TY - JOUR
T1 - Potentiometric pH Nanosensor for Intracellular Measurements
T2 - Real-Time and Continuous Assessment of Local Gradients
AU - Aref, Mohaddeseh
AU - Ranjbari, Elias
AU - García-Guzmán, Juan José
AU - Hu, Keke
AU - Lork, Alicia
AU - Crespo, Gaston A.
AU - Ewing, Andrew G.
AU - Cuartero, Maria
N1 - Funding Information:
This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement nos. 851957 and 787534). M.C. acknowledges support from the Royal Institute of Technology (KTH) and the Swedish Research Council (VR-2019-04142). M.A acknowledges the European Union’s Horizon 2020 research and innovation program (Marie Skłodowska-Curie grant agreement no. 793324). A.G.E acknowledges the Swedish Research Council (VR-2017-04366) and the Knut and Alice Wallenberg Foundation.
Publisher Copyright:
© 2021 The Authors. Published by American Chemical Society.
PY - 2021/11/30
Y1 - 2021/11/30
N2 - We present a pH nanosensor conceived for single intracellular measurements. The sensing architecture consisted of a two-electrode system evaluated in the potentiometric mode. We used solid-contact carbon nanopipette electrodes tailored to produce both the indicator (pH nanosensor) and reference electrodes. The indicator electrode was a membrane-based ion-selective electrode containing a receptor for hydrogen ions that provided a favorable selectivity for intracellular measurements. The analytical features of the pH nanosensor revealed a Nernstian response (slope of -59.5 mV/pH unit) with appropriate repeatability and reproducibility (variation coefficients of <2% for the calibration parameters), a fast response time (<5 s), adequate medium-term drift (0.7 mV h-1), and a linear range of response including physiological and abnormal cell pH levels (6.0-8.5). In addition, the position and configuration of the reference electrode were investigated in cell-based experiments to provide unbiased pH measurements, in which both the indicator and reference electrodes were located inside the same cell, each of them inside two neighboring cells, or the indicator electrode inside the cell and the reference electrode outside of (but nearby) the studied cell. Finally, the pH nanosensor was applied to two cases: (i) the tracing of the pH gradient from extra-to intracellular media over insertion into a single PC12 cell and (ii) the monitoring of variations in intracellular pH in response to exogenous administration of pharmaceuticals. It is anticipated that the developed pH nanosensor, which is a label-free analytical tool, has high potential to aid in the investigation of pathological states that manifest in cell pH misregulation, with no restriction in the type of targeted cells.
AB - We present a pH nanosensor conceived for single intracellular measurements. The sensing architecture consisted of a two-electrode system evaluated in the potentiometric mode. We used solid-contact carbon nanopipette electrodes tailored to produce both the indicator (pH nanosensor) and reference electrodes. The indicator electrode was a membrane-based ion-selective electrode containing a receptor for hydrogen ions that provided a favorable selectivity for intracellular measurements. The analytical features of the pH nanosensor revealed a Nernstian response (slope of -59.5 mV/pH unit) with appropriate repeatability and reproducibility (variation coefficients of <2% for the calibration parameters), a fast response time (<5 s), adequate medium-term drift (0.7 mV h-1), and a linear range of response including physiological and abnormal cell pH levels (6.0-8.5). In addition, the position and configuration of the reference electrode were investigated in cell-based experiments to provide unbiased pH measurements, in which both the indicator and reference electrodes were located inside the same cell, each of them inside two neighboring cells, or the indicator electrode inside the cell and the reference electrode outside of (but nearby) the studied cell. Finally, the pH nanosensor was applied to two cases: (i) the tracing of the pH gradient from extra-to intracellular media over insertion into a single PC12 cell and (ii) the monitoring of variations in intracellular pH in response to exogenous administration of pharmaceuticals. It is anticipated that the developed pH nanosensor, which is a label-free analytical tool, has high potential to aid in the investigation of pathological states that manifest in cell pH misregulation, with no restriction in the type of targeted cells.
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U2 - 10.1021/acs.analchem.1c03874
DO - 10.1021/acs.analchem.1c03874
M3 - Article
C2 - 34783529
AN - SCOPUS:85119922205
VL - 93
SP - 15744
EP - 15751
JO - Analytical Chemistry
JF - Analytical Chemistry
SN - 0003-2700
IS - 47
ER -