(February 25th, 2014) Space… the final frontier! Not for cell biologists from Durham University. Their novel 3D cell culture system will soon begin its journey to the International Space Station.
In true Star Trek style, NASA has chosen a new 3D cell culture method developed by Stefan Przyborski and his team from Durham University, UK, to grow bone cells at the International Space Station (ISS) later this year. Led by Paola Divieti-Pajevic (Massachusetts General Hospital, Boston) and supported by the USA’s National Institute of Arthritis and Musculoskeletal and Skin Diseases, researchers aboard the Space Station will test the impact of gravity and how it affects ways bone cells communicate and grow. “We are very proud,” said Pryzborski. “For me, it demonstrates how scientists can take out new technology and apply it to their own research.”
The ability to grow cells in vitro is fundamental to today’s research, from understanding basic biology to the development of new therapeutic drugs. However, as a cell biologist, Przyborski was only too aware of the limitations present in conventional 2D culture methods. “I’m a cell biologist by background, and while working with stem cells, I recognised that the cells’ developmental potential and ability to differentiate was limited in vitro,” he said. “That’s why I developed a 3D solution to enable my cells to grow better and improve their function in vitro.”
Przyborski’s idea was to develop a way to prevent the cells from thinning out and forming a monolayer as they do in a standard petri dish. “Of course, in the body cells and tissues don’t behave like that at all, and the flattening process actually causes them to change their function as well as their structure,” he explained.
The solution involved creating a porous 3D scaffold out of polystyrene where the cells could just “hang out”, maintaining their three-dimensional structure. This way, cells can pile up on top of each other and form three-dimensional interactions with neighbouring cells, creating a tissue-like structure. The scaffold is only 200 µm thick, which means no cell is more than 100 µm from a source of nutrients. This is similar to an in vivo scenario, where it is estimated that most cells are no more than 150-200 µm away from a capillary.
The product is now commercially available under the name Alvetex, and the company, Reinnervate, boasts customers spread worldwide. Examples come from various labs, including a group of Irish and Austrian researchers assessing cellular oxygenation; as well as a group from Germany looking at factors regulating cellular migration in colorectal cancer.
In principle, this system can be used for virtually every type of cell, although for those that grow in a particular orientation, like muscle cells, it may not be the best option. “There are lots of ways of doing 3D culture and there’s not a single solution for everything,” said Przyborski. “Researchers need to select the appropriate method for what they’re trying to achieve. If they want to create a tissue-like structure, which is composed of different layers, then they would use microchips, if they wanted to create aggregates of cells they would use a hydrogel or a hanging drop. If they wanted a layered structure then that’s where our technology is the most appropriate.”
The team is now turning their attention to how long they can keep the cells in culture using profusion media. “We’ve got a system where we can pump media around the 3D culture to mimic blood flow, that’s something we’re working on at the moment,” said Przyborski, as well as “ways to propagate cells continuously in 3D”.
Photo: Reinnervate (edited)