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.