Construction of triglyceride biosensor based on nickel oxide–chitosan/zinc oxide/zinc hexacyanoferrate film

Abstract

A method is described for construction of an amperometric triglyceride (TG) biosensor based on co-immobilization of lipase, glycerol kinase (GK) and glycerol-3-phosphate oxidase (GPO) onto nickel oxide nanoparticles (NiONPs)–chitosan (CHIT) nanocomposite adsorbed onto zinc oxide/zinc hexacyanoferrate (ZnO–ZnHCF) hybrid film electrodeposited on the surface of an Au electrode. The NiONPs–CHIT/ZnO–ZnHCF hybrid film was characterized by cyclic voltammetry (CV), atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The biosensor showed optimum response within 4s at pH 6.0 and 35°C, when polarized at +0.4V against Ag/AgCl. There was a linear relationship between sensor response and triolein concentration in the range 50–700mg/dl with sensitivity of 0.05μA/mg/dl. The sensor was employed for determination of TG in serum. The detection limit of the biosensor was 10mg/dl. The biosensor was evaluated with 95–96% recovery of added triolein in sera and 2% and 3% within and between batch coefficients of variation (CVs) respectively. There was a good correlation (r=0.99) between serum TG values by standard enzymic colorimetric method and the present method. The biosensor lost 50% of its initial activity after its 100 uses over a period of 180 days, when stored at 4°C.