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

对微型生物传感的研究，无论是微阵列还是芯片上的实验室，近年来都有了爆炸式的增长。表面等离子体共振（SPR）是一种强大的生物传感方法，在这两种情况下都得到了很好的证实。大多数SPR系统要么基于“宏观”（mm2或cm2）薄膜中的传播等离子体，要么基于纳米结构中的非传播局部表面等离子体（LSRP）。尽管光谱两端的系统已经得到了广泛的研究，但两者之间存在知识差距，其中表面结构及其对sprr活性金属的化学反应性和光学性质的影响尚未完全了解。探索这一差距是很重要的，因为在推动“走向纳米”的过程中，科学家和工程师可能没有掌握所有的元素来做出关于生物传感器设计的最佳规模水平的明智决定。本研究旨在通过开发与表面化学动力学和微流体混合实时测量相关的亚微米尺度观测SPR现象的仪器和方法来填补这一空白。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层析SPR显微镜图像，并结合主动片上微流体混合。该系统将能够在亚微米尺度上研究与金属薄膜性质相关的表面功能化和分析动力学，并允许直接测量Langmuir等温线。这项工作将对SPR普遍应用的下一代小型化生物传感器产生广泛的影响，如快速医疗诊断、环境监测、制药和农业食品工业。这项研究的长期目标是使基于微阵列和芯片上实验室的SPR系统达到目前不可能实现的密度、小型化和可靠性测量水平。

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.