Collection, focusing, and metering of biomolecules using addressable microelectrode arrays for portable low-power bioanalysis

摘要：微流控技术的进步使得越来越复杂的生物传感和生物分析操作能够在微尺度上进行，其中许多应用使用了如此少量的DNA，因此必须首先将其预浓缩到可检测的水平。通常，样本包含多个成分或未知，因此很难使用聚合酶链式反应(PCR)扩增等技术来提高浓度水平。精确处理微通道几何形状中的微量生物分子的有效策略是迫切需要的，然而事实证明，利用电流产生技术实现同时浓缩、聚焦和计量是具有挑战性的。这项研究计划将通过探索先进的微流控系统来解决这些问题，该系统结合了片上电极阵列，以精确和可控的增量对DNA和其他带电生物分子进行数字采集和测量。这项技术在施加小电位(~1V)时在活性电极之间传输带电的生物分子，并且能够在适合于便携式操作的小设备占用空间内实现数量级的浓度增加(单个AA电池可以提供足够的功率来执行多次浓缩和计量操作)。采集的样品高度集中，样品区域的大小和形状完全由电极几何形状决定。这些基础研究的结果还将被应用于探索这项技术的全新应用，包括(I)将捕获过程与叠加的流体动力流相结合，以便在适合后续反应或分析的新缓冲环境中浓缩并重新悬浮DNA样本；(Ii)利用电极捕获过程收集自由溶液中的DNA，然后直接在收集的DNA上注入凝胶筛分基质以执行后续的电泳分离；以及(Iii)捕获和聚焦蛋白质样本。这些新颖的应用将解决开发先进的基于DNA的分析技术的引人注目的经济激励因素，这些技术将成为下一代基因组分析系统的关键组件。除了使基因组分析技术变得更负担得起所带来的商业影响外，这项技术还将通过与PI努力相结合，极大地促进化学工程学科新兴多学科领域的教育，为本科生在物理、化学和生命科学之间的接口开发新的教育体验。PI还将推出一系列定期辩论，涉及本科生、研究生和教职员工，以激发人们对生物和纳米技术问题的社会影响的兴趣，同时提高沟通技能，并提供可供整个系共享的共同经验。参与这个项目的学生将获得化学工程学科前沿领域的实践经验，社会将通过开发新的基因组分析技术来改善医疗保健。

Abstract: Advances in microfluidic technology have enabled increasingly sophisticated biosensing and bioassay operations to be conducted at the microscale, many of these applications employ such small amounts of DNA that it must first be pre-concentrated to a detectable level. Often the sample contains multiple components or is unknown, making it difficult to employ techniques like polymerase chain reaction (PCR) amplification to increase the concentration level. Efficient strategies for precisely handling minute quantities of biomolecules in microchannel geometries are critically needed, however it has proven challenging to achieve simultaneous concentration, focusing, and metering with current-generation technology. This research program will address these issues by exploring advanced microfluidic systems incorporating arrays of on-chip electrodes to digitally collect and meter DNA and other charged biomolecules in precise and controllable increments. This technique transports charged biomolecules between active electrodes upon application of a small potential (~1 V), and is capable of achieving orders of magnitude concentration increases within a small device footprint suitable for portable operation (a single AA battery may deliver sufficient power to perform multiple concentration and metering operations). The collected samples are highly focused, with sample zone size and shape defined solely by electrode geometry. The results of these fundamental studies will also be applied to explore entirely new first-of-their-kind applications for this technology including (i) coupling the capture process with a superimposed hydrodynamic flow to concentrate and re-suspend a DNA sample in a new buffer environment suitable for subsequent reactions or analysis, (ii) harnessing the electrode capture process to collect DNA in free solution followed by hydrodynamic injection of a gel sieving matrix directly over the collected DNA to perform subsequent electrophoretic separation, and (iii) capture and focusing of protein samples. These novel applications will address the compelling economic incentives for developing advanced DNA-based assay technologies that will be key components in next-generation genomic analysis systems. In addition to the commercial impact associated with making genomic analysis technology more affordable, this technology will greatly enhance education in emerging multidisciplinary areas of the Chemical Engineering discipline through integration with the PIs efforts to develop new educational experiences for undergraduates at the interface between the physical, chemical, and life sciences. The PI will also introduce a regular series of debates involving undergraduates, graduate students, and faculty to stimulate interest in the societal impact of bio- and nanotechnology issues while improving communication skills and providing a common experience that can be shared by the entire department. Students involved in this project will gain hands-on experience in areas at the frontiers of the Chemical Engineering discipline, and society will benefit through the development of new genomic analysis technology for improved health care.