新型石英晶体微天平分子键裂免疫传感器的研制

Development of a Novel Molecular Bond-Rupture Immunosensor for Quartz Crystal Microbalance

基于谐振调幅电压激励石英晶体微天平设计了一种分子键裂型生物传感系统。该传感系统通过Arduino控制数字信号发生器DDS 9854产生正弦波以激励9.98 MHz压电石英晶体。采用了自主振荡电路法和被动激励振荡法,在低振幅(2 V)下以谐振电路法测定晶体谐振频率,通过高速继电器切换到被动调幅激励电路中,经数控放大器调节不同激励电压实现谐振调幅,增大石英晶体表面的剪切动量,从而实现分子键裂。随着调幅电压的升高,晶体表面物质的动量增加,导致分子键断裂,通过谐振电路频率和调幅电压值在数分钟内可得到晶体表面物质结合强度的信息。将传感系统应用于A型金黄色葡萄球菌细胞壁蛋白(蛋白质A)和免疫球蛋白IgG体系,在调幅电压激励下会抑制二者的结合。同时,在不同激励电压下可区分蛋白质A与IgG的结合强度。

A molecular bond-rupturing biosensor system based on the resonant amplitude modulated quartz crystal microbalance excited by different voltages was designed.The sensor system uses arduino to control the digital signal generator DDS 9854,which generates sinusoidal waves to stimulate the 9.98 MHz piezoelectric quartz crystal.The autonomous oscillation circuit method and the passive excitation oscillation method are adopted.The crystal frequency was measured by a low-amplitude(2 V)resonant circuit,and then switched to a passive amplitude modulation excitation circuit through a high-speed relay.By adjusting different excitation voltages,the resonant amplitude modulation is realized,and the shear momentum on the surface of quartz crystal is increased,thus the molecular bond splitting is realized.With the increase of the amplitude modulation voltage,the displacement velocity of the material on the crystal surface increases,leading to the fracture of molecular bonds.By resonating the circuit frequency and the amplitude modulated voltage value,the information of the crystal surface bonding quality and strength can be obtained in a few minutes.By applying the sensor system to the cell wall protein(protein A)and immunoglobulin IgG,the binding of these two protein was inhibited under the excitation of amplitude modulated voltage.Meanwhile,the binding strength of protein A to IgG and BSA could be distinguished under different excitation voltages.