BACKGROUND

A biosensor is a device which measures the presence or amount of an analyte in a biological sample. A biosensor may include three main parts: i) biologically reactive elements sometimes referred to as reagents. Reagents may include biological materials (e.g., tissues, microorganisms, organelles, cell receptors, enzyme, antibodies, and take acid, etc.), a biologically derived material or biomimic, wherein the reagent may be created by biological engineering; ii) a transducer or detector element which may work in a physiochemical way (e.g., optical, piezoelectric, electrochemical, etc.) to transform the signal resulting from the interaction of the analyte being measured with the reagent into another signal that can be more easily measured and quantified; and iii) associated electronics or signal processors that are primarily responsible for the display of the results.

Enzymatic biosensors involve placement of an enzyme in close proximity to an electrode surface. The enzyme involved must catalyze a reaction between the analyte and reagent, which involves consuming of electroactive reactant or generation of electroactive species. The depletion or production process is then monitored. The monitored value of the depletion or production process may provide a direct measurement of the analyte concentration.

Certain small molecule analytes of interest may not be involved in enzymatic reactions. Rather, certain small molecule analytes may instead selectively bind to specific antibodies, aptamers, or affimers that may be linked to enzymes, such as those used in conventional enzyme-linked immunosorbent assays (ELISAs). An ELISA is a plate-based assay technique designed for detecting and quantifying substances such as peptides, proteins, antibodies and hormones. Specifically, in an ELISA, the substance of interest (i.e., target analyte, antigen, or biomolecule of interest) may be immobilized on a solid surface and then complexed with an antibody that is linked to an enzyme. In such assays, the antigen may be generally detected by assessing the conjugated enzyme activity via incubation with a substrate to produce a measurable product. In particular, the antigen may be typically immobilized through binding to a capture (primary) antibody that is chemically bound to a solid surface electrode.

While effective for antigen detection, conventional ELISA techniques must be performed through a series soak and wash steps where each component is introduced separately. Since such steps involve complicated bench-top methods that may take hours or days to complete, conventional ELISA detection is generally incompatible with real-time sampling and analysis.

SUMMARY OF THE INVENTION

Embodiment transdermal sampling and analysis devices may include a substrate, at least one disruptor mounted on the substrate in which the at least one disruptor is configured to generate a localized heat capable of altering permeability characteristics of a stratum corneum layer of skin of an organism, a reservoir configured to collect and contain a biological sample, at least two electrodes, and an electrochemical bioassay configured to determine levels of a target analyte in the biological sample. In some embodiment transdermal sampling and analysis devices, the at least one disruptor of the transdermal sampling and analysis device may be configured to generate a localized heat capable of altering permeability characteristics of a stratum corneum layer of skin of an organism.

In some embodiment transdermal sampling and analysis devices, the target analyte may be selected from cardiac troponin I (cTnI), melatonin, procalcitonin (PCT), heparin-binding protein (HBP), or interleukin-6 (IL-6).

In some embodiment transdermal sampling and analysis devices, the electrochemical bioassay may include a first small molecule binding element bound to a surface of at least one of the electrodes, at least one barrier layer covering a remainder of the surface, and a second small molecule binding element linked to an enzyme. In some embodiment transdermal sampling and analysis devices, the second small molecule binding element, the linked enzyme, and at least one substrate of the linked enzyme may be suspended in a hydrogel on top of the at least one of the electrodes.

In some embodiment transdermal sampling and analysis devices, the target analyte may be a small molecule that includes at least one binding site for each of the first small molecule binding element and the second small molecule binding element. In some embodiment transdermal sampling and analysis devices, the linked enzyme may catalyze a reaction of the at least one substrate. In some embodiment transdermal sampling and analysis devices, the reaction may cause transfer of electrons to the at least one of the electrodes when carried out in proximity to the first small molecule binding element.

In some embodiment transdermal sampling and analysis devices, the first and second small molecule binding elements may be selected from antibodies, aptamers, or affimers. In some embodiment transdermal sampling and analysis devices, the linked enzyme may be selected from alkaline phosphatase (ALP) or horseradish peroxidase (HRP), and the substrate of the linked enzyme may be selected from phenyl phosphate and hydrogen peroxide.

In some embodiment transdermal sampling and analysis devices, the electrochemical bioassay may further include an electron mediator suspended in the hydrogel. In some embodiment transdermal sampling and analysis devices, the electron mediator may be selected from ferrocene, osmium bipyridine complexes, ruthenium phthalocyanine complexes, a quinone, a tetrathialfulvalene (TTF), a tetracyanoquinodimethane (TCNQ), or a thionine.

