Albumin and Hyaluronic Acid-Coated Superparamagnetic Iron Oxide Nanoparticles Loaded with Paclitaxel for Biomedical Applications.

Super paramagnetic iron oxide nanoparticles (SPION) were augmented by both hyaluronic acid (HA) and bovine serum albumin (BSA), each covalently conjugated to dopamine (DA) enabling their anchoring to the SPION. HA and BSA were found to simultaneously serve as stabilizing polymers of Fe3O4·DA-BSA/HA in water. Fe3O4·DA-BSA/HA efficiently entrapped and released the hydrophobic cytotoxic drug paclitaxel (PTX). The relative amount of HA and BSA modulates not only the total solubility but also the paramagnetic relaxation properties of the preparation. The entrapping of PTX did not influence the paramagnetic relaxation properties of Fe3O4·DA-BSA. Thus, by tuning the surface structure and loading, we can tune the theranostic properties of the system.

Investigation of VO-salophen complexes electronic structure.

Vanadyl N,N'-bis(salicylidene)-o-phenylenediamine (salophen) complexes have been extensively investigated by cyclic voltammetry, UV-visible spectroscopy and theoretical calculations in MeCN, THF (tetrahydrofuran) and DMF (N,N-dimethylformamide), in order to elucidate the overall factors that influence the electronic density of the metal and therefore the properties of these complexes in various applications. Different substituents were introduced into the salophen skeleton to change the vanadium electron density. Results obtained and here presented showed that the substituents influence the metal electronic character in a way that cannot be easily predicted by considering only the electronic effect. Similarly, the solvent polarity or coordination ability affects the metal complex properties in an unpredictable way. Therefore, experimental and theoretical data here collected are a powerful tool to a priori design salophen ligands to obtain vanadyl complexes having the specific electronic properties suitable for desired applications.

Conformational changes of 1-4-glucopyranosyl residues of a sulfated C-C linked hexasaccharide.

This work describes the structure of a fully sulfated maltotriose alpha-beta C-C linked dimer, where a central glycosidic bond was substituted by a non natural, hydrolase-resistant C-C bond. Such compound shows anti-metastatic properties being an inhibitor of the heparanase enzymatic activity and of P-selectin-mediated cell-cell interactions. NMR spectroscopy was applied to investigate the structure and conformational properties of this C-C linked hexasaccharide. The presence of sulfate substituents and the internal C-C bond drives the two internal rings in an unusual (1)C(4) chair conformation, while the external rings linked by glycosidic bonds retain the typical (4)C(1) conformation. The NMR results were confirmed by molecular mechanics calculations using structure corresponding di- and tetrasaccharides as models.

Non-covalent synthesis of metal oxide nanoparticle-heparin hybrid systems: a new approach to bioactive nanoparticles.

Heparin has been conjugated to Fe3O4, Co3O4, and NiO nanoparticles (NPs) through electrostatic interactions, producing colloidal suspensions of hybrid metal oxide heparin NPs that are stable in water. Negative zeta potentials and retention of heparin's ability to capture toluidine blue indicate that heparin's negative charges are exposed on the surface of the coated NPs. IR results confirmed the formation of nanohybrids as did NMR experiments, which were also interpreted on the basis of toluidine blue tests. Transmission electron microscopy results revealed that the heparin coating does not modify the shape or dimension of the NPs. Dynamic light scattering and negative zeta potential measurements confirmed that heparin surface functionalisation is an effective strategy to prevent NP aggregation.

Posidonia oceanica as a Renewable Lignocellulosic Biomass for the Synthesis of Cellulose Acetate and Glycidyl Methacrylate Grafted Cellulose.

High-grade cellulose (97% α-cellulose content) of 48% crystallinity index was extracted from the renewable marine biomass waste Posidonia oceanica using H2O2 and organic peracids following an environmentally friendly and chlorine-free process. This cellulose appeared as a new high-grade cellulose of waste origin quite similar to the high-grade cellulose extracted from more noble starting materials like wood and cotton linters. The benefits of α-cellulose recovery from P. oceanica were enhanced by its transformation into cellulose acetate CA and cellulose derivative GMA-C. Fully acetylated CA was prepared by conventional acetylation method and easily transformed into a transparent film. GMA-C with a molar substitution (MS) of 0.72 was produced by quenching Fenton's reagent (H2O2/FeSO4) generated cellulose radicals with GMA. GMA grafting endowed high-grade cellulose from Posidonia with adsorption capability. GMA-C removes ß-naphthol from water with an efficiency of 47%, as measured by UV-Vis spectroscopy. After hydrolysis of the glycidyl group to glycerol group, the modified GMA-C was able to remove p-nitrophenol from water with an efficiency of 92%, as measured by UV-Vis spectroscopy. α-cellulose and GMA-Cs from Posidonia waste can be considered as new materials of potential industrial and environmental interest.

Anti-metastatic semi-synthetic sulfated maltotriose C-C linked dimers. Synthesis and characterisation.

This manuscript describes the preparation and the spectroscopic characterisation of semi-synthetic sulfated maltotriose C-C linked dimers (SMTCs) where the natural C-O-C anomeric bond was substituted by one direct central C-C bond. This C-C bond induces conformation and flexibility changes with respect to the usual anomeric bond. SMTCs neutral precursors came from maltotriosyl bromide electroreduction through maltotriosyl radical intermediate dimerisation. The new C-C bond configuration, named for convenience α,α, α,ß and ß,ß as the natural anomeric bond, dictated the statistic ratio formation of three diastereoisomers. They were separated by silica gel flash chromatography followed by semi preparative HPLC chromatography. Each diastereoisomer was exhaustively sulfated to afford the corresponding SMTCs. SMTCs were huge characterised by NMR spectroscopy which provided the sulfation degree, too. α,α and α,ß were found quite homogeneous samples with a high degree of sulfation (85-95%). ß,ß appeared a non-homogeneous sample whose average sulfation degree was evaluated at around 78%. Mass spectroscopy experiments confirmed the sulfation degree range. Some considerations were proposed about SMTCs structure-biological properties.

Unexpected one-pot synthesis of highly conjugated pentacyclic diquinoid compounds.

A new class of pentacyclic diquinoid compounds has been synthesized with a facile one-pot reaction of two molecules of 2-hydroxynaphthoquinone and 1-bromoalkanes in the presence of ferrocene. These molecules were isolated as enol tautomers that exhibit intramolecular hydrogen bond and extended electronic conjugation as proved by the intense absorption spectrum with a broad band between 400 and 600 nm. The spectroscopic and electrochemical characterization of this new class of compounds has been performed. One of the synthesized diquinoid derivatives showed a significant cytotoxicity with IC(50) values of 25-50 µM against Cisplatin-Resistant SKOV3 and colon carcinoma SW480 cell lines. The results of our study provide a valuable tool to a one-pot synthesis of highly conjugated polyquinones, analogous to important biological systems, with significant antitumoral activity.