Ultrasensitive and rapid lateral flow biosensor based on exponential rolling circle amplification for the detection...

This study reports a structurally optimized exponential rolling circle amplification (ERCA)-lateral flow assay (LFA) platform that achieves ultrafast and ultrasensitive nucleic acid detection for cancer biomarker diagnosis. By engineering a circular template with multiple strategically positioned Nb.BbvCI cleavage sites and systematically optimizing key reaction parameters, including enzyme concentrations and template design, the amplification time was significantly reduced to under 6 min without compromising sensitivity. Using miR-141, a colorectal cancer biomarker, as a model target, the assay achieved a detection limit of 4 aM and a broad dynamic range from 10 aM to 100 nM. The amplified products hybridize with dual-labeled probes on a lateral flow strip, producing a distinct red test line visible to the naked eye. The entire detection process, from amplification to visual readout, is completed within 10 min under isothermal conditions and without the need for specialized instruments or trained personnel. The platform also demonstrated strong selectivity in human urine spiked with interfering miRNAs. Owing to its modular probe design, this system is readily adaptable to diverse nucleic acid targets, offering a rapid, sensitive, and field-deployable solution for early cancer screening and point-of-care diagnostics.