Wan Liang, Gao Jie, Chen Tianlan, Dong Cheng, Li Haoran, Wen Yan-Zi, Lun Zhao-Rong, Jia Yanwei, Mak Pui-In, Martins Rui P
State Key Laboratory of Analog and Mixed-Signal VLSI, University of Macau, Macao SAR, China.
Department of ECE, Faculty of Science and Technology, University of Macau, Macao SAR, China.
Biomed Microdevices. 2019 Jan 7;21(1):9. doi: 10.1007/s10544-018-0354-9.
A major goal in the development of point-of-care (POC) devices is to build them as portable to provide a rapid and effective determination for disease pathogens. In nucleic acid testing, an optical detection system used to monitor the product of nucleic acid amplification has always been a bulky accessory. In this work, we developed a handheld, automatic and detection system-free thermal digital microfluidic (DMF) device for DNA detection by loop-mediated isothermal amplification (LAMP). Droplet manipulation and real-time temperature control systems were integrated into a handheld device. The control software could be installed into any tablet and communicate with the device via Bluetooth. In the experimentation, we loaded 2-μl samples with an electrowetting force into sandwich-structured DMF chips, thereby considerably reducing reagent consumptions. After an on-chip LAMP reaction, we added a highly concentrated SYBR Green I droplet and mixed it with a reaction droplet to enable product detection with the naked eye. This step prevented aerosol contamination by avoiding the exposure of the reaction droplet to the air. Using a blood parasite Trypanosoma brucei as a model system, this system showed similar results as a commercial thermal cycler and could detect 40 copies per reaction of the DNA target. This low-cost, compact device removed the bulky optical system for DNA detection, thus enabling it to be well suited for POC testing.
即时检测（POC）设备开发的一个主要目标是使其便于携带，以便对疾病病原体进行快速有效的检测。在核酸检测中，用于监测核酸扩增产物的光学检测系统一直是一个体积庞大的附件。在这项工作中，我们开发了一种用于通过环介导等温扩增（LAMP）进行DNA检测的手持式、自动且无需检测系统的热数字微流控（DMF）设备。液滴操控和实时温度控制系统集成到了一个手持式设备中。控制软件可以安装到任何平板电脑上，并通过蓝牙与设备通信。在实验中，我们利用电润湿力将2微升样品加载到夹心结构的DMF芯片中，从而大幅减少试剂消耗。在芯片上进行LAMP反应后，我们加入高浓度的SYBR Green I液滴，并将其与反应液滴混合，以便用肉眼检测产物。这一步通过避免反应液滴暴露于空气中防止了气溶胶污染。以血液寄生虫布氏锥虫作为模型系统，该系统显示出与商用热循环仪相似的结果，并且每次反应能够检测到40个DNA靶标拷贝。这种低成本、紧凑的设备去除了用于DNA检测的庞大光学系统，因此非常适合即时检测。
