A 3D printer capable of printing stem cells derived from a patient’s own tissue without damaging their biological function has been developed by scientists, bringing the dream of patient-specific drug screening a step closer.

Known as induced pluripotent stem cells (iPS), the printed cells maintain the ability to make specialised cells, including liver, heart and brain cells, which can be used to test specific drugs.

Developed by a team from Heriot-Watt University’s School of Engineering and Physical Sciences and described in a paper published in the journal Biofabrication, the printer builds on their previous work, where they created a valve-based 3D printer that could print lab-grown stem cells without causing damage.

However, while the earlier version worked with stem cells grown from long ago-harvested embryonic stem cells, which only offer the potential for generalised drug testing, the new version has increased sensitivity, allowing it to work with iPS, which are specific to individuals.

“This study is the first to demonstrate that human induced pluripotent stem cells – that is stem cells derived from the adult patient’s own cells – can be bioprinted without adversely affecting their biological functions; that our 3D printing process is gentle enough to do this,” said Dr Will Shu, associate professor at Heriot-Watt University’s School of Engineering and Physical Sciences.

“In this instance we showed that after printing we could turn the stem cells into liver cells.”

The scientists, from Heriot-Watt University, are currently working on using the stem cells to make miniature 3D human tissues, which they will use to test pharmaceuticals, reducing the amount of animal testing that is required.

But in the long run their plan is more ambitious: to use tissue from specific patient’s cells to test whether a given drug will be effective, or result in adverse side-effects.

“The ability to bioprint stem cells while either maintaining their pluripotency, their ability to develop into all types of cells in the body, or indeed directing their differentiation into specific cell types, will pave the way for producing organoids, or tissues on demand, from patient specific cells,” explained Shu.

“These could then be used for animal-free drug development and personalised medicine.”

While the technology is some way from being useable in a clinical setting, it has enormous potential for medicine.

If the technology was advanced enough that it could be used in doctors’ surgeries and hospitals, it would enable patients to be prescribed drugs with a greater degree of confidence.

Instead of taking today’s trial and error approach, where a drug that is likely, but not certain to help, and switching treatments if the drug in question is either not helping or causing damaging side-effects, doctors would be able to prescribe a drug knowing how a given patient is likely to respond to it.

This would result not only in faster successful treatment for patients, but lower expenditure on inappropriate medication.