Urease-DrivenJanus Nanomotors for Dynamic Enrichmentand Multiplexed Detection of Bladder Cancer MicroRNAs in Urine

Bladder cancer diagnosis typically involves approaches such as cystoscopy, biopsy, urine cytology, and medical imaging. However, these invasive procedures carry a risk of complications, and direct in vitro detection on clinical samples often results in low sensitivity. Therefore, this study proposed urease-driven magnetic nanomotors for the simultaneous detection of bladder cancer biomarkers miRNA-21 and miRNA-182 in urine samples, aiming for noninvasive diagnosis. The nanomotor was constructed from gold nanorods, mesoporous organo-silica, Fe₃O₄, and hairpin DNA (hDNA), functioning as a recognition probe for the target miRNAs. In the urea solution, urease catalyzed urea into ammonia and carbon dioxide, propelling the nanomotor for about 60 min, which enhanced the capacity of the probes to capture the target miRNAs. Subsequently, magnetic enrichment enabled highly sensitive dual-miRNA analysis, allowing quantification of miRNA-21 and miRNA-182 with detection limits of 29 and 362 fM, respectively. The nanoprobes also effectively detected miRNAs in spiked urine samples. This simultaneous detection of multiple miRNAs increased the reliability of cancer diagnosis, presenting a novel noninvasive strategy for bladder cancer detection through precise in vitro analysis of actual urine samples.