Bio-glass formed into therapeutic 3D-printed structures

The team from Imperial College London and the University of Milano-Bicocca in Italy have developed a bio-glass material that mimics the shock-absorbing and load bearing qualities of real cartilage, a flexible connective tissue found in joints and between vertebrae in the spine.

It can be formulated to exhibit different properties and the researchers aim to develop implants for replacing damaged cartilage discs between vertebrae. They believe it also has the potential to encourage cartilage cells to grow in knees, which has not been possible with conventional methods.

The bio-glass consists of silica and polycaprolactone that displays cartilage-like properties including flexibility, strength, durability and resilience. According to Imperial College, it can be made in a biodegradable ink form, enabling the researchers to 3D print it into structures that encourage cartilage cells in the knee to form and grow. It is also said to display self-healing properties when damaged, which could make it a more resilient and reliable implant, and easier to 3D print when it is in ink form.

One formulation developed by the team could provide an alternative treatment for patients who have damaged their intervertebral discs. When cartilage degenerates in the spine it leaves patients with debilitating pain and current treatment involves fusing the vertebrae together, which reduces a patient’s mobility.

The scientists believe they will be able to engineer synthetic bio-glass cartilage disc implants, which would have the same mechanical properties as real cartilage, but which would not need the metal and plastic devices that are currently available.

Another formulation could improve treatments for those with damaged cartilage in their knee, say the team. Surgeons can currently create scar-like tissue to repair damaged cartilage, but ultimately most patients have to have joint replacements, which reduces mobility also.

The team are aiming to ‘print’ tiny, biodegradable scaffolds using their bio-glass ink. These bio-degradable scaffolds would provide a template that replicates the structure of real cartilage in the knee.

When implanted, the combination of the structure, stiffness and chemistry of the bio-glass would encourage cartilage cells to grow through microscopic pores. The idea is that over time the scaffold would degrade safely in the body, leaving new cartilage in its place that has similar mechanical properties to the original cartilage.

Professor Julian Jones, one of the developers of the bio-glass from the Department of Materials at Imperial, said: “Bio-glass has been around since the 1960’s, originally developed around the time of the Vietnam War to help heal bones of veterans, which were damaged in conflict. Our research shows that a new flexible version of this material could be used as cartilage-like material.

“We still have a long way to go before this technology reaches patients, but we’ve made some important steps in the right direction to move this technology towards the marketplace, which may ultimately provide relief to people around the world.”

The researchers have received funding from the Engineering and Physical Sciences Research Council to take their technology to the next stage. They are aiming to conduct trials in the lab with the technology and develop a surgical method for inserting the implants. They will also work with a range of industrial partners to further develop the 3D manufacturing techniques.