Degradable and Excretable Ultrasmall Transition Metal Selenide Nanodots for High-Performance Computed Tomography Bioimaging-Guided Photonic Tumor Nanomedicine in NIR-II Biowindow

Transition metal selenide nanodots (NDs) represent distinctive antitumor agents for cancer treatment, but their non-biodegradability may bring serious adverse effects and potential long-term toxicity to internal tissues/organs, which substantially hinder their further clinical translations. In this work, the construction of a multifunctional theranostic nanosystem based on degradable and excretable ultrasmall Rh 3 Se 8 NDs by a general bovine serum albumin-templated strategy is reported. The constructed Rh 3 Se 8 NDs exhibit distinctively high photothermal-conversion efficiency (57.5%) in the second near-infrared biowindow, making them highly applicable for photoacoustic imaging and photonic hyperthermia at the desired wavelength. Rh 3 Se 8 NDs exhibit a high tumor growth inhibition rate (98.1%) on 4T1 breast tumor-bearing mice due to the desirable photonic hyperthermia performances. Especially, the fabricated Rh 3 Se 8 NDs feature the large X-ray attenuation coefficients of the Rh component for contrast-enhanced X-ray computed tomography imaging. Importantly, the prominent biodegradability of Rh 3 Se 8 NDs enables their quick excretion out of the body for potentially avoiding inflammation and mitigating long-term toxicity. Therefore, this work highlights the construction of proof-of-concept biodegradable and excretable ultrasmall inorganic theranostic nanosystems for multiple bioimaging-guided cancer nanotherapeutics, guaranteeing the further clinical translations of inorganic nanoparticles in biomedicine.