Comparison of thiol and dithiol monolayer modification on screen-printed electrode in capacitive immunosensor for detection of human serum albumin

• Main Authors: Chen-Wei Chang, 張建偉
• Other Authors: 劉永銓
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/89225615872439321168

碩士 === 國立中興大學 === 化學工程學系所 === 98 === Fabrication of a novel capacitive immunosensor based on self-assembled monolayer (SAM) incorporated with gold nanoparticles on a screen-printed thick-film electrode was the first time built for the detection of human serum albumin (HSA). Anti-HSA was immobilized on gold nanoparticles incorporated to a self-assembled monolayer onto the gold working electrode. Interaction of anti-HSA and HSA was directly detected by the capacitance measurement. The optimal preparation condition for fabricating this HSA immunosensor was studied. The optimized manufacturing reaction conditions were as follows：anti-HSA concentration of 0.5 mg/ml, pH 7.4 immuno binding time of 50 minutes, and the electrolyte concentration of 10 mM. Both thiourea and cysteamine were used to build the capacitive immunosensor. Cysteamine has a better detection range and detection limit. Second. The dithiol monolayer was compared with the thiol monolayer in the immunosensor detection. Experimental results showed that the immunosensor made by cysteamine responded linearly to HSA concentration. The linear detection range for thiol monolayer was in the range of 0.78-800 ng/ml (R=0.994) and dithiol monolayer was in the range of 0.39-1000 ng/ml (R=0.9974). The dithiol monolayer in immunosensor with gold nanoparticles to absorb more antibody displayed an increase in the detection range and detection limit. The capacitive immunosensor is a label-free and real time detection. In the assessment of the potential applications, the developed sensor can be employed for the single use, disposable biosensor in the clinical analysis of HSA.