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Nanomaterials have small size and unique properties and are used as adsorbents in various fields. For biomaterials, it is necessary to use nanomaterials prepared from nontoxic molecules. Particularly, protein adsorption on hydroxyapatite, Ca 10 (PO 4 ) 6 (OH) 2 (HAp), which is highly biocompatible and ecological, was thoroughly studied by varying the reaction conditions and controlling the crystal faces. We easily prepared two peptide-containing HAp (peptide-HAp) materials with high selectivity for protein adsorption. The morphologies and characteristics of the peptide-HAp composites were similar to those of raw HAp; however, the surface charge was significantly changed by increasing the amount of peptides. The amount of cytochrome c adsorbed on peptide-HAp containing poly(L-glutamic acid) and of bovine serum albumin adsorbed on poly(L-lysine)-containing HAp significantly increased compared to that on pure HAp. In addition, as the amount of peptides was increased, peptide-HAp showed improved selectivity for protein adsorption by electrostatic interaction between peptide-HAp and protein. Moreover, peptide-HAp could be reused at least five times in adsorption-desorption cycles, and it was expected that the materials could be used as adsorbents and in separation columns. [ABSTRACT FROM AUTHOR]

Abstract Unique hollow mesoporous silica particles (MSP) were synthesized using dual templates. We focused on the synthesis of MSP using templates with triblock copolymer P123 (P123) and various ionic liquid surfactants. Interestingly, when using ionic liquid surfactants with different head groups, the resulting products exhibited hollow, larger hollow, and sheet-like morphologies. We also demonstrate that hollow MSP with surface amino groups can be used for selective absorption of negatively charged organic substances. Graphical abstract fx1 Highlights • Mesoporous silica particles were synthesized by a dual template method. • Different templates produced hollow, larger hollow, and sheet-like morphologies. • MSP-1-NH 2 with surface amino groups selectively adsorbed fluorescein. [ABSTRACT FROM AUTHOR]

The reactions of newly designed lithiated triamidoamines Li3LR (R = iPr, Pen, and Cy2) with VCl3(THF)3 under N2 yielded dinitrogen–divanadium complexes with a μ-N2 between vanadium atoms [{V(LR)}2(μ-N2)] (R = iPr (1) and Pen (2)) for the former two, while not dinitrogen–divanadium complexes but a mononuclear vanadium complex with a vacant site, [V(LCy2)] (R = Cy2 (3)), were obtained for the third ligand. The V–NN2 and N–N distances were 1.7655(18) and 1.219(4) Å for 1 and 1.7935(14) and 1.226(3) Å for 2, respectively. The ν(14N–14N) stretching vibrations of 1 and 2, as measured using resonance Raman spectroscopy, were detected at 1436 and 1412 cm–1, respectively. Complex 3 reacted with potassium metal in the presence of 18-crown-6-ether under N2 to give a hetero-dinuclear vanadium complex with μ-N2 between vanadium and potassium, [VK(LCy2)(μ-N2)(18-crown-6)] (4). The N–N distance and ν(14N–14N) stretching for 4 were 1.152(3) Å and 1818 cm−1, respectively, suggesting that 4 is more activated than complexes 1 and 2. The complexes 1, 2, 3, and 4 reacted with HOTf and K[C10H8] to give NH3 and N2H4. The yields of NH3 and N2H4 (per V atom) were 47 and 11% for 1, 38 and 16% for 2, 77 and 7% for 3, and 80 and 5% for 4, respectively, and 3 and 4, which have a ligand LCy2, showed higher reactivity than 1 and 2. [ABSTRACT FROM AUTHOR]

We recently reported the syntheses, crystal structures, and protonation reactions of dinitrogen divanadium complexes bearing triamidoamine ligands, ([{V(LR)}2(µ‐N2)] (R = iBu (1), EtBu (2), and iPr2Bn (3)). In this study, we have additionally synthesized two novel dinitrogen‐divanadium complexes with similar derivatives (R = Bn (4) and MeBn (5)), which are characterized spectroscopically and structurally. The X‐ray structures have both revealed a divanadium complex with a bridging N2 ligand. The protonation reactions of the µ‐N2 ligands for 4 and 5 in the presence of M+[C10H8]– (M+ = Na+, K+) and proton source (HOTf or [LutH](OTf)) have given ammonia. Particularly, the NH3 yield from the reaction of 5 with K+[C10H8]– and [LutH](OTf) has been 341 %. Furthermore, mixed valence Na+ adduct of 1, [Na{V(LiBu)}2(µ‐N2)] (6), which is prepared by the reaction of 1 with sodium metal, has been prepared and its crystal structure has also been determined. Compound 6 is electrochemically and spectroscopically characterized, which is also evaluated by DFT calculation method. [ABSTRACT FROM AUTHOR]

Techniques harnessing the strong interactions of the avidin–biotin system are frequently used in biosensing and protein separation. Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) is a calcium phosphate compound known to have a strong affinity for various proteins. In this study, the adsorption ability of avidin on composites and its binding activity to biotin were investigated using two types of poly(l-glutamic acid)-containing calcium phosphate composites (pGlu-HAp). The morphologies of pGlu-HAp including poly(α-glutamic acid) and poly(γ-glutamic acid) showed plate-like and sheet-like particles, respectively, due to the effects of the peptide structure. Furthermore, these particles exhibited the high adsorption capacity of avidin; the maximum adsorption amounts for poly(α-glutamic acid)-HAp and poly(γ-glutamic acid)-HAp were 776 and 302 μg mg−1 HAp, respectively. In addition, the equilibrium data for the adsorption of avidin on two pGlu-HAp-fitted Langmuir isotherm models correspond to a monolayer. The difference in the amount of adsorbed avidin on the two pGlu-HAp composites was influenced by the density of the carboxyl groups in pGlu-HAp. This revealed that avidin adsorbed on pGlu-HAp was able to bind four biotin molecules, and biotinylated protein was separated from protein mixtures by avidin-adsorbed pGlu-HAp. These results indicate that these particles would be appropriate in the development of biosensing and bioseparation tools. [ABSTRACT FROM AUTHOR]