Multi-Parametric Optical Glucose Sensor Based on Surface Functionalized Nano-Porous Silicon

In this paper, a multi-parametric optical glucose sensor based on nano-structured porous silicon (PSi) has been reported. The surface of the nano-PSi has been functionalized by physisorption of glucose oxidase for selective detection of glucose molecules. Multiple optical parameters, such as specular reflectance, scattering due to diffuse reflection, and absorption loss, have been measured from a single reflected image of a white light from the sensor surface in presence and absence of glucose through image processing software. The results indicate that specular reflectance decreases and scattering and absorption loss increase with increasing glucose concentration in aqueous solution. Reliable results were obtained in the range of 1-30 mM (18-540 mg/dl) glucose solution and limit of detection was found to be 0.33 mM (6 mg/dl). The sensor shows high reproducibility, good response, and high sensitivity. Moreover, the multi-parametric approach makes it potentially more selective and enhances the overall sensitivity.