University of Cincinnati, Department of Chemistry, 312 College Dr., 404 Crosley Tower, Office# 418A Rieveschl, Cincinnati, OH 45221-0172, USA.
Analyst. 2024 Sep 9;149(18):4643-4652. doi: 10.1039/d4an00307a.
The sensitivity of zinc (Zn(II)) detection using fast-scan cyclic voltammetry (FSCV) with carbon fiber microelectrodes (CFMEs) is low compared to other neurochemicals. We have shown previously that Zn(II) plates to the surface of CFME's and we speculate that it is because of the abundance of oxide functionality on the surface. Plating reduces sensitivity over time and causes significant disruption to detection stability. This limited sensitivity and stability hinders Zn(II) detection, especially in complex matrices like the brain. To address this, we developed plasma-treated gold fiber microelectrodes (AuMEs) which enable sensitive and stable Zn(II) detection with FSCV. Typically, gold fibers are treated using corrosive acids to clean the surface and this step is important for preparing the surface for electrochemistry. Likewise, because FSCV is an adsorption-based technique, it is also important for Zn(II) to adsorb and desorb to prevent irreversible plating. Because of these requirements, careful optimization of the electrode surface was necessary to render the surface for Zn(II) adsorption yet strike a balance between attraction to the surface irreversible interactions. In this study, we employed oxygen plasma treatment to activate the gold fiber surface without inducing significant morphological changes. This treatment effectively removes the organic layer while functionalizing the surface with oxygen, enabling Zn(II) detection that is not possible on untreated gold surfaces. Our results demonstrate significantly improved Zn(II) detection sensitivity and stability on AuME compared to CFME's. Overall, this work provides an advance in our understanding of Zn(II) electrochemistry and a new tool for improved metallotransmitter detection in the brain.
使用碳纤维微电极（CFME）的快速扫描循环伏安法（FSCV）检测锌（Zn(II)）的灵敏度相对其他神经化学物质较低。我们之前已经表明，Zn(II)会在 CFME 的表面上电镀，我们推测这是因为表面上氧化物官能团的丰富性。随着时间的推移，电镀会降低灵敏度，并导致检测稳定性受到严重干扰。这种有限的灵敏度和稳定性阻碍了 Zn(II)的检测，特别是在大脑等复杂基质中。为了解决这个问题，我们开发了等离子体处理的金纤维微电极（AuME），它可以使用 FSCV 实现灵敏和稳定的 Zn(II)检测。通常，金纤维会使用腐蚀性酸进行处理，以清洁表面，这一步对于为电化学准备表面非常重要。同样，由于 FSCV 是一种基于吸附的技术，因此对于 Zn(II)的吸附和脱附也很重要，以防止不可逆的电镀。由于这些要求，需要仔细优化电极表面，以使其能够进行 Zn(II)吸附，但又要在表面的吸引力和不可逆相互作用之间取得平衡。在这项研究中，我们使用氧等离子体处理来激活金纤维表面，而不会引起明显的形态变化。这种处理有效地去除了有机层，同时用氧官能化表面，使得在未经处理的金表面上不可能进行的 Zn(II)检测成为可能。我们的结果表明，与 CFME 相比，AuME 上的 Zn(II)检测灵敏度和稳定性有了显著提高。总的来说，这项工作提供了对 Zn(II)电化学的深入理解，并为改善大脑中金属递质的检测提供了新工具。
