| Abstract: | Viruses and other bioagents are of high medical and biodefense concern
and their detection at concentrations well below the threshold necessary
to cause health hazards continues to be a challenge with respect to
sensitivity, specificity, and selectivity. Ideally, assays for accurate
and real time detection of viral agents and other bioagents would not
necessitate any pre-processing of the analyte, which would make them
applicable for example to bodily fluids (blood, sputum) and man-made as
well as naturally occurring bodies of water (pools, rivers). We describe
herein a robust biosensor that combines the sensitivity of surface
acoustic waves (SAW) generated at a frequency of 325 MHz with the
specificity provided by antibodies and other ligands for the detection of
viral agents. In preferred embodiments, a lithium tantalate based SAW
transducer with silicon dioxide waveguide sensor platform featuring three
test and one reference delay lines was used to adsorb antibodies directed
against Coxsackie virus B4 or the negative-stranded category A bioagent
Sin Nombre virus (SNV), a member of the genus Hantavirus, family
Bunyaviridae, negative-stranded RNA viruses. Rapid detection (within
seconds) of increasing concentrations of viral particles was linear over
a range of order of magnitude for both viruses, although the sensor was
approximately 50.times.10.sup.4-fold more sensitive for the detection of
SNV. For both pathogens, the sensor's selectivity for its target was not
compromised by the presence of confounding Herpes Simplex virus type 1.
The biosensor was able to detect SNV at doses lower than the load of
virus typically found in a human patient suffering from hantavirus
cardiopulmonary syndrome (HCPS). Further, in a proof-of-principle real
world application, the SAW biosensor was capable of selectively detecting
SNV agents in complex solutions, such as naturally occurring bodies of
water (river, sewage effluent) without analyte pre-processing. |