Analysis of immunoarrays using a gold grating-based dual mode surface plasmon-coupled emission (SPCE) sensor chip

• Published in: Analyst (London) Vol. 137; no. 11; pp. 2574 - 2581
• Main Authors: Yuk, Jong Seol, Gibson, George N, Rice, James M, Guignon, Ernest F, Lynes, Michael A
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 07.06.2012
• Subjects: Analytical chemistry; Animals; Assaying; Carbocyanines - chemistry; Chemistry; Chips; Enzyme-Linked Immunosorbent Assay; Exact sciences and technology; General, instrumentation; Gold; Gold - chemistry; Human; Humans; Immunoglobulin G - analysis; Immunoglobulin G - blood; Immunoglobulin G - immunology; Mice; Miscellaneous; Plasmons; Platforms; Real time; Sensors; Surface Plasmon Resonance; Chemical analysis; Suppression; IgG; Metal; Immunological method; Molecules; Signal; Dynamics; Serum; Content analysis; Trace analysis; Human; Gold; Sample; Rodentia; System on a chip; Concentration; Chemical sensor; Surface plasmon; Real time; Biological compound; Vertebrata; Sensitivity; Mammalia; Mouse; Surface plasmon resonance; Detection; Application
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/c2an35143a

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. 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.