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Viviana Vergaro
Ruolo
Ricercatore a tempo determinato - tipo A
Organizzazione
Università del Salento
Dipartimento
Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali
Area Scientifica
Area 03 - Scienze chimiche
Settore Scientifico Disciplinare
CHIM/03 - Chimica Generale e Inorganica
Settore ERC 1° livello
Non Disponibile
Settore ERC 2° livello
Non Disponibile
Settore ERC 3° livello
Non Disponibile
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.
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.
In this review we will overview novel nanotechnological nanocarrier systems for cancer therapy focusing on recent development in polyelectrolyte capsules for targeted delivery of antineoplastic drugs against cancer cells. Biodegradable polyelectrolyte microcapsules (PMCs) are supramolecular assemblies of particular interest for therapeutic purposes, as they can be enzymatically degraded into viable cells, under physiological conditions. Incorporation of small bioactive molecules into nano-to-microscale delivery systems may increase drug's bioavailability and therapeutic efficacy at single cell level giving desirable targeted therapy. Layer-by- layer (LbL) self-assembled PMCs are efficient microcarriers that maximize drug's exposure enhancing antitumor activity of neoplastic drug in cancer cells. They can be envisaged as novel multifunctional carriers for resistant or relapsed patients or for reducing dose escalation in clinical settings
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.
Halloysite is natural aluminosilicate clay with hollow tubular structure which allows loading with low soluble drugs using their saturated solutions in organic solvents. Resveratrol, a polyphenol known for having antioxidant and antineoplastic properties, is loaded inside these clay nanotubes lumens. Release time of 48 h is demonstrated. Spectroscopic and ζ-potential measurements are used to study the drug loading/release and for monitoring the nanotube layer-by-layer (LbL) coating with polyelectrolytes for further release control. Resveratrol-loaded clay nanotubes are added to breast cell cultures for toxicity tests. Halloysite functionalization with LbL polyelectrolyte multilayers remarkably decrease nanotube self-toxicity. MTT measurements performed with a neoplastic cell lines model system (MCF-7) as function of the resveratrol-loaded nanotubes concentration and incubation time indicate that drug-loaded halloysite strongly increase of cytotoxicity leading to cell apoptosis.
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.
The sonication-assisted layer-by-layer (SLBL) technology was developed to combine necessary factors for an efficient drug-delivery system: (i) control of nanocolloid size within 100 - 300 nm, (ii) high drug content (70% wt), (iii) shell biocompatibility and biodegradability, (iv) sustained controlled release, and (v) multidrug-loaded system. Stable nanocolloids of Paclitaxel (PTX) and lapatinib were prepared by the SLBL method. In a multidrug-resistant (MDR) ovarian cancer cell line, OVCAR-3, lapatinib/PTX nanocolloids mediated an enhanced cell growth inhibition in comparison with the PTX-only treatment. A series of in vitro cell assays were used to test the efficacy of these formulations. The small size and functional versatility of these nanoparticles, combined with their ability to incorporate various drugs, indicates that lapatinib/PTX nanocolloids may have in vivo therapeutic applications.
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.
Oil bodies (OBs) are specialised organelles ubiquitously detected in plant oil seeds, which serve as lipid storage compartments. OBs consist of a hydrophobic core of triacylglycerol (TAGs), surrounded by a monolayer of phospholipids (PLs) embedded with some specific proteins with a size ranging from 0.5 to 2 μm. In this work, we report an easy method to reconstitute OBs starting fromtheir constituents and to encapsulate lipophilic molecules, i.e. the fluorescent fluorescein isothiocyanate (FITC) and carboxyfluorescein (CF), into reconstituted OBs. This methods allowed us to produce OBs 4- to 10-fold smaller (50–200 nm) than the native one and to obtain a good recovery (about 40%) of both the fluorescent compounds used in the present work. The properties of reconstituted OBs were investigated by a combination of Brewster angle microscopy, scanning force microscopy, ζ-potential techniques. OBs were stable and formed ordered monolayers when patterned on hydrophobic substrates whereas they showed a higher tendency to aggregate into larger, coalescing OBs when were deposited onto hydrophilic substrates or at the air/water interface. Furthermore, we verified the uptake of FITC- loaded OBs by the MCF-7 breast cancer cell line. Our results indicated that OBs could be envisaged as novel carriers to deliver hydrophobic bioactive compounds
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.
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.
Phytochemicals constitute a heterogeneous group of substances with an evident role in human health. Their properties on cancer initiation, promotion and progression are well documented. Particular attention is now devoted to better understand the molecular basis of their anticancer action. In the present work, we studied the effect of resveratrol on the ovarian cancer cell line OVCAR-3 by a proteomic approach. Our findings demonstrate that resveratrol down-regulates the protein cyclin D1 and, in a concentration dependent manner, the phosphorylation levels of protein kinase B (Akt) and glycogen synthase kinase-3β (GSK-3β). The dephosphorylation of these kinases could be responsible for the decreased cyclin D1 levels observed after treatment. We also showed that resveratrol reduces phosphorylation levels of the extracellular signal-regulated kinase (ERK) 1/2. Chemical inhibitors of phosphatidylinositol 3-kinase (PI3K) and ERK both increased the in vitro therapeutic efficacy of resveratrol. Moreover, resveratrol had an inhibitory effect on the AKT phosphorylation in cultured cells derived from the ascites of ovarian cancer patients and in a panel of human cancer cell lines. Thus, resveratrol shows antitumor activity in human ovarian cancer cell lines targeting signalling pathway involved in cell proliferation and drug-resistance.
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.
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.
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.
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