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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=710213
• 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）可以控制和操纵从Picoliter到微级尺度的微小和离散单位的流体和离散单位，并为患者快速个性化诊断提供了长期潜力，例如跟踪肥胖治疗效果。 在典型的封闭配置中，液滴仅限于两个并行基板之间。定义电极网格的底部底物和最高电极以充当电气接地。通过在电极之间施加电场，可以策划和操纵液滴，例如将其合并，分裂或突出为较小的液滴。由于离散的操作程序，通常可以通过数字微流体设备完全模仿与生化方案和测定相关的液体控制和处理。液滴可用作分离的传输胶囊，同时用作微反应器，以进行化学反应。流体体积可以大大减少，扩散和反应速率增加。通过这种方式，DMF设备利用了在显微镜上占主导地位的现象，而不是像许多连续的流动设备那样对其进行对抗。常见的检测方法（例如光学检测）变得更难与微型版本集成在一起，尤其是由于需要便携式，即时保健应用程序。尽管与流体控制和处理有关的组件的大小已大大降低，但更困难的化学反应检测外部光学仪器的相似缩小缩小幅度更加困难。电化学检测是DMF设备的一种非常可行的技术。由于简单的传感器设计与微加工技术兼容，因此可以集成。此外，电化学传感器可以与廉价的仪器结合使用，并且具有低功耗，高灵敏度，低检测极限和可调节性的选择性 我小组中的正在进行的工作集中在可能导致化学分析的步骤上，包括（a）液滴过滤的新方法，（b）基于电化学性质的液滴组成的自动检测以及（c）将这些样品桥接到电喷雾中。通过将其桥接到离子迁移率光谱仪（IMS）中，该传感器可以跟踪电场中离子迁移率的传感器，可以提高感应能力。使用我领导的其他工作的一部分开发的阀门和毛细管载荷方法，可以在DMF平台上执行许多样品制备和化学分析步骤，并加载电喷雾。成功的实施需要改善用于在短距离内将样品和高分辨率的电喷雾掌握。这将着重于控制样品射血的电喷雾和电子独立的时机的脉冲行为，以改善漂移时间测量。