(56b) Synthesis of Novel Fluorescent Surfactants and Their Interaction with Living Cells

Surfactants are widely applied in products which are directly in contact with human body such as cosmetics, detergents and clothing. Therefore, the health problems posed by exposure to surfactants are of great concern. Understanding the interactions of surfactants with living cells would be helpful to assess and control their safety on human exposure.

The present study aimed to investigate the dynamic interactions of surfactants with living cells by a visualized method. A series of trisodium 8-hydroxypyrene-1,3,6-trisulfonate (HPTS) based anionic fluorescent surfactants with various hydrophobic carbon chain were synthesized and characterized in structure, fluorescent properties and surface activity properties. Their excitation and emission maxima were all at 405 nm and 440 nm, respectively. The longer the carbon chain, the weaker the fluorescence intensity. Meanwhile, as anionic surfactants, they could lower the surface tension of PBS solution to a minimum of 49.03mN/m. Longer carbon chain yielded better surface activity. MTT assay showed that the cytotoxicity increased with the length of hydrophobic chain. Dynamic process of surfactants entering cells and causing cell apoptosis were observed using a fluorescence microscope.

The synthesized fluorescent surfactants had both fluorescence and surface activity, thus could act as visible model anionic molecules to explore the interaction of surfactants with life.