Realization of an efficient cholesterol biosensor using ZnO nanostructured thin film

A zinc oxide (ZnO) nanostructured thin film synthesized by a vapour phase transport technique on a platinum coated silicon (Pt/Si) substrate has been successfully utilized for the detection of cholesterol. Amperometric and photometric studies reveal that the prepared bioelectrode ChOx/ZnO/Pt/Si is highly sensitive to the detection of cholesterol over a wide concentration range, 0.12–12.93 mM (5–500 mg dl−1). The higher sensitivity is attributed to the large surface area of ZnO thin film for effective loading of ChOx besides its high electron communication capability. A relatively low value of the enzyme's kinetic parameter (Michaelis–Menten constant, 1.08 mM) indicates an enhanced affinity of the enzyme (ChOx) towards the analyte (cholesterol). The prepared bioelectrode is found to exhibit a long shelf life of more than 10 weeks, having negligible interference from the presence of other biomolecules present in human serum indicating potential application of the ZnO nanostructured thin film for cholesterol sensing.