Synthesis, characterization and antimicrobial properties of TiO2 and TiO2:Ag nanoparticle solutions and antimicrobial effect of inorganic biomaterials coated with these nanoparticles

• Grant number: 11/24004-0
• Support type: Regular Research Grants
• Duration: April 01, 2012 - September 30, 2014
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal Investigator: Ana Lucia Machado
• Grantee: Ana Lucia Machado
• Home Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

This research aims to prepare first nanoparticles solution of titanium oxide (TiO2) and silver-titanium oxide (TiO2:Ag) by solvothermal method. Nanoparticulated TiO2 has been widely studied due to its technological application as sensors, catalysis, energy conversion, among other. Thus, the development of synthesis methods in order to control the morphology and physicochemical properties of this material has been necessary. To obtain TiO2 nanoparticles, a complex of acetylacetone and titanium will be obtained from the titanium isopropoxide using isopropanol with subsequent hydrolysis in the presence of nitric acid. The colloid obtained will be then treated in solvothermal system, at 120°C, varying the treatment time. The same procedure will be used to obtain the TiO2:Ag nanoparticles, but silver ions will be added to the colloidal. Afterwards, a reducing agent (glucose/sucrose) will be used to precipitate silver on TiO2 nanoparticles. The characterization of these solutions obtained will be conducted by means of X-ray diffraction, Raman spectroscopy, infrared spectroscopy, ultraviolet-visible spectroscopy, photoluminescence, scanning electron microscopy and transmission electron microscopy. With this study, we hope to develop a synthesis method of TiO2 and TiO2: Ag nanoparticles which allow an adequate control of the characteristics of these synthesized materials for technological applications. The second part of this research aims to evaluate the antifungal and antibacterial effect of TiO2 and TiO2: Ag nanoparticles using the microorganisms Candida albicans (ATCC 90028) and methicillin-resistant Staphylococcus aureus - MRSA (ATCC 33591). The minimum inhibitory concentration (MIC) will be performed in 96-wells plates for planktonic cells (MIC) and biofilms (MICb). The MIC values will be determined by incubating the microorganisms for 24 hours at 37°C with serial dilutions (100%; 50%; 25%; 12.5%; 6.25%; 3.12%; 1.56%; 0.78%) of TiO2 and TiO2: Ag nanoparticles in culture media (YNB 100 mM and TSB for C. albicans and MRSA, respectively). The MIC values will be determined as the lowest concentration of TiO2 and TiO2: Ag nanoparticles in which no cell growth is observed by XTT assay. Additionally, C. albicans and MRSA biofilms will be developed under static and dynamic conditions on samples of inorganic biomaterials (ceramic and titanium alloy) coated with TiO2 and TiO2: Ag nanoparticles. Uncoated samples of these biomaterials will be tested as control group. The biofilm formation on the samples under these different conditions will be assessed by the following procedures: counting viable colonies (cfu/mL), XTT assay, determination of total biomass and analysis of confocal laser scanning microscopy. All tests will be carried out in triplicate on three separate occasions. The results will be statistically analyzed for further interpretation and discussion. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ANDRE, RAFAELA S.; ZAMPERINI, CAMILA A.; MIMA, EWERTON G.; LONGO, VALERIA M.; ALBUQUERQUE, ANDERSON R.; SAMBRANO, JULIO R.; MACHADO, ANA L.; VERGANI, CARLOS E.; HERNANDES, ANTONIO C.; VARELA, JOSE A.; LONGO, ELSON. Antimicrobial activity of TiO2:Ag nanocrystalline heterostructures: Experimental and theoretical insights. Chemical Physics, v. 459, p. 87-95, SEP 28 2015. Web of Science Citations: 10.

ZAMPERINI, C. A.; ANDRE, R. S.; LONGO, V. M.; MIMA, E. G.; VERGANI, C. E.; MACHADO, A. L.; VARELA, J. A.; LONGO, E. Antifungal Applications of Ag-Decorated Hydroxyapatite Nanoparticles. Journal of Nanomaterials, 2013. Web of Science Citations: 13.