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Resumo(s)
A determinação da concentração de cobre salivar é importante no diagnóstico clínico, como oligoelemento necessário ao funcionamento fisiológico, e no diagnóstico precoce, tratamento e progresso de doenças pré-malignas e malignas como o cancro da cavidade oral. Neste trabalho é proposto o desenvolvimento de um dispositivo descartável de utilização no local baseado em papel (μPAD) que tem por base conceitos de microfluxo para quantificação imediata de cobre como um potencial biomarcador na saliva humana. Para tal, foram realizados diversos testes no que diz respeito ao estudo da reação do cobre com a batocuproína e à configuração do μPAD com o intuito de obter a melhor sensibilidade. Para além disso, foram efetuados estudos de estabilidade, quer do produto colorido formado, quer do dispositivo em si. O dispositivo desenvolvido apresenta um intervalo de concentrações de 0,080 – 0,500 mg/L, uma curva de calibração de A=0,0705(±3×10-4)×[Cu2+]+8,20×10-4(±4,79×10-4), um limite de deteção de 0,032 mg/L e um limite de quantificação de 0,080 mg/L. No que diz respeito à estabilidade, o μPAD mostrou-se estável quando armazenado em vácuo por um período de pelo menos duas semanas e, após a colocação da amostra, a leitura do produto colorido formado pode ser feita entre os 20 e os 90 minutos sem que a sensibilidade do método seja afetada. O dispositivo desenvolvido é descartável, económico (0,32€/μPAD), rápido e simples. Além disso, sendo o cancro oral a neoplasia mais comum nos países em desenvolvimento, a portabilidade do μPAD é ideal. A exatidão do método desenvolvido foi avaliada com amostras de águas certificadas uma vez que não se conseguiu avaliar com amostras de saliva, possivelmente devido ao facto de a saliva ser um fluido biológico que tem na sua constituição proteínas que podem interferir. Logo, é necessário realizar mais estudos para otimizar o método e permitir a sua utilização com saliva de pacientes.
The determination of salivary copper concentration is important in clinical diagnosis, trace element necessary for physiological functioning, and early diagnosis, treatment and progress of premalignant and malignant diseases such as oral cavity cancer. In this work, the development of a disposable paper-based device (μPAD) for on-site use based on microflow concepts for immediate copper quantification as a potential biomarker in human saliva is proposed. For this purpose, several tests were carried out regarding the study of the reaction of copper with bathocuproine and the design of μPAD in order to obtain the best sensitivity. In addition, stability studies were performed on both, the colored product formed and the device itself. For the concentration range of 0.080 – 0.500 mg/L, the developed device presents the following characteristics: a calibration curve of A=0.0705(±3×10-4)×[Cu2+]+8.20×10-4 (±4.79×10-4), a detection limit of 0.032 mg/L and a quantification limit of 0.080 mg/L. Regarding stability, μPAD was stable when stored under vacuum for a period of at least two weeks and, after sample placement, the color product formed could be read from 20 to 90 minutes, without the sensitivity of the method being affected. The developed μPAD device is disposable, economical (0.32€/μPAD), quick and simple. In addition, μPAD portability is ideal because oral cancer is the most common cancer in developing countries. The accuracy of the developed method was evaluated with certified water samples as it could not be evaluated with saliva samples, possibly due to the fact that saliva is a biological fluid that has interfering proteins in its constitution. Thus, further studies are needed to optimize the method and allow its use with patient saliva.
The determination of salivary copper concentration is important in clinical diagnosis, trace element necessary for physiological functioning, and early diagnosis, treatment and progress of premalignant and malignant diseases such as oral cavity cancer. In this work, the development of a disposable paper-based device (μPAD) for on-site use based on microflow concepts for immediate copper quantification as a potential biomarker in human saliva is proposed. For this purpose, several tests were carried out regarding the study of the reaction of copper with bathocuproine and the design of μPAD in order to obtain the best sensitivity. In addition, stability studies were performed on both, the colored product formed and the device itself. For the concentration range of 0.080 – 0.500 mg/L, the developed device presents the following characteristics: a calibration curve of A=0.0705(±3×10-4)×[Cu2+]+8.20×10-4 (±4.79×10-4), a detection limit of 0.032 mg/L and a quantification limit of 0.080 mg/L. Regarding stability, μPAD was stable when stored under vacuum for a period of at least two weeks and, after sample placement, the color product formed could be read from 20 to 90 minutes, without the sensitivity of the method being affected. The developed μPAD device is disposable, economical (0.32€/μPAD), quick and simple. In addition, μPAD portability is ideal because oral cancer is the most common cancer in developing countries. The accuracy of the developed method was evaluated with certified water samples as it could not be evaluated with saliva samples, possibly due to the fact that saliva is a biological fluid that has interfering proteins in its constitution. Thus, further studies are needed to optimize the method and allow its use with patient saliva.
Descrição
Palavras-chave
Cancro oral Cobre Saliva μPAD Batocuproína Oral cancer Copper Bathocuproine