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Biodegradable 3D Printing Materials, Bone Fractures and the $6 Million Man!
Posted on December 22nd, 2016 by Dr. Sina Ebnesajjad in Chemical Manufacturing Excellence
For five seasons from 1974 to 1978 a series called The Six Million Dollar Man aired on the television. It featured the ruggedly handsome NASA astronaut Colonel Steve Austin (Lee Majors) who was severely injured in the crash of an experimental lifting body aircraft. Austin was “rebuilt” in an operation that cost six million dollars. Now, that was quite a sum forty years ago.
His right arm, both legs and the left eye were replaced with “bionic” implants that enhanced his strength, speed and vision far above human norms: he could run at speeds approaching 100 km/h, and his eye had a 20:1 zoom lens and infrared capabilities, while his bionic limbs all had the equivalent power of a bulldozer. He used his enhanced abilities to work, of course, as a secret agent for the US Office of Scientific Intelligence (imaginary office).
Alas, forty years has not been long enough to get us quite there in the real world. The good news is mankind is making progress in repairing fractures and osteological problems using novel devices and implants. We will have virtually no chance of approaching Colonel Austin’s strength and speed but may well heal from a nasty bone fracture even avoiding amputation. (Never mind a career as a secret agent!)
The process of healing from fractures is usually slow, painful and varies based on the severity of the fracture. Sometimes, all that is needed is a cast or brace; however, more severe fractures can require surgery and the implantation of metal devices such as plates, screws, and rods to stabilize the bone while it mends. According to researchers at the University of Pittsburgh, traditional bone implants are composed of metals such as stainless steel, titanium, or PEEK, a polymer material that is non degradable, and remain in the body unless surgically removed. These metal implants are strong and resilient, but can result in further complications such as infection (Source www.4spe.myindustrytracker.com/en/article/104429?utm_source=SparkPost-4spe&utm_medium=newsletter&utm_campaign=4spe-2090-s-en-291016).
There are exciting advances in the use of biodegradable materials for bone repair purposes. The choice between using degradable and non-degradable devices for orthopedic and oral surgeries must be carefully weighed. Traditional biodegradable devices for osteosynthesis have been successful in low or mild load bearing applications. However, continuing research and recent developments in the field of material science has resulted in development of biomaterials with improved strength and mechanical properties. Options using biodegradable materials, including polymers, ceramics and magnesium alloys have attracted a great deal of attention for osteologic applications (Source: Materials, 8, pp5744-94, 2015; doi:10.3390/ma8095273, www.mdpi.com/journal/materials).
Medical researchers are looking for materials that can be more easily absorbed by the body. One such example is Evonik, a German specialty chemicals company. Their team of researchers is currently exploring biodegradable 3D printing materials that could be used to help heal fractured bones.
The products Evonik has created are not yet strong enough for large, load-bearing bones. Consequently, the company is exploring composite materials that reinforce biodegradable polymers with inorganic substances, such as calcium phosphate derivatives. These extra elements would make the materials both stronger and more biocompatible. Ultimately, researchers at Evonik aim to create a product that is not only biocompatible but also suitable for 3D printing. They recently announced a 3D printing materials partnership with HP Corp and are looking into composite materials from which 3D printed implants can be created. With the 3D printing technology, implants could be customized for the patient’s specific needs.
Evonik is not alone in its search for more suitable bone implants. Researchers at the University of Pittsburgh are also working to create 3D printed materials that are biodegradable and match the patient’s body. Their goal is to use minerals the body can absorb and discharge as the body heals. Dr. Prashat Kumta, who is conducting the research, explained, “Rather than implanting a screw or plate or joint, doctors could give the body’s own regenerative ability a more effective method to heal itself.” Just like Evonik, these researchers recognize the need for implants that are received more readily by the human body and that partner with its natural healing ability
Researchers from Bacterin International are working with Montana State University to develop 3D printed biodegradable surgical implants. “The concept is that you’ll have a 3D printer in the hospital that has autoclavable parts,” says Daniel Cox, a Product Development Specialist with Bacterin. After putting the sterile parts in the machine, and inserting a cartridge with the polymer, surgeons could print up exactly the right fragment on the spot.
Such a printer would save much more than time and money. “If you could print fast enough, you could save someone in trauma,” says Cox. “If someone’s missing a large enough section of femur or tibia, the only course we currently have is to amputate. Instead you might be able print that with a structurally sound polymer, which the surgeons could then implant and get it to eventually grow back into the patient’s own bone.”
There’s still “a lot of material science and things like that” to be done before there’s a bone graft printer in every hospital, for us larger animals. But it’s only a matter of time before 3D printing makes bone grafts more precise, cheaper, and speedily available to all.
All opinions shared in this post are the author’s own.
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Dr. Sina Ebnesajjad
President at FluoroConsultants Group, LLC