多孔硅适配子生物传感器的电化学研究

Electrochemical study of aptamer biosensor on nano-porous silicon

构建1种用于快速检测四环素的新型电化学纳米多孔硅（PS）生物传感器。通过脉冲腐蚀法制得多孔硅基片,将适配子固定于其上,这种四环素适配子能够特异性识别四环素分子,并引起阻抗值的变化。利用电化学交流阻抗法比较固定适配子前后硅片表面阻抗值的变化,以及在体系中加入不同浓度四环素后阻抗谱的变化。选择1个合适的等效电路对测得的阻抗数据进行拟合,获得了四环素浓度与阻抗值的变化规律。传感器的线性检测范围为2.079~62.37 nmol/L,检测限为2.079 7 nmol/L。

A new electrochemical nanobiosensor was prepared based on porous silicon（PS） for rapid detection of tetracycline.Nano-porous silicon was fabricated using an electrochemical etching process.Aptamers were immobilized on the PS surface.The specific binding of the tetracycline to its aptamer leaded to a decrease in impedance.Electrochemical impedance spectroscopy（EIS） was used to compare impedance changes of aptamer immobilized with free PS.The corresponding impedance spectra（Nyquist plots） were obtained when serial concentrations of tetracycline were added into the system.An equivalent electrical circuit was used to fit the obtained impedance data.The results indicated that the decrease of the impedance was proportional to the concentration of the tetracycline.The linear range of the sensor was 2.079 nmol/L to 62.37 nmol/L and the sensitivity was 2.079 7 nmol/L.