  Biosensors are essential tools which have been traditionally used to monitor
environmental pollution, detect the presence of toxic elements and biohazardous
bacteria or virus in organic matter and biomolecules for clinical diagnostics.
In the last couple of decades, the scientific community has witnessed their
widespread application in the fields of military, health care, industrial
process control, environmental monitoring, food-quality control, and
microbiology. Biosensor technology has greatly evolved from the in vitro
studies based on the biosensing ability of organic beings to the highly
sophisticated world of nanofabrication enabled miniaturized biosensors. The
incorporation of nanotechnology in the vast field of biosensing has led to the
development of novel sensors and sensing mechanisms, as well as an increase in
the sensitivity and performance of the existing biosensors. Additionally, the
nanoscale dimension further assists the development of sensors for rapid and
simple detection in vivo as well as the ability to probe single-biomolecules
and obtain critical information for their detection and analysis. However, the
major drawbacks of this include, but are not limited to potential toxicities
associated with the unavoidable release of nanoparticles into the environment,
miniaturization induced unreliability, lack of automation, and difficulty of
integrating the nanostructured-based biosensors as well as unreliable
transduction signals from these devices. Although the field of biosensors is
vast, we intend to explore various nanotechnology enabled biosensors as part of
this review article and provide a brief description of their fundamental
working principles and potential applications.
