How does hydrophilicity change affect adsorption of non-ionic surfactant and monoclonal antibody on PDMS surface?

Coating of a layer of polydimethylsiloxane (PDMS) film on the surface of glass or polymeric syringes is widely adopted as the common approach to reduce interfacial friction and avoid syringe jamming. However, the PDMS surface has very different chemical nature from glass or solid plastic substrate and will elicit adsorption of antibody therapeutics, causing structural instability and aggregation. Nonionic surfactants such as Tween 80 (PS80) are widely used to control antibody adsorption, but their exact impact is little explored because many techniques cannot distinguish protein from surfactant at the interface. Following our recent studies of adsorption of PS80 surfactants and antibody onto the PDMS film coated silicon substrate by spectroscopic ellipsometry, we propose a set of neutron reflection studies to determine interfacial structural features that underline how PS80 with different numbers of EO unit can co-adsorb with COE-3 at the PDMS/solution interface.