A one-step highly sensitive method for DNA detection using dynamic light scattering.
A one-step homogeneous DNA detection method with high sensitivity was developed using gold nanoparticles (AuNPs) coupled with dynamic light scattering (DLS) measurement. Citrate-protected AuNPs with a diameter of 30 nm were first functionalized with two sets of single-stranded DNA probes and then used as optical probes for DNA detection. In the presence of target DNA, the hybridization between target DNA and the two nanoparticle probes caused the formation of nanoparticle dimers, trimers, and oligomers. As a result, the nanoparticle aggregation increased the average diameter of the whole nanoparticle population, which can be monitored simply by DLS measurement. A quantitative correlation can be established between the average diameter of the nanoparticles and the target DNA concentration. This DLS-based assay is extremely easy to conduct and requires no additional separation and amplification steps. The detection limit is around 1 pM, which is 4 orders of magnitude better than that of light-absorption-based methods. Single base pair mismatched DNAs can be readily discriminated from perfectly matched target DNAs using this assay.
Dai
Qiu
Q
NanoScience Technology Center, Department of Chemistry, University of Central Florida, 12424 Research Parkway Suite 400, Orlando, Florida 32826, USA.
Liu
Xiong
X
Coutts
Janelle
J
Austin
Lauren
L
Huo
Qun
Q
D004247:DNA / Q000032:analysis*; D006046:Gold; D008027:Light; D053768:Metal Nanoparticles; D008722:Methods; D015336:Molecular Probe Techniques; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D012542:Scattering, Radiation
D015345:Oligonucleotide Probes; D006046:Gold; D004247:DNA