Development of a novel electrochemical imaging system for high spatio-temporal resolution imaging
摘要：INTRODUCTION Electrochemical imaging using a multi-electrode array has used for the various bio-sample evaluations,such as metabolic activity of the cell spheroids,and a neurotransmitter release activity in a rat brain slice,etc. For theses evaluation in a smaller area of a biological sample,a higher density electrode array is required. However,conventional arrays need the presence of connecting lines between the voltage supplier and individual electrodes,which severely limits the resolution of the resulting electrochemical image. To overcome this problem,we have employed a closed bipolar electrode（cBPE） with electrochemiluminescence（ECL） detecting system as a new platform for high spatio-temporal imaging（Fig. 1 A）,and demonstrated its abilities for chemical imaging. 1 METHODS A cBPE array of gold electrodes was fabricated by electroless plating in 8.0 μm diameter pores of a track etched membrane using 50 mM HAuCl4 and 50 mM NaBH4. The cBPE array was put between the sample cell and the detection cell. An Ag/AgCl reference electrode was placed in the sample cell,and the Pt driving electrodes（surface area:2 × 4 cm） in the sample cell and detection cell were connected to the working electrode and counter electrode terminals of the potentiostat,respectively. The detection cell was filled with a solution of 10 mM of [Ru（bpy）3]Cl2 and 100 mM of tripropylamine containing 0.1 M KCl. 500 μL of a 50 mM K3[Fe（CN）6] solution containing 0.1 M KCl was injected into a 0.1 M KCl solution in the sample cell,while applying the detecting voltage（-1.1 V） to the driving electrode and the resulting ECL from the bottom side of the detecting cell was captured with the CCD camera. The exposure time and optical sensing gain of the CCD camera were set as 0.1 s and 200,respectively. RESULTS A cBPE array of gold electrodes with 8.0 μm in diameter and 35 μm pitches in average was successfully fabricated by electroless plating. Using this cBPE array,a series of time-lapse images of spreading of [Fe（CN）6]3-on an injection of the 50 mM K3[Fe（CN）6] solution on the cBPE array was obtained as ECL signal derived from the oxidation of [Ru（bpy）2]Cl2 and tripropylamine coupled with the reduction of [Fe（CN）6]3-（Fig. 1 B）. CONCLUSIONS In this research,we developed a novel imaging system using a c BPE array and ECL signal,and demonstrated its abilities for high spatio-temporal chemical imaging. In future,this imaging system will be applied for various evaluations including bio-imaging of small area of the biological sample.
中国化学会第十二届全国微全分析系统学术会议、第七届全国微纳尺度生物分离分析学术会议、第七届国际微流控学学术论坛、The 11th International Symposium on Microchemistry and Microsystems