Determination of cardiac disease biomarker by plasmonic sandwich ELISA
Weirong Wei1, Yinyan Tang2, Huimin He2
1Department of Cardiology, Jiangxi Provincial People's Hospital, Nanchang, Jiangxi, People's Republic of China.
Insights
A novel plasmonic enzyme-linked immunosorbent assay (ELISA) enables rapid, bare-eye detection of C-reactive protein (CRP). This method aids in diagnosing acute myocardial infarction (AMI) by quantifying CRP levels more easily.
Area of Science:
- Biomedical Engineering
- Analytical Chemistry
- Biochemistry
Background:
- Acute myocardial infarction (AMI) is a critical condition caused by interrupted blood flow to the heart muscle.
- Elevated C-reactive protein (CRP) levels are a significant indicator in AMI patients, with temporal variations observed in plasma.
- Accurate quantification of CRP is crucial for identifying conditions associated with AMI.
Purpose of the Study:
- To develop a sensitive and accessible method for quantifying C-reactive protein (CRP) for acute myocardial infarction (AMI) diagnosis.
- To utilize plasmonic enzyme-linked immunosorbent assay (ELISA) for bare-eye detection of CRP.
Main Methods:
- A plasmonic ELISA was employed using an aptamer-antibody sandwich to detect CRP.
- Gold nanoparticle aggregation, indicated by a blue color change, was used for bare-eye CRP detection.
- Hydrogen peroxide (H2O2) concentration and catalase presence on the ELISA surface controlled gold growth and color differentiation.
Main Results:
- Optimal conditions for lowest detection limit involved H2O2 (200 µM), gold seed (0.2 µM), and streptavidin-catalase (1:500).
- A detection limit of 0.25 µg/mL was achieved in buffer and 0.5 µg/mL in CRP-spiked serum.
- The assay demonstrated a clear color change (blue for aggregation, red for dispersion) for visible CRP detection.
Conclusions:
- The developed plasmonic ELISA offers a simplified and effective approach for CRP level detection.
- This method facilitates easier diagnosis of AMI by providing a rapid and visual assessment of CRP concentrations.
Abstract:
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 (H2 O2 ) controls gold growth and differentiates with color changes. To achieve the lowest detection limit of CRP, H2 O2 (200 µM), gold seed (0.2 µM), and streptavidin-catalase (1:500) were found optimal. The detection limit was reached at 0.25 µg/mL, whereas it was 0.5 µg/mL in the CRP-spiked serum. This method of detection system is easier to detect the levels of CRP and helps diagnosing AMI.
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