Faculty of Science and Engineering, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, UK.
Department of Chemistry, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
Lab Chip. 2016 May 24;16(11):2108-15. doi: 10.1039/c6lc00228e.
Despite recent advances in microfluidic-based integrated diagnostic systems, the sample introduction interface, especially with regards to large volume samples, has often been neglected. We present a sample introduction interface that allows direct on-chip processing of crude stool samples for the detection of Helicobacter pylori (H. pylori). The principle of IFAST (immiscible filtration assisted by surface tension) was adapted to include a large volume sample chamber with a septum-based interface for stool sample introduction. Solid chaotropic salt and dry superparamagnetic particles (PMPs) could be stored on-chip and reconstituted upon sample addition, simplifying the process of release of DNA from H. pylori cells and its binding to the PMPs. Finally, the PMPs were pulled via a magnet through a washing chamber containing an immiscible oil solution and into an elution chamber where the DNA was released into aqueous media for subsequent analysis. The entire process required only 7 min while enabling a 40-fold reduction in working volume from crude biological samples. The combination of a real-world interface and rapid DNA extraction offers the potential for the methodology to be used in point-of-care (POC) devices.
尽管基于微流控的集成诊断系统最近取得了进展，但样品引入界面，特别是对于大容量样品，通常被忽视。我们提出了一种样品引入界面，允许直接在芯片上处理粗粪便样品，用于检测幽门螺杆菌（H. pylori）。IFAST（表面张力辅助的不混溶过滤）的原理被改编为包括一个带有基于隔膜的接口的大容量样品室，用于粪便样品的引入。固态变性盐和干燥超顺磁颗粒（PMPs）可以储存在芯片上，并在样品添加时重新配制，简化了从 H. pylori 细胞中释放 DNA 及其与 PMPs 结合的过程。最后，通过磁铁将 PMPs 穿过含有不混溶油溶液的洗涤室，并进入洗脱室，在洗脱室中将 DNA 释放到水性介质中进行后续分析。整个过程仅需 7 分钟，同时使从粗生物样品中减少工作体积达到 40 倍。实际接口和快速 DNA 提取的结合为该方法在即时护理（POC）设备中的应用提供了潜力。
