Protecting monoclonal antibodies via competitive interfacial adsorption of nonionic surfactants

Bioengineered monoclonal antibodies (mAbs) have gained significant recognition as medical therapies. However, during processing, storage and use, mAbs are susceptible to interfacial adsorption and desorption, leading to structural deformation and aggregation, and undermining their bioactivity. To suppress antibody surface adsorption, nonionic surfactants are commonly used in formulation. But how surface hydrophobicity affects the adsorption and desorption of mAbs and nonionic surfactants individually and as a mixture remains inconclusive.

The rapid tuning of the siliconized surface from hydrophobic to hydrophilic was controlled by the UV oxidation time of a self-assembled trimethoxy(7-octen-1-yl)silane (TMOS) monolayer. Spectroscopic ellipsometry and neutron reflection were used to determine the dynamic adsorption and structural changes of the co-adsorbed mAb (COE-3) and the commercial nonionic surfactant PS80, which is composed primarily of polyoxyethylene-sorbitan monooleate with an average molecular weight of about 1310 g/mol.

COE-3 adsorption on both TMOS or UV-TMOS surface was irreversible. However, nonionic surfactant PS80 could partially remove pre-adsorbed COE-3 from these surfaces, forming a co-adsorption layer. Interestingly, while the hydrophobic TMOS surface prevented mAb adsorption when pre-treated with PS80, the amphiphilic UV-TMOS did not. Furthermore, when COE-3 and PS80 were injected as a mixture, PS80 formed a preventative layer on both surfaces against COE-3 adsorption. These results highlight the significance of surface hydrophobicity in controlling mAb adsorption in the presence of nonionic surfactants.