Microfabrication for Biomedical Research

人们对同时检测单个生物样品中的许多不同蛋白质有强烈的兴趣。 对所收集样品的大小的限制要求这些测量在尽可能小的流体体积上进行。 这种兴趣一直是生物医学应用的微流体装置的发展背后的驱动力之一。 转向这些较小规模的系统有许多优点。 首先，它们能够分析较小的样品体积。 其次，在毛细管电泳等应用中，微流控系统可以在比大规模系统少得多的时间内实现相同的分离分辨率。 最后，分析装置的尺寸减小提高了开发便携式分析设备的可能性。 正在开发的一种设备能够同时测量8个不同的电泳运行，而另一种设备，多通道流动免疫测定，旨在测量单个样品中多达20种不同的分析物。 后一种设备在监测新生儿的免疫或激素状态或测量单个患者样本中的不同细胞通路方面具有很大的潜力。 我们小组的其他兴趣包括设计和开发能够分析单细胞分泌和生理的设备。 我们的设施现在已经发展到一个地步，我们能够就如何生产满足他们特定需求的微流体设备与研究人员进行建议和合作。 LBPS与NIST的科学家合作开发了一种用于免疫测定的微流体设备，可以同时分离和检测多种蛋白质，最终可用于各种临床和研究应用。 使用NIST的微加工设施，我们能够制造具有任何所需二维配置的微米级玻璃封装微流体系统。 与现有的阵列技术相比，通道器件架构具有几个优点;例如，通过单点捕获检测蛋白质，并且可以使用小得多的样品体积。 在与NIST的第二次合作中，LBPS开发了一种用于DNA片段电泳分离的八通道塑料设备。 目前，我们的重点是进一步开发这种芯片的蛋白质组学应用。 一个重要的挑战，这些设备的成功实施的关键，是实现高灵敏度的荧光标记的实时检测的能力。 我们已经实现了10 pM，10 Hz的标签检测在8个独立的50 u通道在塑料基板上使用一种新的球透镜，光纤的方法，耦合到一个成像光谱仪与CCD检测，允许四个标记染料被同时使用。

There is a strong interest in the simultaneous detection of a number of different proteins in a single biological sample. Limitations on the size of the collected sample require that these measurements be done on as small a volume of fluid as possible. This interest has been one of the driving forces behind the development of microfluidic devices for biomedical applications. The move to these smaller-scale systems has a number of advantages. First, they are capable of analyzing smaller sample volumes. Second, in applications such as capillary electrophoresis the microfluidic system can achieve the same separation resolution in much less time than a larger-scale system. Finally, the reduced size of the analysis setup raises the possibility of developing portable analytical devices. One device under development is capable of measuring eight different electrophoretic runs simultaneously, while another device, a multi-channel flow immunoassay, is intended to measure up to twenty different analytes in a single sample. This latter device holds great potential for monitoring the immune or hormonal status of new born infants or measuring different cellular pathways within a single patient sample. Other interests of our group include the design and development of devices capable of analyzing the secretions and physiology of single cells. Our facilities have now developed to a point where we are able to advise and collaborate with investigators on how to produce microfluidic devices that address their specific needs. In collaboration with scientists at NIST, LBPS has developed a microfluidic device for immunoassay that can simultaneously isolate and detect multiple proteins, and which can ultimately be used for a variety of clinical and research applications. Using the microfabrication facilities at NIST, we are able to make micrometer-scale glass-encapsulated microfluidic systems with any desired two-dimensional configuration. The channel device architecture has several advantages over existing array technology; for example, proteins are detected by single-point capture, and much smaller sample volumes can be used. In a second collaboration with NIST, LBPS developed an eight channel plastic device for electrophoretic separation of DNA fragments. Currently, our focus is to further develop this chip for proteomic applications. One important challenge, key to the successful implementation of these devices, is the ability to achieve real-time detection of fluorescent labels at high sensitivity. We have achieved 10pM, 10 Hz label detection in eight independent 50u channels in a plastic substrate using a novel ball-lens, fiber optic approach that couples to an imaging spectrograph with CCD detection that allows four labeling dyes to be used simultaneously.