title: Human immunoglobulin adsorption investigated by means of quartz crystal microbalance dissipation, atomic force microscopy, surface acoustic wave, and surface plasmon resonance techniques.
abstract: Time-resolved adsorption behavior of a human immunoglobin G (hIgG) protein on a hydrophobized gold surface is investigated using multitechniques: quartz crystal microbalance/dissipation (QCM-D) technique; combined surface plasmon resonance (SPR) and Love mode surface acoustic wave (SAW) technique; combined QCM-D and atomic force microscopy (AFM) technique. The adsorbed hIgG forms interfacial structures varying in organization from a submonolayer to a multilayer. An "end-on" IgG orientation in the monolayer film, associated with the surface coverage results, does not corroborate with the effective protein thickness determined from SPR/SAW measurements. This inconsistence is interpreted by a deformation effect induced by conformation change. This conformation change is confirmed by QCM-D measurement. Combined SPR/SAW measurements suggest that the adsorbed protein barely contains water after extended contact with the hydrophobic surface. This limited interfacial hydration also contributed to a continuous conformation change in the adsorbed protein layer. The viscoelastic variation associated with interfacial conformation changes induces about 1.5 times overestimation of the mass uptake in the QCM-D measurements. The merit of combined multitechnique measurements is demonstrated.
authors.affiliation: Biosensors group, Interuniversity Microelectronics Center (IMEC), Kapeldreef 75, 3001 Leuven, Belgium. Cheng.zhou@imec.be
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhou
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Friedt
authors.forename: Angelina
authors.initials: A
authors.lastname: Angelova
authors.forename: Kang-Hoon
authors.initials: KH
authors.lastname: Choi
authors.forename: Wim
authors.initials: W
authors.lastname: Laureyn
authors.forename: Filip
authors.initials: F
authors.lastname: Frederix
authors.forename: Laurent A
authors.initials: LA
authors.lastname: Francis
authors.forename: Andrew
authors.initials: A
authors.lastname: Campitelli
authors.forename: Yves
authors.initials: Y
authors.lastname: Engelborghs
authors.forename: Gustaaf
authors.initials: G
authors.lastname: Borghs
mesh_terms: D000327:Adsorption; D003460:Crystallization; D006046:Gold / Q000737:chemistry; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D007074:Immunoglobulin G / Q000737:chemistry*; D007700:Kinetics; D018625:Microscopy, Atomic Force / Q000379:methods*; D011791:Quartz / Q000737:chemistry*; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000379:methods*; D013499:Surface Properties; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D007074:Immunoglobulin G; D014867:Water; D011791:Quartz; D006046:Gold