Nanostructured nickel oxide-chitosan film for application to cholesterol sensor

Cholesterol oxidase (ChOx) physisorbed onto NiO nanoparticles (nNiO, 22 nm)-chitosan (CHIT) film prepared using coprecipitation method has been characterized using x-ray diffraction, Fourier transform infrared, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy techniques. The results of electrochemical response studies conducted on ChOx/nan-NiO-CHIT/ITO bioelectrode show linearity of 10-400 mg/dl, detection limit of 43.4 mg/dl, sensitivity of 0.808 mu A/ (mg dl cm(2)), fast response time of 15 s, and shelf-life of about 10 weeks. The low value of Michaelis-Menten constant (K(m)) obtained as 0.67 mM indicates high affinity of ChOx toward the substrate. (C) 2011 American Institute of Physics. [doi:10.1063/1.3553765]