Nano- and micro-plasmonics; towards scanning probe SPR microscopy and plasmonic sensors integrated to multi-well plate readers

该研究计划旨在开发基于表面等离子体共振(SPR)特性的生物分析工具，用于检测生物标记物。推动该计划方向的两个主要目标是：1)开发用于检测一组生物标志物的多重生物分析工具；2)建立一种能够以空间分辨率测量参与癌症信号机制的细胞外蛋白浓度的分析技术。纳米和微复制技术的最新发展为光学生物传感提供了新的机会，这满足了开发这些重要生物分析工具的要求。因此，将开展基于纳米孔阵列和多孔板的纳米等离子体传感器的研究。纳米孔阵列对生物分子表现出高度的敏感性，通过简单的吸光度测量进行分析，并适合集成到96孔阵列格式中。因此，几种趋化因子的定量将在几分钟内完成。这项技术不仅限于趋化因子的分析，还可以应用于其他生物标记物的面板。趋化因子是一种信使蛋白，在癌症患者血清中呈高水平表达，可能与肿瘤的生长和转移有关。由于它们在肿瘤生长和转移中的作用尚不完全清楚，因此，一种能够检测它们在细胞外基质中的存在和浓度的工具可能有助于阐明它们的功能。因此，扫描探针SPR显微镜将被开发来以空间分辨率测量健康和癌细胞释放的趋化因子的浓度。扫描探针SPR显微镜，即AFM针尖上的SPR微型传感器，是基于微米长的金属薄膜的性质的。这些微等离子体结构表现出对折射率的敏感性，并可用于使用标准的SPR生物传感原理来检测趋化因子。在镀金的AFM针尖上固定针对趋化因子的抗体，目的是用扫描探针SPR显微镜进行亚细胞分辨的趋化因子的定量。

The research program aims at developing bioanalytical tools, based on the properties of surface plasmon resonance (SPR) for the detection of biomarkers. Two main objectives are motivating the direction of the program: 1) the development of multiplexed bioanalytical tools for the detection of a panel of biomarkers and 2) establishing an analytical technique capable of measuring with spatial resolution the concentration of extracellular proteins involved in the signaling mechanism of cancer. The recent developments in nano- and micro-plamonics enable new opportunities in optical biosensing, which fulfills the requirements of developing these important bioanalytical tools. Thus, research will be performed to integrate nano-plasmonic sensors based on nanohole arrays with multi-well plates. Nanohole arrays exhibit high sensitivity to biomolecules, are analyzed with a simple absorbance measurement and are suited for the integration into a 96-well array format. Thereby, the quantification of several chemokines will be accomplished within minutes. This technique is not restricted to the analysis of chemokines and could be applied to other panels of biomarkers. Chemokines are messenger proteins, which exhibit high levels in cancer patient's serum and may be involved in cancer growth and metastasis. Since their role is not perfectly understood in cancer growth and metastasis, a tool that can detect their presence and concentration in the extracellular matrix could help elucidate their function. Thus, scanning probe SPR microscopy will be developed to measure with spatial resolution the concentration of chemokines released by healthy and cancerous cells. Scanning probe SPR microscopy, i.e. a SPR micro-sensor on an AFM tip, is based on the properties of metal films of micrometer length. These micro-plasmonic structures exhibit sensitivity to refractive index and can be applied to detect chemokines using standard principles of SPR biosensing. Immobilizing an antibody selective for a chemokine on the gold-coated AFM tip aims at the quantification of chemokines with sub-cellular resolution with scanning probe SPR microscopy.