Tissue engineering could cut animal testing
If the microtissues can be engineered to behave like their counterparts in the body they could replace at least some elements of animal research. Ultimately, the hope is that they could be used to replace damaged tissues and organs in humans.
“There is a need for … tissue models that more closely mimic natural tissue already inside the body in terms of function and architecture,” said Jeffrey Morgan, a Brown professor of medical science and engineering.
“This shows we can control the size, shape and position of cells within these 3-D structures.”
The researchers, from Brown University, have grown the microtissues into complex three-dimensional structures using a newly-designed type of cup-like Petri dish made using agarose gel.
Because the cells do not adhere to agarose they tend to adhere to each other instead, which helps the formation of 3D structures. The agarose can also made into moulds to direct the shape of the microtissues.
Prior research has shown that cells can behave very differently when grown in 3D environments compared to setting such as conventional agar plate. For example, researchers from Brown demonstrated in 2007 that nerve cells grown in 3D deploy hundreds of different genes compared to those on regular Petri dishes.
In this initial series of experiments, reported on the website of the journal Biotechnology and Bioengineering, they report how the approach has already been used to assembled normal human fibroblast cells into rod-shaped tissues.
They also demonstrated that control over the position of individual cells and the rate of fusion within the microtissue could be achieved by modifying culture conditions such as pre-culture time.
They then harvested these living building blocks and then added them to more complex 3-D moulds shaped like a honeycomb or a donut. Those cells fused with liver cells in the more complex moulds and formed even larger microstructures.
“We think this is one step toward using building blocks to build complex-shaped tissues that might one day be transplanted,” said Morgan.
