title: Characterization of adsorbed protein films by time of flight secondary ion mass spectrometry.
abstract: Time of flight secondary ion mass spectrometry (ToF-SIMS) is a useful technique in the study of adsorbed protein films because of its high surface sensitivity and chemical selectivity. However, the protein mass spectra generated by ToF-SIMS are complex fragmentation patterns of a polymer consisting of 20 different monomers (i.e., amino acids). Principal component analysis (PCA) was implemented to classify several reference positive ion protein spectra according to protein and substrate type. Furthermore, the positive ion 74/102 and 120/130 SIMS intensity ratios, radiolabeled experiments, and PCA were used to track the relative surface concentrations of bovine serum albumin and bovine fibronectin in a binary adsorption experiment. In all cases, the combination of ToF-SIMS and PCA proved capable in classifying proteins by their type (in the case of pure protein spectra) and relative surface concentration (in the case of the binary protein spectra).
authors.affiliation: National ESCA and Surface Analysis Center for Biomedical Problems, Department of Bioengineering, University of Washington, Box 351750, Seattle, WA 98195-1750, USA.
authors.forename: J B
authors.initials: JB
authors.lastname: Lhoest
authors.forename: M S
authors.initials: MS
authors.lastname: Wagner
authors.forename: C D
authors.initials: CD
authors.lastname: Tidwell
authors.forename: D G
authors.initials: DG
authors.lastname: Castner
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D003627:Data Interpretation, Statistical; D007202:Indicators and Reagents; D011138:Polytetrafluoroethylene; D011506:Proteins / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012711:Serum Albumin, Radio-Iodinated; D018629:Spectrometry, Mass, Secondary Ion
chemical_list: D007202:Indicators and Reagents; D011506:Proteins; D012711:Serum Albumin, Radio-Iodinated; D012710:Serum Albumin, Bovine; D011138:Polytetrafluoroethylene