Recent advances in NIR-II fluorescence imaging-guided type-I photodynamic therapy

Abstract

Phototheranostics, which integrates tissue imaging with phototherapy, has shown considerable promise in the early diagnosis and precision treatment of cancers. However, conventional phototheranostic materials are often constrained by the hypoxic tumor microenvironment and limited tissue penetration, resulting in suboptimal performance for deep-seated tumors. Recently, long-wavelength-activated type-I photodynamic therapy (PDT) systems coupled with near-infrared-II (NIR-II) fluorescence have attracted attention due to their improved tissue penetration, high detection sensitivity, and less oxygen-dependent reactive oxygen species generation, positioning them as an ideal platform for treating deep-seated tumors. In this review, we summarize cutting-edge advances in NIR-II fluorescence imaging (FLI)-guided PDT materials, with an emphasis on molecular design strategies and corresponding phototheranostic performance. We also provide in-depth analysis of effective design principles and highlight key breakthroughs in the field. Finally, we discuss current challenges and future prospects for NIR-II emissive photosensitizers, with the goal of advancing the development of NIR-II FLI-guided PDT.