PH and moisture indicator devices and formulations

Patent metadata

Field	Value
Publication number	US-12578318-B2
Application number	US-202117321270-A
Country	US
Kind code	B2
Filing date	May 14, 2021
Priority date	Jan 11, 2013
Publication date	Mar 17, 2026
Grant date	Mar 17, 2026

Abstract

Disclosed herein are devices, wound dressings and methods for determining the pH of fluid or a wound exudate at a wound. Example devices include a device comprising a surface configured to contact the fluid or wound and a pH indicator covalently bound thereto or applied to the surface, wherein the pH indicator has a first colour prior to contact with the fluid or the wound exudate and changes colour as a function of the pH of the fluid or wound exudate. Example devices include a device which indicates wound exudate loading within a wound dressing and wound dressing comprising an absorbent layer and a moisture indicator which indicates would exudate loading within the dressing, wherein the visibility of the moisture indictor changes as a result of a physical transformation of a first material within the dressing. Systems, devices, and methods are provided for monitoring wound status and progression by measuring pH levels indicated by pH-sensitive wound dressings. In some implementations, a wound is monitored by capturing an image of the pH-sensitive wound dressing and processing the captured image to determine the color of a pH indicator included on the wound dressing. The color of the indicator is determined in terms of RGB values from the image, and a pH value for the wound dressing is calculated from the dressing RGB values. The calculated pH value is then relayed to a user to be used as an indicator of wound status or health.

First claim

The invention claimed is:

1 . A wound dressing configured to indicate wound exudate loading, comprising:
an absorbent layer comprising a wound-facing side and a non-wound-facing side, the absorbent layer configured to absorb wound exudate and allow wound exudate to migrate through the absorbent layer to an indicator, the indicator positioned to be in contact with the non-wound-facing side of the absorbent layer, comprising:
a first composition configured to transform from a first state to a second state, each state having a different color; and
a second composition configured to dissolve upon contact with wound exudate and release ions to alter analyte levels within a portion of the wound exudate, the portion configured to transform the first composition from the first state to the second state upon contact, the transformation from the first state to the second state comprising a color change from a first color to a second color,
wherein the second composition is encapsulated in a soluble barrier configured to dissolve upon contact with wound exudate such that the second composition does not interact with the first composition until the soluble barrier is contacted by wound exudate; and
a spacer layer comprising a 3-D knitted spacer fabric material comprising a differential filament count configured to vertically transport wound exudate, the spacer layer positioned between the first composition and the second composition such that the spacer layer physically separates the first composition and the second composition such that the first and second compositions do not interact until wound exudate passes through the spacer layer.

2 . The wound dressing of claim 1 , wherein the ions comprise hydrogen or hydroxide ions.

3 . The wound dressing of claim 2 , wherein the ions comprise hydrogen ions.

4 . The wound dressing of claim 2 , wherein the ions comprise hydroxide ions.

5 . The wound dressing of claim 1 , wherein the first and second compositions are impregnated into different carrier materials within the wound dressing.

6 . The wound dressing of claim 1 , wherein the first and second compositions are impregnated into a single carrier material within the device.

7 . The wound dressing of claim 1 , wherein the absorbent layer has a peripheral edge and wherein the indicator extends outwardly from the peripheral edge.

8 . A wound dressing according to claim 7 , wherein the indicator extends from the peripheral edge to form an annular ring.

9 . The wound dressing of claim 1 , wherein the spacer layer is coated in a hydrophilic material.

10 . The wound dressing of claim 1 , wherein the spacer layer is configured to promote wound exudate transport between the carrier layers.

Assignees

• Smith & Nephew

Inventors

• Hartwell Edward Yerbury
• Hicks John Kenneth

Classifications

• G01N31/222

  for investigating moisture content · CPC title

• A61B5/0013

  Medical image data (A61B1/00011, A61B6/56, A61B8/56 take precedence) · CPC title

• A61B5/1495

  Calibrating or testing of in-vivo probes · CPC title

• A61B5/445

  Evaluating skin irritation or skin trauma, e.g. rash, eczema, wound, bed sore · CPC title

• A61F13/42

  with wetness indicator or alarm · CPC title