Del Moral-Zamora Beatriz, Punter-Villagrassa Jaime, Oliva-Brañas Ana M, Álvarez-Azpeitia Juan Manuel, Colomer-Farrarons Jordi, Samitier Josep, Homs-Corbera Antoni, Miribel-Català Pere Ll
Department of Electronics, University of Barcelona, Barcelona, Spain.
Nanobioengineering Group, Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain.
Electrophoresis. 2015 May;36(9-10):1130-41. doi: 10.1002/elps.201400446. Epub 2015 Apr 27.
The present paper reports a bacteria autonomous controlled concentrator prototype with a user-friendly interface for bench-top applications. It is based on a microfluidic lab-on-a-chip and its associated custom instrumentation, which consists of a dielectrophoretic actuator, to preconcentrate the sample, and an impedance analyzer, to measure concentrated bacteria levels. The system is composed of a single microfluidic chamber with interdigitated electrodes and an instrumentation with custom electronics. The prototype is supported by a real-time platform connected to a remote computer, which automatically controls the system and displays impedance data used to monitor the status of bacteria accumulation on-chip. The system automates the whole concentrating operation. Performance has been studied for controlled volumes of Escherichia coli samples injected into the microfluidic chip at constant flow rate of 10 μL/min. A media conductivity correcting protocol has been developed, as the preliminary results showed distortion of the impedance analyzer measurement produced by bacterial media conductivity variations through time. With the correcting protocol, the measured impedance values were related to the quantity of bacteria concentrated with a correlation of 0.988 and a coefficient of variation of 3.1%. Feasibility of E. coli on-chip automated concentration, using the miniaturized system, has been demonstrated. Furthermore, the impedance monitoring protocol had been adjusted and optimized, to handle changes in the electrical properties of the bacteria media over time.
本文报道了一种用于台式应用的具有用户友好界面的细菌自主控制浓缩器原型。它基于微流控芯片实验室及其相关的定制仪器，该仪器由用于预浓缩样品的介电泳致动器和用于测量浓缩细菌水平的阻抗分析仪组成。该系统由一个带有叉指电极的单个微流控腔室和一个带有定制电子设备的仪器组成。该原型由连接到远程计算机的实时平台支持，该平台自动控制系统并显示用于监测芯片上细菌积累状态的阻抗数据。该系统使整个浓缩操作自动化。已经研究了以10 μL/min的恒定流速注入微流控芯片的受控体积的大肠杆菌样品的性能。由于初步结果表明细菌培养基电导率随时间变化会导致阻抗分析仪测量失真，因此开发了一种培养基电导率校正协议。通过校正协议，测量的阻抗值与浓缩细菌的数量相关，相关性为0.988，变异系数为3.1%。已经证明了使用小型化系统在芯片上自动浓缩大肠杆菌的可行性。此外，已经调整和优化了阻抗监测协议，以处理细菌培养基电性能随时间的变化。
