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Desenvolvimento de um biossensor eletroquímico à base de nanozimas para deteção de lactato, no contexto da prática desportiva
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Authors
Abstract(s)
O lactato é um importante metabolito do organismo humano, mais conhecido como uma fonte
energética valiosa formada durante o exercício físico. No músculo, o lactato é formado em
condições de falta de oxigénio e, após ser sintetizado, caracteriza-se também por transmitir
informações valiosas sobre a fisiologia corporal. Por este motivo, é monitorizado regularmente
para avaliar o desempenho atlético e apoiar as decisões de treino, prevenindo eventuais lesões.
A deteção de lactato no suor surge como uma alternativa não invasiva à análise sanguínea. No
entanto, os dispositivos de deteção convencionais são complexos, dispendiosos e inadequados
para utilização contínua e em tempo real. Assim, torna-se crucial melhorar os métodos de
monitorização do lactato de forma a que estes sejam rápidos, precisos e também viáveis para
aplicações desportivas.
Os biossensores eletroquímicos surgem como uma nova abordagem, permitindo uma análise
de baixo custo, precisa e em tempo real. No presente estudo, foi desenvolvido um biossensor
eletroquímico modificado com nanoenzimas, mais especificamente nanopartículas magnéticas
de óxido de ferro (Fe₃O₄), otimizado para a deteção de lactato no suor. Para o desenvolvimento
deste biossensor o material de suporte utilizado foi um elétrodo serigrafado impresso de
carbono.
Os elétrodos foram inicialmente modificados com nanopartículas magnéticas e diversos
polímeros, como alginato, Nafion e quitosano. A resposta eletroquímica foi avaliada através da
técnica de voltametria cíclica (CV), utilizando calibrações de lactato em soluções de pH neutro,
alcalino e ácido. O sensor foi otimizado tendo em conta diversos parâmetros, incluindo
concentração das nanopartículas, número de camadas aplicadas no elétrodo, temperatura da
mufla e velocidade de varrimento utilizada nas medições. De seguida, as nanopartículas
magnéticas foram funcionalizadas com β-ciclodextrina, de forma a aumentar a afinidade pelo
analito. Por fim, foram realizados estudos de interferência com outros compostos presentes no
suor, incluindo calibrações de lactato em amostras de suor sintético, de modo a avaliar o
desempenho e o potencial de utilização do sistema em condições reais.
O biossensor otimizado apresentou uma resposta linear no intervalo de concentrações entre
50 μmol/L e 2 mmol/L, com um limite de deteção (LoD) de 7,1 μmol/L e um R² de 0,9988.
Adicionalmente, o sensor demonstrou seletividade na presença de potenciais interferentes do
suor, como a creatinina, a ureia e a glucose, bem como uma boa resposta nos ensaios realizados
em suor sintético.
Este biossensor revelou ser sensível, seletivo e reprodutível para a deteção do lactato no suor,
podendo a sua abordagem ser aplicada em futuras investigações para sistemas de
monitorização contínua.
Lactate is an important metabolite in the human body, best known as a valuable energy source formed during physical exercise. In muscles, lactate is formed in conditions of oxygen deprivation and, after being synthesized, it also transmits valuable information about the body's physiology. For this reason, it is regularly monitored to assess athletic performance and support training decisions, preventing possible injuries. The detection of lactate in sweat emerges as a non-invasive alternative to blood analysis. However, conventional detection devices are complex, expensive, and unsuitable for continuous, real-time use. It is therefore crucial to improve lactate monitoring methods so that they are fast, accurate, and also viable for sports applications. Electrochemical biosensors offer a new approach, enabling low-cost, accurate, real-time analysis. In the present study, an electrochemical biosensor modified with nanoenzymes, more specifically magnetic iron oxide (Fe₃O₄) nanoparticles, was developed and optimized for the detection of lactate in sweat. For the development of this biosensor, the support material used was a screen-printed carbon electrode. The electrodes were initially modified with magnetic nanoparticles and various polymers, such as alginate, Nafion, and chitosan. The electrochemical response was evaluated using cyclic voltammetry (CV), using lactate calibrations in neutral, alkaline, and acidic solutions. The sensor was optimized taking into account several parameters, including nanoparticle concentration, number of layers applied to the electrode, muffle temperature, and scan rate used in the measurements. Next, the magnetic nanoparticles were functionalized with β-cyclodextrin to increase their affinity for the analyte. Finally, interference studies were performed with other compounds present in sweat, including lactate calibrations in synthetic sweat samples, in order to evaluate the performance and potential use of the system under real conditions. The optimized biosensor showed a linear response in the concentration range between 50 μmol/L and 2 mmol/L, with a limit of detection (LoD) of 7.1 μmol/L and an R² of 0.9988. In addition, the sensor demonstrated selectivity in the presence of potential sweat interferents, such as creatinine, urea, and glucose, as well as a good response in tests performed on synthetic sweat. This biosensor proved to be sensitive, selective, and reproducible for the detection of lactate in sweat, and its approach could be applied in future research for continuous monitoring systems.
Lactate is an important metabolite in the human body, best known as a valuable energy source formed during physical exercise. In muscles, lactate is formed in conditions of oxygen deprivation and, after being synthesized, it also transmits valuable information about the body's physiology. For this reason, it is regularly monitored to assess athletic performance and support training decisions, preventing possible injuries. The detection of lactate in sweat emerges as a non-invasive alternative to blood analysis. However, conventional detection devices are complex, expensive, and unsuitable for continuous, real-time use. It is therefore crucial to improve lactate monitoring methods so that they are fast, accurate, and also viable for sports applications. Electrochemical biosensors offer a new approach, enabling low-cost, accurate, real-time analysis. In the present study, an electrochemical biosensor modified with nanoenzymes, more specifically magnetic iron oxide (Fe₃O₄) nanoparticles, was developed and optimized for the detection of lactate in sweat. For the development of this biosensor, the support material used was a screen-printed carbon electrode. The electrodes were initially modified with magnetic nanoparticles and various polymers, such as alginate, Nafion, and chitosan. The electrochemical response was evaluated using cyclic voltammetry (CV), using lactate calibrations in neutral, alkaline, and acidic solutions. The sensor was optimized taking into account several parameters, including nanoparticle concentration, number of layers applied to the electrode, muffle temperature, and scan rate used in the measurements. Next, the magnetic nanoparticles were functionalized with β-cyclodextrin to increase their affinity for the analyte. Finally, interference studies were performed with other compounds present in sweat, including lactate calibrations in synthetic sweat samples, in order to evaluate the performance and potential use of the system under real conditions. The optimized biosensor showed a linear response in the concentration range between 50 μmol/L and 2 mmol/L, with a limit of detection (LoD) of 7.1 μmol/L and an R² of 0.9988. In addition, the sensor demonstrated selectivity in the presence of potential sweat interferents, such as creatinine, urea, and glucose, as well as a good response in tests performed on synthetic sweat. This biosensor proved to be sensitive, selective, and reproducible for the detection of lactate in sweat, and its approach could be applied in future research for continuous monitoring systems.
Description
Keywords
Lactate Biosensor Nanoenzymes Electrochemistry Magnetic iron nanoparticles Sweat Polymers ß -cyclodextrin Lactato Biossensor Nanoenzimas Eletroquímica Nanopartículas magnéticas de ferro Suor Polímeros β-ciclodextrina