Yarns, fibers or filaments, textile article, and medical device obtained from said yarns for skin cicatrization

Abstract

The subject of the present invention is yarns, fibers or filaments and also a textile article and a medical device obtained from said yarns, for improving skin cicatrization, in particular by activating collagen synthesis at the surface of the injured skin. The yarns, fibers or filaments of the invention comprise a polymeric matrix and inorganic fillers, uniformly dispersed in the polymeric matrix, having properties of absorption and/or of emission in the 2-20 μm far-infrared region.

Claims

1. A method for improving skin cicatrization, the method comprising applying to the injured part of the skin yarns, fibers or filaments having a linear mass of 1.2 dtex comprising a polymeric matrix, said polymeric matrix being polyamide 66, and particulate inorganic fillers, said particulate inorganic fillers being uniformly dispersed in said polymeric matrix, having a weight average particle size of from 0.2 to 1.5 μm, and having properties of absorption and/or emission in the far-infrared region ranging from 2 μm to 20 μm, thereby improving skin cicatrization; wherein said yarns, fibers or filaments contain 1.5% by weight titanium dioxide, 0.5% by weight barium sulfate, and 0.2% by weight tourmaline.

2. The method according to claim 1, wherein the yarns, fibers or filaments stimulate collagen synthesis.

3. The method according to claim 1, wherein a textile article comprises said yarns, fibers or filaments.

4. The method according to claim 3, wherein the textile article is a fabric, a knit, or a nonwoven.

5. The method according to claim 4, wherein the textile article is a bandage or a garment.

6. The method according to claim 1, wherein a non-implantable medical device comprises said yarns, fibers or filaments.

7. The method according to claim 6, wherein the non-implantable medical device is a dressing or a suture thread.

8. The method according to claim 1, wherein the particulate inorganic fillers have a particle size distribution wherein 99% by weight of the particles have a size of less than 1.0 μm and 90% by weight of the particles have a size of less than 0.5 μm.

9. The method according to claim 1 wherein the ratio of the average diameter of the filaments to the weight average particle size of the particulate inorganic fillers is greater than 10 and less than 200.

Description

EXAMPLES

Example 1

(1) 1. Polymeric Composition Preparation

(2) A masterbatch of polyamide 66 is prepared by incorporating 20% by weight of infrared-emitting inorganic fillers in powder form into polyamide 66 with a relative viscosity (VR) of 43, measured in a solution of formic acid at 90% in water.

(3) The resulting masterbatch is extruded, cooled and granulated.

(4) The resulting granules are remelted and then introduced during spinning into molten polyamide 66 with a relative viscosity (VR) of 43, measured in a solution of formic acid at 90% in water, in a proportion which makes it possible to obtain the desired amount of inorganic fillers in the polymer matrix. 2. Polymer Spinning and Fabric Preparation

(5) The molten polymeric composition obtained is spun at a temperature of between 280° C. and 300° C. (measured in the die), air-cooled (20° C., relative humidity of 65%) and wound at a speed of 4200 m/min so as to obtain a continuous multifilament yarn. The multifilament yarn made up of 68 filaments with a circular cross section was subsequently textured. The titer of the filament in the final product is 1.2 dtex.

(6) In the example of the invention, a yarn of polyamide 66 containing 1.5% by weight of TiO.sub.2 with a weight-average particle size of 0.3 μm, 0.5% by weight of BaSO.sub.4 with a weight-average particle size of 0.25 μm and 0.2% by weight of tourmaline with a weight-average particle size of 0.3 μm was prepared.

(7) The resulting yarn is then converted into knits using a circular knitting machine.

(8) By way of comparison, a multifilament yarn was also prepared from a virgin polyamide 66 (containing only 1.5% by weight of TiO.sub.2 with a weight-average particle size of 0.3 μm) with a relative viscosity (VR) of 43, measured in a solution of formic acid at 90% in water. The comparative yarn is also made up of 68 filaments with a circular cross section and was subsequently textured. The titer of the filament in the final product is 1.2 dtex. The resulting yarn is also converted into knits using the same circular knitting machine.

(9) Bermuda shorts were subsequently produced from said knits. The bermuda shorts have a surface density of 305 g/m.sup.2, and contain 12% of spandex. These articles were subsequently used to evaluate the effectiveness in the application envisaged (cf. in vivo tests below). 3. In Vitro Tests:

(10) In order to evaluate the effect due to the presence of the fabric according to the invention on collagen synthesis, an in vitro method which was described in the literature (Carlson, M A, Longaker, M T. Wound Repair and Regeneration, 12(2):134-47, 2004 March-April) and validated by specialists in the field was used. This method consists in using fibroblast-populated collagen matrix (MCFP) as an in vitro experimental model of healing, since this gives a reasonable approximation of wound cicatrization during the established granulation tissue phases.

(11) According to the MCFP model, a solution of collagen type I and of primary fibroblasts is added to a cell culture. This solution polymerizes at physiological pH and at a temperature of 37° C., giving rise to a gel, and then the medium supplemented with growth factors or with serum is added.

(12) The fibroblasts were obtained from the normal skin of five volunteers. The evaluation of the fibroblast samples from each volunteer was carried out eight times. The results given below are an average of these evaluations.

(13) The fibroblasts were maintained under defined temperature and oxygen saturation conditions (37° C. and 5% of CO.sub.2) for seven days.

(14) The same model was constructed in the presence of external light. After seven days of culture, the Petri dishes were photographed using the UTSCSA Image Tool for Windows version 3 software, and the surface of each gel was measured, making it possible to calculate the level of contraction of the gel.

(15) The method previously described makes it possible to observe the level of contraction of the gel, which makes it possible to evaluate the collagen synthesis activity by the fibroblasts. Indeed, the greater the contraction of the gel, the greater the collagen synthesis.

(16) The gel contraction results after seven days are described in table 1 below.

(17) TABLE-US-00001 TABLE 1 Increase in gel contraction after seven days Increase in contraction (relative to a contraction Fabric used without fabric) Fabric of example 1 +21% Comparative fabric  +1%

(18) Conclusion: It is noted that the degree of contraction of the gel, when it is in contact with the fabric of the invention, is much greater than that observed with the comparative fabric. Thus, collagen synthesis is significantly increased in the presence of the fabric of the invention. 4. In Vivo Tests:

(19) In order to evaluate collagen synthesis in vivo, a study was carried out with a group of 15 volunteer women who wore bermuda shorts made with yarn according to the invention for one leg and the comparative polyamide yarn for the other leg.

(20) The bermuda shorts are in direct contact with the skin.

(21) After 60 consecutive days of using the bermuda shorts at a rate of six hours per day, an evaluation of the amount of collagen type I (the most present in the skin) in the skin was set up. The results given below are an average of these evaluations.

(22) Human skin exhibits a maximum level of fluorescence excitation at a wavelength of 295 nm and of fluorescence emission at 360 nm. This fluorescence is attributed to the aromatic side chain of the amino acid tryptophan present in the protein structures of the skin. Another excitation maximum is observed at the wavelength of 340 nm and a fluorescence emission at 400 nm. This other maximum is attributed to the cross-links of collagen type I.

(23) The method chosen is measurement by fluorescence spectroscopy, which makes it possible to quantify the presence of collagen type I in the skin by comparing the amount of tryptophan (reference measured at 360 nm) with the amount of collagen cross-links (measured at 400 nm).

(24) The intensity of the tryptophan signal in the excitation spectrum at 295 nm is strongly linked to cell proliferation. A reduction in the intensity of the signal at 295 nm indicates a reduction in epidermal proliferation associated with skin aging.

(25) Internal (intrinsic) aging of the skin shows a 10 to 20% reduction in the signal for tryptophan and collagen type I every 10 years.

(26) Taking into account the short duration of the test, the tryptophan signal was considered to be a virtually constant internal reference during the study.

(27) The ratio between the intensities of the signals at 340 nm and 295 nm (I.sub.340/I.sub.295) indicates the increase in the number of collagen type I cross-links, resulting from the increase in the synthesis of this molecule.

(28) The results of the quantification of the collagen synthesis are given in table 2 below.

(29) TABLE-US-00002 TABLE 2 Increase in collagen (%) Sample Increase after 60 days Fabric of example 1 5.9% Comparative fabric 0.9%

(30) The statistical test shows that there is a statistically significant difference between the fabric according to the invention and the comparative fabric from the point of view of the increase in collagen synthesis in vivo (p<0.0001).

(31) The above two tests in vitro and in vivo confirm that the contact of the yarn supplemented with additive according to the invention, with the skin, makes it possible to observe a significant increase in collagen synthesis.

(32) As is already commonly accepted by the scientific community, collagen synthesis plays an important role in the skin cicatrization process, and the increase in collagen synthesis contributes significantly to the quality and the speed of cicatrization.