Z. Ryan Tian, PhD, and the other researchers are trying to perfect the coating’s thickness.
Researchers at the University of Arkansas (Fayetteville) selected metal titanium for the implant, because its mechanical strength and density are close to those of natural bone. Because the surface of many bone implants is too smooth, they chemically corroded the metal’s surface to generate a tough outside layer. “The new science here is that the scaffolding nanowires root deeply inside the substrate through the corrosion process and grow on the top, eventually forming the scaffold through the self-assembly process,” says Z. Ryan Tian, PhD, assistant professor of chemistry and biochemistry at the University of Arkansas.
“We needed a porous structure with large pores for a scaffold—at least 20 µm—so that the tissue cell could grow on the surface and integrate into the bone structure,” says Tian. “If the surface is too smooth, the tissue can’t adhere [to it] in the first place and will slowly fall off over time.” If the tissue falls off, the implant becomes weak and patients may need additional surgery.
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Researchers can control the nanowire scaffold’s kinetic parameters, including its pore size and concentration.
The researchers are working to optimize the coating’s thickness, which currently ranges from 5 to 40 µm. If the coating is too thick, the structure of the implant won’t be robust, according to Tian.
A provisional patent has been filed for the nanowire scaffold on biocompatible titanium. The researchers hope to publish more testing results about surface function and how to best induce fast tissue growth. They’re also looking for parties interested in pushing the commercialization of the technology.
Work on the implant coating was reported in the September 4 issue of the journal Chemistry of Materials.