Sub-micron resolution surface plasmon resonance microscopy of binding kinetics under active microfluidic mixing

近年来，无论是微阵列还是芯片实验室形式的小型化生物传感研究都出现了爆炸性增长。表面等离子体共振（SPR），一个强大的生物传感方法，在这两种情况下，建立良好。大多数SPR系统基于“宏观”（mm 2或cm 2）薄膜中的传播等离子体，或基于纳米结构中的非传播局部表面等离子体（LSRP）。虽然光谱两端的系统已被广泛研究，但两者之间存在知识差距，其中表面结构及其对SPR活性金属的化学反应性和光学性质的影响尚未完全了解。这一差距很重要，因为在推动“纳米化”的过程中，科学家和工程师可能没有掌握所有要素，无法就生物传感器设计中的最佳规模水平做出明智的决定。这项研究旨在通过开发仪器和方法来填补这一空白，以观察与表面化学动力学和微流体混合的实时测量相关的亚微米尺度的SPR现象。该计划将通过一种新型成像平台来解决这些挑战，该平台能够产生与扫描电子显微镜（SEM）共同注册的高分辨率断层SPR显微镜图像，并结合主动芯片上微流体混合。该系统将能够在亚微米级的尺度上研究与金属薄膜性质相关的表面功能化和测定动力学，并允许直接测量朗缪尔等温线。这项工作将在SPR普遍应用的下一代微型生物传感器中产生广泛的影响，例如快速医疗诊断，环境监测以及制药和农业食品行业。这项研究的长期目标是使微阵列和基于芯片实验室的SPR系统能够实现目前不可能实现的密度，小型化和测量可靠性水平。

Research into miniaturized biosensing, whether in microarray or lab-on-chip formats, has seen explosive growth in recent years. Surface plasmon resonance (SPR), a powerful method for biosensing, is well established in both cases. Most SPR systems are based either on propagating plasmons in "macroscopic" (mm2 or cm2) thin-films, or on non-propagating localized surface plasmons (LSRP) in nanostructures. Though systems at both ends of the spectrum have been extensively studied, there exists a knowledge gap between the two where surface structure and its impact on chemical reactivity and optical properties of SPR-active metals are not fully understood. This gap is important to explore because, in the push to "go nano", scientists and engineers may not have all the elements in hand to make informed decisions about optimal levels of scale in biosensor design. This research aims to fill this gap by developing instrumentation & methods for observing SPR phenomena at the sub-µm scale linked to real-time measurements of surface chemistry kinetics and microfluidic mixing. The program will address these challenges with a novel imaging platform capable of producing high-resolution tomographic SPR microscopy images co-registered with that from a scanning electron microscope (SEM), and incorporating active on-chip microfluidic mixing. This system will enable the study of surface functionalization and assay kinetics in relation to metal thin-film properties, at the sub-µm level of scale, and allow direct measurement of Langmuir isotherms. The work will have wide-ranging repercussions in next-generation miniaturized biosensors in applications where SPR is prevalent such as rapid medical diagnostics, environmental monitoring, and the pharmaceutical and agri-food industries. The long term objective of this research is to enable microarray- and lab-on-chip-based SPR systems to achieve levels of density, miniaturization, and reliability of measurement not currently possible.