Zinc oxide nanoparticles have been coated onto paper, giving it an antibacterial surface suitable for use as wallpaper in hospitals.

Paper fibres (top) and coated with zinc oxide nanoparticles (bottom); insert showing nanoparticles

Researchers from the National Tsing Hua University in Taiwan led by Yong-Chien Ling found a way of coating paper with zinc oxide nanoparticles using ultrasound.

The nanoparticle-coated paper has antibacterial activity, tests against E. coli revealed. The paper could be used on hospital walls, in particular operating theatres, as well as residential complexes, said Ling. The coating approach could also be extended to textiles to generate suits with antibacterial properties to combat bioterrorism, he said.

Using ultrasound as a coating method is simpler than mechanical methods. It is also cheaper, uses less material, avoids waste and uses water as the solvent.

Ling believes there are many future applications of the coated paper, from security paper for optical communications to sensors. He also wants to develop the method to coat alumina and silica nanoparticles onto paper as an economical alternative for TLC plates for chromatography.

One challenge that Ling said remains is to study the long term stability of the coated paper and to overcome the possibility that photocatalytically reduced volatile organic compounds may produce stains on the antibacterial wallpaper.

Elinor Richards