27
via FRET between the QD and the dye acceptor (Fig. 2.12) [53]. It should be noted
that the additional background caused by the direct acceptor excitation is virtually
eliminated through the choice of an appropriate excitation wavelength; this led to a
100-fold improvement in sensitivity compared to single organic dye molecular beacon-based detection. This type of sensing schemes can also be amenable to use in a
multiplex format. The narrow and symmetric QD emissions allow easy spectral
deconvolution, and the most straightforward configuration relies on several QD
populations interacting with the same dye acceptor rather than the opposite [53].
2.3.5 Engineered Cell-Based Sensors: The CANARY System
Petrovick et al. have developed a novel inexpensive, genetically engineered whiteblood cell biosensor for the rapid identification of warfare BA pathogens and toxins
[58]. This new sensor was named and abridged as CANARY for “Cellular Analysis
and Notification of Antigen Risks and Yields.” CANARY sensors are capable of
detecting soluble protein toxins, which are an important class of potential bioweapon, and can also be used for sequencing DNA and RNA [58].
A
B
[Model miRNA] (pM)
Fluoresence
lntensity
low high
0
39
78
156
312
625
1250
2500
5000
10000
20000
10 5
10 4
10 3
10 2
10 1
10 2
10 3
10 4
Fig. 2.11 Detection limit and dynamic range of the model miRNA detection microarray. (a)
Image sets of microarrays hybridize with various concentrations of miRNAs from 20 nM to 39 pM
and the background. The 50 μM concentration of oligonucleotide probes printed on slides
pentaplicately. The volume of model miRNA needed to hybridize with microarray was 10 μl. (b)
Correlation between the fluorescence intensity of spots and concentrations of model miRNA. The
values were calculated from the image in (a). The open circle represents the background. (Adapted
from Ref. [53])
2 Detection of Biological Warfare Agents Using Biosensors
via FRET between the QD and the dye acceptor (Fig. 2.12) [53]. It should be noted
that the additional background caused by the direct acceptor excitation is virtually
eliminated through the choice of an appropriate excitation wavelength; this led to a
100-fold improvement in sensitivity compared to single organic dye molecular beacon-based detection. This type of sensing schemes can also be amenable to use in a
multiplex format. The narrow and symmetric QD emissions allow easy spectral
deconvolution, and the most straightforward configuration relies on several QD
populations interacting with the same dye acceptor rather than the opposite [53].
2.3.5 Engineered Cell-Based Sensors: The CANARY System
Petrovick et al. have developed a novel inexpensive, genetically engineered whiteblood cell biosensor for the rapid identification of warfare BA pathogens and toxins
[58]. This new sensor was named and abridged as CANARY for “Cellular Analysis
and Notification of Antigen Risks and Yields.” CANARY sensors are capable of
detecting soluble protein toxins, which are an important class of potential bioweapon, and can also be used for sequencing DNA and RNA [58].
A
B
[Model miRNA] (pM)
Fluoresence
lntensity
low high
0
39
78
156
312
625
1250
2500
5000
10000
20000
10 5
10 4
10 3
10 2
10 1
10 2
10 3
10 4
Fig. 2.11 Detection limit and dynamic range of the model miRNA detection microarray. (a)
Image sets of microarrays hybridize with various concentrations of miRNAs from 20 nM to 39 pM
and the background. The 50 μM concentration of oligonucleotide probes printed on slides
pentaplicately. The volume of model miRNA needed to hybridize with microarray was 10 μl. (b)
Correlation between the fluorescence intensity of spots and concentrations of model miRNA. The
values were calculated from the image in (a). The open circle represents the background. (Adapted
from Ref. [53])
2 Detection of Biological Warfare Agents Using Biosensors