Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA 19104, USA.
Analyst. 2013 Nov 7;138(21):6365-71. doi: 10.1039/c3an01353g. Epub 2013 Sep 13.
A dual mode electrochemical piezoelectric-excited millimeter cantilever (ePEMC) sensor is reported for simultaneous in-liquid biochemical sensing. The ePEMC incorporates mass-sensing measurement of dynamic-mode cantilevers with electrochemical impedance spectroscopy (EIS) commonly employed for transduction in sensitive electrochemical biosensors. Such an integrated design allows for simultaneous and continuous measurement of resonant frequency shift (Δf) and charge transfer resistance (RCT) as a target analyte binds to the sensor gold surface (0.5 mm(2)) via electromechanical and electrochemical impedance spectroscopy, respectively. The properties of ePEMC are demonstrated in three experiments: (1) resonant frequency response to electrochemically-deposited metal thin-films, (2) resonant frequency response to adsorption of thiolated ssDNA and model proteins with subsequent EIS sensing, and (3) simultaneous resonant frequency and charge transfer resistance response to model chemisorption of a short-chain thiol molecule, mercaptohexanol. Adsorption of all model binding analytes caused decrease in sensor resonant frequency and increase in charge transfer resistance. Comparison of sensor response to binding of protein and thiol molecules showed the two simultaneously transduced signals were proportional and showed the same kinetics.
一种双模电化学压电激励毫米悬臂梁（ePEMC）传感器被报道用于同时进行液体中的生化传感。ePEMC 将动态模式悬臂梁的质量感应测量与电化学阻抗谱（EIS）结合在一起，EIS 通常用于灵敏电化学生物传感器的转换。这种集成设计允许通过机电和电化学阻抗谱分别同时连续测量共振频率偏移（Δf）和电荷转移电阻（RCT），因为目标分析物通过电机械和电化学阻抗谱结合到传感器金表面（0.5mm²）。ePEMC 的特性通过三个实验进行了证明：（1）电化学沉积金属薄膜对共振频率的响应，（2）巯基化 ssDNA 和模型蛋白吸附对共振频率的响应，以及随后的 EIS 传感，和（3）短链硫醇分子化学吸附的同时共振频率和电荷转移电阻响应，巯基己醇。所有模型结合分析物的吸附都会导致传感器共振频率降低和电荷转移电阻增加。对蛋白质和硫醇分子结合的传感器响应的比较表明，两个同时转换的信号是成比例的，并且表现出相同的动力学。
