Sensitive optical biosensor based on surface plasmon resonance using ZnO/Au bilayered structure

The present article represents the preparation of highly sensitive optical biosensor using an indigenously assembled table top Surface plasmon resonance (SPR) technique. Surface plasmon modes have been excited at the ZnO-gold interface exploiting Kretschmann configuration. RF-magnetron sputtering has been utilised to deposit ZnO thin films further used for the immobilization of specific enzyme GOx by physical adsorption technique. The SPR reflectance curves were recorded for the GOx/ZnO/Au/prism system in angular interrogation mode in Phosphate buffer saline (PBS) solution by varying analyte (glucose) concentration from 0 mg/dl to 300 mg/dl. The transient variation in the intensity of reflectance (i.e. response) at fixed SPR resonance angle for increasing concentration of glucose is also reported. The prepared sensor exhibits enhanced response (0.75 for 25 mg/dl) with high specificity and good linearity beyond the physiological range indicating the realization of an efficient optical biosensor.