Sánchez Samuel, Pumera Martin, Fàbregas Esteve
GSB, Department of Chemistry, Autonomous University of Barcelona, Bellaterra, Spain.
Biosens Bioelectron. 2007 Oct 31;23(3):332-40. doi: 10.1016/j.bios.2007.04.021. Epub 2007 May 6.
The simple and efficient method for preparing sensitive carbon nanotube/polysulfone/RIgG immunocomposite is described. The membrane of the modified disposable screen-printed electrochemical immunosensor is based on phase inversion method. Carbon nanotube/polysulfone membrane acts both as reservoir of immunological material and transducer while offering high surface area, high toughness and mechanical flexibility. The comparison with graphite/polysulfone/RIgG immunosensors shows a much higher sensitivity for those prepared with carbon nanotubes coupled with polysulfone (PSf). The membrane was characterized by scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), laser profilometer and by atomic force microscopy (AFM). The purity of the materials was evaluated by thermogravimetric analysis (TGA). The roughness value is doubled when MWCNTs are used instead of graphite into the PSf membranes and the incorporation of antibodies enhances the dispersion of the carbon with the polymeric membrane reducing the roughness in all cases. This biosensor was based on the competitive assay between free and labelled anti-RIgG for the available binding sites of immobilized rabbit IgG (RIgG). The RIgG was incorporated into the polysulfone membrane by a phase inversion method. Horse radish peroxidase (HRP) enzyme was used as label and hydroquinone as mediator. The detection limit for competitive assay was determined to be 1.66 microg/ml. the linear range of anti-RIgG from 2 to 5 microg/ml and the C(50) was found at 3.56 microg/ml. The sensitivity is five times higher for MWCNT than for graphite electrodes, showing lower unspecific adsorption.
描述了一种制备灵敏的碳纳米管/聚砜/兔免疫球蛋白G（RIgG）免疫复合物的简单高效方法。改性一次性丝网印刷电化学免疫传感器的膜基于相转化法。碳纳米管/聚砜膜既作为免疫材料的储存器又作为换能器，同时具有高表面积、高韧性和机械柔韧性。与石墨/聚砜/RIgG免疫传感器的比较表明，用碳纳米管与聚砜（PSf）耦合制备的免疫传感器具有更高的灵敏度。通过扫描电子显微镜/能量色散X射线分析（SEM/EDX）、激光轮廓仪和原子力显微镜（AFM）对膜进行了表征。通过热重分析（TGA）评估了材料的纯度。当在PSf膜中使用多壁碳纳米管（MWCNTs）代替石墨时，粗糙度值加倍，并且抗体的掺入增强了碳与聚合物膜的分散性，在所有情况下都降低了粗糙度。这种生物传感器基于游离和标记的抗RIgG对固定化兔IgG（RIgG）可用结合位点的竞争测定。通过相转化法将RIgG掺入聚砜膜中。使用辣根过氧化物酶（HRP）作为标记物，对苯二酚作为媒介物。竞争测定的检测限确定为1.66微克/毫升。抗RIgG的线性范围为2至5微克/毫升，半数抑制浓度（C(50)）为3.56微克/毫升。MWCNT的灵敏度比石墨电极高五倍，显示出较低的非特异性吸附。
