Hybrid AgNPs/eggshell calcium carbonate particles and their antimicrobial efficiency

In this study, hybrid particles of AgNPs-loaded eggshell calcium carbonate
(AgNPs/eCaCO3) were prepared in situ by precipitating the eggshell in the
presence of freshly prepared AgNPs with a particle size of 10-30 nm. The
hybrid particles were comparatively precipitated in situ at 25 °C and 35
°C using poly (sodium 4-styrenesulphonate) as a polyelectrolyte. The
AgNPs/eCaCO3 particles prepared at 25 °C had a spherical morphology with a
mean diameter of 3.56 mm, and BET surface area of 85.08 m2/g. On the other
hand, the particles prepared at 35 °C had a broader size distribution with
a mean diameter of 3.19 mm, and a BET surface area of 79.25 m2/g.
AgNPs-loaded commercial calcium carbonate particles (AgNPs/e=CaCO3)
comparatively prepared at 35 °C were perfectly spherical with a mean
diameter of 5.61 mm. At preparing temperature of 25 °C, the hybrid
particles contain AgNPs of 0.78 wt% for AgNPs/eCaCO3 and 3.20 wt% for
AgNPs/CaCO3. The AgNPs/eCaCO3 and AgNPs/CaCO3 particles exhibited the same
efficiency against bacteria extracted from beef with an average inhibition
zone diameter of 7–10 mm according to the modified Kirby–Bauer disc
diffusion assay depending on their concentration and beef source. Freshly
prepared silver colloids showed comparatively poorer antimicrobial
efficiency with an inhibition zone diameter around 7 mm.