A nano-composite based biosensor for cholesterol determination

چکیده مقاله

An electrochemical biosensor was prepared by immobilizing cholesterol oxidase (ChOx) on a nanocomposite consisting of amine functionalized multi-walled carbon nanotubes and a room temperature ionic-liquid (1-butyl-3-methylimidazolium tetrafluoroborate). The biosensor was examined for cholesterol quantification in clinical serum samples. ChOx on the modified electrode exhibited a couple of quasi-reversible redox peaks corresponding to the direct electron transfer of FAD/ FADH2 buried in the enzyme structure. A formal potential of 400 mV was obtained for the immobilized enzyme in phosphate buffer solution (0.1 M, pH 7.4). Under the optimized experimental conditions, the biosensor exhibited a linear response towards cholesterol concentration from 26 nM to 3.4 mM, with a sensitivity of 540 mA mM 1and a detection limit of 12 nM.