石墨烯/SU-8复合导电光刻胶的制备及传感应用

Preparation and Sensing Application of Graphene/SU-8 Composite Conductive Photoresist

将导电导热性石墨烯(GR)引入光刻胶SU-8中,制备了具有导电性的复合光刻胶.采用超景深显微镜和万用表表征了石墨烯在复合光刻胶中的分散性及复合光刻胶的导电性.通过光刻法将设计的图案转移到氧化铟锡(ITO)玻璃表面制备了一种新型的GR/SU-8图案化电极元件.进一步在GR/SU-8/ITO表面电化学原位还原Cu NPs,制备了一种新型无酶传感器.实验结果表明,该传感器具有优异的电子转移性能,在1～10 mmol/L浓度范围内对过氧化氢具有良好的响应(R2=0. 999),同时稳定性优异,15 d后电流响应仍可保持90%以上,表明该导电光刻胶可用于电化学传感领域.

It was proposed to introduce graphene(GR) with electrical and thermal conductivity into the photoresist SU-8 to prepare a conductive composite photoresist. The ultra-depth microscope and multimeter were used to investigate the dispersion and the conductivity of the composite photoresist,respectively. The results show that the composite photoresist is conductive when the mass fraction of graphene reaches 3%,and the dispersion of graphene is relatively uniform. Subsequently,a novel GR/SU-8 patterned electrode(GR/SU-8/ITO) with the designed pattern was prepared by photolithography on ITO glass surface. The composite conductive photoresist with 4% GR forms a conductive path with the ITO electrode,which increases the specific surface area of the electrode. After 40 cycles of cyclic voltammetry scanning,the redox current of the composite electrode was increased and the electrode performance was further improved. Finally,a hydrogen peroxide-free enzyme sensor was prepared on the surface of composite GR/SU-8/ITO electrode by electrochemical in situ reduction of copper nanoparticles. The excellent electron transfer ability of the electrode was verified by this simple enzyme-free sensing system. The prepared sensor has good linearity detection for hydrogen peroxide in the range of 1-20 mmol/L(R2= 0. 999). The stability of the obtained biosensor is excellent because the current response can still be maintained above 90% after 15 d. At the same time,the obtained sensor also has good selectivity and anti-interference which reflected in the nearly same current response to hydrogen peroxide in the presence of various interferents. In conclusion,the above results prove the application of the conductive photoresist in the field of electrochemistry. It is believed that the composite non-enzymatic electrochemical sensor has great application in point of care in the future.