Current methods of signalling distress and aiding emergency rescue are far from ideal. There are devices with GPS, which require electricity and can malfunction in water or cold temperatures. You have only one chance with flare gun and signal fire. Whistles have a limited range. Although some life vests have reflective stripes, visibility in ocean rescue is still inadequate.
Some examples of current distress signalling. From left to right GPS device, flare gun and signal fire.
To fulfill the need, we started to design a bioluminescence life jacket. It would be a novel method of signalling that functions in many environments where humans can survive, unlike electronics. Furthermore, by optimising the medium bacteria will be in, the biological system would ideally be sustaining itself longer than 10 days (which is the longest humans can survive without water1) longer than current equipment.
As biologists, Robin and I have identified the most promising approaches to engineer bioluminescence:
- Making the bacteria sporulate and re-germinating the spores2
- Keeping the bacteria alive but preventing luminescence until the emergency
- Extracting and stabilising luciferase proteins
Then we built our first prototype,
Photograph of our first prototype. LED lights are used to represent bioluminescent bacteria.
The more we dig into ways of engineering bioluminescence, the more challenges we came across with. Making a living organism express extremely bright bioluminescence bright would be a metabolic burden on itself.
Robin and I decided to use cell-free protein synthesis (CFPS) coupled with nanocapsules. This system overcomes the requirement of keeping the bacteria alive. As the nutrients won’t be wasted to other pathways, we will be able to produce bioluminescence even brighter.
Then, we evolved our idea to an ‘Emergency Balloon’. The balloon will be kept non-inflated while not being used, stored in a wearable gear like a bracelet and will still be attached to the user (by a cable?) upon inflation.
Luciferin and luciferase will be stored in separate nanocapsules. Breakage of nanocapsules will allow physical contact of luciferin-luciferase and produce bioluminescence. This system alone would have a short half-life. To make the system sustainable for a long time, we have added synthetic cells producing luciferin and luciferase. Construction of synthetic cells will be based on the ‘PURE’ system which is a standardised tool for CFPS3. The PURE system will be trapped inside the nanocapsule as well, but a part of the transcription-translation machinery crucial for protein synthesis (probably transcription factors) will be outside of the nanocapsule. Thus, until the nanocapsule breaks synthetic cells won’t produce luciferin and luciferase. All the nanocapsules will be present inside the non-inflated balloon. When the balloon is inflated, nanocapsules will be under pressure and they will break, activating bioluminescence. The balloon will deploy automatically when the pin of the helium (allowing it to fly) filled cylinder is pulled. This will be stronger signal then just wearing a life jacket, and will have wider range of applications.
A simplified representation of how the ‘Emergency Balloon’ would work
The design of the ‘Emergency Balloon’ is underdevelopment. Also, there are still issues to be addressed including the nanocapsule choice, intensity and duration of bioluminescence. With contributions of all our teammates, we hope to overcome all the challenges and develop our ‘Emergency Balloon’ in the following weeks.
Word count: 500
Written by Elif Gediz Kocaoglan
References:
- Alice (2017). “One Cannot Live on Water Alone.” Go Ask Alice! Columbia University, goaskalice.columbia.edu/answered-questions/one-cannot-live-water-alone.
- Van Vliet, S. (2015) Bacterial Dormancy: How to Decide When to Wake Up. Current Biology 25,
- Rampioni, Giordano, and Francesca D’Angelo. “Synthetic Cells Produce a Quorum Sensing Chemical Signal Perceived by Pseudomonas aeruginosa.” ChemComm, vol. 54, Feb. 2018, pp. 2090–2095. Royal Society of Chemistry, doi:10.1039/c7cc09678j.