Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224, Warsaw, Poland.
Biosens Bioelectron. 2020 May 15;156:112124. doi: 10.1016/j.bios.2020.112124. Epub 2020 Feb 24.
The majority of analytical chemistry methods requires presence of target molecules directly at a sensing surface. Diffusion of analyte from the bulk towards the sensing layer is random and might be extremely lengthy, especially in case of low concentration of molecules to be detected. Thus, even the most sensitive transducer and the most selective sensing layer are limited by the efficiency of deposition of molecules on sensing surfaces. However, rapid development of new sensing technologies is rarely accompanied by new protocols for analyte deposition. To bridge this gap, we propose a method for fast and efficient deposition of variety of molecules (e.g. proteins, dyes, drugs, biomarkers, amino acids) based on application of the alternating electric field. We show the dependence between frequency of the applied electric field, the intensity of the surface enhanced Raman spectroscopy (SERS) signal and the mobility of the studied analyte. Such correlation allows for a priori selection of parameters for any desired compound without additional optimization. Thanks to the application of the electric field, we improve SERS technique by decrease of time of deposition from 20 h to 5 min, and, at the same time, reduction of the required sample volume from 2 ml to 50 μl. Our method might be paired with number of analytical methods, as it allows for deposition of molecules on any conductive surface, or a conductive surface covered with dielectric layer.
大多数分析化学方法都需要目标分子直接存在于传感表面上。分析物从主体向传感层的扩散是随机的，可能非常漫长，特别是在要检测的分子浓度较低的情况下。因此，即使是最敏感的换能器和最具选择性的传感层也受到传感表面上分子沉积效率的限制。然而，新传感技术的快速发展很少伴随着分析物沉积的新方案。为了弥补这一差距，我们提出了一种基于施加交变电场的快速有效的沉积多种分子（例如蛋白质、染料、药物、生物标志物、氨基酸）的方法。我们展示了施加电场的频率、表面增强拉曼光谱 (SERS) 信号的强度和研究分析物的迁移率之间的依赖性。这种相关性允许在无需额外优化的情况下，针对任何所需化合物预先选择参数。由于施加电场，我们将沉积时间从 20 小时缩短到 5 分钟，同时将所需的样品体积从 2 毫升减少到 50 微升，从而改进了 SERS 技术。我们的方法可以与许多分析方法结合使用，因为它允许将分子沉积在任何导电表面或覆盖有介电层的导电表面上。
