The recent use of calcein (CA) as a fluorescent probe for cellular iron has been shown to reflect the nutritional status of iron in mammalian cells (Breuer, W., Epsztejn, S., and Cabantchik, Z. I. (1995) J. Biol. Chem. 270, 24209 -24215). CA was claimed to be a chemosensor for iron(II), to measure the labile iron pool and the concentration of cellular free iron(II). We first study here the thermodynamic and kinetic properties of iron binding by CA. Chelation of a first iron(III) involves one aminodiacetic arm and a phenol.

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Arsenic is one of the most hazardous pollutants, and is present in water, mainly, as As(V) and As(III), and in its inorganic hydrolysis species. Great efforts have been made to develop effective removal techniques. One alternative is the use of water‐soluble polymers containing functional groups to remove these toxic species. This paper presents the synthesis and characterization (FT‐IR and 1H NMR spectroscopy, as well as thermogravimetry TG‐DSC) of two cationic water‐soluble polymers containing tetra alkylammonium groups, poly[2‐(acryloyloxy)ethyl]trimethylammonium chloride, and poly[2‐acryloyloxy)ethyl]trimethylammonium methyl sulfate (P(SAETA)). The arsenate retention properties were investigated using the liquid‐phase polymer‐based retention technique. The polymer structure and the exchangeable anions' nature have been shown to be two important variables in the removal efficiency of arsenate anions from aqueous solutions. Both investigated polymers were found to efficiently remove HAsO42− species from an aqueous media, with pH ranging from 6 to 8. The exchange of methyl sulfate for the chloride anion on P(SAETA) improved arsenate ion retention ability. The modification of ionic strength by Na2SO4 addition induced a significant decrease in the cationic polymer's arsenate retention properties. The polymers' retention properties were not studied using real samples. POLYM. ENG. SCI., 47:1256–1261, 2007. © 2007 Society of Plastics Engineers

The complexation of FeIII by new tetradentate and pentadentate aminocarboxylate chelators, designed to protect cells against iron‐catalysed oxidative damage, was investigated. Ferric iron complexes of N,N′‐bis(3,4,5‐trimethoxybenzyl)ethylenediamine‐N,N′‐diacetic acid (L1), N,N′‐dibenzylethylenediamine‐N,N′‐diacetic acid (L2) and [N‐(2‐hydroxybenzyl)‐N′‐benzylethylenediamine‐N,N′‐diacetic acid] (L3) have been characterized in aqueous solution by potentiometric, UV/Vis spectrophotometric and cyclic voltammetric measurements. The parent ligand, ethylenediamine‐N,N′‐diacetic acid (L4), has also been studied. As expected, the presence of a hard phenolate donor group in L3 significantly enhances the affinity for iron while decreasing the potential of the FeIII/FeII redox couple compared to L1 or L2. Kinetics studies have provided the kinetic rate constants related to the formation and the dissociation of the ferric complex with L3. The results reveal a fast FeIII uptake, which is a favorable feature for a biological use of this type of ligand. Overall, these results demonstrate the pertinence of the use of such ligands to protect biological tissues against oxidative stress.