Wireless surface-scanning ME biosensors system for bacterial detection on fresh produce

This paper investigates the use of wireless, magnetoelastic (ME) biosensors for the surface-scanning detection of Salmonella Typhimurium on fresh produce (eggs, spinach leaves, tomatoes, etc.). The ME biosensor consists of a ME resonator as the sensor platform and E2 phage as the bio-recognition element. The E2 phage is genetically engineered to specifically bind with Salmonella Typhimurium. The ME biosensor is actuated into resonance by an externally applied magnetic field. A microfabricated planar coil was used to measure the resonant frequencies of multiple ME biosensors. The resonant frequency of the biosensors before and after the exposure to the spiked fresh produce was measured. When the Salmonella cells bind with the ME biosensors, the mass of the resonator increases, resulting in a decrease in the sensor´s resonant frequency. Real time, in-situ bacteria detection on fresh produce surfaces was demonstrated and compared with previous detection results.