Bioinspired DNA sponge interface coupled with deoxyribozyme autography for nanoparticle-free nucleic acid detection on a strip.

Conventional nanoparticle-labeled lateral flow assays often face limitations such as aggregation in incompatible buffers, complex preparation procedures, and high costs. Here, we present a nanolabel-free lateral flow chromatographic platform that integrates lossless strand displacement amplification of deoxyribozyme with a barcoded DNA sponge-based capture interface. In this design, functional G-quadruplex structures serve as intrinsic reporting units instead of conventional nanoparticles, generating catalytic or fluorescent signals upon ligand binding. The DNA sponge network functions as a high-capacity capture interface on the test line. Its porous and hydrophilic architecture enhances probe loading and locally retains the flowing solution, thereby prolonging the interaction between amplification products and immobilized multivalent probes. This structural confinement improves the capture efficiency of nucleic acid amplicons and effectively suppresses the coffee-ring effect during the fabrication of the capture interface, ensuring high probe density within a small sensing zone, uniform probe distribution, and reproducible signal readout. For microRNA detection, the proposed platform achieves a detection limit as low as 10 fM and demonstrates the capability for single-base mismatch discrimination. This work presents an interface-engineering strategy that enables label-free signal generation and robust probe immobilization, broadening the integration of nucleic acid amplification with strip-based biosensing for advanced biomedical analysis.