## 3 Results and Discussion
### High-Resolution Transmission Electron Microscopy of Synthesized AgNPs  
Structural characteristics of the synthesized AgNPs were examined using HRTEM. NPs were evenly dispersed and occasionally detected either in clusters or merging into nano-clusters. The slight aggregation could be attributed to the elevated surface energy typically encountered during the preparation of NPs in an aqueous medium [81]. NPs synthesized from extracts of both leaf and stem (Figure 6) exhibited a small, generally spherical shape. Some NPs displayed either a spherical or triangular morphology. This variability in shape could be linked to distinct sets of phytochemicals that facilitate the reduction and stabilization of the AgNPs [82]. The kinetic energy of molecules increases at higher temperatures. This reaction speeds up the Ag ion consumption, thus reducing \begin{table}
\begin{tabular}{c c} \hline \hline
**Type of Extract** & **Average \% Weight** \\ \hline Methanol leaf & 16.87 \(\pm\) 0.89 \\ Methanol stem & 14.78 \(\pm\) 3.53 \\ Fresh leaf & 9.47 \(\pm\) 1.38 \\ Fresh stem & 8.12 \(\pm\) 0.71 \\ Powdered leaf & 8.85 \(\pm\) 1.09 \\ Powdered stem & 7.13 \(\pm\) 1.44 \\ \hline \end{tabular} Data displayed as mean \(\pm\) SD of triplicate.  
\end{table} 
Table 2: Average % weight of AgNPs synthesized from various leaf and stem extracts of _B. albostellata_. Figure 5: Micrographs of AgNPs synthesized from the powder leaf extracts (**A**,**B**) and powder stem extracts (**C**,**D**) of _B. albostellata_. (**A**,**C**) Aggregated AgNPs; (**B**,**D**) EDX spectroscopy. Circles indicate AgNP agglomeration. the likelihood for particle size development [83]. This could explain the small particle size found in the HRTEM micrographs. [PERSON] and [PERSON] [83] have proposed that the size of AgNPs can be modified by manipulating pH levels, concentration, and temperature. A thin film layer was observed surrounding the AgNPs in both leaf and stem extracts (Figure 6B,D). [PERSON] et al. [84] have detected similar films around synthesized AgNPs and recognized this as AgNPs capping the functional groups. [PERSON] et al. [61], have validated this observation by identifying comparable films in the aqueous leaf extracts of _B. longiflora_, proposing that the AgNPs are not able to form a single gel. Figure 6: HRTEM micrographs of the AgNPs synthesized from (**A**,**B**) methanolic leaf extracts; (**C**,**D**) methanolic stem extracts, (**E**,**F**) fresh leaf extracts; (**G**,**H**) fresh stem extracts, and (**I**,**J**) powdered leaf extracts; (**K**,**L**) powdered stem extracts of _B. albostellata_. Arrowhead indicates film around AgNPs. the thin layer constituted the organic material capping the AgNPs. Furthermore, [PERSON] et al. and [PERSON] [85; 86] have suggested that the functional group's capping might enhance the stability of AgNPs in the solution. According to the histogram for mean particle size, AgNP sizes were not uniform and varied across the different extracts (methanolic leaves and stems (Figure 7A,B)), (aqueous fresh leaves and stems (Figure 7C,D)), (and aqueous powdered leaves and stems (Figure 7E,F)) from _B. albostellata_, However, all particles were below 100 nm. The sizes of synthesized NPs from the leaf and stem extracts were as follows: 31.69 nm (Figure 6A), 34.32 nm (Figure 6B), 21.77 nm (Figure 6C), 20.48 nm (Figure 6D), 18.39 nm (Figure 6E), and 16.57 nm (Figure 6F), respectively. AgNPs of a similar size (15-30 nm) have been observed in _B. cristata_[75]. Additionally, spherical NPs synthesized from the aqueous leaf extracts of _B. prionitis_ varied from 10 to 20 nm [10]. Figure 7: The mean particle size of synthesized AgNPs. (**A**) methanolic leaf extracts; (**B**) methanolic stem extracts; (**C**) aqueous fresh leaf extracts; (**D**) aqueous fresh stem extracts; (**E**) powdered leaf extracts; (**F**) powdered stem extracts of _B. albostellata_. The mean particle size in Figure 7A is right skewed; this means that the size of the majority of the AgNPs from the methanolic leaf extracts were between 20-40 nm.