Comparative studies of three novel freshwater microalgae strains for synthesis of silver nanoparticles: insights of characterization, antibacterial, cytotoxicity and antiviral activities

The therapeutic efficacy of universal drug-delivery systems depends on their capability to escape the immune system by overcoming the biological barriers of the body and concentrate at target tissues to eradicate only diseased cells. Biologically synthesized nanoparticle systems possess almost all of these qualities and utilize their targeting ability through cellular membrane interactions and making the targeting system biocompatible. In the present study, microalgae-mediated silver nanoparticles (AgNPs) targeted bacterial, fungal, cancerous and viral infected cells without harming normal cells. These AgNPs provide a comparative study on broader range of size and shape, synthesized by ethanolic extract of three different freshwater microalgae species, Dictyosphaerium sp. strain HM1 (DHM1), Dictyosphaerium sp. strain HM2 (DHM2) and Pectinodesmus sp. strain HM3 (PHM3). Characterization of AgNPs was done by XRD, SEM, TEM, EDS, FTIR and UV-Vis spectrophotometry. Significant activity against 14 bacterial strains, the fungal strain Candida albicans, hepatocellular carcinoma (HepG2) and breast cancer (MCF7) cell lines, and Newcastle Disease Virus (NDV) on Huh7-infected cells suggest the potential use of microalgae extract prepared nanoparticles in biomedicine, pharmaceutics and drug delivery.