Polystyrene Microspheres Coupled with Hybridization Chain Reaction for Dual-Amplified Chemiluminescence Detection of Specific DNA Sequences

We report on a highly sensitive chemiluminescence (CL) assay for the detection of specific DNA sequence, where streptavidin-modified polystyrene microspheres (PS-SA) coupled with hybridization chain reaction (HCR) were employed as dual amplification platform. Briefly, a sandwich-type detection strategy was proposed in our design, which involved capture probe DNA immobilized on the surface of carboxyl-terminated magnetic beads (MB) and the reporter DNA combined with the HCR trigger immobilized on the surface of PS-SA. After that, two hairpin-type monomers were added to initiate the HCR. In the detection system, CL signal was obtained via the instantaneous derivatization reaction between 3,4,5-trimethoxylphenylglyoxal (TMPG) and guanine bases in the target and the HCR complex binding on the magnetic beads. As compared to traditional sandwich type (capture/target/reporter) assays, this dual-amplified strategy for sequence-specific DNA detection showed better specificity, lower detection limit and wider linear response range (linear range of 0.01 fmol-10 pmol and a low detection limit of 5 amol). Moreover, this approach could be easily extended to detect a wide range of specific DNA sequences by modification of the hybridization region. We believe this simple technique will present a significant step towards early diagnoses of diseases.