Sabounchi Poorya, Morales Alfredo M, Ponce Pierre, Lee Luke P, Simmons Blake A, Davalos Rafael V
Energy Systems Department, Sandia National Laboratories, Livermore, CA, USA.
Biomed Microdevices. 2008 Oct;10(5):661-70. doi: 10.1007/s10544-008-9177-4.
We present an on-chip microfluidic sample concentrator and detection triggering system for microparticles based on a combination of insulator-based dielectrophoresis (iDEP) and electrical impedance measurement. This platform operates by first using iDEP to selectively concentrate microparticles of interest based on their electrical and physiological characteristics in a primary fluidic channel; the concentrated microparticles are then directed into a side channel configured for particle detection using electrical impedance measurements with embedded electrodes. This is the first study showing iDEP concentration with subsequent sample diversion down an analysis channel and is the first to demonstrate iDEP in the presence of pressure driven flow. Experimental results demonstrating the capabilities of this platform were obtained using polystyrene microspheres and Bacillus subtilis spores. The feasibility of selective iDEP trapping and impedance detection of these particles was demonstrated. The system is intended for use as a front-end unit that can be easily paired with multiple biodetection/bioidentification systems. This platform is envisioned to act as a decision-making component to determine if confirmatory downstream identification assays are required. Without a front end component that triggers downstream analysis only when necessary, bio-identification systems (based on current analytical technologies such as PCR and immunoassays) may incur prohibitively high costs to operate due to continuous consumption of expensive reagents.
我们展示了一种基于绝缘介质电泳（iDEP）和电阻抗测量相结合的用于微粒的片上微流控样品浓缩器和检测触发系统。该平台的工作方式是，首先利用iDEP根据目标微粒在主流体通道中的电学和生理特性对其进行选择性浓缩；然后将浓缩后的微粒导入一个侧通道，该侧通道配置有使用嵌入式电极进行电阻抗测量的粒子检测装置。这是第一项展示iDEP浓缩并随后将样品转移至分析通道的研究，也是第一项在压力驱动流存在的情况下展示iDEP的研究。使用聚苯乙烯微球和枯草芽孢杆菌孢子获得了证明该平台功能的实验结果。证明了对这些粒子进行选择性iDEP捕获和阻抗检测的可行性。该系统旨在用作前端单元，可轻松与多种生物检测/生物识别系统配对。该平台被设想为一个决策组件，用于确定是否需要进行下游确认性鉴定分析。如果没有仅在必要时触发下游分析的前端组件，生物识别系统（基于当前的分析技术，如PCR和免疫分析）可能会因持续消耗昂贵试剂而导致运行成本过高。
