Summary

薄膜铂金宏观和微电极的电化学粗加工

Published: June 30, 2019
doi:

Summary

该协议演示了一种在晶粒边界上不优先溶解的薄膜铂电极电化学粗加工方法。介绍了循环伏抗和阻抗光谱的电化学技术,以表征这些电极表面。

Abstract

该协议演示了一种在金属晶粒边界上不优先溶解薄膜铂电极电化学粗加工的方法。该方法得到一种无裂纹的薄膜大电极表面,有源表面积增加40倍。在标准电化学表征实验室中,粗加工很容易进行,并引入电压脉冲的应用,随后在高氯酸溶液中扩展应用还原电压。该协议包括宏观尺度(1.2 mm直径)和微尺度(20微米直径)铂盘电极表面的化学和电化学制备,对电极表面进行粗加工,并描述表面粗加工对电极有源表面积。这种电化学表征包括循环伏抗和阻抗光谱,并针对宏电极和微电极进行了演示。粗加工可增加电极有源表面积,降低电极阻抗,增加相同几何形状的氮化钛电极的铂电荷注入极限,并改进基板,使其附着电化学沉积薄膜.

Introduction

近五十年前,首次观测到表面增强拉曼光谱(SERS)发生在电化学粗化银1。金属箔的电化学粗加工今天仍然具有吸引力,因为它比其他粗加工方法2,3的简单性,它在许多应用中的有用性,如改进aptamer传感器4,改善神经探针5,提高金属基板6的附着力。许多散装金属电化学粗加工方法存在1、5、7、8、9、10。然而,直到最近,还没有关于电化学粗加工应用于薄(百纳米厚)金属薄膜的报告,尽管微制薄膜金属电极在很多领域普遍存在。

建立的方法粗糙厚铂(Pt)电极5,8分层薄膜Pt电极6。通过调节粗加工过程的频率和用于粗加工的电解质,Ivanovskaya 等人演示了 Pt 薄膜粗加工,无需分层。该出版物侧重于使用这种新方法增加微制神经探头上铂记录和刺激电极的表面面积。该电极的粗加工性能提高了记录和刺激性能,提高了电化学沉积膜的附着力,提高了生物传感器的灵敏度6.但是,这种方法还可能改进微制电极阵列的表面清洁,并增强薄膜电极用于其他传感器应用(例如 aptasensor)的能力。

在以下协议中描述了粗制薄膜宏电极(1.2 mm直径)和微电极(20μm直径)的方法。这包括为粗加工而制备电极表面,以及如何描述电极的粗糙度。介绍了这些步骤,并介绍了如何针对其他电极几何形状优化粗加工过程以及确保电极无损粗加工的最重要因素。

Protocol

注意:请在使用前查阅所有相关的安全数据表 (SDS)。本议定书中使用的几种化学品在高浓度下使用时具有剧毒、致癌、氧化和爆炸性。与散装材料相比,纳米材料可能具有额外的危害。执行此协议时,请使用所有适当的安全实践,包括使用工程控制(烟罩)和个人防护设备(安全眼镜、手套、实验室外套、全长裤子、闭趾鞋)。 1. 在初始表征和表面粗加工之前清洁 Pt 电极 用实验…

Representative Results

图2显示了对宏电极和微电极进行粗加工的电压应用的示意图。光学显微镜可用于可视化粗化宏电极(图3)或微电极(图4)外观的差异。此外,使用阻抗光谱和循环伏抗法对Pt表面的电化学表征可以很容易地显示粗化宏电极(图1)和微电极(图1)的活性表面积增加(图 5.<…

Discussion

薄膜大电极和微电极的电化学粗加工可以通过氧化还原脉冲进行。这种简单的方法确实需要几个关键元素来无损粗糙薄膜电极。与铝箔不同,如果参数没有正确选择,薄膜的粗加工可能导致样品破坏。粗加工过程的关键参数是脉冲振幅、持续时间和频率。此外,确保电极清洁度和在手术前的高氯酸纯度对于防止电极损坏至关重要。微加工过程中存在有机物或污染物,会通过腐蚀或分层造成电极的破坏。…

Divulgaciones

The authors have nothing to disclose.

Acknowledgements

作者感谢劳伦斯·利弗莫尔国家实验室生物工程中心在编写本手稿期间给予的支持。Loren Frank 教授因与团队合作,使上述工作中讨论的薄膜 Pt 微阵列的制造和设计得以进行,这一合作令人欣然接受。这项工作由美国能源部主持,由劳伦斯利弗莫尔国家实验室根据DE-AC52-07NA27344合同进行,并由实验室定向研发奖16-ERD-035资助。LLNL IM 版本 LLNL-JRNL-762701。

Materials

Acetone Fisher Scientific, Sigma Aldrich or similar n/a Laboratory grade
EC-Lab Software Bio-Logic Science Instruments n/a For instrument control and data analysis
Leakless Silver/Silver Chloride Reference eDAQ Company, Australia ET069-1 Free from chloride anion contamination
(or other type of chloride free electrode e.g. Mercury sulfate electrode)
Mercury Sulfate & Acid Electrode Kit  Koslow, Scientific Testing Instruments 5100A glass, 9mm version
Milipore DI water MilliporeSigma n/a Certified resistivity of 18.2 MΩ.cm (at 25°C) 
Perchloric acid, 99.9985% Sigma Aldrich 311421 High Purity
Phosphate-buffered saline Teknova P4007 10mM PBS with 100mM NaCl, pH 7
or similar product from elsewhere
Platinum Wire Auxiliary Electrode (7.5 cm) BASi MW-1032 Counter electrode
Pt macroelectrodes Lawrence Livermore National Laboratory n/a 1.2 mm diameter, 250 nm thick Pt disc electrodes insulated in polyimide. More information in Reference 9.
Pt microelectrode arrays Lawrence Livermore National Laboratory n/a 20 µm diameter 250 nM thick Pt disc electrodes insulated in polyimide. More information in Reference 9.
Sulfuric acid, 99.999% Sigma Aldrich 339741 High Purity
UV & Ozone Dry Stripper Samco UV-1 for cleaning electrodes
VersaSTAT 4 Potentiostat AMETEK, Inc. n/a Good time resolution for pulsing tests
VersaStudio Software AMETEK, Inc. n/a For instrument control
VMP-200 Potentiostat  Bio-Logic Science Instruments n/a Low current resolution option is preferable for measurements with microelectrodes

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Ivanovskaya, A. N., Belle, A. M., Yorita, A., Qian, F., Chen, S., Tooker, A., Lozada, R. G., Dahlquist, D., Tolosa, V. Electrochemical Roughening of Thin-Film Platinum Macro and Microelectrodes. J. Vis. Exp. (148), e59553, doi:10.3791/59553 (2019).

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