Dual-Mode Ultrasensitive Detection of Nucleic Acids via an Aqueous "seesaw" Strategy by Combining Aggregation-Induced Emission and Plasmonic Colorimetry

Development of simple, robust, and reliable nucleic acid detection strategy holds tremendous promise for cancer or pathogen diagnostics. However, in traditional fluorescent assays, tedious chemical labeling and enzyme-based signal amplification are usually required. Developing label-free, enzyme-free nucleic acid detection strategies is of great significance. In this paper, through combining the hybridization chain reaction (HCR) technique with aggregation-induced emission (AIE)-based fluorometric assay and a gold-nanoparticle-based colorimetric assay, we developed a "seesaw" strategy for label-free, enzyme-free visual detection of nucleic acids. Two sets of signals (solution tonality and fluorescence intensity changes) were generated for one test. The limit of detection of single-strand DNA can be as low as 37.2 fM. The proposed seesaw strategy that integrates fluorometric and colorimetric assay holds great potential for the point-of-care testing of nucleic acids.