other strains was obtained. This no-label approach was easy, rapid, and sensitive for

real-time bacteria detection in environmental samples [46]. Park et al. reported an im­

munosensor for the detection of 2,4,6-Trinitrotoluene (TNT). Herein, they used single-

walled carbon nanotubes in a conducting channel of device, modified with an antibody

against TNT. This could detect TNT in a linear range of 0.5–5,000 ppb. The real water

sample analysis was done and they found that it showed great selectivity towards TNT in

presence of other nitroaromatic explosives [47]. In another work, Gong et al. prepared a

selective and highly sensitive mercury detection biosensor. This was a DNA-based sensor

fabricated over single-walled carbon nanotubes based on chemiresistive principle. The

device gave a linear range of 100–1,000 nM with LoD as 6.721 nM [48]. García-Aljaro

fabricated a chemiresitive immunosensor for the detection of two pathogens, E. coli and

Bacteriophage T7. Gold electrodes were placed parallelly and bridged with single-walled

carbon nanotubes. In further, antibodies corresponding to these pathogens were im­

mobilized. There was a remarkable increase of resistance observed when the device

was tested with specified E. coli strain. No interference from other strains with LoD of

105 CFU/mL. Whereas, in the case of the virus, LoD of 103 PFU/mL was obtained with no

interference [49]. Liu et al. developed a biosensor device using photolithography and

PDMS. Graphene oxide sheets were coated over a Si/SiO2 substrate. This graphene

oxide was converted to a reduced form via a thermal approach. Rotavirus-specific anti­

bodies were immobilized over this. The sensor was exposed to various rotavirus con­

centration solutions and has an LoD of 102 PFU/mL [50]. Thus, the literature reveals that

printable biosensors have significant importance in environment monitoring and pollutant

detections.

22.3 Conclusion and Future Outlook

In recent times, substantial advances for the fabrication of novel analytical platforms with

flexible and printable biosensor electrodes have taken place. These have been re­

volutionizing tools for the estimation of biological and environmental analytes. With the

integration of automation, microfluidics to prepare biosensors, point-of-care testing has

become feasible. Several advantages, such as instant, selective, and sensitive estimations

at the point of sample collection, multiplexed analyte detection, disposability as well as

re-usable features, ease of use, cost-effectiveness, smaller sample, and reagent volume,

have made them popular. The advances in these types of sensors have made analytical

detections laboratory-free. Various matrices and materials are being explored for fabri­

cation. Since, bioreceptor molecules are sensitive and prone to lose activity, the matrices

play a significant role in the stability of the biosensors. The tremendous growth in the

future, in terms of preparations, materials, and applications is expected. With a special

focus on bridging the gap between academia fabrication, application, and industrial

production, in the future, printable biosensors can be made commercially viable. The

present chapter gives detailed information about the basic working principle of bio­

sensors, types of biosensors based on bioreceptor, generations, and transducers. Brief

information on fabrication is also discussed. Recent advances and some remarkable

works reported for the application of flexible and printable biosensors in the detection of

biomarkers of ailments, pathogens for health monitoring, energy-harvesting fuel cells,

and environmental pollutant detections are also discussed. In conclusion, it can be

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Bioelectronics