Ultrasound-permeable surgical patch / bandage

Abstract

The present invention relates to a surgical patch / bandage (1) which comprises a cellulose layer (2), a polyvinyl chloride (PVC) layer (3), a polyethylene oxide (PEO) layer (4), where the cellulose layer (2) is an outer layer of the surgical patch / bandage (1). The surgical patch / bandage is permeable to ultrasound.

Description

[0001] TECHNICAL DESCRIPTION

[0002] ULTRASOUND-PERMEABLE SURGICAL PATCH / BANDAGE

[0003] Technical field

[0004] The present invention belongs to the field of hygiene, and in particular to the field of surgical patches / bandages. Specifically, the present invention relates to a surgical patch / bandage which is permeable to ultrasound and may exhibit antimicrobial activity.

[0005] State of the art

[0006] Surgical patches / bandages are a known means widely used in wound treatment, e.g. for the protection of wounds from external influences or for the absorption of exudates. There are various kinds of surgical patches / bandages distinguished by their fabrication material, e.g. cotton or plastic or composite. Also, surgical patches / bandages may exhibit antimicrobial activity, e.g. due to incorporation of an antibacterial agent. In general, surgical patches / bandages present varying properties depending on their fabrication material.

[0007] However, surgical patches / bandages in the state of the art present various disadvantages associated with their structure. First, they are easily impregnated and inconvenient for the patients bearing them. Also, they stick to the skin and hair and their removal is painful. Furthermore, they can be easily contaminated if they have no antimicrobial agent. Another important feature is that they are opaque when on a wound, and thus a doctor cannot evaluate the condition of the wound. Due to their light blockage, they are also impermeable to ultrasound, thus preventing ultrasound imaging. Consequently diagnosis will be delayed, the doctor is obliged to use costly imaging techniques such as CT scan and magnetic tomography, while there is also danger for wound contamination by the ultrasound gel.

[0008] Summary of the invention

[0009] The invention aims at solving at least some of the above-mentioned disadvantages of a surgical patch / bandage of the state of the art, and in particular the lack of ultrasound permeability, so that imaging examinations may be performed without removing the patch / bandage from the wound. Also, a surgical patch / bandage would be advantageous to exhibit antimicrobial activity and thus provide protection against contamination.

[0010] Therefore the present invention provides a surgical patch / bandage which comprises a cellulose layer, a polyvinyl chloride (PVC) layer, and a polyethylene oxide (PEO) layer, the cellulose layer being an outer layer of the surgical patch / bandage.

[0011] In an embodiment of the invention, the cellulose layer optionally includes one or more of collagen, silicone and polyethylene oxide.

[0012] In a further embodiment, the cellulose layer contains 0-50 %w / w collagen, and / or 0-50 %w / w silicone and / or 0-50 %w / w polyethylene oxide.

[0013] In a further embodiment, the cellulose layer optionally includes an antimicrobial agent selected from one or more of silver nanoparticles at 0-1 %w / w, povidone-iodine solution at 0-1 %w / w, quantum dots at 0-1 %w / w, and antibacterial gel at 0-1 %w / w. In an embodiment of the invention, the PVC layer of the surgical patch / bandage optionally includes one or more of silicone, collagen and acrylonitrile-butadiene-styrene (ABS) resin.

[0014] In a further embodiment, the PVC layer contains silicone at 0-50 %w / w, and / or collagen at 0-50 %w / w and / or acrylonitrile-butadiene-styrene (ABS) resin at 0-50 %w / w.

[0015] In an embodiment of the invention, the polyethylene oxide layer of the surgical patch / bandage optionally includes an antimicrobial agent selected from one or more of antibacterial gel, silver nanoparticles and iodine solution.

[0016] In a further embodiment, the polyethylene oxide layer contains the antibacterial gel at 0-1 %w / w, and / or the silver nanoparticles at 0-1 %w / w, and / or the iodine solution as a povidone-iodine solution at 0-1 %w / w.

[0017] The collagen optionally contained in the cellulose layer and in the PVC layer may be the same or different.

[0018] Similarly, the silicone optionally contained in the cellulose layer and the PVC layer may be the same or different.

[0019] The antibacterial gel optionally contained in the cellulose layer and the polyethylene oxide layer may be the same or different.

[0020] As regards the arrangement of the three basic layers of the surgical patch / bandage, this may vary. However, the cellulose layer is in all cases an outer layer, since upon application the surgical patch / bandage will be positioned on the patient’s body from the side of the cellulose layer. On the contrary, the polyvinyl chloride (PVC) layer may be arranged between the polyethylene oxide (PEO) layer and the cellulose layer, or otherwise the polyethylene oxide (PEO) layer may be arranged between the polyvinyl chloride (PVC) layer and the cellulose layer.

[0021] An advantage of the invention is that the surgical patch / bandage is ultrasound-permeable and thus ultrasound imaging may be performed without removal thereof. Also, in various embodiments it presents antimicrobial activity, is fluid-repellent and biodegradable. Also, it aids in wound healing and is easily detached from the patient’s skin without pain.

[0022] Brief description of the figure

[0023] Figure 1 shows a schematic lateral cross-section of the structure of an embodiment of the surgical patch / bandage of the invention.

[0024] Description of a preferred embodiment

[0025] At first, it should be noted that the quantitative data in %w / w given above and hereinafter for any material refers, unless otherwise specified, to the percentage by weight of the said material in respect of the weight of the basic layer on or in which the material is included.

[0026] Figure 1 shows schematically an embodiment of the surgical patch / bandage (1) of the present invention. This comprises a cellulose layer (2), a polyvinyl chloride (PVC) layer (3) and a polyethylene oxide (PEO) layer (4), arranged one on top of the other along their length. In the specific embodiment, the polyvinyl chloride (3) layer has on a first side thereof an attached cellulose layer (2) and on a second side -opposite to the first side- an attached polyethylene oxide layer (4). During its use, the surgical patch / bandage (1) is placed on a biological tissue or patient (5) from the free side of the cellulose layer (2). The application of ultrasound via an ultrasound imaging equipment (6) may be performed from the free side of the polyethylene oxide layer (4).

[0027] The linking of the layers between them may be performed by drip casting, vortexing of the cast mixture and evaporation of the respective solvents. For example, on the cellulose layer (2) a mixture of polyvinyl chloride in a suitable organic solvent may be firstly applied by drip casting, then the cast mixture is vortexed to spread completely and uniformly on the cellulose layer (2) and thereafter the solvent of the polyvinyl chloride mixture is allowed to evaporate, thereby leaving a polyvinyl chloride layer (3) on the cellulose layer (2). Thereafter, in an analogous manner a mixture of polyethylene oxide in a suitable organic solvent will be applied on the polyvinyl chloride layer (3) and a similar procedure will be followed to obtain the polyethylene oxide layer (4).

[0028] It should be noted that when a basic layer, i.e. the cellulose layer, the polyvinyl chloride layer or the polyethylene oxide layer, is to be applied on an already available other of the basic layers which has optional components mentioned hereinabove and hereinbelow in the detailed description, the application of the basic layer to be applied is effected after the application of the optional components in / on the already available basic layer is completed. This means that the layer to be applied may not be directly in contact with the already available basic layer, but may be in contact with a layer of optional component of the already available basic layer.

[0029] The cellulose layer (2) comprises fibers of variable size and may have a

[0030] Young modulus of 2-40 MPa, a tensile strength of 2-10 MPa and a tearing energy of 50-1000 KJ / m2. The thickness of the cellulose layer may be 1-10 mm in order to absorb wound excretions and sweat. The cellulose layer (2) may contain 0-50 %w / w silicone, 0-50 %w / w PEO, 0-50 %W / \N collagen, preferably 40-50 %\N!\N silicone, 30-40 %w / w PEO, 0-2 %w / w collagen.

[0031] In the cellulose layer (2), silicone may be applied as layer and may advantageously consist in PDMS Sylgard 184 or 186 and RTV4420 or 4528. These silicone layers have a tearing energy of 70-920 J / m2and a Young modulus of 2-40 MPa. The thickness of the silicone layer may be 0.1-5 mm. Covalent linking of the silicone layer to the cellulose layer (2) is performed by short-UV plasma treatment.

[0032] The cellulose layer (2) may be surface-modified by polyethylene oxide (PEO, Mw=3000-20000 Da). In this regard, polyethylene oxide may be modified with thiol groups, and then cellulose may be linked to the thiol-modified polyethylene oxide, without significant changes in the layer thickness.

[0033] The cellulose layer (2) may also include a collagen membrane of 0.1-2 mm thickness from bovine collagen type I with a solids content of 2-10% (2-10 mg / ml) and thickness 20-500 um. The layers have a tearing energy, which depends on the length, in the range of 0.01 to 0.1 J / m, whereas the Young modulus is similar to that of cellulose at 2-40 MPa. In order to form the collagen layer, on the cellulose membrane (2) a neutralized bovine collagen solution is applied by vortex casting and left to gel under controlled temperature (25-40 °C).

[0034] Optional additives in the cellulose layer (2) include 0-1 %w / w silver nanoparticles, 0-1 %w / w iodine solution as povidone-iodine solution, 0-1 %w / w quantum dots or 0-1 %w / w antibacterial gel. A surgical patch / bandage (1) of the invention, in which the cellulose layer (2) contains these additives, also presents antimicrobial activity.

[0035] For the production of the antibacterial gel, cellulose derivatives may be used, for example hydroxyethyl cellulose (HEC), sodium carboxymethylcellulose (CMC), hydroxypropyl methyl cellulose (HPMC). These are impregnated by an aqueous solution of ethanol, isopropanol or povidone-iodine (30-70%) and are swollen to form a gel of thickness 0.1-10 mm and viscosity 800-60,000 MPa*s. An example of an antibacterial gel composition comprises hydroxypropyl methyl cellulose (HPMC, 1261 g / mol) (0.5-2 %w / w) and hydroxyethyl cellulose (HEC, 736.7 g / mol) (0.5-2 %w / w) in an aqueous phase having a high content in ethanol (50-70 %w / w) and glycerol 0.2-2 %w / w, the percentages referring to the weight of the composition.

[0036] Quantum dots constitute a category of materials consisting of particles having a size of the order of nanometers, which have numerous applications, among which their use as antimicrobial agents. In the present invention, quantum dots include, for example but not limiting to, graphene quantum dots, CdSe quantum dots, etc.

[0037] The application of the antibacterial gel, silver nanoparticles and povidone- iodine solution may be effected in a manner similar to that described above, i.e. by application thereof in the form of a solution or dispersion in a suitable solvent, vortexing to effect uniform spreading on the cellulose layer (2) and evaporation of the solvent so that the antibacterial gel, the silver nanoparticles and the povidone-iodine complex remain attached in / on the cellulose layer (2).

[0038] On the cellulose layer (2), a PVC layer (3) has been applied. The PVC layer is formed on the cellulose layer (2) in manner similar to that described above, by drip casting a 50-80 %w / w mixture in a suitable solvent, the percentage referring to the weight of the mixture. The PVC layer (3) itself may include 0-50 %w / w silicone, 0-50 %w / w collagen and 0-50 %w / w acrylonitrile-butadiene- styrene polymer (ABS). As silicone, pre-polymerized silicone (BioLSR M130 or LSRM125) may be used. For example, the pre-polymerized silicone (BioLSR M130 or LSRM125) is applied and spread on the PVC layer and then left to solidify and form an elastic layer by vulcanization at room temperature or by UV radiation.

[0039] The application of collagen on the PVC layer (3) may be performed by applying a neutralized collagen solution (e.g. bovine collagen) by vortex casting and then allowing suitable time for a collagen gel to form under controlled temperature (25-40 °C).

[0040] The application of the acrylonitrile-butadiene-styrene (ABS) polymer on the PVC layer may be effected by drip casting of a solution of the polymer in a suitable solvent, vortexing and evaporation of the solvent to form a polymer layer.

[0041] On the free side of the polyvinyl chloride layer (3), a polyethylene oxide layer (4) has been applied. The application of the polyethylene oxide layer (4) is performed in the manner described above, i.e. by drip casting of a mixture of polyethylene oxide in a suitable solvent, vortexing of the cast mixture to spread uniformly on the polyvinyl chloride layer (3) and evaporation of the solvent to form the polyethylene oxide layer (4).

[0042] The PEO layer (4) may further contain 0-1 %w / w antibacterial gel, 0-1 %w / w silver nanoparticles, and 0-1 %w / w iodine solution in the form of povidone- iodine solution (BETADINE®). Having these additives, the PEO layer (4) of the surgical patch / bandage (1) of the present invention presents antimicrobial activity. For the production of the antibacterial gel, cellulose derivatives may be used, for example hydroxyethyl cellulose (HEC), sodium carboxymethylcellulose (CMC), hydroxypropyl methyl cellulose (HPMC). These are impregnated with an aqueous solution of ethanol, isopropanol or povidone-iodine (30-70%) and swollen to form a gel having a thickness of 0.1-10 mm and viscosity of 800- 60,000 (mPa*s). An example of an antibacterial gel composition includes hydroxypropyl methyl cellulose (HPMC, 1261 g / mol) (0.5-2 %w / w), and hydroxyethyl cellulose (HEC, 736.7 g / mol) (0.5-2 %w / w) in an aqueous phase having a high content in ethanol (50-70 %w / w) and glycerol at 0.2-2 %w / w, the percentages referring to the weight of the composition.

[0043] The application of the antibacterial gel, the silver nanoparticles and the povidone-iodine solution may be effected in a manner similar to that described above, i.e. by the application thereof in the form of a solution or dispersion, vortexing to spread them uniformly on the PEO layer (4) and evaporation of the solvent so that the antibacterial gel, the silver nanoparticles and the povidone- iodine complex remain attached in / on the PEO layer (4).

[0044] A surgical patch / bandage of the invention was tested on a human patient in order to evaluate its permeability to ultrasound. The tests were performed with an ultrasound imaging system (General Electric Logiq P9 model 2021). Ultrasound images were obtained at a selected site on the hand of the patient, and then the surgical patch / bandage of the invention was applied thereon. Images were then obtained after the application of the patch / bandage, and the obtained images before / after application were compared between them.

[0045] It was established that after the application of the surgical patch / bandage of the invention, the ultrasound images remained intact and satisfactory, without changes in the associated technical factors, e.g. Tissue harmonic imaging (THI) and the Tis index (Thermal index for small tissues). Similarly, during the test, no change in technical parameters determining image quality was required. For example, ultrasound frequency, the gain which characterizes how dark or bright the image is, the dynamic range characterizing the difference between maximum and minimum value of the provided signal or the Speckle Reduction Imaging algorithm remained unaltered.

Claims

CLAIMS1. A surgical patch / bandage (1) comprising a cellulose layer (2), a polyvinyl chloride (PVC) layer (3) and a polyethylene oxide (PEO) layer (4), the cellulose layer (2) being an outer layer of the surgical patch / bandage (1).

2. A surgical patch / bandage (1 ) according to claim 1 , wherein the cellulose layer (2) includes one or more of collagen at 0-50 %w / w, silicone at 0-50 %w / w and polyethylene oxide at 0-50 %\NI\N.

3. A surgical patch / bandage (1) according to anyone of claims 1 or 2, wherein the cellulose layer (2) includes silver nanoparticles at 0-1 %w / w, povidone-iodine solution at 0-1 %w / w, quantum dots at 0-1 %w / w, and antibacterial gel at 0-1 %w / w.

4. A surgical patch / bandage (1) according to anyone of the previous claims, wherein the PVC layer (3) includes one or more of silicone at 0-50 %w / w, collagen at 0-50 %w / w and acrylonitrile-butadiene-styrene (ABS) resin at 0-50 %w / w.

5. A surgical patch / bandage (1) according to anyone of the previous claims, wherein the polyethylene oxide layer (4) includes one or more of antibacterial gel at 0-1 %w / w, silver nanoparticles at 0-1 %w / w and povidone- iodine solution at 0-1 %w / w.

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