Simultaneous near-infrared and green fluorescence from single conjugated polymer dots with aggregation-induced emission fluorogen for cell imaging.

Near-infrared fluorescent probes are important and interesting for advanced biological and biomedical applications where the fluorescence technology is employed. Herein, we reported high near-infrared (NIR) fluorescent conjugated polymer dots (Pdots) of two polymers (PTPE-DTNT2 and PTPE-DTNT4) with cross-conjugated aggregation-induced emission fluorogen as the side chain. The photoluminescent quantum yields (PLQYs) of Pdots were up to 31.8% with the near-infrared emission peak of 716 nm, which is among the best values of NIR Pdots reported so far. In addition, Pdots possessed a dual-color emission feature. Thus, dual-color cellular imaging with both Pdots was demonstrated in biological applications; to the best of our knowledge, this is the first reported dual-color cellular imaging with Pdots. The NIR Pdots were also applied in in vivo cytotoxicity analysis and microangiography imaging of zebrafish. We anticipate that NIR Pdots with their dual-color feature will find broad applications in multiplexed biological and biomedical fields.