Already revolutionizing manufacturing, 3D printing technology also promises to revolutionize the field of biotechnology. While scientists have previously had success in 3D printing a range of human stem cell cultures developed from bone marrow or skin cells, a team from Scotland's Heriot-Watt University claims to be the first to print the more delicate, yet more flexible, human embryonic stem cells (hESCs). As well as allowing the use of stem cells grown from established cell lines, the technology could enable the creation of improved human tissue models for drug testing and potentially even purpose-built replacement organs.

The scientists printed embryonic human stem cells in laboratory conditions using a new valve-based technique developed by Dr Will Wenmiao Shu and his colleagues at Heriot-Watt's Biomedical Microengineering group. The hESCs were drawn from two separate reservoirs in the printer using pneumatic pressure and deposited onto a plate in a pre-programmed, uniformed pattern through the opening and closing of a microvalve. Dr Shu says that the amount of cells dispensed can be precisely controlled by changing the nozzle diameter, the inlet air pressure and the opening time of the valve.

After the hESCs were printed, the researchers conducted tests to see if the hESCs were still alive and if they were still able to differentiate into different types of cells. The accuracy of the valve-based printing method was also assessed by examining the concentration, characterization and distribution of the printed hESCs.

“We found that the valve-based printing is gentle enough to maintain high stem cell viability, accurate enough to produce spheroids of uniform size, and, most importantly, the printed hESCs maintained their pluripotency – the ability to be differentiated into any other cell type,” said Dr Shu. “To the best of our knowledge, this is the first time that hESCs have been printed. The generation of 3D structures from hESCs will allow us to create more accurate human tissue models which are essential for in vitro drug development and toxicity-testing. Since the majority of drug discovery is targeting human disease, it makes sense to use human tissues.”

The researchers believe the technology could also be used to create artificial organs and tissues that incorporate a patient’s own stem cells, thereby reducing the risk of the patient rejecting the organ and the need for immune suppression. This would also help address the global shortage of organ donors.

To commercialize the 3D printing technology, Dr Shu’s group has teamed with Scotland-based stem cell technology company Roslin Cellab. While the development of more accurate human tissue models for reliable, animal-free drug-testing is the initial goal, the longer term aim is to use the technology to create artificially created organs and tissues that incorporate a patient’s own stem cells. This would reduce the risk of organ rejection and the need for immune suppression and help address the global shortage of organ donors.

The team's findings are reported in the journal Biofabrication.

Source: Heriot-Watt University