Thompson Jason A, Du Xiaoguang, Grogan Joseph M, Schrlau Michael G, Bau Haim H
Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104, USA.
Current Address: Research Center for Analytical Sciences, Northeastern University, Shenyang, China.
J Micromech Microeng. 2010 Nov;20(11). doi: 10.1088/0960-1317/20/11/115017. Epub 2010 Oct 15.
Microbeads offer a convenient and efficient means to immobilize biomolecules and capture target molecules of interest in microfluidic immunoassay devices. In this study, hot embossing is used to form wells enabling the direct incorporation of a microbead array in a plastic substrate. We demonstrate two techniques to populate the well array with beads. In the first case, encoded beads with various functionalizations are distributed randomly among the wells and their position registered by reading their encoding. Alternatively, beads are controllably placed at predetermined positions and decoding is not required. The random placement technique is demonstrated with two functionalized bead types that are distributed among the wells and then decoded to register their locations. The alternative, deliberate placement technique is demonstrated by controllably placing magnetic beads at selected locations in the array using a magnetic probe. As a proof of concept to illustrate the biosensing capability of the randomly assembled array, an on-chip, bead-based immunoassay is employed to detect the inflammatory protein Interleukin-8. The principle of the assay, however, can be extended to detect multiple targets simultaneously. Our method eliminates the need to interface silicon components with plastic devices to form microarrays containing individually addressable beads. This has the potential to reduce the cost and complexity of lab-on-chip devices for medical diagnosis, food and water quality inspection, and environmental monitoring.
微珠为在微流控免疫分析装置中固定生物分子和捕获目标感兴趣分子提供了一种方便且高效的手段。在本研究中，热压印用于形成孔，从而能够将微珠阵列直接整合到塑料基板中。我们展示了两种用珠子填充孔阵列的技术。在第一种情况下，具有各种功能化的编码珠子随机分布在孔中，并通过读取其编码来记录它们的位置。或者，珠子被可控地放置在预定位置，无需解码。随机放置技术通过两种功能化珠子类型进行展示，它们分布在孔中，然后进行解码以记录其位置。另一种有意放置技术通过使用磁探针将磁珠可控地放置在阵列中的选定位置来展示。作为说明随机组装阵列生物传感能力的概念验证，采用基于芯片的珠基免疫分析来检测炎症蛋白白细胞介素 - 8。然而，该分析原理可扩展到同时检测多个目标。我们的方法无需将硅组件与塑料装置连接以形成包含可单独寻址珠子的微阵列。这有可能降低用于医学诊断、食品和水质检测以及环境监测的芯片实验室装置的成本和复杂性。
