Biomedical Engineering Reference
In-Depth Information
The results of the hybridization in biochannel devices with single-stranded
amplicon are shown in Fig. 7.3, which presents the fluorescent scanner image
of two adjacent channels that have been hybridized with samples obtained
by PCR amplification of
E. coli
and
E. faecalis
samples. Probes for each of
the pathogenic bacteria surrogate strains were printed in duplicate, with all
channels being treated identically. The mainly single-stranded amplification
product of the PCR was hybridized directly to the channel network, without
the addition of hybridization buffer. The salinity was only one-tenth of con-
ventional hybridization solutions, which have a salinity of at least 0.5 M. Al-
though slow hybridization would be expected under these low-salt conditions,
the salinity was su
cient to produce intense, specific hybridization signals in
only 30 minutes.
Fig. 7.3.
Fluorescent scanner image of two biochannel device channels after hy-
bridization. The left channel has been hybridized to amplicon obtained with a PCR
from
E. faecalis
, the right channel with
E. coli
amplicon
7.2.2 Biochannel Devices for Electrochemical Detection -
Reaction Kinetics Studies
In order to evaluate the kinetics of hybridization in the biochannel devices,
we chose to use electrochemistry-based single-nucleotide polymorphism (SNP)
detection arrays (eSensor
TM
) from Motorola Life Sciences [24]. The use of a
homogenous assay allowed for continuous measurement of DNA hybridization.
