Biomedical Engineering Reference
In-Depth Information
assay relies on the observation of greatly enhanced RLS signals that
originate from the aggregation of DNA-Au-NPs, induced by the target
DNA. The reproducibility of this RLS assay is quite good (RSD 2.6%,
n =11).
Figure 8.10 Outline of experimental protocol. cDNA probes generated by
the colabeling of lung RNA with Cy3 and biotin are hybridized
to an array. Following several wash steps to remove unbound
probe, the array is scanned in a luorescence scanner to
capture the Cy3 luorescence image. Treatment of the array
with RLS NPs is accomplished by incubating the slides
with anti-biotin antibody-coated 80 nm diameter Au NPs.
The same array is then imaged in a CCD-based white light
imaging system to generate the RLS image. Reprinted from
Ref. 57 with permission.
In addition to DNA-Au-NPs, bare (non-bioconjugated) Au NPs
also make useful RLS probes for the detection of DNA, based on non-
cross-linking reactions. Recognition of a quadruplex DNA structure
using unmodiied Au NPs is realized using a simple, label-free,
RLS approach, based on charge variations before and after DNA
folding. 59
The adsorption of uncoiled DNA on the surface of Au NPs
prevents the NPs from aggregation in highly concentrated ionic
media. Potassium ions induce the telomere DNA to change its
conformation from an uncoiled to a quadruplex structure via
intermolecular hydrogen bonding, leading to aggregation of the Au
NPs and thus, increased RLS signals. A single point energy calculation
shows that, when compared to the unfolded DNA, the quadruplex
 
Search WWH ::




Custom Search