以前列腺特异性抗原(PSA)和前列腺特异性抗体(anti—PSA)为生物模型分子,采用电沉积技术和共价键合作用,研制了新型高灵敏电流型免疫传感器.利用具有良好导电性和热稳定性的新型有机材料[苝四甲酸二酐(PTCDA)衍生物,简写为PTC-NH2]膜具有的多孔结构,该膜可与电沉积制得的冰晶状普鲁士蓝(PB)颗粒进行层层组装镶嵌,形成多层稳定的有机-无机氧化还原复合膜以增加PB的固定量和稳定性,从而提高电极的电流响应信号;同时,通过复合膜表面丰富的氨基吸附大量纳米金以增加抗体的固定量,从而提高免疫传感器的灵敏度.利用扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)对PTC-NH2膜的形貌和结构进行表征,通过循环伏安法考察了电极修饰过程的电化学特性,详细研究了该免疫传感器的性能.该免疫电极对前列腺特异性抗原检测的线性范围为0.5~16.0ng/mL,相关系数为0.985,检测限为0.02ng/mL.实验结果表明,利用该方法制备的免疫传感器具有灵敏度高、稳定性和选择性好等优点.
A new highly sensitive amperometric immunosensor for the detection of prostate specific antigen (PSA) has been constructed by means of covalent bonding to immobilize prostate specific antibody (anti-PSA) on multilayer organic-inorganic redox-active composite film/gold nanoparticle (nano-Au) modified glassy carbon electrode surface. The morphologies of the composite films were studied by means of scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) analysis was used to characterize the chemical composition in the PTC-NH2 compound. The preparation procedure of the immunosensor was further investigated by cyclic voltammetry (CV). In addition, the performance and influencing factors of the resulting immunosensor were studied in detail. Under optimal conditions, the resulting immunosensor displayed a high sensitivity for the detection of PSA, and responsed to the PSA concentration in the range from 0.5 to 16 ng/mL (R=0.985) with a detection limit of 0.02 ng/mL. Moreover, the immunosensor exhibited high sensitivity, long-term stability and good selectivity.