*Bistable toggle switch in mammalian cells*
- great iGem project from Slovenia
"Biological drugs are being used ever more often as advanced drugs for the treatment of numerous diseases, due to their more specific mode of action. In current therapies the biological drugs are usually distributed more or less throughout the whole body, although each function should often be restricted to a specific organ or tissue. This can cause serious side effects, requires larger dosages and consequently raises the price of therapy. Our solution to this problem was to implant cells producing biological drugs inside the very tissue where the drug is required. The drug producing cells are safely sealed inside microcapsules that prevent cells from spreading throughout the body and protect them from destruction by cells of the host immune system. We constructed a device that allows implanted cells to produce different types of drugs while switching between those production states can be controlled from the outside by a physician, depending on the stage of the disease. We designed our device specifically for the therapy of hepatitis C or heart attack. Against hepatitis C the engineered cells produce a protein with antiviral activity, whose biological activity we have tested and confirmed. After the state of the cells is switched, a protein that improves liver regeneration would be produced. For the therapy after a heart attack we designed cells to suppress local inflammation and promote formation of new blood vessels only around the affected tissue. A physician may initiate self-destruction of the therapeutic cells and capsules by an outside stimulus when the therapy is complete or at any other given time. We believe our system to be safe, effective and applicable in the real world for the therapy of different types of diseases."