Microfabrication for Biomedical Research

生物医学研究的微加工

• 批准号: 6836995
• 负责人: Paul D Smith
• 金额: --
• 依托单位: OFFICE OF THE DIRECTOR, NATIONAL INSTITUTES OF HEALTH
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6836995
• 关键词: binding proteins; bioengineering /biomedical engineering; biomedical equipment development; biopsy; capillary electrophoresis; cell sorting; cervical /vaginal smear; cervix neoplasms; high throughput technology; human papillomavirus; immunoelectrophoresis; immunofluorescence technique; microcapsule; miniature biomedical equipment; molecular oncology; molecular pathology; nanotechnology; portable biomedical equipment; sample collection

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 volumes of sample. 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. In collaboration with scientists at NIST, DBEPS is developing a microfluidic device for immunoaffinity electrophoresis, in which multiple proteins will be simultaneously isolated and detected. Using the microfabrication facilities at NIST, we are able to make micrometer-scale glass-encapsulated microfluidic systems with any desired two-dimensional configuration. The prototype devices consist of a long glass-encapsulated channel, 50mm x 15 mm x 30cm, with a serpentine pattern. Side ports are used for pressure-driven loading of different biotinylated antibodies into each segment of the channel; these antibodies bind to streptavidin that has been covalently linked to the channel walls. After the antibodies have been immobilized, the sample under analysis flows through the entire device. Electrical control of the sample flow permits adjustment of the residence time in each segment in order to optimize binding. Initially, the captured proteins will be detected optically, using fluorescent tags. After detection, the captured proteins may be eluted from the channel for further analysis. The channel device architecture has several advantages over existing array technology: the proteins are detected by single-point capture, and much smaller sample volumes can be used. In addition, we hope to be able to reuse the channels with the bound antibodies for multiple samples. The immediate clinical need that motivates this project is an epidemiological study of the immune response to Human Papillomavirus (HPV) infection, and the relationship between this response and the development of cervical cancer. Studies of lymphocytes taken from peripheral blood samples have suggested a difference between patients whose cells respond to HPV peptides with a T lymphocyte helper cell type 1 response (Th1-type response) compared to those with a Th-2 type response. In order to better understand these differences at a molecular level, it is necessary to detect and quantify a number of selected immune regulatory molecules directly in cervical secretions, as a local probe, rather than blood samples as a systemic probe of the immune response. From these requirements, the need for a microfluidic device such as the one being developed becomes clear. The volume of cervical secretions that can be collected is quite small, typically 25-50 microliters, and the difficulty in collecting a sufficient number of fluid samples for an epidemiological study makes it imperative to extract as much information as possible from a single sample Conventional diagnostic techniques, such as ELISA, only allow for the analysis of one or two analytes from a sample of this size. The proposed device will be able to detect over a dozen proteins from a one-microliter sample volume. Although the functionality of the proposed device is being targeted for this particular application, there is every reason to expect that, once this device is realized, many other biological and clinical applications could also be addressed.

人们对在单个生物样品中同时检测多种不同蛋白质有着浓厚的兴趣。由于所收集样品尺寸的限制，这些测量必须在尽可能小的液体体积上进行。这种兴趣一直是生物医学应用微流体装置发展背后的驱动力之一。转向这些规模较小的系统有许多优点。首先，它们能够分析较小体积的样品。其次，在毛细管电泳等应用中，微流控系统可以在比大型系统更短的时间内实现相同的分离分辨率。最后，分析装置尺寸的减小提高了开发便携式分析设备的可能性。