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

9980799frank这个工程微系统的目标：“XYZ”芯片项目建议开发一系列小型化的生物分析过程模块，这些模块将集成到玻璃基板上的“生物芯片”中；该生物芯片将能够在纳升或皮升范围内精确操作流体，并在蛋白质组学、药物表征和筛选以及蛋白质选择和纯化方面具有潜在的应用前景。提出的研究的新方面包括将水凝胶致动器用于微阀和蠕动微泵，以及微通道壁或高表面积色谱填料的功能化与系结磷脂双层。这种表面修饰提供了结合膜整体或膜相关功能单元（如受体、酶和离子载体）的可能性，从而可以监测反应产物并通过分子模板实现蛋白质分离。拟进行的研究分为三个主题。首先，pi将开发使能技术，以扩展对水凝胶对外部刺激（如温度、电场或pH值）的响应的理解，从而使水凝胶的尺寸大大减小，并受到表面共价附着的机械约束。此外，他们将开发程序，以促进和验证系留膜组分在直线微通道和色谱包装的受限几何形状中的自组织。虽然自由悬浮在固体基质上的磷脂双分子层的结构和动力学已经得到了相当广泛的研究，但机械上更坚固的系留膜直到最近才被探索。此外，它们形成的完全自组织的路线几乎没有被触及。第二个主题涉及开发一系列生物过程模块，这些模块将是最终创建完整的“芯片实验室”所必需的。要开发的模块的各个类（按功能定义）如下。微流体流动控制：热响应和电响应水凝胶将被用作微阀的执行器，并在弹性屏障膜的帮助下，用于蠕动微泵。在更复杂的系统中，磷脂双层膜共价结合到水凝胶致动器的表面和邻近的通道表面，将作为扩散屏障，从而促进直接泵送和计量输送。微反应器：磷脂双层膜系在圆柱形微通道的内表面或填充床中的颗粒表面上，将用于支持整体膜或相关膜蛋白，如受体，酶和离子载体。这些双层功能化管状和填充床反应器将在连续流动条件下进行研究。分离装置：直微通道将与系留膜功能化，并评估膜结合蛋白的电泳分离效率。在另一种方法中，他们将把双层膜系在高表面积柱填料支架上，以形成固定的脂膜色谱相。这两种类型的底物将探索基于相变色谱的蛋白质选择。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。第三个主题将涉及这些功能模块的集成，它们构成了一个微型“工具包”，成为一个生物分析设备，能够组合过程操作，包括样品导入、灌注、反应、分离和分析。开发工作将按照增加复杂性的顺序进行协调和分级。每种使能技术（反应性水凝胶、功能系绳双层、衍生化填料床）的微尺度化，以及在适当的情况下，更简单模块的开发，将并行进行。这将允许开发两种或更多技术重叠的更复杂模块。

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.