3.4 Sensors
Sensors are used in a wide range of areas including environmental and
disease monitoring to detect and quantify selected analytes from complex
dirty solutions. Effective sensors must have high selectivity,
sensitivity, and structural stability over the range of environmental
conditions they are likely to experience. Selectivity for a specific
analyte in mixed samples is achieved by functionalizing the viral
surface with metals, enzymes and/or other chemicals. For example,
palladium-coated TMV rapidly and reversibly detects hydrogen at room
temperatures [47]. Similarly, gold coated nanowires conjugated with
folic acid via coupling agents can interact with the folate receptors on
tumor cells to detect cancers with high sensitivity [19].
Additionally, TMV may be decorated with biotin to enable binding of
enzymes to detect penicillin [61]. Other desirable sensor properties
such as sensitivity and stability arise from the nature of viral
biotemplates themselves. TMV’s high surface area to volume ratio allows
for more contact with analytes, amplifying signal generation and
improving device sensitivity [62]. Similarly, TMV structure is very
stable in high temperatures and over a wide range of pHs (Table 1) that
may be encountered in the analysis of complex mixtures, making
biosensors derived from TMV more durable and rugged.