title: Comparison of different protein immobilization methods on quartz crystal microbalance surface in flow injection immunoassay.
abstract: In this study, a quartz crystal microbalance (QCM) system operated repetitively in flow injection analysis (FIA) mode, is reported. Four immobilization approaches of seven different methods include: (i) physical adsorption; (ii) two thioamine thiolation methods, using cysteamine and cystamine for gold chemisorption and further coupling; (iii) two oxidized dextran spacer methods, coupling of cysteamine and cystamine thiolated QCM surface with periodate-oxidized dextran for further Schiff acid-base reaction; and (iv) two thiol-gold chemisorption-based self-assembled monolayer (SAM), applying short-chain, C(3), and long-chain, C(11), mercapto fatty acids to insolubilize human serum albumin (HSA) on QCM surface. Effects of these protein immobilization methods on FIA immunoassay of anti-HSA were compared. At the 0.01 mg/ml anti-HSA level, the lowest analyte concentration tested, the SAM using 11-mercaptoundecanoic acid as QCM surface activating agent generated a larger frequency shift than the other immobilization methods. This implied that the use of thiolated long-chain fatty acid constructed as self-assembled monolayer may thereby potentially be a useful protein immobilization method in QCM-FIA application.
authors.affiliation: Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan, Republic of China. ycliu@dragon.nchu.edu.tw
authors.forename: Y C
authors.initials: YC
authors.lastname: Liu
authors.forename: C M
authors.initials: CM
authors.lastname: Wang
authors.forename: K P
authors.initials: KP
authors.lastname: Hsiung
mesh_terms: D000042:Absorption; D000818:Animals; D015374:Biosensing Techniques; D003176:Complement C3 / Q000737:chemistry; D003460:Crystallization; D003538:Cystamine / Q000737:chemistry; D003543:Cysteamine / Q000737:chemistry; D017743:Equipment Reuse; D005227:Fatty Acids / Q000737:chemistry; D017022:Flow Injection Analysis / Q000379:methods*; D006041:Goats / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D011791:Quartz; D012709:Serum Albumin / Q000737:chemistry / Q000276:immunology; D013499:Surface Properties
chemical_list: D003176:Complement C3; D005227:Fatty Acids; D012709:Serum Albumin; C016173:undecanoic acid; D011791:Quartz; D003543:Cysteamine; D003538:Cystamine