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Antimicrobial photodynamic therapy offers significant benefits over standard antibiotic therapy in terms of rapid sterilization and resistance reduction. In this paper, a series of ruthenium complexes were designed and synthesized for antibacterial studies. [Ru(tpy)(dppz-R)Cl][PF6] (tpy = 2,2′:6′,2′′-terpyridine; dppz = dipyrido [3,2-a:2′,3′-c] phenazine; R = H, CH3, C(CH3)3, F, CF3, NO2, NH2 or CN), Ru1–Ru8 all showed superior in vitro antimicrobial effects under blue light irradiation. Ru2 has the best antimicrobial activity, with its inherent dark toxicity and photodynamic inactivation rapidly killing S. aureus without developing drug tolerance. Binding and damaging DNA as well as generating ROS may be its potential antimicrobial targets. Ru2 lacks a hemolytic effect on rabbit erythrocytes and has low phototoxicity against G. mellonella Larvae. In addition, Ru2 has been successfully used to treat skin wounds in mice infected with S. aureus. Therefore, Ru2 has shown great potential as a photodynamic antimicrobial agent against the threat of S. aureus infection. [ABSTRACT FROM AUTHOR]

The diversity of catalytic activities and antioxidant properties of cerium oxide nanoparticles (CeO2 NPs) makes them promising materials for the theranostics of various diseases, especially those caused by disturbances in free radical homeostasis in living systems. Despite the fact that the functionalisation of nanoparticles' surface plays a critical role in nanomedicine applications, the effect of different coatings on their enzyme-like behaviour and antioxidant properties is still poorly understood, which limits the biomedical application of CeO2 NPs. This paper reports on the effect of low and high molecular weight biocompatible ligands on the SOD-like activity and radical scavenging properties of CeO2 NPs, which was analysed using a phosphate-rich medium resembling a natural environment. The results obtained show that these ligands modulate the SOD-like properties of CeO2 NPs as follows. Citrate and polysaccharide (maltodextrin and dextran) surface coatings increase the SOD-like activity of CeO2 NPs by an average of 2.2 times, and the protein corona (γ-globulin, γ-IgG) increases this activity by an average of 1.8 times. Citrate-coated CeO2 NPs and CeO2 nanoparticles modified with polysaccharide molecules are more effective SOD mimetics than CeO2@γ-IgG NPs. The SOD-like activity of phosphatidylcholine-coated CeO2 and CeO2@γ-IgG NPs is due to the combined action of nanoscale CeO2 and ligands. The antioxidant activity of CeO2 NPs after their modification with different ligands with respect to alkyl peroxyl radicals is multidirectional. Unexpectedly, citrate-, maltodextrin- and dextran-coated CeO2 NPs are more effective antioxidants than bare CeO2 NPs. CeO2 NPs modified with phosphatidylcholine or γ-IgG exhibited less radical-scavenging ability than bare CeO2 nanoparticles. Thus, common biocompatible ligands are able to regulate the biochemical activity of CeO2 NPs. [ABSTRACT FROM AUTHOR]

The π⋯π interactions in spin crossover (SCO) complexes can be used as an important means to fine-tune the spin transition behaviors. In this paper, three novel isostructural 2D Hofmann-type frameworks, [Fe(ppo)2M(CN)4] (1, M = Pt2+; 2, M = Pd2+; 3, M = Ni2+) have been successfully synthesized by judiciously choosing a large conjugated molecule, 2-(2-pyridyl)-5-(4-pyridyl)-1,3,4-oxadiazole (ppo) as the axial ligand. Single crystal X-ray crystallography analysis showed that there are different π⋯π interactions between the axial ppo ligands in 1–3. Variable temperature magnetic susceptibility studies revealed that 1 and 3 displayed incomplete and gradual SCO behaviors with T1/2 = 94 and 78 K, respectively, while 2 stayed in a high-spin state in the measured temperature range. The stronger π⋯π interactions between the conjugated ppo ligands observed in 1 and 3 than those in 2 may result in their different magnetic behaviors. [ABSTRACT FROM AUTHOR]

In this study, we synthesized two unsymmetrical and dipodal Schiff–Mannich combo ligands, namely benzoic acid (3-benzoimidazol-1-ylmethyl-2-hydroxy-5-methyl-benzylidene)-hydrazide (H2BBH) and the hydroxyl analogue 2-hydroxy-benzoic acid (3-benzoimidazol-1-ylmethyl-2-hydroxy-5-methyl-benzylidene)-hydrazide (H3BSH), for the selective detection of Zn2+ in semi-aqueous media. Both the probes selectively depict a turn-on response to Zn2+ as a result of the combined effect of chelation-induced enhanced fluorescence (CHEF) and photo-induced electron transfer (PET). Detailed experimental studies reveal that H2BBH and H3BSH can detect Zn2+ in solutions with limit of detections of 27 nM and 46 nM, respectively. The structures of probe-Zn2+ ensembles were proposed as [(HBBH)2Zn] and [(H2BSH)2Zn] by ESI-MS, FT-IR spectroscopy, 1H NMR titration and DFT/TD-DFT methods. Moreover, both the probes were successfully employed in the detection of Zn2+ in HuH-7 cells, seedlings of chickpea and mung beans, and paper strips. [ABSTRACT FROM AUTHOR]