Amorphous magnetoelastic sensors for the detection of biological agents

Freestanding amorphous magnetoelastic (ME) biosensors were fabricated by two ways. One type with larger size, 2000 × 400 × 15 μm, 1000 × 200 × 15 μm and 500 × 100 × 15 μm, was made from an ME Fe40Ni38Mo4B18 ribbon, the other with smaller size 200 × 40 × 4 μm was manufactured by dual beam sputtering and non-traditional microelectronic fabrication techniques. Both platforms were immobilized with JRB7 phage and were developed for the real-time in vitro detection of Bacillus anthracis spores. The experimental results show that the measured sensitivity of the ME sensors agrees with theoretical predictions and the specificity of ME sensors coated with JRB7 phage for B. anthracis spore species is excellent. The 200 × 40 × 4 μm biosensor was found to have a detection limit of 102 cfu/ml and sensitivity of 13.1 kHz/decade.