Wound therapy system and wound dressing with ph sensor
A wound therapy system having a wound dressing for treating a wound includes a sensor that measures a pH level at a wound area. The sensor has a circuit that includes a first electrode and one or more second electrodes. The first electrode has a changeable conductivity that changes according to a hydrogen ion concentration level. The one or more second electrodes are configured with a fixed conductivity that does not change with the hydrogen ion concentration level. The first electrode is coated with a porous protective membrane formed from a sulfonated and/or carboxylated copolymer.
1 . A sensor for measuring a pH level in a wound therapy system, the sensor comprising:
a circuit configured to measure a pH level of a wound fluid from a wound area, the circuit comprising:
a substrate having a first end and an opposite second end;
a first electrode printed on the first end of the substrate and comprising a material having a changeable conductivity that changes according to a hydrogen ion concentration level;
a second electrode printed on the first end of the substrate and comprising a material having a fixed conductivity that does not change with the hydrogen ion concentration level;
a porous protective membrane coating covering the first electrode, the porous protective membrane coating comprising a sulfonated and/or carboxylated copolymer and being configured to permit hydrogen ion passage from the wound fluid to the first electrode while preventing direct contact between the wound fluid and the first electrode;
a third electrode printed on the second end of the substrate and being electrically connected to the first electrode via a first electrical trace; and
a fourth electrode printed on the second end of the substrate and being electrically connected to the second electrode via a second electrical trace,
wherein the circuit measures the pH level by measuring one or more voltage values between the third electrode and the fourth electrode.
2 . The sensor of claim 1 , wherein the sulfonated and/or carboxylated copolymer comprises a sulfonated tetrafluoroethylene based fluoropolymer-copolymer, and wherein the porous protective membrane coating excludes chitosan.
3 . The sensor of claim 2 , wherein the porous protective membrane coating comprises tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer.
4 . The sensor of claim 1 , wherein the first electrode and the second electrode are printed in close proximity to each other on the first end of the substrate using screen-printing technology, wherein the first electrode and the second electrode are printed on the same side of the substrate, and wherein the substrate comprises a polymeric material.
5 . The sensor of claim 4 , wherein the first electrode comprises a carbon-based ink or paste printed on the first end of the substrate and iridium oxide electrodeposited on top of the carbon-based ink or paste.
6 . The sensor of claim 4 , further comprising a sealing portion formed on a periphery of the first end of the substrate, wherein the sealing portion is an unprinted portion of the substrate and is made of an adhesive material configured to seal the first end of the substrate to one or more components of the wound therapy system.
7 . The sensor of claim 4 , further comprising an isolation ink layer that separates and protects the first, second, third, and fourth electrodes such that the first and second electrodes can be directly exposed to the wound fluid while the third and fourth electrodes are prevented from being exposed to the wound fluid.
8 . The sensor of claim 4 , wherein the first electrode has a circular shape, and wherein the second electrode partially surrounds the first electrode.
9 . The sensor of claim 1 , wherein the first electrode comprises iridium oxide and the second electrode comprises silver chloride.
10 . A wound treatment system having a sensor for measuring a pH level of a wound fluid from a wound area, the system comprising:
a wound dressing comprising:
a wound fluid manifold layer overlying the wound area and configured to permit and distribute a flow of wound fluid from the wound area,
a drape layer disposed over the wound fluid manifold layer, and
a tubing connection pad disposed on and connected to the drape layer;
a negative pressure therapy unit configured to provide a negative pressure at the wound area;
tubing coupling the negative pressure therapy unit to the tubing connection pad; and
a sensor configured to measure a pH of the wound fluid from the wound area, the sensor coupled to the tubing connection pad and in fluid communication with the wound fluid from the wound area, the sensor comprising:
a substrate having a first end and an opposite second end;
a first electrode printed on the first end of the substrate and comprising a material having a changeable conductivity that changes according to a hydrogen ion concentration level, the first electrode being covered with a porous protective membrane coating comprising a sulfonated and/or carboxylated copolymer and being configured to permit hydrogen ion passage from the wound fluid to the first electrode while preventing direct contact between the wound fluid and the first electrode;
a second electrode printed on the first end of the substrate and comprising a material having a fixed conductivity that does not change with the hydrogen ion concentration level;
a third electrode printed on the second end of the substrate and being electrically connected to the first electrode via a first electrical trace; and
a fourth electrode printed on the second end of the substrate and being electrically connected to the second electrode via a second electrical trace,
wherein the sensor measures the pH level by measuring one or more voltage values between the third electrode and the fourth electrode.
11 . The system of claim 10 , wherein the porous protective membrane coating comprises a sulfonated tetrafluoroethylene based fluoropolymer-copolymer, and wherein the porous protective membrane coating excludes chitosan.
12 . The system of claim 10 , wherein the porous protective membrane coating comprises tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer.
13 . The system of claim 10 , wherein the first electrode and the second electrode are printed on the first end of the substrate using screen-printing technology, wherein the first electrode and the second electrode are printed on the same side of the substrate, and wherein the substrate comprises a polymeric material.
14 . The system of claim 13 , further comprising a sealing portion formed on a periphery of the first end of the substrate, wherein the sealing portion is an unprinted portion of the substrate and is made of an adhesive material configured to seal the first end of the substrate to one or more components of the wound therapy system.
15 . The system of claim 13 , wherein the first electrode is printed on the first end of the substrate with a carbon-based ink or paste, and wherein iridium oxide is electrodeposited on top of the carbon-based ink or paste.
16 . A method of fabricating a sensor for measuring a pH level at a wound area, the method comprising:
screen-printing a carbon-based ink or paste on a first end of a substrate comprising a polymeric material;
depositing iridium oxide on the carbon-based ink or paste by electrodeposition to form a first electrode having a changeable conductivity that changes according to a hydrogen ion concentration level;
depositing a porous protective membrane coating on the first electrode wherein the porous protective membrane coating comprises a sulfonated and/or carboxylated copolymer;
screen-printing a second electrode on the first end of the substrate, wherein the second electrode comprises a material having a fixed conductivity that does not change according to a hydrogen ion concentration level;
screen printing a third electrode on an opposite second end of the substrate such that the third electrode is electrically connected to the first electrode via a first electrical trace; and
screen printing a fourth electrode on the second end of the substrate such that the fourth electrode is electrically connected to the second electrode via a second electrical trace,
wherein the circuit measures the pH level by measuring one or more voltage values between the third electrode and the fourth electrode.
17 . The method of claim 16 , wherein the porous protective membrane coating is deposited on the first electrode by applying an aqueous solution comprising the sulfonated and/or carboxylated copolymer thereto, wherein the sulfonated and/or carboxylated copolymer comprises about 5% by weight of the aqueous solution.
18 . The method of claim 16 , wherein the sulfonated and/or carboxylated copolymer comprises tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer.
19 . The method of claim 16 , further comprising curing the aqueous solution using an evaporation process.