Probing the Orientation of Surface-Immobilized Immunoglobulin G by Time-of-Flight Secondary Ion Mass Spectrometry

• Published in: Langmuir Vol. 20; no. 5; pp. 1877 - 1887
• Main Authors: Wang, Hua, Castner, David G., Ratner, Buddy D., Jiang, Shaoyi
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 02.03.2004
• Subjects: Amino Acid Sequence; Animals; Antibodies, Monoclonal - chemistry; Biosensing Techniques - methods; Gonadotropins - analysis; Gonadotropins - chemistry; Humans; Immunoglobulin Fab Fragments - chemistry; Immunoglobulin Fc Fragments - chemistry; Immunoglobulin G - chemistry; Mice; Microscopy, Atomic Force - methods; Sensitivity and Specificity; Spectrometry, Mass, Secondary Ion - methods; Surface Properties
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la035376f

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.