Design and Simulation of MEMS Biosensor for the Detection of Tuberculosis

Background/Objectives: This paper presents the design and simulation of MEMS microcantilever sensor for the identification of Mycobacterium tuberculosis in the given blood sample. Method/Analysis: The surface of the microcantilever is covered with TB antibodies which are specific to TB antigen 85complex. When the blood sample containing tuberculosis bacteria is placed on it, biochemical reactions occur between TB antigens and the antibodies on the surface of the microcantilever. This gives a deflection to the microcantilever from which TB can be detected. COMSOL Multi Physics is used in the design of micro cantilever. Findings: Presently the most general method for diagnosing TB is the sputum smear microscopy in which micro organisms are observed under a microscope. In some of the advanced countries culture methods are used to detect TB. At present TB identification method requires a period of 4 to72 hours and is not so accurate. Hence there is a need of MEMS sensor which offers quick and accurate method to detect Mycobacterium tuberculosis. When the patient’s blood sample is placed on the microcantilever, the antigen-antibody interaction causes it to bend and the adsorb molecules generates a surface stress on the microcantilever. This stress is created due to the interactions between the molecules and the microcantilever surface. It has been observed that the deflection of the micro cantilever is high for a length of 20μm and for a width of 5μmkeeping the other parameters constant Application/Improvements: Using this MEMS bio sensor, tuberculosis disease can be identified very accurately and speedily comparing to existing methods.