Grab Anna Luise, Bacher Andreas, Nesterov-Mueller Alexander, Dahint Reiner
Applied Physical Chemistry, Institute for Physical Chemistry, Heidelberg University, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany.
Clinical Cooperation Unit Molecular Hematology/Oncology, DKFZ Heidelberg and Translational Myeloma Research Group, Department of Internal Medicine V, University Hospital, 69120 Heidelberg, Germany.
Bioengineering (Basel). 2022 Feb 4;9(2):63. doi: 10.3390/bioengineering9020063.
Plasmonic biosensors are a powerful tool for studying molecule adsorption label-free and with high sensitivity. Here, we present a systematic study on the optical properties of strictly regular nanostructures composed of metallodielectric cuboids with the aim to deliberately tune their optical response and improve their biosensing performance. In addition, the patterns were tested for their potential to eliminate spurious effects from sensor response, caused by refractive index changes in the bulk solution. Shifts in the plasmonic spectrum are exclusively caused by the adsorbing molecules. For this purpose, nanopatterns of interconnected and separated cubes with dimensions ranging from 150 to 600 nm have been fabricated from poly(methyl methacrylate) using electron-beam lithography followed by metallization with gold. It is shown that a small lateral pattern size, a high aspect ratio, and short connection lengths are favorable to generate extinction spectra with well-separated and pronounced peaks. Furthermore, for selected nanostructures, we have been able to identify reflection angles for which the influence of the bulk refractive index on the position of the plasmonic peaks is negligible. It is shown that sensor operation under these angles enables monitoring of in situ biomolecule adsorption with high sensitivity providing a promising tool for high-throughput applications.
表面等离子体生物传感器是一种用于无标记且高灵敏度地研究分子吸附的强大工具。在此，我们对由金属电介质长方体组成的严格规则纳米结构的光学性质进行了系统研究，旨在有意调整其光学响应并提高其生物传感性能。此外，还测试了这些图案消除由本体溶液折射率变化引起的传感器响应中杂散效应的潜力。等离子体光谱的位移完全由吸附分子引起。为此，使用电子束光刻技术从聚甲基丙烯酸甲酯制备了尺寸范围为150至600nm的相互连接和分离的立方体纳米图案，随后用金进行金属化。结果表明，较小的横向图案尺寸、高纵横比和短连接长度有利于产生具有良好分离且明显峰的消光光谱。此外，对于选定的纳米结构，我们能够确定本体折射率对等离子体峰位置的影响可忽略不计的反射角。结果表明，在这些角度下进行传感器操作能够以高灵敏度监测原位生物分子吸附，为高通量应用提供了一种有前途的工具。
