A design strategy for D-A conjugated polymers for NIR-II fluorescence imaging

The development of bioimaging technology in recent years has shown that second near-infrared (NIR-II) fluorescence imaging (FI) is gradually replacing the traditional visible light and first near-infrared (NIR-I) FI. In the NIR-II window, the light absorption, autofluorescence and scattering of biological tissues are significantly reduced, which strongly promotes the design, development and application of contrast agents with NIR-II emission capabilities. However, the NIR-II bioimaging technology is still incomplete, in the initial stage, and has high research value. In order to increase the quantum yield (QY) of D-A polymers, we used thiophene, 3-methoxythiophene, 3,4-ethylenedioxythiophene (EDOT), 3-hexylthiophene and 3-(2-ethylhexyl)thiophene as strong electron donors and designed and synthesized NIR-II organic polymers P1, P2, P3, P4 and P5, which are of great significance to the molecular design of D-A conjugated polymers. Finally, we explored the FI of the polymers in vivo and in vitro, and verified our idea of increasing the QY.

Automated summary

In recent years, NIR-II fluorescence imaging technology has gradually replaced traditional visible light and NIR-I FI, showing great research value. By utilizing different thiophene derivatives in the design and synthesis of D-A polymers, the quantum yield was successfully increased.