A powerful combinatorial screen to identify high-affinity terbium(III)-binding peptides

Lanthanide-binding tags (LBTs) are protein fusion partners consisting of encoded amino acids that bind lanthanide ions with high affinity. Herein, we present a new screening methodology for the identification of new LBT sequences with high affinity for Tb(3+) ions and intense luminescence properties. This methodology utilizes solid-phase split-and-pool combinatorial peptide synthesis. Orthogonally cleavable linkers allow an efficient two-step screening procedure. The initial screen avoids the interference caused by on-bead screening by photochemically releasing a portion of the peptides into an agarose matrix for evaluation. The secondary screen further characterizes each winning sequence in a defined aqueous solution. Employment of this methodology on a series of focused combinatorial libraries yielded a linear peptide sequence of 17 encoded amino acids that demonstrated a 140-fold increase in affinity (57 nM dissociation constant, K(D)) over previously reported lanthanide-binding peptides. This linear sequence was macrocyclized by introducing a disulfide bond between flanking cysteine residues to produce a peptide with a 2-nM apparent dissociation constant for Tb(3+) ions.Supporting information for this article is available on the WWW under http://www.chemphyschem.org or from the author.     

Extraction of Lanthanides(III) by a Mixture of a Malonamide and a Dialkyl Phosphoric Acid

Several hydrometallurgical processes studied in France for lanthanide/minor actinide separation use a combination of DMDOHEMA and HDEHP as extractants. Although these processes have proved to be reliable, the modeling of their extraction properties remains a difficult task due to a lack of knowledge about the behavior of the mixed DMDOHEMA-HDEHP organic phase. In the present work, it was found that the solvent extraction of Ln(III) ions by a mixture of these extractants exhibits a complex behavior involving a synergistic effect at either 1 M HNO₃ or high metal concentration, and an antagonistic effect on extraction of metal traces at higher pH (> 2). To understand these effects, Ln(III) complexes formed after extraction by DMDOHEMA and/or HDEHP were characterized by several spectroscopic techniques (FT-IR, UV-Vis, ESI-MS, TRLIFS). Results suggested formation of DMDOHEMA-HDEHP adducts and ternary mixed complexes involving both extractants and possibly a nitrate ion.     

Fractionation of Rare Earth Elements in Plants Ⅰ. Fractionation Patterns and Their Forming Mechanisms in Different Organs of Triticum Aestivum

Rareearthelements(REEs)havetworemarka blecharacteristics:firstly,REEshaveverysimilar chemicalbehaviorsthatimpartcoherencyingeo chemicalprocesses;secondly,slightbutsystemic differencesofchemicalbehaviorsexistamongthem andtheytendtofractionateinsomenatura…     

808‐nm‐Light‐Excited Lanthanide‐Doped Nanoparticles: Rational Design,Luminescence Control and Theranostic Applications

808 nm‐light‐excited lanthanide (Ln³⁺)‐doped nanoparticles (LnNPs) hold great promise for a wide range of applications, including bioimaging diagnosis and anticancer therapy. This is due to their unique properties, including their minimized overheating effect, improved penetration depth, relatively high quantum yields, and other common features of LnNPs. In this review, the progress of 808 nm‐excited LnNPs is reported, including their i) luminescence mechanism, ii) luminescence enhancement, iii) color tuning, iv) diagnostic and v) therapeutic applications. Finally, the future outlook and challenges of 808 nm‐excited LnNPs are presented.     

Recent Progress in Time‐Resolved Biosensing and Bioimaging Based on Lanthanide‐Doped Nanoparticles

Luminescent nanomaterials have attracted great attention in luminescence‐based bioanalysis due to their abundant optical and tunable surface physicochemical properties. However, luminescent nanomaterials often suffer from serious autofluorescence and light scattering interference when applied to complex biological samples. Time‐resolved luminescence methodology can efficiently eliminate autofluorescence and light scattering interference by collecting the luminescence signal of a long‐lived probe after the background signals decays completely. Lanthanides have a unique [Xe]4f^N electronic configuration and ladder‐like energy states, which endow lanthanide‐doped nanoparticles with many desirable optical properties, such as long luminescence lifetimes, large Stokes/anti‐Stokes shifts, and sharp emission bands. Due to their long luminescence lifetimes, lanthanide‐doped nanoparticles are widely used for high‐sensitive biosensing and high‐contrast bioimaging via time‐resolved luminescence methodology. In this review, recent progress in the development of lanthanide‐doped nanoparticles and their application in time‐resolved biosensing and bioimaging are summarized. At the end of this review, the current challenges and perspectives of lanthanide‐doped nanoparticles for time‐resolved bioapplications are discussed.     

Solvent Extraction of Some Lanthanides with Trioctylphosphine Oxide in Molten Paraffin Wax

TOPO has been applied to tiranium separation[l]. Some fundamental investigations for uranium extraction have also been well done [2, 3].However little data have been reported for theextraction of lanthanides with TOPO. Ceccoine[4] reported the lanthanides extraction withTOPO in chloroform at 25 C. Other authors stUdied the synergistic extraction of lanthanides byusing TOPO as a neutral adducts [5].For the past decade, the method using themolten paraffin wax as a diluent for the lanthan…     

Solvent extraction of the trivalent lanthanides and yttrium by mixtures of 3,5-diisopropylsalicylic acid and neutral organophosphorus compounds

Neutral organophosphorus compounds containing a phosphoryl or thiophosphoryl group were found to cause appreciable synergistic shifts in the pH₅₀ values for the extraction of the trivalent lanthanides and yttrium from chloride media by solutions of 3,5-diisopropylsalicylic acid (DIPSA) in xylene. For the series of compounds with R = n-butyl, the synergistic effect increases in the order (RO)₃PS < (RO)₃PO < (RO)₂RPO < (RO)R₂PO < R₃PO. The synergistic effects are greater for lutetium(III) than for lanthanum(III) and, as a result, the separation across the lanthanide series (pH–pH) increases from only 0·17 pH unit for 0·25 M DIPSA alone to, for example, 0·85 pH unit for a mixture of 0·25 M DIPSA and 0·25 M triisobutylphosphine oxide (TIBPO). Mixtures of DIPSA and TIBPO give somewhat better separation factors between the light and middle lanthanide fractions (β = 3·0) than the commercial Versatic 10 acid (β = 2·6), and separation factors comparable to those of the latter extractant between the heaviest lanthanides (thulium to lutetium).     

Synthesis and Characterization of Nanocrystalline Lanthanide Oxysulfide via a La(OH)3 Gel Solvothermal Route

A La(OH)₃ gel solvothermal process has been developed for the preparation of nanocrystalline lanthanide oxysulfide (La₂O₂S) in polar solvents at 300°C through a reaction between a La(OH)₃ gel and K₂S. X-ray powder diffraction (XRD) indicated that the product was hexagonal La₂O₂S with cell parameters a = 4.046 Å and c = 6.951 Å. Transmission electronic microscopy (TEM) showed that different morphology nanocrystallites were formed, including particles with diameters of about 10 nm and nanorods about 10 nm in diameter and 300 nm in length, depending on the solvent.