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Updated: Feb 18, 2026
DNA-magnetic Particle Binding Analysis by Dynamic and Electrophoretic Light Scattering
Published on: November 9, 2017
Scattering measurement of single particle for highly sensitive homogeneous detection of DNA in serum
Liang Zhu1, Guohua Li1, Yonghong He1
1Institute of Optical Imaging and Sensing, Shenzhen Key Laboratory for Minimal Invasive Medical Technologies, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, People's Republic of China; Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China.
Abstract:
A highly sensitive homogeneous method for DNA detection has been developed. The system relies on two kinds of gold nanorod (AuNR) probes with complementary DNA sequences to the target DNA. In the presence of the target DNA, two kinds of AuNR probes are assembling into dimers or small aggregates. The target-induced AuNR aggregate has higher scattering intensity than that of a single AuNR because of the plasmonic coupling effect. Dark field microscopy was utilized to image the single particle and measure its scattering intensity. We wrote our own Matlab code and used it to extract the scattering signal of all particles. Difference in distribution of scattering intensity between the single AuNR and its aggregate provides a quantitative basis for the detection of target DNA. A linear dynamic range spanning from 0.1pM to 1nM and a detection limit of ~ 30fM were achieved for the detection of DNA in serum sample.
