Nanosensing of Acetylcholine Molecules: Influence of the Association Mechanism
Journal
Langmuir
Journal Volume
38
Journal Issue
1
Pages
289-298
Date Issued
2022
Author(s)
Abstract
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. ? 2021 American Chemical Society.
Subjects
Molecules
Nanopores
Polyelectrolytes
Binding constant
Detection limits
Detection range
Ionic current
Nanosensing
Poly(ethyleneimine)
Polyelectrolyte layers
Space charge density
Surface-modified
Trace level
Association reactions
acetylcholine
polyelectrolyte
polyethyleneimine
ion transport
nanopore
Acetylcholine
Ion Transport
Polyethyleneimine
Type
journal article