Detection of salmonella on globe fruits using pulse excited magnetoelastic biosensors

Abstract

This paper describes the results of a research project to investigate magnetoelastic (ME) biosensors actuated with a pulse excitation to measure the concentration of Salmonella Typhimurium of globe fruits. The ME biosensors are based on an acoustic wave resonator platform that is a freestanding (free-free) thin ribbon of magnetostrictive material with a lengthto- width ratio of 5:1. A biorecognition probe coated on the surface of the resonator platform binds with a targeted pathogen, i.e. E2 phage that binds with S. Typhimurium. The biosensor was actuated to vibrate longitudinally such that the resonant frequency depended primarily on the length of sensor and its overall mass. A pulsed excitation and measurement system was used to actuate micron scale ME biosensors to vibrate. The biosensor responds in a ring-down manner, a damped decay of the resonance amplitude, from which the resonant frequency was measured. An increase in mass due to the binding of the target pathogen resulted in a decrease in the resonant frequency. The pulsed excitation and measurement system that was developed under this effort and the characterization of its performance on the measurement of Salmonella concentrations on globe fruits is described.