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 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.

中文翻译：

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等离子夹心ELISA法测定心脏病生物标志物

急性心肌梗塞 (AMI) 是当血流停止流向心肌时发生的心脏病发作。AMI患者出现症状后C反应蛋白（CRP）水平显着升高；此外，还发现了 AMI 患者血浆中 CRP 的时间变化。量化 CRP 的浓度有助于识别与 AMI 相关的状况。这里使用等离子酶联免疫吸附测定 (ELISA) 通过适体和抗体的夹心来鉴定 CRP。裸眼 CRP 检测是通过等离子体 ELISA 通过金纳米颗粒在 CRP 存在下的聚集（蓝色）实现的，而在没有 CRP 的情况下，它保持其红色（分散）。根据 ELISA 表面上存在的过氧化氢酶，过氧化氢 (H ₂ O ₂) 控制黄金的生长并通过颜色变化进行区分。为了达到 CRP 的最低检测限，发现 H ₂ O ₂ (200 µM)、金种子 (0.2 µM) 和链霉亲和素-过氧化氢酶 (1:500) 是最佳的。检测限达到 0.25 µg/mL，而在加标 CRP 的血清中为 0.5 µg/mL。这种检测系统的方法更容易检测 CRP 水平，有助于诊断 AMI。