NAD(P)-dependent responsive enzymes, electrodes and sensors, and methods for making and using the same
Inventors
Ouyang, Tianmei • Feldman, Benjamin J.
Assignees
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Publication Number
US-12686881-B2
Publication Date
2026-07-21
Expiration Date
Abstract
NADP-dependent oxidoreductase compositions, and electrodes, sensors and systems that include the same. Analyte sensors include an electrode having a sensing layer disposed thereon, the sensing layer comprising a polymer and an enzyme composition distributed therein. The enzyme composition includes nicotinamide adenine dinucleotide phosphate (NAD(P)+) or derivative thereof, an NAD(P)+-dependent dehydrogenase; an NAD(P)H oxidoreductase; and an electron transfer agent comprising a transition metal complex.
Core Innovation
The disclosed subject matter relates to NAD(P)+-dependent oxidoreductase enzyme compositions and electrochemical analyte sensors. It describes a sensor that detects D-3-hydroxybutyrate in vivo using a transcutaneously positioned portion in contact with interstitial fluid, and a working electrode that generates a signal associated with the level of D-3-hydroxybutyrate.
A key element is an enzyme composition disposed on the working electrode that includes NAD(P)+, or a derivative thereof, D-3-hydroxybutyrate dehydrogenase, diaphorase, and an electron transfer agent together with a polymer sensing layer. The NAD(P)+ or derivative thereof is not covalently bonded to the polymer, and the composition is used to produce an electrochemical signal associated with D-3-hydroxybutyrate concentration.
The sensor further includes a mass transport limiting membrane disposed over the enzyme composition. The membrane limits flux of D-3-hydroxybutyrate to the working electrode to support a linear relationship between signal and D-3-hydroxybutyrate concentration over a specified range. The description includes example sensor behavior such as linearity metrics and signal decay over time.
Claims Coverage
The relevant independent claim is directed to an in vivo transcutaneous electrochemical sensor for detecting D-3-hydroxybutyrate, including a working electrode enzyme composition and a mass transport limiting membrane, with a defined linear signal response over a concentration range. The independent claim includes three main inventive feature groupings: sensor placement, enzyme composition architecture, and mass transport limiting membrane control of analyte flux.
In vivo transcutaneous D-3-hydroxybutyrate sensor placement
A sensor for detecting D-3-hydroxybutyrate in vivo having a first portion configured to be positioned above a user's skin and a second portion configured to be transcutaneously positioned in the user's skin and in contact with the user's interstitial fluid to monitor the level of D-3-hydroxybutyrate in vivo.
Working electrode enzyme composition with noncovalently bound NAD(P)+
A second portion including a working electrode having an enzyme composition disposed thereon, the enzyme composition comprising NAD(P)+, or derivative thereof, not covalently bonded to the polymer, D-3-hydroxybutyrate dehydrogenase, diaphorase, an electron transfer agent, and a polymer.
Mass transport limiting membrane that shapes flux and enables linear signal response
A mass transport limiting membrane disposed over the enzyme composition, wherein the working electrode is configured to generate a signal associated with the level of D-3-hydroxybutyrate, wherein the mass transport limiting membrane limits flux of D-3-hydroxybutyrate to the working electrode, and wherein the signal increases linearly as a function of D-3-hydroxybutyrate concentration over a range of 0 mM to 10 mM.
Quantitative linear correlation requirement
A signal that correlates with D-3-hydroxybutyrate concentration with an R2 of at least 0.99 across 0 mM to 10 mM.
Quantitative signal decay stability requirement
A signal that decays no more than 8% when exposed to a specified D-3-hydroxybutyrate concentration for 45 hours.
Specific mass transport limiting membrane material
The mass transport limiting membrane comprises polyurethane or polyether urethane.
Mass transport limiting membrane includes hydrophilic or hydrophobic modifier
The mass transport limiting membrane further comprises a hydrophilic or hydrophobic modifier.
Crosslinker-based immobilization of enzyme composition
The enzyme composition further comprises a crosslinker to immobilize the enzyme composition on a surface of the working electrode.
Overall claim coverage centers on an in vivo transcutaneous D-3-hydroxybutyrate sensor with a working electrode enzyme composition using NAD(P)+, or derivative thereof, that is not covalently bonded to a polymer, combined with diaphorase, D-3-hydroxybutyrate dehydrogenase, and an electron transfer agent. The sensor uses a mass transport limiting membrane to limit analyte flux and achieve linear signal response over 0 mM to 10 mM, with dependent refinements on R2, decay, membrane material, modifiers, and crosslinker-based immobilization.
Stated Advantages
Provides a signal associated with the level of D-3-hydroxybutyrate in vivo using a transcutaneous sensor in contact with interstitial fluid.
Produces a signal that increases linearly with D-3-hydroxybutyrate concentration over 0 mM to 10 mM.
Supports high quantitative linear correlation, with an R2 of at least 0.99 across 0 mM to 10 mM.
Provides signal stability, with signal decay no more than 8% under exposure for 45 hours.
Documented Applications
In vivo monitoring of the level of D-3-hydroxybutyrate using a transcutaneous sensor in contact with a user's interstitial fluid.
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