The Research On The Integration Of The Magnetostrictive Biosensor Technology

With the increasing of the demand for the rapid and accurate detection of pathogenic microorganisms in food safety,environmental protection,clinical diagnosis and other fields,the development of the biological detection technology which is fast,simple,portable and can be detected in situ has become an international research focus.Magnetostrictive biosensor is a wireless passive resonant sensor and is suitable for the direct detection in liquid,which determines that magnetostrictive biosensor is superior to other biological detection techniques in the bacterial detection.At present,the traditional detection method is that a spiral coil is used to drive and detect sensor.Although this method can obtain good detection signal,this coil with 3D structure is hardly integrated with microfluidic systems with planar structure.As the spiral coil is hardly made by MEMS process,it is difficult to achieve high-precision,low-cost mass production.Thus,the detection technology of the spiral coil hinder the development of the integration and miniaturization of magnetostrictive sensors.The planar coil with 2D structure which can be prepared by MEMS process has the advantage of easy integration,but at present there is no research on the integration of the magnetostrictive sensors with the planar coils.In view of the above background,this paper designs and develops an integrated detection module based on magnetostrictive sensor,which includes magnetostrictive sensor,planar coil,microfluidic system.The key technology of this module is to optimize the detection of the magnetostrictive sensors driven by planar coils.In this paper,the planar coil is modeled and analyzed from the aspects of excitation and detection to enhance the excitation signal and the detection signal of the planar coil so as to obtain the optimized design of the planar coil.On this basis,a lab-on-a-chip type integrated magnetostrictive detection module is designed and prepared in this paper.The planar coil is prepared by MEMS process and the microfluidic structure is prepared by casting method.The entire module can be accomplished by a simple superposition of the planar coil layer and the microfluidic structure layer.In order to verify the feasibility of the proposed integrated detection module,real-time,in-liquid detection of yeast cells at different concentrations was successfully performed by assembling poly-L-lysine coated magnetostrictive biosensors into the chip.The results showed that continuous decrease in the resonant frequency of the magnetostrictive biosensor was observed as yeast cells were attaching on the sensor surface.And the final change of the resonance frequency increases with the increases of the concentration of yeast solution.Real-time in situ detection of yeast cells in the liquid phase was successfully achieved by using this integrated module of the magnetostrictive sensor.The integrated module developed in this paper has broad application prospects in the field of biological bacteria detection.