title: Probing the orientation of surface-immobilized immunoglobulin G by time-of-flight secondary ion mass spectrometry.
abstract: Static time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a powerful surface analysis technique for the characterization of protein films because of its chemical selectivity and surface sensitivity. In this study, static ToF-SIMS and principal component analysis (PCA), a multivariate data analysis method, were combined to probe the orientation of surface-immobilized immunoglobulin G (IgG). IgG orientation can enhance its ability to detect its antigen in immunoassay techniques. The IgG used in this work is the mouse monoclonal anti-human chorionic gonadotropin (anti-hCG). Anti-hCG films on different well-defined substrates have been studied using its F(ab')2 and Fc fragments as references. Atomic force microscopy was used to characterize these protein films before static ToF-SIMS analysis. The results from PCA of ToF-SIMS spectra were related to the antibody primary amino acid composition and its three-dimensional structure.
authors.affiliation: Department of Chemical Engineering, National ESCA and Surface Analysis Center for Biomedical Problems, University of Washington Engineered Biomaterials, Seattle 98195, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
authors.forename: David G
authors.initials: DG
authors.lastname: Castner
authors.forename: Buddy D
authors.initials: BD
authors.lastname: Ratner
authors.forename: Shaoyi
authors.initials: S
authors.lastname: Jiang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods; D006062:Gonadotropins / Q000032:analysis / Q000737:chemistry; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry*; D007141:Immunoglobulin Fc Fragments / Q000737:chemistry*; D007074:Immunoglobulin G / Q000737:chemistry*; D051379:Mice; D018625:Microscopy, Atomic Force / Q000379:methods; D012680:Sensitivity and Specificity; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods; D013499:Surface Properties
chemical_list: D000911:Antibodies, Monoclonal; D006062:Gonadotropins; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G