Building Artificial Bone

Late-Eight writes "Researchers from the National University of Singapore, have recently developed a new way to make artificial bone from mineralised collagen. For some time scientists have tried to make nanosized artificial bone materials using various methods, And have recently turned their attention to mineralised collagen, a nanoapatite/collagen composite. This material is highly biocompatible and has the nanostructure of artificial bone. It could be used in bone grafts and bone-tissue engineering, among other applications."

Re:What about osteoporosis?

[imamac]

It's a little unclear from the article. Todays bone grafts (if donated) are performed with bone fragments, heads, grindings, etc from deceased donors. The donor bone is attached and actually broken down and replaced by the patients own osteocytes effectively replacing lost bone and ridding itself of the donor bone. I would assume this would be used for larger scale bone replacements.

Other bone reconstruction products

[jokestress]

For those interested in the topic, linear high-density polyethylene like Medpor [porexsurgical.com] can be cut to size and allows tissue growth into the material once implanted. It is mostly for craniofacial reconstruction and generally not used in weight-bearing areas, though. There's also hydroxyapatite (nicknamed HA), derived from coral. Pretty cool stuff.

SkepticalAs a bioengineer

[LightPhoenix7]

I'm a little skeptical of this. Not so much the concept - artificial bones aren't terribly difficult, unless you're going for an exact copy of bone composition, which isn't strictly necessary. In fact, it may not be optimal, depending on what it's used for.

Where I'm skeptical is in the immune response. I just attended a talk by someone looking to join our biomaterials department, and there was an allergic reaction to hyaluronan, a common in cartilage and various joint fluids. Just because we all have it, doesn't mean we won't react to it, or to chemical markers which have been missed.

Now, if they can successfully implant this into a host creature without an immune reaction, this might be a little bit more encouraging.

Critical Sized Defects

[Orleron]

A critical sized defect is when the gap of missing bone is so large that the two ends of the bone cannot grow back together. In a human or primate skull, this is about a 30-mm diameter hole. In a human long bone, it's about a 10-mm gap.

Generally, the thought is that we should stick something into the hole and let the bone grow into it, and that works to a point, but once the gap gets SO large that you're basically just putting a piece of plastic/collagen in to fully replace the bone, it simply won't work anymore. The bone will not grow through the whole thing. It will just grow into the ends of the scaffold and stop after a while.

So, I don't think this article was trying to say that, even though the media might be trying to hype it that way. Bone healing simply doesn't do this. You will never see a fake femur made of some kind of spongy plastic or collagen material that simply gets stuck in place of a bone.

No help for osteoporosis

[spineboy]

Osteoporosis is a medical problem - generally low amounts of estrogen prevent inhibition of osteoclasts, which therefore resorb the bone faster than the osteoblasts produce new bone.

This article is about surgical substitutes. Bone grafts today are for large visable defects that are either filled in, or are entire segments that are replaced. Generally the donated bone is only changed at the end - about 7mm worth. The rest of the dead, donated bone does not change over, and is generally weaker, and subject to infection at a higher rate.

Bone is complicated - it is a mineral scaffold which houses living bone cells. Most bone substitute just provides the scaffolding (conductive), and some actually induce new bone to form (Inductive), which relies on chemical signals to help cells differentiate into bone forming cells (osteoblasts).

This sounds like they have made a very natural appearing scaffolding, which makes it easy for the new bone cells to move in, and produce normal appearing bone. This is a nice tweak on the existing technology, but not a major breakthru which will help to form new large segmens of bone.