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Giuseppe Ciccarella
Ruolo
Professore Associato
Organizzazione
Università del Salento
Dipartimento
Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali
Area Scientifica
Area 03 - Scienze chimiche
Settore Scientifico Disciplinare
CHIM/07 - Fondamenti Chimici delle Tecnologie
Settore ERC 1° livello
PE - Physical sciences and engineering
Settore ERC 2° livello
PE5 Synthetic Chemistry and Materials: Materials synthesis, structure-properties relations, functional and advanced materials, molecular architecture, organic chemistry
Settore ERC 3° livello
PE5_6 New materials: oxides, alloys, composite, organicinorganic hybrid, nanoparticles
A "heart-cut" two-dimensional achiral-chiral liquid chromatography triple-quadrupole mass spectrometry method (LC-LC-MS/MS) was developed and coupled to in vivo cerebral microdialysis to evaluate the brain response to the chiral compound (±)-7-chloro-5-(3-furanyl)-3-methyl-3,4-dihydro-2H-1,2,4-benzothiadiazine-1,1-dioxide ((±)-1), a potent positive allosteric modulator (PAM) of AMPA receptor. The method was successfully employed to evaluate also its stereoselective metabolism and in vitro biological activity. In particular, the LC achiral method developed, employs a pentafluorinated silica based column (Discovery HS-F5) to separate dopamine, acetylcholine, serotonin, (±)-1 and its two hepatic metabolites. In the "heart-cut" two-dimension achiral-chiral configuration, (±)-1 and (±)-1-d4 eluted from the achiral column (1st dimension), were transferred to a polysaccharide-based chiral column (2nd dimension, Chiralcel OD-RH) by using an automatic six-port valve. Single enantiomers of (±)-1 were separated and detected using electrospray positive ionization mode and quantified in selected reaction monitoring mode. The method was validated and showed good performance in terms of linearity, accuracy and precision. The new method employed showed several possible applications in the evaluation of: (a) brain response to neuroactive compounds by measuring variations in the brain extracellular levels of selected neurotransmitters and other biomarkers; (b) blood brain barrier penetration of drug candidates by measuring the free concentration of the drug in selected brain areas; (c) the presence of drug metabolites in the brain extracellular fluid that could prove very useful during drug discovery; (d) a possible stereoselective metabolization or blood brain barrier stereoselective crossing of chiral drugs. Finally, compared to the methods reported in the literature, this technique avoids the necessity of euthanizing an animal at each time point to measure drug concentration in whole brain tissue and provides continuous monitoring of extracellular concentrations of single chiral drug enantiomers along with its metabolites in specific brain regions at each selected time point for a desired period by using a single animal.
Three new metal-free organic dyes with the [1]benzothieno[3,2-b]benzothiophene (BTBT) π-bridge, having the structure donor-π-acceptor (D-π-A) and labeled as 19, 20 and 21, have been designed and synthesized for application in dye-sensitized solar cells (DSSC). Once the design of the π-acceptor block was fixed, containing the BTBT as the π-bridge and the cyanoacrylic group as the electron acceptor and anchoring unit, we selected three donor units with different electron-donor capacity, in order to assemble new chromophores with high molar extinction coefficients (ε), whose absorption features well reflect the good performance of the final DSSC devices. Starting with the 19 dye, which shows a molar extinction coefficient ε of over 14,000 M(-1) cm(-1) and takes into account the absorption maximun at the longer wavelength, the substitution of the BFT donor unit with the BFA yields a great enhancement of absorptivity (molar extinction coefficient ε > 42,000 M(-1) cm(-1)), until reaching the higher value (ε > 69,000 M(-1) cm(-1)) with the BFPhz donor unit. The good general photovoltaic performances obtained with the three dyes highlight the suitable properties of electron-transport of the BTBT as the π-bridge in organic chromophore for DSSC, making this very cheap and easy to synthesize molecule particularly attractive for efficient and low-cost photovoltaic devices.
5-Arylbenzothiadiazine type compounds acting as positive allosteric modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-PAMs) have received particular attention in the past decade for their nootropic activity and lack of the excitotoxic side effects of direct agonists. Recently, our research group has published the synthesis and biological activity of 7-chloro-5-(3-furanyl)-3-methyl-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (1), one of the most active benzothiadiazine-derived AMPA-PAMs in vitro to date. However, 1 exists as two stereolabile enantiomers, which rapidly racemize in physiological conditions, and only one isomer is responsible for the pharmacological activity. In the present work, experiments carried out with rat liver microsomes show that 1 is converted by hepatic cytochrome P450 to the corresponding unsaturated derivative 2 and to the corresponding pharmacologically inactive benzenesulfonamide 3. Surprisingly, patch-clamp experiments reveal that 2 displays an activity comparable to that of the parent compound. Molecular modeling studies were performed to rationalize these results. Furthermore, mice cerebral microdialysis studies suggest that 2 is able to cross the blood-brain barrier and increases acetylcholine and serotonin levels in the hippocampus. The experimental data disclose that the achiral hepatic metabolite 2 possesses the same pharmacological activity of its parent compound 1 but with an enhanced chemical and stereochemical stability, as well as an improved pharmacokinetic profile compared with 1.
Iron oxide nanoparticles are the most used magnetic nanoparticles in biomedical and biotechnological field because of their nontoxicity respect to the other metals. The investigation of iron oxide nanoparticles behaviour in aqueous environment is important for the biological applications in terms of polydispersity, mobility, cellular uptake and response to the external magnetic field. Iron oxide nanoparticles tend to agglomerate in aqueous solutions; thus, the stabilisation and aggregation could be modified tuning the colloids physical proprieties. Surfactants or polymers are often used to avoid agglomeration and increase nanoparticles stability. We have modelled and synthesised iron oxide nanoparticles through a co-precipitation method, in order to study the influence of surfactants and coatings on the aggregation state. Thus, we compared experimental results to simulation model data. The change of Z-potential and the clusters size were determined by Dynamic Light Scattering. We developed a suitable numerical model to predict the flocculation. The effects of Volume Mean Diameter and fractal dimension were explored in the model. We obtained the trend of these parameters tuning the Z-potential. These curves matched with the experimental results and confirmed the goodness of the model. Subsequently, we exploited the model to study the influence of nanoparticles aggregation and stability by Z-potential and external magnetic field. The highest Z-potential is reached up with a small external magnetic influence, a small aggregation and then a high suspension stability. Thus, we obtained a predictive model of Iron oxide nanoparticles flocculation that will be exploited for the nanoparticles engineering and experimental setup of bioassays.
The possibility to ignite the single wall carbon nanotubes (SWCNTs) containing impurities of iron in atmosphere once exposed to the radiation of a flash camera was observed for the first time in 2002. Afterwards, it was proposed to exploit this property in order to use nanostructured materials as ignition agents for fuel mixtures. Finally, in 2011 it was shown that SWCNTs can be effectively used as ignition source for an air/ethylene mixture filling a constant volume combustion chamber; the observed combustion presented the characteristics of a homogeneous-like combustion. In this paper a system for the ignition of an air/methane mixture is proposed, based on the exposition of multi wall carbon nanotubes (MWCNTs) to a low consumption flash camera. Namely, several experiments have been run in which 20 mg of MWCNTs, containing 75% in weight of ferrocene, have been added to an air/methane fuel mixture inside a constant volume combustion chamber. The mixture has been heated up to 373 K and the onset pressure was set equal to 3 bar. The experiments have been run varying the equivalence ratio in the range 1 - 2. The combustion process so realized has been compared to that obtained igniting the mixture with a traditional spark as in spark ignition engines. The comparison has been based on chamber pressure measurement as well as combustion process images, both sampled at a frequency equal to 2,5 kHz for an overall duration of 1.8 s. Results confirm that the ignition triggered with MWCNTs leads to a homogeneous-like combustion, without observing a well-defined flame front propagation. The contrary is observed, as expected, with the spark assisted ignition. Moreover, dynamic pressure measurements show that, compared to spark assisted ignition, the MWCNTs photo-ignition determines a more rapid pressure gradient and a higher peak pressure which corresponds to a higher energy release rate.
Complexes of the type [PtCl(N-N)(eta(1)-CH2CH2OR)], N-N = diimine ligand, R = alkyl, were generally considered to be indefinitely stable, both in solution and in the solid state. Unexpectedly we found that complexes of the type [PtCl(Me(2)phen)(eta(1)-CH2CH2OR)], Me(2)phen 2,9-dimethyl-1,10-phenatroline, R = alkyl, undergo spontaneous decomposition, to give the corresponding vinyl-ether, CH2 = CHOR. Decomposition pathway studies suggest a pseudo-Wacker type mechanism (beta H- shift process) activated by sterical hindrance in the Pt(II) coordination plane, due to the Me(2)phen ligand sterically induced distortions in the Pt(II) coordination plane. A new useful synthetic pathway to access valuable and low toxic alkyl-vinyl-ethers is here reported.
Almost all Iridium(III) complexes employed both as dopants in PhOLEDs and as pharmaceuticals and fluorescence bioprobes are racemic mixtures. In this study the single enantiomers of the most stable diastereomeric form fac-trans-N-N, bis[2-(4,6-difluorophenyl)pyridinato-C(2),N](picolinato)iridium(III) (FIrpic) were separated and analysed. The data obtained showed that the complex can be separated into stable optically active Λ and Δ isomers employing cellulose based chiral stationary phase both in normal and polar phase mode. Their chirality was confirmed and their absolute configuration assigned employing several methods (DFT and TDDFT calculations, CD and VCD). The CPL spectroscopy of the isolated enantiomers of FIrpic was also recorded due to its possible value in the OLEDs field. The chromatographic method was applied for a semipreparative purpose demonstrating that polar organic solvent chromatography (POSC) could be used to avoid the low-solubility issues associated with these Iridium(III) complexes. Finally, the chemical and stereochemical stability of the single isomers was evaluated under thermal stress by liquid chromatography coupled to high-resolution mass spectrometry (LC-QTOF) on both chiral and achiral columns. No racemization and/or isomerization was observed; however, the dissociation of the ancillary ligand was demonstrated employing LC-QTOF.
In this work, the effects due to the addition of nanoparticles in polyurethane foams on thermo-physical and mechanical properties have been evaluated. Two types of nanoparticles were used, acetic and oleic-modified titania nanocrystals TiO2. The nanoparticles were first dispersed in a polyol component via the use of sonication; then, the doped polyol was mixed with isocyanate. The different characterization techniques describe the state of the dispersion of fillers in foam. The effects of these additions in foam were evaluated according to UNI EN 826-UNI EN 12087- UNI EN 13165, in terms of thermo-physical and mechanical properties, i.e., diffusivity, conductivity, compressive strength and water uptake. The microstructure of the foam was analysed using scanning electron microscopy (SEM). The foam obtained with nanoadditives presented improved mechanical characteristics compared to neat foam, presumably due to the different shape of the nanoparticles. The addition of nanoparticles favoured the formation of nucleation centres; this effect was likely due to the size, shape and distribution of particles and due to their surface treatment.
In this study we evaluated an efficient microwave-solvothermal method to synthesize effective visible-light photocatalists based on the use of anatase TiO2 nanorods. The nanocrystals were obtained by hydrolysis of titanium tetraisopropoxide (TTIP) in the presence of benzyl alcohol at 210 °C. The method was effective and produced TiO2 nanocrystals in the anatase phase with a rapid kinetics of crystallization. A significant size control was obtained tuning the TTIP to oleic acid molar ratio. High volumetric yield and reduced energy costs were achieved. All synthesized TiO2 nanocrystals showed a high photoactivity in comparison with commercial P25 titania, as they could degrade faster and completely Rhodamine B dye in solution under visible-light irradiation. The nanocrystals were characterized in detail by X-ray diffraction, low- and high-resolution transmission electron microscopy, microRaman and FT-IR spectroscopy. A distorted anatase structure due to oxygen vacancies was identified as being at the origin of the introduction of new energy levels into the anatase band gap, which probably promoted the visible-light photoactivity.
Three fluorenone-derived two-photon fluorescent probes (TK) targeting the lysosomes (TK-Lyso) and mitochondria (TK-Mito1 and TK-Mito2) were synthesized by introducing different diphenylamine moieties into the fluorenone core. The TK dyes showed high biocompatibility and long-term retention, low cytotoxicity, large Stokes shift and good fluorescence quantum yield. The results of the present work disclose a class of organic dyes with potential wide applications as specific and efficient probes for lysosomes and mitochondria in the study of various biological processes.
High-yield, rapid and facile synthesis of elongated pure anatase titania nanoparticles has been achieved through a nonaqueous microwave-based approach. The residual organics onto nanoparticles surfaces were completely removed through a new treatment under ozone flow, at room temperature in air. Such an ozone cleaning method revealed an effective inexpensive dry process of removing organic contaminants from nanoparticles surfaces. The TiO2 elongated nanoparticles having a length of 13.8 ± 5.5 nm and a diameter of 9.0 ±1.2 nm were characterized by powder X-Ray diffraction, transmission electron microscopy, selected area diffraction, BET surface area analyzer and FT‑IR spectroscopy. Photocatalytic evaluation demonstrated that the as-synthesized ozone-cleaned TiO2 nanoparticles and TiO2 nanoparticles loaded with platinum possess excellent Rhodamine B performance with respect to both commercial spherical nanotitania P25 and P25 loaded with platinum. This could be attributed to the anatase phase purity, small size, large specific surface area and clean surfaces of the prepared nanoparticles.
High-yield, rapid and facile synthesis of elongated pure anatase titania nanoparticles has been achieved through a nonaqueous microwave-based approach. The residual organics onto nanoparticles surfaces were completely removed through a new treatment under ozone flow, at room temperature in air. Such an ozone cleaning method revealed an effective inexpensive dry process of removing organic contaminants from nanoparticles surfaces. The TiO2 elongated nanoparticles having a length of 13.8 +/- 5.5 nm and a diameter of 9.0 +/- 1.2 nm were characterized by powder X-Ray diffraction, transmission electron microscopy, selected area diffraction, BET surface area analyzer and FT-IR spectroscopy. Photocatalytic evaluation demonstrated that the as-synthesized ozone-cleaned TiO2 nanoparticles and TiO2 nanoparticles loaded with platinum possess excellent Rhodamine B performance with respect to both commercial spherical nanotitania P25 and P25 loaded with platinum. This could be attributed to the anatase phase purity, small size, large specific surface area and clean surfaces of the prepared nanoparticles.
In this work, we investigate the optical and structural properties of the well-known triplet emitter bis(4',6'-difluorophenylpyridinato)-iridium(III) picolinate (FIrpic), showing that its ability to pack in two different ordered crystal structures promotes attractive photophysical properties that are useful for solid-state lighting applications. This approach allows the detrimental effects of the nonradiative pathways on the luminescence performance in highly concentrated organic active materials to be weakened. The remarkable electro-optical behavior of sky-blue phosphorescent organic light-emitting diodes incorporating crystal domains of FIrpic, dispersed into an appropriate matrix as an active layer, has also been reported as well as the X-ray diffraction, nuclear magnetic resonance, electro-ionization mass spectrometry, and scanning electron microscopy analyses of the crystalline samples. We consider this result as a crucial starting point for further research aimed at the use of a crystal triplet emitter in optoelectronic devices to overcome the long-standing issue of luminescence self-quenching.
Pectin is a natural biopolymer that forms, in the presence of divalent cations, ionic-bound gels typifying a large class of biological gels stabilized by non-covalent cross-links. We investigate and compare the kinetics of formation and aging of pectin gels obtained either through external gelation via perfusion of free Ca2+ ions, or by internal gelation due to the supply of the same ions from the dissolution of CaCO3 nanoparticles. The microscopic dynamics obtained with photon correlation imaging, a novel optical technique that allows obtaining the microscopic dynamics of the sample while retaining the spatial resolution of imaging techniques, is contrasted with macroscopic rheological measurements at constant strain. Pectin gelation is found to display peculiar two-stage kinetics, highlighted by non-monotonic growth in time of both microscopic correlations and gel mechanical strength. These results are compared to those found for alginate, another biopolymer extensively used in food formulation.
Abstract Hybrid inorganic/organic core/shell nanoparticles were prepared through a two step synthesis procedure. In the first step, pure anatase TiO2 nanoparticles were synthesized though a rapid microwave assisted non-aqueous route. Then, the obtained titania nanoparticles were coated with polyvinyl alcohol (PVA) using a simple solution method followed by relatively low temperature treatment. The PVA-coated titania nanoparticles samples were prepared at different TiO2-PVA weight ratio and they were characterized using X-Ray diffraction, transmission electron microscopy, infrared spectroscopy and Brunauer-Emmett-Teller (BET) analysis. Photocatalytic performance was also evaluated for all samples and the results indicated that TiO2:PVA weight ratio was a key factor to obtain an improvement of the photocatalytic activity with respect to bare TiO2 nanoparticles, since {PVA} concentration influenced the surface area and the aggregation of nanoparticles and the thickness of the coating layer. This inexpensive system provides a simple, quick and effective approach which allows to obtain core/shell hybrid nanostructures.
This study reports oil the first monodispersed molecular materials embodying the dibenzothiophene-5,5-dioxide core for the achievement of blue electroluminescence. The core has been functionalised in its 2.8- or 3,7-positions with dimethyl-fluorene (2,8-DBTOF and 3,7-DBTOF) or methyl-carbazole (2,8-DBTOC and 3,7-DBTOC) groups. The obtained compounds were characterised by H-1 and C-13 NMR, APCI-MS, thermal analysis (TGA and DSQ and cyclic voltammetry. Their optical and photophysical properties were investigated by UV and PL measurements as well as by time-dependent density-functional theory calculations. The materials were successfully employed as active layers ill blue to purplish blue p-i-n OLED devices. that reached, in the case of 3,7-DBTOC, performances as high as 11 422 cd m(-2) and 3.25 cd A(-1).
Novel triphenylamine (TPA)-based organic dyes were synthesized and assessed for their performance in dye-sensitized solar cells (DSSCs). In the dyes considered the TPA group and the cyanoacetic acid have the role of electron-donor and -acceptor, respectively, whereas a thienyl-fluoro-phenyl-substituted was introduced as p-linker to improve the dye performance in DSSCs. Experimental characterizations empasize that the presence of electron withdrawing substituents in the linker close to the electron-acceptor moiety leads to a more efficient intramolecular photoinduced charge transfer. In fact, photovoltaic experiments reveal that the DSSCs based on the thienyl-o-fluoro-phenyl substituted dyes yield a better solar-energy-to-electricity conversion efficiency.
In this investigation, differently shaped and surface functionalized TiO2 anatase nanoparticles and human serum albumin (HSA) were selected to study proteinnanoparticles interaction both in a solution and on flat surfaces, thereby mimicking a medical device. Anatase nanocrystals were characterized by transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface analysis and dynamic light scattering (DLS). The proteinnanoparticles’ interactions and their eventual reversibility were studied by pH dependent ζ- potential measurements in different media: ultra-pure water, a phosphate buffer simulating physiological conditions and in a culture medium supplemented with foetal bovine serum. The protein corona masking effect was evidenced and the interaction HSA-nanocrystals resulted irreversible. The interaction HSA-silicon supported TiO2 nanocrystals films was studied by atomic force microscopy (AFM), and resulted driven by the substrate hydrophilicity degree plus was different for the diverse range of nanocrystals tested. Surface roughness measurements showed that on some of the nanocrystals, HSA were arranged in a more globular manner. A lower protein affinity was found for nanocrystals that had a smaller primary particle size, which may correspond to their higher biocompatibility. This nano-bio interface research aimed to study the HSA protein-TiO2 anatase nanocrystals under conditions similar to those for in vitro and in vivo toxicity analyses.
In the last few years, there has been a boost in the use of cannabis-based extracts for medicinal purposes, although their preparation procedure has not been standardized but rather decided by the individual pharmacists. The present work describes the development of a simple and rapid high performance liquid chromatography method with UV detection (HPLC-UV) for the qualitative and quantitative determination of the principal cannabinoids (CBD-A, CBD, CBN, THC and THC-A) that could be applied to all cannabis-based medicinal extracts (CMEs) and easily performed by a pharmacist. In order to evaluate the identity and purity of the analytes, a high-resolution mass spectrometry (HPLC-ESI-QTOF) analysis was also carried out. Full method validation has been performed in terms of specificity, selectivity, linearity, recovery, dilution integrity and thermal stability. Moreover, the influence of the solvent (ethyl alcohol and olive oil) was evaluated on cannabinoids degradation rate. An alternative extraction method has then been proposed in order to preserve cannabis monoterpene component in final CMEs.
Microfluidics based on the capillarity-induced filling of elastomeric channels by a suitable liquid or solution represents a useful route for realizing portable diagnostic devices designed without additional mechanical or electrical micropumps. In this study, an elastomeric mold made of poly(dimethylsiloxane) (PDMS), containing relief patterns placed in intimate contact with a silicon substrate, is utilized to create a continuous network of rectangular micro-channels for the motion of water fluid. The immobilization on activated PDMS surface of suitable functional molecules such as hydrophilic and hydrophobic fluorine-containing aminonaphthols, obtained through a straightforward and versatile synthetic procedure, allowed us to modulate PDMS surface properties depending on the structural characteristics of the employed derivative. In this context, the incorporation of fluorine groups is important for improving biocompatibility of the resulting device, providing surfaces that could be chemically and biologically inert as well as resistant to surface adhesion phenomena. The functionalization from liquid phase of PDMS replicas, involving a covalent derivatization via silanization reaction of the above mentioned compounds to an oxidized PDMS surface, resulted in a successful modification of microfluidic motion of water in rectangular capillaries, moreover contact angle values evidence also how wettability of PDMS films could be modulated, with the fluorinated aminonaphthols fuctionalized PDMS exhibiting higher contact angles. (C) 2009 Elsevier B.V. All rights reserved.
The possibility to ignite the Single Wall Carbon Nanotubes (SWCNTs) once exposed to the radiation of a flash camera, was observed for the first time in 2002. Subsequently, it was proposed to exploit this property in order to use nanostructured materials as ignition agents for fuel mixtures. Lastly, in 2011, it was shown that SWCNTs can be effectively used as ignition source for an air/ethylene mixture filling a constant volume combustion chamber; the observed combustion presented the characteristics of a homogeneous-like combustion. In the presented experimental activity, the potentiality of igniting an air/methane mixture by flashing Multi Wall Carbon Nanotubes (MWCNTs) has been exploited, and the results compared with those obtained igniting the mixture with a traditional spark plug. In detail, two types of tests have been carried out: the first, aiming at comparing the combustion process flashing a variable amount of nanoparticles introduced into the combustion chamber at fixed air/methane ratio; the second, at comparing the combustion process with the one obtained using a traditional engine spark plug, varying the air/methane ratio and at fixed amount of MWCNTs. During tests, the combustion process has been characterized measuring the pressure into the combustion chamber as well as acquiring images with a high-speed camera. The results confirm that the ignition triggered with MWCNTs leads to a faster combustion, without observing a well-defined flame front propagation, observed, as expected, with the spark assisted ignition. Moreover, dynamic pressure measurements show that the MWCNTs photo-ignition determines a more rapid pressure gradient and a higher heat release rate compared to spark assisted ignition.
Nanometer-sized poly(acrylic acid) (PAA) hydrogels were synthesized by emulsion polymerization of methyl acrylate and subsequent acidic hydrolysis. The nanohydrogel was characterized by spectroscopic methods (FTIR and H-1-NMR) and scanning probe techniques, and their pH-dependent swelling behavior was studied by dynamic light scattering. To determine the suitability of PAA nanogels as pH-sensitive carriers for biomedical applications, uptake and release of an oligothiophene fluorophore and its albumin conjugated from PAA nanogels were investigated as a function of pH by absorption and photoluminescence measurements. It was observed that uptake and release processes of both the oligothiophene and its conjugate could be controlled by changing the pH of the external solution. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 2808-2815, 2010
Carbohydrate polimeric microcapsules were assembled using a LbL approach onto a CaCO3 core. The microcapsules were used to delivery the anticancer drug cisplatin into HeLa and MCF-7 cancer cell lines. Drug encapsulation, measured by ICP spectroscopy, was around 50% of the charging solution. Fluorimetric measurements showed an efficient cellular uptake of polysacchardic microcapsules in both cell lines. The drug-loaded capsules demonstrated a better efficiency against cell viability than the free drug. Specifically, the amount of platinum reaching genomic DNA was measured, showing that encapsulation improves the nuclear delivery of the drug for both cell lines.
Chitosan nanoparticles (CS NPs) have been widely exploited for the delivery of various types of drugs due to their biocompatibility, availability, ease of functionalization and other advantages. Nevertheless, despite their wide use, their mechanism of action is not very clear and many aspects still need to be investigated in detail, with only a few studies having studied the behavior of this polymer. We prepared CS NPs encapsulating dopamine (DA) and studied the generation of reactive oxygen species (ROS) and the antioxidant effect of the neurotransmitter in detail. Encapsulation of the drug and its subsequent sustained release significantly reduced the oxidation rate in vitro, thus potentially exerting neuroprotective effects. ROS production in SH-SY5Y cells was investigated through a H2O2 assay, while a deeper study of the enzymatic activity allowed us to determine the significant contribution of both GPx and SOD enzymes in preventing oxidative stress.
Three novel organic dyes, coded TK1, TK2 and TK3, incorporating two donor moieties, cyanoacrylic acid as an acceptor/anchoring group, the dibenzofulvene core and an oligothiophene spacer in a 2D-π-A system, were designed, synthesized, and successfully utilized in dye-sensitized solar cells. The dye TK3, containing two thiophene rings as spacers, shows an IPCE action spectrum with a high plateau from 390 nm to 600 nm, increased open-circuit photovoltage by 40 mV and short-circuit photocurrent by 7.03 mA cm-1, with respect to TK1. Using CDCA as the co-adsorbent material, the Jsc of TK3 was increased to 14.98 mA cm-1 and a strong enhancement in the overall conversion efficiency (7.45%) was realized by TK3 compared to TK1 (1.08%), in liquid electrolyte-based DSSCs.
A simple synthesis was applied and tested for the preparation of boron-doped titanium dioxide [TiO2(B)] nanocrystals using titanium tetraisopropoxide (TTIP) together with boric acid (H3BO3) and benzyl alcohol as reaction solvent. Changes in the TTIP/H3BO3 molar ratio allowed a scalable synthetic protocol with a significant B-dopant control. In particular, this approach does not need surfactants or a final calcination step. X-ray diffractometry (XRD), low- and high-resolution transmission electron microscopy (TEM and HRTEM), and micro Raman spectroscopy revealed that the TiO2 nanocrystals produced have diameters up to about 10 nm and are mainly of the anatase phase but that a brookite phase was progressively formed with increased dopant level. The amount of boron was measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES), and the presence of boron inside the crystals was determined by 11B cross-polarized magic-angle spinning nuclear magnetic resonance (11B CP-MAS NMR) spectroscopy. X-ray photoelectron spectroscopy (XPS) revealed the presence of boron on the nanocrystal surfaces, confirming the trend in the dopant concentration already observed with ICP-AES elemental analysis. Microphotoluminescence studies indicated the formation of three different typical luminescent defect states in correlation with the amount of added boron in the titania. UV/Vis absorption spectra showed a boron-dependent redshift of the absorption edge.
We present a novel, facile, and cost-effective method to prepare highly transparent mesoporous films made by anatase TiO2 nanorods that have been synthesized by a single-step solvothermal process. Such nanorods have been conveniently used as prepared-without completely removing the residual organics-to obtain suitable screen-printable paste by means of the use of proper polymeric binders. This method has been successfully implemented to fabricate highly efficient nanorod-based photoelectrodes for dye-sensitized solar cells. They showed an increment of the overall quantum conversion efficiency comprised between 34% and 58% with respect to cells based oil commercial P25 titanium dioxide nanoparticles. In particular, a maximum photocurrent density and solar conversion efficiency of 16.9 mA/cm(2) and 7.9% have been obtained, respectively.
Novel Donor-pi-Acceptor triphenylamine-based dyes were synthesized and characterized with regard to their photophysical and photoelectrochemical properties by introducing the ethynyl-2-thienyl moiety as spacer (YS-1). The modification of the donor triphenylamine, performed by intodroducing two p-methoxy groups gave the YS-2 dye. Experimental results showed that the UV-Vis absorption spectra changed exhibiting the increasing of the molar extinction coefficient as well as the red-shift in dichloromethane solution. The maximum power conversion efficiency under standard global AM 1.5 illumination for YS-1 was 4.1% rising to 5.3% when the cell was sensitized with YS-2. The interpretation of the improvement and the discussion of the experimental results were corroborated by Time-Dependent Density-Functional Theory calculations, carried out for the photosensitizers in vacuo and in solution. In particular, the effects on the spectroscopic properties of the dyes due to the presence of the solvent and to the common deprotonation of the carboxylic unit in polar solvents have been investigated.
The efficient internalization of TGF-beta inhibitor-loaded polyelectrolyte capsules and particles is studied in two HCC cell lines. Two polyelectrolyte pairs (biocompatible but not degradable and biodegradable crosslinked with gluteraldehyde) are employed for coating. The capsules are characterized by SEM. LY is successfully loaded inside the core and embedded between polymer layers. MS is used to quantify the loading efficiency by comparing post-loading and core-loading methods, since both coated templates and hollow shells are used as carriers. CLSM confirms dissolution of the pre-formed multilayer upon enzymatic degradation as the method of release, and migration assays demonstrate a higher inhibition efficiency of TGF-beta in tailored biodegradable capsules compared to free LY administration.
An efficient microwave supported synthesis, with a reaction time of only one and a half minute, to prepare boron-modified titania nanocrystals TiO2:(B), was developed. The nanocrystals were obtained by hydrolysis of titanium tetraisopropoxide (TTIP) together with benzyl alcohol and boric acid, and the approach did not need surfactants use and a final calcination step. The produced TiO2:(B) nanocrystals were characterized in detail by low magnification Transmission Electron Microscopy (TEM), Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES), X-Ray Diffractometry (XRD), Micro Raman Spectroscopy. One of the obtained samples was then tested as additive in various amounts in a typical aluminosilicate refractory composition. The effects of these additions in bricks were evaluated, according to UNI EN 196/2005, in terms of thermo-physical and mechanical properties: diffusivity, bulk density, apparent density, open and apparent porosity and cold crushing strength. Bricks microstructure was analysed by Scanning Electron Microscopy (SEM) and energy dispersion spectroscopy (EDS). The bricks obtained with nanoadditives presented improved mechanical characteristics with respect to the typical aluminosilicates, presumably because of a better compaction during the raw materials mixing stage.
In the present work, seven different types of nanocrystals were studied as additives in the formulation of aluminosilicate bricks. The considered nanocrystals consisted of anatase titanium dioxide (two differently shaped types), boron modified anatase, calcium carbonate (in calcite phase), aluminium hydroxide and silicon carbide (of two diverse sizes), which were prepared using different methods. Syntheses aim to give a good control over a particle's size and shape. Anatase titania nanocrystals, together with the nano-aluminium hydroxide ones, were synthesized via microwave-assisted procedures, with the use of different additives and without the final calcination steps. The silicon carbide nanoparticles were prepared via laser pyrolysis. The nano-calcium carbonate was prepared via a spray drying technique. All of the nanocrystals were tested as fillers (in 0.5, 1 and 2 wt. % amounts) in a commercial aluminosilicate refractory (55 % Al2O3, 42 % SiO2). They were used to prepare bricks that were thermally treated at 1300 degrees C for 24 hours, according to the international norms. The differently synthesized nanocrystals were added for the preparation of the bricks, with the aim to improve their heat-insulating and/or mechanical properties. The nanocrystals-modified refractories showed variations in properties, with respect to the untreated aluminosilicate reference in heat-insulating performances (thermal diffusivities were measured by the "hot disk" technique). In general, they also showed improvements in mechanical compression resistance for all of the samples at 2 wt. %. The best heat insulation was obtained with the addition of nano-aluminium hydroxide at 2 wt. %, while the highest mechanical compression breaking resistance was found with nano-CaCO3 at 2 wt. %. These outcomes were investigated with complementary techniques, like mercury porosimetry for porosity, and Archimedes methods to measure physical properties like the bulk and apparent densities, apparent porosities and water absorption. The results show that the nano-aluminium hydroxide modified bricks were the most porous, which could explain the best heat-insulating performances. There is a less straightforward explanation for the mechanical resistance results, as they may have relations with the characteristics of the pores. Furthermore, the nanoparticles may have possible reactions with the matrix during the heat treatments.
In this paper, a method to synthesize anatase TiO2 nanorods by hydrolysis of titanium(IV) isopropoxide (TTIP) in the presence of benzyl alcohol and acetic acid at 210 degrees C was tested. The novelty of the present approach relies on the evaluation of the shape-controlled synthesis of anatase TiO2 nanocrystals via a microwave-solvothermal method in 45 min. The different TiO2 nanocrystals were obtained by tuning the TTIP/acetic acid ratio under optimized synthetic conditions and were characterized in detail by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), micro Raman (together with microphotoluminescence) and FT-IR spectroscopies. The acetic acid coordinated on the nanocrystal surface was removed by the reduction of its carboxyl group via a "super-hydride reaction", and the photocatalytic activity of bare TiO2 nanocrystals, under visible light irradiation, was also evaluated: the best performing TiO2 anatase nanocrystals exhibited a discrete photoactivity, completely degrading Rhodamine B solution in five hours.
The development of alternative deposition techniques is an important step towards the realization of low cost multilayered organic solar cells. While spin-coating needs orthogonal solvents to avoid an intermixing of stacked layers, thermal evaporation is expensive and not applicable to polymers. We show here how an innovative deposition technique called dry spray-coating may represent a promising way to manufacture bulk-hetero-junction (BHJ) and multilayered solar cells. Using standard materials such as poly(3-hexylthiophene-2,5-diyl) and [6,6]-phenyl-C61-butyric acid methyl ester, we achieved efficiency of 2.6% for the BHJ device, while a value of 1.5% was obtained for a bilayer structure using the same solvent for both materials. (C) 2013 AIP Publishing LLC.
A non-aqueous, solvothermal method was applied to the synthesis of TiO(2) nanorods in pure anatase crystal phase using Ti(IV)-isopropoxide. The use of benzyl alcohol as both solvent and reactant was investigated in combination with the addition of acetic acid to the reaction mixture. Various values of the AcOH : Ti(OiPr)(4) molar ratio were realized in the synthesis and tested in order to obtain a significant dimensional and morphological control over the resulting TiO(2) nanostructures, as well as to devise a simple and scalable synthetic protocol. On the basis of the experimental results, a substantially modified version of the well-established "benzyl alcohol route'' was then designed and developed. X-ray diffractometry and transmission electron microscopy revealed that monodisperse anatase nanorods having a length of about 13-17 nm and a diameter of 5 nm can be obtained when AcOH and Ti(OiPr)(4) are reacted in comparable proportions. Investigation of the characteristic parameters of dye-sensitized solar cells fabricated using the synthesized nanorods as photoanode revealed a power conversion efficiency of about 7.5% corresponding to an improvement of 28% with respect to a commercial spheroidal nanotitania (P25) based reference device.
Three new 2D-pi-A dyes (TK4, TK5 and TK6), composed of diarylamine donor groups, a dibenzofulvenethiophene core as the pi-bridge, and a cyanoacrylic acid anchoring group as the acceptor, have been successfully designed, synthesized, and characterized both experimentally and computationally. The performance in DSSC solar cells has been also studied. Octyloxy chains were introduced on the backbone of the dye, in order to increase donor capability, avoid aggregation side effects and increase physical insulation between electrolyte system and the TiO2 layer. The dye containing the octyloxy chains on the donor group and two thiophene ring as an extension of pi-bridge showed the best photovoltaic performance with a maximum of solar energy-to-electricity conversion yield of 7.8% under AM 1.5 irradiation (100 mW/cm(2)). (C) 2016 Elsevier Ltd. All rights reserved.
A smart nanocarrier system for cancer therapy, based on a recently developed technique for preparing pure nanometric calcium carbonate (CaCO3), was studied. Different approaches were used to obtain sustained release of cisplatin: at first, pure CaCO3 nanoparticles were evaluated as carriers, then the nanoparticles were functionalized with polymer or silanes, and finally they were employed as a substrate to build layer by layer (LbL) self-assembled polyelectrolyte nanocapsules. Loading efficiency and release kinetics were measured. The best loadings were obtained with the LbL nanocapsules, allowing for high loading efficiency and the possibility of controlling the release rate of the drug. The behavior of all the carriers was evaluated on four neoplastic cell lines, representative of different types of neoplastic disease, namely MCF-7 (breast cancer), SKOV-3 (ovarian cancer), HeLa (cervical cancer) and CACO-2 (human epithelial colorectal adenocarcinoma). Negligible cytotoxicity of the nanoparticles, functionalized nanoparticles, and nanocapsules was observed in experiments with all cell lines. Nanocapsules were functionalized with fluorescein isothiocyanate (FITC) in order to track their kinetic of internalization and localization in the cell line by confocal laser scanning microscopy (CLSM). The cytotoxicity of the loaded capsules was evaluated, showing cell survival rates close to those expected for non-encapsulated cisplatin at the same nominal concentration.
The present investigation reported the synthesis of ultrafine anatase titanium dioxide (TiO2) nanocrystals using titanium isopropoxide (TTIP) as precursor in presence of benzyl alcohol as solvent and glucose as capping agent via a microwave-solvothermal method. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption, micro Raman and Fourier transform infrared spectroscopies (FT-IR). From this preparation method it was demonstrated that the obtainable TiO2 nanocrystals were less than 10 nm in mean size, mainly in anatase phase, presenting also a mesoporous structure. The use of glucose as capping agent added in the reaction system played a role in the anisotropic growth of the TiO2 nanocrystals, as evidenced by XRD domain size analysis and promoted an increase of the specific surface area.
In this review we will report on recent advanced in polyelectrolyte capsules for targeted drug delivery (eg of growth factor inhibitor) against epatocarcinoma. Degradable polyelectrolyte multilayers capsules (PMCs) are of particular interest for cancer therapy since under physiological conditions they can be enzymatically degraded upon cell interaction. Small bioactive molecules such as TGF-Beta inhibitors can be incorporated inside them. Nano-to-microscale delivery systems can enhance efficacy at single cell level for targeted therapy. Layer-by-layer (LbL) self-assembled capsules are novel carriers maximizing drug administration and improving antimetastatic activity of TGF-Beta inhibitors in Hepatocellular Carcinoma (HCC).
This study investigates the effects of commercial nanoparticles on thermal and mechanical performance of rigid polyurethane foams. Two different types of nanoparticles are considered as fillers, spherical titania and rod-shaped halloysite clay nanotubes. The aim of this study was to produce rigid polyurethane foams modified with titania nanocrystals and nanohalloysite in order to obtain polyurethanes with improved properties. The laboratory scale-up will be suitable for the production in many branches of industry, such as construction and automotive production. In particular, these foams, added with commercial nanoparticles, characterized by better thermal and mechanical properties, are mainly used in construction for thermal insulation of buildings. The fillers were dispersed in the components, bringing rates up to 10%. In these investigations, the improvement of the thermal properties occurs by adding nanoparticles in the range 4–8% of titania and halloysite. The mechanical properties instead have been observed an improvement starting from 6% of nanoparticles addition. All data are in agreement with scanning electron microscope observations that shown a decrease in the average cell size and an increase in the cell density by adding nanoparticles in foams.
AbstractBackground Selective imaging of lysosomes by fluorescence microscopy using specific fluorescent probes allows the study of biological processes and it is potentially useful also for diagnosis. Lysosomes are involved in numerous physiological processes, such as bone and tissue remodeling, plasma membrane repair, and cholesterol homeostasis, along with cell death and cell signaling. Despite the great number of dyes available today on the market, the search for new fluorescent dyes easily up-taken by cells, biocompatible and bearing bright and long-lasting fluorescence is still a priority. Methods Two thiophene-based fluorescent dyes, {TC1} and TC2, were synthetized as lysosome-specific probes. Results The new dyes showed high selectivity for fluorescent staining and imaging of lysosomes and disclosed high photostability, low toxicity and pH insensitivity in the range 2–10. Conclusions The {TC} dyes exhibited high co-localization coefficients (> 95%) and moderate quantum yields. They showed high biocompatibility and long-term retention, important features for biological applications. General significance The results of the present work disclose a new class of organic dyes with potential wide applications as specific and efficient lysosome probes in the study of various biological processes.
In recent years, the battery of novel promising antiatherogenic tools has been expanded by theemerging nanoparticle technology. Nanoparticles have been present in the scientific literature for at least 40 years, but the field has exploded in the last decade to produce a large number of chemically different structures. Lipoprotein-mimicking nanoparticles and engineered lipoproteins are valuablepromising tools for cardiovascular prevention and therapy.
Extremely lightweight plates made of an engineered PMMA-based composite material loaded with hollow glass micro-sized spheres, nano-sized silica particles and aluminum hydroxide prismatic micro-flakes were realized by cast molding. Their interesting bulk mechanical properties were combined to properly tailored surface topography compatible with the achievement of a superhydrophobic behavior after the deposition of a specifically designed hydrophobic coating. With this aim, we synthesized two different species of fluoromethacrylic polymers functionalized with methoxysilane anchoring groups to be covalently grafted onto the surface protruding inorganic fillers. By modulating the feed composition of the reacting monomers, it was possible to combine the hydrophobic character of the polymer with an high adhesion strength to the substrate and hence to maximize both the water contact angle (up to 157 degrees) and the durability of the easy-to-clean effect (up to 2000 h long outdoor exposure). (C) 2011 Elsevier Inc. All rights reserved.
La malattia di Parkinson (MP) è uno dei più gravi disordini neurologici e colpisce circa l'1% delle persone sopra i 60 anni [1]. Le principali terapie attualmente adottate per il suo trattamento controllano i sintomi della malattia ma non la curano. Al contrario le terapie basate sulla neuroprotezione (tramite molecole antiossidanti) sono in grado di ridurre la gravità della patologia.Il progetto sintetizzerà delle nanoparticelle (NPs) polimeriche funzionalizzate con molecole antiossidanti con comprovati o potenziali effetti terapeutici nel trattamento della MP, ad es. melatonina, augmenter of liver regeneration protein (ALRP), idrossitirosolo e resveratrolo. La superficie di queste NPs verrà inoltre funzionalizzata con dei vettori in grado di veicolarle verso e attraverso determinati siti di interesse (ad es. glucidi per il target del GLUT-1 [2]) riducendo i potenziali effetti collaterali dovuti a una più generale biodistribuzione del farmaco e la quantità di farmaco necessaria per avere un effetto terapeutico significativo, e quindi i costi.Le proprietà di questi nanovettori intelligenti verranno testate in vitro ed in vivo per valutare la loro effettiva capacità terapeutica e la loro biocompatibilità, fino ad arrivare alla definizione di un sistema ottimale con eventuali potenziali applicazioni biomediche.[1] C.W. Olanow, Neurodegeneration and Neuroprotection in Parkinson's Disease, Academic Press, New York, 1996.[2] M.A. Malvindi et al. Nanoscale 2011, 3, 5110.
The developed technology allows to synthetize pure calcium carbonate nano-particles without using surfactants or other chemical species useful to stabilize the mixture and the reaction product, but using a Spray Dryer which is easily usable on large scale and which allows to control the shape and the size of obtained nanoparticles.
Method for the preparation of nanoparticels of titanium dioxide comprising the steps of adding in an autoclave a predetermined quantity of a titanium precursor to a solvent and in the following adding an acid additive; maintaining the temperature of the solution at a predetermined value, preferably by providing energy to the solution by means of microwaves, for a specific reaction time; carrying out washings with dichloromethane and/or diisopropyl ether and/or methanol and then drying the product obtained.
The present invention relates to a process for the preparation of materials with nanometric dimensions and controlled shape, based on titanium dioxide. The invention also relates to a process for the preparation of titanium dioxide nanorods and nanocubes with anatase phase composition, which are highly suitable for photocatalytic use, in particular for applications involving photovoltaic cells, for example Dye Sensitized Solar Cells (DSSC), photoelectrolysis cells and tandem cells for the conversion of solar energy and the production of hydrogen.
The present invention relates to an industrial applicable process for the preparation of materials with nanometric dimensions and controlled shape, based on titanium dioxide. The invention also relates to a process for the preparation of titanium dioxide nanorods with anatase phase composition, which are highly suitable for applications involving photovoltaic cells, particularly Dye Sensitized Solar Cells (DSSC), photoelectrolysis cells and tandem cells for the conversion of solar energy and the production of hydrogen.
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