CompositesWorld
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27 CompositesWorld.com NEWS N E W S N S N E W S E N W S W According to ExoskeletonReport.com, there are at least 40 companies working on hard exoskeletons, both powered and unpowered, and more looking into soft exosuits (see Learn More). A few products tout the use of CFRP for lightweighting, but many rely on metals and plastics. Segl says exoskeletons naturally evolved from orthoses. Do compos- ites have any opportunity here? "Te question is whether it is an active or passive system," he responds. "Active means powered, and the issue is where the power comes from." Tough he acknowledges big steps are being made in energy storage, "If you need an exoskel- etal system to climb stairs, you are moving a 60- to 80-kg load upward, and a battery then also adds weight." He says that many exoskeletons are now more nearly robotic than orthotic, "but with energy sources gaining in ef- ciency, you might be able to integrate an active system via a composite with piezo- fbers. For example, look at NASA's folding systems for satellites. However, they are moving only grams in space and we are moving kilograms acted upon by gravity." Otto Bock has licensed two patents from Ekso Bionics (Richmond, CA, US), SIDE STORY The Center of Innovation for Biomaterials in Orthopedic Research (CIBOR) at the National Institute for Aviation Research (Wichita, KS, US) applies aerospace materials and process knowledge to orthopedic devices and works with aerospace manufacturers to pursue opportunities in the medical industry. It has two patents on the use of carbon foam as a bone-graft material to improve success in orthopedic implants. CIBOR research engineer Joel White describes it as "a very open-celled, rigid, carbon/ ceramic foam. Its structure mimics that of trabecular [spongy] bone, and its pore size and interconnected structure are able to be tailored for our applications." Extremely machinable, the material was being used by a local aero- space manufacturer as a core material for layup tools for the autoclave. It also ofered much lower thermal mass vs. aluminum or Invar. "The carbon foam performed really well in biocompatibility studies," says White, who also notes very good results with small animal bone-regeneration studies. These involved creating a defect in mice femurs and evaluating if the carbon foam aided regeneration. "We also have run studies where small samples were placed in muscle pouches and we were able to induce bone growth even in areas that would not normally support this," White adds. Trials in large animals (sheep) showed the carbon foam induced bone growth in an 8-mm by 18-mm hole in the femur. "We put our material in with BMP-2 [a protein which helps to induce bone growth] and were able to use dramatically less than the normal clinical dosage, but still achieved the same amount of regeneration in bone volume as we did with the full clinical dosage." White says the carbon foam is, indeed, amenable to bonding with diferent proteins and other osteoinductive materials, "which provides Orthopedics: Carbon foam fosters bone growth a lot of options." He illustrates the impact it could have on a common spinal fusion procedure. "They take the damaged disk out, and to fuse the vertebrae they insert a load-carrying device, like a PEEK intervertebral cage," he explains, noting, "We could put the carbon foam in the middle of this donut-shaped cage — instead of having to harvest a patient's own bone — and get good bone growth, because the PEEK alone does not support good bone formation. So the carbon foam provides a great synthetic conduit for bone growth through the implant and provides us with an exciting option." White says the carbon foam could eliminate the need to harvest the patient's own bone and reduce overall risk involved in surgery. See Learn More for news about CIBOR's research into CFRP use in implants for joint replacement surgery and the surgical instruments used to install them. . Carbon foam: Stimulating bone growth Performing well in tests as a bone-graft material for orthopedic implants, such as these PEEK intervertebral cages used in spinal fusions (left), carbon foam (50X micrograph, right) could potentially eliminate bone harvesting, reducing surgery duration and invasiveness. Source | CIBOR Bionics get a hand Composites were investigated for the bebionic3 hand, but lack of supplier interest, cost and a need for less brittle parts resulted in a metals and plastics makeup with a printed "carbon fber look." Source | Steeper Group Orthotics & Prosthetics