title: Sulfonate group-modified FePtCu nanoparticles as a selective probe for LDI-MS analysis of oligopeptides from a peptide mixture and human serum proteins.
abstract: Bare FePtCu nanoparticles (NPs) are first prepared for laser desorption/ionization mass spectroscopy (LDI-MS) analysis as affinity probes to selectively trap oppositely charged analytes from a sample solution. Our present results demonstrate bare FePtCu NPs to be a potentially useful matrix for surface-assisted laser desorption/ionization mass spectroscopy (SALDI-MS), for the analysis of small proteins and peptides. The upper detectable mass range of peptides was approximately 5 kDa, and the detection limit for peptides approximately 5 fmol. Sulfonate group-modified FePtCu nanoparticles (FePtCu-SO(3)(-) NPs), with ionization being independent of the solution pH, can interact with a positively charged analyte, and the analyte-bound NPs can be separated from the reaction supernatant by centrifugation or an external magnetic field. An oligopeptide, Gly-Gly-Tyr-Arg (GGYR) from an oligopeptide mixture containing Asp-Asp-Asp-Asp (DDDD), Gly-Gly-Gly-Gly (GGGG) and GGYR, was detected using SALDI-MS with FePtCu-SO(3)(-) NPs employing electrostatic interaction. Furthermore, FePtCu-SO(3)(-) NPs can detect lysozyme (Lyz) in human serum through the electrostatic attraction between positively charged Lyz and FePtCu-SO(3)(-) NPs at pH 8, while detection of negatively charged albumin in human serum is not possible.
authors.affiliation: Department of Applied Chemistry, Kansai University, Suita, Osaka 564-8680, Japan.
authors.forename: Hideya
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Tarui
authors.initials: T
authors.lastname: Akira
authors.forename: Takehiro
authors.initials: T
authors.lastname: Watanabe
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Nozaki
authors.forename: Tetsu
authors.initials: T
authors.lastname: Yonezawa
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Arakawa
mesh_terms: D001798:Blood Proteins / Q000737:chemistry*; D003300:Copper / Q000737:chemistry; D006801:Humans; D007501:Iron / Q000737:chemistry; D013058:Mass Spectrometry; D053768:Metal Nanoparticles / Q000032:analysis* / Q000737:chemistry / Q000648:ultrastructure; D019216:Metals, Heavy / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D009842:Oligopeptides / Q000032:analysis* / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry; D013451:Sulfonic Acids / Q000737:chemistry*
chemical_list: D001798:Blood Proteins; D019216:Metals, Heavy; D009842:Oligopeptides; D010455:Peptides; D013451:Sulfonic Acids; D010984:Platinum; D003300:Copper; D007501:Iron