In vitro detection of cancer cells using a novel fluorescent choline derivative.

Introduction: The treatment of preinvasive lesions is more effective than treating invasive disease, hence detecting cancer at its early stages is crucial. However, currently, available screening methods show various limitations in terms of sensitivity, specificity, and practicality, thus novel markers complementing traditional cyto/histopathological assessments are needed. Alteration in choline metabolism is a hallmark of many malignancies, including cervical and breast cancers.

Regioselectivity Control in Spirobifluorene Nitration under Mild Conditions: Explaining the Crivello's Reagent Mechanism.

The regioselective nitration of 9,9'-spirobifluorene under mild conditions is reported for the first time by operating under Menke's and Crivello's conditions. The optimized protocol allows obtaining 2-nitro and 2,2'-dinitro-9,9'-spirobifluorene in yields of 79 and 95% and, for the first time, 2,2',7-trinitro-9,9'-spirobifluorene with 66% yield. Besides, the role of dinitrate salt in Crivello's protocol has been now clarified, which opens novel scenarios in the preparation of functional materials.

Thermally Activable Bistetrazoles for Elastomers Crosslinking.

Sulfur vulcanization is the most used method for curing of natural and synthetic rubbers. The crosslinking degree achieved is usually controlled by adding proper quantities of accelerants, activators, co-activators, retardants, and inhibitors, and influences the hardness, elasticity, hysteresis of elastomers and, consequently, the properties and behavior of the materials that incorporate them. Despite the fine tuning pursued over the years, sulfur crosslinking is still difficult to control both in terms of degree and homogeneity of cross-link.

Pushing Down the Limit of NH Detection of Graphene-Based Chemiresistive Sensors through Functionalization by Thermally Activated Tetrazoles Dimerization.

An easy and cost-effective method is presented to functionalize graphene through thermally activated dimerization of 2,5-diaryltetrazoles. Consistently with the experimental spectroscopic results, theoretical calculations demonstrate that during the thermal treatment a dimerization process to tetrazine is energetically more favorable than covalent grafting. Since both the functionalization method by thermal activation and the use of tetrazoles have never been considered before to prepare graphene-based chemiresistors, this represents a promising approach to develop graphene-related sensing platforms.

Bypassing the statistical limit of singlet generation in sensitized upconversion using fluorinated conjugated systems.

The photon upconversion based on triplet-triplet annihilation (TTA) is a mechanism that converts the absorbed low-energy electromagnetic radiation into higher energy photons also at extremely low excitation intensities, but its use in actual technologies is still hindered by the limited availability of efficient annihilator moieties. We present here the results obtained by the synthesis and application of two new fluorinated chromophores based on phenazine and acridine structures, respectively. Both compounds show upconverted emission demonstrating their ability as TTA annihilator.

Morphological characterization and electronic properties of pristine and oxygen-exposed graphene nanoribbons on Ag(110).

Graphene nanoribbons (GNRs) are at the frontier of research on graphene materials since the 1D quantum confinement of electrons allows for the opening of an energy gap. GNRs of uniform and well-defined size and shape can be grown using the bottom-up approach, i.e.

Gelatin-Based Hydrogels through Homobifunctional Triazolinediones Targeting Tyrosine Residues.

Gelatin is a biopolymer with interesting properties that can be useful for biomaterial design for different applications such as drug delivery systems, or 3D scaffolds for tissue engineering. However, gelatin suffers from poor mechanical stability at physiological temperature, hence methods for improving its properties are highly desirable. In the present work, a new chemical cross-linking strategy based on triazolinedione ene-type chemistry towards stable hydrogel is proposed.

Synthesis of corrugated C-based nanostructures by Br-corannulene oligomerization.

The structure and electronic properties of carbon-based nanostructures obtained by metal surface assisted synthesis is highly dependent on the nature of the precursor molecule. Here, we report on a combined scanning tunneling microscopy, soft X-ray spectroscopy and density functional theory investigation on the surface assisted polymerization of Br-corannulene at Ag(110) and on the possibility of building a mesh of π-conjugated polymers starting from buckyball shaped molecules. Indeed, the corannulene units form one-molecule-wide ribbons in which the natural concavity of the precursor molecule is maintained.

Synthesis of graphene nanoribbons with a defined mixed edge-site sequence by surface assisted polymerization of (1,6)-dibromopyrene on Ag(110).

By a combination of scanning tunneling microscopy, X-ray spectroscopic techniques and density functional theory calculations, we prove the formation of extended patterns of parallel, graphene nanoribbons with alternate zig-zag and armchair edges and selected width by surface-assisted Ullmann coupling polymerization and dehydrogenation of 1,6-dibromopyrene (CHBr). Besides the relevance of these nanostructures for their possible application in nanodevices, we demonstrate the peculiarity of halogenated pyrene derivatives for the formation of nanoribbons, in particular on Ag(110). These results open the possibility of tuning the shape and dimension of nanoribbons (and hence the correlated electronic properties) by choosing suitably tailored or on-purpose designed molecular precursors.

On-surface photo-dissociation of C-Br bonds: towards room temperature Ullmann coupling.

The surface-assisted synthesis of gold-organometallic hybrids on the Au(111) surface both by thermo- and light-initiated dehalogenation of bromo-substituted tetracene is reported. Combined X-ray photoemission (XPS) and scanning tunneling microscopy (STM) data reveal a significant increase of the surface order when mild reaction conditions are combined with 405 nm light irradiation.

Control of the intermolecular coupling of dibromotetracene on Cu(110) by the sequential activation of C-Br and C-H bonds.

Dibromotetracene molecules are deposited on the Cu(110) surface at room temperature. The complex evolution of this system has been monitored at different temperatures (i.e.

CHOLINE TRANSPORTER-LIKE1 is required for sieve plate development to mediate long-distance cell-to-cell communication.

Phloem, a plant tissue responsible for long-distance molecular transport, harbours specific junctions, sieve areas, between the conducting cells. To date, little is known about the molecular framework related to the biogenesis of these sieve areas. Here we identify mutations at the CHER1/AtCTL1 locus of Arabidopsis thaliana.

Thiol-ene mediated neoglycosylation of collagen patches: a preliminary study.

Despite the relevance of carbohydrates as cues in eliciting specific biological responses, the covalent surface modification of collagen-based matrices with small carbohydrate epitopes has been scarcely investigated. We report thereby the development of an efficient procedure for the chemoselective neoglycosylation of collagen matrices (patches) via a thiol-ene approach, between alkene-derived monosaccharides and the thiol-functionalized material surface. Synchrotron radiation-induced X-ray photoelectron spectroscopy (SR-XPS), Fourier transform-infrared (FT-IR), and enzyme-linked lectin assay (ELLA) confirmed the effectiveness of the collagen neoglycosylation.

Polarized absorption, spontaneous and stimulated blue light emission of J-type tetraphenylbutadiene monocrystals.

Blue amplified spontaneous emission at room temperature is demonstrated from the exposed face of the strongly emitting organic semiconductor 1,1,4,4-tetraphenyl-1,3-butadiene in single crystal form. The symmetry of the crystal and calculation of lattice sums indicate the J-type organization of the molecular transition moments. The minimum in the lowest exciton dispersion branch, from which emission takes place, is found at the edge of the Brillouin zone leading to a dominant vibronic emission since the zero-phonon line is forbidden.

Hyaluronic acid in hydrophilic contact lenses: spectroscopic investigation of the content and release in solution.

Two experimental spectroscopic methods for the determination of the content of hyaluronic acid in solution are provided based on the formation of complexes between the hyaluronic acid and cationic dyes with sensitivity down to concentrations of either 0.25 or 2.5 microg/ml.

Organic-organic epitaxy of incommensurate systems: quaterthiophene on potassium hydrogen phthalate single crystals.

Hot-wall epitaxy and molecular-beam epitaxy have been employed for growing quaterthiophene thin films on the (010) cleavage face of potassium hydrogen phthalate, and the results are compared in terms of film properties and growth mode. Even if there is no geometrical match between substrate and overlayer lattices, these films are epitaxially oriented. To investigate the physical rationale for this strong orientation effect, optical microscopy, atomic force microscopy, and X-ray diffraction are employed.

Choline and phosphatidylcholine fluorescent derivatives localization in carcinoma cells studied by laser scanning confocal fluorescence microscopy.

In this study, we have shown the intracellular distribution of choline and phosphatidylcholine fluorescent derivatives in human breast carcinoma cells using confocal microscopy. The fluorescent choline derivatives ethanamimium 2-hydroxy-N,N-dimethyl-N-[2-N-(2,1,3-benzoxadiazol-4-amine,-N-methyl,-7- nitro)-ethyl] bromide (NBD-choline) and C(6)-NBD-phosphatidylcholine (C(6)-NBD-PC) were used in this work. NBD-choline was easily internalised into drug sensitive MCF-7 and in multidrug resistant MCF-7/DX cells.