Team:Groningen/Template/MODULE/project/bandage/summary

Most people would think it is a bad thing to have a bacteria inside a bandage. And in many ways this makes a lot of sense, since most will damage wounds more then heal them. But this one won't! One of the biggest problems in hospitals right now, are drug resistant bacteria. However, despite the hesitation of a large group of people we think we can change a lot in bandages by having a inducible secreting system. In order to achieve a safe and easy solution a lot had to be discussed. This is our idea: Bacteria inside a hydrogel.

Lactococcus lactis would be the perfect candidate as a chassis for our engineered construct mainly because the unlikeliness of infecting humans and its ability to produce lactic acid. Of course there is a lot of expertise of L. lactis in our building which enables us to get acces to a lot of information. Before we started it was already proven that L. lactis cells can survive the harsh conditions of freeze drying¹. What also counted is that this bacteria is one of the few that people ever heard of because of it’s production in the cheese industry. this can make bringing this product to the community somewhat easier to do.

Although it’s a very save bacteria this still doesn’t solve the problem of having bacteria next to a wound. That’s why we designed the bandage, a containment device to store and activate bacteria at the right time. This bandage contains of 3 layers. A top membrane that diffuses oxygen and carbon dioxide, a middle membrane (gel layer) that contains freeze dried bacteria and a bottom membrane that makes sure our bacteria stay inside the bandage. This last membrane also allows diffusion of several molecules/peptides.

Although the needs for this bandage were pretty clear from the start, finding the specific materials was harder than we expected. For our top membrane we can make use of a polymer that the iGEM 2012 team used called TPX or polymethylpentene. This is available as thin, transparent sheets while it does keep its strength. For our middle membrane we were doing tests with polyacrylamide. While we know acrylamide is cancerous we needed a material that is easy to test with and quick to create. For a final product we were thinking of PMBVF/PVA. Our last part is the bottom membrane, and for this part a lot of research has been done already. We thought of using a Cellulose Nitrate membrane with a pore size of 0.2µm. This is small enough to keep the bacteria inside and large enough for the molecules to diffuse to either sides.

More information about the bandage design and the experiments are stated below.