Although joint replacement surgery typically goes off without a hitch, potentially-dangerous infections can occur after the operation. Scientists from New Jersey's Stevens Institute of Technology are addressing that problem, with a new type of highly-targeted bacteria-killing gel.
Developed by a team led by Prof. Matthew Libera, the gel consists largely of a negatively-charged polymer that gets loaded up with positively-charged antibiotics.
The idea is that surgeons would dip artificial joints into a bath of the gel for a few seconds, leaving a lattice-like array of tiny "microgel" flecks on the surface of those implants – each fleck is only about one one-hundredth the width of a human hair. The joints would then be quickly dunked in an antibiotic bath, allowing the microgels to absorb that medication.
After the artificial joint had subsequently been implanted in the patient's body, the microgels would hold onto their antibiotic payload until a bacterium approached. The electrical charge of that microbe would then cause the medication to be released, killing the bacterium. In in vitro tests, the gels proved to be quite robust, remaining stable and active for weeks.
Besides keeping bacterial biofilms from forming on implants, the technology would also allow relatively small doses of antibiotics to be applied and activated only where needed. By contrast, orally-administered antibiotics affect the whole body – this means that higher doses of them are required, potentially leading to the development of antibiotic-resistant bacteria.
Additionally, the microgels react to the presence of both active and dormant bacteria. Some other antibiotic implant coatings are triggered by byproducts of the microbes' metabolic activity, so they miss bacteria that have gone dormant.
The scientists are now working on gaining government approval for the technology, and on finding industry partners to develop it further. It's possible that the gel could also be used on items such as artificial heart valves or sutures.
"It only takes one bacterium to cause an infection," says Libera. "But if we can prevent infection until healing is complete, then the body can take over."
A paper on the research was recently published in the journal Biomaterials.
Source: Stevens Institute of Technology
