Hohenstein declares antibacterial clothing to be safe
The Hohenstein Institute, Germany, has carried out the first scientific study into the use of antibacterial chemical fibres in clothing and the possible negative effects on skin flora and the skin’s microclimate, and has found that antibacterial clothing is in fact safe.
In a research project that has now been completed, financed by the Federal Ministry of Economics and Technology (BMWi) via the Federation of Industrial Research Associations AIF, Hohenstein researchers were able to investigate this subject in a large-scale field study.
“Most of the antimicrobial garments on the market at present contain silver. Even though silver has a very good image and has been used for decades with no problem in other areas such as for treating drinking water, purchasers of antibacterial clothing have been confused by, in some cases, highly controversial debate and reporting in the media,” said a press release issued by the institute.
A total of 60 healthy volunteers took part in the Hohenstein's trial for a period of six weeks. Special t-shirts were made for the survey, with an antibacterial treatment on one side (verum), while the other half served as a non-antibacterial placebo. For comparison purposes, researchers studied the effect of both an antibacterial spinning additive (polyester fibres containing silver) and an antibacterial finishing treatment containing silver. Before the survey, the antibacterial activity in the samples was tested in the laboratory using test bacteria such as Staphylococcus aureus and Klebsiella pneumonia. Then the t-shirts had to be worn by the volunteers every day for at least eight hours for a period of four weeks. Various parameters for the skin flora and microclimate were investigated each week. For the entire period of the trial, the health of the volunteers in this placebo-controlled, intra-individual survey was monitored by a dermatologist and the test sites on the skin were dermatologically assessed.
At the beginning of the trial and during and after the series of tests, researchers identified the types of skin bacteria that were typical of each of the volunteers' natural skin flora. At no time did any pathogenic bacteria occur. The individual differences between the volunteers were all within a normal range when compared with data on skin flora in the literature. No effect by the textile fibres on the skin flora could be detected either in individual volunteers or when the whole group or parts of it were considered.
The results of the study confirm that healthy human skin flora are very stable. Most notably, there was no significant difference in the total number of bacteria between the functionalised side (verum) and the control side (placebo). Nor was there any variation in the individual range of bacteria specific to each volunteer which could be attributed to the functionalised textile fibres.
In addition to the skin flora, researchers also looked at the skin microclimate. They studied three aspects of the microclimate relating to skin physiology: the vapour loss through the skin (trans-epidermal water loss or TEWL, as a direct measure of the barrier effect of the skin), skin moisture levels and the pH value. No significant effect on vapour loss from the skin could be detected on either the functionalised (verum) side or the control side (placebo).
The results indicate that the antibacterial fibres had no effect on the skin barrier. There was equally little change in the pH value of the volunteers' skin or in the moisture levels in their skin. None of the trial participants showed any dermatological changes such as increased dryness or inflammation.
Antibacterial textiles can therefore be classified as safe, according to the Hohenstein Institute, which intends to submit its data for publication in an international specialist dermatology journal.
