High Performance Nanostructured Silicon Oxide Impedance Biosensor System with Online Noise Spectroscopy Analysis
In this paper, noise spectroscopy has been reported earlier as an efficient tool for enhancing the selectivity of biosensors and the analysis was carried out by desktop spectrum analyzer. There were no reports, however, on the efficacy of this method in complex mixture. We have performed here for the first time, noise spectroscopy analysis on complex mixture of food toxin samples and observed that the first cut-off frequencies are indicative of the fact whether the solution has only specific antigen, mixture of specific and nonspecific antigen or no specific antigen at all. To realize a portable immunosensor, we have developed an electronic interface using digital signal processor (DSP) chip of Microchip Technology which has the embedded Fast Fourier Transform (FFT) algorithm for computation of noise spectrum. The entire system has been successfully demonstrated to detect 0.1 fg/ml aflatoxin B1 (AfB1) from a complex mixture with as high as 1000ng/ml non-specific toxins.