The detection of Mycobacterium tuberculosis in sputum sample based on a wireless magnetoelastic-sensing device

This paper presents a real-time detection of Mycobacterium tuberculosis (M. TB) using a wireless magnetoelastic sensor. The sensor is fabricated by coating a magnetoelastic ribbon (Metglas 2826MB™) with a polyurethane protecting film. M. TB consumes the nutrients of a liquid culture medium in growing and reproducing process, which results in properties changes (viscosity, density, elasticity, ion concentration, etc.) of the culture medium, and consequently changes in the resonance frequency of the magnetoelastic sensor. Using the described technique M. TB is quantified and sensor response is proportional to logarithmic values of the M. TB concentration from 104 to 109 cells ml−1, with a detection limit of 104 cells ml−1 at a noise level of ∼10 Hz. The sensor can be used effectively for monitoring the bacterial growth and good results were obtained when used in sputum sample. The drug-resistance of isoniazid (INH) and rifampin (RFP) on M. TB growth in culture medium was evaluated based on this proposed method. The wireless nature of the presented device facilitates the aseptic operations.