Integrated Near-Infrared Light-Driven Janus Micromotor-Fluorescent Nanodiamond Dynamic Sensing Platform for Active Motion-Enhanced Biodetection

Efficient and rapid quantitative detection of microRNAs and proteins is critical for early cancer diagnosis. However, conventional fluorescence assays often suffer from photobleaching, autofluorescence interference, and slow mass transport, which result in unstable signals during static incubation. Herein, we report a near-infrared (NIR)-driven dynamic biosensing platform (JMMs-FNDs) that integrates highly photostable fluorescent nanodiamonds (FNDs) as signal reporters with self-propelled H-MnO₂-Au JMMs, enabling dynamic capture and efficient enrichment of target molecules and probes. The H-MnO₂-Au JMMs consist of a mesoporous hollow MnO₂ shell with asymmetrically deposited gold nanoparticles. Under NIR irradiation, an asymmetric photothermal effect induces thermophoretic propulsion, which significantly enhances mass transport. Meanwhile, the mesoporous shell further promotes target-receptor interactions. As a result, the capture efficiency for miRNA-21 increased from 52.48% to 78.46%, enabling ultrasensitive detection with a detection limit of 0.72 fM, approximately 40-fold lower than that obtained under conventional static incubation. Moreover, by incorporating a strand-displacement recognition strategy, quantitative detection of MUC1 was further demonstrated. By integrating self-propulsion with stable fluorescence signaling, the JMMs-FNDs sensing platform enabling efficient and highly sensitive fluorescence biodetection.