The increasing needs of point-of-care diagnostics, quarantine of epidemic pathogens, and prevention of terrorism's bio-attacks have promised the future of portable real-time quantitative polymerase chain reaction (qPCR) sensors. This work aims at developing a highly sensitive and low-cost light emitting diode (LED)-based epifluorescence sensor module for qPCR sensor development and relevant bioassay applications. Inspired by the light stop design and dark-field detection of microscopes, this paper first reports a compact confocal LED epifluorescence sensor using a light stop with an arc-shaped aperture for enhancing the flexibility of quick DNA and PCR detection. The sensor features the advantages of the dichroic mirror-free and confocal (shared-focus) characteristics, which benefits size reduction and minimal optics used. It also allows extension to integrate with in situ real-time PCR thermal cycling since the sample slide is placed apart from the epi-sensing module. The epifluorescence sensor can detect as low as sub-ng/μL standard DNA and 10¹ copies of Salmonella typhimurium InvA gene sequences (cloned in E. coli and after 30-cycle PCR) with SYBR^® Green I from non-purified culture samples, having highly sensitive and specific signal responses comparable with that of a commercial qPCR instrument.

即时诊断，对流行病原体进行隔离以及防止恐怖主义的生物攻击的需求不断增长，这预示了便携式实时定量聚合酶链反应（qPCR）传感器的未来。这项工作旨在开发用于qPCR传感器开发和相关生物测定应用的基于高灵敏度和低成本的发光二极管（LED）的落射荧光传感器模块。受到光阑设计和显微镜暗场检测的启发，本文首次报道了一种紧凑型共聚焦LED荧光传感器，该传感器使用具有弧形孔径的光阑来增强快速DNA和PCR检测的灵活性。该传感器具有无二向色镜和共焦（共享聚焦）特性的优点，这有利于减小尺寸并减少使用的光学元件。原位实时PCR热循环，因为样品载玻片与Epi传感模块分开放置。落射荧光传感器可检测低至子纳克/μL的标准DNA和10个¹的副本鼠伤寒沙门氏菌invA的基因序列（在克隆大肠杆菌和之后30个循环的PCR）用SYBR ^®绿色我从未纯化培养物样品，具有与商业qPCR仪器相当的高度灵敏和特异的信号响应。