AbstractAlpha-fetoprotein (AFP) is a reliable clinical marker of hepatocellular carcinoma (HCC). A highly sensitive fluorometric aptamer nanoprobe is described for AFP detection. It is based on fluorescence resonance energy transfer (FRET) between AFP aptamer labelled with 5-carboxyfluorescein (FAM) and palladium nanoparticles (PdNPs). The PdNPs quench the green fluorescence of the FAM-AFP aptamer via interactions between nitrogen functional groups of the AFP aptamer and PdNPs. When AFP was introduced into the FAM-AFP aptamer-PdNPs FRET system, the AFP aptamer preferentially combines with AFP. This results in a conformational change and weakens the interaction between the aptamer and the PdNPs. Thus, the fluorescence of FAM recovers. The fluorescence recovery of FAM increases linearly in the 5.0–150 ng·mL−1 AFP concentration range and has a 1.4 ng·mL−1 detection limit. The assay was applied to the analysis of spiked diluted human serum. The recovery values ranged from 98.3 to 112.9%, with relative standard deviations of <1.1%. This biosensing strategy provides a reliable and ultrasensitive protocol for the quantification of biomarkers with relevant antigens and aptamers. Graphical abstractSchematic presentation of a fluorometric aptamer nanoprobe for AFP assay based on fluorescence resonance energy transfer (FRET) between AFP aptamer labelled with 5-carboxyfluorescein (FAM) and palladium nanoparticles (PdNPs).

中文翻译：

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通过利用 5-羧基荧光素和钯纳米颗粒之间的 FRET 用于甲胎蛋白的荧光适体纳米探针

摘要 甲胎蛋白（AFP）是一种可靠的肝细胞癌（HCC）临床标志物。描述了一种用于 AFP 检测的高灵敏度荧光适体纳米探针。它基于用 5-羧基荧光素 (FAM) 标记的 AFP 适体和钯纳米粒子 (PdNP) 之间的荧光共振能量转移 (FRET)。PdNPs 通过 AFP 适体和 PdNPs 的氮官能团之间的相互作用淬灭 FAM-AFP 适体的绿色荧光。当 AFP 被引入 FAM-AFP 适配体-PdNPs FRET 系统时，AFP 适配体优先与 AFP 结合。这会导致构象变化并削弱适体和 PdNP 之间的相互作用。因此，FAM 的荧光恢复。FAM 的荧光回收率在 5.0–150 ng·mL-1 AFP 浓度范围内线性增加，并具有 1。4 ng·mL-1 检测限。该测定法用于分析加标稀释的人血清。回收率范围为 98.3% 至 112.9%，相对标准偏差 <1.1%。这种生物传感策略为量化具有相关抗原和适体的生物标志物提供了可靠且超灵敏的方案。图形摘要基于用 5-羧基荧光素 (FAM) 标记的 AFP 适体和钯纳米粒子 (PdNP) 之间的荧光共振能量转移 (FRET)，用于 AFP 测定的荧光适体纳米探针的示意图。这种生物传感策略为量化具有相关抗原和适体的生物标志物提供了可靠且超灵敏的方案。图形摘要基于用 5-羧基荧光素 (FAM) 标记的 AFP 适体和钯纳米粒子 (PdNP) 之间的荧光共振能量转移 (FRET)，用于 AFP 测定的荧光适体纳米探针的示意图。这种生物传感策略为量化具有相关抗原和适体的生物标志物提供了可靠且超灵敏的方案。图形摘要基于用 5-羧基荧光素 (FAM) 标记的 AFP 适体和钯纳米粒子 (PdNP) 之间的荧光共振能量转移 (FRET)，用于 AFP 测定的荧光适体纳米探针的示意图。