ANTIMICROBIAL TEXTILES AND METHODS FOR PRODUCTION OF THE SAME

Abstract

A method for making an antibacterial fabric having resistance to laundering while maintaining its antibacterial properties.

Claims

1) A process for producing antibacterial fabric that retains its antibacterial properties over twenty-five launderings, comprising the steps of: a) immersing the fabric in a solution of glyxol, eugenol and water; b) squeezing the solution out of the fabric c) curing the wetted fabric under heat; and d) drying the cured fabric.

2) A fabric made according to claim 1 wherein the solution comprises ethanol.

3) A fabric made according to claim 1 wherein the solution comprises ethyl acetate.

4) A fabric made according to of claim 1 comprising cotton and polyester.

5) A fabric made according to claim 1 comprising a blend of cotton and polyester.

6) A fabric made according to claim 5 wherein the blend is 75% polyester.

7) A fabric made according to claim 5 wherein the blend is 50% polyester.

8) A fabric made according to claim 1 wherein the solution comprises about 10 grams of glyxol per liter of solution, and about 1 gram of eugenol per liter of solution.

9) A fabric made according to claim 2 wherein the ethanol is present in an amount of about 10 percent of the water by volume.

10) A fabric made according to claim 3 wherein the ethyl acetate is present in an amount of about 10 percent of the water by volume.

11) A process for producing a MRSA-resistant fabric that retains 4-7 log reduction in MRSA growth thereon after up to twenty-five launderings, comprising the steps of: a) immersing the fabric in a solution of glyxol, eugenol and water; b) squeezing the solution out of the fabric c) curing the wetted fabric under heat; and d) drying the cured fabric.

Description

DESCRIPTION OF THE INVENTION

[0014] 25% cotton, 75% polyester fabrics in several variations optimize antimicrobial property activity retention. These fabrics are treated with aqueous solutions including glyxol (as a bonding agent for an active natural bicidal), eugenol (as an active natural bicidal), and in most cases polyvinyl alcohol (as a second bonding agent for the active natural bicidal). Typical amounts of these reagents have been from 10 to 100 grams of glyxol, 1-10 grams of polyvinyl alcohol and 1 to 15 grams of eungenol, all per liter of water.

[0015] It has now been determined that of the two bonding agents initially used, namely polyvinyl alcohol and glyxol, the polyvinyl alcohol has little or no measurable effect on retention of bioactivity by the fabric. The remaining bonding component, namely glyxol, has the desirable characteristic that it can be heated and still result in a biocidally active fabric being created.

[0016] Some of the water component of the fabric treatment solution can be replaced with other liquids, namely either 10% ethanol or 10% ethyl acetate (both measured as parts by weight of the solution), and still retain a 4-7 log reduction in growth of S. aureus (MRSA), B. cereus (model for anthrax) and M. smegmatis (model for TB).

[0017] Three fabrics, namely fabric treated with a 10:10:100 ratio of polyvinyl alcohol, glyxol and water by volume, fabric treated with the same ratio of polyvinyl alcohol, glyxol and water by volume with the glyxol being heated, and fabric treated with a 10:100 ratio of glyxol to water and having no polyvinyl alcohol, were also assayed for launderability, namely whether the fabrics retained their antimicrobial properties after being laundered.

[0018] All three fabrics were laundered between three (3) and six (6) times without loss of antimicrobial viability.

[0019] 50% cotton 50% polyester fabrics were also treated using with a 10:10:100 ratio of polyvinyl alcohol, glyxol and water by volume, with some variations of the bonding components, namely polyvinyl alcohol and glyxol, including deletion (separately) of each of these components and heating of the polyvinyl alcohol prior to addition to the treatment mixture.

[0020] Optimization of the amount of biocide, namely eugenol, that is added to the solution applied to the fabric revealed that one gram of eugenol per liter of solution may be used without loss of antibacterial activity.

[0021] Based on feedback from the above bactericidal evaluations, one aspect of this treats the 25:75% cotton:polyester fabrics, while another aspect optimizes the treatment. The treatment to impart antimicrobial properties can be applied to the fabric with common textile wet processing equipment, whereas earlier treatments (as disclosed in the patent applications noted above that have been incorporated by reference) while effective utilized a 100:1 liquid mix to fabric ratio. (As used herein a 100:1 liquid mix to fabric ratio means one (1) gram of fabric to ninety-nine (99) milliliters of treatment solution.)

[0022] In one of its embodiments the invention decreases that to a 10:1 ratio, with no loss of bicidal efficacy. Additionally, it is within the scope of the invention to remove one component, namely polyvinyl alcohol, from the treatment, with minimal adverse effect on the bactericidal properties of the fabric. This is beneficial, as the polyvinyl alcohol has the tendency to alter the hand and stiffness of the treated fabric. In a further aspect of the invention, the use of a single bonding agent, namely glyxol, may be reduced by 25%, namely 25 grams, (from an earlier 100% or 100 grams), with the treated fabric still retaining bicidal activity that persists over at least 25 washes using either a cold wash and cold dry cycle, or a hot wash and hot dry cycle.

[0023] Further, the inventive treatment has been found to kill nine separate and common hospital-acquired human pathogens namely S. aureus (MRSA), B. cereus (model for anthrax), M. smegmatis (model for TB), vancomycin-resistant Enterococcus faecalis (VRE), Pseudomonas aeruginosa, Streptococcus pneumoniae, S. agalacticae, S. pyogenes and S. epidermidis.

[0024] The method of the invention has been proven effective in the treatment of bioactively-coated white coats made of a 65%:35% polyester-cotton blend fabric. The treatment is retained by the coats through at least 10 washes in hot water with high heat drying. Cost of the antibacterial treatment in accordance with the invention is 50% lower than costs cited in the literature, including those treatments disclosed in the three published United States patent applications incorporated by reference above, due to the optimization of the bonding agent(s) and bioactive agent(s).

[0025] Antimicrobial textiles comprising cotton-polyester blends of 25-75% synthetic-cotton blend have been successful. In creating the successful 75:25 antibacterial fabric, several methods may be employed in accordance with the invention including altering the concentrations of polyvinyl alcohol and replacing the water component of the treatment with either ethanol or ethyl acetate. The invention also embraces heating the polyvinyl alcohol component prior to application to the fabric. Fabrics were also treated and tested without glyxol. As can be seen from FIG. 1 and Table 1, all treatments, except those lacking glyxol in the recipe, produced an effective binding of the biocide, namely the eugenol, to the fabric resulting in a 4-5 log reduction in growth, i.e. the fabrics were bactericidal against Staphylococcus aureus (MRSA strain), Bacillus cereus and Mycobacterium smegmatis.

TABLE-US-00001 TABLE 1 Effect of fabric treatments on antibacterial activity of fabric Percentage Reduction from Control (log unit change in parentheses) S. aureus (MRSA B. cereus (spore M. smegmatis (TB Treatment 1 strain) producer) model) 1 99.99% (4 log units) 99.99% (5 logs) 99.99% (5 logs) 2 99.99% (4 log units) 99.99% (5 logs) 99.99% (5 logs) Heated polyvinyl alcohol 99.99% (4 log units) 99.99% (5 logs) 99.99% (5 logs) No polyvinyl alcohol 99.99% (5 log units) 99.99% (6 logs) 99.99% (5 logs) 10% ethanol 99.99% (4 log units) 99.99% (5 logs) 99.99% (4 logs) 10% ethyl acetate 99.99% (4 log units) 99.99% (5 logs) 99.99% (5 logs) No glyxol 50% (<than 1 log unit) 31% (<than 1 log unit) 62% (<than 1 log unit)

[0026] The effective concentration of the eugenol biocide was tested at concentrations ranging from 1 gram of eugenol per liter of treatment solution up to 10 grams of eugenol per liter of treatment solution using the remaining bonding agent and a 50% : 50% cotton-polyester fabric. As can be seen from FIG. 2, in which the efficacy of the fabric was tested against S. aureus (MRSA) strain, all concentrations were able to reduce the normal growth of the bacterium (shown as the control or no fabric point) by at least 4 logs, i.e. the fabrics were bactericidal. Similar data was also obtained using B. cereus and M. smegmatis.

[0027] The bonding agent was tested at concentrations varying from 5% (10:0:5) to 100% (10:0:100 fabric) using the 25:75% cotton-polyester fabric and a 10 grams per liter of solution of biocide. As can be seen from FIG. 3, in which the efficacy of this created fabric was tested against S. aureus (MRSA) strain, after 5 washes in cold water and drying, all concentrations above 25% were able to reduce the normal growth of the bacterium (shown as control, i.e. no fabric present) by at least 4 logs, i.e. where bactericidal and the biological activity of the fabric could be retained through 5 washes. Concentrations of 5% and 10% were initially bactericidal but the bonding agent was of too low a level to hold the active bicidal to the fabric and so after 4 washes the activity became bacteriostatic at 10%, i.e. the fabric prevented the bacteria from multiplying.

[0028] Durability of 25:75% cotton-polyester textiles post laundering lead to use of the previously noted use of a solution with the 10:10:100 ratio of polyvinyl alcohol, glyxol and water by volume but without the apparently unnecessary bonding component (as previously explained). Although lower concentrations of the bonding agent may be utilized, in one preferred embodment the invention retaines the maximum concentration but decreases the biocide to a 10:1 dilution. As can be seen from Table 2, the created fabrics were laundered 10 times in hot water and high heat dried without loss of antibacterial killing efficacy against S. aureus (MRSA), B. cereus or M. smegmatis.

TABLE-US-00002 TABLE 2 Evaluation of bacterial range of biocidal 25:75 cotton-polyester fabric Number of (*= No growth at a 10.sup.7 dilution of medium) washes MRSA B. cer. M. smeg. P. aer. VRE S. epi. S. agal. S. pneum. S. pyo. 0 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (unwashed) (5 logs) (7 logs) (5 logs) (7 logs) (4 logs) (5 logs (5 logs) (6 logs) (5 logs) 1 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (4 logs) (4 logs) (5 logs) (5 logs) (5 logs) (6 logs) (5 logs) (6 logs) (5 logs) 2 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (4 logs) (5 logs) (5 logs) (5 logs) (6 logs) (5 logs) (6 logs) (4 logs) 3 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (5 logs) (4 logs) (4 logs) (4 logs) (4 logs) (5 logs) (4 logs) (4 logs) 4 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (4 logs) (5 logs) (4 logs) (4 logs) (4 logs) (5 logs) (5 logs) (4 logs) 5 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (4 logs) (5 logs) (4 logs) (4 logs) (4 logs) (5 logs) (6 logs) (4 logs) 6 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (4 logs) (5 logs) (4 logs) (5 logs) (4 logs) (5 logs) (4 logs) (5 logs) 7 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% *99.99% (5 logs) (4 logs) (5 logs) (5 logs) (5 logs) (4 logs) (4 logs) (5 logs) >7 logs 8 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% *99.99% (5 logs) (4 logs) (4 logs) (5 logs) (5 logs) (5 logs) (4 logs) (4 logs) >7 logs 9 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (4 logs) (5 logs) (5 logs) (4 logs) (4 logs) (5 logs) (6 logs) (4 logs) 10 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% *99.99% (5 logs) (4 logs) (5 logs) (4 logs) (4 logs) (4 logs) (5 logs) (5 logs) >7 logs

[0029] In accordance with the invention the number of washed may be increased to 25, without loss of activity against the normal growth (shown as control (0) point on graph) of S. aureus (MRSA), as can be seen in FIG. 4.

[0030] Visually the FIG. 4 data can be seen in the photograph presented as FIG. 5. Control at 10.sup.12 is shown top left, bottom left is 20 washes and bottom right 25 washes. All quantitative fabric data are obtained using a 10.sup.8 dilution of the broth, i.e. 4 logs lower than the control.

[0031] Evaluation of narrow spectrum antimicrobial efficiency (AATCC-100 for quantitative analysis using MRSA, B.cereus and M. smegmatis) using six replicates, achieved a reduction in microbial growth of 99.99%.

[0032] Unwashed samples of three of the treated effective fabrics as identified above have each been tested on 6 separate occasions in duplicate against S. aureus (MRSA), B. cereus and M. smegmatis. Variations in the assay are small, with all effective fabrics exhibiting a range of 4-7 log inhibition of bacterial growth after a 24 hour culture, i.e. achieving bactericidal ability. Data are shown in Table 3 below as percentage as well as log reduction in bacterial growth.

TABLE-US-00003 TABLE 3 Replication of antibacterial Treatment fabric assay Replicate Number Number 1 2 3 4 5 6 S. aureus (MRSA) 1 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (4 logs) (4 logs) (4 logs) (4 logs) (4 logs) (4 logs) 10% ethanol 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (4 logs) (4 logs) (5 logs) (4 logs) (4 logs) 10% ethyl 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% acetate (4 logs) (4 logs) (4 logs) (4 logs) (4 logs) (4 logs) No polyvinyl 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% alcohol (4 logs) (5 logs) (5 logs) (5 logs) (5 logs) (4 logs) B. cereus 1 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (6 logs) (4 logs) (4 logs) (4 logs) (4 logs) 10% ethanol 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (5 logs) (4 logs) (4 logs) (4 logs) (4 logs) 10% ethyl 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% acetate (4 logs) (4 logs) (4 logs) (4 logs) (4 logs) (4 logs) No polyvinyl 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% alcohol (6 logs) (6 logs) (5 logs) (5 logs) (5 logs) (5 logs) M. smegmatis 1 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (5 logs) (5 logs) (4 logs) (6 logs) (6 logs) (6 logs) 10% ethanol 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% (4 logs) (6 logs) (6 logs) (5 logs) (5 logs) (6 logs) 10% ethyl 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% acetate (5 logs) (4 logs) (4 logs) (6 logs) (5 logs) (6 logs) No polyvinyl 99.99% 99.99% 99.99% 99.99% 99.99% 99.99% alcohol (5 logs) (6 logs) (5 logs) (5 logs) (7 logs) (7 logs)

[0033] Evaluation of the spectrum of antimicrobial efficiency (AATCC-100 for quantitative analysis using MRSA, B.cereus, M. smegmatis, Pseudomonas aeruginosa, vancomycin-resistant Enterococcus faecalis (VRE), Streptococcus epidermidis, S. agalacticae, S. pneumoniae, S. pyogenes and Clostridium difficile) showed that all nine bacterial species investigated displayed a 4-7 log reduction in growth after 24 hours of exposure to the biocide-treated fabric, as per the data presented in Table 4.

TABLE-US-00004 TABLE 4 Effect of fabric treatments on antibacterial activity of fabric Percentage Reduction from Control (log unit change in parentheses) B. cereus (spore M. smegmatis (TB Treatment Number S. aureus (MRSA strain) producer) model) 1 99.99% (4 logs) 99.99% (4 log units) 99.99% (5 logs) 2 99.99% (4 logs) 99.99% (5 log units) 99.99% (5 logs) 3 99.99% (5 log units) 99.99% (5 log units) 99.99% (5 logs) No polyvinyl alcohol 99.99% (4 log units) 99.99% (5 log units) 99.99% (5 logs) 10% ethanol 99.99% (4 log units) 99.99% (5 log units) 99.99% (5 logs) 10% ethanol 99.99% (4 log units) 99.99% (5 log units) 99.99% (5 logs) No glyxol 50% (less than 1 log unit) NT NT

[0034] Referring to FIG. 6, S. agalacticae quantitative data on blood agar with 25% cotton fabric were washed up to 10 times on high heat and high heat drying. Active colonies are apparent as shown in FIG. 6 with clear regions around them and appear almost as holes. In FIG. 6 the top left is the control at 10.sup.12, the right is washed 10, the bottom left is fabric washed 5 and the bottom right is unwashed. All quantitative fabric data were obtained using a 10.sup.8 dilution of the broth i.e. 4 logs lower than the control.

[0035] The invention further embraces treatment and use of 50% cotton-50% polyester fabrics. The scope of the invention includes varying two bonding components of the mixture and, as can be seen similarly to the 25% cotton 75% polyester fabric, the polyvinyl alcohol component is not always necessary for effective binding of the eugenol biocide.

[0036] Visually, these appear as shown in FIG. 7 with S. aureus (MRSA) control plates on the upper left and fabric treatments 1-4 respectively.

[0037] Durability data has been obtained using treatment 1 and on 50:50 fabric created with treatment 1 and without component 1. As can be seen in Tables 5 and 6, these fabrics can be laundered in cold water and low temperature air dried up to 6 times and up to 10 times in hot water with high heat drying, respectively, without loss of activity against S. aureus (MRSA), B, cereus and M. smegmatis.

TABLE-US-00005 TABLE 5 Launderability of treatment 1 50:50 fabric Percentage Reduction from Control (log unit change in parentheses) Number of S. aureus (MRSA B. cereus (spore M. smegmatis washes strain) producer) (TB model) 0 (unwashed) 99.99% (4 logs) 99.99% (5 logs.) 99.99% (5 logs) 1 99.99% (4 logs) 99.99% (5 logs) 99.99% (6 logs) 2 99.99% (4 logs) 99.99% (4 logs) 99.99% (5 logs) 3 99.99% (5 logs) 99.99% (5 logs) 99.99% (4 logs) 4 99.99% (4 logs) 99.99% (5 logs) 99.99% (4 logs) 5 Air (dry) 99.99% (5 logs) 99.99% (4 logs) 99.99% (5 logs) 5 Low (dry) 99.99% (4 logs) 99.99% (5 logs) 99.99% (4 logs) 6 Air (dry) 99.99% (4 logs) 99.99% (4 logs) 99.99% (5 logs) 6 Low (dry) 99.99% (4 logs) 99.99% (5 logs) 99.99% (4 logs)

TABLE-US-00006 TABLE 6 Launderability of 50:50 fabric created without component 1 Percentage Reduction from Control (log unit change in parentheses) Number of S. aureus (MRSA B. cereus (spore M. smegmatis washes strain) producer) (TB model) 0 (unwashed) 99.99% (4 logs) 99.99% (5 logs) 99.99% (5 logs) 1 99.99% (4 logs) 99.99% (4 logs) 99.99% (3 logs) 2 99.99% (5 logs) 99.99% (4 logs) 99.99% (4 logs) 3 99.99% (4 logs) 99.99% (4 logs) 99.99% (5 logs) 4 99.99% (4 logs) 99.99% (4 logs) 99.99% (5 logs) 5 99.99% (4 logs) 99.99% (4 logs) 99.99% (5 logs) 6 99.99% (4 logs) 99.99% (4 logs) 99.99% (4 logs) 7 99.99% (4 logs) 99.99% (4 logs) 99.99% (5 logs) 8 99.99% (5 logs) 99.99% (4 logs) 99.99% (4 logs) 9 99.99% (4 logs) 99.99% (5 logs) 99.99% (4 logs) 10 99.99% (4 logs) 99.99% (4 logs) 99.99% (4 logs)

[0038] Lab coats containing 65% polyester were treated. Several tests have been performed as to the antibacterial stability of the coats. The first was to examine whether abrasion affected the durability of the biocide binding to the fabric. Abrasion was performed after the coat material was treated using the now standard method i.e. with only one bonding agent and using the standard ASTM-D966 abrasion treatment with 2,500, 5,000, 7,500 or 10,000 cycles. Additional fabric was also treated and not abraded. Thereafter all material samples were washed up to 10 times using a warm wash and medium heat dry, according to manufacturer's instructions. The ability of the coats to remain antibacterial has been validated in full using the S. aureus MRSA strain, to date and in part (namely with a single wash) with B. cereus and M. smegmatis. The antimicrobial property producing treatment, in the absence of abrasion, is stable to up to 10 washes, but higher numbers of abrasion cycles (>5,000 cycles) are deleterious to the fabric, changing it from bactericidal to bacteriostatic (4 logs to 3 logs in terms of growth of the bacterium). The data from this are shown in Table 7.

TABLE-US-00007 TABLE 7 Effect of ASTM-D966 Abrasion Treatment on biocidal Abraded and capacity of 65:35 polyester-cotton fabric Percentage non-abraded Reduction from Control (log unit change in parentheses) fabrics S. aureus B. cereus M. smegmatis Abraded (MRSA strain) (spore producer) (TB model) Washed 1 2,500 cycles 99.99% (4 logs) 5,000 cycles 99.99% (5 logs) 7,500 cycles 99.99% (4 logs) 10,000 cycles 99.99% (4 logs) Washed 5 2,500 cycles 99.99% (4 logs) 5,000 cycles 99.0% (3 logs) 7,500 cycles 99.0% (3 logs) 10,000 cycles 99.0% (3 logs) Washed 10 2,500 cycles 99.99% (4 logs) 5,000 cycles 99.99% (4 logs) 7,500 cycles 99.99% (4 logs) 10,000 cycles 99.0% (3 logs) Non-abraded Washed 1 99.99% (5 logs) 99.99% (5 logs) 99.99% (5 logs) Washed 5 99.99% (4 logs) Washed 10 99.99% (4 logs)

[0039] FIG. 8 shows qualitative data on Clostridium sporogenes. This bacterium is a direct analog for botulism, shows 80% spore homology with C. difficile and about 60% genetic morphology. The plate shows 15, 20 and 25 washes with rings of no growth around the fabric.

[0040] FIG. 9 shows growth media after 24 hour incubation. On the left is the control, which shows cloudiness due to the presence of bacteria in the medium. On the right is the fabric washed 25 times. You can see the fabric at the bottom of the test tube. Note the clarity of the medium compared with the control.

[0041] FIG. 10 shows c sporogenes quantitative data. Control at 10.sup.12 is shown left and at right the 15 wash at 10.sup.8. Below are 20 washes and 25 washes also at 10.sup.8 dilution. All quantitative fabric data are obtained using a 10.sup.8 dilution of the broth i.e. 4 logs lower than the control.