Thermo-responsive Antibiotic-Eluting Coatings for Treating Infection near Orthopedic Implants
Abstract
The clinical effectiveness of orthopedic devices to restore the function of joints has been well established yet there is a lack of development in associated infections. As the demand for orthopedic surgeries continues to rise, infection remains a growing problem and one of the main reasons for revision surgeries. Bacterial contamination of the surgical site followed by adhesion of bacteria onto the surface of orthopedic devices leads to the formation of a biofilm which is a common initiator for infection. As a result, infection in the orthopedic field is commonly defined as orthopedic device-related infections (ODRI). There are limited options to treat ODRI, with revision surgery being the most common standard of treatment involving multiple surgeries to replace the infected component, but this approach is very expensive and can reduce the quality of life for the patient. Although the use of antibiotic carriers such as poly(methyl methacrylate) (PMMA) bone cement and calcium sulfate have shown promise, their ability to control the amount and rate of drug release remains a challenge. In this study, I have investigated a novel approach in using induction heating (IH) to not only directly kill bacteria and inhibit biofilm formation but also achieve on-demand externally triggered release of antibiotics from a poly(ester amide) (PEA) coating. The PEA coating has a glass transition temperature (Tg) of 39 °C, just above physiological temperature. I demonstrated that by heating the PEA above its Tg, either by direct heating or IH, the release of antibiotics can be accelerated due to the increased mobility of the drug in the PEA film in its rubbery state. The use of an intermittent IH protocol paired with an antibiotic-loaded PEA coating leads to a synergistic reduction in biofilm formation and live bacteria on the surfaces of the coating. This new technology provides a promising new approach to potentially prevent and treat implant-associated orthopedic infections.