One-Step Homogeneous DNA Assay with Single-Nanoparticle Detection

摘要

We have demonstrated a novel method to detect special sequence DNA targets in one-step homogeneous hybridization solutions with single-NP detection. The DNA targets can be detected at 1 pm by using AuNP probes, which increase the sensitivity by three orders of magnitude over that of colorimetric methods, without any signal amplification process. Compared with other techniques for the detection of AuNPs in homogeneous solutions, such as dynamic light scattering and single AuNP counter techniques, ICP-MS can simultaneously differentiate AuNPs of different sizes and provide accurate quantification of AuNPs, and this advantage makes the measurement more reliable and accurate. Additionally, ICP-MS is able to detect NPs without any special requirements for optical and electrochemical properties, so an expanding range of NPs such as biological tags can be applied. Moreover, by choosing a time-of-flight or multi-collector analyzer, encoded NPs composed of different elements can be simultaneously analyzed. Therefore, the proposed method may be extended to massively parallel and high-throughput analysis of DNA and other biological molecules.