Paula Hammond’s TED talk ‘A new superweapon in the fight against cancer’ explores the use of nanoparticles as a new way to treat cancer. Hammond is the head of the Department of Chemical Engineering at MIT. Hammond’s talk can be found on ted.com under the ‘science’ section.
Cancer consistently proves itself one of the greatest diseases we face as a species. Affecting up to one in three in our lifetime, not only does cancer strike fear into our species, but it has also proven its voraciousness with certain cancers possessing the ability to defy current medical treatment. This includes aggressive forms such as ovarian cancer, which has a 75% return rate after traditional chemotherapy, making it one of the hardest diseases to effectively treat.
But there is hope. Though a 100% effective cure is still a long way off, a potential breakthrough in the treatment of this disease with the use of biomechanics is being championed by Paula Hammond, head of MIT’s Department of Chemical engineering, who with her team are developing new technologies to kill cancer cells.
The team believe that by delivering a set of molecules known as siRNA into affected cells, they can be trained to block the genes that allow cancerous cells to reject traditional chemotherapy treatment. By dosing cancerous cells with siRNA to leave them weak and susceptible, and complimenting this with traditional chemotherapy treatment, it is hoped we can eradicate cancer far more effectively, including more aggressive strains.
However, this idea has so far been thwarted by the inability of siRNA to survive within our bloodstream or tissues due to the presence of enzymes, despite being able to survive within the cancerous cells themselves. So the question is, how do we deliver siRNA with chemotherapy drugs to cancerous cells without it degrading before it has a chance to reach where it is needed?
Hammond and her team believe they have found the answer in molecular engineering, in particular, the nanoparticle. Small enough to travel through the bloodstream and enter cancerous cells, the nanoparticles will be roughly one-hundredth the size of human hair. Inside the nanoparticle a nanometre-thin blanket of siRNA will be wrapped around the chemotherapy drugs to immobilise the drug-resisting genes within cells and allow chemotherapy to kill the affected cells.
This is made possible by siRNA’s negative charge, which means it can be protected by a layer of positively charged polymer. For those of you not familiar with the concept of charges, this effectively means the opposite charges of the siRNA and polymer of the nanoparticle will cause them to stick together, protecting the siRNA from enzymes in the bloodstream that would degrade it before it reaches the affected cells.
Yet we face another challenge that must be overcome to deliver the nanoparticles to affected cells, and that is our body’s natural immune system. Nanoparticles are detected by our body as foreign objects, and thus must be disguised to bypass this defence system. To do this, another negatively charged layer of polysaccharides found naturally in our bodies are placed around the polymer of the nanoparticle, allowing it to travel round our body disguised as water molecules unchallenged. This layer of polysaccharides also have the added benefit of being able to bind themselves to tumour cells, successfully deploying the nanoparticle to the cells to be destroyed.
The testing of the nanoparticles has proved extremely effective, managing to prevent the growth of a highly aggressive form of breast cancer in animals and even eliminate them in some cases. In comparison, the use of chemotherapy drugs alone failed to prevent growth of the tumours, allowing them to double in size over two weeks alone.
The best part is that Hammond’s nanoparticle can also be personalised, meaning that different layers of siRNA can be used to impede other mutations and tumour defence mechanisms, as well as putting different drugs into the nanoparticles core. By utilising the power of bio-engineering, Hammond and her team are opening the way for a new delivery system of treatment, and providing hope to the millions out there affected by cancer. Let us hope they can continue to make ground in their research.
