Carbon-Based Solid-State Calcium Ion-Selective Microelectrode and Scanning Electrochemical Microscopy: A Quantitative Study of pH-Dependent Release of Calcium Ions from Bioactive Glass.
Carbon-Based Solid-State Calcium Ion-Selective Microelectrode and Scanning Electrochemical Microscopy: A Quantitative Study of pH-Dependent Release of Calcium Ions from Bioactive Glass.
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碳基固态钙离子选择性微电极和扫描电化学显微镜：生物活性玻璃中钙离子pH依赖性释放的定量研究。
DOI：
10.1021/acs.analchem.5b04614
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发表时间：
2016-03-15
影响因子：
7.4
通讯作者：
Koley D
中科院分区：
文献类型：
--
作者：
Ummadi JG;Downs CJ;Joshi VS;Ferracane JL;Koley D
固态离子选择性电极由于其固有的快速响应时间和易于小型化而被用作扫描电化学显微镜（SECM）探针。在这项研究中，我们报告了一种固态，低聚氯乙烯，碳基钙离子选择性微电极（Ca 2 +-ISME），直径为25 μm，能够执行电流接近曲线，并作为电位传感器的发展。Ca 2 +-ISME具有5 µM至200 mM的宽线性响应范围，其近能斯特斜率为28 mV/log [aCa 2 +]。Ca 2 +-ISME的计算检测限为1 µM。这种Ca 2 +-ISME的选择性系数为log KCa 2+，对于Mg 2+、Na+和K+，A分别为−5.88、−5.54和−6.31。我们使用这种新型的Ca 2 +-ISME作为SECM探针，定量绘制由模型基底生物活性玻璃（BAG）产生的化学微环境。在酸性条件下（pH 4.5），发现BAG将钙离子浓度从0.7 mM（人工唾液中的[Ca 2 +]）增加到表面上方20 µm处的1.4 mM。此外，固态双SECM pH探针被用来关联的钙离子的释放与局部pH值的变化。三维pH值和钙离子分布映射也通过使用这些固态探针获得。BAG上方的pH和Ca 2+的定量映射阐明了BAG在酸性条件下中和和释放钙离子的有效性。
Solid-state ion-selective electrodes are used as scanning electrochemical microscope (SECM) probes because of their inherent fast response time and ease of miniaturization. In this study, we report the development of a solid-state, low-poly(vinyl chloride), carbon-based calcium ion-selective microelectrode (Ca2+-ISME), 25 µm in diameter, capable of performing an amperometric approach curve and serving as a potentiometric sensor. The Ca2+-ISME has a broad linear response range of 5 µM to 200 mM with a near Nernstian slope of 28 mV/log [aCa2+]. The calculated detection limit for Ca2+-ISME is 1 µM. The selectivity coefficients of this Ca2+-ISME are log KCa2+,A = −5.88, −5.54, and −6.31 for Mg2+, Na+, and K+, respectively. We used this new type of Ca2+-ISME as an SECM probe to quantitatively map the chemical microenvironment produced by a model substrate, bioactive glass (BAG). In acidic conditions (pH 4.5), BAG was found to increase the calcium ion concentration from 0.7 mM ([Ca2+] in artificial saliva) to 1.4 mM at 20 µm above the surface. In addition, a solid-state dual SECM pH probe was used to correlate the release of calcium ions with the change in local pH. Three-dimensional pH and calcium ion distribution mapping were also obtained by using these solid-state probes. The quantitative mapping of pH and Ca2+ above the BAG elucidates the effectiveness of BAG in neutralizing and releasing calcium ions in acidic conditions.