Pathogen Reduction In Human Plasma Using Biosynthesized AgNPs With Juglans Regia Green Husk Aqueous Extract

To prepare human plasma for therapeutic purposes and serum with a low risk of contamination for cell culture use, a technique is needed to reduce blood borne pathogens. Silver nanoparticles (AgNPs) are a suitable option due to their low-risk of microbial resistance and strong antimicrobial activity.

As representative microorganisms, we tested Herpes simplex type 1 (HSV-1), Escherichia coli (ATCC 25922), and Staphylococcus aureus (ATCC 1413). The cytotoxicity of biosynthesized AgNPs was assessed on the Vero cell line. The Maximum Non-Toxic Dose (MNTD) of AgNPs did not affect the virus. In order to address the high toxicity of AgNPs and utilize the highest colloidal concentration of AgNPs (300 µg/ml) that did not precipitate within the 24-hour examination period, we developed a removal process. AgNPs were removed after being exposed to viruses and bacteria. This removal step was done by addition of magnetic iron oxide nanoparticles (iron oxide NPs). Then, treated virus and bacteria were exposed to neodymium magnet, and were used for cell inoculation.

Both AgNPs and iron oxide NPs reduced the titer of virus by at least 3.5 log when used together. Additionally, they inactivated 106 CFU/ml of bacteria in human plasma. While each nanoparticle exhibited antiviral activity individually, but also their effect was enhanced when used simultaneously.

Human plasma pathogens were reduced using AgNPs and/or iron oxide NPs. The plasma could be treated with these nanoparticles, and subsequently the magnetic nanoparticles that adsorbed silver nanoparticles were separated from the plasma using a neodymium magnet, as one of the techniques for pathogen reduction.