title: Analysis of immunoarrays using a gold grating-based dual mode surface plasmon-coupled emission (SPCE) sensor chip.
abstract: We have developed a novel dual mode immunoassay platform that combines the advantages of real-time, label free measurement of surface plasmon resonance (SPR) and the highly directional surface plasmon-coupled emission (SPCE) using a gold grating-based sensor chip. Since only fluorophore-labeled analyte molecules that are close to the metal surface of the sensor chip will couple to the surface plasmon, SPCE detection is highly surface-specific leading to background suppression and increased sensitivity. Theoretical calculations were done to find SPR and SPCE angles for a sensor chip optimized for Alexa Fluor 647. We have confirmed the SPR and SPCE responses on the dual mode sensor chip using Alexa Fluor 647 labeled anti-mouse IgG. Signal fluctuation of the dual mode sensor chip reader was below 1.2% and 0.8% for SPR and SPCE, respectively. The SPR response in this configuration showed a minimum detection level of 1 μg ml(-1), and the SPCE response showed a minimum detection level of 1 ng ml(-1) for the same sample. A range of human IgG concentrations in human serum was also analyzed with the dual mode sensor chip. The SPCE measurement is more sensitive than the SPR real-time measurement, and substantially extends the dynamic range of the assay platform, as well as enabling independent measurements of co-localized analytes on the same sensor chip region of interest. Since this assay platform is capable of measuring more than 1000 spatially encoded regions of interest on a 1 cm(2) sensor chip, it has the potential for high-content analyses of biological samples with both research and clinical applications.
authors.affiliation: Department of Molecular and Cell Biology, Storrs, CT 06269-3125, USA.
authors.forename: Jong Seol
authors.initials: JS
authors.lastname: Yuk
authors.forename: George N
authors.initials: GN
authors.lastname: Gibson
authors.forename: James M
authors.initials: JM
authors.lastname: Rice
authors.forename: Ernest F
authors.initials: EF
authors.lastname: Guignon
authors.forename: Michael A
authors.initials: MA
authors.lastname: Lynes
mesh_terms: D000818:Animals; D002232:Carbocyanines / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis* / Q000097:blood / Q000276:immunology; D051379:Mice; D020349:Surface Plasmon Resonance
chemical_list: C569686:Alexa Fluor 647; D002232:Carbocyanines; D007074:Immunoglobulin G; D006046:Gold