Anti-interferent barrier layers for non-invasive transdermal sampling and analysis device
Inventors
Vidalis, Joseph J • Marcanio, Joseph A • Currie, John Frederick • Nadarajan, Sundar • Woodvine, Helena
Assignees
Cambridge Medical Technologies LLC
Publication Number
US-9968284-B2
Publication Date
2018-05-15
Expiration Date
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Abstract
A system and methods are provided for reducing electrochemical interference in a transdermal sampling and analysis device. A one-step transdermal glucose biosensor may calculate glucose concentrations that are artificially high compared to traditional home blood glucose sensors due to interference, which may be mitigated by forming an anti-interferent barrier layer over a sensing element. The anti-interferent barrier layer may be formed over a sensing layer and may possess a charge type which repels interferent molecules having the same charge type from interacting with the sensing layer disposed below the anti-interferent barrier layer.
Core Innovation
A system and methods are provided for reducing electrochemical interference in a transdermal sampling and analysis device. The invention provides an anti-interferent barrier layer formed over a sensing layer disposed on a sensing element, wherein the anti-interferent barrier layer possesses a charge type that repels interferent molecules having the same charge type from interacting with the sensing layer below the anti-interferent barrier layer. This barrier layer mitigates effects of non-analyte chemical species (interferents) that can cause inaccurate measurements in a biosensing process by falsely presenting the appearance of more or less of the analyte being detected.
Embodiments describe a transdermal sampling and analysis device that includes a substrate with at least one disruptor configured to generate localized heat capable of altering permeability characteristics of a stratum corneum, a reservoir to collect a biological sample, and a biological sensing element with at least two sensing electrodes. In such embodiments, a surface of at least one sensing electrode is coated with a sensing layer and the sensing layer is covered with an anti-interferent barrier layer having an opposite charge type, or alternatively the barrier layer molecules may be conjugated to molecules of the sensing layer, or the barrier layer may repel charged biological reducing species to prevent interaction between an electron mediator and the charged biological reducing species.
The disclosure further describes solid state mediated sensors in which an enzyme and an electron mediator are immobilized by a polymer to form a sensing layer anchored to a sensing electrode, and the application of a charged anti-interferent barrier layer atop that sensing layer to prevent interaction between charged biological reducing species and the electron mediator. Alternative embodiments include composite barrier layers formed from multiple layers with alternating charges to improve selectivity, and barrier layers associated with the sensing layer via charge interaction, conjugation, or other forces.
Claims Coverage
Two independent claims are identified: one directed to a transdermal sampling and analysis device and one directed to a method of preventing interference in a transdermal biosensor device. The following inventive features are extracted from those independent claims.
Disruptor configured to generate localized heat
At least one disruptor mounted on a substrate configured to generate a localized heat capable of altering permeability characteristics of a stratum corneum layer of skin of an organism.
Circular sensing chamber and sensing channels directing sample flow
A sensing chamber forming a circular shape around a periphery of the reservoir and circular sensing channels configured to guide the biological sample through the sensing chamber, wherein the biological sample is directed over an entire surface of each of the at least two sensing electrodes.
Sensing layer comprising enzyme, electron mediator, and polymer
A sensing layer formed by immobilizing an enzyme and an electron mediator by a polymer, wherein the polymer is anchored to a sensing electrode to create a solid state sensor.
Anti-interferent barrier layer with opposite charge covering sensing layer
The sensing layer is covered with an anti-interferent barrier layer having at least a second charge type, wherein the first charge type of the sensing layer is an opposite charge type from the second charge type of the anti-interferent barrier layer.
Application of anti-interferent barrier layer to prevent mediator interaction
Applying an anti-interferent barrier layer atop the sensing layer such that charge type repulsion between the anti-interferent barrier layer and charged biological reducing species prevents interaction between the charged biological reducing species and the electron mediator.
Composite barrier layer with alternating charges
A composite barrier layer comprising a first anti-interferent barrier layer having a second charge type and a second anti-interferent barrier layer having the first charge type, wherein the second anti-interferent barrier layer is disposed on top of the first anti-interferent barrier layer, and the composite may comprise a plurality of alternating layers.
The independent device and method claims center on integrating a disruptor-driven transdermal sampling architecture with a solid state sensing layer (enzyme, mediator, polymer) and an anti-interferent barrier strategy—either charged or conjugated, including multi-layer composites—to prevent charged biological reducing species from interacting with the electron mediator and thereby reduce interference in analyte measurements.
Stated Advantages
Improve the accuracy of a transdermal sampling and analysis device by mitigating the effects of non-analyte chemical species (interferents) upon analyte measurement.
Prevent interferents from causing an inaccurate reading of analyte concentration in a sample by repelling similarly charged interferent molecules from the sensing layer.
Enable in situ measurements to approximate in vitro measurements by reducing interference from redox species in interstitial fluid.
Composite barrier layers with alternating charges may improve the selectivity of the barrier.
A non-invasive, single-step transdermal sampling and analysis approach reduces the need for larger biological samples and may reduce potential contamination and patient discomfort compared to conventional finger stick methods.
Documented Applications
Non-invasive transdermal glucose biosensor for in situ measurement of glucose concentration from interstitial fluid (ISF).
A one-step home monitoring glucose biosensor that disrupts the stratum corneum, collects interstitial fluid, reacts the sample with a biologically reactive element, and senses generated signals within a singular device.
Solid state mediated sensors incorporated into transdermal sampling and analysis devices to determine levels of an analyte (e.g., glucose) using an immobilized enzyme and an electron mediator.
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