HSG-IMIT, Wilhelm-Schickard-Strasse 10, 78052, Villingen-Schwenningen, Germany.
Lab Chip. 2010 Dec 7;10(23):3284-90. doi: 10.1039/c0lc00129e. Epub 2010 Oct 11.
This paper reports a novel microfluidic-chip based platform using "phase-transfer magnetophoresis" enabling continuous biomolecule processing. As an example we demonstrate for the first time continuous DNA extraction from cell lysate on a microfluidic chip. After mixing bacterial Escherichia coli culture with superparamagnetic bead suspension, lysis and binding buffers, DNA is released from cells and captured by the beads. These DNA carrying beads are continuously transported across the interfaces between co-flowing laminar streams of sample mixture, washing and elution buffer. Bead actuation is achieved by applying a time-varying magnetic field generated by a rotating permanent magnet. Flagella-like chains of magnetic beads are formed and transported along the microfluidic channels by an interplay of fluid drag and periodic magnetic entrapment. The turnover time for DNA extraction was approximately 2 minutes with a sample flow rate of 0.75 µl s(-1) and an eluate flow rate of 0.35 µl s(-1). DNA recovery was 147% (on average) compared to bead based batch-wise extraction in reference tubes within a dilution series experiment over 7 orders of magnitude. The novel platform is suggested for automation of various magnetic bead based applications that require continuous sample processing, e.g. continuous DNA extraction for flow-through PCR, capture and analysis of cells and continuous immunoassays. Potential applications are seen in the field of biological safety monitoring, bioprocess control, environmental monitoring, or epidemiological studies such as monitoring the load of antibiotic resistant bacteria in waste water from hospitals.
本文报道了一种新颖的基于微流控芯片的平台，该平台采用“相转移磁泳”技术，能够实现连续的生物分子处理。作为一个例子，我们首次在微流控芯片上实现了从细胞裂解物中连续提取 DNA。将细菌大肠杆菌培养物与超顺磁珠悬浮液、裂解和结合缓冲液混合后，DNA 从细胞中释放出来并被珠体捕获。这些携带 DNA 的珠体被连续地输送到样品混合物的层流之间的界面，流经洗涤和洗脱缓冲液。珠体的驱动是通过施加由旋转永磁体产生的时变磁场来实现的。磁珠的鞭毛状链通过流体阻力和周期性磁捕获的相互作用形成并沿着微流道输送。在样品流速为 0.75µl s(-1)、洗脱液流速为 0.35µl s(-1)的情况下，DNA 提取的周转时间约为 2 分钟。与参考管中基于珠粒的分批提取相比，在稀释系列实验中，DNA 回收率平均为 147%（超过 7 个数量级）。该新型平台建议用于自动化各种基于磁珠的应用，这些应用需要连续的样品处理，例如用于流动式 PCR 的连续 DNA 提取、细胞的捕获和分析以及连续免疫测定。潜在的应用领域包括生物安全监测、生物过程控制、环境监测或流行病学研究，例如监测医院废水抗生素耐药菌的负荷。
