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

摘要：微流体技术的进步使得越来越复杂的生物传感和生物测定操作能够在微尺度上进行，许多这些应用使用如此少量的DNA，以至于必须首先将其预浓缩到可检测的水平。通常样品含有多种成分或未知成分，因此很难采用聚合酶链反应（PCR）扩增等技术来提高浓度水平。在微通道几何形状中精确处理微量生物分子的有效策略是迫切需要的，然而，使用当前一代技术实现同时集中，聚焦和计量已被证明具有挑战性。该研究计划将通过探索先进的微流体系统来解决这些问题，该系统包含芯片上电极阵列，以精确可控的增量数字收集和测量DNA和其他带电生物分子。该技术通过施加小电位（~1 V）在活性电极之间传输带电生物分子，并且能够在适合便携式操作的小设备占地面积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度和计量操作）。收集的样品高度聚焦，样品区大小和形状仅由电极几何形状定义。这些基础研究的结果也将应用于探索该技术的全新的首次应用，包括(i)将捕获过程与叠加的流体动力学流动耦合，将DNA样本浓缩并重新悬浮在适合后续反应或分析的新缓冲环境中；（ii）利用电极捕获过程在自由溶液中收集DNA，然后在收集的DNA上直接注射凝胶筛分基质进行后续的电泳分离，以及（iii）捕获和聚焦蛋白质样品。这些新颖的应用将解决开发先进的基于dna的分析技术的令人信服的经济激励，这些技术将成为下一代基因组分析系统的关键组成部分。除了与使基因组分析技术更便宜相关的商业影响外，该技术还将通过与pi的努力整合，在物理、化学和生命科学的界面上为本科生开发新的教育体验，从而极大地加强化学工程学科新兴多学科领域的教育。PI还将引入一系列由本科生、研究生和教师参与的定期辩论，以激发对生物和纳米技术问题的社会影响的兴趣，同时提高沟通技巧，并提供可由整个系共享的共同经验。参与该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.