Anticancer and antibacterial potential of methotrexate loaded iron nanoparticles produced by green synthesis method

An environmentally safe method � metal-vapor synthesis (MVS), was applied to produce iron nanoparticles (Fe NPs), which were conjugated with the drug methotrexate (MTX). The physicochemical properties and biological activity of the generated Fe NPs-MTX nanomaterials were analyzed. Transmission electron microscopy observations indicated that Fe NPs are stabilized in the form of aggregates with a size of 100 nm. The structure of these aggregates is similar to a �bunch of grapes�, which consists of metal particles about 1.83 nm in size. X-ray photoelectron spectroscopy evaluations showed that Fe both in the black and the composite with methotrexate was in Fe 3+ state, and the Fe 2+ state was also present in a small amount. Biological activity of Fe NPs-MTX conjugates against bacterial and human cells was assessed. Our results demonstrated inhibitory effects against both Gram-positive and Gram-negative bacteria that were superior compared to the activity of unloaded nanoparticles. Analyses with human cell lines showed time- and concentration-dependent cytotoxicity of Fe NPs-MTX against cancer cells and low inhibitory activity towards normal fibroblasts proving the anticancer potential of the nanoconjugates. In addition, colon adenocarcinoma-specific effect was observed based on the detection of highest inhibitory effects of Fe NPs-MTX against HT29 cell line. In vitro assays initially demonstrated lysosome-directed toxicity which after a longer exposition period (72-120h) was superseded by pronounced inhibition of cellular metabolic activity. These data indicate a wide biological functionality spectrum of MVS produced Fe NPs loaded with MTX and their potential for biomedical application.