Inorganic cancer phototheranostics in second biowindow

Cancer phototheranostics in second biological window (1000–1500 nm) has recently emerged as a promising alternative of first biological window because of high light penetration depth, minimal tissue absorption, reduced scattering, better resolution, less autofluorescence, and high signal to noise ratio. With the rapid progress in chemical biology, nanomedicine, and material science, multifunctional inorganic phototheranostics with broadband absorption (1000–1350 nm) in near-infrared-II (NIR-II) biowindow has been actively developed to diagnose and treat deeply localized tumors simultaneously. Hence, this Perspective focuses on the latest developments in NIR-II inorganic cancer phototheranostics. A systematic comparison of NIR-I vs NIR-II biowindow has been made, followed by the technical guidelines regarding the design considerations of theranostics. The general fabrication strategies of NIR-II activated theranostics are also briefly introduced. A comprehensive discussion about the potential multimodal cancer theranostic applications of inorganic nanosystems in NIR-II biowindow has been provided, whereas the potential obstacles in clinical translation and future prospects are also highlighted in Sec. V. This Perspective will reveal the essence of NIR-II photo-induced cancer theranostics, which may push forward the development of next-generation personalized cancer photo-nanomedicines.