Biossensores autónomos e auto-indicados para biomarcadores de cancro

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Biossensores autónomos e auto-indicados para biomarcadores de cancro

Terça, 30.07.2019
Os biossensores electroquímicos permitem a monitorização no ponto de cuidado de biomarcadores do cancro, uma abordagem que é especialmente relevante no contexto de programas de rastreio, tendo em vista a detecção precoce do cancro. No entanto, estes dispositivos requerem uma fonte de energia e um sistema electrónico de medida, que favoravelmente poderiam ser dispensados. Este trabalho descreve por isso a integração de sensores electroquímicos num sistema fotovoltaico (fonte de energia), combinados com um sistema de detecção electrocrómico (sinalização corada da resposta).

Autores e Afiliações:
Ana Tavares, Liliana Truta, Felismina Moreira, Liliana Carneiro, Goreti Sales
BioMark sensor research, Instituto Superior de Engenharia do Porto
CEB, Centro de Engenharia Biológica, Universidade do Minho
 
Abstract:
This work describes a novel and disruptive electrochemical biosensing device that is self-powered by light and self-signalled by an optical readout. Electrical energy requirements are ensured by a photovoltaic cell that is a dye sensitized solar cell (DSSC), in which one of the electrodes is the biosensing unit. The readout converts electrical energy into colour by an electrochromic cell and signals the concentration dependent event. This device was designed to target a cancer biomarker, cancinoembryonic antigen (CEA).
In brief, the sensing unit was assembled on a conductive glass substrate with a highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) layer, using a molecularly-imprinted polymer of polypyrrol (PPy) as biorecognition element. This sensing unit acted as the counter electrode (CE) of the DSSC, generating a hybrid device with a maximum power conversion efficiency of 10.36 % for a photoanode area of 0.2 cm2. The hybrid DSSC/biosensor had an electrical output that was CEA concentration dependent from 100 ng/mL to 100 µg/mL, with a limit detection of 0.14 ng/mL in human urine samples. The electrochromic cell consisted of a PEDOT-based material and showed a colour gradient change for CEA concentrations, ranging from 0.1 ng/mL to 100 µg/mL.
Overall, this self-powered and self-signalled set-up is equipment free and particularly suitable for point-of-care analysis (POC), being able to screen CEA in real samples and differentiating critical concentrations for establishing a diagnosis. It holds the potential to provide clinical relevant data anywhere, in a fully independent manner.
 
Revista: Biosensors and Bioelectronics