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The α-C-Glycoside of N-acetyllactosamine 8 was synthesised from lactose by acetylation, conversion into the allyl α-C-glycoside 4, exchanging the protecting groups for benzyl ethers, selective deprotection at the gluco-C-2 by iodocyclisation-reductive elimination, and conversion of the free hydroxyl group into an acetamido group by oxidation, oximation, stereoselective reduction and acetylation. Isomerization of the C-glycosidic appendage by conversion into a 2-oxypropyl group and treatment with base gave, after acetylation, the β-C-glycoside of N-acetyllactosamine 11.

A non natural glycosphingolipid containing the mucin derived, cancer associated disaccharide moiety Galβ1→3GalNAc, the T-antigen, α linked to a ceramide, has been synthesised via the protected disaccharide glycosyl trichloroacetimidate. The product has potential as a cancer vaccine.

The promising trends in biotechnology and tissue engineering are based on the development of advanced materials with biomimetic features in order to recreate the native environment promoting the appropriate cell behavior for tissue regeneration. Cell therapy together with novel functionalized biomaterials represent a very promising approach in regenerative medicine for cartilage regeneration. Articular cartilage exhibits a well-ordered organization with an extracellular matrix arranged as a network of collagen fibers and proteoglycans that allow for cell adhesion, mechanical support, transduction of chemical and mechanical signals from the surrounding tissue to the cells. Electrospun materials are considered highly promising scaffolds for cartilage tissue engineering given their specific fibrous morphology that resembles the fibrous component of tissue extracellular matrix. Many synthetic and natural polymers have been successfully electrospun to obtain scaffolds. Among natural polymers, collagen is universally applied as biomaterial in regenerative medicine because of its unique biocompatibility, and structural property. Robust techniques for surface “biodecoration” are currently required and the appropriate surface functionalization still remains a critical variable for the optimal performance of a wide range of biomaterials. Covalent bonding of bioactive molecules to material surface is a valid strategy in order to allow a sufficiently strong and specific affinity of biomolecules with the surface itself; in addition covalent bonding may permit site-directed immobilization and preservation of specific conformation and exposition to control biological responses. Plasma processes allow to tune surface properties of materials with negligible effect on their bulk. The need of improving cell/surface interaction has decisively introduced plasma techniques in the field of biomaterials; In addition, a wide range of compounds can be chosen as a monomer for plasma polymerization, providing a great diversity of possible surface modifications with different functional groups, including amine, anhydride, epoxide, carboxylic acid, cyano, halide, hydroxyl, furfuryl, and perfluoroalkyl.

The ability of gelatin-based hydrogels of incorporating and releasing under controlled conditions 5,6-dihydroxyindole-2-carboxylic acid (DHICA), a melanin-related metabolite endowed with marked antioxidant properties was investigated. The methyl ester of DHICA, MeDHICA, was also tested in view of its higher stability, and different solubility profile. Three types of gelatin-based hydrogels were prepared: pristine porcine skin type A gelatin (HGel-A), a pristine gelatin cross-linked by amide coupling of lysines and glutamic/aspartic acids (HGel-B), and a gelatin/chitosan blend (HGel-C). HGel-B and HGel-C differed in the swelling behavior, showed satisfactorily high mechanical strength at physiological temperatures and well-defined morphology. The extent of incorporation into all the gelatins tested using a 10% w/w indole to gelatin ratio was very satisfactory ranging from 60 to 90% for either indoles. The kinetics of indole release under conditions of physiological relevance was evaluated up to 72 h. The highest values were obtained with HGel-B and HGel-C for MeDHICA (90% after 6 h), and an appreciable release was observed for DHICA reaching 30% and 40% at 6 h for HGel-B and HGel-C, respectively. At 72 h, DHICA and MeDHICA were released at around 30% from HGel-A at pH 7.4, with an increase up to 40% at pH 5.5 in the case of DHICA. DHICA incorporated into HGel-B proved fairly stable over 6 h whereas the free compound at the same concentration was almost completely oxidized. The antioxidant power of the indole loaded gelatins was monitored by chemical assays and proved unaltered even after prolonged storage in air, suggesting that the materials could be prepared in advance with respect to their use without alteration of their efficacy.

Type I collagen films have been functionalized on their surfaces by plasma treatment with carboxyl and amino groups to improve their potential for grafting bioactive molecules. The physico-chemical properties of the plasma-treated films were evaluated and compared to the untreated materials by water contact angle, SEM and AFM. The presence of new functional groups on the film surfaces has been assessed by ATR-FTIR spectra after chemical derivatization. Moreover, the biocompatibility of the plasma-treated films was studied with MG-63 human osteoblast-like cells, evaluating cell proliferation, viability and morphology at 1, 3 and 7. days. © 2012 Elsevier Inc.

Molecular recognition of glycans plays an important role in glycomic and glycobiology studies. For example, pathogens have a number of different types of lectin for targeting host sugars. In bacteria, lectins exist sometimes as domains of bacterial toxins and exploit adhesion to glycoconjugates as a means of entering host cells. Herein, we describe the synthesis of three glycodendrons with the aim to dissect the fine structural details involved in the multivalent carbohydrate-protein interactions. LecA, from the pathogen Pseudomonas aeruginosa, has been used to characterize galactose dendrons interaction using one of the most widespread NMR technique for the elucidation of receptor-ligand binding in solution, the saturation transfer difference (STD) NMR. Furthermore, the effective hydrodynamic radius of each dendrimer recognized by LecA was estimated from the diffusion coefficients determined by pulsed-field-gradient stimulated echo (PFG-STE) NMR experiments.

The grafting of galactose units onto poly(epsilon-caprolactone) (PCL) substrates by a wet chemistry two-step procedure is proposed. Even though a reduction of hardness from 0.58-0.31 GPa to 0.12-0.05 GPa is achieved, the chemical functionalization does not negatively affect the tensile modulus (332.2 +/- 31.3 MPa and 328.5 +/- 34.7 MPa for unmodified and surface-modified PCL, respectively) and strength (15.1 +/- 1.3 MPa and 14.8 +/- 1.5 MPa as assessed before and after the surface modification, respectively), as well as the mechanical behaviour evaluated through small punch test. XPS and enzyme-linked lectin assay (ELLA) demonstrate the presence, and also the correct exposition of the saccharidic epitope on PCL substrates. The introduction of carbohydrate moieties on the PCL surfaces clearly enhances the hydrophilicity of the substrate, as the water contact angle decreases from 82.1 +/- 5.8 degrees to 62.1 +/- 4.2 degrees. Furthermore, preliminary biological analysis shows human mesenchymal stem cell viability over time and an improvement of cell adhesion and spreading. (C) 2014

Chitosan is a marine-origin polysaccharide obtained from the deacetylation of chitin, the main component of crustaceans’ exoskeleton, and the second most abundant in nature. Although this biopolymer has received limited attention for several decades right after its discovery, since the new millennium chitosan has emerged owing to its physicochemical, structural and biological properties, multifunctionalities and applications in several sectors. This review aims at providing an overview of chitosan properties, chemical functionalization, and the innovative biomaterials obtained thereof. Firstly, the chemical functionalization of chitosan backbone in the amino and hydroxyl groups will be addressed. Then, the review will focus on the bottom-up strategies to process a wide array of chitosan-based biomaterials. In particular, the preparation of chitosan-based hydrogels, organic–inorganic hybrids, layer-by-layer assemblies, (bio)inks and their use in the biomedical field will be covered aiming to elucidate and inspire the community to keep on exploring the unique features and properties imparted by chitosan to develop advanced biomedical devices. Given the wide body of literature that has appeared in past years, this review is far from being exhaustive. Selected works in the last 10 years will be considered.

The synthesis of new dendrons and their immobilization on collagen patches via thiol − ene photoclick reaction, followed by chemoselective alkoxyamino − carbonyl conjugation to carbohydrates is presented. XPS, FTIR, and ELLA assays con fi rmed the e ff ectiveness of the collagen multivalent neoglycosylation

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 mono-saccharides 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. Preliminary biological evaluation in osteoarthritic models is reported. The proposed methodology can be extended to any thiolated surface for the development of smart biomaterials for innovative approaches in regenerative medicine.

A new approach for tethering of bioactive molecules via arginine is proposed and validated on collagen 2D matrices. The method involves the introduction of a methyl ketone on arginine side-chains, followed by reaction with model alkoxyamino derivatives. This journal is © the Partner Organisations 2014.

Hydrogels are useful platforms as three-dimensional (3D) scaffolds for cell culture, drug-release systems, and regenerative medicine applications. Here, we propose a novel chemical cross-linking approach by the use of 3,4-diethoxy-3-cyclobutene-1,2-dione or diethyl squarate for the preparation of 5 and 10% w/v gelatin-based hydrogels. Hydrogels showed good swelling properties, and the 5% gelatin-based hydrogel proved suitable as a 3D cell culture scaffold for the chondrocyte cell line C28/I2. In addition, diffusion properties of different sized molecules inside the hydrogel were determined.

Binary nano-biocomposite 3D scaffolds of cellulose nanocrystals (CNCs) - gelatin were fabricated without the use of chemical cross-linking additives. Controlled oxidative treatment allowed the introduction of carboxyl or carbonyl functionalities on the surface of CNCs that were responsible for the cross-linking of gelatin polymers. The obtained composites were characterized for their physico-chemical properties, and their biocompatibility towards different cell cultures was eval-uated through MTT and LDH assays, cellular adhesion and proliferation experiments. Gelatin composites reinforced with carbonyl-modified CNCs showed the most performing swell-ing/degradation profile and the most promising adhesion and proliferation properties towards cell lines, suggesting their potential application in the field of tissue engineering