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Metallic implants—widely used clinically to replace diseased or damaged bone tissue—are not biodegradable and stay in the human body until removed surgically. The implants may also have problems with corrosion and could cause a negative reaction with the immune system. As a result, new polymer-based biodegradable implants are being developed to provide a needed alternative to metal.
Inspired by the structure of natural bone that provides a porous load-bearing scaffold to house soft biological cells, Assistant Professor Pranav Soman and his research team are using 3-D printing to create polymer scaffolding that can be filled with bone-forming human cells.
The polymer scaffold provides the initial support structure, while the cells eventually fill in and develop into bone, replacing the polymer that slowly degrades, providing a more natural replacement for the bone.
[...]The polymer component used in this work is called PCL, a Food and Drug Administration-approved biomaterial. This polymer is processed at a high temperature and then filled with gelatin laden with bone-forming cells that can deposit bone mineral or hydroxyapatite within the gelatin matrix. Once filled and exposed to ultraviolet light, the hybrid structure can both support the load and sustain the growth of the cells.
No more casts, no more pins.
(Score: 1) by DavePolaschek on Wednesday April 19 2017, @12:16PM (3 children)
Given that most titanium implants are projected to only last 15-20 years before needing replacement, something that the body helps fill in with bone would be a good alternative, especially if it lasts longer. Currently, after the first replacement, more bone needs to be removed. With old-school joint replacements, after your second set of replacement knees, you were pretty much out of bone to attach a replacement to. That's been helped by "resurfacing" replacement, in which only about 5mm of the surface of the joint is replaced, but surgeons are still reluctant to do a replacement for anyone younger than 50 because of the complications of tearing apart and replacing a joint a second or third time.
(Score: 2) by Grishnakh on Wednesday April 19 2017, @03:41PM (2 children)
Why would titanium implants have a limited lifetime? I thought that titanium had the unique property that it was completely bio-compatible and that bone grew into it. I thought the only problems with such implants was actually the polymer mating surfaces at the joint, not the titanium parts.
(Score: 1) by DavePolaschek on Thursday April 20 2017, @01:11PM (1 child)
Not sure why. Maybe it's just the teflon bits between the titanium pieces wearing out, or maybe it's the titanium-bone interface that goes bad, but the doctors all tell me that "titanium implants will last 15-20 years and then you'll have to get new ones."
If SN and I are both still around in the 30s, I'll try to remember to report back.
(Score: 2) by Grishnakh on Thursday April 20 2017, @04:32PM
Yeah, I think I heard it was the teflon bits wearing out; also, IIRC in a "titanium" hip replacement the socket goes into a teflon piece mounted in the pelvis. The titanium part is the ball part that sticks into the femur.