3D printing breakthrough could accelerate drug testing process

Researchers have used 3D printing to arrange human embryonic stem cells (hESCs) for the first time, an advance that could accelerate drug testing processes and eventually help to provide transplant organs on demand.

The breakthrough was published yesterday in Biofabrication.

Co-author of the study, Dr Will Wenmiao Shu, from Heriot-Watt University, said: ‘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.’

In the longer term, this new method of printing may also pave the way for incorporating hESCs into artificially created organs and tissues ready for transplantation into patients.

In the study, the researchers, from Heriot-Watt University in collaboration with Roslin Cellab, a stem-cell technology company, used a valve-based printing technique, which was tailored to account for the sensitive and delicate properties of hESCs.

The hESCs were loaded into two separate reservoirs in the printer and were then deposited onto a plate in a pre-programmed, uniformed pattern.

Once the hESCs were printed, a number of tests were performed to discern how effective the method was. For example, the researchers tested to see if the hESCs remained alive after printing and whether they maintained their ability to differentiate into different types of cells. They are also said to have examined the concentration, characterisation and distribution of the printed hESCs to assess the accuracy of the valve-based method.

In a statement, Shu said: ‘Using this valve-based method, the printed cells are driven by pneumatic pressure and controlled by the opening and closing of a microvalve. The amount of cells dispensed can be precisely controlled by changing the nozzle diameter, the inlet air pressure or the opening time of the valve.

‘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.’

Roslin Cellab will take the lead in developing 3D stem-cell printing for commercial uses.

Jason King, business development manager of Roslin Cellab, said: ‘Normally laboratory grown cells grow in 2D but some cell types have been printed in 3D. However, up to now, human stem-cell cultures have been too sensitive to manipulate in this way.

‘This is a scientific development that we hope and believe will have immensely valuable long-term implications for reliable, animal-free drug testing and, in the longer term, to provide organs for transplant… without the need for donation and without the problems of immune suppression and potential organ rejection.’

HESCs have received much attention in the field of regenerative medicine. They are originally derived from an early stage embryo to create ‘stem cell lines’, which can be grown indefinitely and differentiate into any cell type in the human body.

‘In the longer term, we envisage the technology being further developed to create viable 3D organs for medical implantation from a patient’s own cells,’ said Shu.