Development of a mussel-inspired titanium coating: association of poly-l-lysine and catechol as an antimicrobial strategy for dental implants application.

• Grant number: 24/05142-2
• Support Opportunities: Scholarships in Brazil - Master
• Start date: December 01, 2024
• End date: March 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Valentim Adelino Ricardo Barão
• Grantee: Ayrton Geroncio Silva
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

The complex interactions between oral microorganisms present in the biofilm of peri-implant diseases and the host'sdefenses can lead to imbalances in the oral environment, resulting in degradation of the protective titanium oxide layeron dental implants. These interactions induce the inflammatory process that damages the supporting tissues, leading tofailures in rehabilitative treatment, compromising the integrity and durability of the implants. Thus, the aim of the presentstudy is to develop an antimicrobial, bioactive, and adhesive coating for the surface of dental implants, using poly-L-lysine(PLL) as a biopolymer. Recognized for its cationic and antibacterial properties, PLL will be combined with catechol (PLLC)in an approach inspired by the adhesive characteristics of mussels to ensure adhesion and resistance to the substrate, inwhich the substrate is commonly hydrothermally treated (HT) to promote film bonding to hydroxyl radicals. In this study,we also propose to investigate the effect of PLLC on titanium substrates previously treated with plasma electrolyticoxidation (PEO) instead of HT. This potential stems from PEO's ability to serve as a physical-chemical adhesion platformfor the PLLC film on titanium, owing to its porous morphology and the presence of hydroxyl radicals. Additionally, offersadvantages derived from its excellent mechanical, tribological, electrochemical, and bioactive properties. Thus, thefollowing surface modifications on titanium will be tested: (1) HT (control); (2) PEO (control); (3) HT followed by PLLCdeposition; (4) PEO followed by PLLC deposition. Additionally, to determine the ideal concentration that offers the bestcombination of antimicrobial, biological, and mechanical properties, each PLLC-containing group will be tested in two PLLconcentrations: 40 mM and 50 mM. Initially, surface characterizations will be performed regarding morphology, chemicalcomposition, roughness, wettability, and crystallinity, as well as analysis of mechanical and electrochemical properties.The adhesiveness of PLLC will be tested through tribological and pull-off assays. The antimicrobial behavior of the coatingagainst monospecies biofilm (Streptococcus oralis and Porphyromonas gingivalis) and polymicrobial biofilm will beevaluated in vitro. Surface interactions will be analyzed regarding protein adsorption and cytocompatibility with preosteoblastic cells (MC3T3-E1). Data will be subjected to the most appropriate statistical analysis considering ± = 0.05.