The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China; Research Institute of Xi'an Jiaotong University, Floor 5, Block A, Jiangning Mansion, No. 328, Wenming Road, Xiaoshan District, Hangzhou, Zhejiang Province, China.
The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China.
Anal Chim Acta. 2022 Aug 15;1221:340129. doi: 10.1016/j.aca.2022.340129. Epub 2022 Jun 27.
The etching of gold nanorods/nanobipyramid, or silver-coated nanorods/nanobipyramid inducing plasmon changes represents an efficient strategy to improve the performance of enzyme-linked immunosorbent assay (ELISA). However, the effect of shape on the sensitivity was negligible, especially the thickness of coated silver shell. Here, we propose a plasmonic ELISA for multi-colorimetric detection of CRP based on the etching of Ag-coated Au nanobipyramid (Au NBP@Ag). The effect of silver shell thickness on the sensitivity of plasmon peak shifting was investigated by experiments and DDA calculations. The relationship between the Ag shell thickness and the sensitivity of plasmon peak shifting was obtained. Our results reveal that the thickness of coated Ag shell acts as a key factor in the multi-color change of Au NBP@Ag etching. It is found that Au NBP@Ag with medium Ag shell thickness and rod-like shape has the higher sensitivity and is suitable for sensing. At the optimized most sensitive Ag shell, the detection limit of proposed plasmonic ELISA for CRP was determined to be 0.09 ng/mL with a spectrometer in the range from 0.09 ng/mL to 25 ng/mL. Importantly, the visual detection limit was 0.78 ng/mL, which allows the differential diagnosis with the naked eye. Compared with traditional ELISA with the monochromatic intensity variations, the multi-color ELISA proposed in this study has a large linear range and rich color variation for high-sensitivity and naked-eye semi-quantitative detection.
金纳米棒/纳米双锥体的刻蚀或银包覆的纳米棒/纳米双锥体诱导等离子体变化是提高酶联免疫吸附测定（ELISA）性能的有效策略。然而，形状对灵敏度的影响可以忽略不计，尤其是银壳的厚度。在这里，我们提出了一种基于银包覆金纳米双锥体（Au NBP@Ag）刻蚀的等离子体 ELISA 用于 CRP 的多色检测。通过实验和 DDA 计算研究了银壳厚度对等离子体峰位移灵敏度的影响。获得了银壳厚度与等离子体峰位移灵敏度之间的关系。我们的结果表明，包覆银壳的厚度是 Au NBP@Ag 刻蚀多色变化的关键因素。研究发现，具有中等银壳厚度和棒状形状的 Au NBP@Ag 具有更高的灵敏度，适合传感。在优化的最灵敏的银壳下，所提出的等离子体 ELISA 对 CRP 的检测限在 0.09ng/mL 时用分光光度计在 0.09ng/mL 至 25ng/mL 的范围内确定为 0.09ng/mL。重要的是，视觉检测限为 0.78ng/mL，允许用肉眼进行鉴别诊断。与传统 ELISA 中单色强度变化相比，本研究提出的多色 ELISA 具有较大的线性范围和丰富的颜色变化，用于高灵敏度和肉眼半定量检测。
