The Fabrication Of Carbon Micro/Nano Structures Induced By Pyrolysis Of Suspended Structures And The Application In Enzyme-free Glucose Sensors

The concentration of glucose can be used to measure the metabolic degree of the human body and is also a significant healthy index for people.Quantitatively measurement of glucose content is of great importance in the fields of biochemistry,food analysis and clinical chemistry.Carbon microelectromechanical system technology which combines photolithography and pyrolysis processes is an effective and low-cost method for fabrication of carbon structures with wide electrochemical stability windows,good biocompatibility and electrical conductivity.The carbon micro/nano structures with large effective surface area have the advantages of shorting electron diffusion distance,and showing great potential in energy storage devices and biosensors.In this study,new carbon micro/nano structures with porous inner structures induced by the thermal stress produced in pyrolysis of suspended photoresist micro/nano structures were prepared.Enzyme-free glucose sensor was then prepared by integrating copper oxide film on the surface of carbon micro/nano structures,and its electrochemical performances were tested and optimized.The main contents are as follows:Firstly,photoresist microstructure arrays were prepared by photolithography process on stainless steel substrate through optimizing the exposure parameters.On the basis,suspended photoresist microstructures were fabricated by prolonging the exposure time,and the effect of exposure time on the suspended part of structures was discussed.It showed that the width of the suspended structures increased with the extension of the exposure time until reach to fully suspended.The suspended photoresist micro/nano structure arrays were prepared by oxygen plasma etching of microstructures,and the influence of steel substrate to the morphology of photoresist micro/nano structures during etching process was studied.With the increase of etching time,the depth of the photoresist micro/nano structures became deepen.The outer surface of micro/nano structures on stainless steel substrate became porous.Secondly,the mechanism of suspended photoresist micro/nano structures turned to carbon micro/nano structures during pyrolysis was studied.The influence of the width of suspended structures on the formation of carbon micro/nano structures was analyzed.It is probably caused by the thermal stress of suspended parts of structures during pyrolysis which prevented the collapse of carbon micro/nano structures.The compositions of carbon microstructures and carbon micro/nano structures were analyzed through Raman spectroscopy.The carbon structures have similar ingredients of mixture of disordered graphite and amorphous carbon.Finally,enzyme-free glucose sensors were fabricated by integrating of copper oxide film on the surface of carbon micro/nano structures through magnetron sputtering and high-temperature oxidation processes.The effects of copper oxide film thickness on the morphology of integrated structures and the performance of enzyme-free glucose sensor were studied.The electrochemical performances of the sensor were evaluated and the best working potential and electrolyte concentration were optimized.The anti-interference properties,repeatability and stability of the enzyme-free glucose sensor were also analyzed.The results showed that the fabricated enzyme-free glucose sensor has high sensitivity(1037.5?A?m M^-1?cm^-2),fast response speed(<3 s),excellent selectivity against interfering substances and good stability.