Scientists have reported on a method that allows successful 3D bioprinting of adult stem cells.
The technique is intended to produce 3D tissues and miniature organs in the lab, which could be used in medical research or, clinically, to identify the best treatment for a particular patient. It could also one day be used to produce tissues for implantation.
'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,' said Dr Wenmiao Shu of Heriot-Watt University, Edinburgh.
'These could then be used for animal-free drug development and personalised medicine,' he added.
Researchers have previously used the technique with embryonic stem cells, but their use poses ethical issues and could also result in rejection if used to produce tissues for transplantation. By contrast, induced pluripotent stem cells (iPSCs) can be derived from a patient's own somatic cells, overcoming these challenges.
In a study published in Biofabrication, Dr Shu, whose team previously created a 3D printer that could 'print' hESCs, modified the technique to allow iPSCs to be printed. They showed that the cells were able to maintain their pluropotency after printing. They were also able to successfully differentiate into liver-like cells and expressed markers indicative of liver function.
In another study, published in the same journal, researchers from Tsinghua University, China, and Drexel University in Pennsylvania, demonstrated the use of bioprinting to produce 3D 'embryoids' using embryonic stem cells.
The researchers used 3D bioprinting to lay out embryonic stem cells into a 3D cell-laden hydrogel construct. Following the procedure, they found that approximately 90 percent of cells were viable and continued to function as expected, maintaining their pluripotency.
'Our next step is to find out more about how we can vary the size of the embryoid body by changing the printing and structural parameters, and how varying the embryoid body size leads to "manufacture" of different cell types,' said Rui Yao of Tsinghua University, who was a co-author on the paper.
Professor Wei Sun, lead of the team at Tsinghua University, said that in the longer term the team plans to enable different cell types to develop next to each other. '[This] would lead the way for growing micro-organs from scratch within the lab,' he said.