Fabrication And Properties Of Gold Microarray Electrode Based On DMD Lithography And Electrodeposition

Electrochemical Biosensor Array（EBA）is widely used due to its high selectivity,high sensitivity,and fast analysis speed.As a transducer element,the performance of microarray electrodes plays a key role in the performance of electrochemical sensors.The construction of high-performance electrode materials has become a current research hotspot.In this study,a simple method with the Digital Micro-mirror Devices（DMD）based multi-step lithography（DMSL）and electrochemical deposition was proposed.Through the combination of dose modulation,flexible pattern generation of DMD,and high-resolution step movement of piezoelectrical stage（PZS）,the method has demonstrated this method capable of precisely controlling both the structure and the location of the electrochemical deposition nanoparticle clusters.Next,Au was electrochemically deposited on the template.The uniform Au microarray electrodes（MAE）were prepared.The specific research content is divided into the following parts:（1）By designing and controlling the surface area and the shape of the mask,a variety of micro-structures with the surface area and shape of the structural unit have been successfully prepared.Using ultraviolet positive photoresist as the photosensitive medium and DMD maskless lithography technology,square,round,hexagonal and triangular shapes were prepared on indium tin oxide（ITO）conductive glass coated with photoresist of uniform thickness.These micro-structures were periodic microarray structure template.According to the same processing method,aperiodic micro-structure templates with random arrangement of ellipses,hexagons and pentagram were prepared.（2）Combined with electrochemical deposition technology,gold was deposited on the prepared template,and the corresponding gold micro-structure electrode was prepared.The microstructure of the electrode was characterized,which proved the successful preparation of the electrode.The effects of the period,surface area and shape of each gold micro structure electrode on the redox current were studied by electrochemical measurement.It is found that with the same total surface area,the electrochemical signal of Au microarray with the same shape first increases and then decreases with the increase of the surface area of structural units,and the redox peak is the largest when the surface area is 1.7×10^-5 cm².The electrode with the same unit surface area exhibits the same electrochemical signal,which is independent of the shape and period.（3）Using the optimal microstructure electrode obtained by experiments,the performance of the electrode was further studied by related electrochemical tests.The experimental results show that the prepared electrode has good electrochemical characteristics such as strong interference ability and good stability,which provides a feasible operation scheme for the preparation of biosensor array.（4）The SERS substrate was prepared by the combination of the two techniques（the same method as above）.By adjusting the deposition time in the reaction process,the nucleation and growth process of gold nanoparticles were flexibly controlled,so as to control the morphology of gold nanoparticles.The experimental results show that the Raman signal is the best when the electrolysis time is 15 minutes.At this time,the dendrites are numerous and dense,which increases the surface area and roughness to a certain extent,thus a large number of"hot spots"are produced.The feasibility of SERS substrate prepared by this method is verified.