Silver is considered as antibacterial agent with well-known mode of action and bacterial resistance against it is well described. The development of nanotechnology provided different methods for the modification of the chemical and physical structure of silver, which may increase its antibacterial potential. The physico-chemical properties of silver nanoparticles and their interaction with living cells differs substantially from those of silver ions. Moreover, the variety of the forms and characteristics of various silver nanoparticles are also responsible for differences in their antibacterial mode of action and probably bacterial mechanism of resistance. The paper discusses in details the aforementioned aspects of silver activity.

Different sol–gel strategies based on the Stöber method are proposed enabling preparation of nanoparticles of SiO₂–CaO bioactive glass with different size, narrow size distribution and good dispersion capability. Eu³⁺-doped glass nanoparticles with luminescent properties can also be obtained.