Ultrasound-Chargeable Persistent Luminescence Nanoparticles to Generate Self-Propelled Motion and Photothermal/NO Therapy for Synergistic Tumor Treatment

Cancer phototherapy indicates advantages in ease of manipulation,negligible drug resistance, and spatiotemporal control but is confrontedwith challenges in tumor cell accessibility and intermittent lightexcitation. Herein, we propose a strategy with persistent luminescence(PL)-excited photothermal therapy (PTT), concurrent thermophoresis-propelledmotion, and PL-triggered NO release, where PL emission is chargeableby ultrasonication for readily applicable to deep tumors. Mechanoluminescent(ML) nanodots of SrAl2O4:Eu2+ (SAOE)and PL nanodots of ZnGa2O4:Cr3+ (ZGC)were deposited on mesoporous silicates to obtain mSZ nanoparticles(NPs), followed by partially coating with polydopamine (PDA) capsand loading NO donors to prepare Janus mSZ@PDA-NO NPs. The ML emissionbands of SAOE nanodots overlap with the excitation band of ZGC, andthe persistent near-infrared (NIR) emission could be repeatedly activatedby ultrasonication. The PL emission acts as an internal NIR sourceto produce a thermophoretic force and NO gas propellers to drive themotion of Janus NPs. Compared with the commonly used intermittentNIR illumination at both 660 and 808 nm, the persistent motion ofultrasound-activated NPs enhances cellular uptake and long-lastingPTT and intracellular NO levels to combat tumor cells without theuse of any chemotherapeutic drugs. The ultrasound-activated persistentmotion promotes intratumoral accumulation and tumor distribution ofPTT/NO therapeutics and exhibits significantly higher tumor growthinhibition, longer animal survival, and larger intratumoral NO levelsthan those who experience external NIR illumination. Thus, this studydemonstrates a strategy to activate PL emissions and construct PL-excitednanomotors for phototherapy in deep tissues.

Automated summary

This study proposes a strategy that combines persistent luminescence (PL)-excited photothermal therapy (PTT), thermophoresis-propelled motion, and PL-triggered NO release for cancer phototherapy. The strategy allows for readily applicable treatment of deep tumors using ultrasonication. The enhanced cellular uptake, long-lasting PTT, and increased intracellular NO levels achieved through this strategy effectively inhibit tumor growth.