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

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 degrees C, when polarized at +0.4V against Ag/AgCl. There was a linear relationship between sensor response and triolein concentration in the range 50-700 mg/dl with sensitivity of 0.05 mu A/mg/dl. The sensor was employed for determination of TG in serum. The detection limit of the biosensor was 10 mg/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 degrees C. (c) 2013 Elsevier B.V. All rights reserved.