Protos Research Institute

Trieste, Italy

Protos Research Institute

Trieste, Italy
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Grassi M.,University of Trieste | Feruglio L.,University of Trieste | Feruglio L.,Protos Research Institute | Giuliani G.,University of Siena | And 3 more authors.
International Journal of Pharmaceutics | Year: 2010

Poly[monomethylnona(ethylene glycol) 1-methylene-3-(4-methylphenyl)-1. H-indene-2-carboxylate] (poly-1b) a new polymer based on a PEG-functionalized benzofulvene macromonomer have been investigated as hydrogel-based material for complexation and release of immunoglobulin (IgG) at physiological mimicking conditions.The polymer ability to complex human IgG has been studied by preparing copolymer/protein complexes obtained by spontaneous protein interactions onto polymer hydrogel aggregates, and the protein release rate has been evaluated at physiological conditions. SEM analysis was used to visualize the copolymer/IgG aggregates and its microstructured deposition. Moreover, rheological studies performed at 37°C allowed determining hydrogel mechanical properties. On the basis of these information and NMR transverse relaxation measurements, the estimation of hydrogel mesh size distribution was possible.Finally, biological studies performed with poly-1b aqueous dispersions showed no cytotoxic effect on MCF-7 cell line, suggesting potential biocompatibility features for this polymer and making this new polymer a good potential candidate for the production of drug delivery systems. © 2010 Elsevier B.V.

Subramanian N.,Dravidian University | Sundaraganesan N.,Annamalai University | Sudha S.,Annamalai University | Aroulmoji V.,PROTOS Research Institute | And 2 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

The Fourier Transform Infrared spectrum of (S)-4 ethyl-4-hydroxy-1H-pyrano [3′,4′:6,7]-indolizino-[1,2-b-quinoline-3,14-(4H,12H)-dione] [camptothecin] was recorded in the region 4000-400 cm-1. The Fourier Transform Raman spectrum of camptothecin (CPT) was also recorded in the region 3500-50 cm-1. Quantum chemical calculations of geometrical structural parameters and vibrational frequencies of CPT were carried out by MP2/6-31G(d,p) and density functional theory DFT/B3LYP/6-311++G(d,p) methods. The assignment of each normal mode has been made using the observed and calculated frequencies, their IR and Raman intensities. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. Most of the computed frequencies were found to be in good agreement with the experimental observations. The isotropic chemical shifts computed by 13C and 1H NMR analysis also show good agreement with experimental observations. Comparison of calculated spectra with the experimental spectra provides important information about the ability of computational method to describe the vibrational modes of large sized organic molecule. © 2010 Elsevier B.V. All rights reserved.

Perin D.,Protos Research Institute | Murano E.,Protos Research Institute | Murano E.,Nealys Srl
Natural Product Communications | Year: 2017

Starch is the main source of carbohydrates in human diet. It is widely used in food processing and non-food industrial applications. The effects on starch digestion and absorption in humans are reviewed in relation to the starch composition, sources, plant genetic variation, food processing and cooking. The impact of food industrial processing and starch modification on the digestibility of starch containing foods and on gut microbiota are discussed. Considering that the resistant starch (RS) fraction escaped from the small intestine is fermented in large intestine, all the variables that influence starch digestibility and absorption must be taken into account when discussing about healthy properties of fibers. Future trends in food industries are aimed to increase the RS fraction in processed foods in order to improve nutritional quality as well as to clarify the influence of RS3 and RS4 on gut microbiota.

Murano E.,PROTOS Research Institute | Murano E.,NEALYS srl | Perin D.,PROTOS Research Institute | Khan R.,PROTOS Research Institute | And 2 more authors.
Natural Product Communications | Year: 2011

Hyaluronan (hyaluronic acid) is a naturally occurring polysaccharide of a linear repeating disaccharide unit consisting of β-(1→4)-linked D-glucopyranuronic acid and β-(1→3)-linked 2-acetamido-2-deoxy-D- glucopyranose, which is present in extracellular matrices, the synovial fluid of joints, and scaffolding that comprises cartilage. In its mechanism of synthesis, its size, and its physico-chemical properties, hyaluronan is unique amongst other glycosaminoglycans. The network-forming, viscoelastic and its charge characteristics are important to many biochemical properties of living tissues. It is an important pericellular and cell surface constituent; its interaction with other macromolecules such as proteins, participates in regulating cell behavior during numerous morphogenic, restorative, and pathological processes in the body. The knowledge of HA in diseases such as various forms of cancers, arthritis and osteoporosis has led to new impetus in research and development in the preparation of biomaterials for surgical implants and drug conjugates for targeted delivery. A concise and focused review on hyaluronan is timely. This review will cover the following important aspects of hyaluronan: (i) biological functions and synthesis in nature; (ii) current industrial production and potential biosynthetic processes of hyaluronan; (iii) chemical modifications of hyaluronan leading to products of commercial significance; and (iv) and the global market position and manufacturers of hyaluronan.

Marega A.R.,University of Namur | Bergamin M.,Protos Research Institute | Aroulmoji V.,Protos Research Institute | Dinon F.,Cimteclab Spa | And 2 more authors.
European Journal of Organic Chemistry | Year: 2011

Carbon nanotube (CNTs) derivatives are nowadays under thorough investigation as biomedically interesting materials. In this paper we describe a method for the preparation of water-soluble CNTs by condensation of the carboxylic groups introduced onto the carbon framework and the primary amine moieties inserted in the naturally occurring biopolymer hyaluronan (HA). The covalent conjugation between CNTs and HA should merge the biocompatibility and further processability of the HA chains with the well-known cellular penetration properties of the CNT derivatives to produce novel drug delivery platforms. In fact, thanks to the primary amino groups introduced in the HA chains, HA-CNT derivatives can be further covalently modified with model drugs like ibuprofen and methotrexate. We describe also the monitoring of all the CNT derivatization steps by diffusion-ordered NMR spectroscopy (DOSY), a technique that allows fast and reliable characterization of these novel derivatives. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ayyappan S.,Government College of Technology, Coimbatore | Ayyappan S.,Bharathar University | Sundaraganesan N.,Annamalai University | Aroulmoji V.,PROTOS Research Institute | And 2 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2010

The FT-IR and FT-Raman spectral studies of the Methotrexate (MTX) were carried out. The equilibrium geometry, various bonding features and harmonic vibrational frequencies of MTX have been investigated with the help of B3LYP density functional theory (DFT) using 6-31G(d) as basis set. Detailed analysis of the vibrational spectra has been made with the aid of theoretically predicted vibrational frequencies. The vibrational analysis confirms the differently acting ring modes, steric repulsion, conjugation and back-donation. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) results complement with the experimental findings. The calculated HOMO and LUMO energies show that charge transfer occur within the molecule. Good correlations between the experimental 1H and 13C NMR chemical shifts in DMSO solution and calculated GIAO shielding tensors were found. © 2010 Elsevier B.V.

Marega R.,University of Trieste | Aroulmoji V.,Protos Research Institute | Bergamin M.,Protos Research Institute | Bergamin M.,EURAND S.p.A | And 6 more authors.
ACS Nano | Year: 2010

Functionalized carbon nanotube (CNT) derivatives are currently under thorough investigation in different biomedical investigations. In this field of research, the composition of sample either in terms of covalently attached or physisorbed moieties can greatly affect the observed results and hamper the comparison between different studies. Therefore, the availability of a fast and reliable analytical technique to assess both the type of interaction (covalent vs noncovalent) and the composition of CNT conjugates is of great importance. Here we describe that the two-dimensional diffusion-ordered (DOSY) NMR spectroscopy is extremely useful to discriminate between conjugated and unconjugated polyethylene glycol groups in samples obtained by condensation with oxidized single-walled carbon nanotubes (SWNTs). This fast and nondestructive technique allows us to follow the removal of unconjugated polyethylene glycol chains during the purification. In particular, DOSY analysis reveal that about 1/3 (wt %) of the polyethylene glycol used for the condensation remained physisorbed to functionalized SWNTs after dialysis. Complete elimination of physisorbed polyethylene glycol was achieved using diafiltration. © 2010 American Chemical Society.

Aroulmoji V.,Center Europol Agro | Aroulmoji V.,PROTOS Research Institute | Mathlouthi M.,Center Europol Agro | Feruglio L.,University of Trieste | And 3 more authors.
Food Chemistry | Year: 2012

Proton NMR relaxation rates (R 1 and R 2) were measured in aqueous solutions of sucrose, d-glucose and d-fructose with increasing concentration. The measurements were carried out using Bruker PC 20 NMR Process Analyzer. Inversion recovery and CPMG pulse sequences are used for the measurement of relaxation rates. Results show that the values of relaxation rate increase as the concentration of the sugar is increased. The relaxation rate appears to be higher for sucrose solutions as compared to glucose or d-fructose solutions. These results were discussed on the basis of molecular association between sugar and water molecules through hydrogen bonding. The water self diffusion coefficient was measured in these sugar solutions by using pulse field gradient NMR method. As expected, the water self-diffusion coefficient was reduced with increased sugar concentrations. The results of translational mobility exhibited a higher mobility for fructose than glucose or sucrose in aqueous solutions. The dependence of R 2 on the inter-pulse delay of the CPMG sequence gives information on the proton exchange mechanism involved. The mechanism of exchange was studied using R 2 with increasing inter pulse delay of 0.05-2.0 ms in aqueous solutions of 10%, 20% and 35% (w/v) of the above sugar solutions. From the plots of relaxation rates (R 2) versus the 90°-180°pulse spacing it was possible to calculate the proton exchange rate (k b) of the different sugar solutions. Relaxation rates show characteristic variations with CPMG pulse spacing which can be interpreted on the basis of chemical exchange between solute and solvent molecules. The experimental results namely relaxation rates and CPMG pulse spacing data show the importance of water interactions with sweet molecules and this can lead to a better understanding of the effect of hydration water in taste chemoreception. © 2011 Elsevier Ltd. All rights reserved.

Pescosolido L.,University of Rome La Sapienza | Pescosolido L.,University Utrecht | Feruglio L.,PROTOS Research Institute | Feruglio L.,University of Trieste | And 8 more authors.
Soft Matter | Year: 2012

The importance of Interpenetrating Polymer Networks (IPNs) in biomedical and pharmaceutical fields is continuously growing because of their mechanical and drug carrier tailoring opportunities. This paper deals with the physico-chemical characterization of an IPN hydrogel based on calcium-alginate and a dextran methacrylate derivative. The attention is focused on the determination of IPN mesh size distribution. For this purpose, two different approaches were applied, namely using a combination of rheological and low field NMR characterization, and cryoporosimetry. Appropriate mathematical models were developed for the interpretation of the experimental data. Both approaches led to a mono-modal mesh size distribution spanning the same size range but characterized by different mean values (25 nm, Rheo-NMR; 44 nm, cryoporosimetry). This is probably due to mesh widening upon water freezing. Moreover, release experiments of a model protein - myoglobin - from the IPN were performed and the obtained data were combined with the results of the two above mentioned approaches. Release tests yielded an estimation of the mean mesh size that is closer to that obtained according to the rheology-NMR approach than that resulting from cryoporosimetry measurements. © 2012 The Royal Society of Chemistry.

Anbarasan P.M.,Periyar University | Senthil Kumar P.,Periyar University | Vasudevan K.,Periyar University | Moorthy Babu S.,Anna University | Aroulmoji V.,PROTOS Research Institute
Acta Physica Polonica A | Year: 2011

The geometries, electronic structures, polarizabilities, and hyperpolarizabilities of organic dye sensitizers 3,4-pyridinedicarbonitrile, 3-aminophthalonitrile, 4-aminophthalonitrile and 4-methylphthalonitrile were studied based on density functional theory using the hybrid functional B3LYP. Ultraviolet-visible spectra were investigated by time dependent density functional theory. The features of electronic absorption spectra in the visible and near-UV regions were assigned based on time dependent density functional theory calculations. The absorption bands are assigned to π → π* transitions. Calculated results suggest that the three lowest energy excited states of 3,4-pyridinedicarbonitrile, 3- aminophthalonitrile, 4-aminophthalonitrile and 4-methylphthalonitrile are due to photoinduced electron transfer processes. The interfacial electron transfer between semiconductor TiO2 electrode and dye sensitizers 3,4-pyridinedicarbonitrile, 3-aminophthalonitrile, 4-aminophthalonitrile and 4-methylphthalonitrile is due to an electron injection process from excited dyes to the semiconductor's conduction band. The role of amide and methyl groups in phthalonitrile in geometries, electronic structures, and spectral properties were analyzed in a comparative study of 3,4-pyridinedicarbonitrile, 3-aminophthalonitrile, 4-aminophthalonitrile and 4-methylphthalonitrile for the improvement of dye sensitized solar cells.

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