Biosensors for the Detection of Waterborne Pathogens - Waterborne Pathogens: Detection Methods and Applications - page 206

Second, in 2009, the sensor surface was functionalized with mannose, and
concanavalin A was employed to mediate the bacteria mannose reaction. 64
This latter system reported detection of as little as 60cellsmL −1 with a
sample volume of 2.5 mL, incubated for 2.5 h.
Finally, a microcantilever (µC) system operated in bending mode was
capable of detection of 10 6 cfu mL −1 within 2 h. 65
7.5.2. Salmonella
For this bacterium, all three transduction methods have been trialed. How-
ever, to the best of our knowledge, there is no review paper summarizing
these developments. In terms of optical sensors, FRET-based optical fibers
yielded an LOD of 10 4 cfu mL −1 within 5 min. 66 An optical grating coupler,
where the use of 3-aminopropyltriethoxysilane was found to be an optimal
surface immobilization strategy for the capture antibody, had an identical
LOD 67 as did a LFA. 68 In this LFA, liposomes were employed for signal
amplification improving on previous work by several orders of magnitude.
Oh et al. reported an LOD for a SAM protein G-based SPR immunosen-
sor in 2004 of 10 2 cfu mL −1 . 69 Waswa et al. improved this technique in 2006
with a protein A immobilized immunosensor that achieved 23 cfu mL −1 . 62
As for E. coli , amperometric biosensors were developed in the 1990s 45
whereas the use of electrochemical impedance spectroscopy (EIS) is more
recent. Novel statistical signal processing was combined with impedance
Figure 7.16 Real-time response of the magnetoelastic E. coli O157:H7 sensor resonance
frequency to E. coli O157:H7 concentration, 0-10 6 cells mL −1 , in pH 10.0 PBS containing
BCIP. Source: Figure 6 from Ref. 42 . Reprinted with permission. Copyright (2003) American
Chemical Society.