Biomimetic synthesis of silver nanoparticles using microalgal secretory carbohydrates as a novel anticancer and antimicrobial

Secreted carbohydrates by Chlorella vulgaris cells were used for reducing and capping Silver nanoparticles (AgNPs). Oxygen-bearing functional groups on the carbohydrates found to be the main biochemical groups responsible for anchoring the metal nanoparticles. Transmission electron microscopy (TEM) micrographs showed that isotropic small particles with mean particles size of 7 nm were synthesized. Comparing the TEM results with DLS analysis revealed that the thickness of carbohydrate capping was about 2 nm. A zeta potential of +26 mV made the particles colloidally stable and desirable for anticancer and antimicrobial applications. The MIC against gram positive (Staphylococcus aureus) and gram negative bacteria (Escherichia coli) were determined to be 37.5 mu g ml(-1) and 9.4 mu g ml(-1), respectively. Treatment of Hep-G2 cells with 4.7 mu g ml(-1) AgNPs for 24 h reduced the cell viability to 61%. This concentration was also reduced the cell viability to 37% after 48 h of exposure.