| dc.description.abstract | Green synthesized silver nanoparticles have gathered huge attention from scientists thanks
to their safe yet high efficiency in biological activities. Fungal melanins are non-toxic
agents and have been proven to have the capability of mediating the generation of silver
nanoparticles. In this study, for the economic approach, melanin-containing solution and
crude melanin extracted from fruiting bodies of Xylaria sp. were evaluated for the direct
synthesis of silver nanoparticles from silver nitrate (AgNO3). Then antibacterial activities
of the obtained nanosilver particles were evaluated.
The optimized conditions for synthesizing silver nanoparticles using melanin-containing
solution were found as melanin solution mixed with 0.1 M silver nitrate (2:1, v/v) and
incubated for 3 hours. UV-Vis and FTIR spectra successfully determined the characteristic
peaks as well as the involvements of functional groups in the synthesized nanoparticles.
In addition, SEM and XRD indicated the products were spherical and in nano-dimension.
There was a slight difference in the size of the nanoparticles produced from the treatment
utilized melanin-containing solution and the treatment utilized crude melanin, of which
the size was 24.60 ± 4.05 nm and 18.85 ± 3.75 nm, respectively. Both samples displayed
peaks at (111), (200), (220) and (311) orientations indexed to the face-centered cubic (fcc)
structure. However, based on the size difference, they were still considered as two
different nano-samples in this study.
The two nano-samples were tested against acne-causing bacteria including
Stapphylococcus aureus and Cutibacterium acnes using well agar diffusion test method
and microdilution method, then the minimum inhibitory concentration (MIC) values were
calculated. Among the two samples, the silver nanoparticles from the crude melanin were
found to be remarkably potent: 90% of S. aureus and C. acnes populations were inhibited
at the concentration of 62.5 (ug/mL) and 15.625 (ug/mL), respectively. These activities
are significantly higher than those of the positive control (Erythromycin) that inhibited
90% of the bacterial growth at up to 4000 (ug/mL).
This project has illustrated the feasibility of using different forms of melanin for the direct
synthesis of silver nanoparticles. The obtained findings suggested the potential of such
nanoparticles in acne treatment and further studies are worth carrying out. | en_US |
