Triphenylamine-equipped 1,8-naphthaolactam: a versatile scaffold for the custom design of efficient subcellular imaging agents.

Fluorescence imaging has enabled much progress in biological fields, while the evolution of commercially available dyes has lagged behind their advanced applications. Herein, we launch triphenylamine-equipped 1,8-naphthaolactam (NP-TPA) as a versatile scaffold for the custom design of an efficient subcellular imaging agent (NP-TPA-Tar), given its bright and constant emissions in various states, significant Stokes shifts, and facile modifiability. The resultant four NP-TPA-Tars maintain excellent emission behavior with targeted modifications and can map the spatial distribution of lysosomes, mitochondria, endoplasmic reticulum, and plasma membrane in Hep G2 cells. Compared to its commercial counterpart, NP-TPA-Tar has a 2.8-25.2 fold increase in Stokes shift, a 1.2-1.9 fold increase in photostability, enhanced targeting capability, and comparable imaging efficiency even at low concentrations of 50 nM. This work will help to accelerate the update of current imaging agents and super-resolution and real-time imaging in biological applications.