SILVER-LOADED CELLULOSIC FIBERS WITH ANTI-FUNGAL AND ANTIBACTERIAL PROPERTIES – NEW BIO-ACTIVE FIBERS FOR INTELLIGENT TEXTILES: SEACELL® ACTIVE

Joachim W. Fluhr, Christina Hipler, Peter Elsner
Department of Dermatology, Friedrich-Schiller-University Jena, D-07740 Jena,
Germany

ABSTRACT

The skin is the interface between the body and the sometimes harsh environment. Each skin type has a specific skin physiology and is more or less adapted for protection against multiple stress factors. Textiles on the ot her hand are the tissues with the longest contact to the human skin. They play a critical role especially in skin conditions with an increased rate of bacterial and fungal infections like atopic dermatitis, hyperhidrosis, diabetic patients and aged skin. The results of the present study demonstrate the antifungal and antibacterial effect of SeaCell® Active in an in vitro test system against Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis and Candida krusei. Furthermore we could demonstrate antibacterial activity of fibres with different amounts of SeaCell® Active fibres in a dose-dependent manner against Staphylococcus aureus and Escherichia coli. Thus this fiber seems to be suited for bio-active textiles in specific anatomical body regions and skin conditions with a susceptibility for fungal and bacterial infections namely with Candida species, Staphylococcus aureus and Escherichia coli. For example bed sheets and shirts for patients with atopic dermatitis, socks for persons with transpiration problems or long-term exposure to tightly closed shoes, underwear for diabetic patients and patients with obesity as well as sportswear, occupational textiles as well as home textiles e.g. for allergic patients and hygiene products.

1. INTRODUCTION
1.1. Skin as an interface between body and environment
The skin is the interface between the body and the sometimes harsh environment. Each skin type has a specific skin physiology and is more or less adapted for protection against multiple stress factors. Textiles on the other hand are the tissues with the longest contact to the human skin. They play a critical role especially in skin conditions with an increased rate of bacterial and fungal infections like atopic dermatitis, hyperhidrosis, diabetic patients and aged skin.

1.2. SeaCell® Active: Intelligent solution for functional textiles
The increasing demand for “intelligent” and “bio-active” textiles inspired the German companies Zimmer AG, Frankfurt, and Alceru Schwarza, Rudolstadt to develop a revolutionary new fiber called SeaCell® Active. The natural, cellulose and seaweed based SeaCell® fibers served as a functional carrier for the active compound silver, which is known for more than one century to exert antifungal and antibacterial activity (Figure 1).

The cellulose-based, seaweed incorporated and silver loaded Lyocell fiber SeaCell® Active contains the minerals calcium, magnesium and sodium, which are known to play a key role in skin homeostasis. Figure 2 gives an example of a tissue with 100% SeaCell® active fibres.

The following compositions were tested:
SCA 100: SeaCell® Active 100%
SCA 100nw: SeaCell® Active 100% non-woven
SCA 5 -20: SeaCell® Active 5% - 20%
LC 100: Lyocell
SC 100: SeaCell®

w: washed fibre

2. ANTIFUNGAL PROPERTIES

2.1. Aim of the study
The present study was intended to test whether Sea Cell® with different amounts of the active silver fibre exert anti-fungal properties. We were interested in testing the anti-fungal activity against several different fungi from the Candida family: Candida albicans, Candida parapsilosis, Candida glabrata, Candida tropicalis and Candida krusei. Candida albicans, is responsible for a widely encountered itching skin infection with yeasts especially in skin folds. These fungal infections are associated with warm, moist and occlusive conditions e.g. under the armpits, under the breasts as well as in the genital and anal regions. Figure 3A and 3B give some clinical examples of infections with Candida albicans in the interdigital and genital (child) region.

Figure 3A and 3B: Dermal infection with Candida albicans in the interdigital (A) and genital (B) region .

2.2 Testing for antifungal activity in vitro
Two different in vitro test system were used: First a classical incubation of standard strains with different fibres was performed over 24 hrs. The results for these tests are shown in Figures 4-6. The antifungal effect was quantified in a Neubauer cellcounting chamber. Additionally a staining with a new fluorescent dye (FUN-1) was done: A new family of fluorescent probes has been developed for assessing the viability and metabolic activity of fungi. This class of d yes is exemplified by the FUN-1 stain, a membrane-permeant nucleic acid-binding dye that has been found to give rise to cylindrical intravacuolar structures (CIVS) in fungi. Biochemical processing of the dye by active cells yielded CIVS that were markedly red shifted in fluorescence emission and therefore spectrally distinct from the nucleic acid-bound form of the dye.

The present study revealed an excellent antifungal activity against different fungi from the Candida family namely Candida albicans (Figure 4), Candida glabrata, Candida krusei (Figure 5) and Candida tropicalis (Figure 6). Other Candida species like C. parapsilosis (onychomycosis), C. glabrata (genital infection), C. tropicalis and C. krusei were also susceptible against the SeaCell® Active fibers (data not shown). The most striking result was the dose-dependant manner (percentage of SeaCell® Active fibers in the tissue) of the antifungal activity against all. These results were confirmed by the new FUN-1 staining (Figure 7).

Figure 4: Antifungal activity against Candida albicans of different fibres in a dose dependant manner. Highest antifungal activity was detected for Sea Cell® Active 100% (SCA 100 and SCA 100 nw=non woven) A C.krusei ATCC 6258 B C.krusei ATCC 6258

Figure 5: Antifungal activity against Candida krusei of different fibres in a dose dependant manner. Highest antifungal activity was detected for SeaCell® Active 100% (SCA 100 and SCA 100 nw=non woven)

Figure 6: Antifungal activity against Candida tropicalis of different fibres. Highest antifungal activity was detected for Sea Cell® Active 100% (SCA 100)

Figure 7: Staining with fluorescent dyes (FUN-1):Baseline staining showed biochemically active fungi while 100% Sea Cell® Active treatment killed almost all living Candida albicans and Candida krusei

3. ANTIBACTERIAL PROPERTIES

Figure 8: Dermal bacterial infection with Staphylococcus aureus.

3.1. Aim of the study The second part of this study was intended to test w hether Sea Cell® with different amount of the active silver fibre exert antibacterial. We were interested in testing the antibacterial activity against two different Staphylococcus aureus strains and one Escherichia coli strain. Staphylococcus aureus, is responsible for severe skin infection and the widespread of multiresistant strains is becoming a major problem not only in dermatology. Figure 8 shows a dermal infection with Staphylococcus aureus. Furthermore Staphylococcus aureus is a bacteria responsible for an aggravation factor in atopic dermatitis. Escherichia coli (E. coli) is a bacteria frequently encountered in interdigital and genital infections. In a second test series we could show activity of the silver-loaded SeaCell® fiber against the growth of the bacteria strains Staphylococcus aureus (Figure 9 and 10) and Escherichia coli (Figure 11). This antibacterial activity was dosed dependant with the highest activity in 100% Sea Cell® Active fiber independant of the production process and lowest in the Lyocell and SeaCell® fibers with 100% of the active silver load. An intermediate activity was detected in a mixed tissue with 5% of SeaCell® Active and more pronounced with 10% and 20% of the silver loaded fiber. Staphylococcus aureus is often responsible for outbreak and aggravation of atopic dermatitis. Escherichia coli is one of the most common bacteria in genital and anal region and responsible for infections in these areas.

Figure 9: Antibacterial activity against Staphylococcus aureus (strain ATCC 22923) of different fibres in a dose dependant manner at two different bacterial concentration in the inocculum. Highest antifungal activity was detected for SeaCell® Active 100% (SCA 100 nw=non woven)

Figure 10: Antibacterial activity against Staphylococcus aureus (strain ATCC 29213) of different fibres in a dose dependant manner at two different bacterial concentration in the inocculum. Highest antifungal activity was detected for SeaCell® Active 100% (SCA 100 nw=non woven)

Figure 11: Antibacterial activity against Escherichia coli (strain ATCC 35218) of different fibres in a dose dependant manner at two different bacterial concentration in the inocculum. Highest antifungal activity was detected for Sea Cell® Active 100% (SCA 100 nw=non woven)

4. CONCLUSION The present results demonstrate the antifungal and antibacterial effect of SeaCell® Active in a standardized in vitro test system. Thus this fiber seems to be suited for bio-active textiles in specific anatomical body regions and skin conditions with a susceptibility for fungal and bacterial infections namely with Candida species, Staphylococcus aureus and Escherichia coli. For example bed sheets and shirts for patients with atopic dermatitis, socks for persons with transpiration problems or long-term exposure to tightly closed shoes, underwear for diabetic patients and patients with obesity as well as sportswear, occupational textiles as well as home textiles e.g. for allergic patients and hygiene products. 5. ACKNOWLEDGEMENTS This study was sponsored by Alceru Schwarza, Rudolstadt, Germany 6. CORRESPONDENCE ADDRESS Joachim Fluhr, MD Dermatologist Head Skin Physiology Laboratory Dept. of Dermatology and Allergology Friedrich-Schiller-University Jena Erfurter Strasse 35 07740 Jena Germany fluhr@derma.uni-jena.de