Team:Concordia/testingef
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This year, our iGEM team representing Concordia University aims to design Combat Cells, a novel adaptation of the popular and engaging TV show "Robot Wars". The project concept involves the design and battling of ‘cellular robots,’ providing a new spin on synthetic biology for the scientific community. Our project consists of equipping cells with nanoparticles and having them battle one another in a controllable microfluidic device. Through this, our intention is to create and broadcast a web series through which we can entertain, educate, and inspire the public to participate in synthetic biology, and even create their own Combat Cells. The project encompasses three phases: nanoparticle synthesis, nanoparticle attachment, and analysis of cell survival on a microfluidic chip.
Nanoparticle Synthesis
To generate nanoparticles, we are harnessing the reductive powers of plants such as garlic, aloe vera and cabbage. Plants possess a variety of biomolecules that are capable of reducing and stabilizing metal ions to form nanoparticles. The sizes and shapes of nanoparticles can be manipulated by varying the amounts of plant extract and metallic solutions used for synthesis. Using a Transmission Electron Microscope (TEM), the nanoparticles synthesized can further be characterized. In this we aim to develop optimized methods for controlling the shapes and sizes of the nanoparticles using plant-mediated synthesis. Furthermore, incorporating this eco-friendly and cost-effective approach to synthesizing nanoparticles will allow our project to reduce the amount of waste we may produce during nanoparticle synthesis.
Beyond this, other methods of nanoparticle synthesis are used known as chemical and recombinant synthesis. Martin and Turkevich methods are used for chemical nanoparticle synthesis. Martin uses the strong reducing power of sodium borohydride to reduce gold nuclei into small gold nanoparticles in the 3-6nm diameter range. The gold solution that is being reduced, also contains trisodium citrate whose ions will cap and stabilise the gold nanoparticles. The Turkevich method uses the moderate reducer and strong stabiliser trisodium citrate whose reducing power is increased by heating the solution containing silver nuclei. This reduction of silver nuclei would lead to formation of nanoparticles in the 40-60nm diameter range. The recombinant method will involve the expression of the MelA gene, which will lead to the formation of eumelanin. This protein will in turn reduce the gold nuclei within E. coli cells and will intracellularly form gold nanoparticles. FhuA-GBP, a transmembrane protein linked to a gold-binding peptide, will be expressed in order to induce extracellular display of gold nanoparticles.
Nanoparticle Attachment
The next step following nanoparticle synthesis is nanoparticle-cell attachment. To do this, our team’s goal is to develop an effective linkage method between the nanoparticles and the cell’s surface, using both model organisms Escherichia coli and Saccharomyces cerevisiae. One of our methods includes the creation of a gold “Nanoshell” made from gold nanoparticles coated with L-cysteine surrounding the outer surface of yeast cells. Another one of our methods involves involves coating silver nanoparticles with polyelectrolytes and attaching these to the surface of both yeast and E. coli cells. We intend to study the relationship between nanoparticle abundance as well as localization on the protective qualities offered to the cell by nanoparticle cell coating.
Battle on a Microfluidic Chip
Microfluidic chips with varying channel diameters will be designed using AutoCAD and printed onto photomasks which will act to transfer the generated pattern onto the chip. The customized chips will incorporate a battledome where two differently nanoparticle-coated cells will be forced to physically interact and ‘battle’. During this battle, the team will compare the relative protective abilities of the different nanoparticle coatings in order to determine which type of nanoparticle-cell combination is the ultimate winner! In parallel, the nanoparticle-coated cells in the microfluidic chip will be exposed to different physical and chemical “obstacles” such as varied temperatures, salt concentrations, differing pH environments, and so forth, in order to test the protective abilities of the nanoparticles. The potential for colored pigments to travel through the cell membrane as a result of damage from the cell battle will be used to define a winner and a loser.
Ultimately, we envision a multi-team Combat Cells league in which every team has a unique nanoparticle synthesis method and attachment strategy that can be demonstrated through a entertaining webseries. It is our team’s hope that individuals of all ages and educational backgrounds will participate under the guidance of experienced coaches to develop novel strategies to design their own Combat Cells using innovative biotechnological approaches.
