Development of paper-based biosensor for biomarker detection

Abstract

This dissertation focused on the development of novel biosensor for sensitive determination of biomarkers in biological samples, which can be divided into 2 sections. The first section is the development of sensitive biosensor using graphene-polyaniline nanocomposite. Biomarkers (i.e. cholesterol) and heavy metals (i.e. Zn (II), Cd (II) and Pb (II)) in biological fluids were determined by this proposed biosensor. The second section is active paper chip for electrochemical multiprobe detection of glucose, dopamine and uric acid. Cobalt (II) phthalocyanine, gold nanoparticle and reduced graphene oxide were used to modify the electrode for the improvement of biosensor sensitivity. The experimental parameters in the electrochemical detection were optimized to provide the best condition for biomarker determination. The sensitivity of these developed biosensors was discussed. Moreover, the influence of substrate materials used for making a sensor including paper and plastic film were investigated and optimized. The results showed that paper-based sensor is suitable for biomolecule detection. On the other hand, plastic-based sensor showed a good result for heavy metals detection using square wave anodic stripping voltammetry. In addition, the analytical performances such as linearity, limit of detection and quantitation (LOD and LOQ), reproducibility and accuracy of these biosensors were studied. The selectivity of the developed biosensor was demonstrated for common interferences. The results showed acceptable range of accuracy and precision for biomarker detection. A very low detection limit was observed at 1.0 µM for cholesterol, 0.5 µM for dopamine, 5.0 µM for uric acid, 1.0 ppb for Zn (II) and 0.1 ppb for Pb (II) and Cd (II). Moreover, the developed biosensors were successfully applied to detect the target biomarkers in biological fluid samples such as human serum.