immobilized the anti-SARS-CoV-2 S1 antibodies in between the source and drain

channel as the sensing materials and recognition element. The anti-SARS-CoV-2

S1 antibodies were immobilized through a non-covalent interaction with the linker

1-pyrenebutanoic acid succinimidyl ester (PBASE). The CNT/FET operated under the

p-type channel depletion principle. When there is binding in between SARS-CoV-2

spike protein and immobilized anti-SARS CoV-2 S1 antibodies, the source-drain current

is depleted. The CNT-FET sensor is able to detect the SARS-CoV-2 infection in a linear

range of 0.1 fg/mL to 5.0 pg/mL and LOD of 4.12 fg/mL. In this work, the large surface

area and high electrical conductivity of SWCNT ensure the high loading capacity of the

anti-SARS-CoV-2 S1 antibodies as the recognition element and enhance the electrical

signal of the sensor.

5.4 Conclusion and Future Look

This chapter discusses metal, metal oxide, and carbon-based nanomaterials’ roles and

applications in sensor platforms for LOC devices. A wide range of LOC device applica­

tions has been developed including immunosensor, environmental, pathogen, protein,

therapeutic, and gas analysis. Well-known nanomaterials properties such as large surface

area and excellent electrical and chemical properties enhance the optical, electrochemical,

and electrical performance of the sensor part in the LOC devices. Most importantly, the

nanomaterials can enhance the sensitivity, allow miniaturization, and provide versatility

to the LOC devices.

FIGURE 5.5

The schematic of SARS-CoV-2 S1 sample testing steps including the CNT-FET biosensor design and compo­

nents. Adapted with permission [ 35] Copyright (2020) The Authors, some rights reserved; exclusive licensee

[Elsevier]. Distributed under a Creative Commons Attribution License 4.0 (CC BY) https://creativecommons.

org/licenses/by/4.0/.

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