Surface modification for realizing implantable biosensors

利用离子敏感场效应晶体管（ISFET）对抗体蛋白进行高密度、高活性的固定，对植入式免疫传感器具有重要意义。本研究采用等离子体聚合膜作为免疫抗体的载体。我们选用对硅衬底具有良好附着力的六甲基二硅氧烷（HMDS）作为有机膜的材料，采用等离子体聚合法制备有机膜。我们在有机膜表面引入SH-基团作为功能基团，通过对具有SH-基团的乙二硫醇进行辉光放电处理来灭活抗体。我们证实，疏水表面变得疏水，通过这种表面改性。改性后表面张力与水的接触角由125 °变为52 °。仅在改性膜中观察到硫的XPS信号的事实是引入SH基团的证据。半胱氨酸通过SS键共价固定在表面。的an ...更多信息 用交联半胱氨酸的NH_2-基团和抗体F_ '铰链的SH-基团与双功能试剂共价固定抗体（抗人血清白蛋白IgG）<ab>。酶免疫测定（EIA）表明，活性固定化的活化抗体密度约为10^<11>[cm^<-2>]（最接近的密度为2 × 10 ^<12>），显示出高密度的固定化。为了研究非特异性吸附的量，通过EIA类似地测量没有固定抗体的有机膜。结果表明，引入SH-基团和半胱氨酸的膜比引入NH_2-基团的膜具有更小的非特异性吸附。我们测量了这种固定化抗体的表面电位的变化引起的抗原抗体结合。在0.01 - 1 mg/ml的抗原浓度下观察到0.1 mV数量级的表面电位变化。在抗原与其他物质（牛血清）共存的情况下，我们获得了相同的结果。这一结果表明了实现免疫传感器的可能性。少

It is important for implantable immune-sensors by using ion-sensitive field-effect transistor(ISFET)to immobilize antibody-protein with high density and high activity. In this research, we use plasmapolymerized membrane for the career of inunobilized antibody. We use Hexamethyldisiloxane(HMDS), which is excellent in adhesion to silicon substrate, for the materials of organic membrane, and fabricate the membrane by plasma-polymerized method. We introduce SH-groups on the surface of organic membrane as functional group to inunobilize antibody by applying glow-discharge treatment to ethanedithiol having SH-groups. We confirm that hydrohibic surface becomes hydrophobic by this surface modification. The contact angle of the surface tension, which was 125ﾟ with water, turns 52ﾟ after modification. The fact that XPS signals of sulfur is observed only in the modificated membrane, is the evidence that SH-groups are introduced. Cysteine is covalently immobilized by SS-bond on the surface. The an … More tibody(anti-Human Serum Albrffin IgG)is covalently immobilized with crosslinking NH_2-groups of cysteine and SH-groups of antibody F_<ab>' hinge together with bifunctional reagent. The activity immobilized activated antibody density is of the order of 10^<11>[cm^<-2>](the closest density is 2X10^<12>)by enzymeimmunoassey(EIA), which shows high density immobilization. To investigate quantity of non-specific adsorption, organic membrane having no immobilized antibody is similarly measured by EIA. As a result, the membrane introduced SH-groups and Cysteine has less non-specific adsorption than that of NH_2-groups. We measure the changing of surface potential of this immobilized antibody caused by antigen-antibody binding. A surface potential change of the order of 0.1 mV is observed at the antigen concentration of 0.01 - 1 mg/ml. We attain the same result in the case that the antigen coexists with other substances(Bovine Serum). This result suggests the possibility of realizing immune-sensors. Less