Determination of cardiac disease biomarker by plasmonic sandwich ELISA

Acute myocardial infarction (AMI) is the heart attack happening when the blood flow is terminated to the heart muscles. C-reactive protein (CRP) level is raising significantly in AMI patients after the onset of symptom; also, temporal variations of CRP in plasma of AMI patient have also been found. Quantifying the concentration of CRP helps to identify the condition associated with AMI. Plasmonic enzyme-linked immunosorbent assay (ELISA) was utilized here to identify CRP by the sandwich of aptamer and antibody. Bare-eye CRP detection was achieved by plasmonic ELISA through the aggregation (blue color) of gold nanoparticle in the presence of CRP, whereas in the absence of CRP, it retains its red color (dispersion). Depending on the catalase presence on the ELISA surface, hydrogen peroxide (H2O2) controls gold growth and differentiates with color changes. To achieve the lowest detection limit of CRP, H2O2 (200 mu M), gold seed (0.2 mu M), and streptavidin-catalase (1:500) were found optimal. The detection limit was reached at 0.25 mu g/mL, whereas it was 0.5 mu g/mL in the CRP-spiked serum. This method of detection system is easier to detect the levels of CRP and helps diagnosing AMI. (c) 2020 International Union of Biochemistry and Molecular Biology, Inc. Volume 00, Number 0, Pages 1-6, 2020

Automated summary

Acute myocardial infarction (AMI) patients show significantly elevated C-reactive protein (CRP) levels, and the concentration of CRP variations help identify conditions associated with AMI. Plasmonic enzyme-linked immunosorbent assay (ELISA) allows for naked-eye CRP detection based on CRP aggregation, achieving the lowest limit of CRP detection.