DNA nanotechnology and catalytic hairpin assembly cascade: A novel approach in achieving sensitive detection and in situ imaging of phosphatidylserine on living cell membranes

Phosphatidylserine (PS) is a vital lipid in eukaryotic cell membranes, and its content variations are closely associated with various diseases. Therefore, tracking PS in living cells is invaluable. Here, we designed an aptamer-initiated cascade catalytic hairpin assembly (CHA)-based DNA triangular prism (AI-CDTP) for sensitive detection and in situ imaging of PS on living cell membranes. The aptamer-initiated DNA triangular prism (AI-DTP) was prepared as precursor probe using several single-stranded DNA through a simple one-pot annealing process, which takes only a few minutes. Additionally, the sensitivity of the PS-triggered CHA circuit was enhanced by coupling the hairpin probes on AI-DTP. This coupling increased the local concentration and accelerated the reaction kinetics, achieving a detection limit as low as 1.39 nM. Compared with the traditional plasmid systems, AI-CDTP simplifies the preparation process, responds rapidly, and demonstrates excellent self-delivery, biocompatibility and stability. Thus, our developed strategy provides a reliable platform for the sensitive imaging of intracellular PS.