Microfluidic tools for improved sensing and dispensing

用于改进传感和分配的微流体工具

• 批准号: RGPIN-2016-06189
• 负责人: Sullivan, Pierre
• 金额: $ 2.11万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=666171
• 关键词: Microfluidic; tools; improved; sensing; dispensing

Digital Microfluidics (DMF) enables the control and manipulation of minute and discrete units of fluid from the picoliter to microliter scale and offers the long-term potential for fast personalized diagnosis for patients, for example, to track obesity treatment effectiveness. In typical closed configurations, droplets are confined between two parallel substrates. A bottom substrate defining a grid of electrodes, and a top electrode to act as an electrical ground. By applying an electric field between the electrodes, droplets can be orchestrated and manipulated, such as to be made to merge, split, or protrude into smaller droplets. Due to the discrete operating procedure, liquid control and handling that is usually associated with biochemical protocols and assays can be fully emulated by the digital microfluidic device. Droplets can be used as isolated transport capsules, and at the same time function as microreactors for chemical reactions to take place. Fluid volumes can be drastically decreased and diffusion and reaction rates increased. In this way, DMF devices leverage phenomena that are dominant at the microscale instead of working against them like many continuous flow devices. Common detection methods, such as optical detection, have become harder to be integrated with microdevices, especially by virtue of the need for portable, point-of-care applications. While the size of the components related to fluidic control and handling has been dramatically reduced, similar downscaling of external optical instruments for chemical reaction detection is more difficult. Electrochemical detection is a very practicable technique for DMF devices. It can be integrated due to simple sensor designs compatible with microfabrication technologies. Also, electrochemical transducers can be combined with inexpensive instrumentation, and have low power consumption, high sensitivity, low detection limits, and adjustable selectivity******Ongoing work in my group has concentrated on steps that could lead to for chemical analysis including (a) novel methods of filtration of particles from droplets, (b) the automated detection of droplet composition based on electrochemical properties and (c) bridging these samples to an electrospray. By bridging this to an Ion Mobility Spectrometer (IMS), a sensor that tracks ion mobility within an electric field, improved sensing capability is possible. Using valving and capillary loading methods developed as part of other work I have led, it is possible to perform many sample preparation and chemical analysis steps on the DMF platform and load an electrospray. Successful implementation requires an improved grasp of the electrospray used to ionize the sample and high resolution over short distances. This would focus on controlling pulsing behavior of the electrospray and electronics-independent timing of the sample ejection for improved drift-time measurement.

数字微流体(DMF)能够控制和操作从皮升到微升的微小和离散的液体单位，并为患者提供快速个性化诊断的长期潜力，例如，跟踪肥胖治疗的效果。在典型的封闭配置中，液滴被限制在两个平行的衬底之间。限定电极栅格的底部衬底和用作电接地的顶部电极。通过在电极之间施加电场，可以协调和操纵液滴，例如使其合并、分裂或突出成更小的液滴。由于离散的操作程序，通常与生化方案和分析相关的液体控制和处理可以由数字微流控设备完全模拟。液滴可以作为孤立的运输胶囊使用，同时也可以作为发生化学反应的微反应器。流体体积可以大大减少，扩散和反应速度会增加。通过这种方式，DMF设备利用了在微观上占主导地位的现象，而不是像许多连续流动设备那样对它们不利。常见的检测方法，如光学检测，已经变得更难与微型设备集成，特别是由于需要便携式的护理点应用。虽然与流体控制和处理相关的部件的尺寸已经大大减小，但用于化学反应检测的外部光学仪器的类似缩小规模更加困难。对于DMF装置来说，电化学检测是一种非常实用的技术。由于简单的传感器设计与微制造技术兼容，它可以集成在一起。此外，电化学换能器可以与廉价的仪器相结合，并且具有低功耗、高灵敏度、低检测限和可调的选择性*我的团队目前的工作集中在可能导致化学分析的步骤上，包括(A)过滤液滴中颗粒的新方法，(B)基于电化学特性的液滴成分自动检测，以及(C)将这些样品连接到电喷雾。通过将其连接到离子迁移率光谱仪(IMS)，这是一种跟踪电场中离子迁移率的传感器，可以提高传感能力。使用作为我领导的其他工作的一部分开发的阀门和毛细管上载法，可以在DMF平台上执行许多样品准备和化学分析步骤，并加载电喷雾。成功的实施需要更好地掌握用于电离样品的电喷雾，并在短距离内保持高分辨率。这将侧重于控制电喷雾的脉冲行为和样品喷射的电子独立计时，以改进漂移时间测量。