Characterization of phage-coupled magnetoelastic micro-particles for the detection of Bacillus anthracis Sterne spores

A microfabricated magnetoelastic sensor immobilized with specific phage for the detection of Bacillus anthracis spores is presented. This micro-sensor can detect response signal remotely through magnetic field, enabling the in-situ measurement of target pathogens in aqueous environment. The sensor´s surface was modified by selected phage which provides the binding ability to B. anthracis spores. When exposed to B. anthracis spore solution, the resonant frequency of the sensor decreased due to the accumulated spore attachment on the surface. Sensors with dimensions of 200 times 40 times 4 mum were employed in the tests of increasing concentrations (10² to 10⁸ cfu/ml) of B. anthracis spores. A detection limit of 10² cfu/ml, and a sensitivity of 13.1 kHz/decade, were observed. Scanning electron microscopy (SEM) photographs demonstrated binding of target analytes to biosensors compared to controls.