Facile synthesis of noncytotoxic PEGylated dendrimer encapsulated silver sulfide quantum dots for NIR-II biological imaging. Issue 9 (26th February 2020) - Awasthi, Pragati
Abstract : The water-soluble PEG-PATU Ag2 S QDs have been successfully prepared by one-pot method, which display the favorable NIR-II fluorescence property for in vivo bioimaging. Abstract : 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 (Ag2 S 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 Ag2 S 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 Ag2 S QDs in situ . The resulting PEG-PATU Ag2 S 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.