Figure 2: Schematic representation of working of biosensor
Bioreceptors are the biocatalytic molecule including enzymes, cells,
antibodies, nucleic acids, and microbes that recognizes the analyte.
According to the bioreceptors component, biosensors will be classified
into DNA biosensors, enzymatic biosensors, non-enzymatic biosensors and
immunosensors, and whole-cell biosensors. Enzymatic biosensors are the
one which combines enzyme with transducer. The specific immobilized
enzyme identifies a specific substrate and produces a signal, the
substrate can be identified by any of the transducers (optical,
electrochemical, thermal and Piezoelectric) and converted into electric
signal. The non-enzymatic biosensor has metal like platinum integrated
with a transducer. Non-enzymatic sensors are without biological
functional units and can be beneficial in terms of structural simplicity
and mass production (Mehrotra, 2016).
Immunosensors are selective, specific, and flexible biosensors that
recognize a stable compound of particular antigens or antibodies. DNA
biosensors are categorized by spontaneous hydrogen bonding of the target
DNA with its complementary strand based on the detection of nucleic acid
sequences from infectious microbes and tiny contaminants (Asal et al.,
2018).
Whole-cell biosensors are those that use living organisms as the
recognition component, such as bacteria, yeast, fungus, plant and animal
cells, or even tissue slices, by monitoring the initial inputs into a
biological response. Whole-cell biosensors have an advantage of
providing sensitive, selective, real-time, rapid and unique data as
compared to conventional chemical-based biosensors. A marine algaeSpirulina subsala has an application in detecting metals and
pesticides (Tonnina et al., 2002). As biosensors are cost-effective and
sensitive, their applications have increased rapidly in environment,
medical and industrial applications (Anand Raj et al., 2020).