Creating bone and cartilage via 3D printing

Nieves Cubo, a researcher, is using 3D printing to generate human tissue that could replace metal prostheses.

Generating tissue and organs tailored for each patient using their own cells is no longer science fiction, but science, thanks to bioprinting. The use of 3D printing in this area is being studied, and it will soon reach hospitals and laboratories. The future of personalised medicine is now here. 

Nieves Cubo, engineer and researcher, is studying the creation of human tissue (bones and cartilage, among others) with the help of 3D printers. She is carrying this out from the Faculty of Pharmacy in the Complutense University of Madrid and the CSIC's Institute of Polymer Science and Technology  

“Rather than artificial or metal prostheses, we're looking for something that can really integrate with the body. We're no longer talking about replacing, but regenerating”

Nieves and her team print polycaprolactone (PCL) grids with an Hephestos 2 and a Witbox 2. These printers don't simply use a normal extruder that melts PLA at more than 200ºC, depositing it on the bed to create a 3D object, but an extruder with a needle added to it that applies the cells in a controlled way

Cartilage or bone cells are placed on these grids and after some time the cells invade the whole prosthesis, reproducing and replacing the material for another natural one, either bone or cartilage, whatever the case may be. “We're just taking advantage of what biology does in nature, we give the cells what they need to develop themselves”, she says. 

Two methods are currently being trialled: the first examines the possibility of implanting a 3D printed grid with cells into the broken area of bone or cartilage. These cells would then start the regeneration process from within the body. The polycaprolactone (biodegradable) would eventually disappear, leaving behind fully rebuilt tissue. Mechanical tests are currently being performed on the materials to see if this method is feasible. According to Nieves, “it would be best to place it into the body as soon as possible, but I think the cells would quickly degrade the material causing it to collapse: this option isn't viable”.

The second method looks into the creation of a supportive ecosystem in the laboratory, where the cells would be able to rebuild human tissue. This would then be implanted into the patient, or it could be used for other research purposes. The result: a “prosthesis” with far more advantages than metal ones. It is made to measure and there are less chances that the body rejects it.

It should be noted that nature can also err. Sometimes cells within the human body form bone where cartilage should be. This is called calcification, and preventing this from happening in the laboratory is one of the challenges faced by Nieves and her team.

Avoiding animal testing

Printing human tissue can also put an end to clinical trials with animals, which form a compulsory part of the approval process for a medical technique or medicine.

“If we have something in the laboratory that behaves exactly like the human body, we could test cosmetics and pharmaceuticals on it rather than using animals. It would prevent them from suffering and be less costly”

In the past, this researcher designed a printer for creating human skin. The study is currently in the clinical phase and it won't be long before it reaches hospitals and laboratories. Thanks to this printer, in a period of two weeks various square metres of skin can be “manufactured” and used to regenerate, for example, extensive burn areas.

She is also working toward the dissemination of this technology via a collaborative platform that she has created called OpenBioprinting, where researchers, physicians and anyone interested in this field can learn and share their knowledge.

In 2015 Nieves explained her achievement in a TEDx talk. In this talk she recognised that all her achievements are owed to her lecturers who taught her about 3D printers when she studied at the Carlos III University of Madrid.

“All those people who were there, who taught us how to assemble the printers and how to work with them, when something went wrong they'd say: don't worry, keep on trying, you can do it, it doesn't matter if you're not in MIT. Thanks to all those people, today we are able to print human skin. And, if in the future one of us needs a small part of our body made via this technology, perhaps we'll be able to make it thanks to them”.