A Nanocomposite Endows Antimicrobial Properties to Diverse Materials

The agglomerated SiO2 matrix forms a particle with a typical size of 0.1 to 1 ìm; each silica particle contains many smaller silver metal particles each with a typical size between 5 and 20 nanometers. These silver particles are found on the surface of the silica and also embedded throughout the silica structure. The silver nanoparticles act as a reservoir for release of silver ions (Ag+) that are the active agent against bacteria.

The presence of both surface and embedded silver particles gives the material a combination of immediate antimicrobial activity combined with long-term durability that the fine size of the silica particles allows them. The antimicrobial effect of the silver can provide beneficial functionality in a broad range of applications, including synthetic fibers, textile finishing, plastic parts and moldings, paints and coatings, medical applications, and cosmetics. The The HeiQ-Silver powder is manufactured by HeiQ Materials (Bad Zurzach, Switzerland).

While metallic silver is historically recognized as being antimicrobial, it is not the pure silver that is active, but the liberated silver ions. The effect of silver ions stems from three key mechanisms: The binding and damage to the bacterial cell surface; inhibition of respiration by suppressing transport of vital Ca2+ and Zn2+ ions across the cell membrane; and binding strongly to electron donor groups on constituent bacterial molecules containing sulfur, oxygen, or nitrogen.


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