title: Preparation and characterization of nitrilotriacetic-acid-terminated self-assembled monolayers on gold surfaces for matrix-assisted laser desorption ionization-time of flight-mass spectrometry analysis of proteins and peptides.
abstract: On-target affinity capture, enrichment and purification of biomolecules improve detection of specific analytes from complex biological samples in matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) analysis. In this paper, we report a simple method for preparation of a self-assembled nitrilotriacetic acid (NTA) monolayer on gold surface which can be used as a MALDI-TOF-MS sample target specifically for recombinant oligohistidine-tagged proteins/peptides and phosphorylated peptides. The NTA functional groups are immobilized to the gold surface via the linkage of 1,8-octanedithiol which forms a self-assembled monolayer on gold. Characterization by X-ray photoelectron spectroscopy and MALDI analysis of the modified surface are described. The chemically modified surface shows strong affinity toward the analytes of interest, which allows effective removal of the common interferences, e.g. salts and detergents, and therefore leads to improved signal/noise ratio and detection limit. The use of the modified surface simplifies the sample preparation for MALDI analysis of these targeted analytes.
authors.affiliation: Department R418, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064, USA. jianwei.shen@abbott.com
authors.forename: Jianwei
authors.initials: J
authors.lastname: Shen
authors.forename: Tanveer
authors.initials: T
authors.lastname: Ahmed
authors.forename: Andrew
authors.initials: A
authors.lastname: Vogt
authors.forename: Jieyi
authors.initials: J
authors.lastname: Wang
authors.forename: Jean
authors.initials: J
authors.lastname: Severin
authors.forename: Richard
authors.initials: R
authors.lastname: Smith
authors.forename: Sally
authors.initials: S
authors.lastname: Dorwin
authors.forename: Robert
authors.initials: R
authors.lastname: Johnson
authors.forename: John
authors.initials: J
authors.lastname: Harlan
authors.forename: Tom
authors.initials: T
authors.lastname: Holzman
mesh_terms: D006046:Gold / Q000737:chemistry*; D006639:Histidine / Q000737:chemistry; D009571:Nitrilotriacetic Acid / Q000737:chemistry*; D010455:Peptides / Q000032:analysis* / Q000235:genetics; D011506:Proteins / Q000032:analysis* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013499:Surface Properties
chemical_list: D010455:Peptides; D011506:Proteins; D011994:Recombinant Proteins; D006639:Histidine; D006046:Gold; D009571:Nitrilotriacetic Acid