Diffusion control layer for use in electrochemical sensors
An electrochemical sensor may include a common reference electrode, at least one counter electrode, and a work electrode platform including a work electrode and at least one diffusion control layer. The work electrode may be electrically coupled to the common reference electrode. The electrode may include a reagent substrate configured to react with an analyte to produce a signal indicative of a concentration of the analyte. The at least one diffusion control layer may be configured to control the diffusion of the analyte to the work electrode.
1 . An electrochemical sensor comprising:
a common reference electrode;
at least one counter electrode; and
a work electrode platform comprising a first work electrode disposed on a first portion of a surface, a second work electrode laterally neighboring and in contact with the first work electrode and disposed on a second portion of the surface contiguous to the first portion of the surface, and at least one diffusion control layer coextensive to a pair of opposed ends of the first work electrode and the second work electrode, the at least one diffusion control layer comprising a matrix material defining a plurality of pores,
wherein the second work electrode is electrically coupled to the common reference electrode,
wherein the first work electrode comprises a first reagent substrate configured to react with a first analyte to produce a first signal indicative of a concentration of the first analyte,
wherein the second work electrode comprises a second reagent substrate configured to react with a second analyte to produce a second signal indicative of a concentration of the second analyte,
wherein the at least one diffusion control layer is configured to control diffusion of the first analyte through the plurality of pores of the at least one diffusion control layer to the first work electrode and diffusion of the second analyte through the plurality of pores of the at least one diffusion control layer to the second work electrode, and
wherein the at least one diffusion control layer comprises at least two dissolvable diffusion control layers being laterally adjacent to each other, the at least two dissolvable diffusion control layers comprising a first dissolvable diffusion control layer covering a surface of the first reagent substrate and a second dissolvable diffusion control layer covering a surface of the second reagent substrate.
2 . The electrochemical sensor of claim 1 , wherein the first dissolvable diffusion control layer comprises a first enzyme-driven membrane having a first additive configured to control the diffusion of the first analyte, and wherein the second dissolvable diffusion control layer comprises a second enzyme-driven membrane having a second additive different from the first additive configured to control the diffusion of the second analyte.
3 . The electrochemical sensor of claim 2 , wherein the first additive or the second additive includes at least one of dexamethasone or nitric oxide.
4 . The electrochemical sensor of claim 1 , wherein the first dissolvable diffusion control layer comprises a first permeable membrane defining first pores having a first average diameter, and wherein the second dissolvable diffusion control layer comprises a second permeable membrane defining second pores having a second average diameter larger than the first average diameter.
5 . The electrochemical sensor of claim 4 , wherein the first average diameter of the first pores is 5 angstroms to 200 angstroms, wherein the second average diameter of the second pores is 5 angstroms to 200 angstroms.
6 . The electrochemical sensor of claim 1 , wherein the first reagent substrate is configured to react with the first analyte at a first potential applied to the first reagent substrate to produce the first signal indicative of the concentration of the first analyte, and wherein the second reagent substrate is configured to react with the second analyte at a second potential applied to the second reagent substrate to produce the second signal indicative of the concentration of the second analyte.
7 . The electrochemical sensor of claim 1 , wherein the first reagent substrate is configured to exhibit a first impedance in response to a first potential in presence of the first analyte to produce a first current frequency, and wherein the second reagent substrate is configured to exhibit a second impedance in response to a second potential in presence of the second analyte to produce a second current frequency.
8 . The electrochemical sensor of claim 1 , wherein the at least one diffusion control layer includes one or more metal-organic frameworks, wherein the one or more metal-organic frameworks are disposed over one or both of the first reagent substrate and the second reagent substrate, and wherein at least one of the one or more metal-organic frameworks includes a lattice structure configured to separate the first analyte or the second analyte from a fluid in response to application of an energy, a current, or a material to the at least one of the one or more metal-organic frameworks.
9 . The electrochemical sensor of claim 8 , wherein the lattice structure defines a plurality of apertures having a size or a shape of the first analyte or the second analyte.
10 . The electrochemical sensor of claim 1 , wherein the at least one diffusion control layer includes a self-assembled monolayer, and wherein the self-assembled monolayer is disposed over the first reagent substrate or the second reagent substrate and configured to separate the first analyte or the second analyte from a fluid.
11 . The electrochemical sensor of claim 10 , wherein the self-assembled monolayer comprises 16-mercaptohexadecanoic acid (MHDA) and carbodiimide (EDC)/N-hydroxysuccinimide (NHS) complex.
12 . The electrochemical sensor of claim 1 , wherein the at least one diffusion control layer includes one or more pharmaceuticals, wherein the one or more pharmaceuticals are disposed over the first reagent substrate or the second reagent substrate, and wherein the one or more pharmaceuticals are configured to inhibit binding of the first analyte or the second analyte to the first reagent substrate or the second reagent substrate.
13 . The electrochemical sensor of claim 12 , wherein the one or more pharmaceuticals comprise dexamethasone.
14 . The electrochemical sensor of claim 1 , wherein the at least one counter electrode has a surface area larger than a surface area of each of the first and second work electrodes.
15 . A method of forming an electrochemical sensor, the method comprising:
forming a common reference electrode;
forming at least one counter electrode; and
forming a work electrode platform comprising a first work electrode disposed on a first portion of a surface, a second work electrode laterally neighboring and in contact with the first work electrode and disposed on a second portion of the surface contiguous to the first portion of the surface, and at least one diffusion control layer coextensive to a pair of opposing ends of the first work electrode and the second work electrode, the at least one diffusion control layer comprising a matrix material defining a plurality of pores,
wherein the second work electrode is electrically coupled to the common reference electrode,
wherein the first work electrode comprises a first reagent substrate configured to react with a first analyte to produce a signal indicative of a concentration of the first analyte,
wherein the second work electrode comprises a second reagent substrate configured to react with a second analyte to produce a signal indicative of a concentration of the second analyte,
wherein the at least one diffusion control layer is configured to control diffusion of the first analyte through the plurality of pores of the at least one diffusion control layer to the first work electrode and diffusion of the second analyte through the plurality of pores of the at least one diffusion control layer to the second work electrode, and
wherein the at least one diffusion control layer comprises at least two dissolvable diffusion control layers being laterally adjacent to each other, the at least two dissolvable diffusion control layers comprising a first dissolvable diffusion control layer covering a surface of the first reagent substrate and a second dissolvable diffusion control layer covering a surface of the second reagent substrate.