Bis-(1,2,4-triazin-3-yl) ligand structure driven selectivity reversal between Am3+ and Cm3+: solvent extraction and DFT studies.

Selectivity between Am3+ and Cm3+ was investigated after their aqueous complexation with three structurally tailored hydrophilic bis-(1,2,4-triazin-3-yl) ligands followed by their extraction with N,N,N'N'-tetraoctyl diglycolamide (TODGA) dissolved in an ionic liquid (C4mim·Tf2N). The three hydrophilic ligands used were SO3PhBTP, SO3PhBTBP, and SO3PhBTPhen. It was evident from the solvent extraction studies that SO3PhBTP formed a stronger complex with Cm3+ than with Am3+, but SO3PhBTPhen showed better complexation ability for Am3+ than for Cm3+, and SO3PhBTBP showed no selectivity for the two actinide ions. DFT calculations indicated that the coordinating 'N' atoms in BTP were more co-planar in the complex and this co-planarity was higher in the Cm3+ complex as compared to that in Am3+. In the case of BTBP and BTPhen ligands, on the other hand, the co-planarity was more pronounced in the Am3+ complexes. Mayer's bond order calculations of M-N bonds in the complexes also indicated a reversal of the complexation ability of the BTP and BTPhen ligands for Am3+ and Cm3+. Calculations of the complexation energies further supported the higher selectivity of the BTP ligand for Am3+ by -52.0 kJ mol-1, and better selectivity of the BTPhen ligand for Cm3+ by -24.7 kJ mol-1.

Hydrophobic structural modification of chitosan and its impact on nanoparticle synthesis - A physicochemical study.

Chitin is a naturally occurring fully N-acylated biopolymer which cannot be converted into nanomaterial easily due to its inherent rigidity and chemical inertness. These properties limit the utility of chitin in nanomaterial-based applications. Therefore, our aim in the present work was, to prepare chitin like fully N-acylated derivatives with a hydrophobic moiety and study the impact on nanoparticles synthesis. We report such a fully substituted derivative, N-(Thiophene-2-acetyl)chitosan, its characterization and physicochemical studies of the nanoparticles synthesized. The study confirms that the hydrophobic structural modification of chitosan improves the processability of the material and defines the nanoparticles synthesis. This kind of organic nanoparticles, stable under wide pH range due to amine group protection of chitosan, can be used as nano- reinforcement material to enhance the properties of various composites.

Synthesis and Characterization of Surface Modified, Fluorescent and Biocompatible ZnS Nanoparticles with a Hydrophobic Chitosan Derivative.

The introduction of a hydrophobic moiety on chitosan enhances the self-assembling properties, mucoadhesion, the permeability of the macromolecule and aids in target specific delivery. Our group synthesized a hydrophobic trans N-(6,6-Dimethyl-2-hepten-4-ynyl)chitosan derivative (CSD) and studied the surface modification of ZnS nanoparticles in a single pot reaction. X-ray diffraction studies and FESEM imaging confirms the nano size and morphology of the surface modified Zinc sulfide nanoparticles (ZnS-CSD NPs). The proposed ZnS-CSD NPs showed excellent emission at 457 nm. Photostability studies indicate that the surface modified ZnS-CSD NPs possess better photostability than Rhodamine B and FITC. Cell viability tests confirmed the biocompatibility of the modified nanoparticles. All these features of ZnS- CSD NPs makes these candidates an excellent choice in a wide range of in vitro or in vivo studies as fluorescent biological labels.

Synthesis of Hexagonal ZnO-PQ7 Nano Disks Conjugated with Folic Acid to Image MCF - 7 Cancer Cells.

Surface modified ZnO nanomaterial is widely used in the field of bioimaging worldwide due to its optical properties, electronic characteristics and biocompatibility. Fluorescent enhanced, Polyquaternium-7(PQ7) capped, ZnO hexagonal nano disks (ZnO-PQ7) were synthesised by simple wet chemical method. The structural and optical properties of ZnO-PQ7 hexagonal nano disks were characterized using XRD, UV-Visible, Fluorescence, HRTEM, EDAX and FTIR studies. The size of synthesised ZnO-PQ7 were around 30-45 nm as confirmed by HRTEM studies. Fluorescence emission intensity increased with increase in PQ7 concentration. ZnO-PQ7 was further conjugated with folic acid (FA) to target human breast cancer cell line (MCF-7) via EDC/NHS coupling chemistry. Conjugation of folic acid with ZnO-PQ7 was confirmed by FTIR studies. The cell viability study using Methyl thiazolyltetrazolium(MTT) assay has demonstrated that the ZnO-PQ7 conjugated FA composites (ZnO-PQ7-FA) exhibit low toxicity towards MCF-7 up to a concentration of 125 µg/mL. Confocal laser scanning microscopic images confirmed the uptake of ZnO-PQ7-FA nanoparticles by MCF-7 cells. This study reveals ZnO-PQ7-FA nano disks as a potential imaging agent for detection of cancer cells. The synthesis route reported in this article is simple and easy to follow for the synthesis of ZnO-PQ7-FA in bulk quantities with high purity.