Antimicrobial activity and potential toxic effects in freshwater microalgae exposed to titanium dioxide miconanoparticles

• Grant number: 20/12323-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): January 01, 2021
• Effective date (End): December 31, 2021
• Field of knowledge: Interdisciplinary Subjects
• Principal Investigator: Cristiane Angélica Ottoni
• Grantee: Carolina Assis da Silva
• Host Institution: Instituto de Biociências (IB-CLP). Universidade Estadual Paulista (UNESP). Campus Experimental do Litoral Paulista. São Vicente , SP, Brazil

Abstract

Titanium dioxide has the ability to reflect and absorb UVA / UVB and adequate tolerance to human skin. Due to these characteristics, inorganic sunscreens have in their complex composition titanium dioxide (TiO2NP) nanoparticles. This metallic nanomaterial (NM) is produced on an industrial scale by physical-chemical routes. However, the need to develop new approaches to the synthesis of this NM is imminent, since the methods used produce a large volume of toxic waste and the obtained NM have a high index of toxic compounds adhered to its surface. In view of this demand, green nanotechnology has, among many objectives, to reduce the presence of residues generated during the synthesis, to implement sustainable processes and to increase the biocompatibility of these compounds. Different organisms are proposed in this type of approach, however filamentous fungi are the most promising. In this context, the present work aims to study the antimicrobial activity of two marine tamarins TiO2NP, present in suspension and encapsulated in alginate and, also, to evaluate potential toxic effects of these nanomaterials in a micro-algae. TiO2NP will be characterized by UV-vis spectrophotometry, 'Dynamic Light Scattering' (DLS), zeta potential (Pz), polydispersity index, X-ray diffraction (DRX) and Transmission Electron Microscopy (TEM). Antimicrobial activity will be evaluated by minimum inhibitory concentration using the pathogenic bacteria Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeroginosa and Staphylococcus aureus. The microalgae Chrorella vulgaris will be used for studies of cell density and viability. Given this, the possibility of replacing synthetic TiO2NP with biological, fungal origin, represents a promising alternative that meets the 2030 Agenda for Sustainable Development in the Goals (12) ensure sustainable production and consumption patterns and (13) Take action urgent measures to combat climate change and its impacts.