Kim Gi Ho, Rand A Garth, Letcher Stephen V
Department of Physics, University of Rhode Island, Kingston, RI 02881, USA.
Biosens Bioelectron. 2003 Jan;18(1):83-9. doi: 10.1016/s0956-5663(02)00142-2.
This study investigated the impedance characteristics of a 5 MHz quartz crystal resonator oscillating in a thickness-shear mode for utilization as a biosensor. An impedance analyzer measured the impedance of the quartz crystal, which determined all mechanical properties of the oscillating quartz and its immediate environment. In this study, the impedance behavior of the oscillating crystal was characterized in air, in potassium phosphate buffer solution, and with immobilization of antibodies using protein-A. The potassium phosphate buffer behaved like a Newtonian liquid. The series resonance frequency shifted down about 900 Hz on contact with the buffer. An immobilized-antibody layer on the quartz surface behaved like a rigid mass when immersed in the buffer solution. The impedance curve following immobilization of antibodies was shifted down in frequency by about 200 Hz compared with its value when the bare crystal was immersed in the buffer solution.
本研究调查了以厚度剪切模式振荡的5兆赫兹石英晶体谐振器用作生物传感器时的阻抗特性。阻抗分析仪测量石英晶体的阻抗，该阻抗决定了振荡石英及其周围环境的所有机械性能。在本研究中，振荡晶体的阻抗行为在空气中、磷酸钾缓冲溶液中以及使用蛋白A固定抗体的情况下进行了表征。磷酸钾缓冲液表现得像牛顿流体。与缓冲液接触时，串联谐振频率下移约900赫兹。石英表面固定的抗体层在浸入缓冲溶液时表现得像一个刚性质量块。与裸晶体浸入缓冲溶液时相比，固定抗体后的阻抗曲线在频率上下移了约200赫兹。
