Self-Propelled, Phage-Based Magnetoelastic Biosentinels for Detection of Pathogens in Liquid

This paper presents the concept of self-propelled magnetoelastic (ME) biosentinels that seek out and capture pathogenic bacteria in stagnant liquids. These biosentinels are composed of a free-standing, asymmetric-shaped ME resonator coated with a filamentous landscape phage that specifically binds with a pathogen of interest. When a time-varying magnetic pulse is applied, the ME biosentinels can be placed into mechanical resonance by magnetostriction. The resultant asymmetric vibration then generates a net force on the surroundings and hence generates autonomous motion in the liquid. As soon as the biosentinels find and bind with the target pathogen through the phage-based biomolecular recognition, a change in the biosentinel's resonant frequency occurs, and thereby the presence of the target pathogen can be detected. In order to actuate the ME biosentinels into mechanical resonance of a desired mode, modal analysis using the three-dimensional finite element method was performed. In addition, the design of a magnetic chamber that can control the orientation and/or translation of a biosentinel is discussed.