Department of Chemistry, Stanford University, Stanford, California 94305, USA.
State Key Laboratory of Virology, Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China.
Nat Commun. 2017 May 19;8:15269. doi: 10.1038/ncomms15269.
Fluorescence imaging in the second near-infrared window (NIR-II) allows visualization of deep anatomical features with an unprecedented degree of clarity. NIR-II fluorophores draw from a broad spectrum of materials spanning semiconducting nanomaterials to organic molecular dyes, yet unfortunately all water-soluble organic molecules with >1,000 nm emission suffer from low quantum yields that have limited temporal resolution and penetration depth. Here, we report tailoring the supramolecular assemblies of protein complexes with a sulfonated NIR-II organic dye (CH-4T) to produce a brilliant 110-fold increase in fluorescence, resulting in the highest quantum yield molecular fluorophore thus far. The bright molecular complex allowed for the fastest video-rate imaging in the second NIR window with ∼50-fold reduced exposure times at a fast 50 frames-per-second (FPS) capable of resolving mouse cardiac cycles. In addition, we demonstrate that the NIR-II molecular complexes are superior to clinically approved ICG for lymph node imaging deep within the mouse body.
近红外二区（NIR-II）荧光成像是一种新兴的技术，它可以在前所未有的清晰度下对深层的解剖结构进行可视化。NIR-II 荧光团的材料来源非常广泛，包括半导体纳米材料和有机分子染料，但遗憾的是，所有发射波长大于 1000nm 的水溶性有机分子的量子产率都很低，这限制了它们的时间分辨率和穿透深度。在这里，我们报告了通过对蛋白质复合物进行超分子组装，将磺化的 NIR-II 有机染料（CH-4T）与一种磺化的 NIR-II 有机染料（CH-4T）结合，从而产生了高达 110 倍的荧光增强，这是迄今为止量子产率最高的分子荧光团。这种明亮的分子复合物能够以最快的视频帧率（50 帧/秒）在第二近红外窗口中进行成像，从而能够以最快的速度拍摄到老鼠的心脏周期，并且在 50 帧/秒的帧率下，曝光时间也减少了 50 倍。此外，我们还证明了 NIR-II 分子复合物在体内深层淋巴结成像方面优于临床批准的吲哚菁绿（ICG）。
