A multidisciplinary team of researchers found that coatings prevented infection in live mice and mapped strain on commercial implants applied to sheep spines to warn of various implant or healing failures.
“This is the combination of bio-inspiring nanomaterial design with flexible electronics to tackle a complex, long-term biomedical problem,” said study leader Qing Cao, professor of materials science and engineering.
Both of infection and device failure are major problems Cao with orthopedic implants, each affecting 10% of patients.
Strain detection and infection control
Several approaches have been tried to fight the infection, but all have serious limitations, he said: > Biofilms can still form on water-repellent surfaces, and coatings loaded with antibiotic chemicals or drugs wear out within months and become toxic. surrounding tissue with little efficacy against drug-resistant strains of bacterial pathogens.
Inspired by the naturally antibacterial wings of cicadas and dragonflies, the Illinois team created it. thin foil patterned with nanoscale pillars such as those found on the wings of insects.
When a bacterial cell attempts to attach to the foil the columns pierce the cell wall and kill it.
“Using a mechanical approach to kill bacteria allowed us to circumvent many of the problems associated with chemical approaches, while giving us the flexibility needed to apply coatings to implant surfaces,” said study co-author Gee Lau, professor of pathobiology.
On the back side of the nanostructured foil, where it contacts the implant device, the researchers integrated arrays of highly sensitive, flexible electronic sensors to monitor the strain.
Early Detection and Prevention
This could help doctors track the healing progress of individual patients, guide their rehabilitation to shorten recovery time and minimize risks, and repair or replace devices before they reach the point of failure, the researchers said.
The engineering team then teamed up with Annette McCoy, professor of veterinary clinical medicine, to test the prototype devices. They implanted the foils into living mice and monitored them for any signs of infection, even when bacteria were introduced.
They also applied the coatings to commercially available spinal implants and monitored the strain of the implants in sheep spines under normal load to diagnose device failure. The the covers served both functions well.
The prototype electronics required wiring, but the researchers plan to do so next developing wireless power and data communication interfaces It’s an important step toward clinical application for the coatings, Cao said.
They are also working to develop large-scale production of nanopillar-textured bacteria-killing foil.
“There are many potential applications for these types of antibacterial coatings, and because ours uses a mechanical mechanism, there is potential for places where chemicals or heavy metal ions — as now used in commercial antimicrobial coatings — would be harmful,” Cao said.