Hybrid nanocomposite particles composed of a gold core coated with a europium(III)-chelate fluorophore-doped silica shell (AuNPs@SiO₂–Eu³⁺) have been synthesized and applied as antibody labels in lateral flow immunoassay (LFIA) devices for the determination of human thyroid stimulating hormone (hTSH). Labeling of monoclonal anti-hTSH antibodies with AuNPs@SiO₂–Eu³⁺ nanocomposites allows for both colorimetric and fluorometric observation of assay results on LFIA devices, relying on visible light absorption due to the localized surface plasmon resonance of the Au-core and the fluorescence emission of the Eu(III)-chelate-modified shell under UV hand lamp irradiation (365 nm), respectively. The possibility for a dual signal readout provides an attractive alternative for LFIAs: instantaneous naked eye observation of the AuNP colorimetric signal as in conventional LFIAs for hypothyroidism detection, and more sensitive fluorescence detection to assess hyperthyroidism. The limits of detection (LOD) for naked eye observation of LFIA devices are 5 μIU mL⁻¹ and 0.1 μIU mL⁻¹ for the colorimetric and fluorimetric detection, respectively. Using the fluorescence detection scheme in combination with a smartphone and digital color analysis, a quantitative linear relationship between the red intensity and the logarithmic concentration of hTSH was observed (R² = 0.988) with an LOD of 0.02 μIU mL⁻¹. Finally, LFIA devices were effectively applied for detecting hTSH in spiked diluted human serum with recovery values between 100–116%.

中文翻译：

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金纳米粒子核– op（iii）螯合物荧光团掺杂的二氧化硅壳杂化纳米复合材料，用于双信号读数的人甲状腺刺激激素的侧向流免疫测定†

涂覆有铕（金芯组成的混合纳米复合粒子III）螯合物的荧光团-掺杂二氧化硅壳（金纳米粒子@的SiO ₂ -Eu ³⁺已被合成并作为侧流免疫测定抗体的标签施加）（LFIA）用于设备人体甲状腺刺激素（hTSH）的测定。用AuNPs @ SiO ₂ –Eu ³⁺纳米复合材料标记单克隆抗hTSH抗体，可以通过比色法和荧光法观察LFIA装置上的检测结果，这取决于Au-核和表面的局部表面等离振子共振，从而吸收了可见光。 Eu（III）的荧光发射）-螯合物改性的壳分别在紫外线手灯照射下（365 nm）。双重信号读数的可能性为LFIA提供了一种有吸引力的替代方法：与常规LFIA中的甲状腺功能减退症一样，可以用肉眼即时观察AuNP比色信号，并且可以通过更灵敏的荧光检测来评估甲状腺功能亢进。LFIA设备用肉眼观察的检测限（LOD）对于比色和荧光检测分别为5μIUmL ^-1和0.1μIUmL ^-1。使用荧光检测方案结合智能手机和数字颜色分析，观察到红色强度与hTSH的对数浓度之间存在定量线性关系（R ²= 0.988）的LOD为0.02μIUmL ^-1。最后，LFIA设备有效地用于检测加标稀释人血清中的hTSH，回收率在100–116％之间。