A sensitive electrochemiluminescent cholesterol biosensor based on Au/hollowed-TiO2 nano-composite pre-functionalized electrode

This paper describes a novel approach to promote the analytical performance of electrochemiluminescent (ECL) biosensor of cholesterol by a nanocomposite (Au nanoparticles/ion liquid/hollowed TiO2 nano-shell) pre-functionalized indium tin oxide glass to load the cholesterol oxidase. Here the enzymatically produced hydrogen peroxide greatly intensified the ECL of luminol under the catalysis of the nanocomposite. The quantification of cholesterol was directly accomplished by calibrating the ECL sensing output. The formation and properties of the nanocomposite and the functionalized electrode have been confirmed by electrochemistry, spectroscopy and electron-microscopy. The prepared biosensor exhibits a linear regression ranged from 8.33 × 10−9 M to 4.17 × 10−7 M with an ultralow detection limit (LOD) of 6.30 × 10−9 M. It also possesses the excellent specificity for cholesterol from potential interferents, the favorable repeatability/stability for use or storage, the good reproducibility and adequate recovery for real sample test. In addition, for the detection of clinical serum sample, it is well consistent with the datum from medical cholesterol kit, indicating its reliability. It is in promising of the application for the cholesterol detection in those clinical specimens of teeny amount of sample and limited concentration.