Highly sensitive photonic crystal based biosensor for Bacillus cereus

The Bacillus cereus or B. cereus group comprises genetically closely related species with variable toxigenic characteristics. Most human food poisoning is caused by B. cereus. B. cereus is associated with nosocomial and opportunistic infections, particularly in immunocompromised patients. The motivation for this work was to provide an alternate method of detection of B. cereus on the fly. The purpose of the current study is to establish an innovative method to detect B. cereus. The proposed technique relies on a change in refractive index (RI) between normal and B. cereus infected blood. This involves the spectral analysis of the sample and uses the unique RI of the bacteria as a spectral signature for detection. The design incorporates an optical biosensor based on the photonic crystal (PC). Here we have considered two configurations—concentric and the side by side hexagonal ring resonators for PC based biosensor design. We have observed the shift in the frequency of the spectrum between normal and infected blood. From the plotted transmission spectrum, we conclude that there is a significant shift in frequency because of the change in RI due to infection. For the designed biosensors the ranges of Quality factors obtained are between 722 to 1626.31 and Sensitivity 1.0845 µm/RIU to 375.5 µm/RIU. This concludes that we can use B. cereus infected blood specific transmission spectra as a signature to match unknown blood sample to detect B. cereus.