An Implantable Differential Sensor with Passive Wireless Interrogation for In-Situ Early Detection of Periprosthetic Joint Infection

This paper presents an implantable, passive wireless biosensor for integration with knee joint prostheses to facilitate in situ early detection of periprosthetic joint infection (PJI). The magnetoelastic (ME) transduction mechanism of the sensor enables wireless interrogation without the need of an antenna or battery. Antibodies are immobilized on the sensor to target specific types of bacteria of interest. A novel differential configuration of the ME sensor is introduced to distinguish the response to target bacteria from variations in properties of the surrounding fluid medium. A triangular sensor geometry is used to help enhance mass sensitivity. Differential sensor operation was successfully verified in vitro for bacterial detection in E. coli suspensions with different viscosities ranging between 1-5.9 cP, demonstrating effective elimination of the effect of the fluid medium.