Department of Physics, Faculty of Science, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.
Functional Nanotechnology Devices Laboratory, Institute of Nanoscience and Nanotechnology, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia.
Biosensors (Basel). 2022 Dec 3;12(12):1124. doi: 10.3390/bios12121124.
Surface plasmonic sensors have received considerable attention, found extensive applications, and outperformed conventional optical sensors. In this work, biopolymer chitosan (CS) was used to prepare the bilayer structure (CS/Au) of a plasmonic refractive index sensor for dopamine (DA) detection. The sensing characteristics of the developed plasmonic sensor were evaluated. Increasing DA concentrations significantly shifted the SPR dips. The sensor exhibited stability and a refractive index sensitivity of 8.850°/RIU in the linear range 0.1 nM to 1 µM with a detection limit of 0.007 nM and affinity constant of 1.383 × 10 M. The refractive index and thickness of the CS/Au structure were measured simultaneously by fitting the obtained experimental findings to theoretical data based on Fresnel equations. The fitting yielded the refractive index values (1.5350 ± 0.0001) and (0.0150 ± 0.0001) for the CS layer contacting 0.1 nM of DA, and the thickness, was (15.00 ± 0.01) nm. Then, both and values increased by increasing DA concentrations. In addition, the changes in the FTIR spectrum and the variations in sensor surface roughness and structure obtained by AFM analysis confirmed DA adsorption on the sensing layer. Based on these observations, CS/Au bilayer has enhanced the performance of this plasmonic sensor, which showed promising importance as a simple, low-cost, and reliable platform for DA sensing.
表面等离子体激元传感器受到了广泛关注，得到了广泛的应用，并优于传统的光学传感器。在这项工作中，生物聚合物壳聚糖（CS）被用于制备等离子体折射率传感器的双层结构（CS/Au），用于多巴胺（DA）检测。评估了所开发的等离子体传感器的传感特性。随着 DA 浓度的增加，SPR 峰明显移动。该传感器在 0.1 nM 至 1 µM 的线性范围内表现出稳定性和折射率灵敏度为 8.850°/RIU，检测限为 0.007 nM，亲和常数为 1.383×10 M。通过将获得的实验结果拟合到基于菲涅耳方程的理论数据，同时测量 CS/Au 结构的折射率和厚度。拟合得到与接触 0.1 nM DA 的 CS 层相关的折射率值为 (1.5350 ± 0.0001) 和 (0.0150 ± 0.0001)，厚度为 (15.00 ± 0.01) nm。然后，随着 DA 浓度的增加， 和 值都增加了。此外，傅里叶变换红外光谱的变化以及 AFM 分析得到的传感器表面粗糙度和结构的变化证实了 DA 吸附在传感层上。基于这些观察结果，CS/Au 双层增强了这种等离子体传感器的性能，作为一种简单、低成本和可靠的 DA 传感平台具有重要的应用前景。
