Phyco-linked vs chemogenic magnetite nanoparticles: Route selectivity in nano-synthesis, antibacterial and acute zooplanktonic responses.

Despite the fact that magnetic iron oxide nanoparticles (FeO-MNPs) considered as the most promising nanoparticles (NPs) in biomedicine and environmental biotechnology, their safety and ecotoxicological impacts of biogenic and chemogenic routes of FeO-MNPs in the marine aquatic system is scarcely studied. In this work, we report the optimized and suitable phyco-synthesis route for nano-FeO based on the six selected species of the Persian Gulf seaweeds: Ulva prolifera, U. flexuosa, U. linza, U. intestinalis, U. clathrata, and Sargassum boveanum. Moreover, antibacterial activities and acute zooplanktonic responses in Artemia salina and acorn barnacle Amphibalanus amphitrite to chemogenic and biogenic FeO-MNPs, were evaluated. Although all the seaweeds extract showed reducing potential for FeO-MNPs green synthesis - mainly on the basis of characterization results- the algal route selectivity has been demonstrated to be important for the biosynthesis of magnetite NPs. Herein, the cubo-spherical and polydisperse U. prolifera-derived FeO-MNPs with particles sizes of 9.59 nm were the best ones. The comparative zooplanktonic cytotoxicity of chemo- and bio-route of FeO-MNPs exhibited no acute toxicity in nauplii and adults of A. salina (96-h EC ≥ 1000 mg/L) and the potential of toxicity in A. amphitrite nauplii (48-h EC = 466.5 and 842.3 mg/L for chemo- and bio-route of FeO-MNPs, respectively). The in vitro antimicrobial activity of both chemo- and bio-route of magnetite NPs to selective human pathogenic bacteria and fungi (i.e. n = 11) showed strong antagonistic activity against Staphylococcus epidermidis, Bacillus subtilis, B. pumulis, and Saccharomyces cerevisiae. In conclusion, these findings demonstrate the optimized phyco-fabrication of FeO-MNPs as promising nontoxic approach in ecobiotechnology, the new insight about the potential adverse effects of chemosynthesized FeO-MNPs to crustacean zoo-organisms after their possible entrance into the marine environments, and bio/chemo-route FeO-MNPs as pivotal agent for nanoantimicrobials.