School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China.
School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China.
Anal Chem. 2022 Jul 12;94(27):9919-9926. doi: 10.1021/acs.analchem.2c01986. Epub 2022 Jun 24.
Photonic crystals (PCs) have emerged as a promising electrochemiluminescence (ECL) matrix in the domain of immunoassay. Making maximum use of light manipulation properties of PCs is highly desired for improving the sensitivity. In this work, we proposed a band-edge effect-induced ECL enhancement strategy based on silica inverse opal PCs (SIOPCs). By fine-tuning the lattice constant and carefully calibrating the stopband position, we found that the band edge of the stopband exerted significant influences on the ECL intensity and spectral distribution. The high density of states at the blue edge of the photonic band gap increased the radiative transition probability of ECL emitters and enhanced the photon extraction during propagation, giving rise to ∼20-fold ECL signal amplification accompanied by a redistributed ECL spectrum for the Ru(bpy)-TPrA system. In combination with the intrinsic structural superiority, like large specific surface area and interconnected macropores, the developed SIOPC electrode was successfully applied in constructing a sandwich-type immunosensor. The fabricated immunosensor displayed a very low detection limit of 0.032 pg/mL and a wide linear range of 0.1 pg/mL-150 ng/mL for a carcinoembryonic antigen assay, showing its potential application in disease diagnosis.
光子晶体（PCs）在免疫分析领域作为一种很有前途的电致化学发光（ECL）基质而出现。充分利用 PCs 的光操纵特性，对于提高灵敏度是非常理想的。在这项工作中，我们提出了一种基于二氧化硅反蛋白石光子晶体（SIOPCs）的带边效应诱导的 ECL 增强策略。通过微调晶格常数和仔细校准阻带位置，我们发现阻带的能带边缘对 ECL 强度和光谱分布有显著影响。光子带隙的蓝边处的高密度态增加了 ECL 发射器的辐射跃迁概率，并增强了在传播过程中的光子提取，从而使 Ru（bpy）-TPrA 体系的 ECL 信号放大了约 20 倍，同时 ECL 光谱也发生了重新分布。结合其内在的结构优势，如大的比表面积和相互连通的大孔，所开发的 SIOPC 电极成功地应用于构建三明治型免疫传感器。所制备的免疫传感器在癌胚抗原检测中表现出非常低的检测限为 0.032 pg/mL 和宽线性范围为 0.1 pg/mL-150 ng/mL，显示出其在疾病诊断中的潜在应用。
