GB2584899A

GB2584899A - A wound monitoring apparatus and associated method

Info

Publication number: GB2584899A
Application number: GB1908904.4A
Authority: GB
Inventors: Baki Abdulrahman; Abdulhakeem Hamid Omar; Saleh Ehab; Al-Deen Abu Awwad Hosam
Original assignee: Curei Ltd
Current assignee: Curei Ltd
Priority date: 2019-06-21
Filing date: 2019-06-21
Publication date: 2020-12-23
Also published as: GB201908904D0

Abstract

Monitoring apparatus 201 for a wound 206 comprises a substrate having a wound region 203 and a detection region 204 connected by one or more fluid channels 205. The detection region 204 comprises a plurality of distinct sensing markers 207a-d (e.g. a dye) each configured to undergo a detectable optical change (e.g. colour, absorption, reflectance, transparency etc.) in response to a different wound parameter (including e.g. temperature, pH, moisture, or a pathogen). The sensing markers are tethered, for example by electrostatic or chemical vapour deposition, within the detection region of the substrate to inhibit removal. The markers may be tethered to a cover configured to overlay the substrate. The fluid channels may have different volumes, cross-sections or tapering to provide different transfer rates. Reference markers for comparison, as well as light sources and photodetectors may be present. The monitor may facilitate early-warning of wound deterioration and avoid costly medical inspections.

Description

A WOUND MONITORING APPARATUS AND ASSOCIATED METHOD

Technical Field

The present disclosure relates to wound healing in human or animal bodies and, in particular, concerns an apparatus and associated method for monitoring said wound healing.

Background

Wound healing is the multi-stage process by which skin and tissue layers undergo repair following injury, and comprises biochemical events that include coagulation, hemostasis, inflammation, tissue growth and tissue remodelling/maturation. To mitigate the formation of a non-healing chronic wound, and/or unintentional infection, it is important that wound healing proceeds without negative interruption.

To support healthy wound healing and speed up the time for patient recovery, one or more wound dressings can be applied to a wound as a form of wound care. Modern forms of wound dressing often function as more than a physical barrier to protect a wound from its external environment; for example, they may be configured to absorb wound fluids (including exudate) or administer medicaments to a wound. If one of its principal functions is to dry a wound, a wound dressing may be characterised as a dry wound dressing. Alternatively, a wound dressing may be characterised as a wet wound dressing if one of its principal functions is to maintain a moist environment for a wound.

Given the underlying complexity of wound healing, combined with the range of distinct wound types, such as abscesses, burns, open wounds and ulcers, it is apparent that wound dressings can be rationally selected for application to a wound to maximise their effectiveness. Determining the most suitable type of wound dressing to apply to a wound, and/or an appropriate time to replace said wound dressing, may be achieved (at least in part) through one or more inspections of the wound by the subject or by a medical professional. For the medical professional, however, these inspections can be costly both in terms of time and money spent. Also, in general these inspections may not necessarily be scheduled in a manner that facilitates the early-warning of wound deterioration, and may even by timed prematurely, thereby increasing the risk of delayed healing and infection.

The apparatus and method disclosed herein may address this issue.

The listing or discussion of a prior-published document or any background in this specification should not necessarily be taken as an acknowledgement that the document or background is part of the state of the art or is common general knowledge. One or more aspects/embodiments of the present disclosure may or may not address one or more of

the background issues.

Summary

According to a first aspect, there is provided a wound monitoring apparatus comprising a substrate having a wound region and a detection region connected to one another by one or more fluid channels configured to transfer fluid from the wound region to the detection region, the detection region comprising a plurality of distinct sensing markers each configured to interact with the fluid transferred via the one or more fluid channels and undergo a detectable optical change in response to a different wound parameter, wherein the plurality of sensing markers are tethered within the detection region of the substrate to inhibit removal of the sensing markers from the detection region by the fluid.

The plurality of sensing markers may be configured to undergo a detectable optical change in response to one or more of physical, chemical and biological wound parameters.

The plurality of sensing markers may be configured to undergo a detectable optical change in response to two or more of the following wound parameters: oxygen, temperature, pH, moisture, an irritant and a pathogen.

Each sensing marker may be configured to undergo a detectable optical change in response to one specific wound parameter.

Each sensing marker may be configured such that the optical change varies with the magnitude of the respective wound parameter.

Each sensing marker may comprise a chemical substance configured to undergo a reversible optical change upon interaction with the fluid.

The chemical substance may comprise one or more of a dye, a pigment and a metal-ligand complex.

The plurality of distinct sensing markers may be configured to undergo a change in one or more of the following optical properties in response to the respective wound parameters: colour, absorption, reflectance, transmittance, transparency and opacity.

The sensing marker configured to undergo a detectable optical change in response to pH may comprise one or more of methyl red, phenol red, bromocresol purple (BCP), naphtholphthalein, 1-hydroxypyrene-3,6,8-trisulfonic acid (HPTS), fluorescein, seminaphthofluorescein (SNAFL), and ruthenium metal-ligand complexes.

The sensing marker configured to undergo a detectable optical change in response to oxygen may comprise one or more of methylene blue, myoglobin, haemoglobin, monofunctional p-isothiocyanatophenyl derivative of platinum (11)-coproporphyrin-I (PtCPNCS), platinum(11)-octaethylporphine (PtOEP), platinum(11)-octaethylporphine-ketone (PtOEPK), and bis(2,2'-bipyridine)(5-isothiocyanatophenanthroline) ruthenium bis (hexafluorophosphate) (Ru-NCS).

The sensing marker configured to undergo a detectable optical change in response to temperature may comprise one or more of thermochromic liquid crystals, thermochromic dyes, cholesteryl nonanoate, cyanobiphenyls, spirolactones, fluorans, spiropyrans, and fulg id es.

The sensing marker configured to undergo a detectable optical change in response to moisture may comprise one or more of copper (II) chloride, sudan-111 and alizarin red S, solvent orange 86, and graphene oxide.

The detection region may comprise a plurality of reference markers for comparison with respective sensing markers to facilitate detection of the optical change.

Each reference marker may comprise the same material as the respective sensing marker, and may be coated to prevent interaction of this material with the fluid.

Each reference marker may be positioned to avoid interaction with the fluid.

Each sensing marker may be one or more of physically and chemically tethered within the detection region.

The plurality of sensing markers may be tethered to the substrate within the detection region.

The apparatus may comprise a cover configured to overlay the substrate, and the sensing markers may be tethered to the underside of the cover such that the sensing markers are within the detection region when the cover is overlaid on the substrate.

The reference markers may be formed on the cover.

The fluid may comprise one or more of wound exudate and an external transfer fluid.

The fluid may comprise one or more of water, blood, sweat, plasma and hydrogel.

The substrate may comprise a plurality of fluid channels configured to transfer fluid from the wound region to each sensing marker.

The plurality of fluid channels may be associated with each sensing marker are configured to have different transfer rates for the fluid.

The plurality of fluid channels associated with each sensing marker may have one or more of different volumes, cross-sectional areas, and degrees of tapering to provide the different transfer rates for the fluid.

The substrate may comprise an absorbent region configured to absorb and retain the fluid following its interaction with the sensing markers to facilitate unidirectional transfer of the fluid from the wound region to the detection region.

The apparatus may comprise one or more light sources configured to illuminate the plurality of sensing markers with light, and one or more photodetectors configured to detect light reflected from or transmitted through the plurality of sensing markers to enable detection of the optical change.

The apparatus may comprise one or more light sources configured to illuminate the plurality of reference markers with light, and one or more photodetectors configured to detect light reflected from or transmitted through the plurality of reference markers for comparison with the light reflected from or transmitted through the plurality of respective sensing markers to facilitate detection of the optical change.

Each light source may be configured to illuminate a different respective sensing/reference marker.

Each photodetector may be configured to detect light reflected from or transmitted through a different respective sensing/reference marker.

The apparatus may be configured such that each sensing marker shares a light source and photodetector with a respective reference marker.

One or more of the substrate and cover may be optically transparent to facilitate detection of the light by the one or more photodetectors.

The one or more light sources and photodetectors may be contained within a housing, and the housing may comprise an opening configured to releasably receive the substrate to enable detection of the optical change.

The substrate may be configured to be used once, and the housing may be configured to be reused with further substrates.

One or more of the substrate and housing may be configured for attachment to a human or animal body to facilitate in-situ detection of the optical change.

The housing may be configured to inhibit contact between the fluid and one or more of the light sources and photodetectors when the substrate is received via the opening in the housing.

The opening may be dimensioned to inhibit contact between the fluid and one or more of the light sources and photodetectors; the light sources/photodetectors may be positioned within the housing to inhibit contact between the fluid and one or more of the light sources and photodetectors; and/or the substrate may be separated from the light sources/photodetectors by a fluid-impervious layer of material to inhibit contact between the fluid and one or more of the light sources and photodetectors.

The housing may comprise circuitry configured to process a signal output by the one or more photodetectors to enable detection of the optical change.

The apparatus may be configured to send one or more of the signal output by the one or more photodetectors and the processed signal to an external device.

The apparatus may be configured to send a signal output by the one or more photodetectors to an external device to enable detection of the optical change.

One or more of the apparatus and external device may be configured to determine a magnitude of each wound parameter based on the signal output by the one or more photodetectors.

The substrate may be formed from one or more of a substantially flexible material, a substantially stretchable material and a substantially resilient material.

The substrate may be formed from a biocompatible material.

The substrate may be formed from one or more of a metal; a ceramic; a thermoplastic; a thermosetting polymer; aliphatic polymers such as polyethylene (PE) and polypropylene (PP); alpha hydroxy acids such as poly lactic acid (PLA), poly(lactic-co-glycolic acid) (PLGA) and polyglycolide (PGA); silicon-based polymers such as poly dimethyl siloxane (PDMS), poly caprolactone (PCL), and polyamide (PA); unsaturated polymers with cross-linkable moieties such as polymethylmethacylate (PMMA); fluoropolymers such as polytetrafluoroethylene (PTFE); and complex copolymers such as polyurethane (PU).

According to a further aspect, there is provided a method of making the apparatus described herein, the method comprising: forming the one or more fluid channels on or within the substrate between the wound region of the substrate and the detection region of the substrate to enable transfer of fluid from the wound region to the detection region; and tethering the plurality of distinct sensing markers within the detection region of the substrate such that removal of the sensing markers from the detection region by the fluid is inhibited, each sensing marker configured to interact with the fluid transferred via the one or more fluid channels and undergo a detectable optical change in response to a different wound parameter.

According to a further aspect, there is provided a method of using the apparatus described herein, the method comprising: attaching the substrate to a human or animal body such that the wound region of the substrate is in fluid contact with a wound of the human or animal body; transferring fluid from the wound region of the substrate to the detection region of the substrate via the one or more fluid channels to enable interaction of the fluid with the plurality of sensing markers tethered within the detection region of the substrate; and monitoring any optical change of the plurality of sensing markers in response to the different wound parameters.

According to a further aspect, there is provided a wound monitoring apparatus comprising a substrate having a wound region and a detection region connected to one another by one or more fluid channels configured to transfer fluid from the wound region to the detection region, the detection region comprising a plurality of distinct sensing markers each configured to interact with the fluid transferred via the one or more fluid channels and undergo a detectable optical change in response to a different wound parameter.

According to a further aspect, there is provided a method of making the apparatus described herein, the method comprising: forming the one or more fluid channels on or within the substrate between the wound region of the substrate and the detection region of the substrate to enable transfer of fluid from the wound region to the detection region; and forming the plurality of distinct sensing markers within the detection region of the substrate, each sensing marker configured to interact with the fluid transferred via the one or more fluid channels and undergo a detectable optical change in response to a different wound parameter.

According to a further aspect, there is provided a method of using the apparatus described herein, the method comprising: attaching the substrate to a human or animal body such that the wound region of the substrate is in fluid contact with a wound of the human or animal body; transferring fluid from the wound region of the substrate to the detection region of the substrate via the one of more fluid channels to enable interaction of the fluid with the plurality of sensing markers within the detection region of the substrate; and monitoring any optical change of the plurality of sensing markers in response to the different wound parameters.

According to a further aspect, there is provided a wound monitoring apparatus as substantially described herein with reference to, and as illustrated by, the accompanying drawings.

According to a further aspect, there is provided a kit of pads comprising two or more of: a substrate as described herein; a cover as described herein; a housing as described herein; and an external device as described herein.

The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated or understood by the skilled person.

Corresponding computer programs (which may or may not be recorded on a carrier) for implementing one or more of the methods disclosed herein are also within the present disclosure and encompassed by one or more of the described example embodiments.

The present disclosure includes one or more corresponding aspects, example embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation. Corresponding means for performing one or more of the discussed functions are also within the present disclosure.

The above summary is intended to be merely exemplary and non-limiting.

Brief Description of the Figures

A description is now given, by way of example only, with reference to the accompanying schematic drawings, in which:-Figure 1 shows schematically the different stages of wound healing; Figure 2 shows in plan view a substrate of a wound monitoring apparatus; Figure 3 shows in perspective view a wound monitoring apparatus comprising the substrate of Figure 2; Figure 4 shows in perspective view a wound monitoring apparatus comprising a cover; Figure 5 shows the wound monitoring apparatus of Figure 4a from another perspective; Figure 6 shows in perspective view a wound monitoring apparatus comprising a 20 housing; Figure 7 shows in exploded view the wound monitoring apparatus of Figure 6; Figure 8 shows in the form of a flow chart a method of making a wound monitoring apparatus; Figure 9 shows in the form of a flow chart a method of using a wound monitoring apparatus; and Figure 10 shows schematically a computer-readable medium comprising a computer program configured to control, perform or enable the method of Figure 8 and/or 9.

Description of Specific Aspects/Embodiments

As indicated in the background section, wound dressings may not necessarily be applied to a wound in a manner that is wholly effective -from the perspective of facilitating healthy healing -and that minimises costs to the patient and the medical professional.

Furthermore, the application of a generic wound dressing to a wound, potentially combined with ad-hoc inspection of the wound, may impede wound recovery and increase the risk of wound infection.

Figure 1 shows schematically the different stages of wound healing, wherein the dashed line indicates the stage (proliferative and migration) prior to which the recovery of chronic wounds stalls. Figure 1 also indicates that a condition of a wound may be characterised by a plurality of wound parameters (e.g. 02, temperature, moisture and pH), and that bacteria, as a further parameter, is an unwanted agent in wound recovery.

Wound monitoring, as an aspect of wound care, can support healthy wound healing. For example, wound monitoring allows a condition of a wound to be determined, which can support any subsequent decision making in respect of treating the wound (e.g., schedule a new appointment, apply an alternative type of wound dressing, replace an existing wound dressing, or administer treatment to the wound). Known wound monitoring approaches can, however, be limited in respect of the information they provide, with corresponding constraints on their effectiveness. For example, the information may be qualitative and prone to interpretation bias, or may only reflect a single physiological parameter that cannot provide a complete indication of a condition of a wound. Such wound monitoring approaches may also place an undue burden on healthcare resources.

The apparatus and method described herein may provide a solution to this problem.

Figure 2 shows a substrate 202 of a wound monitoring apparatus 201. The substrate 202 comprises a wound region 203 in fluid contact with a wound 206, and a detection region 204 connected to one another by a plurality of fluid channels 205 (although in other examples there may only be one fluid channel 205). The plurality of fluid channels 205 are configured to transfer fluid from the wound region 203 to the detection region 204.

The detection region 204 comprises a plurality of distinct sensing markers 207a-d, each configured to interact with the fluid transferred via the plurality of fluid channels 205 and undergo a detectable optical change in response to a different wound parameter. In this way, the wound healing process (c.f. Figure 1 and the associated discussion) may be monitored without removing the wound dressing and any action required in respect of treating or caring for the wound can be taken reactively. Furthermore, by monitoring an optical change rather than, e.g., an electrical change, the present apparatus obviates the need for intrusive components (e.g., electrodes) in the vicinity of the wound 206 that may disturb wound healing.

The wound monitoring apparatus 201 may be positioned proximal to the wound 206 or an inflammatory area surrounding the wound 206. In general, the position of the wound monitoring apparatus 201 in relation to the wound 206 should facilitate fluid transfer from the wound 206 to the wound region 202 without impeding healing of the wound 206.

The plurality of sensing markers may be configured to undergo a detectable optical change in response to one or more of physical, chemical and biological wound parameters. In the example of Figure 2, the different wound parameters comprise moisture, temperature, pH and oxygen, but they could comprise other wound parameters such as an irritant and a pathogen.

The configuration of the plurality of distinct sensing markers 207a-d facilitates a correspondence between a distinct sensing marker 207a-d and a wound parameter. That is, the configuration facilitates an optical change to be detected with specificity. In some examples, each sensing marker 207a-d may be configured to undergo a detectable optical change in response to one specific wound parameter.

The distinct sensing markers 207a-d may be configured such that any detected optical change varies with the magnitude of the wound parameter, which can provide quantitative data on the wound healing process if calibrated. To enable this functionality, each distinct sensing marker 207a-d may comprise a chemical substance (e.g. a dye, pigment and/or metal-ligand complex) configured to undergo a reversible optical change upon interaction with the fluid. Here, the term "reversible" may be taken to mean that the chemical substance can return to a previous optical state following interaction with the fluid. Depending on the particular chemical substance and associated wound parameter, this reversibility may be passive (i.e. occurs automatically on removal of the fluid) or actively (i.e. requires exposure to a chemical reagent).

Examples of chemical substances configured to undergo an optical change is response to pH include methyl red, phenol red, bromocresol purple (BCP), naphtholphthalein, 1-hydroxypyrene-3,6,8-trisulfonic acid (HPTS), fluorescein, seminaphthofluorescein (SNAFL), and ruthenium metal-ligand complexes. Examples of chemical substances configured to undergo an optical change is response to oxygen include methylene blue, myoglobin, haemoglobin, monofunctional p-isothiocyanatophenyl derivative of platinum (II)-coproporphyrin-1 (PtCP-NCS), platinum(II)-octaethylporphine (PtOEP), platinum(II)- octaethylporphine-ketone (PtOEPK), and bis(2 2'-bipyridine)(5-isothiocyanatophenanthroline) ruthenium bis (hexafluorophosphate) (Ru-NCS). Examples of chemical substances configured to undergo an optical change in response to temperature include thermochromic liquid crystals, thermochromic dyes, cholesteryl nonanoate, cyanobiphenyls, spirolactones, fluorans, spiropyrans, and fulgides. Examples of chemical substances configured to undergo an optical change in response to moisture include copper (II) chloride, sudan-111 and alizarin red S, solvent orange 86, and graphene oxide.

The fluid that is transferred from the wound region 203 to the detection region 204 for interaction with the sensing markers 207a-d may comprise one or more of wound exudate (e.g. comprising at least one of water, blood, sweat and plasma from a wet wound) and an external transfer fluid (e.g. hydrogel). The external transfer fluid may be provided by a wet wound dressing to a dry wound and mix with the wound exudate. The external transfer fluid may dissolve chemical, biological and/or biochemical substances from the wound 206 prior to its transfer to the detection region 204 by the plurality of fluid channels 205.

The substrate 202 itself may be formed from one or more of a substantially flexible, stretchable and resilient material. Furthermore, if the substrate 202 is intended to be placed in direct physical contact with a human or animal body, it may be formed from a biocompatible material. In some examples, the substrate 202 may be formed from one or more of a metal; a ceramic; a thermoplastic; a thermosetting polymer; aliphatic polymers such as polyethylene (PE) and polypropylene (PP); alpha hydroxy acids such as poly lactic acid (PLA), poly(lactic-co-glycolic acid) (PLGA) and polyglycolide (PGA); silicon-based polymers such as poly dimethyl siloxane (PDMS), poly caprolactone (PCL), and polyamide (PA); unsaturated polymers with cross-linkable moieties such as polymethylmethacylate (PMMA); fluoropolymers such as polytetrafluoroethylene (PTFE); and complex copolymers such as polyurethane (PU).

The plurality of distinct sensing markers 207a-d may be tethered within the detection region 204 of the substrate 202 sufficiently to inhibit removal of the sensing markers from the detection region 204 by the fluid. The term "tethered" may be taken to mean that the sensing markers are secured or fixed in position within the detection region 204 of the substrate 202. For example, the sensing markers 207a-d may be physically attached to the substrate 202 within the detection region 204. By tethering the plurality of distinct sensing markers 207a-d within the detection region 204 of the substrate 202, contamination of one or more of the fluid and the wound by the chemical substances of the sensing markers 207a-d may be prevented or otherwise limited. The longevity of the sensing markers 207a-d could also be enhanced, which may be useful if the substrate 202 is to be used/reused over an extended period of time.

In some examples, tethering the plurality of distinct sensing markers 207a-d within the detection region 204 of the substrate 202 may including one or more of physical tethering and chemical tethering. Here, examples of physical tethering include electrostatic deposition of the sensing markers to a surface of the detection region by electrostatic deposition (e.g., adsorption and layer-by-layer deposition), atomic layer deposition, chemical vapour deposition, electro-chemical deposition and surface plasma polymerisation. Examples of chemical tethering include modifying an amino functionalised surface of the detection region with streptavidin biotin linkages, surface-initiated polymerisation and grafting (e.g., via atom transfer radical polymerisation (ATRP)), and using and amino functionalised surface (e.g., via the 1-Ethy1-3-(3-dimethylaminopropy1)-carbodiimide/N-hydroxysuccinimide (EDC/NHS) method).

The plurality of distinct sensing markers 207a-d may be configured to undergo a change in one or more of the following optical properties in response to the respective wound parameters: colour, absorption, reflectance, transmittance, transparency and opacity.

These optical properties may be associated with the UV, visible and/or near-IR bands of the electromagnetic spectrum.

The substrate 202 of Figure 2 further comprises a plurality of reference markers 208a-d for comparison with respective sensing markers 207a-d to facilitate detection of the optical change. The plurality of reference markers 208a-d may be used for a baseline or calibration measurement against which any detected optical change in the sensing markers 207a-d can be compared. For this purpose, each reference marker 208a-d may comprise the same material (chemical substance) as the respective sensing marker 207a-d -thereby facilitating a "like-for-like" comparison -and may be coated to prevent interaction of this material with the fluid. Additionally or alternatively, the reference markers 208a-d may be positioned to avoid interaction with the fluid. By preventing and/or avoiding interaction of the reference markers 208a-d with the fluid, the reliability of the reference markers 208a-d is improved and their ability to contaminate the fluid is mitigated.

One or more of the materials and dimensions of the fluid channels 205 may be configured to transfer the fluid using intermolecular forces, e.g. in the form of capillary, hydrophilic, oleophilic and/or lyophilic interactions. For example, the plurality of fluid channels 205 may be microfluidic channels. That is, the fluid may rely upon capillary forces to undergo transfer from the wound region 203 to the detection region 204. As such, a plurality of fluid channels 205 may be advantageous over a single, relatively wide channel that is not conducive for transferring fluid via capillary action.

The substrate 202 shown in Figure 2 comprises a plurality of fluid channels 205 configured to transfer fluid from the wound region 203 to each sensing marker 207a-d. In other words, each distinct sensing marker 207a-d has a corresponding set of fluid channels 205. The associated benefits of this arrangement include: mitigation against fluid channel blockage or damage when compared with an analogous approach that relies upon a single fluid channel 205 for fluid transfer; and providing a sufficient volume of fluid to the detection region 204 to facilitate detection of the optical change.

In the examples disclosed herein, the plurality of fluid channels 205 are not coated with the chemical substances of the sensing 207a-d and reference 208a-d markers. By not coating the plurality of fluid channels 205 with chemical substances, contamination of the fluid and/or wound by the chemical substances, alongside any adverse effect on the detected optical change, can be avoided.

In some examples, the plurality of fluid channels 205 associated with each sensing marker 207a-d are configured to have different transfer rates for the fluid. For instance, the plurality of fluid channels 205 associated with each sensing marker 207a-d may be configured to have one or more of different volumes, cross-sectional areas, and degrees of tapering to provide the different transfer rates for the fluid. By having different transfer rates, the time periods over which fluid from the wound 206 is received by the detection region 204 may be varied. This allows the wound 206 to be monitored over substantially distinct time periods (e.g., minutes, hours, days and weeks).

Figure 3 shows in perspective view a wound monitoring apparatus 301 comprising a substrate 302. The substrate 302 has a wound region 303 -shown here in fluid contact with a wound 306 -and a detection region 304 connected to one another by a plurality of fluid channels 305 configured to transfer fluid from the wound region 303 to the detection region 304. The substrate 302 further comprises a plurality of reference markers 308a-d for comparison with the respective sensing markers 307a-d to facilitate detection of the optical change. The configuration and functionality of the substrate 302 has been described previously with reference to Figure 2.

The wound monitoring apparatus 301 further comprises a plurality of light sources 309 configured to illuminate the plurality of sensing markers 307a-d with light, and a plurality of photodetectors 310 configured to detect light reflected from or transmitted through the plurality of sensing markers to enable detection of the optical change. The photodetectors 310 provide a more objective determination of the optical change than a manual visual inspection of the sensing markers 307a-d.

The plurality of light sources 309 are further configured to illuminate the plurality of reference markers 308a-d with light, with a further plurality of photodetectors 311 configured to detect light reflected from or transmitted through the plurality of reference markers 308a-d. This configuration enables a comparison with the sensing markers to be made, thereby facilitating detection of the optical change.

In the example shown in Figure 3, the plurality of light sources 309 are LEDs and the pluralities of photodetectors 310, 311 are phototransistors. In other examples, however, different types of light source 309 may be used instead of or in combination with the LEDs.

Similarly, other types of photodetector 310, 311 (such as photodiodes) may be used instead of or in combination with the phototransistors.

Also, the wound monitoring apparatus of Figure 3 is configured such that each sensing marker 307a-d shares a light source 209 with a respective reference marker 308a-d. In other examples, however, the wound monitoring apparatus 301 may be configured such that each sensing marker 307a-d shares a photodetector 310, 311 with a corresponding reference marker 308a-d. Alternatively, each light source 309 may be configured to illuminate a different sensing/reference marker, and each photodetector 310, 311 may be configured to detect light reflected from or transmitted through a different sensing/reference marker. When the photodetectors 310, 311 are configured to detect light transmitted through the sensing/reference markers, the substrate 302 may be optically transparent to facilitate said detection.

Figures 4 and 5 show in perspective view a wound monitoring apparatus 401, 501 comprising a cover 412, 512 configured to overlay a substrate 402, 502. The substrate 402, 502 comprises a wound region 403, 503 and a detection region 404, 504 connected to one another by a plurality of fluid channels 405, 505 as described previously with reference to Figure 2. The cover comprises a plurality of distinct sensing markers 407a-d, 507a-d formed on (e.g. tethered to) the underside 520 of the cover 412, 512 such that the sensing markers 407a-d, 507a-d are within the detection region 404, 504 when the cover 412, 512 is overlaid on the substrate 402, 502. The cover 412, 512 further comprises a plurality of reference markers 408a-d, 508a-d. These may be formed (for example) on the top side 421 or underside 520 of the cover 412, 512, although their positioning is less stringent than the sensing markers 407a-d, 507a-d which must be able to interact with the fluid.

The substrate 402, 502 further comprises an absorbent region 413, 513 configured to absorb and retain fluid following its interaction with the sensing markers 407a-d, 507a-d.

The absorbent region 413, 513 thus facilitates unidirectional transfer of fluid from the wound region 403, 503 to the detection region 404, 504 (i.e., inhibits backflow of the fluid to the wound region 403, 503), which helps to enable wound monitoring over extended periods of time and reduces the risk of wound contamination. The absorbent region 413, 513 may also increase the operational longevity of the wound monitoring apparatus 401, 501 by virtue of an increased capacity for storing fluid. In this respect, the absorbent region 413, 513 may be sized according to whether the wound monitoring apparatus 401, 501 is used for monitoring dry wounds or wet wounds.

The wound monitoring apparatus 401, 501 of Figures 4 and 5 further comprises a light source 409, 509 and a plurality of photodetectors 410-411, 510-511 as described previously with reference to Figure 3. In this example, the cover 412, 512 may be optically transparent to facilitate detection of the light from the light source 409, 509 by the photodetectors 410-411, 510-511.

Here, the wound monitoring apparatus 401, 501 of Figures 4 and 5 also comprises a processor 415, 515. The processor 415, 515 may be a microprocessor, including an Application Specific Integrated Circuit (ASIC). The processor 415, 515 is configured for general operation of the wound monitoring apparatus 401, 501 by providing signalling to, and receiving signalling from, the other components to manage their operation. The wound monitoring apparatus 401, 501 may be one or more of an electronic device, a portable electronic device, a wearable electronic device and a module for one or more of the same.

The substrate 402, 502 and cover 412, 512 may be considered a form a first module 414, 514 of the wound monitoring apparatus 401, 501 whilst the light source 409, 509, photodetectors 410-411, 510-511 and processor 415, 515 may be considered to form a second module 422, 522 of the wound monitoring apparatus 401, 501. In some examples, the first module 414, 514 may be configured for single use (i.e. disposable) and the second module 422, 522 may be configured for multiple use (i.e. non-disposable).

Figure 6 shows in perspective view a wound monitoring apparatus 601 comprising a housing 616 containing the light sources and photodetectors, the housing further comprising an opening 617 configured to releasably receive the substrate 602. This configuration helps to enable detection of the optical change by facilitating optical alignment between the sensing/reference markers and the one or more light sources and photodetectors.

This figure also shows the wound region 603 of the substrate 602 in fluid contact with a wound 606, and a plurality of fluid channels 605 as described previously with reference to Figure 2. In some examples, one or more of the substrate 602 and the housing 616 may be configured for attachment to a human or animal body to facilitate in-situ (of wound healing) detection of any optical change of the sensing markers to the fluid. That is, a time associated with a condition of a wound may be taken to correspond substantially to the time at which an optical change in the sensing markers was detected. In this respect, the substrate 602 and/or housing 616 may be attached to a human or animal body so that they are proximate to a wound 606 or an area surrounding a wound 606. For example, the wound region 603 of the substrate 602 may be provided between a wound 606 and any wound dressing applied to the wound 606 with the detection region and housing 616 being relatively distant from the wound dressing.

The housing 616 may be configured to inhibit contact between the fluid and one or more of the light sources and photodetectors when the substrate 602 is received via the opening 617 in the housing 616. This prevents exposure of the one or more light sources and photodetectors to the fluid, which could otherwise have a detrimental impact on the detection of any optical change (for example, by causing the light output characteristics of the one or more light sources to become uncertain and/or cause contamination of the fluid by any substances on the light sources and photodetectors).

In examples where the housing 616 is configured to inhibit contact between the fluid and one or more of the light sources and photodetectors, this may be achieved by suitable dimensioning of the opening 617. Additionally or alternatively, the light sources and photodetectors may be positioned within the housing 616 to inhibit contact with the fluid and/or the substrate 602 may be separated from the light sources/photodetectors by a fluid-impervious layer of material.

In some examples, the housing 616 may further comprise circuitry (e.g. comprising the processor 415, 515 described previously with reference to Figures 4 and 5) configured to process a signal output by the one or more photodetectors to enable detection of the optical change. In these examples, the wound monitoring apparatus 601 may also be configured to send (e.g. via a wired or wireless communication means) the processed signal to an external device (not shown). In other examples, the wound monitoring apparatus 601 may be configured to send the signal output by the one or more photodetectors to an external device (not shown) to enable detection of the optical change.

The output/processed signal may contain data that is used by a medical professional for substantially real-time and/or historic data analysis and wound monitoring. In turn, this may help to inform the medical professional of, e.g., the need to treat a wound or apply a new wound dressing. In this respect, the external device may be configured to create a message (e.g., an update or alert) for the medical professional that is based on the output/processed signal.

One or more of the apparatus 601 and external device may also be configured to determine a magnitude of each wound parameter based on the signal output by the one or more photodetectors, which can further inform the patient and/or medical professional of any subsequent action to take.

The substrate (with or without cover) may be considered to form a first module of the wound monitoring apparatus, whilst the housing 616, circuitry, light sources and photodetectors may be considered to form a second module of the wound monitoring apparatus. In this scenario, the first module may be configured for single use (i.e. disposable) and the second module may be configured to be reused with further substrates (i.e. non-disposable).

Figure 7 shows the wound monitoring apparatus 701 of Figure 6 in exploded view. As can be seen, the housing comprises top and bottom housing portions 723 which are configured to be coupled together to house the circuitry 724, light sources 709 and photodetectors 710 and define the opening 717 into which the substrate 702 is inserted.

Figure 8 shows the main steps 825-826 of a method of making the wound monitoring apparatus described herein. As illustrated, the method generally comprises: forming the one or more fluid channels on or within the substrate between the wound region of the substrate and the detection region of the substrate to enable transfer of fluid from the wound region to the detection region 825; and forming the plurality of distinct sensing markers within the detection region of the substrate, each sensing marker configured to interact with the fluid transferred via the one or more fluid channels and undergo a detectable optical change in response to a different wound parameter 826.

Figure 9 shows the main steps 927-929 of a method of using the wound monitoring apparatus described herein. As illustrated, the method generally comprises: attaching the substrate to a human or animal body such that the wound region of the substrate is in fluid contact with a wound of the human or animal body 927; transferring fluid from the wound region of the substrate to the detection region of the substrate via the one or more fluid channels to enable interaction of the fluid with the plurality of sensing markers within the detection region of the substrate 928; and monitoring any optical change of the plurality of sensing markers in response to the different wound parameters 929.

Figure 10 illustrates schematically a computer/processor readable medium 1030 providing a computer program. The computer program may comprise computer code configured to perform, control or enable one or more of the method steps 825-826, 927-929 of Figure 8 and/or 9. In this example, the computer/processor readable medium 1030 is a disc such as a digital versatile disc (DVD) or a compact disc (CD). In other embodiments, the computer/processor readable medium 1030 may be any medium 1030 that has been programmed in such a way as to carry out an inventive function. The computer/processor readable medium may be a removable memory device such as a memory stick or memory card (SD, mini SD, micro SD or nano SD).

Other embodiments depicted in the figures have been provided with reference numerals that correspond to similarfeatures of earlier described embodiments. For example, feature number 1 can also correspond to numbers 101, 201, 301 etc. These numbered features may appear in the figures but may not have been directly referred to within the description of these particular embodiments. These have still been provided in the figures to aid understanding of the further embodiments, particularly in relation to the features of similar earlier described embodiments.

The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole, in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that the disclosed aspects/embodiments may consist of any such individual feature or combination of features. In view of the foregoing description it will be evident to a person skilled in the art that various modifications may be made within the scope of the disclosure.

Claims

Claims 1. A wound monitoring apparatus comprising a substrate having a wound region and a detection region connected to one another by one or more fluid channels configured to transfer fluid from the wound region to the detection region, the detection region comprising a plurality of distinct sensing markers each configured to interact with the fluid transferred via the one or more fluid channels and undergo a detectable optical change in response to a different wound parameter, wherein the plurality of sensing markers are tethered within the detection region of the substrate to inhibit removal of the sensing markers from the detection region by the fluid.
2. The apparatus of claim 1, wherein the plurality of sensing markers are configured to undergo a detectable optical change in response to two or more of the following wound parameters: oxygen, temperature, pH, moisture, an irritant and a pathogen.
3. The apparatus of claim 1 or 2, wherein each sensing marker is configured such that the optical change varies with the magnitude of the respective wound parameter.
4. The apparatus of any preceding claim, wherein each sensing marker comprises a chemical substance configured to undergo a reversible optical change upon interaction with the fluid.
5. The apparatus of any preceding claim, wherein the detection region comprises a plurality of reference markers for comparison with respective sensing markers to facilitate detection of the optical change.
6. The apparatus of claim 5, wherein each reference marker comprises the same material as the respective sensing marker, and is coated to prevent interaction of this material with the fluid.
7. The apparatus of claim 5 or 6, wherein each reference marker is positioned to avoid interaction with the fluid.
8. The apparatus of any preceding claim, wherein each sensing marker is one or more of physically and chemically tethered within the detection region.
9. The apparatus of any preceding claim, wherein the plurality of sensing markers are tethered to the substrate within the detection region.
10. The apparatus of any of claims 1 to 8, wherein the apparatus comprises a cover configured to overlay the substrate, and wherein the sensing markers are tethered to the underside of the cover such that the sensing markers are within the detection region when the cover is overlaid on the substrate.
11. The apparatus of claim 10 when dependent upon claim 5, wherein the reference markers are formed on the cover.
12. The apparatus of any preceding claim, wherein the substrate comprises a plurality of fluid channels configured to transfer fluid from the wound region to each sensing marker.
13. The apparatus of claim 12, wherein the plurality of fluid channels associated with each sensing marker are configured to have different transfer rates for the fluid.
14. The apparatus of claim 13, wherein the plurality of fluid channels associated with each sensing marker have one or more of different volumes, cross-sectional areas, and degrees of tapering to provide the different transfer rates for the fluid.
15. The apparatus of any preceding claim, wherein the substrate further comprises an absorbent region configured to absorb and retain the fluid following its interaction with the sensing markers to facilitate unidirectional transfer of the fluid from the wound region to the detection region.
16. The apparatus of any preceding claim, wherein the apparatus comprises one or more light sources configured to illuminate the plurality of sensing markers with light, and one or more photodetectors configured to detect light reflected from or transmitted through the plurality of sensing markers to enable detection of the optical change.
17. The apparatus of claim 16 when dependent upon claim 5, wherein the apparatus comprises one or more light sources configured to illuminate the plurality of reference markers with light, and one or more photodetectors configured to detect light reflected from or transmitted through the plurality of reference markers for comparison with the light reflected from or transmitted through the plurality of respective sensing markers to facilitate detection of the optical change.
18. The apparatus of claim 17, wherein the apparatus is configured such that each sensing marker shares a light source and photodetector with a respective reference 10 marker.
19. The apparatus of claim 16 when dependent upon claim 10, wherein one or more of the substrate and cover are optically transparent to facilitate detection of the light by the one or more photodetectors.
20. The apparatus of any of claims 16 to 19, wherein the one or more light sources and photodetectors are contained within a housing, and wherein the housing comprises an opening configured to releasably receive the substrate to enable detection of the optical change.
21. The apparatus of claim 20, wherein one or more of the substrate and housing are configured for attachment to a human or animal body to facilitate in-situ detection of the optical change.
22. The apparatus of claim 20 or 21, wherein the housing is configured to inhibit contact between the fluid and one or more of the light sources and photodetectors when the substrate is received via the opening in the housing.
23. The apparatus of claim 22, wherein the opening is dimensioned to inhibit contact between the fluid and one or more of the light sources and photodetectors; the light sources/photodetectors are positioned within the housing to inhibit contact between the fluid and one or more of the light sources and photodetectors; and/or the substrate is separated from the light sources/photodetectors by a fluid-impervious layer of material to inhibit contact between the fluid and one or more of the light sources and photodetectors.
24. The apparatus of any of claims 20 to 23, wherein the housing comprises circuitry configured to process a signal output by the one or more photodetectors to enable detection of the optical change.
25. The apparatus of any of claims 16 to 23, wherein the apparatus is configured to send a signal output by the one or more photodetectors to an external device to enable detection of the optical change.