Leibniz Institut für Analytische Wissenschaften-ISAS-e.V., Bunsen-Kirchhoff-Straße 11, 44139 Dortmund, Germany.
Experimental Physics, TU Dortmund University, 44227 Dortmund, Germany.
Sensors (Basel). 2023 Apr 26;23(9):4283. doi: 10.3390/s23094283.
Imaging wide-field surface plasmon resonance (SPR) microscopy sensors based on polyacrylic acid polyelectrolyte brushes (PAA PEBs) were designed to enhance the sensitivity of nano-object detection. The switching behavior of the PAA PEBs against changes in the pH values was investigated by analyzing the chemical, morphological, optical, and electrical properties. At pH ~1, the brushes collapse on the surface with the dominance of carboxylic groups (COOH). Upon the increase in the pH to nine, the switching process completes, and the brushes swell from dissociating most of the COOH groups and converting them into COO- groups. The domination of the negatively charged COO- groups increases the electrostatic repulsion in the polymer chains and stretches the brushes. The sensitivity of the SPR sensing device was investigated using a theoretical approach, as well as experimental measurements. The signal-to-noise ratio for a Au layer increases from six to eighteen after coating with PAA PEBs. In addition, the linewidth of the recorded image decreases from six pixels to five pixels by using the Au-PAA layers, which results from the enhanced spatial resolution of the recorded images. Coating a Au-layer with PAA PEBs enhances the sensitivity of the SPR sensing device, and improves the spatial resolution of the recorded image.
基于聚丙烯酸聚电解质刷（PAA PEBs）的宽场表面等离子体共振（SPR）显微镜传感器成像设计用于提高纳米物体检测的灵敏度。通过分析化学、形态、光学和电学特性来研究 PAA PEBs 对 pH 值变化的开关行为。在 pH 值约为 1 时，刷子在带有羧酸基团（COOH）占主导地位的表面上坍塌。当 pH 值增加到九时，开关过程完成，刷子从解离大多数 COOH 基团并将其转化为 COO-基团中膨胀。带负电荷的 COO-基团的主导地位增加了聚合物链中的静电排斥力并拉伸了刷子。使用理论方法和实验测量研究了 SPR 传感装置的灵敏度。涂覆 PAA PEBs 后，Au 层的信噪比从六增加到十八。此外，通过使用 Au-PAA 层，记录图像的线宽从六个像素减少到五个像素，这是由于记录图像的空间分辨率提高所致。用 PAA PEBs 涂覆 Au 层可以提高 SPR 传感装置的灵敏度，并提高记录图像的空间分辨率。
