High sensitivity electrochemical cholesterol biosensor based on amplification of ferrocene-tyramine deposition signal induced by RGO-hemin peroxide nano-enzyme

As cholesterol is very intimately linked to the development of many types of cardiovascular diseases, clinical medicine must have a straightforward and precise method for determining total serum cholesterol (TC). Nowadays, enzymatic methods are routinely used in laboratories for the determination of TC, using cholesterol oxidase and esterase reagents for quantitative analysis on fully automated instruments. In this work, an electrochemical biosensor was developed for highly sensitive detection of cholesterol by modified modification of screen-printed carbon electrode (SPCE) and reduction of peroxidase-mimetic catalytic activity of reduced graphene oxide-hemin (RGO-hemin) nano-enzyme. The hydrolysis of cholesterol produced H 2 O 2 when it was subjected to the actions of cholesterol oxidase (CHOD), cholesterol esterase (CHER), and RGO-hemin. In the presence of H 2 O 2 , ferrocene-tyramine (Fc-Tyr) triggers catalytic deposition amplification effect on the SPCE surface, a great deal of electroactive ferrocene marker accumulates on the electrode surface, and Fc-Tyr is measured by an electrochemical workstation. The redox electrical signal detects the concentration of cholesterol in the sample. The biosensor had an operating range of 0.1∼5 mg/mL and a sensitivity of 24.43 μg/mL with acceptable specificity. The electrochemical cholesterol biosensor sensitively captured cholesterol signals in a complex body fluid environment and showed results consistent with clinical trials, with 96.63∼107.32 % recovery and 0.78∼5.28 % relative standard deviation (RSD). Therefore, there is a significant chance that the cholesterol biosensor by the institute will be used in clinical settings to detect serum cholesterol.