Fresh approach to "organ-on-a-chip" tech adds a third dimension, may eventually replace test animals
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" devicescertainly isn't new – they even won the Design of the Year award last year – but AngioChip looks to provide a significant evolutionof the concept. Whereas previous efforts have relied on a singlelayer of cells, the new device takes a three-dimensional approach.
Constructed from a polymer calledPOMaC, which is both biodegradable and biocompatible, the device ismade up of thin layers stacked on top of one another to create a 3Dstructure. Each layer is stamped with a pattern of channels, each just 50 to 100 micrometers wide. As layers are added tothe device, UV light is used to cross-link the polymer,binding each layer to the one below.
Once construction is complete, thefinished chip is bathed in a liquid containing living cells, whichadhere to the device and begin to grow as they would inside the body.The finished chip works inside a normal cell culture dish, anddoesn't require any pumps or vacuum lines.
Using that method, the researchers wereable to construct model versions of liver and heart tissues thatfunction just like the real thing. When the chip was seeded withheart cells, the polymer scaffolding even contracted with a regularbeat, much the same as heart tissue in the body. The lab-grown livertissue was equally impressive, producing urea and metabolizing drugs. Impressively, the different tissues can also be linkedtogether via blood vessels, allowing scientists to observe interactions between them.
It's still early days, but AngioChipcould well be the next step in organ-on-a-chip technology, with thepotential to one day replace animal testing. The complexity of theplatform would allow drugs to be tested for potentially dangerousside effects, working not just with individual model organs, but withlinked tissue, providing a better picture of effects throughout thebody.
The researchers also believe that suchlab-grown tissue could one day be implanted into the body to repairdamaged organs, with the polymer scaffolding biodegrading after a fewmonths.
Right now, it takes a long time to makea single AngioChip, with each device made by hand. Lookingforward, the team will look into ways of mass producing the chips,allowing for widespread testing and use.
The research was published in thejournal Nature Materials.
Source: University of Toronto
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