MS2 device: smartphone-facilitated mobile nucleic acid analysis on microfluidic device

Mobile sensing based on the integration of microfluidic devices and smartphones, so-called MS2 technology, has enabled many applications over recent years and continues to stimulate growing interest in both research communities and industries. In particular, MS2 technology has been proven to be able to be applied to molecular diagnostic analysis and can be implemented for basic research and clinical testing. However, the currently reported MS2-based nucleic acid analysis system has limited use in practical applications, because it is not integrated with quantitative PCR, multiplex PCR, and isothermal amplification functions, and lacks temperature control, image acquisition and real-time processing units with excellent performance. To provide a more universal and powerful platform, we here developed a novel MS2 device by integrating a thermocycler, a multi fluorescence detection unit, a PCR chip, an isothermal chip, and a smartphone. The MS2 device was approximately 325 mm (L) × 200 mm (W) × 200 mm (H) in volume and only 5 kg in weight, and showed an average power consumption of about 38.4 W. The entire nucleic acid amplification and analysis could be controlled through a self-made smartphone App. The maximum heating and cooling rates were 5 °C s−1 and 4 °C s−1, respectively. The entire PCR could be completed within 65 min. The temperature uniformity was less than 0.1 °C. Besides, the temperature stability over time (30 min) was within ±0.04 °C. Four optical channels were integrated (FAM, HEX, TAMRA, and ROX) on the MS2 device. In particular, the PCR-based detection sensitivity reached 1 copy per μL, and the amplification efficiency was calculated to be 106.8%. Besides, the MS2 device also was compatible with multiplex PCR and isothermal amplification. In short, the MS2 device showed performance consistent with that of traditional commercial equipment. Thus, the MS2 device provides an easy and integrated experimental platform for molecular diagnostic-related research and potential medical diagnostic applications.

基于微流控器件（microfluidic devices）与智能手机集成的移动传感技术，即MS2技术（MS2 technology），近年来已催生诸多应用，并持续在科研与工业领域引发愈发浓厚的研究兴趣。尤为关键的是，MS2技术已被证实可应用于分子诊断分析，且可用于基础研究与临床检测。然而，当前已报道的基于MS2技术的核酸分析系统实际应用场景受限，原因在于其未集成定量PCR（quantitative PCR）、多重PCR（multiplex PCR）与恒温扩增（isothermal amplification）功能，且缺乏性能优异的温控、图像采集及实时处理单元。为构建一款更具通用性与实用性的科研平台，本研究开发了一款新型MS2装置，集成了热循环仪（thermocycler）、多通道荧光检测单元（multi fluorescence detection unit）、PCR芯片（PCR chip）、恒温芯片（isothermal chip）与智能手机。该装置外形尺寸约为325 mm（长）×200 mm（宽）×200 mm（高），整机重量仅5 kg，平均功耗约38.4 W。整套核酸扩增与分析流程可通过自研智能手机应用程序（smartphone App）操控。其最大升降温速率分别可达5 ℃·s⁻¹与4 ℃·s⁻¹。整套PCR反应可在65分钟内完成，温控均匀性优于0.1 ℃。此外，其30分钟内的温控时间稳定性误差不超过±0.04 ℃。该MS2装置集成了4个光学通道（FAM、HEX、TAMRA及ROX）。尤为突出的是，其基于PCR的检测灵敏度可达1拷贝/μL，扩增效率经计算为106.8%。此外，该装置还兼容多重PCR与恒温扩增反应。简言之，该MS2装置的性能可媲美传统商用设备。因此，本装置可为分子诊断相关研究以及潜在的医学诊断应用提供一款便捷集成化的实验平台。