| Summary: | 碩士 === 中山醫學大學 === 醫學檢驗暨生物技術學系碩士班 === 100 === Impedance spectroscopy has become the main research topic in the development of biosensor due to the advantages of rapid diagnosis, faster detection time and high sensitivity. Through direct measurement of impedance telecommunications allows the replacement of traditional biochemical tests. C-reactive protein is an inflammatory marker believed to be of value in the prediction of coronary events. The purpose of this study is to develop a highly selective and specific impedance biosensor for CRP detection. A silver-carbon electrode was prepared by screen printing method, namely screen-printed electrode (SPE). The electrode was then immersed in benzene-derived compounds such as hydrocinnamic acid, 2-phenylethanethiol or phenethylamine solution, followed by immobilization of anti-CRP antibody on the surface of electrode via covalent bonding with cross-linking agen. SEM observation showed that the surface of SPE became rough after treated with anti-CRP, indicating that the electrode had been successfully modified. Element content analysis showed that sulphur, nitrogen and oxygen was specifically recognized on the surface of SPE. The SPE has grafting rate of about 80% when connected with anti-CRP antibody. The measurement of cyclic voltammetry (CV) showed that benzene-derived modified SPE would have enhanced sensor sensitivity. Electrochemical impedance spectroscopy (EIS) showed that protein CRP would hindered the electron transfer on the surface of SPE and lead to higher impedance, which proved that the electrode has high binding affinity of CRP. Using benzene-derived compounds as the mediator could increase the electroactive area and the amount of immobilized biomolecules. The SPE system we designed has the potential to develop into biosensors.
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