Growing rates of implant infection and the increasing level of antibiotic-resistant bacteria have some surgeons nervous, and rightfully so – antibiotic-resistant bacteria can cause infections that are difficult and sometimes impossible to treat.
“Antibiotic-resistant bacteria are being found in patients who have never taken antibiotics in the first place,” said Thomas Webster, professor & department chair of chemical engineering at Northeastern University, at the North American Spine Society’s annual meeting this year.
But Webster and his research team have developed a way to use nanoscale features on the implant’s surface to combat bacteria, while encouraging bone growth.
“It’s clear that cells in our body reside in and make nano-materials,” he said. “It’s not just about biologically-inspired materials or mimicking the body – you can actually use nanotechnology to control surface energy of materials.”
By altering the surface of an implant with nanoscale features, researchers can change the surface properties without risking added toxicity from chemical treatments.
Webster and his team devised an equation to predict what size the nanoscale features need to be to give the right energy that will repel things like bacteria and promote bone growth and vascularization.
“Not all nano is created the same,” Webster explained to the crowd at NASS. “Just because you’re creating a nano-scale surface on an implant does not mean you’ll see the same results.” Changing the geometry and the size of the features will ultimately change the properties of the surface, so optimization was a big part of their process.
Last year, Tyber Medical licensed the technology from Northeastern University for use with its headless screw system. The BioTy surface treatment won FDA clearance in March of this year.
Webster reported that in-vitro analysis showed significant reduction of bacterial colonization for a variety of bacteria, like 95.6% for S. Aureus and a reduction of 81.1% for ampicillin resistant E. Coli. While these rates aren’t perfect, Webster says his team is impressed with the scope of the treatment and that they will continue to work with Tyber to optimize the solution.
He also said that the different surface properties induce variable levels of bone growth which, when properly controlled, could be differentiated for a permanent or temporary implant, while still maintaining its antibacterial properties.
“We have yet to find bacteria that this approach does not work for,” he said.
