Intravital Whole‐Process Monitoring Thermo‐Chemotherapy Via 2D Silicon Nanoplatform: A Macro Guidance and Long‐Term Microscopic Precise Imaging Strategy

Tumor angiogenesis is a complex process that is unamenable to intravital whole-process monitoring, especially on microscopic assessment of tumor microvessel and quantifying microvascular hemodynamics before and after the nanotherapeutics, which hinder the understanding of nanotheranostics outcomes in tumor treatment. Herein, a new photoacoustic (PA) imaging-optical coherence tomography angiography (OCTA)-laser speckle (LS) multimodal imaging strategy is first proposed, which is not only able to precisely macro guide the thermo-chemotherapy of tumor by monitoring blood oxygen saturation (SaO2 ) and hemoglobin content (HbT), but also capable of long-term microscopic investigating the microvessel morphology (microvascular density) and hemodynamics changes (relative blood flow) before and after the nanotherapeutics in vivo. Moreover, to realize the tumor thermo-chemotherapy treatment based on this novel multimodal imaging strategy, a 2D 5-fluorouracil silicon nanosheets (5-Fu-Si NSs) therapeutic agent is designed. Furthermore, 2D high-resolution tumor microvascular images in different stage display that tendency of the thermo-chemotherapy effect is closely associated with tumor angiogenesis. Taken together, the investigations establish the fundamental base in theory and technology for further tailoring the novel specific diagnosis and treatment strategy in tumor. More importantly, this technique will be beneficial to evaluate the tumor microvascular response to nanotherapeutics at microscale.