Killing with light: A multifunctional nanosized zeolite L uses amino groups, a luminescent dye, and a 1O2 producer to target, label, and kill pathogenic and antibiotic‐resistant bacteria.

Novel 2-(1-substituted-1H-1,2,3-triazol-4-yl)pyridine (pytl) ligands have been prepared by "click chemistry" and used in the preparation of heteroleptic complexes of Ru and Ir with bipyridine (bpy) and phenylpyridine (ppy) ligands, respectively, resulting in [Ru(bpy)(2)(pytl-R)]Cl(2) and [Ir(ppy)(2)(pytl-R)]Cl (R=methyl, adamantane (ada), beta-cyclodextrin (betaCD)). The two diastereoisomers of the Ir complex with the appended beta-cyclodextrin, [Ir(ppy)(2)(pytl-betaCD)]Cl, were separated. The [Ru(bpy)(2)(pytl-R)]Cl(2) (R=Me, ada or betaCD) complexes have lower lifetimes and quantum yields than other polypyridine complexes. In contrast, the cyclometalated Ir complexes display rather long lifetimes and very high emission quantum yields. The emission quantum yield and lifetime (Phi=0.23, tau=1000 ns) of [Ir(ppy)(2)(pytl-ada)]Cl are surprisingly enhanced in [Ir(ppy)(2)(pytl-betaCD)]Cl (Phi=0.54, tau=2800 ns). This behavior is unprecedented for a metal complex and is most likely due to its increased rigidity and protection from water molecules as well as from dioxygen quenching, because of the hydrophobic cavity of the betaCD covalently attached to pytl. The emissive excited state is localized on these cyclometalating ligands, as underlined by the shift to the blue (450 nm) upon substitution with two electron-withdrawing fluorine substituents on the phenyl unit. The significant differences between the quantum yields of the two separate diastereoisomers of [Ir(ppy)(2)(pytl-betaCD)]Cl (0.49 vs. 0.70) are attributed to different interactions of the chiral cyclodextrin substituent with the Delta and Lambda isomers of the metal complex.

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Allergic reactions towards β-lactam antibiotics pose an important clinical problem. The ability of small molecules, such as a β-lactams, to bind covalently to proteins, in a process known as haptenation, is considered necessary for induction of a specific immunological response. Identification of the proteins modified by β-lactams and elucidation of the relevance of this process in allergic reactions requires sensitive tools. Here we describe the preparation and characterization of a biotinylated amoxicillin analog (AX-B) as a tool for the study of protein haptenation by amoxicillin (AX). AX-B, obtained by the inclusion of a biotin moiety at the lateral chain of AX, showed a chemical reactivity identical to AX. Covalent modification of proteins by AX-B was reduced by excess AX and vice versa, suggesting competition for binding to the same targets. From an immunological point of view, AX and AX-B behaved similarly in RAST inhibition studies with sera of patients with non-selective allergy towards β-lactams, whereas, as expected, competition by AX-B was poorer with sera of AX-selective patients, which recognize AX lateral chain. Use of AX-B followed by biotin detection allowed the observation of human serum albumin (HSA) modification by concentrations 100-fold lower that when using AX followed by immunological detection. Incubation of human serum with AX-B led to the haptenation of all of the previously identified major AX targets. In addition, some new targets could be detected. Interestingly, AX-B allowed the detection of intracellular protein adducts, which showed a cell type-specific pattern. This opens the possibility of following the formation and fate of AX-B adducts in cells. Thus, AX-B may constitute a valuable tool for the identification of AX targets with high sensitivity as well as for the elucidation of the mechanisms involved in allergy towards β-lactams.

Ruthenium metallosurfactant forms micelles that show efficient electronic energy-transfer processes in the presence of an analogous iridium complex. Modulation of the process is achieved upon incorporation of these amphiphiles into cetyltrimethylammonium bromide micelles, allowing a tuning of the two emissions.

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These results represent the first identification of AX-mediated haptenation of intracellular proteins. Moreover, they show that exosomes can constitute a novel vehicle for haptenated proteins, and raise the hypothesis that they could provide antigens for activation of the immune system during the allergic response.