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Authors
Advisor(s)
Abstract(s)
As doenças cardiovasculares (DCVs) integram um conjunto de patologias, entre as quais se destaca
o enfarte agudo do miocárdio (AMI, do inglês, Acute Myocardial Infarction). As DCVs são a principal
causa de morte no mundo e de morbilidade na Europa. Deste modo, é fundamental melhorar os
métodos de diagnóstico do AMI, para que sejam eficientes, rápidos, precisos e simples, diminuindo
a mortalidade associada a esta doença.
O desenvolvimento de novos biossensores tem vindo a crescer nos últimos anos, com especial
ênfase no diagnóstico de diversas doenças. No presente trabalho, foi desenvolvido um biossensor
eletroquímico para o diagnóstico do AMI, caracterizado por ser de baixo custo, simples e rápido.
Durante a construção deste material biomimético, o analito utilizado foi a mioglobina (Myo), uma
vez que é um biomarcador cardíaco crítico para o diagnóstico de DCVs, tornando essencial a sua
monitorização no local de prestação de cuidados (PoC, do inglês, Point of Care).
O material de suporte utilizado para o desenvolvimento deste biossensor consiste num elétrodo
impresso de platina (Pt-SPE, do inglês, Screen-Printed Platinum Electrodes). Foram adicionados
nanocubos de Prussian Blue (PBNCs) sobre a superfície de Pt-SPE e em seguida, realizou-se a
eletropolimerização (ELP) da orto-fenilenodiamina (o-PD, do inglês, ortho-phenyldiamine) na
presença da Myo através da técnica de voltametria cíclica (CV, do inglês, Cyclic Voltammetry). A ELP
foi realizada na gama de potencial de -0,2 V a +0,8 V, durante cinco ciclos a uma velocidade de 50
mV/s. Após a formação do polímero, o biossensor foi incubado a 37 °C numa estufa, com uma
solução de tripsina durante a noite, resultando na formação de cavidades impressas compatíveis
com o analito-alvo (Myo).
As propriedades estruturais e morfológicas do material foram analisadas através da microscopia
eletrónica de varrimento (SEM, do inglês, Scanning Electron Microscopy) e espectroscopia no
infravermelho por transformada de Fourier (FTIR, do inglês, Fourier transform infrared
spectroscopy). A capacidade do material para religar a Myo foi avaliada através da técnica
eletroquímica de voltametria de onda quadrada (SWV, do inglês, Square Wave Voltammetry).
Nestes ensaios, os dispositivos sensores desenvolvidos apresentaram respostas lineares na gama de
concentração entre 1x10-5 e 1x10+5 ng/mL. Também foi utilizada a técnica de voltametria de pulso
diferencial (DPV, do inglês, Differential Pulse Voltammetry) para avaliar, novamente, a capacidade
do material se ligar à Myo mas livre da solução redox.
Em contraste com as estratégias convencionais de biossensores, que requerem uma solução redox
externa para avaliar o sinal, a configuração desenvolvida ao longo deste estudo permite monitorizar
as alterações de corrente de forma direta e simples, sem a necessidade de introduzir uma solução
redox. O sensor descrito no presente trabalho é uma potencial ferramenta para a triagem PoC de
Myo, visto que é fácil de fabricar e de descartar, apresenta uma resposta rápida, é barato e possui
boa sensibilidade e seletividade.
Cardiac diseases (DCVs) are part of a group of pathologies, particularly acute myocardical infarction (AMI). DCVs are the leading cause of death worldwide and a major cause of morbidity in Europe. Therefore, it is crucial to improve AMI diagnostic methods to make them efficient, rapid, accurate and simple, thereby reducing mortality from this disease. The development of new biosensors has been growing in recent years, with special emphasis on the diagnosis of multiple diseases. In the present work, an electrochemical biosensor was developed for the diagnosis of AMI, characterized by being low-cost, simple, and fast. During the construction of this biomimetic material, the target molecule used was myoglobin (Myo), as it is a critical cardiac biomarker for the diagnosis of DCV, making its monitoring at the point of care (PoC) essential. The support material used for this biosensor was a platinum screen printed electrode (Pt-SEP). Prussian Blue nanocubes (PBNCs) were added onto the Pt-SPE through drop casting and afterwards, electropolymerization (ELP) of ortho-phenylenediamine (o-PD) was carried out in the presence of Myo using cyclic voltammetry (CV). The ELP was performed in a potential range of -0.2 V to +0.8 V, over five cycles at a scan rate of 50 mV/s. After polymer formation, the biosensor was incubated at 37 °C with a trypsin solution overnight, resulting in the formation of printed cavities compatible with the target analyte (Myo). The structural and morphological properties of the material were analysed using scanning electron microscopy (SEM). The material's ability to rebind Myo was assessed using square wave voltammetry (SWV). In these tests, the devices showed linear responses between 1x10-5 and 1x10+5 ng/mL. The differential pulse voltammetry (DPV) was also used to further assess the material's ability to bind Myo, but this time without the redox solution. In contrast to conventional biosensor strategies that require an external redox solution to assess the signal, the developed configuration allows for the monitoring of current changes in the redox-active PBNCs without the redox solution. The sensor described in this study is a potential tool for PoC screening of Myo, as it is easy to fabricate and dispose of, provides a rapid response, is inexpensive, and has good sensitivity and selectivity.
Cardiac diseases (DCVs) are part of a group of pathologies, particularly acute myocardical infarction (AMI). DCVs are the leading cause of death worldwide and a major cause of morbidity in Europe. Therefore, it is crucial to improve AMI diagnostic methods to make them efficient, rapid, accurate and simple, thereby reducing mortality from this disease. The development of new biosensors has been growing in recent years, with special emphasis on the diagnosis of multiple diseases. In the present work, an electrochemical biosensor was developed for the diagnosis of AMI, characterized by being low-cost, simple, and fast. During the construction of this biomimetic material, the target molecule used was myoglobin (Myo), as it is a critical cardiac biomarker for the diagnosis of DCV, making its monitoring at the point of care (PoC) essential. The support material used for this biosensor was a platinum screen printed electrode (Pt-SEP). Prussian Blue nanocubes (PBNCs) were added onto the Pt-SPE through drop casting and afterwards, electropolymerization (ELP) of ortho-phenylenediamine (o-PD) was carried out in the presence of Myo using cyclic voltammetry (CV). The ELP was performed in a potential range of -0.2 V to +0.8 V, over five cycles at a scan rate of 50 mV/s. After polymer formation, the biosensor was incubated at 37 °C with a trypsin solution overnight, resulting in the formation of printed cavities compatible with the target analyte (Myo). The structural and morphological properties of the material were analysed using scanning electron microscopy (SEM). The material's ability to rebind Myo was assessed using square wave voltammetry (SWV). In these tests, the devices showed linear responses between 1x10-5 and 1x10+5 ng/mL. The differential pulse voltammetry (DPV) was also used to further assess the material's ability to bind Myo, but this time without the redox solution. In contrast to conventional biosensor strategies that require an external redox solution to assess the signal, the developed configuration allows for the monitoring of current changes in the redox-active PBNCs without the redox solution. The sensor described in this study is a potential tool for PoC screening of Myo, as it is easy to fabricate and dispose of, provides a rapid response, is inexpensive, and has good sensitivity and selectivity.
Description
Keywords
Surface molecular imprint Prussian blue nanocubes Screen-printed electrodes Cardiac biomarker Myoglobin Liquid redox free Electrochemical Polímeros de impressão molecular Nanocubos de Prussian Blue Eletroquímica Elétrodos impressos Biomarcador cardíaco Mioglobina Deteção direta com redox