Banca de QUALIFICAÇÃO: Thalita Fonseca de Araujo

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : Thalita Fonseca de Araujo
DATE: 24/11/2023
TIME: 08:30
LOCAL: Google Meet
TITLE:

"Low-Cost Inserts production for nanotoxicological assays."

KEY WORDS:

metallic nanoparticles; synthesis modulation, eco-friendly; antibacterial; bimetallic.

PAGES: 79
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Among the ways to synthesize metallic nanoparticles (NPMs), there is the chemical synthesis, that uses reagents that can be toxic to the environment and to the human being; and there is the green synthesis, that utilizes, mainly, but not only, biological resources to synthesize such nanomaterials. This approach has many advantages regarding chemical synthesis: low cost, its eco-friendly, low toxicity of the process and the vast availability of the biological resources to be utilized. Although, there is few studies that evaluate if there is a difference in the toxicity of the nanoparticles regarding its synthesis method. Among the methodologies available to assess the toxicity of nanomaterials, there is those based in Boyden chambers, nonetheless the high value of such material limits its application in more laboratories. In such manner, this work aims to produce a low-cost insert using a tridimensional printer for cytotoxic assays of metal nanoparticles produced by chemical and green routes. Silver nanoparticles (AgNPs), iron (FeNPs), copper-silver (CuAgNPs) and silver-iron (AgFeNPs) were produced both by chemical and green routes. For that, yerba mate tea was chosen as reducing and stabilizing agent of the green synthesis. The chemical synthesis were accomplished according to the available literature. Also, minimum inhibitory concentration assays of the nanoparticles against the Gram-negative bacteria Escherichia coli and the Gram-positive bacteria Staphylococcus aureus were performed. There was color change in all the synthesis, indicating nanoparticles formation. AgNPs produced by green route had hydrodynamic diameter (number mean) (HD) values of 30,78 nm, polydispersity index (PdI) of 0,284 and Zeta potential (pZ) of -12,80 mV; chemical AgNPs: HD of 2,28 nm, PdI of 0,526 and Zp of -19,80 mV; FeNPs produced by green route: HD of 1756 nm, PdI of 0,448 and Zp of -11,1 mV; chemical FeNPs: HD of 209,8 nm, PdI of 0,432 and Zp of -41,5 mV; green CuAgNPs: HD of 46,16, PdI of 0,466 and Zp of -25,80 mV; chemical CuAgNPs: HD of 300,9 nm, PdI of 0,505 and Zp of -20,1 mV; finally, green AgFeNPs: HD of 1245 nm, PdI of 0,345 and Zp of +12,1 mV; and chemical AgFeNPs: HD of 722,1 nm, PdI of 0,275 and Zp of -18,5 mV. Regarding to the antimicrobial activity of the nanoparticles, AgNPs produced by green route inhibited E. coli growth in the concentration of 128 µM and of S. aureus in the concentration of 256 µM. None of the other synthesized nanoparticles inhibited bacteria growth in the studies concentrations. In short, monometallic, and bimetallic nanoparticles were synthesized from chemical and green routes, and only one of them presented antimicrobial activity. In this way, it is intend to employ such synthesized NPMs in future studies to evaluate their possible cytotoxic activity using different methodologies, including tests on low-cost devices based on Boyden chambers that will be produced, and to analyze whether the NPMs produced by chemical synthesis have differential toxicity when compared to NPMs produced by green route.

COMMITTEE MEMBERS:
Externa à Instituição - DAIANA SILVA DE AVILA - Unipampa
Externa à Instituição - CINTHIA CAETANO BONATTO - EMBRAPA
Presidente - 1644041 - CLAURE NAIN LUNARDI GOMES
Externa à Instituição - LIVIA CRISTINA DE SOUZA VIOL - ALLES NANO