Gold nanorods-based lateral flow biosensors for sensitive detection of nucleic acids.

A gold nanorod (AuNR)-based lateral flow nucleic acid biosensor (LFNAB) is reported for visual detection of DNA with a short test time and high sensitivity. AuNRs with an approximate length of 60 nm were utilized as a colored tag to label the detection DNA probe (Det-DNA). The capture DNA probe (Cap-DNA) was immobilized on the test region of LFNAB. Sandwich-type complex was formed among the AuNR-Det-DNA, target DNA (Tar-DNA), and Cap-DNA on the LFNAB by Watson-Crick base pairing. In the presence of Tar-DNA, AuNRs were thus seized on the test region of LFNAB, and the accumulation of AuNRs subsequently produced a characteristic colored band. The optimized LFNAB was able to detect 10 pM Tar-DNA without instrumentation. Quantitative analysis could be established by measuring the intensity of test band using a portable strip reader, and the detection limit of 2 pM target DNA was achieved on the LFNAB without signal amplification. The detection limit of the AuNR-based LFNAB is 250-fold lower than that of gold nanoparticle (AuNP)-based LFNABs. This work unveiled a sensitive, rapid, and economical strategy for the detection of nucleic acids, and simultaneously opening new promising routes for disease diagnosis and clinical applications. Gold nanorods are used as colored tags for lateral flow nucleic acid biosensor.