RESUMEN
A label-free and enzyme-free fluorescent DNA sensor based on hybridization chain reaction ( HCR) and vacant site-binding molecule was developed. By rationally incorporating a cytosine in hairpin DNAs for HCR and utilizing vacant site-binding fluorophore ATMND, sensitive DNA detection was achieved, resulting from the large amount of vacant sites presented on the long DNA nanostructures upon HCR. Gel electrophoresis and atomic force microscopy were performed to characterize the hybridization chain reaction. Under the optimized conditions, the method could sensitively detect the target DNA with the low detection limit of 2. 0 nmol/L. The method shows great potential in signal amplification for DNA detection with advantages such as simple, label-free and low-cost.