## 3 Results and Discussion  
### SEM Analysis  
Scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) was employed to examine the surface morphology and elemental composition of electrospun PLA membranes with varied concentrations of MgO and AuNPs (Figures 3-12). The analysis focused on fiber diameter, nanoparticle distribution, and surface topography to evaluate how different modifications influence scaffold architecture and potential bioactivity in guided bone regeneration applications. The pristine PLA membrane (sample 1, Table 2) displayed smooth, bead-free nanofibers with a uniform diameter averaging 450 \(\pm\) 50 nm, reflecting an optimized electrospinning process. This morphology is typical of well-controlled PLA electrospinning, consistent with previous studies demonstrating smooth fiber surfaces with minimal topographical interference [15,16]. EDS spectra confirmed the exclusive presence of carbon and oxygen, validating the chemical purity of the unmodified PLA. This sample served as the control benchmark for assessing the morphological and compositional changes induced by nanoparticle incorporation. The introduction of a small amount of MgO (sample 2: 0.05 g) resulted in a slight increase in fiber diameter (\(\sim\)470 \(\pm\) 40 nm) and subtle surface roughening. EDS spectra showed detectable magnesium peaks, confirming MgO integration within the PLA matrix (Table 3). Increasing the MgO content further (sample 3: 0.25 g, Table 4) led to more pronounced surface texture, with bulging regions and a fiber diameter of \(\sim\)510 \(\pm\) 45 nm. These findings are in line with [PERSON] et al. [9], who reported that MgO enhances nanofiber surface area and roughness, promoting osteoblast activity. Figure 3: SEM microphotograph of sample 1 (pristine PLA) with EDS analysis. Figure 4: SEM microphotograph of sample 2 (5 g PLA; 0.05 g MgO) with EDS analysis. Figure 5: SEM microphotograph of sample 3 (5 g PLA; 0.25 g MgO) with EDS analysis. Figure 6: SEM microphotograph of sample 4 (5 g PLA; 0.25 g MgO) with EDS analysis. Figure 7: SEM microphotograph of sample 5 (5 g PLA; 0.5 mL nano Au) with EDS analysis. Figure 8: SEM microphotograph of sample 6 (5 g PLA; 1 mL nano Au) with EDS analysis. Figure 9: SEM microphotograph of sample 7 (5 g PLA; 2 mL nano Au) with EDS analysis. Figure 10: SEM microphotograph of sample 8 (5 g PLA; 0.05 g MgO; 0.5 mL nano Au) with EDS analysis. Figure 11: SEM microphotograph of sample 9 (5 g PLA; 0.25 g MgO; 1 mL nano Au) with EDS analysis. Sample 4 (0.5 g MgO) exhibited moderately coarse fibers (-530 \(\pm\) 50 nm), with visible crystallite exposure. Although slight micro-clustering was observed, EDS spectra showed intensified and well-dispersed Mg signals (Table 5). This supports previous observations by [PERSON] et al. [22] that higher MgO concentrations can promote both osteoinductivity and localized pH buffering due to nanoparticle crystallinity. \begin{table}
\begin{tabular}{c c c c c c} \hline
**Element** & **Atomic \%** & **Atomic \% Error** & **Weight \%** & **Weight \% Error** & **Net Counts** \\ \hline C & 42.9 & 0.2 & 36.1 & 0.2 & 117,741 \\ O & 57.1 & 0.4 & 63.9 & 0.4 & 72,433 \\ \hline \end{tabular}
\end{table} 
Table 2: Elemental composition of sample 1 (pristine PLA). Figure 12: SEM microphotograph of sample 10 (5 g PLA; 0.5 g MgO; 2 mL nano Au) with EDS analysis. Gold nanoparticle (AuNP) modification introduced different structural features. In sample 5 (0.5 mL AuNPs), the fiber diameter remained similar to that of the control (~460 \(\pm\) 40 nm), but localized granules became visible, likely representing superficial AuNPs (Table 6). Sample 6 (1 mL AuNPs) showed rougher surfaces (~470 \(\pm\) 35 nm) with dispersed AuNP aggregates, which is consistent with previous reports on AuNP clustering at moderate loading levels (Table 7) [10,11]. Sample 7 (2 mL AuNPs) demonstrated the most irregular topography and slight fiber thickening (~490 \(\pm\) 45 nm), accompanied by strong EDS gold signals and visible nanoparticle clusters.