Banca de DEFESA: GILSON PEDRO LOPES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : GILSON PEDRO LOPES
DATE: 14/09/2022
TIME: 09:00
LOCAL: Por participação remota
TITLE:

Glucose 0xidase-functionalized Nd_1-xEu_xNiO₃ thin films for glucose detection 

PAGES: 80
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUBÁREA: Materiais Não-Metálicos
SPECIALTY: Cerâmicos
SUMMARY:

Glucose is an essential compound for human body, which are directly related to metabolic processes. Therefore, its control is important for disease control and monitoring of metabolic processes. The literature describes several materials and composites for the construction of glucose biosensors. Among these, the family of oxides RNiO₃, (R=rare earth) has been studied because they have characteristics that are interesting for several applications involving biosensors, catalysis, electronic devices, etc. These oxides (R ≠ La) crystallize in the orthorhombically distorted perovskite structure with different physical properties, such as the presence of a metal-insulator transition that can be modulated by doping, lattice voltage and introduction of defects. In this work, the sensitivity of the transport properties of Nd_1-xEu_xNiO₃ films (x=0; 0.30; 0.35) functionalized with GOx enzymes (Glucose Oxidase) to the presence of glucose was investigated. The films were prepared by chemical solution deposition, X-ray diffraction characterizations show the presence of the desired crystalline phase. Scanning electron microscopy images reveal a homogeneous and crack-free surface microstructure, with thicknesses of the order of 320nm. Preliminary measurements of electrical resistivity versus temperature in the films indicate the presence of the MI transition ranging from 200 to 330K for the films with x=0 and 0.35, respectively. For the construction of the biosensors, gold electrodes (~100 nm) were deposited and were functionalized with cysteamine and GOx. Electrical resistance measurements at room temperature were used to monitor the interaction of glucose on these films. Films with x=0 and 0.35 showed an expressive response to the presence of glucose even at concentrations of the order of 10^-12 ML^-1. Interference, selectivity, repeatability, and reproducibility of the results were evaluated. The introduction of Eu³⁺ in the NdNiO₃ matrix modifies its electronic structure, this seems to have a direct relationship with the sensing response of these devices, in fact the literature describes the reaction mechanism as dependent on the Ni³⁺/Ni²⁺ ratio and the T_MI values in nickelates. Preliminary results suggest that these compounds may be excellent candidates for the construction of glucose biosensors.

BANKING MEMBERS:
Presidente - Interno ao Programa - 1545738 - MARCIA TSUYAMA ESCOTE
Membro Titular - Examinador(a) Interno ao Programa - 1676364 - JULIANA MARCHI
Membro Titular - Examinador(a) Externo à Instituição - FABIANA VILLELA DA MOTTA - UFRN
Membro Suplente - Examinador(a) Interno ao Programa - 1545089 - DANIEL ZANETTI DE FLORIO
Membro Suplente - Examinador(a) Externo ao Programa - 1768304 - DENISE CRIADO PEREIRA DE SOUZA