Paper Number
IR4 

Session
Interfacial Rheology

Title
mAb-surfactant stability and rheology at the air-water interface under controlled dilation and shear deformations

Presentation Date and Time
October 10, 2022 (Monday) 10:50

Track / Room
Track 5 / Sheraton 2

Authors (Click on name to view author profile)

1. Wagner, Norman J. (University of Delaware, Chemical and Biomolecular Engineering)
2. Tein, Summer (University of Delaware, Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Norman J. Wagner and Summer Tein
Chemical and Biomolecular Engineering, University of Delaware, Newark, DE 19716

Speaker / Presenter 
Tein, Summer

Keywords
None

Text of Abstract
Monoclonal antibodies (mAbs) are important biotherapeutics to treat numerous human ailments, but the proteins have a natural tendency to aggregate in solution, which reduces drug formulation stability. One concerning source of instability for mAbs occurs at the air-water interface as mAbs are amphiphilic. In this work we study a well-defined NIST reference mAb (RM #8671, pI = 9.3, an IgG1 protein) with and without surfactant poloxamer P188 (Kolliphor ®, Sigma-Aldrich) in histidine buffer. Surface tension, neutron reflectometry, and interfacial shear rheology are used to characterize the adsorbed mAb interfacial layer with and without P188. Further, we study the effects of a controlled deformation history of the air-water interface using a novel interfacial rheometer (Quadrotrough (Rev. Sci. Inst. 2022, submitted) which enables both pure dilatation/compression and pure shear deformations at air-water interfaces. Using this technique, we first gain insight on isolated interfacial strain-induced behavior of NISTmAb at the air-water interface often attributed to aggregate formation in solution. Primary conclusions are made concerning the individual species and their competitive properties as follows: NISTmAb interface exhibits a strong gel-like network that adsorbs irreversibly as aggregated particles on the air-water interface. Dilatational strains cause interfacial aging as detected by surface pressure measurements, but do not show significant mesoscale differences under compression/expansion by Brewster angle microscopy. This observation suggests that the aging originates from structural rearrangement or partial unfolding of mAbs at the interface. NISTmAb exhibits high shear elasticity but is not perturbed by shear straining the interface as detected by surface pressure measurements. Overall, NISTmAb forms a highly stable network at the air-water interface with no signs of unstable desorption under the imposed interfacial dilatational and shear strain conditions. We study this interface in the presence of P188.