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Determination of Selectivity Coefficients of Sodium and Potassium Ion-Selective Electrode Using Porous Silicon N-Type (100) Based Extended Gate Field Effect Transistor
摘要： Determination of Selectivity Coefficients of Sodium and Potassium Ion-Selective Electrode Using Porous Silicon N-Type (100) Based Extended Gate Field Effect Transistor
关键词： Sodium,Selectivity Coefficients,Porous Silicon,Extended Gate Field Effect Transistor,Ion-Selective Electrode,Potassium
更新于2025-09-23 15:23:52
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Iona??Selective Sensors Based on Lasera??Induced Graphene for Evaluating Human Hydration Levels Using Urine Samples
摘要： Complex graphene electrode fabrication protocols including conventional chemical vapor deposition and graphene transfer techniques as well as more recent solution-phase printing and postprint annealing methods have hindered the wide-scale implementation of electrochemical devices including solid-state ion-selective electrodes (ISEs). Herein, a facile graphene ISE fabrication technique that utilizes laser induced graphene (LIG), formed by converting polyimide into graphene by a CO2 laser and functionalization with ammonium ion (NH4+) and potassium ion (K+) ion-selective membranes, is demonstrated. The electrochemical LIG ISEs exhibit a wide sensing range (0.1 × 10?3–150 × 10?3 m for NH4+ and 0.3 × 10?3–150 × 10?3 m for K+) with high stability (minimal drop in signal after 3 months of storage) across a wide pH range (3.5–9.0). The LIG ISEs are also able to monitor the concentrations of NH4+ and K+ in urine samples (29–51% and 17–61% increase for the younger and older patient; respectively, after dehydration induction), which correlate well with conventional hydration status measurements. Hence, these results demonstrate a facile method to perform in-field ion sensing and are the first steps in creating a protocol for quantifying hydration levels through urine testing in human subjects.
关键词： graphene,solid-contact ion-selective electrode (ISE),potentiometry,urinalysis,hydration
更新于2025-09-23 15:21:01
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Light addressable ion sensing for real-time monitoring of extracellular potassium
摘要： Visualization of ion distribution has broad applications. We report here on a light addressable potassium (K+) sensor where light illumination of a semiconducting silicon electrode substrate results in a localized activation of the faradaic electrochemistry at the illuminated spot. This allows one, by electrochemical control, to oxidize surface bound ferrocene moieties that in turn trigger K+ transfer from the overlaid K+-selective film to the solution phase. The resulting voltammetric response is shown to be K+-selective, where peak position is a direct function of K+ activity at the surface of electrode. This concept was used to measure extracellular K+ concentration changes by stimulating living breast cancer cells. The associated decrease of intracellular K+ level was confirmed with a fluorescent K+ indicator. In contrast to light addressable potentiometry, the approach introduced here relies on dynamic electrochemistry and may be performed in tandem with other electrochemical analysis when studying biological events on the electrode.
关键词： physiological condition,potassium,light activated electrochemistry,ion-selective electrode,potentiometry
更新于2025-09-23 15:21:01
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Light addressable ion sensing for real-time monitoring of extracellular potassium
摘要： Visualization of ion distribution has broad applications. We report here on a light addressable potassium (K+) sensor where light illumination of a semiconducting silicon electrode substrate results in a localized activation of the faradaic electrochemistry at the illuminated spot. This allows one, by electrochemical control, to oxidize surface bound ferrocene moieties that in turn trigger K+ transfer from the overlaid K+-selective film to the solution phase. The resulting voltammetric response is shown to be K+-selective, where peak position is a direct function of K+ activity at the surface of electrode. This concept was used to measure extracellular K+ concentration changes by stimulating living breast cancer cells. The associated decrease of intracellular K+ level was confirmed with a fluorescent K+ indicator. In contrast to light addressable potentiometry, the approach introduced here relies on dynamic electrochemistry and may be performed in tandem with other electrochemical analysis when studying biological events on the electrode.
关键词： physiological condition,potassium,light activated electrochemistry,ion-selective electrode,potentiometry
更新于2025-09-23 15:21:01
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Flower-like gold nanoparticles for enhanced photothermal anticancer therapy by the delivery of pooled siRNA to inhibit heat shock stress response
摘要： Reported reaction kinetics of metal nanoparticles in natural and engineered systems commonly have used proxy measurements to infer chemical transformations, but extension of these methods to complex media has proven difficult. Here, we compare the sulfidation rate of AgNPs using two ion selective electrode (ISE)-based methods, which rely on either (i) direct measurement of free sulfide, or (ii) monitor the free Ag+ available in solution over time in the presence of sulfide species. Most experiments were carried out in moderately hard reconstituted water at pH 7 containing fulvic acid or humic acid, which represented a broad set of known interferences in ISE. Distinct differences in the measured rates were observed between the two proxy-based methods and details of the divergent results are discussed. The two ISE based methods were then compared to direct monitoring of AgNP chemical conversion to Ag2S using synchrotron-based in situ X-ray diffraction (XRD). Using XRD, distinct rates from both ISE-based technique were observed, which demonstrated that ISE measurements alone are inadequate to discriminate both the rate and extent of AgNP sulfidation. XRD rate data elucidated previously unidentified reaction regimes that were associated with AgNP coating (PVP and citrate acid) and NOM components, which provided new mechanistic insight into metallic NP processing. In general, the extent of Ag2S formation was inversely proportional to surface coverage of the initial AgNP. Overall, methods to determine reaction kinetics of nanomaterials in increasingly complex media and heterogeneous size distributions to improve NP-based design and performance will require similar approaches.
关键词： ion selective electrode,X-ray diffraction,natural organic matter,silver nanoparticles,sulfidation kinetics
更新于2025-09-11 14:15:04