A common strategy to improve the sensitivity of a biosensor for the detection of a low abundance analyte is to preconcentrate the analyte molecules before detection. A dual-functional gold–iron oxide core–satellite hybrid nanoparticle structure is proposed in this work to overcome the drawbacks of traditional sample pretreatment methods and the methods using non-magnetic nanomaterials for sample pretreatment. The new dual-functional hybrid nanoparticle structure can simultaneously serve as a signal reporter of a biorecognition event and a preconcentrator of a target at an extremely low concentration in a nanoplasmonic biosensor. By utilizing a fiber optic nanogold-linked sorbent assay in the fiber optic particle plasmon resonance (FOPPR) biosensor and an arbitrary DNA sequence as a target, we have demonstrated that the use of the new hybrid nanoparticle structure with magnetic preconcentration improves the limit of detection (LOD) for the DNA by 18 times as compared to the same method without magnetic preconcentration, so that the LOD for detecting the DNA can be as low as 2.6 fM. The new hybrid nanoparticle structure is easy to prepare and its use in the high-sensitivity and low-cost FOPPR biosensor provides vast opportunities in point-of-care applications.

中文翻译：

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双功能金-氧化铁核-卫星混合纳米粒子通过纳米等离子体和预浓缩效应增强生物传感器的灵敏度

提高生物传感器检测低丰度分析物灵敏度的常用策略是在检测前预浓缩分析物分子。本工作提出了一种双功能的金-氧化铁核-卫星混合纳米颗粒结构，以克服传统样品预处理方法和使用非磁性纳米材料进行样品预处理的方法的缺点。新的双功能混合纳米颗粒结构可以同时作为生物识别事件的信号报告器和纳米等离子体生物传感器中极低浓度的目标的预浓缩器。通过在光纤粒子等离子共振 (FOPPR) 生物传感器中利用光纤纳米金连接的吸附剂测定和任意 DNA 序列作为目标，我们已经证明，与没有磁性预浓缩的相同方法相比，使用具有磁性预浓缩的新型混合纳米颗粒结构将 DNA 的检测限 (LOD) 提高了 18 倍，因此检测 DNA 的 LOD 可以为低至 2.6 fM。新的混合纳米颗粒结构易于制备，其在高灵敏度和低成本 FOPPR 生物传感器中的使用为床旁护理应用提供了巨大的机会。