ASSESSMENT OF BIOFUNCTIONALIZATION ON CORROSION EFFECTS IN Ti-6Al-4V ALLOY WITH ANTIMICROBIAL PEPTIDE JI-2

Titanium-based materials are widely used in the biomedical sector for implantable devices due to their mechanical performance and remarkable biocompatibility in biological environments. Despite these advantages, implants made from such materials may still exhibit failures associated with microbial adhesion to the metallic surface. A promising strategy to overcome these challenges involves surface functionalization through biomolecule immobilization, conferring additional properties such as antimicrobial, antifungal, and antioxidant activity, while enhancing biocompatibility. Therefore, this study aimed to investigate the electrochemical behavior of Ti-6Al-4V after plasma polymerization of acrylic acid (PAA) and subsequent functionalization with the antimicrobial peptide JI-Chis-2 (JI-2) analogous to Jelleine, a compound derived from royal jelly with potent antimicrobial activity. Open Circuit Potential (OCP) and Electrochemical Impedance Spectroscopy (EIS) measurements were performed in an aggressive environment at different immersion times. Additionally, morphological analyses of the samples were performed via Scanning Electron Microscopy (SEM). Results demonstrated that plasma polymerization enabled the formation of PAA thin film on the surface of Ti-6Al-4V. The incorporation of the JI-2 peptide shifted the potential towards less negative values compared to the non-functionalized alloy, suggesting improved corrosion resistance. The functionalized samples showed a higher impedance modulus than the base material for up to 5 hours, indicating an initial protective effect provided by the peptide. However, in 168 h, a decrease in the impedance modulus was observed, probably associated with partial degradation of the PAA thin film and cationic agglomerate of peptides on the metallic surface. In contrast, the non-functionalized material displayed a gradual increase in impedance over the same period, probably due to the formation of a passive TiO₂ layer on the surface. These findings highlight the biological and technological relevance of antimicrobial peptide functionalization, demonstrating its direct influence on corrosion resistance and reinforcing the importance of integrated surface modification strategies in biomedical applications.

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq - Grants: 303659/2019-0, 402988/2021-3, 302770/2022-4, and 302582/2021-5), the Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG - Grants: APQ-0227618, APQ-01359-21, and APQ-00554-21), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES - Funding Code 001).