Development of antimicrobial biomaterials functionalized with copper for dental application

Author(s)

Jairo Matozinho Cordeiro

• Document type: Doctoral Thesis
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2021-12-21

Examining board members

Valentim Adelino Ricardo Barão; Jamil Awad Shibli; Heloísa Fonseca Marão; Diana Gabriela Soares dos Passos; Renata Cunha Matheus Rodrigues Garcia

• Advisor: Valentim Adelino Ricardo Barão

Abstract

Biofilm accumulation is one of the main factors involved in the failure of dental implant rehabilitation. Surface treatments for implants and membranes for guided bone regeneration (GBR) in current clinical use do not have antimicrobial capacity. Thus, the need to develop biomaterials that could assist in recruiting endogenous stem cells, supporting and stimulating the innate bone regeneration is still ongoing. Therefore, this work aimed: (1) to synthesize and characterize antimicrobial and bioactive coatings onto titanium (Ti) to be applied as surfaces for dental implants produced by plasma electrolytic oxidation (PEO) and using different copper (Cu) sources: copper acetate (CuAc), copper sulfate (CuS), and copper oxide (CuO); (2) to develop and evaluate membranes containing Cu oxide (CuO 1%, CuO 0.5%, CuO 0.1%, and CuO 0.05%; wt. %) for GBR formed by electrospinning technique. The morphological, structural, chemical and mechanical properties of the biomaterials were evaluated. In vitro cytocompatibility experiments were performed with human bone mesenchymal stem cells and human umbilical vein endothelial cells. The antibacterial potential of biomaterials was tested by biofilm formation of Streptococcus sanguinis for PEO coatings and Staphylococcus aureus for GBR membranes. One-way ANOVA and Tukey test was used for multiple comparisons (p < 0.05). Cu-containing coatings for dental implants were successfully developed by PEO using different Cu sources, which were able to affect the morphology and composition of the coatings, also influencing their effect on human cells and bacteria. The surface roughness of the coating and Cu ions release generated by distinct sources used to functionalize the Ti influenced the biofilm formation. An optimized topography of the coating produced with CuAc led to biofilm formation inhibition and an increase in cellular responses. Cu-loaded GBR membranes with different concentrations were successfully synthesized by the electrospinning technique. Cu concentration was crucial for biological responses, in which higher concentrations showed better antimicrobial activity, but decreased cytocompatibility. Membranes with a lower concentration of Cu showed good mechanical properties, supporting and stimulating human cell adhesion and proliferation, as well as angiogenesis. The use of Cu as a functionalizing agent for two different biomaterials seems to be promising. Both strategies presented in this study may be valuable alternatives to reduce the risk of infections and improve the process of osseointegration and tissue regeneration, consequently, accelerating the rehabilitation treatment with dental implants (AU)

• FAPESP's process: 17/01320-0 - Development of a bioactive and antibacterial surface containing Cu2O for dental implants
• Grantee: Jairo Matozinho Cordeiro
• Support Opportunities: Scholarships in Brazil - Doctorate