Development of intelligent implants for biofilm prevention in orthopedic prostheses

A multidisciplinary multiinstitutional group of investigators composed of microbiologists, MEMs scientists, and electrical engineers has been assembled to work on the design and development of intelligent implants to serve as orthopedic prosthetic devices for total hip and total knee replacements. Such a device would detect early signs of bacterial infection using MEMs-based biosensors, provide therapy from device contained reservoirs (based upon infectious agent) to prevent biofilm formation and monitor treatment effectiveness and antimicrobial stores while simultaneously providing for telemetric monitoring of all processes by a physician. Two to three percent of total joint replacements fail due to chronic eradicable bacterial biofilm infections. The only recourse for such patients is the traumatic removal of the implant which results in additional bone loss, extensive soft tissue destruction, months of forced bed rest with intravenous antibiotics, and significant loss of quality of life due to complete loss of mobility. These morbidity concerns combined with very high monetary costs (/spl sim/$500,000/patient) and the ever increasing number of total joint replacements being performed on an aging US population mark this disease as high priority for the development of new interventional strategies. We are designing MEMs-based sensors for a series of bacterial metabolites from both Gram-positive and Gram-negative pathogens that are associated with quorum sensing and other early events in biofilm formation. The detection of these virulence factors will initiate a metered release of the appropriate antibacterial compound contained within implant-embedded reservoirs. The therapeutic dosing will itself be monitored by sensors to ensure adequate drug delivery and all functions will be stored and recoverable via telemetry.