Jung Jae Hee, Lee Jung Eun
Department of Electrical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Center for Environment, Health, and Welfare Research, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea.
Sci Rep. 2016 Feb 23;6:21473. doi: 10.1038/srep21473.
Observing microbial colonies is the standard method for determining the microbe titer and investigating the behaviors of microbes. Here, we report an automated, real-time bacterial microcolony-counting system implemented on a wide field-of-view (FOV), on-chip microscopy platform, termed ePetri. Using sub-pixel sweeping microscopy (SPSM) with a super-resolution algorithm, this system offers the ability to dynamically track individual bacterial microcolonies over a wide FOV of 5.7 mm × 4.3 mm without requiring a moving stage or lens. As a demonstration, we obtained high-resolution time-series images of S. epidermidis at 20-min intervals. We implemented an image-processing algorithm to analyze the spatiotemporal distribution of microcolonies, the development of which could be observed from a single bacterial cell. Test bacterial colonies with a minimum diameter of 20 μm could be enumerated within 6 h. We showed that our approach not only provides results that are comparable to conventional colony-counting assays but also can be used to monitor the dynamics of colony formation and growth. This microcolony-counting system using on-chip microscopy represents a new platform that substantially reduces the detection time for bacterial colony counting. It uses chip-scale image acquisition and is a simple and compact solution for the automation of colony-counting assays and microbe behavior analysis with applications in antibacterial drug discovery.
观察微生物菌落是确定微生物滴度和研究微生物行为的标准方法。在此，我们报告了一种在宽视场（FOV）片上显微镜平台（称为ePetri）上实现的自动化实时细菌微菌落计数系统。该系统采用具有超分辨率算法的亚像素扫描显微镜（SPSM），能够在5.7 mm×4.3 mm的宽视场内动态跟踪单个细菌微菌落，无需移动载物台或镜头。作为演示，我们每隔20分钟获取一次表皮葡萄球菌的高分辨率时间序列图像。我们实施了一种图像处理算法来分析微菌落的时空分布，其发展过程可从单个细菌细胞开始观察。最小直径为20μm的测试细菌菌落可在6小时内计数。我们表明，我们的方法不仅能提供与传统菌落计数测定相当的结果，还可用于监测菌落形成和生长的动态过程。这种使用片上显微镜的微菌落计数系统代表了一个新平台，大幅缩短了细菌菌落计数的检测时间。它采用芯片级图像采集，是用于菌落计数测定自动化和微生物行为分析的简单紧凑解决方案，可应用于抗菌药物发现领域。
