Hardware Project

This year’s hardware project dealt with creating a lightbox for optogenetic experiments, which is inexpensive to build and easy to use. Lightboxes are an important part of every lab that deals with optogenetics, due to the fact that experiments in this field require light of specific wavelengths and are very easily disrupted by background lighting. This would normally mean that the experiment would need to be conducted in a completely dark lab, which can be difficult to achieve and may render the room practically useless for other experiments. A lightbox provides a compact way of creating a suitable environment. Unfortunately, buying such a box can be expensive, as it needs to be custom-built. We wanted to create a way of supplying future iGEM teams or other research groups with a relatively easy way of constructing their own box. Since we had planned on using optogenetics in parts of our overall project, the lightbox we built also came in handy for us.

Construction of the box

Building our box requires a small amount of work with electronics, as well as a bit of programming. Below we provide a sketch of the set-up, a brief description of the overall box and then an instruction manual to building the box yourself.

Our lightbox consists of a 3D-printed casing, a circuit board with LEDs, a slot for inserting your samples, and a compartment for electronics and wiring. Other lightboxes we looked at came in two parts: a basin for the sample and a lid with LEDs. Our tray mechanism enables construction of a more compact box and relieves stress on wires.

LEDs

We used three different wavelengths for our box: 460 nm (blue), 660 nm (red), and 780 nm (far-red). These cover the domains of frequently used optogenetic switches, such as LOV2, Phytochrome-B or Cryptochrome. In theory, the box’s repertoire of wavelengths can be quite variable. We got our LEDs and constant current sources from Led-tech. To control our box, we used a micropython, which functions much like an Arduino but is programmable via Python. Depending on one’s preference, an Arduino or Raspberry Pi could also be used here. The power source may be anything providing a voltage of at least 12V. In fact, we used old computer power supply; recycling can be a great thing!

An important aspect we wanted to include in our construction work is the use of 3D printers. These are a growing tool which provides people with the opportunity to create objects in silico and then make them in real life. While not absolutely necessary to build our box, having access to a 3D-printer will certainly help.

Construction of the box

Instruction manual

You will need:

1. 1 Circuit board (150mm x 100mm)
2. 1 microcontroller (micropython, Arduino or Raspberry Pi)
3. 3 constant current power supplies
4. 3 blue LEDs
5. 3 red LEDs
6. 3 red LEDs
7. 3 far-red LEDs
8. Heat-conducting pads
9. Soldering iron
10. Solder
11. Wire
12. A 3D-printer or something similar
13. A power supply that can provide a voltage of 12V (the easiest thing to use is an old computer power supply: you need the yellow(12V), red(5V) and black(neutral) wires; BE CAREFUL TO ALWAYS GROUND YOUR POWER SUPPLY AND DO NOT LEAVE ANY UNCONNECTED WIRES LYING AROUND)