Performance-enhanced cholesterol biosensor based on biocomposite system: Layered double hydroxides-chitosan

Using layered double hydroxides (LDHs)-chitosan (Chit) composite as enzyme immobilization matrix, the developments of cholesterol biosensor were achieved by both electrooxidation and electroreduction of the enzymatic-generated hydrogen peroxide based on cholesterol oxidase (ChOx) and horseradish peroxidase (HRP). Amperometric detection of cholesterol was evaluated by holding the modified electrode at 0.55 V and 0 V (vs. SCE), for ChOx/LDHs-Chit/Pt and ChOx/HRP/LDHs-Chit/GCE, respectively. The linear dynamic ranges of anodic and cathodic detections of cholesterol were between 5 × 10−7 to 8 × 10−4 M and 4 × 10−8 to 6 × 10−4 M, respectively. The detection limits were determined to be of 1 × 10−7 and 4 × 10−8 M with anodic and cathodic processes, respectively. At potential of 0 V, ChOx/HRP/LDHs-Chit/GCE bienzymatic mediated system exhibited excellent selectivity and stability.

► Layered double hydroxides (LDHs)-chitosan (Chit) composite as enzyme immobilization matrix.
► Two cholesterol sensors were constructed by immobilizing cholesterol oxidase and horseradish peroxidase.
► Different cholesterol detections based on electro-oxidation/reduction of enzymatic-generated H2O2.