A spectrum-resolved dual-color electrochemiluminescence (ECL) immunoassay was designed and implemented to simultaneously detect carcinoembryonic antigen (CEA) and alpha fetoprotein (AFP) with CdTe (λ_max = 776 nm) and CdSe (λ_max = 550 nm) nanocrystals (NCs) as ECL tags. The CdTe and CdSe NCs were labeled with respective probe antibodies (Ab₂) of CEA and AFP, respectively, and then immobilized onto the working electrode surface via sandwich-type immunoreactions. Both CdTe and CdSe NCs within the NCs immunocomplexes can be electrochemically reduced and simultaneously give off monochromatic ECL emissions in the near-infrared and greenish regions, respectively, when (NH₄)₂S₂O₈ was used as a cathodic ECL coreactant. The ECL spectra of the two surface-confined NCs were well separated and had no cross energy-transfer interactions, which made the dual-color immunoassay highly selective and sensitive toward respective target analytes. With the proposed ECL biosensor, CEA and AFP were simultaneously detected and quantified with an extremely low detection limit of 1 pg/mL for CEA and 10 fg/mL for AFP, respectively. This work demonstrated the probability of performing multianalyte assays via a spectrum-resolved ECL strategy with improved sensitivity and signal-to-noise ratio as compared to NCs-based fluorescent multianalyte assays.

中文翻译：

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光谱解析双色电化学发光免疫分析法同时检测以纳米晶体为标记的两个目标

设计并实施了光谱分辨双色电化学发光（ECL）免疫测定法，以同时检测具有CdTe（_λmax = 776 nm）和CdSe（_λmax = 550 nm）纳米晶体的癌胚抗原（CEA）和甲胎蛋白（AFP）（ NCs）作为ECL标签。CdTe和CdSe NCs分别用CEA和AFP的各自探针抗体（Ab ₂）标记，然后通过夹心型免疫反应固定在工作电极表面上。当（NH ₄）₂ S ₂ O发生时，NCs免疫复合物中的CdTe和CdSe NCs均可被电化学还原，并同时在近红外和绿色区域同时发出单色ECL发射。₈用作阴极ECL共反应剂。两个表面受限的NC的ECL光谱被很好地分离并且没有交叉的能量转移相互作用，这使得双色免疫测定法具有很高的选择性并且对相应的目标分析物敏感。使用提出的ECL生物传感器，可以同时检测和定量CEA和AFP，极低的检出限分别为：CEA 1 pg / mL和AFP 10 fg / mL。这项工作证明了与基于NCs的荧光多分析物测定相比，通过光谱解析ECL策略进行多分析物测定的可能性，灵敏度和信噪比得到了改善。