This 3D printed 'dough' could fix up your fractured bones
As it seems like the entire medical world is finally becoming aware of what the latest 3D printing technologies can do for them, it is hardly surprising that we hear about exciting new (bioprinted) medical innovations almost every week. This time, a team of scientists from the University of Nottingham show off an amazing 3D printing achievement. The team has developed a new 3D bioprinting technique that allows them to 3D print a thick paste filled with protein-releasing microspheres that can be used to greatly speed up bone regeneration after fractures.
This amazing innovation is the focus of a paper published in the journal Biofabrication last week. EntitledCell and protein compatible 3D bioprinting of mechanically strong constructs for bone repair, it hands bioprinting scientists a whole new avenue to explore: bioprinting at ambient temperatures as a viable option for the manufacturing of materials that can repair bone structures.
As Dr Jing Yang from the University of Nottingham, also one of the leading authors, explains, 3D bioprinting is a hot topic in the field of tissue engineering. ‘However it usually requires a printing environment that isn't compatible with living cells - and those materials that are compatible with living cells usually don't have sufficient mechanical properties for certain applications,’ he says. And that is exactly why they took a different direction. ‘Initially we're targeting the clinical application of this material as injectable bone defect filler,’ he says. ‘But we've postulated that its properties would make it highly suitable for use as a scaffold to reconstruct larger shapes, which could help with more complicated reconstructions - such as nasal reconstruction.’
And that temperature change is key to their success. Bioprinting technology typically relies on high temperatures (possibly through UV light or solvents). ‘These harsh conditions may prevent the incorporation of cells and therapeutic proteins in the fabrication processes,’ they write in their paper. ‘Here we developed a method for using bioprinting to produce constructs from a thermoresponsive microparticulate material based on poly(lactic-co-glycolic acid) at ambient conditions. These constructs could be engineered with yield stresses of up to 1.22 MPa and Young's moduli of up to 57.3 MPa which are within the range of properties of human cancellous bone.’
Incubated at just 37 degrees Celsius, these materials formed porous constructs. ‘Further study showed that protein-releasing microspheres could be incorporated into the bioprinted constructs. The release of the model protein lysozyme from bioprinted constructs was sustained for a period of 15 days and a high degree of protein activity could be measured up to day 9. This suggests that bioprinting is a viable route to the production of mechanically strong constructs for bone repair under mild conditions which allow the inclusion of viable cells and active proteins,’ they write.
The potential of this material is thus enormous, while 3D printing could be used to 3D print it in huge complex scaffolding structures. What’s more, the body temperature environment needed to manufacture this material means that production costs remain relatively low. This makes it quite easy to imagine complicated applications like filling bone fractures with this doughy material to not only make bones stronger during recovery from fractures, while the proteins themselves would speed up bone regeneration. While this 3D bioprintable paste is yet to reach clinical trials, this study could thus be the first step to a revolutionary treatment method.