Zinc-doped coating with photocatalytic potential for antimicrobial effect and osteogenic and immunological modulation: in silico, in vitro, in situ, and in vivo studies

• Grant number: 24/21386-9
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2025
• End date: February 28, 2029
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Valentim Adelino Ricardo Barão
• Grantee: Samuel Santana Malheiros
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Building on the advances achieved during the proponent's master's project (FAPESP grant nº 15677-5), which developed a multifunctional zinc-doped (Zn) coating by plasma electrolytic oxidation (PEO) with promising antibacterial and bioactive properties, this doctoral project aims to explore photocatalysis as a strategy to enhance the antimicrobial effect of the coating, transforming it into an intelligent, light-responsive biomaterial with on-demand action and the potential for continuous and long-lasting antimicrobial control. Additionally, this study aims to evaluate the osteogenic and immunomodulatory potential of the coating. For this purpose, commercially pure titanium disks and dental implants will undergo two surface treatments: aluminum oxide blasting followed by acid etching (control group - SLA) and PEO treatment with Zn doping (experimental group - Zn). Subsequently, four studies will be conducted: (1) In silico study, aiming to characterize the optical properties of the Zn coating and optimize visible light activation conditions; (2) In vitro study, to evaluate the photocatalytic potential, reactive oxygen species (ROS) generation, shelf life, and direct antimicrobial effect, with or without visible light, and its impact on microbial composition (microcosm model with human saliva), in addition to assessing cytocompatibility and osteogenic potential in pre-osteoblastic cells and the immunomodulatory effect in macrophages; (3) In situ study, in which 12 volunteers will use palatal devices containing SLA and Zn disks for 7 days to allow biofilm formation, which will then be irradiated or not with visible light and analyzed immediately and after 24 hours (reinfection) in terms of viability, morphology, and microbial composition; and finally (4) In vivo study, to investigate the osseointegration potential of SLA and Zn implants through histological analyses, micro-computed tomography, and bone-to-implant contact measurement, as well as biomechanical and molecular testing. The in vivo study will also address the peri-implant inflammatory response through quantification of pro-inflammatory cytokines (IL-1 betha and TNF-alpha) and evaluation of the antimicrobial effect of the Zn coating, with and without visible light activation, by counting CFU on disks implanted in the dorsal region of rats. The data obtained will be subjected to descriptive statistics and assumptions analysis to define the appropriate tests, with a significance level of 0.05.