Ultrasensitive graphene quantum dots-based catalytic hairpin assembly amplification resonance light scattering assay for p53 mutant DNA detection

Abstract

In this work, a simple, enzyme-free and ultrasensitive resonance light scattering (RLS) method was developed based on graphene quantum dots (GQDs) with a catalytic hairpin assembly amplification strategy for selective detection of mutant DNA. This method contains two probes, GQDs-H1 and GQDs-H2. Two partially complementary hairpins (H1 and H2) are ingeniously and rationally designed, and they can't spontaneously hybridize with each other in the absence of target. When the target is added, the target binds with GQDs-H1 and forms GQDs-H1: target intermediates. Then, GQDs-H2 hybridizes with the GQDs-H1: target and frees the target, triggering another reaction cycle. A large amount of GQDs-H1:H2-GQDs aggregates are formed, which obviously increase the RLS signals. A limit of detection of 0.8 pmol L−1 and two linear ranges of 1.0 pmol L−1–1.5 nmol L−1 and 1.5–50.0 nmol L−1 for target detection are obtained. This detection method is simple, available, and low-cost. It can be potentially applied to other DNA detection and broadens the sensing application of GQDs for the detection of other significant disease-related markers.