Chitosan-Coated Gold Nanoparticles Induce Low Cytotoxicity and Low ROS Production in Primary Leucocytes, Independent of Their Proliferative Status

(1) Background: Chitosan-coated gold nanoparticles (CH-AuNPs) have important theranostic applications in biomedical sciences, including cancer research. However, although cell cytotoxicity has been studied in cancerous cells, little is known about their effect in proliferating primary leukocytes. Here, we assessed the effect of CH-AuNPs and the implication of ROS on non-cancerous endothelial and fibroblast cell lines and in proliferative lymphoid cells. (2) Methods: The Turkevich method was used to synthetize gold nanoparticles. We tested cell viability, cell death, ROS production, and cell cycle in primary lymphoid cells, compared with non-cancer and cancer cell lines. Concanavalin A (ConA) or lipopolysaccharide (LPS) were used to induce proliferation on lymphoid cells. (3) Results: CH-AuNPs presented high cytotoxicity and ROS production against cancer cells compared to non-cancer cells; they also induced a different pattern of ROS production in peripheral blood mononuclear cells (PBMCs). No significant cell-death difference was found in PBMCs, splenic mononuclear cells, and bone marrow cells (BMC) with or without a proliferative stimuli. (4) Conclusions: Taken together, our results highlight the selectivity of CH-AuNPs to cancer cells, discarding a consistent cytotoxicity upon proliferative cells including endothelial, fibroblast, and lymphoid cells, and suggest their application in cancer treatment without affecting immune cells.