Banca de DEFESA: LUCAS COSTA FAUSTINO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: LUCAS COSTA FAUSTINO
DATA: 31/01/2023
HORA: 08:30
LOCAL: Modalidade Híbrida Local: Auditório do PPGQ-UFPI /Google Meet (meet.google.com/qte-bxvj-gav)
TÍTULO: 3D-printed pencil holder: a machine-free fabrication strategy toward highly reproducible pencil-drawn paper-based electrodes
PALAVRAS-CHAVES: 3D printing, pencil drawn, pen-on-paper, electrochemical sensors, point-of-care devices
PÁGINAS: 20
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Físico-Química
ESPECIALIDADE: Eletroquímica
RESUMO:

Pencil drawing is one of the simplest and cost-effective ways of fabricating miniaturized electrodes on paper substrate through solid transfer of graphite by rubbing, but that lacks reproducibility regarding the electrode drawing process. A 3D-printed pencil holder (3DPH) is proposed here for simple, reproducible, and low-cost hand-drawn fabrication of paper-based electrochemical devices (PEDs). The 3DPH is designed to maintain the same pressure and angulation of the graphite mine on the paper substrate using a micromechanical pencil regardless of the operator, significantly improving the reproducibility and cost of making reliable PEDs. In addition, a 3D electrochemical cell designed for simple and agile application of pencil-drawn electrodes is also presented. The results showed high reproducibility and accuracy of the 3DPH-assisted electrodes prepared by 4 different operators in terms of sheet resistance and electrochemical behavior. Cyclic voltammetric curves in presence of [Fe(CN)₆]^3-/4- redox probe shown only 3.9% variation for the anodic peak currents of different electrodes prepared by different operators when compared to electrodes prepared without the 3D printed support. The improvement in reproducibility was corroborated and better understood from SEM analyses, in which revealed a more uniform graphite deposition/design of the electrodes prepared with 3DPH. As a proof of concept, 3DPH-assisted pencil-drawn graphite electrodes were employed for dopamine detection in synthetic saliva, showing a proportional increase in anode peak current with increasing DA concentration from 10 µmol L^-1 to 200 µmol L^-1, with a detection limit of 0.14 µmol L^-1. Finally, we believe that this approach can make pencil-drawn technology more accurate, reproducible, robust, accessible, reliable, and inexpensive for real on-site applications, especially in hard-to-reach locations or research centers with little investment.

MEMBROS DA BANCA:
Presidente - 1998602 - EVERSON THIAGO SANTOS GERONCIO DA SILVA
Interno - 794.918.553-87 - REGINALDO DA SILVA SANTOS - UESPI
Interno - 2406262 - ROBERTO ALVES DE SOUSA LUZ
Externo à Instituição - MURILO SANTHIAGO - CNPEM
Externo à Instituição - WENDELL KARLOS TOMAZELLI COLTRO - UFG