Probing how alkyl ethoxylate nonionic surfactants become embedded in human corneal cell membrane

Nonionic surfactants are widely used as adjuvants in pesticide formulation and agro-sprays. During spraying, they may come into direct contact with human eyes, causing corneal irritation. Our recent studies have shown that nonionic surfactants kill cells by disrupting the cytoplasmic membrane at or above its critical micellar concentration, leading to cytoplasmic leakage. In this work, we propose to use neutron reflection to study how nonionic CnEm interacts with supported lipid bilayer under a set of H/D contrasts involving deuterated lipid, surfactants and H2O and D2O. We will focus on examining the structural features of cytotoxicity of two sets of nonionic surfactants (alkyl ethoxylate, CnEm) towards the lipid membrane bilayer, with one set composed of varied surfactant head length but fixed tail length (C12E4-23) and the other set oppositely composed (C10-16E6). These structural features will enable us to understand how different nonionic surfactants impose different membrane-lytic interactions and therefore make useful correlation to cytotoxicity data.