Bio-printing transplantable tissues, organs one step closer

Imagine being able to walk into a hospital and have a full organ printed simply by clicking on the computer screen. It may soon become a reality!
Researchers have made a giant leap towards the goal of 'bio-printing' transplantable tissues and organs for people affected by major diseases and trauma injuries.
Scientists from the Universities of Sydney, Harvard, Stanford and Massachusetts Institute of Technology (MIT) have bio-printed artificial vascular networks mimicking the body's circulatory system that are necessary for growing large complex tissues.
"Thousands of people die each year due to a lack of organs for transplantation," said study lead author and University of Sydney researcher, Dr Luiz Bertassoni.

"Many more are subjected to the surgical removal of tissues and organs due to cancer, or they're involved in accidents with large fractures and injuries.
"Imagine being able to walk into a hospital and have a full organ printed - or bio-printed, as we call it - with all the cells, proteins and blood vessels in the right place, simply by pushing the 'print' button in your computer screen.

"We are still far away from that, but our research is addressing exactly that. Our finding is an important new step towards achieving these goals," Bertassoni said.
Researchers explain that cells need ready access to nutrients, oxygen and an effective 'waste disposal' system to sustain life.

This is why 'vascularisation' - a functional transportation system - is central to the engineering of biological tissues and organs.
"One of the greatest challenges to the engineering of large tissues and organs is growing a network of blood vessels and capillaries," said Bertassoni.
"Cells die without an adequate blood supply because blood supplies oxygen that's necessary for cells to grow and perform a range of functions in the body.
"To illustrate the scale and complexity of the bio-engineering challenge we face, consider that every cell in the body is just a hair's width from a supply of oxygenated blood.

"Replicating the complexity of these networks has been a stumbling block preventing tissue engineering from becoming a real world clinical application," said Bertassoni.
Using a high-tech 'bio-printer', the researchers fabricated a multitude of interconnected tiny fibres to serve as the mold for the artificial blood vessels.
They then covered the 3D printed structure with a cell-rich protein-based material, which was solidified by applying light to it.
Lastly they removed the bio-printed fibres to leave behind a network of tiny channels coated with human endothelial cells, which self organised to form stable blood capillaries in less than a week.
The study found that the bioprinted vascular networks promoted significantly better cell survival, differentiation and proliferation compared to cells that received no nutrient supply.