The Hohenstein Institute has a new, proven test system for textile manufacturers to gauge the effect of antibacterial finishes on skin flora.
Antibacterial textiles (products treated with silver) have an odor-eliminating functionality and so are popular for first layer or sports clothing worn directly against the skin. In recent years, however, antimicrobial textiles faced criticism in the media, creating unease among customers.
A recent test of cycling trousers carried out by the German consumer advice magazine Öko-Test also gave lower ratings to textiles containing silver. Critics suggest that the antimicrobial effect could impact healthy human skin flora if it is too ‘strong.’ This supposedly becomes a problem, especially when antibacterial fibers are used in clothing that is worn close to the skin, such as underwear or socks.
There is one aspect that is usually overlooked in this criticism, though: the effective bioavailability of the active silver substances in the product. Researchers from the Hohenstein Institute in Bönnigheim, Germany, have already refuted the fears about commercial-quality antibacterial products in an extensive scientific field study conducted several years ago (AiF no. 15537 N). A comparison between the influence of normal and antibacterial functionalized chemical fibers on the skin flora and the micro climate showed no significant differences. The research results prove that antibacterial agents in high-quality textile finishes are incorporated into the product to work in the microscopic range on the surface of the fiber, preventing the formation of odor on the product. Most of the silver ions in garments worn against the skin are simply not bioavailable and therefore cannot have any effect there.
They can also not be increasingly released through sweating or washing. The researchers were able to give the basic all-clear for the products examined. However, they also suggested studying the effects of these textiles on the skin flora in the context of consumer protection.
Not all products can be examined in field studies over weeks or months before introduction to the market and there was no quick test available so far. The Hohenstein researchers have now tackled this problem. A new test system allows textile manufacturers to have the effects of antibacterial finishes on the skin flora examined during product development. The practicability and reliability of the results produced by the test system have already been proven through examination and comparison of functional textiles with an antibacterial finish.
The test is based on a standardized model of human skin flora, which simulates the germ population, topography and environmental properties of healthy skin. To achieve this, several germ types were selected from the micro flora of a human epidermis and applied to a specially developed artificial skin replacement material (HUM-skin). The effect of the test material on these germs is quantified during a wearing simulation over a period of 18 hours and then evaluated against a control material without antimicrobial finish. This process examines the change in the total number of germs as well as the number of individual germs. If no significant reduction in the number of germs occurs within the exposure time, the textile is considered to be safe with regard to the body’s own skin flora.
The test results can be advertised using the Hohenstein Quality Label ‘Antibacterial & Skin flora neutral’. Successful testing for antibacterial effectiveness according to DIN EN ISO 20743 is a prerequisite for obtaining the label.