Engineering of a self-feeding and sustainable catalytic hybridization circuit for efficient TK1 mRNA imaging

DNA amplifiers have shown considerable potential in biomarker imaging, yet their practical application is often constrained by slow reaction kinetics and insufficient amplification efficiency. To address these limitations, we herein report a self-feeding and sustainable catalytic hybridization circuit (SCHC) for efficient intracellular mRNA imaging. By integrating rationally designed palindromic sequences into the catalytic hairpin assembly (CHA) reactants, hairpin monomers are induced to form compact hairpin dimers, thereby promoting an increase in local reactant concentration. Benefiting from the self-feeding and sustainable hybridization mechanism, the hairpin dimer reactants undergo alternating assembly to form directionally aligned DNA nanowires upon activation by the initiator (I), concurrently achieving efficient fluorescence transduction. In comparison to the typical CHA system, this strategy exhibits accelerated response kinetics and enhanced amplification performance. Moreover, leveraging its simplified modular design, we further establish a bridge between the analyte and I by introducing a conversion hairpin module, enabling the monitoring and imaging of TK1 mRNA (T) without substantial modifications. We anticipate that this simple yet effective strategy holds tremendous potential for application in human cancer diagnosis.