A photostable AIE luminogen with near infrared emission for monitoring morphological change of plasma membrane

The morphology of plasma membrane is dynamic and keeps changing in order to maintain its homeostasis. Abnormality in cell membrane shape could be viewed as a sign of unhealthy cells. A lipophilic cyanostilbene derivative (AS2CP-TPA) composed of a hydrophilic pyridinium salt and a hydrophobic triphenylamino group was designed for staining the cell membrane and monitoring membrane morphology under different conditions. Due to strong donor-acceptor interaction and aggregation-induced emission property, AS2CP-TPA emits weak emission in aqueous solution, but it lights up the plasma membrance of HeLa cells with near infrared fluorescence under an excitation wavelength of 460 nm. With merits of high photostability and high specificity to plasma membrane, AS2CP-TPA is capable of long-term monitoring of the morphological changes of cell membrane during Hg²⁺ and trypsin treatments.