FIELD OF THE INVENTION

The present invention relates to a wound dressing, and, more specifically, to a wound dressing which provides wound exudate removal due to capillary forces.

BACKGROUND OF THE INVENTION

A dressing is an adjunct used by a person for application to a wound in order to promote healing and/or prevent further harm. Traditional wound dressings usually comprise a fabric or felt of absorptive material such as a gauze in direct contact with the wound. Such dressings are normally covered in order to avoid or reduce bacterial contamination but are not efficient in this respect. They have the general advantage of absorbing exudate from the wound but on the other hand, tend to stick to the wound surface, thus inhibiting healing. Often, exudate that has been removed from a wound recontaminates the wound. Furthermore, removal of the dressing is commonly painful where such sticking has taken place.

US patent 7070584 provides a ceramic foam dressing. The capillaries draw liquid through the dressing from the wound. However, the length of the capillaric pathway is long, and vulnerable to clogging, thereby limiting removal of suppurating liquid from the wound. Furthermore, ceramic dressings are frangible, making the total fluid removal effect unpredictable and in many cases inadequate and again, vulnerable to clogging. The clogged exudate will eventually become a source of serious bacterial contamination. In view of the above, there is a long term and unmet need to provide means and methods of continuously removing fresh wound exudate from a wound site, without danger of reinfecting the wound by contamination with old exudate and exudative debris.

SUMMARY

It is hence one object of the invention to disclose a biocompatible wound dressing shaped to conform to a wound site. The aforesaid dressing comprises a plurality of capillary-like pores. The dressing is adapted to be removably adhered to the wound in an air-tight way and remove exudate therefrom.

It is a core purpose of the invention to provide the capillary dressing provided by means of electrospinning. The dressing is characterized by porosity ranged between about 3 and about 50 microns.

Another object of the invention is to disclose the capillary dressing made of polymer fibers. The polymer is selected from the group consisting of polyurethane-silicon copolymer, Polyurethanecarbonate, Polycarbonate and any combination thereof.

A further object of the invention is to disclose the capillaries characterized by water suction height ranged between about 50 and about 150 mm.

A further object of the invention is to disclose the capillaries characterized by water suction productivity ranged between about 0.02 g-cm^-min ^"1 and 0.2 g-cm^-min ^"1 .

A further object of the invention is to disclose the capillaries characterized by protein suction productivity ranged between about 0.05 g-cm^-min ^"1 and 0.3 g-cm^-min ^"1 .

A further object of the invention is to disclose the capillary which is in a fluid communication with a pump providing air rarefaction in a wound area.

A further object of the invention is to disclose a method of removing an exudate from a patient's wound. The method comprises the steps of (a) providing a capillary wound dressing further comprising a plurality of capillary-like pores; the dressing adapted to be removably adhered to the wound in an air-tight way and remove exudate therefrom; (b) adhering the capillary dressing to the wound in an air-tight way; (c) removing said exudate from the wound.

The step of removing said exudate is performed by means capillary forces originated from capillary-like pores characterized by sizes ranged between about 50 and about 150 micron.

A further object of the invention is to disclose the step of providing the dressing further comprising a step of electrospinning polymer fibers. The fibers are selected from the group consisting of polyurethane-silicon copolymer fibers, Polyurethanecarbonate fibers,

Polycarbonate fibers and any combination thereof. A further object of the invention is to disclose the step of removing the exudate from the wound further comprising a step of vacuuming a wound area by means of a pump fluidly connected to the dressing.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to understand the invention and to see how it may be implemented in practice, a plurality of embodiments is adapted to now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which FIG. 1 is a schematic presentation of the experimental measurement of maximum height provided due to capillary water suction.

DETAILED DESCRIPTION OF THE INVENTION

The following description is provided, alongside all chapters of the present invention, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, are adapted to remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide a biocompatible wound dressing and a method of removing an exudate from a patient's wound.

In medicine, the term 'wound' hereinafter refers to a type of injury in which the skin is torn, cut or punctured (an open wound), or where blunt force trauma causes a contusion

(a closed wound).

The term 'dressing' hereinafter refers to an adjunct used by a person for application to a wound in order to promote healing and/or prevent further harm. A dressing is designed to be in direct contact with the wound.

The term 'exudate' hereinafter refers to any fluid that filters from the circulatory system into lesions or areas of inflammation. Its composition varies but generally includes water and the dissolved solutes of the blood, some or all plasma proteins, white blood cells, platelets and (in the case of local vascular damage) red blood cells.

In accordance with a preferred embodiment of the current invention, a biocompatible wound dressing is shaped to conform to a wound site. The aforesaid dressing comprises a plurality of capillary-like pores. The dressing is adapted to be removably adhered to the wound in an air-tight manner and remove fresh exudate continuously with little or no blocking. In order to achieve this, the dressing or at least the part of the dressing which comes into contact with the wound surface, is constructed of special electrospun material characterised by a plurality of capillary pores, which are effectively hollow capillary tubes, extending continuously from the surface of the wound (the lower surface of the dressing) to the upper surface of the dressing. The dressing facilitates the removal of fresh exudate, and the aforesaid dressing is characterized by porosity ranged between about 3 and about 50 microns.

In accordance with the current invention, the capillary dressing is made of polymer fibers. The polymer is selected from the group consisting of polyurethane-silicon copolymer, Polyurethanecarbonate, Polycarbonate and any combination thereof.

In accordance with a further embodiment of the current invention, the capillaries are characterized by water suction height ranged between about 50 and about 150 mm.

In accordance with a further embodiment of the current invention, the capillaries are characterized by water suction productivity ranged between about 0.02 g-cm^-min ^"1 and about 0.2 g-cm ^"2 -min ^" '.

In accordance with a further embodiment of the current invention, the capillaries are characterized by protein suction productivity ranged between about 0.05 g-cm^-min ^"1 and

0.3 g-cm^-min ^'1 .

In accordance with a further embodiment of the current invention, the capillary dressing is in a fluid communication with a pump providing air rarefaction (suction) over the wound area.

In accordance with a further embodiment of the current invention, a method of removing an exudate from a patient's wound comprising the steps of (a) providing a capillary wound dressing further comprising a plurality of capillary-like pores; the dressing adapted to be removably adhered to the wound in an air-tight way and remove exudate therefrom; (b) adhering said capillary dressing to the wound in an air-tight way; (c) removing the exudate from the wound. The step of removing the exudate is performed by means capillary forces originated from capillary-like pores characterized by sizes ranged between about 50 and about 150 micron.

In accordance with a further embodiment of the current invention, the step of providing the dressing further comprises a step of electrospinning polymer fibers. The fibers are selected from the group consisting of polyurethane-silicon copolymer fibers,

Polyurethanecarbonate fibers, Polycarbonate fibers and any combination thereof.

In accordance with a further embodiment of the current invention, the step of removing the exudate from the wound further comprises a step of vacuuming a wound area by means of a pump fluidly connected to the dressing.

The proposed technical solution is experimentally tested. Standard samples of electrospun dressings with dimensions of 2*40 mm ² were produced. The samples were made of following polymers: Polyurethane-Silicon Copolymer, Polyurethanecarbonate, and Polycarbonate. The following parameters were measured: Average Pore Size, Water

Suction Max Height, Water Suction Productivity, and Protein Suction Productivity. The obtained experimental data are presented in Table I. The size of sample pores was determined according to a method of capillary flow.

Reference is now made to Figure 1, presenting an experimental setup for measuring water suction maximum height. Specifically, one terminal of an electrospun dressing 20 is immersed into water accommodated in a bath 10. A holder 30 hangs another terminal of the dressing 20 over the bath 10. The water accommodated in a bath 10 flows up due to capillary forces up to a height H.

TABLE 1