Long-Term In Vivo Fluorescence Analyses and Imaging-Guided Tumor Surgery in the Second Near-Infrared Window Using a Supramolecular Metallacage

Long-term in vivo fluorescence analysis is growing into a sparkling frontier in gaining deep insights into various biological processes. Exploration of such fluorophores with high performance still remains an appealing yet significantly challenging task. In this study, we have elaborately integrated a second near-infrared (NIR-II) emissive fluorophore with the metal Pt into a self-assembled prism-like metallacage M-DBTP, which enables the intravital long-term tracking of the metal Pt through NIR-II fluorescence imaging technologies. In addition, the intravital bioimaging of the metallacage-loaded nanoparticles (NPs) indicated an extraordinary photographic performance on the mice blood vessels and the rapid clearance of M-DBTP NPs from the blood within 7 h. The subsequent transfer to the bones and the retention of NPs in the bone marrow region for up to 35 days was revealed by long-term fluorescence analysis, which was confirmed by the distribution and metabolism of Pt through an inductively coupled plasma optical emission spectrometer. Moreover, the bright emission of M-DBTP NPs in the NIR-II region enables them to well perform on fluorescence imaging-guided tumor surgery.