A dual electrochemical microsensor was fabricated for concurrent monitoring of hydrogen sulfide (H₂S) and calcium ions (Ca²⁺), which are closely linked important signaling species involved in various physiological processes. The dual sensor was prepared using a dual recessed electrode consisting of two platinum (Pt) microdisks (50 μm in diameter). Each electrode was individually optimized for the best sensing ability toward a target analyte. One electrode (WE1, amperometric H₂S sensor) was modified with electrodeposition of Au and electropolymerized polyaniline coating. The other electrode (WE2, all-solid-state Ca²⁺-selective electrode) was composed of Ag/AgCl onto the recessed Pt disk formed via electrodeposition/chloridation, followed by silanization and Ca²⁺-selective membrane loading. The current of WE1 and the potential of WE2 in a dual sensor responded linearly to H₂S concentration and logarithm of Ca²⁺ concentration, respectively, without a crosstalk between the sensing signals. Both WE1 and WE2 presented excellent sensitivity, selectivity (, i = CO, NO, O₂, NO₂^–, AP, AA, DA, and GABA; and , j = Na⁺, K⁺, and Mg²⁺), and fast response time with reasonable stability (during ca. 6 h in vivo experiment). Particularly, WE2 prepared using a mixture of two ionophores (ETH1001 and ETH129) and two plasticizers (2-nitrophenyl octyl ether and bis(2-ethylhexyl) sebacate) showed a very shortened response time (t_R to attain the ΔE/Δt slope of 0.6 mV/min = 3.0 ± 0.2 s, n ≥ 10), a critically required factor for real-time analysis. The developed sensor was utilized for simultaneous real-time monitoring of H₂S and Ca²⁺ changes at the brain cortex surface of a living rat during spontaneous epileptic seizures induced by a cortical 4-aminopyridine injection. The dynamic changes of H₂S and Ca²⁺ were clearly observed in an intimate correlation with the electrophysiological recording of seizures, demonstrating the sensor feasibility of in vivo and real-time simultaneous measurements of H₂S and Ca²⁺.

中文翻译：

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电化学双 H2S/Ca2+ 微传感器的研制及其在大鼠癫痫模型中的体内应用

制造了一种双电化学微传感器，用于同时监测硫化氢 (H ₂ S) 和钙离子 (Ca ²⁺ )，它们是参与各种生理过程的重要信号物质。双传感器使用由两个铂 (Pt) 微盘（直径 50 μm）组成的双凹槽电极制备。每个电极都经过单独优化，以获得对目标分析物的最佳传感能力。一个电极（WE1，电流式 H ₂ S 传感器）通过电沉积 Au 和电聚合聚苯胺涂层进行了修改。另一个电极（WE2，全固态 Ca ²⁺选择性电极）由 Ag/AgCl 组成，位于通过以下方式形成的凹陷 Pt 盘上电沉积/氯化，然后是硅烷化和 Ca ²⁺选择性膜加载。双传感器中WE1的电流和WE2的电位分别对H ₂ S浓度和Ca ²⁺浓度的对数呈线性响应，传感信号之间没有串扰。既WE1和WE2呈现优良的灵敏度，选择性（，我= CO，NO，O- ₂，NO ₂ ^-，AP，AA，DA，和GABA;和，Ĵ = NA ⁺，K ⁺和Mg ²⁺），和具有合理稳定性的快速响应时间（在体内约6 小时内实验）。特别是，使用两种离子载体（ETH1001 和 ETH129）和两种增塑剂（2-硝基苯基辛基醚和双（2-乙基己基）癸二酸酯）的混合物制备的 WE2 显示出非常短的响应时间（t _R以达到 Δ E /Δ t 0.6 mV/min 的斜率 = 3.0 ± 0.2 s，n ≥ 10)，这是实时分析的关键因素。开发的传感器用于在皮层 4-氨基吡啶注射诱导的自发性癫痫发作期间同时实时监测活大鼠大脑皮层表面的 H ₂ S 和 Ca ²⁺变化。H ₂ S 和 Ca ²⁺的动态变化清楚地观察到与癫痫的电生理记录密切相关，证明了传感器在体内和实时同时测量 H ₂ S 和 Ca ^{2+ 的}可行性。