SDR-ELISA: Ultrasensitive and high-throughput nucleic acid detection based on antibody-like DNA nanostructure.

An ultrasensitive and high-throughput nucleic acid detection system, termed as strand displacement reaction-enzyme linked immunosorbent assay (SDR-ELISA), has been developed on the basis of antibody-like DNA nanostructures. Three digoxigenin or biotin modified hairpin probes are utilized to construct antibody-like DNA nanostructures that feature affinity toward streptavidin and anti-digoxigenin antibody via isothermal target-triggered SDR amplification. These antibody-like nanostructures have been employed to conjugate horseradish-peroxidase-labeled anti-digoxigenin antibody with streptavidin that is immobilized on microliter plate wells for enzyme-linked colorimetric assay. The resulting SDR-ELISA system is ultrasensitive for target DNA with a low detection limit of 5 fM. Moreover, the SDR-ELISA system is capable of discriminating DNA sequences with single base mutations, and do so in a high-throughput manner by detection and quantification of up to 96 or 384 DNA samples in a single shot. This detection system is further applied to detect other DNA targets such as Shewanella oneidensis specific DNA sequence, which indicates the generality of proposed SDR-ELISA system. The integration of SDR amplification and convenient ELISA technique advances an intelligent strategy for ultrasensitive and high-throughput nucleic acid detection, which may be amenable for direct visual detection and quantification using an accompanying quantitative color chart.