A novel fluorescence resonance energy transfer (FRET)-based aptasensor was proposed for carcino-embryonic antigen (CEA) detection utilizing NaYF₄:Yb³⁺, Er³⁺ upconversion nanoparticles (UCNPs) and gold nanoparticles (Au-NPs) as the energy donor and acceptor, respectively. The FRET process occurs when the single-stranded DNA modified UCNPs and Au-NPs are linked together by the CEA aptamer, which leads to the fluorescence quenching of UCNPs. However, the presence of CEA splits the above fluorescence-suppressed Au-NPs–aptamer–UCNPs sandwich complex, resulting in the fluorescence recovery of UCNPs. The recovery of fluorescence intensity is linearly correlated to the concentration of CEA in the range of 0.05–2.0 ng mL⁻¹, enabling the detection and quantification of CEA. Such a sandwich-type FRET-based assay possesses a low limit of detection (0.02 ng mL⁻¹) and satisfactory selectivity and reproducibility, indicating that this biosensor is applicable for the trace detection of the CEA protein.

中文翻译：

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基于从上转换荧光粉到金纳米粒子的荧光共振能量转移的用于癌胚抗原检测的超灵敏荧光适体传感器

利用NaYF ₄：Yb ³⁺，Er ³⁺上转换纳米颗粒（UCNPs）和金纳米颗粒（Au-NPs）作为能量，提出了一种新型的基于荧光共振能量转移（FRET）的适体传感器用于癌胚抗原（CEA）检测。供体和受体。当单链DNA修饰的UCNP和Au-NP通过CEA适配子连接在一起时，就会发生FRET过程，从而导致UCNP的荧光猝灭。但是，CEA的存在将上述荧光抑制的Au-NPs-适体-UCNPs夹心复合物分裂，导致UCNPs的荧光恢复。荧光强度的恢复与CEA浓度在0.05–2.0 ng mL ^-1范围内线性相关，可以检测和定量CEA。这种基于三明治式FRET的测定法具有低的检测限（0.02ngmL ^-1）和令人满意的选择性和再现性，表明该生物传感器适用于CEA蛋白的痕量检测。