Deposição do peptídeo análogo à Jelleine-I (JI-2) na liga Ti-6Al-4V para aplicações biomédicas

Abstract

Titanium alloys are among the most used materials in the health area for the production of implantable devices. Attribution that is due to its mechanical properties and the high biocompatibility presented in the media of interest. Ti-6Al-4V alloy has been widely used for orthodontic applications (brackets and/or implants). However, the permanence of these devices, in a physiological environment, triggers oxidation-reduction processes and the proliferation of microorganisms, which impact both their useful life and the quality of life of their users. The immobilization of biofunctional molecules on the surface of these materials has proven to be an effective way to functionalize them with various biological properties, namely: antimicrobial, antifungal and antioxidant. In addition, this strategy can contribute to both the improvement of the biocompatibility and the corrosive properties of these materials. In view of these aspects, this research aimed to immobilize a new antimicrobial peptide JI-Chis-2 (JI-2), analogue of Jelleine-I, in the Ti-6Al-4V alloy. To then promote the improvement of the antimicrobial properties of the biomaterial. Peptide immobilization occurred after PAA deposition via PECVD. Functionalized and non-functionalized surfaces were characterized using AFM, FTIR, SEM and EDX. The results indicated the successful deposition of PAA and immobilization of peptides on the metallic surface. Through the morphological and topographical characterizations, it was verified that the peptide tends to form agglomerates on the metallic surface. Additionally, an immersion test was carried out in an aggressive environment, seeking to explore the effects triggered by surface treatment in an aggressive environment. With these tests, it was possible to verify that the deposition of the acrylic acid thin film acts as a protective barrier against corrosion in the material. This effect was also evidenced by localized corrosion tests performed via SVET at different immersion times. However, the corrosion process was intensified on the surfaces containing JI-2 due to the electrostatic interaction between the cationic peptide clusters and the aggressive ions in the medium. Furthermore, an investigation was carried out on the electrochemical behavior of Ti-6Al-4V functionalized with PAA/JI-2 in aggressive media. For this, the techniques of OCP and EIS were used. The antimicrobial activity of JI-2 was evaluated against Gram-negative bacteria E. coli. Furthermore, biological assays have shown that the functionalized material has the ability to prevent the formation of E. coli biofilms. These findings show that the strategy of immobilizing JI-2 on the Ti-6Al-4V alloy via PAA PECVD resulted in the development of a functional material with antibiofilm properties.