3D printing can now help human bone that has undergone major tissue damage to regenerate, according to research presented on January 19, 2016, at the “Printing for the Future” conference, which took place at the Institute of Physics in London, UK. Rapid Prototyping (RP) technology, the forerunner to 3D printing has been around since the 1980s, but it has only relatively recently become visible in the mainstream. Designers have used 3D-printing techniques to create a variety of items, from jewelry to individualized football boots and even a grandfather clock. One group is currently working on making an airplane wing.
The medical world has high hopes for 3D printing. Medical News Today has already reported on the use of 3D printing technology to manufacture part of the sternum that surgeons successfully implanted into a cancer patient. Patients who undergo cancer treatment or who experience a major fracture face losing a large volume of bone tissue. Synthetic bone substitutes can be used to replace the lost material, but making these tough enough for the job can be a challenge.
Temporary bridge will help patients after cancer treatment and fractures
Manolis Papastavrou, of Nottingham Trent University’s Design for Health and Wellbeing Research Group, in Nottingham, UK, is controlling the microstructure of a 3D-printed bone scaffold. The structure provides a temporary bridge that allows the regeneration of natural tissue. It can be made to match the individual’s exact size and shape requirements, based on medical imaging data. Being porous means that blood flow and cell growth can occur. The scaffold consists of the same minerals that feature in natural bone. It can dissolve as the patient recovers and new tissues replace it.
Researchers studied how the growth of crystals at sub-zero temperatures could be used together with 3D-printing techniques to structure a material at different orders of magnitude. They aimed to mimic structures that exist in biological materials. The team believes that combining 3D printing with freezing will enable a faster, more economical production of medical devices. Mr. Papastavrou, a PhD candidate, explains that the structure of a material, from the molecular up to the macro level, affects the toughness. Porosity would normally weaken a material, but the current technology is able to overcome that.
Future applications: implants and drug release control
Prof. Breedon, of Nottingham University, who helped oversee the research, calls it “a real step forward,” because it demonstrates how 3D printing can improve biomaterials without needing to achieve high resolution. Manipulating the growth of crystals in a 3D-printed material makes it possible to improve the microstructures of bone scaffolds. This will make them stronger and may help people to recover more quickly after a major illness or injury. The researchers told Medical News Today that no clinical studies have yet taken place, as the team is still working on improving the mechanical properties of scaffolds.
In terms of where the technology is at the moment, they told us:
“The material used (beta-tricalcium phosphate) has been proven to exhibit the appropriate biological properties. The process is still under development, the next step being the infiltration of this highly porous structure with a polymer to create a strong bio-composite. The research demonstrates the concept of combining 3D printing with other conventional scaffold fabrication techniques (freezing in this case) to obtain very fine micro-structural features. We believe it will take another 5-10 years for this technology to be used in a clinical setting.”
The researchers also said that the technology could be used in controlled drug release. The ability to tailor the level of micro-porosity makes it a good candidate for this function. “By controlling the freezing rate in different areas of a printed part,” they said, “it is possible to obtain porosity gradients, with gradually smaller pores towards its outer surface.” Mr. Papastavrou adds that metal orthopedic implants could be replaced with bone scaffolds in materials that can be broken down by the body. Surgeons also recently used 3D models to enhance the safety of surgery in which they transplanted a father’s kidney into his daughter.
NMT 7 February 2016