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Although iron is essential for all forms of life, it is also potentially toxic to cells as the increased and unregulated iron uptake can catalyze the Fenton reaction to produce reactive oxygen species (ROS), leading to lipid peroxidation of membranes, oxidation of proteins, cleavage of DNA and even activation of apoptotic cell death pathways. We demonstrate that Fe(hinok) 3 (hinok = 2-hydroxy-4-isopropyl-2,4,6-cycloheptatrien-1-one), a neutral Fe(III) complex with high lipophilicity is capable of bypassing the regulation of iron trafficking to disrupt cellular iron homeostasis; thus, harnessing remarkable anticancer activity against a panel of five different cell lines, including Pt-sensitive ovarian cancer cells (A2780; IC 50 = 2.05 ± 0.90 μM or 1.20 μg/mL), Pt-resistant ovarian cancer cells (A2780cis; IC 50 = 0.92 ± 0.73 μM or 0.50 μg/mL), ovarian cancer cells (SKOV-3; IC 50 = 1.23 ± 0.01 μM or 0.67 μg/mL), breast cancer cells (MDA-MB-231; IC 50 = 3.83 ± 0.12 μM or 2.0 μg/mL) and lung cancer cells (A549; IC 50 = 1.50 ± 0.32 μM or 0.82 μg/mL). Of great significance is that Fe(hinok) 3 exhibits unusual selectivity toward the normal HEK293 cells and the ability to overcome the Pt resistance in the Pt-resistant mutant ovarian cancer cells of A2780cis.

Although a biologically nonessential element in living organisms, aluminum is notably nontoxic to eukaryotic cells and has a venerable history of medicinal use. We demonstrate that polyethylene glycol-coated γ-alumina nanoparticles (Al 2 O 3 -NPs) with an average size of 15 nm prepared from a commercial bulk γ-alumina (γ-Al 2 O 3 ) via the top-down sonication technique exhibit antibacterial activity that is comparable to that of AgNPs against both the Gram-negative drug-susceptible Pseudomonas aeruginosa (DSPA) and multidrug-resistant Pseudomonas aeruginosa (DRPA) bacteria, while the antibacterial activity of such Al 2 O 3 -NPs considerably surpasses that of AgNPs against both the Gram-positive methicillin-susceptible Staphylococcus aureus (DSSA) and methicillin-resistant Staphylococcus aureus (MRSA) bacteria. We also demonstrate that the DSPA bacteria sequentially exposed to Al 2 O 3 -NPs for 30 days show no indication of resistance development. Furthermore, such Al 2 O 3 -NPs can completely overcome the drug resistance developed in the conventional antibiotic ciprofloxacin-resistant and AgNP-resistant mutants without developing Al resistance.

The lack of acid stability in the stomach and of temporal stability when moving through the gastrointestinal (GI) tract has made the development of oral magnetic resonance imaging (MRI) contrast agents based on the platform of Gd 3+ -complexes problematic.On the other hand, the negative contrast enhancement produced by the T 2 -weighted magnetic metal oxide nanoparticles (NPs) often renders the image readout difficult. Biocompatible NPs of the manganese Prussian blue analog K 2 Mn 3 [Fe II (CN) 6 ] 2 exhibit extremely high stability under the acidic conditions of the gastric juice. Additionally, the high r 1 relaxivity, low toxicity, and high temporal stability of such NPs offer great potential for the development of a true T 1 -weighted oral contrast agent for MRI of the entire GI tract., (© 2021 Wiley-VCH GmbH.)