ac5011316_si_001.pdf (606.46 kB)
Assembly of Multiple DNA Components through Target Binding toward Homogeneous, Isothermally Amplified, and Specific Detection of Proteins
journal contribution
posted on 2014-07-15, 00:00 authored by Bin Deng, Junbo Chen, Hongquan ZhangWe describe a strategy of utilizing
specific target binding to
trigger assembly of three DNA components that are otherwise unable
to spontaneously assemble with one another. This binding-induced DNA
assembly forms a three-arm DNA junction, subsequently initiating nicking
endonuclease-assisted isothermal fluorescence signal amplification.
Real-time monitoring of fluorescence enables amplified detection of
specific protein targets. The implementation of the strategy necessitates
the simultaneous binding of a single target molecule with two affinity
ligands each conjugated to a DNA motif. Simple alternation of affinity
ligands enables different protein targets to induce the formation
of the DNA junction and subsequent isothermal amplification. The use
of the strategy allowed us to develop a sensitive assay for proteins
with three appealing features: homogeneous analysis without the need
for separation, isothermal amplification, and high specificity. Streptavidin
was chosen as an initial target to establish and optimize the assay.
Sensitivity of protein detection was improved by 1000-fold upon the
application of isothermal amplification. A limit of detection of 10
pM was achieved for detection of prostate-specific antigen in buffer
and diluted serum. The combination of its three appealing features
makes the assay attractive for potential applications in molecular
diagnosis, point-of-care testing, and on-site analysis.