Continuous monitoring of bacterial growth is a critical step in the biotechnology industry and in biological labs. These measurements are typically taken using large and bulky spectrophotometers that do not fit into incubators for real-time monitoring. Moreover, continuous monitoring is labor-intensive as it requires multiple samplings.
Recent developments by researchers from Cork, Ireland have overcome these challenges by hacking a generic heart rate monitor to make a low-cost turbidity tracker. The team 3D printed a holder where an LED light can shine through, while the sensors’ photodiode can measure the amount of light coming in. The device, simply called the optical density measuring device (ODX) quantifies the turbidity of the bacterial solution in real-time and surprisingly performs similar to a benchtop spectrophotometer, the current gold standard.
The team also developed a smartphone app that notifies users when the turbidity of the bacterial solution reaches a certain value. The research, published in ACS Analytical Chemistry, is completely open-source, with instructions freely available on GitHub.
The authors show that with a little thought and a lot of tinkering, low-cost solutions (the ODX costs $25) can be developed for seemingly simple academic and industrial applications with huge implications.
GitHub link for all files, including materials list, 3D printing templates, and instructions for building the device: https://github.com/momos123/ODX
Study in journal Analytical Chemistry: ODX: A Fitness Tracker-Based Device for Continuous Bacterial Growth Monitoring