Hardware
Our project requires both red and green light to regulate the growth and metabolism of E. coli. According to the records of the published paper[1] , we purchased the led strip with the following parameters.
The red peak wavelength of the LEDs is 650 nm, the green light is 520 nm, and the peak wavelength of our LED is slightly different[1], but our LEDs can still regulate the growth and metabolism of bacteria well. When we performed multiple sets of parallel tests in the entire shaker, we chose to attach the LED strips directly to the shaker plate and ensure that the intensity of the LEDs received by each conical flask remains the same. The following video shows the performance of LED strips.
When fermentation and characterization of light sensors was tested in a few conical flasks, lightening boxes, instead of LED strips were made to cover the entire conical flask. 3D printer was used to print the backbone of the boxes, and then the LEDs were connected onto the boxes, as well as a three-wire controller required for voltage change. The working video is illustrated below.
As for 24-well plates, we also designed a special light device for it, as well as control of modes such as variable voltage (change brightness), discoloration, and strobe. The devices can be placed directly on the shaker with a 24-well plate, and the cost per unit was pretty low. The working video is illustrated below.
References
[1] Schmidl, S. R., et al. "Refactoring and optimization of light-switchable escherichia coli two-component systems. " Acs Synthetic Biology 3.11(2014):820.
[2] Miliasargeitis, Andreas, et al. "Automated optogenetic feedback control for precise and robust regulation of gene expression and cell growth." Nature Communications 7(2016):12546.