title: Nanoprobe-based affinity mass spectrometry for selected protein profiling in human plasma.
abstract: In recent decades, magnetic nanoparticles have emerged as a promising new platform in biomedical applications, particularly bioseparations. We have developed an immunoassay using antibody-conjugated magnetic nanoparticles as an efficient affinity probe to simultaneously preconcentrate and isolate targeted antigens from biological media. We combined this probe with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI MS) to profile proteins in diluted human plasma. The nanoparticles were designed to detect several disease-associated proteins and could be used directly in MALDI MS without an elution step, thereby facilitating multiple antigen screening and the characterization of antigen variants. Plasma antigens bound rapidly (approximately 10 min) to the antibody-conjugated nanoparticles, allowing the assay to be performed within 20 min. With sensitivity of detection in the femtomole range, the nanoscale immunoassay is superior to assays using microscale particles. We applied our method to comparative protein profiling of patients with gastric cancer and healthy individuals and found differential protein expression levels associated with the disease as well as individuals. Given the flexibility of manipulating functional groups on the nanoprobes, their low cost, robustness, and simplicity of the assay, our approach shows promise for targeted proteome profiling in clinical settings.
authors.affiliation: Institute of Chemistry and Genomic Research Center, Chemical Biology and Molecular Biophysics, Taiwan International Graduate Program, Academia Sinica, Taipei 115, Taiwan.
authors.forename: Po-Hung
authors.initials: PH
authors.lastname: Chou
authors.forename: Shu-Hua
authors.initials: SH
authors.lastname: Chen
authors.forename: Hsin-Kai
authors.initials: HK
authors.lastname: Liao
authors.forename: Po-Chiao
authors.initials: PC
authors.lastname: Lin
authors.forename: Gour-Rong
authors.initials: GR
authors.lastname: Her
authors.forename: Alan Chuan-Ying
authors.initials: AC
authors.lastname: Lai
authors.forename: Jenn-Han
authors.initials: JH
authors.lastname: Chen
authors.forename: Chun-Cheng
authors.initials: CC
authors.lastname: Lin
authors.forename: Yu-Ju
authors.initials: YJ
authors.lastname: Chen
mesh_terms: D000906:Antibodies / Q000276:immunology; D000941:Antigens / Q000276:immunology; D001798:Blood Proteins / Q000032:analysis* / Q000737:chemistry* / Q000276:immunology; D006801:Humans; D007700:Kinetics; D013058:Mass Spectrometry / Q000379:methods*; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D012680:Sensitivity and Specificity
chemical_list: D000906:Antibodies; D000941:Antigens; D001798:Blood Proteins