The development of our project surrounding the topic ‘bioluminescence’ has moved on significantly since the first weeks of the semester both in terms of the ‘what’ and ‘how’ we are going to achieve. Our initial idea to make a bioluminescent life vest using the marine bacteria Vibrio harveyi. This idea proved to be exceptionally difficult for a number of reasons:
- V. harveyi requires mechanical stimulation to become fully luminescent.
- The project would have required significant genetic modification ion and engineering for which we had little time or resources. Additionally, the use of genetically modified organisms as a tool in precarious and often life-endangering situation would have meant that the product would have been most likely unusable due to legislation surrounding such organisms.
- We felt that a life vest had a limited use of applications in the real world.
For this reason, we decided to Use a cell-free protein synthesis system with nano-encapsulation of the active and necessary constituents of a bioluminescence to create a more stable, reliable and powerful bioluminescent signal. Additionally, we shifted the idea of a bioluminescent life jacket to a balloon that can be deployed by a person who is stranded to give a distress signal as well as cast light.
Scientifically, the use of this system is perfect for an inflatable device. The nanocapsules may be engineered to degrade and disassemble when subject to a variety of conditions such as temperature, pressure or pH changes [1]. As well as this, they totally isolate their contents from exterior environments and are easy to express genetically (Fig. 1).
Figure 1: The process of encapsulating complex compounds such as RuBisCO requires very few genes. By simply inserting the gene for RuBisCO (RbcL) and carbonic anhydrase (CcaA) together with a targeting peptide sequence next to the encapsulation gene makes a capsule form perfectly. The ease of this process is unprecedented and has been demonstrated for a large variety of compounds. Figure from [2]
Indeed, the use of these capsules as a barrier system between the active ingredients of the bioluminescent machinery allows us to only activate them when the capsules break (through an increase in pressure as gas enters the balloon through deployment. The distinct capsules containing the synthetic cells, activating transcription factor, luciferin and luciferase may then be allowed to mix, kick-starting bioluminescence. The synthetic cells from the cell-free system can be governed using the ‘PURE’ system, a well known standardised quorum sensing signalling method [3].
The system has been blueprinted below (Fig. 2).
Figure 2: The diagram shows how the balloon, attached to a helium canister contains the necessary constituents of a bioluminescent reaction. Upon release of the (innert) helium, the capsules will break and the luminescent process may begin.
This system will be more reliable than the previous design using live bacteria. A cell-free system alleviates concerns surrounding the use of GM bacteria whilst also allowing for a longer lasting bioluminescence to create a more powerful rescue signal. Additionally, the use of a floating balloon also makes the signal more applicable to a number of different applications such as extreme sports, mountaineering and traditional rescue scenarios.
By Robin Bishop
Word count: 493
References
- Rahmanpour, R. and Bugg, T.D.H. (2013) Assembly in vitro of Rhodococcus jostii RHA1 encapsulin and peroxidase DypB to form a nanocompartment. FEBS Journal 280, 2097–2104
- Giessen, T.W. and Silver, P.A. (2017) Engineering carbon fixation with artificial protein organelles. Current Opinion in Biotechnology 46, 42–50
- Rampioni, Giordano, and Francesca D’Angelo. “Synthetic Cells Produce a Quorum Sensing Chemical Signal Perceived by Pseudomonas aeruginosa.”, Royal Society of Chemistry, ChemComm, vol. 54, Feb. 2018, pp. 2090–2095.