## 3 Results and Discussion
### Anti-Biofilm Activity  
Although the anti-biofilm activity of AgNPs synthesized by various plant extracts has been well documented in the literature, reports on the anti-biofilm potential of nanoparticles synthesized by date seed extract are scanty. The anti-biofilm potential of Aw\(-\)AgNPs against various bacterial strains is shown in Figures 6 and 7. It has been observed that Aw\(-\)AgNPs inhibits the biofilm formation of _E. coli_ and _S. aureus_ by 54.97% and 51.62%, respectively, at a 25 \(\upmu\)g/mL concentration. Conversely, the same concentration of Aw\(-\)AgNPs showed lower activity against the biofilm of _Pseudomonas aeruginosa_, _Enterococcus faecalis_, and _Klebsiella pneumoniae_. The findings from this study suggest that Aw\(-\)AgNPs could reduce the biofilm formed by Gram-negative as well as Gram-positive bacteria (Figure 7). It was also observed that a 50 \(\upmu\)g/mL concentration of Aw\(-\)AgNPs significantly inhibited the biofilm formation in E. coli and S. aureus, while a 100 \(\upmu\)g/mL concentration of Aw\(-\)AgNPs is able to inhibit the biofilm formation in the rest of the bacterial strains. Previous studies also suggested the same pattern of anti-biofilm activity in AgNPs [7]. [PERSON] et al. [32] reported the inhibition of the biofilm activity of the Ajwa dates of 70.5% and 54.19% against S. aureus and Salmonella strains. In our study, we reported significant 70, 66, 39, 43, 41% inhibition against _E. coli_, _S. aureus_, _P. aeruginosa_, _Enterococcus faecalis_, and _Klebsiella pneumoniae_. Furthermore, Aw\(-\)AgNPs at a dose of 50 \(\upmu\)g/mL prevented 30 to 60% of the biofilm formation and diminished the growth of the bacteria itself. [PERSON] et al. also reported similar results against biofilm-producing Gram-positive and Gram-negative bacteria and observed that 100 \(\upmu\)M of AgNPs resulted in a 40 to 70% reduction in biofilm [33].  
Figure 5: Assessment of anti-bacterial activity of Aw\(-\)AgNPs (100 \(\upmu\)g/mL) and positive control, penicillin. Values expressed as mean \(\pm\) SE of the mean (\(n=3\)). * Denotes significant difference of positive control (penicillin) with test samples at \(p<0.05\) and **\(p<0.01\).  
Figure 6: Anti-biofilm activity, represented by biofilm inhibition (%), of silver nanoparticles (ug/mL) synthesized from Ajwa dates extract against different standard bacterial strains. Significant difference (\(p<0.05\)) was observed by one-way ANOVA test.  
Figure 7: Image showing the screening of biofilm inhibition in the presence of Aw–AgNPs. **Rows (A,B)**, **negative control (NC)**: culture media only, no bacterial colony, and no Aw–AgNPs; **Row (C,D)**, **positive control (PC)**: culture media plus 5 different bacterial colonies placed accordingly in different wells and no Aw–AgNPs; **Row (E–H)**: culture media plus 5 different bacterial colonies placed accordingly in different wells, as well as various concentrations (100 to 12.5 \(\upmu\)g/mL) of AgNPs synthesized from Ajwa date extract. EC = indicates _Escherichia coli_; SA indicates _Staphylococcus aureus_; PA indicates _Pseudomonas aeruginosa_; EF indicates _Enterococcus faecalis_; KP indicates _Klebsiella pneumoniae_.