Tzuf Shay Peled, Michal Procházka, Jan Minar, Alex Schechter
{"title":"Unexpected Reduction of Silver(I) Cyanide Complex by Gold Yields a Surface-Limited Silver Monolayer","authors":"Tzuf Shay Peled, Michal Procházka, Jan Minar, Alex Schechter","doi":"10.1002/elsa.70026","DOIUrl":"https://doi.org/10.1002/elsa.70026","url":null,"abstract":"<p>Galvanic replacement reactions (GRR) between gold and silver are widely explored in various coating applications and, in particular, for producing a wide range of nanostructures. In all cases, gold metal complexes had a higher standard potential than silver, and therefore, Au(I) and Au(III) reacted with Ag. In all previously reported GRRs, metallic gold was deposited on top of the silver surface, while silver was oxidised and dissolved into the solution. In this paper, we show a unique case where cyanide ligands flip the reaction direction and lead to a surface-limited reaction. Thus, cyanide ligands from [Ag(CN)<sub>2</sub>]<sup>−</sup> complex stabilize the Au(I) complex dramatically and lower its standard reduction potential. The standard reduction potential of the cyanide gold complex ([Au(CN)<sub>2</sub>]<sup>−</sup>) is even lower than the standard reduction potential of the [Ag(CN)<sub>2</sub>]<sup>−</sup> complex (-0.6 and -0.31 V, respectively), so that the silver complex is able to oxidise metallic gold. In this GRR, ultrathin silver film (0.2–0.3 nm) was deposited on top of the gold surface, and the reaction stops after full coverage of the gold surface. Further investigation of this reaction showed it occurs both on Au nanoparticles and electrodeposited and sputtered gold films, with low dependency on the [Ag(CN)<sub>2</sub>]<sup>−</sup> concentration.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"6 3","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.70026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148237936","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kyoko Sugiyama, Fumiya Sato, Yuto Kunitastu, Kota Honda, Yusuke Hirabayashi, Yasufumi Takahashi, Katsuhiko Sato
{"title":"Facile and Rapid Fabrication of a Glutamate Sensor via Electropolymerization of o-Aminophenol","authors":"Kyoko Sugiyama, Fumiya Sato, Yuto Kunitastu, Kota Honda, Yusuke Hirabayashi, Yasufumi Takahashi, Katsuhiko Sato","doi":"10.1002/elsa.70022","DOIUrl":"https://doi.org/10.1002/elsa.70022","url":null,"abstract":"<p>Microfluidic analysis enables precise fluid manipulation and high-time-resolution measurements in microscale environments, and has attracted considerable attention as an analytical platform suitable for detecting spatiotemporally fluctuating biomolecules such as neurotransmitters. Glutamate is a major excitatory neurotransmitter in the central nervous system, and its real-time quantification is essential for understanding neural function and pathological mechanisms. In this study, aiming for application to microfluidic analysis, glutamate oxidase was immobilised within an electropolymerized poly(o-aminophenol) film, allowing facile and highly reproducible fabrication of enzyme-modified electrodes. When the response characteristics were evaluated using platinum electrodes of 3 mm and 25 µm in diameter, the microelectrode exhibited a high current density derived from radial diffusion and yielded a steady-state response. The limit of detection and limit of quantification obtained using the 3 mm electrode were 3.22 and 10.7 µM, respectively. Furthermore, the fabricated electrode showed no measurable response toward coexisting substances such as glutamine, aspartic acid, GABA, and glucose, indicating high substrate specificity, and the maximum response was obtained at pH 7.4. These results demonstrate that enzyme immobilisation via electropolymerization is a practical method suitable for integration with microelectrodes and microfluidic devices, and is expected to contribute to in situ glutamate monitoring as well as future applications in clinical diagnostic systems.</p>","PeriodicalId":93746,"journal":{"name":"Electrochemical science advances","volume":"6 2","pages":""},"PeriodicalIF":4.1,"publicationDate":"2026-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://chemistry-europe.onlinelibrary.wiley.com/doi/epdf/10.1002/elsa.70022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147686990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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