PH AND MOISTURE INDICATOR DEVICES AND FORMULATIONS
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.
1 . A device for determining the pH of a fluid, the device comprising a fluid-contacting surface having a pH indicator covalently immobilised thereon, wherein the pH indicator has a first colour prior to contact with the fluid and changes colour as a function of the pH of the fluid.
2 . The device according to claim 1 , wherein the colour change in the pH indicator is detectable at a 0.1 unit interval change in pH.
3 . The device according to claim 2 , wherein the colour change in the pH indicator is detectable between about pH 5 and about pH 10.
4 . The device according to claim 3 , wherein the colour change in the pH indicator is detectable between about pH 5.5 and about pH 9.5.
5 . The device according to claim 3 , wherein the colour change in the pH indicator is detectable between about pH 6.5 and 9.5.
6 . The device according to claim 1 , wherein the pH indicator comprises aphenylazo compound.
7 . The device according to claim 6 , wherein the phenylazo compound is selected from the group listed in Table 1.
8 . The device according to claim 6 , wherein the pH indicator comprises a combination of phenylazo compounds.
9 . The device according to claim 1 , wherein the device comprises a cellulosic material.
10 . A device comprising:
(a) a fluid-contacting surface,
(b) an opposing non-fluid contacting surface,
(c) a pH indication zone comprising a pH indicator covalently bound therein, which indicates the pH of a fluid, wherein the colour of the pH indicator changes in response to a change in the pH of the fluid; and,
(d) at least one conduit for directing fluid towards the pH indication zone.
11 . The device according to claim 10 , wherein the device has an outer surface and wherein a pH indication zone is located at or near the outer surface.
12 . The device according to claim 11 , wherein the device has a peripheral edge extending between the fluid-contacting surface and the opposing non-fluid contacting surface and wherein the outer surface is the peripheral edge.
13 . The device according to claim 10 , wherein the at least one conduit directs fluid laterally towards the pH indication zone.
14 . The device according to claim 10 , wherein the colour change in the pH indicator is detectable at a 0.1 unit interval change in pH.
15 . The device according to claim 14 , wherein the colour change in the pH indicator is detectable between about pH 5 and about pH 10.
16 . The device according to claim 15 , wherein the colour change in the pH indicator is detectable between about pH 5.5 and about pH 9.5.
17 . The device according to claim 15 , wherein the colour change in the pH indicator is detectable between about pH 6.5 and about pH 9.5.
18 . The fluid dressing according to claim 10 , wherein the pH indicator comprises a phenylazo compound.
19 . The device according to claim 18 , wherein the phenylazo compound is selected from the group listed in Table 1.
20 . The device according to claim 18 , wherein the pH indicator comprises a combination of phenylazo compounds.
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