Electroenzymatic choline sensing at near the theoretical performance limit

Huang, Iwen; Clay, Mackenzie; Cao, Yunning; Nie, Jing; Guo, Yuwan; Monbouquette, Harold G.

doi:10.1039/d0an01939a

Cited by 5 publications

(7 citation statements)

References 41 publications

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“…Assuming K = 2 × 10 7 L/mol, the performance of the present nanopore-based device for Ach detection at pH 7 is much better than that of other methods. For example, the detection limit of the present device is 1–10 nM, which is orders of magnitude lower than that of other methods: 0.34 μM by electroenzymatic choline sensing, 0.3 μM through polymeric membrane electrodes, and 0.01 μM by PAMAM-Sal dendrimer …”

Section: Resultsmentioning

confidence: 68%

Nanosensing of Acetylcholine Molecules: Influence of the Association Mechanism

Chung

Hsu

2021

Langmuir

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A bullet-shaped nanopore surface modified by two polyelectrolyte (PE) layers, an inner polyethyleneimine (PEI) layer and an outer p-sulfonatocalix[4]-arene (SCX4) layer, is applied to sense trace levels of acetylcholine (Ach) molecules. We show that the higher the order of the association reaction of Ach with SCX4, the smaller the difference between the ionic current when Ach is present and that when it is absent, and so is the difference in the space charge density. In addition, the larger the binding constant K of that reaction, the lower the detection limit but narrower the detection range. Choosing pH 7 is most appropriate because if the pH is low, the concentration polarization of H+ is significant, and as it gets high, both PE layers become uncharged. At pH 7 and K = 2 × 107 L/mol, the detection limit of the nanopore ranges from 1 to 10 nM, which is orders of magnitude lower than that of the other approaches.

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Section: Resultsmentioning

confidence: 68%

Nanosensing of Acetylcholine Molecules: Influence of the Association Mechanism

Chung

Hsu

2021

Langmuir

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“…Unlike many applications of μCP for deposition of monolayer-thick patterns of protein, the goal here was to deposit a ∼4–5 μm-thick film corresponding to many equivalent enzyme layers on a well-defined microelectrode substrate in order to give optimal sensor performance. 24 The printing of a thick pattern with micron-scale, lateral spatial resolution is challenging; as it requires a good combination of surface wettability of the ink and ink viscosity (Fig. 6), since the chitosan film on the microelectrodes presents a hydrophilic surface for a water-based ink to wet and spread.…”

Section: Resultsmentioning

confidence: 99%

Microcontact printing of choline oxidase using a polycation-functionalized zwitterionic polymer as enzyme immobilization matrix

Zhao,

Cao,

Huang

et al. 2023

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“…Deviations from performance in vitro may even be more pronounced for sensors using different enzymes with slower kinetics, as differences in sensor response time are expected to have a large effect on the ability of simulated sensors to monitor quickly changing concentrations. 21 Within the context of the available sensing techniques, miniaturization of Glut sensors will be necessary (and is feasible considering recent sensitivity improvements) 15,40 if electroenzymatic sensing techniques are intended to operate with spatiotemporal resolution approaching that of devices for electrophysiological recordings, 41 which have resolved >250 Hz action potentials within ∼50 μm of a three-dimensional electrode array. 42 An approach to similar levels of spatiotemporal resolution with electroenzymatic sensors would provide exciting opportunities for simultaneous electrophysiological and electrochemical recordings and the correlation of chemical signaling with neuronal activity.…”

Section: Discussionmentioning

confidence: 99%

Simulated Performance of Electroenzymatic Glutamate Biosensors In Vivo Illuminates the Complex Connection to Calibration In Vitro

Clay

Monbouquette

2021

ACS Chem. Neurosci.

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Detailed simulations show that the relationship between electroenzymatic glutamate (Glut) sensor performance in vitro and that modeled in vivo is complicated by the influence of both resistances to mass transfer and clearance rates of Glut and H 2 O 2 in the brain extracellular space (ECS). Mathematical modeling provides a powerful means to illustrate how these devices are expected to respond to a variety of conditions in vivo in ways that cannot be accomplished readily using existing experimental techniques. Through the use of transient model simulations in one spatial dimension, it is shown that the sensor response in vivo may exhibit much greater dependence on H 2 O 2 mass transfer and clearance in the surrounding tissue than previously thought. This dependence may lead to sensor signals more than double the expected values (based on prior sensor calibration in vitro) for Glut release events within a few microns of the sensor surface. The sensor response in general is greatly affected by the distance between the device and location of Glut release, and apparent concentrations reported by simulated sensors consistently are well below the actual Glut levels for events occurring at distances greater than a few microns. Simulations of transient Glut concentrations, including a physiologically relevant bolus release, indicate that detection of Glut signaling likely is limited to events within 30 μm of the sensor surface based on representative sensor detection limits. It follows that important limitations also exist with respect to interpretation of decays in sensor signals, including relation of such data to actual Glut concentration declines in vivo. Thus, the use of sensor signal data to determine quantitatively the rates of Glut uptake from the brain ECS likely is problematic. The model is designed to represent a broad range of relevant physiological conditions, and although limited to one dimension, provides much needed guidance regarding the interpretation in general of electroenzymatic sensor data gathered in vivo.

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Electroenzymatic choline sensing at near the theoretical performance limit

Abstract: Using detailed simulations as a guide, an implantable, electroenzymatic choline sensor with sensitivity approaching the theoretical and unprecedented response time has been created.

Cited by 5 publications

References 41 publications

Nanosensing of Acetylcholine Molecules: Influence of the Association Mechanism

Nanosensing of Acetylcholine Molecules: Influence of the Association Mechanism

Microcontact printing of choline oxidase using a polycation-functionalized zwitterionic polymer as enzyme immobilization matrix

Simulated Performance of Electroenzymatic Glutamate Biosensors In Vivo Illuminates the Complex Connection to Calibration In Vitro

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