Nanocrystalline bioactive TiO2-chitosan impedimetric immunosensor for ochratoxin-A

Fourier transform infrared (FT-IR) and UV-visible spectroscopy were used to optimize TiO2 concentration in chitosan (CS) to develop a sensitive CS/TiO2 bioactive electrode. Electrochemical impedance spectroscopy (EIS) used to measure electro-activity of these bioactive electrodes associated with enhance oligosaccharide containing -C=O groups from degradation of CS molecules. This matrix has free -NH2 and -OH functional groups due to higher probability of hydrogen and covalent bonding between -OH group in CS molecules with Ti-O-Ti which supported immobilization of rabbit antibodies (IgGs) and proteins. Ochratoxin A (OTA) was detected and showed a linear response up to 10 ng/mL with CS/TiO2 bio-electrode. The OTA detection sensitivity of 7.5 mM TiO2 added CS bioactive electrode was four times higher than only CS. (c) 2008 Elsevier B.V. All rights reserved.