Acid responsiveness of emissive morpholinyl aminoquinolines and their use for cell fluorescence imaging

Herein, we report emissive aminoquinoline derivatives (TFMAQ) containing alkylmorpholine and arylmorpholine groups and their photophysical properties, acid-responsiveness, and organelle targeting. The alkylmorpholine group is well-known to favour accumulation in lysosomes and be acid-responsive, but, counterintuitively, the TFMAQ derivatives containing ethylmorpholine groups showed limited accumulation in lysosomes and, instead, preferential accumulation in lipid droplets. The findings reported here will aid the development of organelle/tissue specific dyes for cell imaging and diagnosis.

Automated summary

In this study, emissive aminoquinoline derivatives (TFMAQ) containing alkylmorpholine and arylmorpholine groups were investigated for their photophysical properties, acid-responsiveness, and organelle targeting. Surprisingly, the TFMAQ derivatives with ethylmorpholine groups showed limited accumulation in lysosomes, which are known to favor alkylmorpholine group accumulation, and instead preferred accumulation in lipid droplets. These findings have significant implications for the development of organelle/tissue specific dyes for cell imaging and diagnosis.