农业工程学报Issue(16)：182-189,8.DOI:10.3969/j.issn.1002-6819.2013.16.023
自参考离子选择性电极技术应用中的微电极制备及测试
Test and preparation of microelectrode in applications of self-referencing ion electrode technique
摘要
Abstract
An self-referencing ion electrode technique provides a novel electrophysiological tool which can non-invasively measure the dynamic influxes and effluxes of ions from cells and organs in vivo. In fact, the foundation of this technique is the fabrication and performance test of an ion selective microelectrode (ISME). In this paper, the K+ISMEs with good performances were obtained. We elaborated the procedure to prepare the glass micropipettes and to fill the pipettes with internal filling solution and liquid ion exchangers (LIX) of potassium, and then estimated the performance of these ion selective microelectrodes. Measurement of tip size, measuring method of resistance, testing of detection range, Nernstian slope, and response time, were described in detail. Ion selective microelectrodes were calibrated before and after experiments using two or more different kinds of concentrations of K+within its operating range based directly on the potentiometric analysis. The procedure for ion selective microelectrodes fabrication is strict. The electrodes (the diameter of the apex of the tip was 1~9μm) were pulled from non-filamented borosilicate glass capillaries (TW150-3, World Precision Instruments, USA) on a vertical micropipette puller (WD-2, Chengdu Instrument Factory, Chengdu), oven dried, and then silanized by injecting 2 mL of 5%dimethyldichlorosilane (Sinopharm Chemcial Reagent Co. Ltd, Beijing) with n-hexane as the solvent in a glass preparation chamber at 150℃. Afterwards, dried and cooled electrode blanks were back-filled with a 100 mmol/L KCl solution. Immediately after back-filling, the microelectrode tips were front-filled with liquid ion exchangers of potassium (60031, Sigma, USA). Furthermore, some of the factors that affect the performance of the microelectrode in the preparation were discussed in detail. The ISME’s resistance reaches to 108~109Ωfilling with LIX (length is 150~210μm), much higher than that which occurs without LIX. The detection range obtained by the K+ISME is linear within a wide range of 0.01~500 mM KCl solutions with the slope of 53.095 mV per decade, and R2 of 0.9998, which means the K+ISME response is in accordance with the Nernst equation. Besides the attainable Nernstian response range, the response time t95%, from the beginning of that ISE immersed into the K+ion standard solutions with two concentrations, 1 and 100 mmol/L KCl, with 8 assays each concentration, to the 95%of stable potentials, is less than 1s. These measurements were made at room temperature (20~25℃). The results show that the fabrication of the ion selective glass microelectrodes is the key to obtaining the high performance of the microelectrode. The parameters of microelectrodes, i.e. tip size, resistance and response time, etc. are very important in practical application. This work can provide a reference basis for the fabrication and application in SIET of ion selective microelectrodes. Moreover, the standardized fabrication is the precondition to measure the dynamic influxes and effluxes of ions from cells and organs in vivo using the SIET.关键词
无损检测/微电极/测试/硅烷化/能斯特斜率Key words
non-distructive examination/microelectrodes/test/silanization/Nernstian slope分类
信息技术与安全科学引用本文复制引用
薛琳,赵东杰,侯佩臣,王晓冬,王媛,王成,王忠义,黄岚..自参考离子选择性电极技术应用中的微电极制备及测试[J].农业工程学报,2013,(16):182-189,8.基金项目
国家重大科学仪器设备开发专项（2011YQ080052）；中央高校基本科研业务费专项资金（2013YJ008）。 （）
