Diep Tai The, Bizley Samuel, Ray Partha Pratim, Edwards Alexander Daniel
Department of Pharmacy, Reading School of Pharmacy, University of Reading, UK.
Microbiology and Immunology Department Pasteur Institute in Ho Chi Minh City 167 Pasteur St. District 3, Ho Chi Minh City, Vietnam.
HardwareX. 2021 Oct 16;10:e00242. doi: 10.1016/j.ohx.2021.e00242. eCollection 2021 Oct.
Incubation at controlled temperature is a key step in culture based microbiological tests. Access to culture-based microbiological testing requires access to conventional incubators in a laboratory. Portable incubators allow microbiological testing in the field and in resource-limited settings, and can eliminate the challenge of sample transportation, minimising the chance of sample degradation. Recent studies have reported low-cost portable incubator designs suitable for field or off-grid use, but these either need an external power supply (e.g. mains AC or 12 V DC), or rely on passive heating without thermostatic control. Here we report that small inexpensive uninterruptable power supply (UPS) products manufactured for consumer electronics and powered by lithium-ion battery packs allowing thermostatic temperature control in small portable incubators that can maintain precise temperatures with or without external power. We present an open-source design for a Microbiological Mobile Incubator (MicroMI) in two sizes for field use. The MicroMI is built from simple and widely available components and is easy to set up. The open source design can be customised for different numbers of samples. The smallest and most efficient design uses a vacuum insulated food flask that allows longer operation with smaller, lower capacity UPS. The larger flight case design has space for more samples, but depletes the battery faster. The UPS maintains a typical microbiology incubation temperature for up to 24 h without external power- ideal for typical incubation needed for culture methods. The battery capacity, incubator design, and external ambient temperature all affected duration of operation without requiring external power. We validated the MicroMI by conducting classical microbiological tests using agar petri dishes, slant cultures and dip slides, and biochemical tests. We conclude the MicroMI design allows inexpensive lithium battery products to be used to simplify field microbiology and increase access to vital analytical microbiology testing.
在可控温度下孵育是基于培养的微生物学检测的关键步骤。要进行基于培养的微生物学检测，需要在实验室中使用传统培养箱。便携式培养箱可实现现场及资源有限环境下的微生物学检测，还能消除样品运输难题，将样品降解的可能性降至最低。最近的研究报道了适用于现场或离网使用的低成本便携式培养箱设计，但这些设计要么需要外部电源（如市电交流电源或12伏直流电源），要么依赖无恒温控制的被动加热。在此，我们报告一种用于消费电子产品的小型廉价不间断电源（UPS）产品，由锂离子电池组供电，可在小型便携式培养箱中实现恒温控制，无论有无外部电源都能保持精确温度。我们展示了一种适用于现场使用的两种尺寸的微生物移动培养箱（MicroMI）的开源设计。MicroMI由简单且广泛可得的组件构建而成，易于设置。开源设计可针对不同数量的样品进行定制。最小且最有效的设计使用真空隔热食品瓶，可使用更小、容量更低的UPS实现更长时间运行。较大的航空箱设计有空间容纳更多样品，但电池电量消耗更快。UPS在无外部电源的情况下可将典型的微生物培养温度维持长达24小时，这对于培养方法所需的典型孵育来说非常理想。电池容量、培养箱设计和外部环境温度都会影响无外部电源时的运行持续时间。我们通过使用琼脂平板、斜面培养和浸片进行经典微生物学检测以及生化检测，对MicroMI进行了验证。我们得出结论，MicroMI设计允许使用廉价的锂电池产品来简化现场微生物学检测，并增加获得重要分析微生物学检测的机会。
