XYZ on a Chip: Integrated Biochip Microfluidics Using Supported Lipid Bilayers

该工程微系统公司的目标：“XYZ”on a Chip项目计划开发一系列小型化的生物分析处理模块，这些模块将被集成到玻璃基板上的“生物芯片”中；该生物芯片将能够对纳升或皮升范围内的流体进行精细操作，并在蛋白质组学、药品的表征和筛选以及蛋白质的选择和纯化方面具有潜在的应用。拟议的研究的新方面涉及将水凝胶致动器用于微阀和蠕动微泵，以及微通道壁或具有系留磷脂双层的高比表面积色谱填料的功能化。这种表面修饰提供了结合膜完整或膜相关的功能单元的可能性，如受体、酶和离子载体，以允许监测反应产物，并通过分子模板实现蛋白质分离。首先，PI将开发使能技术，将水凝胶对外部刺激(如温度、电场或pH)的响应的理解扩展到水凝胶在尺寸上显著减小且通过共价附着在表面上的机械约束的情况。此外，他们还将开发程序，以促进和验证约束几何形状的直线微通道中的系留膜组件的自组织以及在色谱填料上的自组织。虽然自由悬浮在固体基质上的磷脂双层膜的结构和动力学已经得到了相当广泛的研究，但更具机械稳定性的系留膜直到最近才被探索。第二个主题涉及开发一系列生物处理模块，这些模块将是最终创造一个完整的“芯片实验室”所必需的。根据功能定义，待开发的各个模块类别如下：微流体流量控制：热敏和电敏水凝胶将用作微阀的致动器，并在弹性阻挡膜的帮助下用于蠕动微泵。在更复杂的体系中，共价结合到水凝胶致动器表面和相邻通道表面的磷脂双层膜将作为扩散屏障，从而促进直接泵送和计量输送。微反应器：连接在圆柱形微通道内表面或填充床中颗粒表面的磷脂双层膜将用于支持整膜或相关膜蛋白质，如受体、酶和离子载体。这些双层功能化管式和填充床反应器将在连续流动条件下进行研究。分离设备：直线微通道将用系留膜功能化，并评估膜结合蛋白的电泳分离效率。在另一种方法中，他们将双层膜系在高表面积的柱填料载体上，以创建固定的脂膜色谱相。这两种类型的底物都将被用于基于相转移层析的蛋白质选择。不同模块的检测方案将基于光学(表面等离子体或波导光谱)、共聚焦显微镜和吸收/荧光光谱方法。第三个主题将涉及将这些功能模块集成到生物分析设备中，这些功能模块构成了一个微观的“工具包”，能够结合包括样品引入、灌流、反应、分离和分析在内的过程操作。发展工作将按照日益复杂的顺序进行协调和安排。每种使能技术(响应性水凝胶、功能性系留双层、衍生填充床)的微缩放，以及酌情开发更简单的模块，将同时进行。这将允许开发两种或两种以上技术重叠的更复杂的模块。

9980799FrankThe goal of this Engineering Microsystems: "XYZ" on a Chip project proposes to develop a series of miniaturized, bioanalytical process modules that will be integrated into a "biochip" on a glass substrate; the biochip will be capable of exquisite manipulation of fluids in the nanoliter or picoliter range and have potential applications in proteomics, characterization and screening of pharmaceuticals, and protein selection and purification. Novel aspects of the proposed research involve the use of hydrogel actuators for microvalves and peristaltic micropumps and the functionalization of microchannel walls or high surface-area chromatographic packing material with tethered phospholipid bilayers. This surface modification offers the possibility of incorporating membrane-integral or membrane-associated functional units such as receptors, enzymes, and ionophores to allow monitoring of reaction products and to achieve protein separations through molecular templating.The proposed research is divided into three themes. In the first, the PIs will develop the enabling technology that will extend the understanding of hydrogel response to external stimuli, such as temperature, electric field, or pH, to the case where the hydrogel is both dramatically reduced in dimension and mechanically constrained by covalent attachment to a surface. In addition, they will develop procedures for promoting and verifying the self-organization of the tethered membrane components in the constrained geometries of the straight microchannels and on chromatographic packing. While the structure and dynamics of phospholipid bilayers freely suspended on a solid substrate have been rather extensively studied, the more mechanically robust tethered membranes are only recently being explored. Moreover, the totally self-organized route to their formulation has barely been touched.The second theme involves the development of a series of bioprocess modules that will be necessary for the ultimate creation of a complete "lab-on-a-chip". The individual classes of modules to be developed, as defined by functionality, are as follows.Microfluidic Flow Control: Thermo- and electro-responsive hydrogels will be used as actuators in microvalves and, with the help of an elastomeric barrier membrane, peristaltic micropumps. In more complex systems, phospholipid bilayer membranes, covalently bound to the surface of the hydrogel actuators and adjacent channel surfaces, will serve as diffusion barriers, thus facilitating direct pumping and metered delivery.Microreactors: Phospholipid bilayer membranes, tethered on the inner surface of a cylindrical microchannel or on surfaces of particles in a packed bed, will be used to support integral-membrane or associated-membrane proteins such as receptors, enzymes, and ionophores. These bilayer-functionalized tubular and packed-bed reactors will be studied under continuous flow conditions.Separation Devices: Straight microchannels will be functionalized with tethered membranes and evaluated for electrophoretic separation efficiency of membrane-bound proteins. In an alternative approach, they will tether bilayer membranes to high-surface-area column packing supports to create a stationary lipid membrane chromatography phase. Both types of substrates will be explored for protein selection based on phase transition chromatography. Detection schemes for the different modules will be based on optical (surface plasmon or waveguide spectroscopic), confocal microscopic, and absorption/fluorescence spectroscopic methods.The third theme will involve the integration of these functional modules, which constitute a micro "tool kit", into a bioanalytical device capable of a combination of process operations including sample introduction, perfusion, reaction, separation, and analysis. Development efforts will be coordinated and staged in order of increasing complexity. Microscaling of each of the enabling technologies (responsive hydrogels, functional tethered bilayers, derivatized packed beds) and, where appropriate, development of the simpler modules, will occur in parallel. This will allow the development of the more complex modules in which two or more technologies overlap.