Center for Bionanoengineering and Key Laboratory of Biomass Chemical Engineering of Ministry of Education, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, China 310027.
CAS Key Laboratory of Nano-Bio Interface, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, P.R. China 215123.
Nanoscale. 2020 Mar 5;12(9):5678-5684. doi: 10.1039/c9nr10918h.
Near-infrared-II (NIR-II, 1000-1700 nm) bioimaging features high penetration depth and high spatio-temporal resolution compared to traditional fluorescence imaging, but the key is to develop stable and biocompatible NIR-II fluorophores suitable for in vivo applications. Silver sulfide quantum dots (Ag2S QDs) have been demonstrated to be excellent for in vivo NIR-II imaging with unique optical properties and decent biocompatibility, but they often require complex post modifications for in vivo applications. Herein we demonstrate a facile one-pot strategy to synthesize PEGylated dendrimer-encapsulated Ag2S QDs useful for in vivo NIR-II imaging. Silver ions were first loaded into the core of an acylthiourea-functionalized dendrimer (PEG-PATU) through coordination between silver ions and acylthiourea groups, followed by the addition of sodium sulfide to form Ag2S QDs in situ. The resulting PEG-PATU Ag2S QDs exhibit excellent NIR-II fluorescence signals, and thus could be used for high efficiency labelling and tracking of A549 cancer cell mobility in vivo and real time visualization of the vast circulatory network of a mouse.
近红外二区（NIR-II，1000-1700nm）生物成像与传统荧光成像相比具有更高的穿透深度和更高的时空分辨率，但关键是要开发出适合体内应用的稳定且具有生物相容性的近红外二区荧光团。硫化银量子点（Ag2S QDs）具有独特的光学性质和良好的生物相容性，已被证明非常适合体内近红外二区成像，但它们通常需要进行复杂的后期修饰才能用于体内应用。在此，我们展示了一种简便的一锅法策略，用于合成用于体内近红外二区成像的 PEG 化树枝状大分子包裹的 Ag2S QDs。银离子首先通过银离子与硫代酰胺基团之间的配位作用被负载到酰基硫脲功能化树枝状大分子（PEG-PATU）的核中，然后加入硫化钠原位形成 Ag2S QDs。所得的 PEG-PATU Ag2S QDs 表现出优异的近红外二区荧光信号，因此可用于高效标记和跟踪 A549 癌细胞在体内的迁移，并实时可视化小鼠的庞大循环网络。
