Abstract
Background and Objective: The synthesis of nanomaterials play significant role in nanotechnology. The pathogenic organisms are more resistant to the available antibiotics. The green synthesis of silver nanoparticles by using marine algae, which have a wide range of bioactive secondary metabolites is a need to find new antibiotics. Materials and Methods: The red alga, Laurencia papillosa was extracted with deionized water. The algal extract was added to 1.0 mM AgNO3 solution. The aqueous solution was subjected to stirring for overnight. The reaction mixture was monitored to emphasize the formation of silver nanoparticles. The change in color of the solution was recorded by using UV-vis spectrophotometer. The biosynthesized nanoparticle solution was subjected to Fourier transform infrared and x-ray diffraction analysis. The morphology of the nanoparticles was observed by using scanning electron microscope. The antibacterial and antifungal activity of algal silver nanoparticles was tested by using agar well-diffusion method. The minimum inhibitory concentration of the solution was studied. Results: The UV-vis spectroscopic analysis confirmed the silver nanoparticle formation with the peak at 450 nm after 72 h. Fourier transform infrared measurement was carried out to identify the possible biomolecules responsible for the stabilization of the newly synthesized silver nanoparticles. The x-ray diffraction analysis showed that the silver nanoparticles synthesized from the algal extract were highly crystallized and purified. The scanning electron microscope image showed the predominant of cubic shape nanoparticles on the surface of the cell. The antimicrobial activity of synthesized silver nanoparticles (50-150 mu L) was evaluated against pathogenic bacteria and fungi. The greatest antibacterial and antifungal activities were observed against Bacillus subtilis and Aspergillus flavus, respectively. The minimum inhibitory concentration for nanoparticles was ranged between 10 and 20 mu g mL(-1). Conclusion: The results confirmed that the capping of algal extract with silver nanoparticles is capable of rendering antimicrobial efficacy and hence has a great potential in the preparation of therapeutic drugs.