Au nanoparticles fluorescence switch-mediated target recycling amplification strategy for sensitive nucleic acid detection

Abstract

The sensitive detection of clinically significant DNA is of critical importance in early clinical diagnostics and medical research. Herein, we developed a sensitive fluorescent method for the detection of DNA fragments from the breast cancer 1 gene based on Au nanoparticles (AuNPs) fluorescence switch-mediated target recycling amplification. First, the designed FAM-labeled single-stranded DNA recognition probes at the 5′-terminus (donated as F-DNA) were adsorbed on the surface of AuNPs, followed by the substantial fluorescence quenching of the FAM. Then, the F-DNA specifically hybridized with the complementary region of the target DNA (T-DNA) and desorbed from the AuNPs surface, leading to the recovery of the partially quenched fluorescence. Finally, under the action of Exo III, T-DNA was released and hybridized with F-DNA for the target recycling; thereby large amounts of fluorescent probe fragments were obtained, resulting in significant fluorescent amplification for T-DNA detection. The proposed strategy exhibited a detection limit of 1.0 × 10⁻¹¹ mol L⁻¹ and good selectivity towards the mismatched T-DNA, which was better than or comparable to the existing nanomaterial-based fluorescent methods. The method possessed perfect recoveries in the human serum and cell lysate. Therefore, the proposed strategy would offer a new potential for quantification of specific DNA sequences in early clinical diagnostics and medical research.