Viscosity sensitive fluorescent dyes with excellent photostability based on hemicyanine dyes for targeting cell membrane

• Published in: Sensors and actuators. B, Chemical Chemical, 2021-06, Vol.337, p.129787, Article 129787
• Main Authors: Wang, Ya-Nan, Xu, Bing, Qiu, Li-Hua, Sun, Ru, Xu, Yu-Jie, Ge, Jian-Feng
• Format: Article
• Language: English
• Subjects: Absorption spectra; Benzaldehyde; Bioactivity heterocycle; Biosensors; Cell membrane; Cell membranes; Cyanine dyes; Dyes; Excited-state lifetime; Fluorescent dyes; Optical properties; Toxicity; Viscosity; Viscosity sensitive
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2021.129787

[Display omitted] •Three viscosity-sensitive cell membrane fluorescent dyes (1a-c) were designed and synthesized.•Dyes 1a-c showed remarkable OFF-ON fluorescent response to viscosity at 563 nm, 599 nm and 601 nm, respectively.•Transient absorption spectra exhibited that dye 1b had long excited-state lifetime in 99 % glycerol environment.•Dyes 1a-c with excellent bioactivity could be stably localized on cell membrane of HeLa cells (about 3 h). In this paper, three viscosity sensitive cell membrane fluorescent dyes (1a-c) were obtained. Dyes 1a-c were linked by benzaldehyde (5) and benzoindole (2a), benzoxazole (2b) and benzothiazole (2c), with double bond, respectively. The optical properties showed that dyes 1a-c had larger molar extinction coefficients (3.34 × 104-2.64 × 105 M−1 cm−1) and excellent photostability (89–93 %). In particular, dyes 1a-c had obvious specific response to viscosity. More specifically, they indicated significant OFF-ON fluorescent response at 563 nm, 599 nm and 601 nm to the increase of viscosity (0.89–865 cp), respectively, and displayed an excellent linear relationship with viscosity. Further, the excited-state lifetime of dye 1b was evaluated as long as 828 ps in high viscosity environment by transient absorption spectra. The low cytotoxicity of dyes 1a-c, provided the possibility to be used in living cells. Accordingly, laser confocal experiments clearly exhibited that dyes 1a-c could be well located in the cell membrane. The results can assist in our understanding of the functions of cell membrane as well as application in biosensor and diagnostics.