Contact-Active antibacterial fibres by the Layer-by-Layer approach

Traditional antibacterial materials is based on the leaching of antibacterial agents, for example, silver or triclosan. However, this approach is unwanted as the substance eventually ends up in nature, disturbing natural biological processes. In addition, giving the wrong dosage or wrongly chosen biocide, the bacteria can become resistant, making the bacteria a hazardous health risk. But there are other alternatives.

My project focuses on surface modification of cellulose fibre by using strong positive charged polyelectrolyte to achieve the antibacterial properties. The renewable cellulose fibre is used as substrate as it is widely utilized in tissues and hygiene products, which are products that can have added value by having an antibacterial modification. The layer-by-layer (LbL) technique makes it possible to get an antibacterial function using mild react conditions and water-based solutions. In this technique, charged polymers are physically adsorbed onto surfaces. By having the antibacterial polymer attached to the surface we achieve a so-called contact-active, or non-leaching, antibacterial material. We thereby avoid the problems of leaching toxic substances into the environment. Currently we use the highly charged cationic polymer polyvinylamine (PVAm) to make our contact-active antibacterial fibres, but a future possibility is to use bio-based polymers. An example of such polymers is chitosan and quaternized chitosan that possesses high positive charges.[JI1] Chitin, a polymeric compound obtained by extraction from the shell of shrimps and crabs, has been found to both be biocompatible and have good antibacterial property. Its derivative, the quaternized chitosan, is considered as a better antibacterial agent for the fibre surface modification as it has better solubility in water[JI2] . Something that could be also potentially interesting for me is to use wood-based polymers from biorefinery concept. It’s fascinating to make an antibacterial material that entirely made of wood!

PhD student: Chao Chen