A N T I B A C T E R I A L F I B R E S

Josefin Illergård · Lars Wågberg · Monica EkAn eco-friendly antibacterial fibre-material has been developed. The material does not release toxic compounds and the method of fabrication is water-based, adding to the sustainability. This material is a potential competitor to conventional antibacterial fibre-based products, which commonly are leaching harmful compound such as silver or triclosan.

F O R A S U S T A I N A B L E F U T U R E

Comparing the antibacterial efficiency with the total charge of the substrate fibres and the subsequent polymer adsorption, the initial charge corre-sponded well with the resulting end-properties. The charge does thereby seem to be an important factor for the antibacterial properties. A further indication of this was that the efficiency was affected by the surrounding ionic strength.

By having an irreversible attached antibacterial substance on the material, an antibacterial surface is obtained where the bacteria are in-activated upon contact. The approach prevents the spreading of toxic compounds and do not promote antibiotic resistance.

When studying the bacteria on the material, the numbers were strikingly increased on the treated material and the bacteria were deformed. The positive charges do not only seem to attract and immobilise the bacte-ria, but also cause irreparable damage to the cells.

A problem with the contact-active materials have been the fabrication, as the existing protocols usually involves organic solvents and harsh conditions. We have developed an alternative method based on adsorption of cationic polyvinylamine (PVAm) in multilayers with polyacrylic acid, giving the material a positive charge. The process is water-based and carried out at room temperature, which gives both a sustainable use and fabrication process of the material. It is applicable of several types of materials, in-cluding wood-fibres, but the type of substrate may influence the properties.

The polymers are attached to the surface of the treated material in a water-based process. Bacteria are drawn to the surface by the positive charges and are inactivated upon the contact.

Potential product applications includes material for the health-care sector as well as in the hygienic sector and for water purification.

Several types of cellulosic fibres have been modified, including fluff fibres, TEMPO-oxidized fluff fibres, CTMP, dissolving-grade pulp and un-bleached kraft pulp. The treated fibres were shown to reduce bacteria with more than 99.9 % and suppress the bacterial growth in the presence of nutrients.

The developed eco-friendly antibacterial fibres show great potential for future fiber-based products, especially within health-care and in the hygienic sector. We now want to expand our research to study the macro-scale effects of having an eco-friendly antibacterial product.

KTH Royal Institute of TechnologyWood Chemistry and Pulp Technonogy

Stockholm, Sweden

Fluff

Dissolving

Kraft

CTMPTEMPO

A project financed by

The bacterial growth is inhibited by the use of fibres, as measured by optical density (turbidity) measurements after 24 hours. For TEMPO, no growth was detected even several days.

Comparision of nitrogen content in the samples, sorted after the initial total charge of the fibres.

0.00 0.05 0.10 0.15

TEMPO

CTMP

KRAFT

FLUFF

DISSOLVING

NO FIBRES

For more information, contact Josefin Illergård, PhD, at josefika@kth.se