Symposium SM03: Advanced Neural Materials and Devices
Plenary Session Featuring The Fred Kavli Distinguished Lectureship in Materials Science

Symposium SM04: Beyond Nano–Challenges and Opportunities in Drug Delivery

Bingyun Li, West Virginia University

Immuno-Engineered Biomaterials Reduce Implant-Related Infections

Written by Arun Kumar

Current treatment options for reducing orthopedic implant-associated infections are restricted, says Bingyun Li from West Virginia University. They are weak in restricting the formation of biofilm (colonies of bacteria that stick to the implant surface) at the infection site post-implant. Once the biofilm is formed, clinicians are often left with limited treatment options to control the infection rate. The clinician has to introduce the patient to a strict, strong antibiotic regime for hindering bacterial growth, but it increases the risk of developing antibiotic-resistant strains. Antibiotic-resistant strains of bacteria can evade conventional treatment and host immune defense machinery to persist and mutate within the host cells.

This presentation focuses on the performance of nanotechnology-based strategies that can assist in reducing implant-related infection. Bingyun Li’s team has developed an in vitro model of Staphylococcus aureus (S. aureus) infected human cells to study the effect of immune-engineered biomaterials on bacteria. With prior knowledge that a cytokine (chemical messenger) Interleukin-12 (IL-12) delivered to the infected cells was able to effectively reduce S. aureus infection, the scientists visualized the use of nanocoatings and microcapsules of biodegradable polymers made out of poly(L-lysine) (PLL) and poly(L-glutamic acid) (PLGA) and functionalize it to carry IL-12. This polymer nanocoating of IL-12 can then be coated over implants to reduce any infection at the injury site.

The IL-12 PLL/PLGA polymer nanocoated orthopedic implants were then delivered into open-femur fractured rat models with S. aureus infection. The IL-12 nanocoated implants were able to reduce the infection rates in rats to 50% within 6 days and about 20% in 21 days compared to 100% and 90% infection at 6 and 21 days, respectively, in control rat groups. There was a sustained release of IL-12 from the polypeptide-coated nanostructures for 10 days which is higher when compared to “free IL-12 which only has a half-life of few hours.” Bingyun Li says. 

Another focus in Li’s lab is to use silver nanoparticles and drug-trafficking polymeric nanoparticles to target the intracellular S. aureus effectively. Li’s research group believes that the immune-engineered biomaterial can function as exemplary drug delivery vessels and actuate better immune responses against infections at the injury site.

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