Ultra-sensitive cholesterol biosensor based on low-temperature grown ZnO nanoparticles

A high-sensitive cholesterol amperometric biosensor based on the immobilization of cholesterol oxidase (ChOx) onto the ZnO nanoparticles has been fabricated which shows a very high and reproducible sensitivity of 23.7 mu A mM(-1) cm(-2), detection limit (based on S/N ratio) 0.37 +/- 0.02 nM, response time less than 5 s, linear range from 1.0 to 500.0 nM and correlation coefficient of R = 0.9975. A relatively low value of enzyme's kinetic parameter (Michaelis-Menten constant) similar to 4.7 mM has been obtained which indicates the enhanced enzymatic affinity of ChOx to Cholesterol. To the best of our knowledge, this is the first report in which such a very high-sensitivity and low detection limit has been achieved for the cholesterol biosensor by using Zno nanostructures modified electrodes. (c) 2008 Elsevier B.V. All rights reserved.