Team:Hamilton McMaster/Hardware
Apparatus Used
Conventional methods for cell lysis, such as solvents or sonication, can be very expensive and may also harm the molecules - or proteins - of interest (POI). Our plasmid design would be able to lyse cell using only the power of light. Light, unlike chemicals or sound, is less likely to damage the POI and has a much lower relative cost.
Our envisioned plasmids would work in conjunction with a hardware setup. The transformed cells would be allowed to grow, with red light. All lights could be high-powered light-emitting diodes (LEDs) with narrow bandpass filters to ensure that only the required wavelengths of light are sent onto the cells (wavelength-bleed could cause accidental lysis activation).
An optical density (OD) sensor would take measurements periodically of the bacterial colony. Once the population grew large enough to warrant the extraction of the protein of interest (POI), the high OD value would trigger a computer system to switch the lights from red to green. The green LEDs would then cause the lysis of all the bacteria, thereby releasing the content of the cells, including the POI. As the lysis functions via endolysin and holin, the POI would be unharmed in the lysing process.
It may be helpful to preserve some of the bacterial colony alive, so as to start the next bacterial growth cycle quickly and thus as a method of optimizing this growth. Therefore, the lysing green light does not have to be shown at the entire bacterial colony, and can instead be shown on only a portion of the bacterial colony.
Once lysis has occurred, purification techniques can be carried out as usual.
A prototype for this lighting system was created, as shown below with accompanying circuit schematic.
A small version of the lighting device that controls the red and green lights is easily built. The bacterial cultures (in this example, in test tubes) are placed in a shaker. This shaker is completely enclosed in a box, lined with brushed aluminum foil (to increase light reflection within the system). The walls are covered with LED strips, with alternating red and green lights (in this example, panels of strips alternate, but alternating the strips themselves is possible). When the light system is OFF, both the Red and the Green lights are off. When the system is ON, the first stage is to be on the Red light setting. The Red light will induce production of the protein of interest. Once the OD of the bacterial cultures is high enough, the lights can be switched to Green. The Green light will induce cell lysis, from which standard protein purification can commence.
Schematic of circuit diagram
