Surface plasmon-enhanced fluorescence immunosensor for monitoring cardiac troponin I

Koji Toma, Koki Oishi, Kenta Iitani, Takahiro Arakawa, Kohji Mitsubayashi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Perioperative myocardial infarction (PMI) is a common complication of non-cardiac surgery and monitoring a PMI marker, cardiac troponin I (cTnI), is helpful for the early detection of PMI. However, there is no existing biosensor for continuous measurement of cTnI. Addressing this challenge, we developed a surface plasmon-enhanced fluorescence (SPF) immunosensor for the semi-continuous measurement of cTnI. The sensor system relied on attenuated total reflection with Kretschmann configuration at the wavelength of 633 nm. An Au substrate was modified with a robust scaffold protein fused with protein G that enabled immobilization and repeated use of a capture antibody. The cTnI was measured by a sandwich assay with a fluoresce-labeled detection antibody. We also fabricated a light pipe flow-cell to collect the fluorescence efficiently. As a result, the dynamic range of the SPF immunosensor to cTnI was 3.9–100 ng/mL, and the LOD was 0.98 ng/mL. The sensor showed output only from samples containing cTnI, indicating the high selectivity. The sensor surface was regenerated by glycine-HCl (pH 2) solution, and the high reproducibility of the output (C.V. = 1.8%) was obtained in five repeated measurements of cTnI. These results indicated the potential of the SPF immunosensor for cTnI monitoring.

Original languageEnglish
Article number132132
JournalSensors and Actuators B: Chemical
Publication statusPublished - 2022 Oct 1


  • Cardiac troponin
  • Immunosensor
  • Monitoring
  • Myocardial infarction
  • Surface plasmon-enhanced fluorescence

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry


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