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Strathprints serves world leading Open Access research by the University of Strathclyde, including research by the Strathclyde Institute of Pharmacy and Biomedical Sciences (SIPBS), where research centres such as the Industrial Biotechnology Innovation Centre (IBioIC), the Cancer Research UK Formulation Unit, SeaBioTech and the Centre for Biophotonics are based.

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Interaction and destabilization of a monoclonal antibody and albumin to surfaces of varying functionality and hydrophobicity

Couston, Ruairidh and Lamprou, Dimitrios and Uddin, S.J. and Van Der Walle, Christopher (2012) Interaction and destabilization of a monoclonal antibody and albumin to surfaces of varying functionality and hydrophobicity. International Journal of Pharmaceutics, 438 (1-2). pp. 71-80. ISSN 0378-5173

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Abstract

Protein products come into contact with many surfaces of differing wettability during bioprocessing, formulation and delivery, but corresponding data for the adsorbed conformations and the associated force of adhesion (Fad) is sparse. Here we have generated a series of hydrophilic and hydrophobic surfaces through silanization of silica with various terminal groups, characterizing the surface energies and droplet contact angles. Fad measured by atomic force microscopy for oriented monolayers of a human monoclonalantibody (mAb-1) clearly distinguished hydrophobic surfaces (low Fad values) from hydrophilic surfaces (high Fad values). High Fad for a methoxy capped polyethylene glycol (1000 MW) surface supports the interaction of mAb-1 with buried ethylene oxide groups, consistent with mAb-1 compression into a distorted brush border. Solid state circular dichroism showed that mAb-1 (β-sheet) or albumin (α-helical) adsorbed to bare silica beads largely retained their secondary structures. However, the extent of structural loss upon protein adsorption to functionalized silica beads could not be simply correlated to hydrophilic/hydrophobic surfaceinteraction as seen for the Fad measurements. For example, of the hydrophilic surfaces mAb-1 unfolded notably more when adsorbed to the aminopropyl surface, and of the hydrophobic surfaces both mAb-1 and albumin retained most secondary structure when adsorbed to the perfluorooctyl surface (consistent with the lipophobic perfluorinated moiety limiting exposure of the protein hydrophobic core). The data show that Fad values are not necessarily predictive of the subsequent extent of structural relaxation, and that significant structural loss is evident for proteins adsorbed to both hydrophilic or hydrophobic surfaces.