The synthesized AgNPs colloidal solution had a localized peak at 405 nm indicating the presence of spherical structure. Moreover, this was also confirmed by the TEM micrographs.
The synthesized AgNPs without stabilizer had a short shelf life and agglomerated
quickly, linked to each other and created large particles.Lecithin molecules as a stabilizer separated the AgNPs and prevented their agglomeration.
The stabilized AgNPs only presented antibacterial properties in agar method due to their small size. The MBC/MIC ratio of stabilized AgNPs was low which indicated the capacity of bactericidal effects of these nanoparticles.
The sample with lower KLec/Ag did not show antibacterial properties at various concentrations of
silver in the well diffusion test because of less stability of colloidal silver nanoparticles. The bacteria reduction by AgNPs in the buffer solution was well described by the Chick-Watson model.
The specific coefficient of lethality was calculated from this model with a high
regression coefficient.
The specific coefficient of lethality was dependant on the lecithin concentration. An increase in lecithin concentration, as a phospholipids membrane stabilizer, caused slower release of silver and prolonged the time for total bacterial inactivation.