Beyond Phototherapy: Recent Advances in Multifunctional Fluorescent Nanoparticles for Light-Triggered Tumor Theranostics

Nanoparticles (NPs) have attracted great attention for cancer diagnosis and therapy thanks to their unique properties that enable specific tumor uptake, image-guided diagnosis, and tumor suppression triggered by one or more therapeutic modalities. Light-activated NPs have gained particular interest as minimally invasive theranostic agents for fluorescence-guided tumor diagnosis and highly selective phototherapy. The most recent advances in the field focus on shifting their spectral operation range to the second biological window (1000-1400 nm), while improving their efficacy, selectivity, and multifunctionality. In the past few years, multiple systems capable of light-triggered tumor diagnosis through fluorescence imaging (and in many cases, other imaging modalities) and subsequent tumor therapy have been synthesized and evaluated in small animal models. This review summarizes the different approaches for in vivo tumor theranostics, highlighting their advantages and limitations, and provides a critical analysis of the current state of the field.