Relationships between surface tensiometry properties and fluorescence intensity of dark and light exposed monoclonal antibody Nivolumab/Opdivo® by using the contact angle method: A pilot study

Monoclonal antibodies (mAbs) are a class of therapeutic proteins widely used for the treatment of different kinds of cancers and immune-mediated disorders. During their real-life, they encounter various stressors, such as light exposure, able to modify their physicochemical properties both in their formulation and when diluted for patient administration. Several biochemical and biophysical analytical approaches are currently used to characterize the physicochemical properties of mAbs, such as spectroscopic methods (i.e., UV absorption, fluorescence, near and far UV circular dichroism) for conformational studies, size exclusion chromatography, electrophoresis and dynamic light scattering for detecting aggregate formation, LC-MS for their chemical modifications. On these bases, our work is focused on the novel surface tension characterisation of one of these therapeutic mAbs, Nivolumab, in its formulation Opdivo (R) and after dilution and the relationship with classical fluorescence data. In particular, the mAb has been exposed to two different doses of simulated sunlight and the effect of the light stressor has been compared to the mAb kept in the dark. The application of Solid-like methodology, using the Rossi number as main surface tensiometry parameter, allowed us to demonstrate the close relationship between the physical, i.e., surface tension properties, and physico-chemical fluorescence emission of these big molecules.