WOUND CARE PRODUCT WITH INTEGRATED SENSOR TECHNOLOGY FOR DETERMINING WOUND DATA

The invention relates to a wound dressing in which sensor technology can be integrated for detecting wound data such as pH value, moisture and temperature as well as data relating to the condition of the wound dressing itself.

The invention relates to a wound dressing in which sensors for recording wound data such as pH, moisture, and temperature and also data on the condition of the wound dressing itself can be integrated. The wound dressing comprises a cover layer, at least one foam-containing layer, a wound-contact layer, and at least one textile-based fabric containing at least one sensor. Such a wound dressing can be used for chronic wounds, for example. With this dressing it is possible, by means of the at least one sensor, to continuously collect information in the form of sensor data both on the condition of the wound and on the condition of the wound dressing itself.

The healing of skin wounds is based on the ability of the skin to regenerate epithelial and also connective and supporting tissues. Regeneration itself is characterized by a complex process of interconnecting cell activities that gradually drive the healing process forward. Thus, the literature describes three fundamental phases of wound healing irrespective of wound type. These include the inflammatory or exudative phase for hemostasis and wound cleansing (phase 1, cleansing phase), the proliferative phase for the formation of granulation tissue (phase 2, granulation phase), and the differentiation phase for epithelization and cicatrization (phase 3, epithelization phase).

A wound is understood as meaning a parting of the tissues that envelope the body in humans or animals. It may be associated with a loss of substance.

Chronic wounds are a particularly difficult type of wound to treat and are characterized inter alia by showing only very little or no healing even after a treatment period of eight to ten weeks. Such wounds can accordingly require months of treatment. The associated dressing changes can thus cause a patient pain time and again over a long period of time. The resulting severe reduction in quality of life means that the physical suffering is often accompanied by mental suffering too, which can cause distress to the patient.

Monitoring the wound beds of chronic wounds and the condition of the wound dressing can be one way of helping improve treatment, of long-term patients in particular, since this increases the safety of treatment and can make it possible to avoid frequent dressing changes. By continuously recording wound parameters, such monitoring can also offer the opportunity to conduct more intensive research into wound healing processes.

Monitoring based on the use as sensors of electronic components having rigid housings can cause such housings to exert point pressure on the wound when pressing down, which can cause the patient pain. However, the use of conventional flexible sensors does not always provide adequate resolutions, with the result that reliable measurement results often cannot be obtained.

WO 2017/195038 A1 describes a wound dressing comprising at least one essentially flexible substrate, said substrate bearing one or more sensors. More particularly, a wound dressing is described in which it is possible to integrate a film-based substrate, on the surface of which is printed/mounted at least one sensor for monitoring wound data. Such a wound dressing appears to have scope for improvement as regards the possibility of absorbency and the application of the sensors.

An object of the present invention is to overcome the disadvantages of the prior art and to further improve the treatment of wounds and of chronic wounds in particular. In particular, the present invention should have an advantageous influence on wound healing in the epithelization or regeneration phase, thereby making it possible for example to shorten the duration of treatment and/or lessen scarring. In addition, the present invention should provide a wound-care product that makes it possible to maximize the efficacy of treatment. Moreover, the treatment should not be perceived as unpleasant by the patient, so that high patient compliance (adherence to the treatment instructions by the patient) is achieved. Pain during dressing changes should be reduced to the absolute minimum. It should also be possible to apply the wound-care product in an advantageous manner.

The objects were unexpectedly achieved by a multilayer (multi-ply) wound-care product having specially integrated sensors for recording wound parameters and the condition of the wound-care product itself. In addition, the structure of the wound-care product of the invention makes it possible for the data/information logged by the sensors to be recorded in a minimally invasive manner.

EXAMPLES

Example 1: Constituents of the Wound Dressing of the Invention

1(a) The cover layer is for example a polyurethane film having a thickness of 25 μm such as Platilon U073 from Covestro.

1(b) The foam-containing layer is for example a polyurethane foam having a thickness of about 3 mm obtainable for example by the reaction of Baymedix FD103 and AD111.

1(c) The wound-contact layer is for example a perforated multilayer silicone layer (Acrysil150from Advanced Silicone Coating S.A.S.) or a silicone web having a thickness of 150 μm.

1(d) The at least one textile-based fabric containing a sensor can be produced for example as a warp-knit fabric on a Comez609crochet galloon machine, it being possible for the sensor to be integrated by means of weft insertion technology. For this, a conductive thread as sensor and a yarn for production of the warp-knit fabric can be used with the following parameters given by way of example: The conductive thread is an enameled copper wire from Superior Essex (USA) having a diameter of 50 μm, which has a polyurethane insulating layer with a thickness of 0.02 μm. The yarn is a polyester yarn (TWD PES f48) from TWD Fibres GmbH (Germany).

The sensor yarn was produced by the DITF (German Institute for Textile Research, Denkendorf) research institute. A textile-based fabric of this kind containing a sensor is shown inFIG.1. The sensor yarn (1) shown inFIG.1was produced by the DITF (German Institute for Textile Research, Denkendorf) research institute.FIG.2shows an excerpt fromFIG.1and a light microscope image thereof.

Example 2: Structure of a Wound Dressing of the Invention

FIG.3shows the top view of a wound dressing of the invention, in which the island form of the wound dressing can be seen.

Example 2a:FIG.4shows the cross-sectional view of a schematic structure of a wound dressing of the invention along the IV-IV line ofFIG.3. The figure shows how the textile-based fabric containing a sensor (“sensor knit”) (d) is arranged on a silicone mesh serving as a wound-contact layer (c). Positioned on the sensor knit is a polyurethane foam as a foam-containing layer (b), with a polyurethane film as cover layer (a) arranged thereabove. Av denotes a reading device.

Example 2b:FIG.5shows the cross-sectional view of a schematic structure of a wound dressing of the invention along the IV-IV line ofFIG.3. The figure shows how a polyurethane foam as a foam-containing layer (b) is arranged on a silicone mesh serving as a wound-contact layer (c), the foam-containing layer (b) including a sensor-containing textile-based fabric. Arranged above the foam-containing layer (b) is a polyurethane film as a cover layer (a). Av denotes a reading device.

Example 3: Determination of the Absorption Capacity of a Foam by Means of a Sensor Contained in a Textile-Based Fabric

3.1 For determination of the absorption capacity (“filling level”) of two foams having a thickness of 3 mm, a sensor contained in a textile-based fabric is integrated into each of the foams.FIG.6shows the two test foams E-4A and E-4B (top) and a schematic structure thereof (bottom).

The capacity is then determined at maximum absorption. This is done by testing the free absorption capacity of the sample in accordance with DIN EN 13726-1. In a departure from the standard, the associated electrical capacitance value is included in the weight value after 30 minutes of free absorption in a test solution prescribed in the DIN that was determined here. This first test gives the maximum absorption capacity [g], which corresponds to an absorption capacity (filling level) of 100% and the associated electrical capacitance value. In the test that follows, the absorption curve (filling level trajectory) is determined. This is done by discontinuously loading the sample over a certain time interval (in this case approx. 45 minutes) with the same amount of a test fluid at exact intervals of one minute, until the previously determined absorption capacity (=100% filling level) is reached. The weight and electrical capacitance value each minute are dated. From the weight value, the filling level is determined and the corresponding capacity value assigned. The corresponding diagrams are shown inFIG.7. As can be seen from the diagrams, from about 70% of the absorption capacity in the case of for example sample E-4A (upper figure) and from about 80% for sample E-4B (lower figure) the electrical capacitance no longer increases strongly but stagnates. From this it can be inferred that the absorption capacity of the foam is (almost) exhausted and the need for a change is imminent.

3.2 For determination of the absorption capacity (“filling level”) of the foam, a sensor contained in a textile-based fabric is arranged between a silicone layer (which may correspond to the wound-contact layer) and a foam. The absorption capacity (filling level) of the foam (in %) and electrical capacitance of the sensor (in nF) are then determined in the same way as described above. The corresponding diagram is shown inFIG.8. As can be seen from the diagram, the capacitance of the sensor comes up against a threshold value from which it can be inferred that the absorption capacity of the foam is (almost) exhausted and the need for a change is imminent.

3.3 For determination of the absorption capacity (“filling level”) of the foam, a sensor contained in a textile-based fabric is arranged between a film cover (which may correspond to the cover layer) and a foam. The filling level (in %) and capacitance of the sensor (in nF) are then determined in the same way as described above. The corresponding diagram is shown inFIG.9. As can be seen from the diagram, above a certain threshold value the capacitance increases further only slowly and approaches a threshold value from which it can be inferred that the absorption capacity of the foam is (almost) exhausted and the need for a change is imminent.