This new group of glass materials with biocide activity eliminates over 99.9% of pathogenic microorganisms, but has no toxic effects on the environment and on eukaryotic organisms (like animals and humans). This development could enable interesting applications for biomedical uses, water treatment and food packaging.
Transition electron micrographs of the glass powders.Zinc oxide has a high biocide activity. Nevertheless, it is an unstable compound and consequently it has not been possible to incorporate it into materials like glass until now, and all previous attempts have failed. There is no experimental evidence of any stable glass with more than 10% of zinc oxide.

Now, scientists at the Materials Science Institute of Madrid (ICMM), of the CSIC, have obtained glass with zinc oxide up to 40%. They have demonstrated that this glass is stable and maintain the biocide properties.

"The biocide activity of this glass is effective against Gram bacteria (Eschericia coli), Gram + (Staphylococcus aureus) and yeast (Candida krusei). It can work as a ‘dispensers’ of zinc ions  in different environments – such as distilled water or non-treated water-  and can be obtained by conventional methods of production, at low cost. This gives an answer to one of the most urgent issues nowadays: avoiding diseases and bio-contamination caused by microorganisms”, explains José Serafín Moya, a CSIC scientist at the Materials Science Institute of Madrid (ICMM).

"It gives an answer to one of the most urgent issues nowadays: avoiding diseases and bio-contamination caused by microorganisms"

What has made the development of the new glass possible was to find out the appropriate position in the glass structure of the zinc oxide in order to make it stable. “We have even discovered that zinc oxide in concentrations higher than 20% can be part of the rigid network structure of the glass, something we did not know until now”, adds this scientist. The resultis a  glass that can constantly release (lixiviate) zinc ions for a long time, in a controlled way.

This development enables the dosage of the zinc ions released, therefore adapting the glass for every application.
Among the possible uses, there are medical implants and surgical tools, as well as equipment and clothes for hospitals, water treatment and food packaging. “This is the first step to obtain new biocide materials based on this glass, such as glass nanofibers, coatings for dental implants or surgical prostheses”, ends Moya.

L. Esteban-Tejeda, C. Prado, B. Cabal, J. Sanz, R. Torrecillas, J. S. Moya. Antibacterial and Antifungal Activity of ZnO Containing Glasses. PLOS ONE. DOI: 10.1371/journal.pone.0132709