Gold Nanoparticles Decorated Chitosan-Agarose Modified Magnetic Nanocomposite: Catalytic Application for the Preparation of Tetrazoles and Biological Evaluation for the Treatment of Lung Carcinoma

This article describes a new type of core–shell pattern Fe₃O₄ nanoparticle (Au/CS-agar@Fe₃O₄) that was developed using Au NPs and chitosan-agarose composite. Our goal in catalytic exploration was to synthesize 5-substituted-1H-tetrazoles via click synthesis using aryl halides. By this method, using K₄[Fe(CN)₆] as a nontoxic CN resource, we treated a variety of aryl halides (Cl, Br, and I) using the highly effective and reusable Au/CS-agar@Fe₃O₄ catalyst, catalyzing the [3 + 2]-cycloaddition of the corresponding aryl nitriles with NaN₃ to the successive one-pot solvent-free preparation at 120 °C of 5-substituted-1H-tetrazoles. The various substrates provided a yield in the range of 70–96% after the reaction of 12 h. The catalyst's robustness was supported by tests for leaching, hot filtration, and catalyst reusability nine times in a row. In the medicinal part, the anticancer properties of Au/CS-agar@Fe₃O₄ nanocomposite against lung cancer cell lines were determined. In vitro experiments, after 3–4 passages, the cancer cells (NCI-H1563, NCI-H1573, NCI-H1975, and NCI-H661) and normal cell (HUVEC) were prepared in terms of morphology and number. After segregating the cells from the flask surface by trypsin–EDTA, cell viability was assessed and counted, and 3 × 10³ cells were cultured with or without nanoparticles in 96 wells. IC₅₀ of Au/CS-agar@Fe₃O₄ nanocomposite was 160, 173, 142, and 212 on NCI-H1563, NCI-H1573, NCI-H1975, and NCI-H661 cancer cells. In this study, the highest antioxidant efficacy on DPPH was reported approximately 100% at 1000 μg/ml. The antioxidant IC₅₀ of Au/CS-agar@Fe₃O₄ nanocomposite was 254 µg/mL.