ABSTRACT
Emergence of antibiotic resistant bacteria result in an approximately 550,000 deaths from bacterial infections annually.
Several studies reported interesting antibacterial and anti-biofilm activities of silver nanoparticles synthesized by
different physical, chemical and biological methods as an alternative to antibiotics. However, the resultant nanoparticles
were varying in size, shape, and had different antibacterial and antibiofilm activities with different concentrations.
Moreover, previous studies had investigated the antibacterial and antibiofilm activities in separate protocols and didn’t
investigate the real-time or dual effect of silver nanoparticles on both planktonic and sessile cells within single protocol.
This study aimed to synthesize silver nanoparticles through three methods and analyzing the simultaneous antibacterial
and antibiofilm activities against planktonic and sessile bacterial cells. Three methods were applied to analyze silver
nanoparticles and used to investigate the dual effect against bacterial biomass and biofilm formation. The results showed
that synthesized silver nanoparticles cause significant inhibition to bacterial cell biomass and bacterial biofilm formation
when compared with controls at low concentration. Significant Higher antibiofilm activity than antibacterial activity was
observed at very low concentration (0.0125 μg/ ml). The antibacterial and antibiofilm activity do not differ according to
the type of bacteria. Whereas, the antibacterial effect differs significantly according to the methods of silver nanoparticles
synthesis.
Keywords: Silver nanoparticles, Chemical synthesis, dual antibacterial and antibiofilm activities, gram positive and gram
negative bacteria.
