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，用于检测生物标志物。两个主要目标是推动该计划的方向：1）开发用于检测一组生物标志物的多路生物分析工具，2）建立一种能够以空间分辨率测量参与癌症信号传导机制的细胞外蛋白浓度的分析技术。纳米和微米等离子体学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，将进行研究以将基于纳米孔阵列的纳米等离子体传感器与多孔板集成。纳米孔阵列对生物分子表现出高灵敏度，用简单的吸光度测量进行分析，并且适合于集成到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。该技术不限于分析趋化因子，并且可以应用于其他生物标志物组。趋化因子是一种信使蛋白，在癌症患者血清中表现出高水平，并可能参与癌症的生长和转移。由于它们在癌症生长和转移中的作用尚未完全了解，因此可以检测它们在细胞外基质中的存在和浓度的工具可以帮助阐明它们的功能。因此，将开发扫描探针SPR显微镜，以测量健康和癌细胞释放的趋化因子的浓度。扫描探针SPR显微术，即AFM针尖上的SPR微传感器，是基于微米长度的金属膜的性质。这些微等离子体结构表现出对折射率的敏感性，并且可以应用于使用SPR生物传感的标准原理来检测趋化因子。将对趋化因子具有选择性的抗体固定在金包被的AFM针尖上，目的是用扫描探针SPR显微镜以亚细胞分辨率定量趋化因子。

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.