3.3.2 Biosilica based biosensors:
Diatom frustules are composed of nanostructured amorphous silica, and their surface may be functionalized and tailored for biosensor applications. Due to the easy availability of diatom frustules in every pond water, it assures its low cost. Rea & De Stefano, (2019) reported the fabrication of silver nanoparticles on the diatom surface, which produces huge plasmonic hotspots that increase the Raman effect. The molecular probes are covalently attached to the diatom cell wall (DNA strands, proteins, enzymes, antibodies, and so on). Selvaraj et al. (2018) found that nitroaromatic compounds could be identified with excellent sensitivity and specificity using amine-removed diatom frustules from Nitzschia sp They also reported the detection ofSalmonella typhi by same diatomic species. Leonardo et al. (2017) reported fixation of antibody functionalized diatoms on gold electrodes. Changing the electrodeposition parameters can influence diatom immobilization, orientation, and yield. For methyl parathion electrochemical detection, Gannavarapu et al. (2019) utilized a diatomPhaeodactylum tricornutum surface reformed by ZrO2 by precipitating in a solution. The hybrid diatom-based electrode offers the benefit of detecting pollutants, chemicals, and enzymes at the picomolar level.