Stabilizing Organic Radical Anion in Water by Metal–Organic Frameworks with Enhanced Stability for NIR Photothermal Antibacterial Therapy

Tremendous efforts have been made in the development of highly stable organic radicals, especially in water and at high temperatures. The development, as yet, is mainly restricted to the lack of a useful way. Here we report a water-dispersible metal–organic framework-stabilized organic radical anion with superior stability. By shielding in zeolitic imidazolate framework-8 (ZIF-8), the water-dispersed radical nanoparticles (ZIF-Radical NPs) achieve a 1770-fold improvement in radical stability compared with free TCNQ radical species in water. Moreover, ZIF-Radical NPs show good tolerance for harsh conditions. Upon 808 nm light irradiation, the ZIF-Radical NPs exhibit good photothermal conversion performances with a high stability. Nearly 100% killing efficiency toward both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus was also achieved by efficient photothermal antibacterial activity of ZIF-Radical NPs. This work offers a new way for the development of a stable radical material for near-infrared biomedical applications.