Detection of Staphylococcus Aureus in Different Liquid Mediums Using Wireless Magnetoelastic Sensor

The magnetoelastic Staphylococcus aureus (S. aureus) wireless sensor was fabricated to detect S. aureus in different liquid mediums. Approximately 0.2 mL bacterial solution with proper concentration was taken into testing cuvette containing 2 mL of liquid medium, and the magnetoelastic sensor resonance frequency changed with the growth of bacteria. By changing the concentration of beef extract and peptone, sensor had the most frequency response in culture medium (CM) 2-2 incubated with 2 × 105 cells mL−1S. aureus. The results indicated that the sensor can be used to determine S. aureus in the concentrations range of 3 × 103–2 × 107 cells mL−1 in CM and 104–107 cells mL−1 in milk, with a detection limit of 103 and 104 cells mL−1, respectively. The sensor frequency shift was correlated to the logarithmic value of the concentration of S. aureus. The coefficient was 0.98 in milk and 0.99 in CM.