Plasmon-Enhanced Magnetic Fluorescent Nanoprobe for Ultrasensitive Detection of Urinary miRNA-96 Enabling Early Diagnosis and Risk Stratification of Bladder Cancer.

Bladder cancer (BC) represents a major threat to urinary tract health, and its early detection is critically associated with improved patient survival and clinical outcomes. Conventional diagnostic approaches, including white-light cystoscopy and urinary cytology, are limited by invasiveness, suboptimal sensitivity (30-50% for low-grade tumors), or insufficient specificity, highlighting an unmet clinical need for noninvasive, ultrasensitive, and quantitative tools for BC biomarker detection. Herein, we develop a plasmon-enhanced magnetic-fluorescent nanoplatform, rationally designed by integrating Fe3O4@Au magnetic nanoparticles (MNPs) with lanthanide-doped upconversion nanoparticles (UCNPs), enabling ultrasensitive quantification of urinary miRNA-96, a well-established oncogenic biomarker that is overexpressed in BC tissues and excreted in urine. Importantly, the Fe3O4@Au MNPs serve a dual functional role: (i) facilitating rapid and efficient magnetic isolation of target-bound UCNPs from human urine, thereby reducing matrix-derived background interference, and (ii) acting as localized plasmonic nanoantennas that enhance UCNPs upconversion luminescence through near-field electromagnetic coupling. By leveraging this synergistic design, the nanoplatform exhibits an exceptionally broad linear dynamic range (2.5-500 aM), an ultralow detection limit of 0.8 aM, and outstanding molecular selectivity. Clinical validation using deidentified, prospectively collected urine specimens from patients and healthy donors demonstrates that the assay accurately stratifies clinical status. In summary, this work introduces a clinically translatable nanoplatform that uniquely integrates plasmonic signal amplification, magnetic purification of native biofluids, and direct urinary miRNA analysis, thereby establishing a paradigm for noninvasive, early stage BC diagnosis and providing a versatile framework for next-generation miRNA-based cancer diagnostics.