title: A paper-based surface-enhanced resonance Raman spectroscopic (SERRS) immunoassay using magnetic separation and enzyme-catalyzed reaction.
abstract: In this study, a novel paper-based SERRS immunoassay based on magnetic separation and alkaline phosphatase (ALP) enzyme catalyzed hydrolysis reaction was developed. By using modified antibodies conjugated to magnetic beads, capture of mouse IgG followed by addition of ALP-labeled antibodies would form a sandwich-like immunoconjugate. After magnetic separation, 5-bromo-4-chloro-3-indolyl phosphate (BCIP), a low SERRS active compound, was added as the substrate for ALP to generate a high SERRS response. Detection was conducted on a silver colloid/PVP/filter paper SERS substrate by spotting a pre-aggregated silver colloid sol onto polyvinyl pyrrolidone (PVP) modified filter paper using a semi-automatic TLC sample applicator. The optimization of the highly SERS active paper-based substrate, dynamic hydrolysis process of BCIP, quantitative detection of IgG, and selectivity of the assay was studied in detail. By taking advantage of magnetic separation in order to decrease the background interference, the selective enzyme reaction involved in producing a highly SERRS active product could detect mouse IgG from 1 to 500 ng mL(-1) with a LOD of 0.33 ng mL(-1).
authors.affiliation: State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Chen
authors.forename: Hanwen
authors.initials: H
authors.lastname: Cheng
authors.forename: Kha
authors.initials: K
authors.lastname: Tram
authors.forename: Shengfeng
authors.initials: S
authors.lastname: Zhang
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Zhao
authors.forename: Liyang
authors.initials: L
authors.lastname: Han
authors.forename: Zengping
authors.initials: Z
authors.lastname: Chen
authors.forename: Shuangyan
authors.initials: S
authors.lastname: Huan
mesh_terms: D000469:Alkaline Phosphatase / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D055910:Antibodies, Immobilized / Q000737:chemistry; D007124:Immunoenzyme Techniques / Q000295:instrumentation*; D007074:Immunoglobulin G / Q000032:analysis*; D018189:Immunomagnetic Separation / Q000295:instrumentation; D007211:Indoles / Q000378:metabolism; D057230:Limit of Detection; D059346:Magnets / Q000737:chemistry; D051379:Mice; D010209:Paper; D013059:Spectrum Analysis, Raman / Q000295:instrumentation*
chemical_list: D055910:Antibodies, Immobilized; D007074:Immunoglobulin G; D007211:Indoles; C035455:5-bromo-4-chloro-3-indoxyl phosphate; D000469:Alkaline Phosphatase