Finding a workable alternative to animal testing is one of the most important efforts currently under way in the medical world. Not only is the method not all that effective, with numerous drugs that look promising when testing on rodents falling short during subsequent clinical trials, but it's also considered to be unethical by many people. Now, researchers at the University of Toronto have made a breakthrough, creating a new platform called AngioChip, which provides a complex, three dimensional structure on which tissue can be grown that mimics functions of the human body.
The idea of "organ-on-a-chip" devices certainly isn't new – they even won the Design of the Year award last year – but AngioChip looks to provide a significant evolution of the concept. Whereas previous efforts have relied on a single layer of cells, the new device takes a three-dimensional approach.
Constructed from a polymer called POMaC, which is both biodegradable and biocompatible, the device is made up of thin layers stacked on top of one another to create a 3D structure. Each layer is stamped with a pattern of channels, each just 50 to 100 micrometers wide. As layers are added to the device, UV light is used to cross-link the polymer, binding each layer to the one below.
Once construction is complete, the finished chip is bathed in a liquid containing living cells, which adhere to the device and begin to grow as they would inside the body. The finished chip works inside a normal cell culture dish, and doesn't require any pumps or vacuum lines.
Using that method, the researchers were able to construct model versions of liver and heart tissues that function just like the real thing. When the chip was seeded with heart cells, the polymer scaffolding even contracted with a regular beat, much the same as heart tissue in the body. The lab-grown liver tissue was equally impressive, producing urea and metabolizing drugs. Impressively, the different tissues can also be linked together via blood vessels, allowing scientists to observe interactions between them.
It's still early days, but AngioChip could well be the next step in organ-on-a-chip technology, with the potential to one day replace animal testing. The complexity of the platform would allow drugs to be tested for potentially dangerous side effects, working not just with individual model organs, but with linked tissue, providing a better picture of effects throughout the body.
The researchers also believe that such lab-grown tissue could one day be implanted into the body to repair damaged organs, with the polymer scaffolding biodegrading after a few months.
Right now, it takes a long time to make a single AngioChip, with each device made by hand. Looking forward, the team will look into ways of mass producing the chips, allowing for widespread testing and use.
The research was published in the journal Nature Materials.
Source: University of Toronto
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