptake. The gel shift assay showed that VRF005 is bound to genomic DNA, whereas VRF007 is bound to chitin and β-d-glucan. Gene expression studies revealed the effect of peptide VRF005 on Candida albicans transcription. Molecular docking and simulations showed that VRF005 forms noncovalent interactions (such as H-bonding and water bridges) with natamycin. It exhibited synergistic antifungal activity in the colony-forming assay. VRF005, functionalized in the polycaprolactone fiber matrix, showed sustained delivery and antifungal activity.