Superoxide Anion Radical Sensor Using GC Electrode Modified with Heparin/PEDOT and Polymerized Iron Porphyrin

Abstract

Blood coagulation on the electrode surface is a serious problem for a superoxide anion radical (O2−∙) sensor because it causes deterioration of the current signal especially in vivo. In order to solve this problem, we have developed iron porphyrin-based O2−∙ sensors immobilizing heparin, which is an anti-thrombotic compound, on the surface. In the present study, we immobilized heparin with a polyethylenedioxythiophene (PEDOT) matrix on poly[iron tetrakis(3-thienyl)porphyrin]-modified glassy carbon (GC) electrode, and the stability of the modified sensor to blood coagulation was investigated. The PEDOT matrix was found to be more effective for stable electrochemical detection of O2−∙ after immersion in a fibrinogen/thrombin solution for two weeks, while serious electrode fouling due to blood clot formation was occurred at a sensor using a polypyrrole matrix after immersion in the solution for one week.