Biocatalytic sensors are devices which consist of bioactive functionally grafted
layers of catalysts or analytical pieces which are in contact with transducers
that help to convert biological signals into electrical pulses. They are
essentially distinct materials whose design, application, immobilization, and
transducing capacities induce/infuse distinct properties that offer several
advantages in science, engineering, and medicine. The essentiality of
biocatalytic sensors cannot be overemphasized; however, for successful
application, it is necessary to understand their origins, nature, mechanism of
operation, as well as their behavioral activities in different media within
favorable conditions. Hence, three categories of biosensors, whose
mechanisms of operation would be discussed include the biocatalytic, bioaffinity, and microbial groups. In addition, the synthesis and mechanisms of
immune, DNA, thermal, and piezoelectric biosensors, will be discussed in
relation to their indispensable functionalities in multitudinous facets, such as
the food industry, where quality checks are conducted to detect poisonous
substances and glucose levels, in metabolic engineering, where in vivo
assessments and monitoring of cell responses to metabolism are carried out
and in medicine, where drugs, heart diseases, and the human papilloma virus
can be X-rayed; biosensors also find application in defense/military
technology and marine science, just to mention a few. In today’s world, a
myriad of biosensors, assume the form of membrane-bound
microorganisms/enzymes, antibodies, receptors, or multilayered (matrixenzyme)
nanocomposites, all geared towards the maximization of the
synergistic effect which these combinations offer in order to advance
humanity. With the advent of newly discovered hyperthermophiles, it would
be an interesting thing to consider their usage in biosensing especially at
temperatures that can sometimes be twice above 50 °C, which may be
unfavorable for most enzymes. However, the potentials of these biosensors
are yet to be exploited maximally owing to the dearth in the understanding of
the basic principles underlying the conditions within which they work best. To
effectively optimize the potentials/performances of biosensors, a good
understanding of the nature/characteristics of such systems, the principle on which they operate alongside the system’s pH, temperature, and type of
medium, which either favor or mare their activities are required. Hence, this
chapter’s discourse will essentially focus on the mechanisms and modes of
operation of existing biosensors as well as recent/futuristic applications of
potential bioactive materials, anchored on graphene and other potential
substrates
