NIR‐II J‐Aggregated Pt(II)‐Porphyrin‐Based Phosphorescent Probe for Tumor‐Hypoxia Imaging

Abstract The luminescence of traditional phosphorescence‐based hypoxia probes is limited to the visible and first near‐infrared wavelength regions (<1000 nm), which has defects of higher light scattering and lower penetration depth in contrast with the second near‐infrared wavelength window (NIR‐II, 1000–1700 nm) for optical bioimaging. Herein, 5,15‐bis(2,6‐bis(dodecyloxy)phenyl)‐porphyrin platinum(II) (PpyPt) with J‐aggregation induced NIR‐II phosphorescence is reported. J‐aggregates of PpyPt are confirmed by the X‐ray diffraction data in the crystalline state. Moreover, the emission and excitation spectra of PpyPt in the solid states reveal NIR‐II luminescence feature of PpyPt in J‐aggregates. More importantly, by preparation of water‐soluble PpyPt nanoparticles (PpyPt NPs 4.76 ) with J‐aggregates, it has NIR‐II phosphorescent lifetime of microseconds and good oxygen‐sensitivity in water. Moreover, the good biological hypoxia‐sensing potential of PpyPt NPs 4.76 is demonstrated in cells and 4T1‐tumor‐bearing mice. This study provides an efficient strategy to design NIR‐II phosphorescent probe for sensitive tumor‐hypoxia detection through the construction of J‐aggregates.