Design strategies to rhodamine analogue fluorophores for near-infrared II biological imaging applications

Fluorescence imaging enables researchers to visualize a variety of biological tissues and processes with high spatial temporal resolution. Near-infrared II (NIR-II) dyes are more desirable for than near-infrared I (NIR-I) because their reduced light scattering tissue autofluorescence, as well deeper penetration. Whilst the development NIR-II absorption emission fluorophores is challenging, some advances have been made in this area. For example, cyanine derivatives donor-acceptor-donor (D-A-D) structures benzobisthiadiazole core reported common fluorophores. Besides these fluorophores, rhodamine analogues also being realized applications due ability combine sensing. In mini-review, we summarize molecular engineering design strategies, optical properties, developed from analogues. Finally, our outlook future field presented. We believe review will reveal progress made, but challenges developing effective efficient sensing tissues. Consequently, interest biomedical, environmental, other dye related communities.