Self-assembled rosette nanotubes from tetra guanine-cytosine modules.

Self-assembly of small molecules into supramolecular architectures is a sustainable alternative to new advanced material design. Herein, the design and synthesis of a self-assembling system containing four covalently linked hybrid guanine and cytosine (G∧C) units that were connected through bifunctional amines are reported. These tetra G∧C motifs were characterized and self-assembled in water and methanol to produce discrete nanostructures.

Delivery of siRNA using cationic rosette nanotubes for gene silencing.

The quest for new therapeutic treatments for hereditary diseases has led to many advances in RNA interference (RNAi) and gene silencing. While this technique has the potential to address many problems, the key to its continued use is the development of effective delivery strategies that would reduce cellular toxicity and increase silencing efficiency. Rosette nanotubes (RNTs) are biomimetic supramolecular nanostructures formed through the self-assembly of hybrid guanine-cytosine (G∧C) DNA bases.

Cellular Delivery of Plasmid DNA into Wheat Microspores Using Rosette Nanotubes.

Plant genetic engineering offers promising solutions to the increasing demand for efficient, sustainable, and high-yielding crop production as well as changing environmental conditions. The main challenge for gene delivery in plants is the presence of a cell wall that limits the transportation of genes within the cells. Microspores are plant cells that are, under the right conditions, capable of generating embryos, leading to the formation of haploid plants.

Facile Synthesis of Calcium Hydroxide Nanoparticles onto TEMPO-Oxidized Cellulose Nanofibers for Heritage Conservation.

Calcium hydroxide is used in diverse applications including heritage conservation where supplying it in the form of nanoparticles allows easy carbonation with atmospheric air contacts. The effects of cellulose nanofibers on the precipitation of calcium hydroxide nanoparticles were investigated by varying the reaction time, concentration, and carboxylation content of cellulose nanofibers. Cellulose nanofibers were very effective in producing calcium hydroxide nanoparticles with less than 50 nm sizes out of calcium nitrate-sodium hydroxide precipitation reactions.

Preparation of cellulose nanofibers by TEMPO-oxidation of bleached chemi-thermomechanical pulp for cement applications.

Hardwood bleached chemi-thermomechanical pulp (BCTMP) was converted to cellulose nanofibers by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) catalyzed oxidization along with mechanical defibrillation process. The TEMPO reaction was evaluated based on the delignification, carboxylate content of cellulose and the yield of the insoluble component. Cellulose nanofibers were characterized by conductometry, Fourier transform infrared spectroscopy (FT-IR), scanning electronic microscopy (SEM), thermogravimetric analysis (TGA) as well as X-ray diffraction (XRD) techniques.

High Field Solid-State NMR Spectroscopy Investigation of (15)N-Labeled Rosette Nanotubes: Hydrogen Bond Network and Channel-Bound Water.

(15)N-labeled rosette nanotubes were synthesized and investigated using high-field solid-state NMR spectroscopy, X-ray diffraction, atomic force microscopy, and electron microscopy. The results established the H-bond network involved in the self-assembly of the nanostructure as well as bound water molecules in the nanotube's channel.

Chiromers: conformation-driven mirror-image supramolecular chirality isomerism identified in a new class of helical rosette nanotubes.

Rosette nanotubes are biologically inspired nanostructures, formed through the hierarchical organization of a hybrid DNA base analogue (G∧C), which features hydrogen-bonding arrays of guanine and cytosine. Several twin-G∧C motifs functionalized with chiral moieties, which undergo a self-assembly process under methanolic and aqueous conditions to produce helical rosette nanotubes (RNTs), were synthesized and characterized. The built-in molecular chirality in the twin-G∧C building blocks led to the supramolecular chirality exhibited by the RNTs, as evidenced by the CD activity.

Self-adaptive hydrophilic and coordinating Teflon surfaces through a straightforward physisorption process.

Teflon surfaces exhibiting self-adaptive behaviour with both highly hydrophilic character and strong coordinating properties are prepared in a straightforward manner by physisorption of the fluorophilic copper(II)-carboxylate complex 2.

A triblock fluorous surfactant as a specific gelator for perfluorocarbons.

The fluorinated double-tailed triblock surfactant 1-Na represents a new type of gelator for perfluorocarbons which can gelate at low concentration (1.5 wt%) both bromoperfluorooctane and perfluorodecalin, two of the most appealing perfluorinated fluids for pharmaceutical applications.

Fluorous phase-switching of pyridyl-tagged substrates/products.

A bis-monopyridyl Wang-type tag was prepared for application in the hydrocarbon/perfluorocarbon phase-switching of substrates/products. This "catch-and-release" strategy relies on the reversible coordination of the tag to a fluorous copper(II)-carboxylate complex. A hydantoin was prepared in high yield and purity by a four-step protocol where the intermediates were purified by the straightforward liquid/liquid phase-switching process.

The pyridyl-tag strategy applied to the hydrocarbon/perfluorocarbon phase-switching of a porphyrin and a fullerene.

A new hydrocarbon/perfluorocarbon phase-switching strategy based on coordination of pyridyl-tagged molecules to a highly fluorinated dicopper-carboxylate complex possessing two accessible axial coordination sites is described. When a chloroform solution of the tetrapyridyl-substituted porphyrin 3 (0.1 mM, 2 mL) is layered on a perfluorodecalin solution of 2 (3.