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Xyloglucans are highly branched, hydroxyl rich polyglucans that for their abundance in nature, biocompatibility, film forming and gelation ability may take a prominent role in the design and fabrication of biomedical devices, including in situ forming scaffolds for tissue engineering, wound dressings and epidermal sensors. The understanding and exploitation of their self-assembly behavior is key for the device performance optimization. A multi-scale analysis, conducted combining small-angle X-ray scattering, both static and dynamic light scattering at large and small angles, and rheological measurements, provides a description of the supramolecular organization of this biopolymer, from the scale of a few nano-meter, to the meso- and macro-scale both in the sol and gel states. Xyloglucan self-assembly is described as multi-step and hierarchical process with different levels of organization.

In this work we have explored the nature of macroradicals formed upon radiolysis of aqueous poly(N-vinylpyrrolidone) (PVP) solutions using pulse radiolysis, density functional theory (DFT) and literature data. On the basis of literature data on site-specific kinetics of hydrogen abstraction from simple amides and spectra corresponding to specific radical sites on the same amides we have assessed the distribution of H-atom abstraction by `OH radicals from different positions on the pyrrolidone ring and the polymer backbone. Pulse radiolysis experiments performed at different doses per pulse and different PVP concentrations demonstrate that the H-abstracting radiolysis products are not quantitatively scavenged by the polymer when the dose per pulse exceeds approximate to 40 Gy. The implications of this are discussed in the context of radical-initiated crosslinking reactions. At a mass fraction of 0.1% PVP and doses per pulse ranging from 7 Gy to 117 Gy, the overall radical decay observed at 390 nm follows second order kinetics with rate constants on the order of 10(9) dm(3) mol(-1) s(-1).

Injectable, in-situ forming kefiran gels have been developed for potential applications as implantable drug delivery devices or scaffolds for tissue regeneration. Concentrated solutions (4, 5 and 6%w) of kefiran, extracted from kefir grains, have been assessed in term of viscosity and injectability through G26 syringe needles, and for their ability to undergo gelation upon mixing with different alcohols. Propylene glycol (PG) has been selected as gelling agent because it ensures homogenous gelation in relatively short times (from few minutes up to 6 h). The investigation of the rheological behavior of kefiran/PG gels varying polymer concentration and temperature (25 degrees C and 37 degrees C) has provided interesting hints to support a possible gelation mechanism that accounts also for the observed influence of the alcohol type. Finally, the study of kefiran/PG gels has been complemented with the investigation on selected formulations of the swelling/degradation behavior upon immersion in isotonic buffer solution for up to 40 days at 37 et; of the ability of the gels to retain and/or release two model molecules; and within vitro cell viability and cytotoxicity tests, to support the absence of toxic effects on cells induced by direct contact with the gels or by leached components from these gels. (C) 2020 Elsevier B.V. All rights reserved.

Partially degalactosylated xyloglucan from tamarind seeds (Deg-XG) is a very appealing biopolymer for the production of in situ gelling systems at physiological temperature. In this work, we observe that the morphology of hydrogels evolves towards high degrees of structural organization with time, yielding to dense stacks of thin membranes within 24 h of incubation at 37 °C. We also explore the possibility offered by gamma irradiation of controlling the time scale of this phenomenon, the final morphology and mechanical properties of the system. Structural and molecular modifications of Deg-XG with dose are investigated by FTIR, dynamic light scattering (DLS) and rotational viscosimetry. The impact on gelation ability and gel strength is studied by rheological analysis. The morphology evolution is investigated by SEM analysis, and absence of cytotoxicity verified by MTS assay and optical microscopy of neuroblastoma cells.

Electrospun mats have been applied as toughening interlayers in high performance carbon fiber epoxy composites. While the toughening mechanism exerted by the mat at the interface is the subject of several recent studies, no investigations are reported on the aging behaviour of laminates comprising these nanostructured elements. This work investigates the influence of the combined effect of water and temperature (90 °C) on laminates with Nylon 6,6 electrospun membranes placed either at the middle plane only or at each interlayer. The water-uptake behaviour is modelled by a two-stage diffusion model and compared with the behaviour of the neat resin and of the laminate without mats. Interestingly, a lower water uptake is observed for the laminates with mat-modified interfaces and this is possibly due to a significantly reduced porosity. The effect of hydrothermal aging on the thermal (Tg) and mechanical properties (transverse flexural modulus and interlaminar shear strength) of the various laminates is also investigated.

Nanogels are very promising biomedical nanodevices. The classic “radiation chemistry-based” approach to synthetize nanogels consists in the irradiation with pulsed electron beams of dilute, N2O-saturated, aqueous solutions of water-soluble polymers of the “crosslinking type”. Nanogels with controlled size and properties are produced in a single irradiation step with no recourse to initiators, organic solvents and surfactants. This paper combines experimental syntheses, performed with two e-beam irradiation setups and dose-ranges, starting from poly(N-vinyl pyrrolidone) solutions of various concentrations, both in N2O-saturated and air-saturated initial conditions, with the numerical simulations of the radiation chemistry of aqueous solutions of a radical scavanger exposed to the same irradiation conditions used in the experiments. This approach provides a methodology to predict the impact of system and irradiation conditions on the water radiation chemistry, which in turn affect the nanogel features in terms of molecular and physico-chemical properties. In particular, the crucial role of initial and transient concentration of molecular oxygen is revealed. This work also proposes a very simple and effective methodology to quantitatively measure the double bonds formed in the systems from disporportionation and chain scission reactions, competing with inter-/intra-molecular crosslinking.

In-situ generation of a nanodispersed conductive polymer within a polypropylene matrix has been pursued in order to obtain flexible, conductive films. Radiation grafting of acrylic acid to polypropylene (PP) has been applied to insert carboxyl functionalities on PP. The radiation-grafted films have been further derivatized with a variety of diamines and used as substrates for in-situ chemical oxidative polymerization of polyaniline (PANI). PANI grows as a thin skin from the surface of the film as well as an interpenetrated network in its interiors. Evidence of chemical attachment of PANI to PP has been sought by performing FTIR and XPS analyses after extraction of the unbound polymer. The influence of the nature of the substituent attached to PP on the optical and electrical properties of the films has been investigated. PANI-PP skin-core films have been also tested as flexible electrodes for further electrochemical growth of the conductive polymer.

Thin xyloglucan-based hydrogel films have been synthetized and characterized in the prospect of producing wound dressings. Polyvinyl alcohol (PVA) and glycerol (Gro) were added to have an optimal combination of softness, conformability and resilience. Physical hydrogels have been transformed into permanent covalent hydrogels by reaction with glutaraldehyde (GA). Network structure-process-property relationships are discussed on the account of the results of several complementary characterizations: FTIR, rheology, thermal analysis, morphological analysis, moisture retention and swelling measurements. Selected formulations were also subjected to preliminary in vitro cytotoxicity tests. The physical and mechanical properties of some of the xyloglucan-based hydrogel films produced, combined with absence of cytotoxicity, make them suitable candidates for integration with sensors to monitor the wound healing process and further biological investigations in animal models.

Recent evidences suggest that insulin delivery to the brain can be an important pharmacological therapy for some neurodegenerative pathologies, including Alzheimer disease (AD). Due to the presence of the Blood Brain Barrier, a suitable carrier and an appropriate route of administration are required to increase the efficacy and safety of the treatment. Here, poly(N-vinyl pyrrolidone)-based nanogels (NG), synthetized by e-beam irradiation, alone and with covalently attached insulin (NG-In) were characterized for biocompatibility and brain delivery features in a mouse model. Preliminarily, the biodistribution of the "empty" nanocarrier after intraperitoneal (i.p.) injection was investigated by using a fluorescent-labeled NG. By fluorescence spectroscopy, SEM and dynamic light scattering analyses we established that urine clearance occurs in 24 h. Histological liver and kidneys inspections indicated that no morphological alterations of tissues occurred and no immunological response was activated after NG injection. Furthermore, after administration of the insulin-conjugated nanogels (NG-In) through the intranasal route (i.n.) no alteration or immunogenic response of the nasal mucosa was observed, suggesting that the formulation is well tolerated in mouse. Moreover, an enhancement of NG-In delivery to the different brain areas and of its biological activity, measured as Akt activation levels, with reference to free insulin administration was demonstrated. Taken together, these results indicate that the synthesized NG-In enhances brain insulin delivery upon i.n. administration and strongly encourage its further evaluation as therapeutic agent against some neurodegenerative diseases.

Administered by an oral route, Furosemide (FUR), a diuretic used in several edematous states and hypertension, presents bioavailability problems, reported as a consequence of an erratic gastrointestinal absorption due to various existing polymorphic forms and low and pH-dependent solubility. A mucoadhesive sublingual fast-dissolving FUR based film has been developed and evaluated in order to optimize the bioavailability of FUR by increasing solubility and guaranteeing a good dissolution reproducibility. The Differential Scanning Calorimetry (DSC) analyses confirmed that the film prepared using the solvent casting method entrapped FUR in the amorphous state. As a solid dispersion, FUR increases its solubility up to 28.36 mg/mL. Drug content, thickness, and weight uniformity of film were also evaluated. The measured Young’s Modulus, yield strength, and relative elongation of break percentage (EB%) allowed for the classification of the drug-loaded film as an elastomer. Mucoadhesive strength tests showed that the force to detach film from mucosa grew exponentially with increasing contact time up to 7667 N/m2. FUR was quickly discharged from the film following a trend well fitted with the Weibull kinetic model. When applied on sublingual mucosa, the new formulation produced a massive drug flux in the systemic compartment. Overall, the proposed sublingual film enhances drug solubility and absorption, allowing for the prediction of a rapid onset of action and reproducible bioavailability in its clinical application.

Responsive hydrogels filling the interstitial spaces of photonic crystals can form mesoscopically structured materials, which exhibit reversible shifts in the Bragg diffracted light as a response of environmental changes. These materials can be used to generate chemical or biochemical sensors. The present work reports on the synthesis and characterization of ethanol responsive hydrogels that can be used in the design of novel breathalyzers. The dynamic mechanical behavior of the macroscopic hydrogels and their swelling features in the presence of different liquids or vapors have been investigated to orientate the choice of the best responsive material and curing process. The swelling behavior of a selected hydrogel embedding the photonic crystal made of polystyrene nanoparticles as function of the concentration of ethanol vapor was studied through UV–Vis optical transmission spectroscopy and compared to the behavior of the macrogel analogue.

In this work, a new method for numerical simulation of the radiation chemistry of aqueous polymer solutions exposed to a sequence of electron pulses is presented. The numerical simulations are based on a deterministic approach encompassing the conventional homogeneous radiation chemistry of water as well as the chemistry of polymer radicals. The multitude of possible reactions in the macromolecular system is handled by allowing for a large number of macromolecular species. The speciation of macromolecular species is done to account for variations in molecular weight, number of alkyl radicals per chain, number of peroxyl radicals per chain, number of oxyl radicals per chain, and number of internal loops. As benchmarking, previously published results from a series of experiments on pulsed irradiation of aqueous poly(N-vinylpyrrolidone) (PVP) solutions are used. The numerical simulations clearly show that the pulsed nature of the radiation must be accounted for. The simulations qualitatively reproduce the experimentally observed impact of initial gas saturation (air and N2O) and polymer concentration on the molecular chain length upon irradiation. The formation of double bonds as a function of dose as well as the impact of effective dose rate on the final chain length are also qualitatively reproduced in the simulations.

Poly(N-vinylpyrrolidone)-grafted-acrylic acid biocompatible nanogels (NGs) were prepared using an exiting industrial-type electron accelerator and setups, starting from semi-dilute aqueous solutions of a commercial PVP and the acrylic acid monomer. As a result, NGs with tunable size and structure can be obtained quantitatively. Sterility was also imparted at the integrated dose absorbed. The chemical structure of the NGs produced was confirmed through Fourier Transformer Infrared Spectroscopy (FT-IR). The molecular and physico-chemical properties of NGs, such as the hydrodynamic dimensions and surface charge densities, for various polymer and monomer concentrations in the irradiated solutions, are discussed here.

In this work a DGEBF epoxy monomer was cured by electron beam radiation in the presence of an iodonium salt and the obtained system was hydrothermally aged as such and also after a thermal treatment, in order to obtain two systems having different uniformity in the cross-linking degree. On both systems, the transient stress field arising from swelling was measured and monitored by an optical Photoelastic technique and the results were commented with reference to a thermally cured epoxy system containing the same monomer and already discussed in a previous work. Beam samples with identical dimensions, obtained from the irradiated systems, have been aged at 80 °C in water, and characterised by Gravimetric and DMTA tests. The results are compared also with already reported swelling behaviour of similar thermally cured systems. It is observed that the different curing techniques (radiation curing, radiation curing followed by thermal curing and thermal curing) determine a different network structure and a different water chemical affinity, which influence the amounts of absorbed/desorbed water, and the relative amounts of bonded/free water. Such differences affect the swelling behaviour, and then the transient stress field. Photoelastic Stress Analysis has allowed to evaluate the evolving stress field, providing a different point of view on the investigation of the material transformations associated to water diffusion.

Nanogels (NGs) are 3D networks of crosslinked hydrophilic polymers with nanoscalar dimensions. Due to their structure and physico-chemical properties, they are a promising nanomaterial platform for site-specific drug delivery and diagnostic nanodevices.

In this work, the H2O2 build-up for several system compositions and irradiation conditions was investigated, by using the Ghormley triiodide method. Interestingly, the application of the method has revealed the occurrence of two concurrent reactions, the expected one responsible for the I3 - production (by reaction with the H2O2 formed upon irradiation) and one that is responsible for I3 - consumption. Both the concentrations of I3 - -forming and I3 - -consuming species are dose-dependent and polymer concentration-dependent. The kinetic study of the two reactions and some further experiments carried out with model molecules will be described. We believe that the results of this study can offer new insights on the mechanism of nanogels formation.

Cross-linking polymerization initiated by high energy radiation is a very attractive technique for the production of high performance composite materials. This method in fact offers many advantages compared to conventional thermal curing processes, due to the possibility to operate at mild temperature and in short time, limiting both energy and time consuming [1-2]. High performance composite materials mainly consist of epoxy resins as matrix and carbon fibers as reinforce, due to their excellent properties in terms of thermal and mechanical resistance. An important requirement of such systems for structural applications is their ability to maintain the properties within a fixed range during their operative life, i.e. to show significant resistance to the external aging factors. Among them, one of the recurrent ageing conditions is hydrothermal ageing, due to both temperature cycles and water absorption-desorption [3]. These conditions induce some important modification in the thermo-mechanical behaviour of epoxies, including plasticisation and degradation of the network, with a general lowering of the glass transition temperature, modification of the strength and fracture toughness, and swelling which may induce important localized internal stresses [4]. All these phenomena are very difficult to investigate, due to the several mutual effects occurring, and to a lack of reliable and simple measuring techniques. Some of the authors have recently proposed a new approach to evaluate the transitory swelling/un-swelling stresses, by means of Photoelastic Stress Analysis (PSA) [5]. This technique provided a robust method to evaluate the material in terms of its ability to swell and to develop internal stresses, correlating this property to the kinetics of water uptake and to the thermal and mechanical properties of epoxies. In this work electron beam curing was used in order to obtain two epoxy resin systems with very different cross-linking features in terms of both crosslinking homogeneity and water chemical affinity. The different stress behaviour of the irradiated systems upon water absorption/desorption was investigated by means of PSA and the results were interpreted on the basis of the comparison to those of the same monomer thermally cured. The results evidenced the strict correlation between network structure of the resins and swelling induced internal stresses, allowing to evaluate the evolving stress field and providing a different point of view on the investigation of differently crosslinked structures associated to water diffusion.

Soft and flexible nanogels, produced by electron beam (e-beam) irradiation of poly(N-vinyl pyrrolidone) and acrylic acid, were evaluated as delivery devices of the inhibitor of miR-31, a small RNA molecule with an important role in colorectal cancer (CRC) progression. The nanogel carriers developed possess both carboxyl and primary amino groups; the former were activated to react with the primary amino group present in the purposely-functionalised AntimiR-31. Very high conjugation reaction yields were attained, as well as a remarkable colloidal and storage stability of the conjugates. The ability of these nanoconstructs to be internalized by cells and the specific interaction of conjugated AntimiR with its biological target, without being detached from the nanogel, was demonstrated in vitro. These results are a strong encouragement to further proceed in the pre-clinical evaluation of the therapeutic effects of these formulations in CRC.

Study of macromolecular structure and dynamics of networks formed by pulsed electron-beam irradiation of poly(N-vinyl pyrrolidone) (PVP) aqueous solutions, at relatively low energy per pulse and across different concentration regimes, provides the basis for the understanding of a new generation of functional nanostructures. Networks are the result of the follow–up reactions initiated by a continuous series of electron pulse-generated hydroxyl radicals, which may have a different fate at the variance of polymer concentration. Different spectroscopic techniques, FT-IR, 13 C { 1 H} CP-MAS NMR and Raman, applied to characterize the formed networks, describe a profound modification of the chemical structure when network size is approaching the nanoscale. Static light scattering measurements provide further information on the average weight molecular weight modification of PVP when forming nanogel particles. From the simultaneous control of network size and modification of chemical functionality stems also an intrinsic fluorescence of these nanogels never observed before. Altogether the obtained radiation-sculptured nanogels exhibit interesting multifunctionality that, coupled with the already proven biocompatibility, can be exploited in the biomedical field.

In the last twenty years, several nanobiomaterial-based nanocarriers, so-called nanoplatforms, have been proposed for the treatment of life- threating or quality-of-life-impairing diseases. The role of the nanocarrier is to increase drug localisation via passive and active targeting, to protect the drug from degradation and premature clearance, to facilitate its bypass through biological barriers and increase uptake by cells. For a successful translational research, the system composition should be as simple as possible, and the manufacturing processes should be fast, flexible and should enable a rapid product development from lab-scale to low cost, large-scale production. With this focus, we have developed a polymer-based nanoplatform, which adopts as a main manufacturing step an industry-standard EB sterilisation process (10 MeV, 10 kW linac accelerator at INCT, Poland; 300-400 Hz, 20 or 40 kGy per pass). Starting from aqueous solutions of poly(N-vinyl pyrrolidone), varying polymer concentration and absorbed dose, we have obtained a family of nanoscalar polymer networks, or nanogels, with various, controlled particle sizes.Reactive functional groups (carboxyl groups and amino groups) have been generated by irradiation, which contribute to the colloidal stability of the nanoparticles and can be used for covalent conjugation of antibodies and peptides to provide active targeting functions, and therapeutic moelcules. The properties of these nanoparticles as delivery nanodevices, from in-vitro and in vivo studies, will be here presented. Their prospects as nanocarriers for anticancer therapies or for brain targeted insulin delivery in the treatment of Alzheimer's disease will be also discussed.

(1) Background: A new family of nanosystems able to discern between normal and tumor cells and to release a therapeutic agent in controlled way were synthetized by e-beam irradiation. This technique permits to obtain biocompatible, sterile, carboxyl-functionalized polyvinylpyrrolidone (PVP-co-acrylic acid) nanogels (NGs); (2) Methods: Here, we performed a targeting strategy based on the recognition of over-expressed proteins on tumor cells, like the folate receptor. The selective targeting was demonstrated by co-culture studies and flow cytometry analysis, using folate conjugated NGs. Moreover, nanoparticles were conjugated to a chemotherapeutic drug or to a pro-apoptotic siRNA through a glutathione sensitive spacer, in order to obtain a controlled release mechanism, specific for cancer cells. The drug efficiency was tested on tumor and healthy cells by flow cytometric analysis, confocal and epifluorescence microscopy and cytotoxicity assay; the siRNA effect was investigated by RNAi experiment; (3) Results: The data obtained showed that the use of NGs permits a faster cargo release in cancer cells, in response to high cytosolic glutathione level, also improving their efficacy; (4) Conclusion: The possibility of releasing biological molecules in a controlled way and to recognize a specific tumor target allows overcoming the typical limits of the classic cancer therapy.

Xyloglucans (XGs) are interesting substrates for the production of scaffolds for tissue engineering, drug delivery depots and hydrogel dressings, thanks to their ability to gel in appropriate conditions, such as in the presence of hydro-alcoholic solvents or by addition of sugar molecules. Due to their natural source, they are characterized by high average molecular weights and broad molecular weight distributions. High energy irradiation is a suitable tool to reduce polysaccharides molecular weight without a dramatic alteration of the polymer chemical structure and gelation ability. In this work, the effect of the radiation dose on the molecular weight of a XG derived from Tamarind seeds is investigated. The rheological properties of the gels obtained by adding ethanol to the polymer water solutions are also described. The effects of alcohol content, storage time and irradiation dose on gel strength are discussed.

PANI aqueous nanocolloids in their acid-doped, inherently conductive form were synthesised by means of suitable water soluble polymers used as stabilisers. In particular, poly(vinyl alcohol) (PVA) or chitosan (CT) was used to stabilise PANI nanoparticles, thus preventing PANI precipitation during synthesis and upon storage. Subsequently, e-beam irradiation of the PANI dispersions has been performed with a 12 MeV Linac accelerator. PVA-PANI nanocolloid has been transformed into a PVA-PANI hydrogel nanocomposite by radiation induced crosslinking of PVA. CT-PANI nanoparticles dispersion, in turn, was added to PVA to obtain wall-to-wall gels, as chitosan mainly undergoes chain scission under the chosen irradiation conditions. While the obtainment of uniform PANI particle size distribution was preliminarily ascertained with laser light scattering and TEM microscopy, the typical porous structure of PVA-based freeze dried hydrogels was observed with SEM microscopy for the hydrogel nanocomposites. UV−visible absorption spectroscopy demonstrates that the characteristic, pH-dependent and reversible optical absorption properties of PANI are conferred to the otherwise optically transparent PVA hydrogels. Selected formulations have been also subjected to MTT assays to prove the absence of cytotoxicity.

In this paper the network structure of e-beam cured DGEBF based epoxy resins is investigated. Two epoxy systems, having different reactivity and cured in different process conditions, were analyzed through solid state NMR spectroscopy. The analysis shows that the more reactive system has higher cross-linking density and higher uniformity of network distribution. Similar information were obtained, in a previous work, on the same systems through dynamic mechanical thermal analysis. It is worth noting that unlike DMTA tests, which interfere with the molecular structure of the analyzed material, due to the heating during the analysis itself, more reliable information, without any artefact, are obtained by solid state NMR, carried out at constant room temperature.

Surface modification of polymeric films is a way to obtain final products with high performance for many specific and ad hoc tailored applications, e.g. in functional packaging, tissue engineering or (bio)sensing. The present work reports, for the first time, on the design and development of surface modified ethylene–acrylic acid copolymer (EAA) films with polyaniline (PANI), with the aim of inducing electrical conductivity and potentially enable the electronic control of a range of physical and chemical properties of the film surface, via a new “grafting from” approach. In particular, we demonstrate that PANI was successfully polymerized and covalently grafted onto flexible EAA substrates, previously activated. The final hybrid materials and the corresponding intermediates were fully characterized via FTIR, XPS, SEM–EDAX, mechanical and electrical tests. The mechanical properties of the films are not detrimentally affected by each treatment step, while a significant increase in electrical conductivity was achieved for the new hybrid materials.

A model epoxy resin/anhydride system, modified with a polyethersulfone (PES) engineering thermoplastic toughening agent, has been studied under hydrothermal ageing in order to investigate the modification of the thermal, morphological and mechanical behaviour through dynamical mechanical thermal analysis, SEM microscopy and fracture toughness test respectively. Two different concentrations of the toughening agent were used in the blends and two ageing conditions have been considered, consisting of the immersion of the samples in distilled water at constant temperature of 70 °C for 1 week and for 1 month. Dynamical mechanical thermal analysis results on hydrothermally aged materials indicated the occurrence of progressive segregation effects with the formation of regions with different cross-linking degrees. Fracture toughness tests showed an increase of the K IC value with the increase of the toughening agent concentration, revealing both a dramatic decrease of the same parameter after 1 week ageing for all the materials and the tendency to reach an almost constant value after 1 month ageing for all the formulations, with a slight increase with respect to 1 week ageing. These results have been interpreted on the basis of the SEM analysis, showing the presence of a well defined micrometric PES particles distribution in the epoxy/anhydride matrix, and discussed in the light of different water absorption mechanisms at short and long ageing times.

Objective Evaluation of clinical and oncological safety of the modified fronto-lateral laryngectomy in the treatment of T1a-b glottic cancer. Methods Retrospective review of charts of patients managed with classical fronto-lateral laryngectomy or with our modified technique using a cervical fascia flap and a false cord flap to reconstruct the defect. Results No recurrence of cancer was observed in the present series and slight dysphonia was present in all cases. The patients managed with classical technique required a revision surgery for granulations or anterior synechia in 4 cases; those managed with modified technique did not need a second intervention. Conclusion The fronto-lateral laryngectomy should be present in the head-neck surgeon armamentarium. In T1a-b glottic cancer this technique gives a good oncological resection, but the postoperative period requires an intensive rehabilitation process. The modification of the classical technique reduces the incidence of a second intervention.

The hydrothermal ageing of epoxy–thermoplastic blends, used as matrices for carbon fibre composites, cured by electron beam, has been studied. Two different thermoplastic percentages have been adopted. A suitable choice of both curing process and formulation parameters allows to carry out irradiation at mild temperature with several advantages, coming from a “non thermal” process, for both the final properties of the materials and the environment. Nevertheless the occurring of vitrification phenomena needs the use of a short thermal treatment after irradiation on the already solid materials, in order to complete the cure reactions. Radiation cured epoxy based matrices have been subjected to a thermal and moisture absorption ageing treatment and its influence on the thermal and mechanical properties has been investigated through dynamic mechanical thermal analysis and fracture toughness tests. The results have been interpreted on the basis of the different curing degree reached by the investigated systems and in the light of their morphological structures. Plasticization, thermal curing and degradation reactions occur in different extent depending on the kind of the material. In particular, for fracture properties, a better resistance to ageing is shown by the system at higher thermoplastic concentration.

The paper deals with the problem of cold recovery for direct utilization both in the site of regasification facility and far from it. A modular LNG regasification unit is proposed having the regasification capacity of 2 billion standard cubic meters/year of gas. The modular plant is based on use of a power cycle working with ethane or ethylene which allows operation of cold energy transfer, contained in LNG to be regasified, in a range of temperatures suitable for multipurpose use of cold, reducing regasification process irreversibility. Some electric energy is produced by the power cycle, but the own mission of modular unit proposed is addressed to deliver cold suitable for industrial and commercial use in the proper temperature range. The option considers, also, the use of carbon dioxide as a secondary fluid for transfer of cold from regasification site to far end users. This option seems very attractive due to expected wide future exploitation of LNG regasification in the world. Results of a detailed thermodynamic and economic analysis demonstrate the suitability of the proposal.

A family of poly(amino acid)-maleic anhydride hydrogels were designed and synthesized. Water soluble polymeric precursors were prepared by partially substituting the hydroxyl groups of the α,β-poly( N -2-hydroxyethyl)- dl -aspartamide backbone with maleic anhydride, so as to provide double bonds for crosslinking and carboxylic acid groups for pH and electric field responsiveness. Reaction conditions (reactive mixture composition and catalysis) were systematically varied in order to obtain PHEA–MA precursors with different and reliable graft-maleic anhydride levels. PHEA–MA precursors were characterised by titration, Nuclear Magnetic Resonance ( 1 H NMR), Fourier-Transformed Infrared Spectroscopy (FTIR) and Size Exclusion Chromatography (SEC) for structural and molecular determination. Aqueous solutions of selected PHEA–MA precursors were subjected to gamma-irradiation at different irradiation doses and polymer to water concentrations in order to induce chemical crosslinking without the addition of crosslinking agents. The yield of crosslinking reactions was evaluated by solubility tests as well as the effect of ammonium persulphate, as assistant radical initiator for gamma crosslinking. Selected hydrogels were tested through swelling measurements to prove their pH and electric field responsiveness. Structural features of the different variants produced were related to the swelling behaviour.

In liquefied natural gas (LNG) regasification facilities, for exergy recovery during regasification, an option could be the production of electric energy recovering the energy available as cold. In a previous paper, the authors propose an innovative process which uses a cryogenic stream of LNG during regasification as a cold source in an improved combined heat and power (CHP) plant. Considering the LNG regasification projects in progress all over the World, an appropriate design option could be based on a modular unit having a mean regasification capacity of 2 × 109 standard cubic meters/year. This paper deals with the results of feasibility studies, developed by the authors at DREAM in the context of a research program, on ventures based on thermodynamic and economic analysis of improved CHP cycles and related innovative technology which demonstrate the suitability of the proposal.

Nanogels are nanoscalar polymeric networks, characterized by a dynamic internal structure and a flexible adaptive shape. When they are used as drug carriers, their flexibility and shape changing ability can facilitate the bypass of biological barriers, ensure protection of the payload and enable interaction of any attached ligand with its receptors. Poly(N-vinyl pyrrolidone)-co-acrylic acid nanogels (NGs) have been produced by ebeam irradiation of diluted aqueous solutions of a water-soluble polymer in the presence of a small amount of acrylic acid. In particular, industrial accelerators and the typical set-ups and doses applied for sterilization have been used. [1, 2] Particle size, molecular weight and functionalization can be controlled by a proper selection of polymer concentration and irradiation parameters, such as dose-rate and total dose imparted [3]. In recent years, a growing body of evidence has linked insulin resistance and insulin action to Alzheimer’s Disease (AD), a condition also referred to as Type 3 Diabetes (T3D) [4,5]. Recently, it has been demonstrated that insulin is capable of reducing toxicity induced by A oligomers, the protein mainly involved in AD onset, by inhibition of the intrinsic apoptotic pathway [6]. Moreover, activation of insulin signaling provides a neuroprotective mechanism to counteract oxidative stress, mitochondrial damage and neurodegeneration triggered by A oligomers in neuroblastoma cells [7]. In the present work NGs have been conjugated to insulin (NG-In) to defend the hormone from enzymatic degradation, facilitate its crossing through a blood brain barrier model and protect the LAN5 cells from the damages induced by A oligomers addiction.

A chronic wound is a wound that does not heal in an orderly set of stages and in a predictable amount of time the way most wounds do. Chronic wounds mostly affect people over the age of 60, but a significant proportion is becoming radiation induced chronic wounds caused by cancer radiotherapy. Hydrogels are often used as dressings in the management of a variety of wounds. These materials can help to maintain a moist wound environment, promote natural debridement, hydrate necrotic tissue, absorb slough and exudates.We are developing hydrogel dressings that can enable constant monitoring of selected key parameters through embedded radio-sensors, providing information on the progress of the reparative process, while maintaining the wound hydrated and oxygenated.Xyloglucan (XG) has been chosen asmain component of the hydrogel wound dressings. Chemical crosslinking has been induced to improve the mechanical properties of the films and prevent erosion. The effect of glycerol, used as plasticizer, on the structural and mechanical properties of the hydrogels has been investigated.Selected films resulted easy to handle, flexible and conformable, able to absorb high amounts of simulated biological fluids. Film biocompatibility and hemocompatibility was demonstrated by biological tests in which no injurious response was activated. Furthermore, we found that epithelial cells can partially adhere to the film whose ability to inhibit microorganisms growth and invasion was also demonstrated. The best candidate is now being integrated with a RFID radio-sensor to monitor the amount of exudates.

Radiation-engineered poly(N-vinyl pyrrolidone) nanogels are very interesting biocompatible nanocarriers for i.v. administration of therapeutics and contrast agents for bioimaging. The manufacturing process is fast and effective, it grants excellent control of particle size and simultaneous sterilization of the formed nanogels. Interestingly, primary amino groups and carboxyl groups, useful for (bio)conjugation, are also formed in a dose-dependent fashion. In this paper, by means of both numerical simulations and experiments, the origin of nanogel size control and functionalization is investigated. This understanding offers a new dimension for the design and production of radiation-sculptured multifunctional nanocarriers from aqueous solutions of polymers.

A growing body of evidence shows that Insulin, Insulin Receptor (IR) and IR signaling are involved in brain cognitive functions and their dysfunction is implicated in Alzheimer’s disease (AD) degeneration. Thus, administration of insulin could be a strategy for AD treatment. For this aim we have designed, synthesized and characterized a nanogel system (NG) to deliver insulin to the brain, as a tool for the development of a new therapy for AD. A carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system produced by ionizing radiation was chosen as substrate for the covalent attachment of insulin or fluorescent molecules relevant for its characterization. Biocompatibility of the naked carrier was demonstrated by absence of cytotoxicity, oxidative stress and mitochondrial dysfunction. Hemocompatibility was demonstrated by hemolysis, coagulation time, leukocyte proliferation and inflammatory response tests. By immonufluorescence measurements we demonstrated that insulin conjugated to the NG (NG-In) is preotected by protease degradation and is able to bind and activate insulin receptor bringing to trigger the insulin signalling via AKT activation. Moreover, to provide consistent evidence on the functionality of the conjugated insulin on the glucose levels, the effect of NG-In was tested in mice demonstrating that plasma glucose levels was reduced. Neuroprotection of NG-In against dysfunction induced by amyloid β, a peptide mainly involved in AD, was verified. Finally, the potential of NG-In to be efficiently transported across the Blood Brain Barrier was demonstrated by using an in vitro system. All together these results indicated that the synthesized NG-In was a suitable vehicle system for insulin delivery in biomedicine and a very promising tool to develop new therapies for neurodegenerative diseases. The research eas supported by MIUR, FLAGSHIP PROJECT NanoMAX.

A growing body of evidence shows that Insulin, Insulin Receptor (IR) and IR signalling are involved in brain cognitive functions and their dysfunction is implicated in Alzheimer’s disease (AD). Thus, administration of insulin could be a strategy for AD treatment. For this aim we have designed, synthesized and characterized a nanogel system (NG) that has been conjugated to insulin molecules (NG-In) (1) as new therapeutic approach against AD. In our preclinical studies in mice, intraperitoneal injection of fluorescent-labeled NG has allowed to determine the biodistribution of NG vs time in the whole body and its clearance through the kidneys and bladder. Furthermore, we have observed that mice injected with nanogel did not experience stress, discomfort, nor mortalities have been recorded during the observation time. Thus, we may conclude that under our experimental conditions, nonogels did not cause any toxic effects and they are eliminated in urine. The administration of NG-In through the intranasal route to study its brain distribution has been done. Data have shown that different insulin levels were present in brain areas when the protein is conjugated with nanogels with respect to the free insulin. These results indicate that the synthesized NG-In is a suitable carrier for insulin delivery in the brain having a higher efficiency than free-insulin. 1. Picone, P. et al, (2016) Biomaterials 80: 179-94

Xyloglucan is a natural polysaccharide present as storage material in seeds and structural materials in the primary cells walls of higher plants. Xyloglucan from tamarind seed is composed of B(1,4)-D-glucan backbone, partially substituted by a-(1,6)-linked xylose units, some of which are B-D-galactosylated at O-2. In its native form the polymer is water-soluble and forms gel in the presence of moderate amounts of alcohols. When a given fraction of galactosyl residues are removed, the polymer acquires the ability to form gels in aqueous solution at physiological temperatures, a property of great interest for biomedical/pharmaceutical applications. Gelation on increasing temperature can be ascribed to hydrophobic interactions that drive the system into a region of thermodynamic instability. In the highly concentrated regions generated by demixing, the dangling segments of polymeric chains "condensate" into additional intra- and inter molecular bonds forming a more compact structure. The drammatic viscosity increase prevents phase separation to occur and leads to gel formation. Gel morphology and properties are controlled by the relative rate of condensation and gelation, and they are both affected by the molecular weight distribution of the biopolymer. Gamma irradiation of the solid polymer in the form of a dry powder has been carried out to tailor the molecular weight of the polymer without significant alteration of its chemical structure. As a result, temperature induced gelation leads to gels with vaious degrees of structural order, from disordered porous networks for the non-irradiated system to a fairly ordered stack of thin membranes for the system irradiated at 20 kGy. Gamma irradiation of the polymer as a solid materials in the presence of different gaseous atmospheres and in aqueous solution have been carried out in the attempt to elucidate the radiation chemistry of xyloglucan.

From their first appearance in 1969, when Schnagel and Borwardt reported the radiochemical synthesis of poly(ethylene oxide) microgels by gamma-irradiation, the possibility of generating crosslinked micro- and nanoparticles from ”pure” aqueous solutions of macromolecules, have triggered the imagination of material scientists on the search for ”clean” processes and products for biomedical applications. Thanks to the seminal studies of Rosiak and co-workers, who have clarified, both experimentally and mechanistically, the key role of intra-molecular crosslinking in controlling the particle size, the scientific community has now a powerful tool to design and manufacture radiation-synthetized nanogel particles with a terrific potential in targeted drug delivery therapies. We have recently demonstrated that nanogels can be produced by e-beam irradiation with industrial accelerators and with the typical set-ups and doses applied for sterilization; therefore, the synthesis may not even represent an additional cost in the production process. Particle size, molecular weight and functionalization can be controlled, hence tuned, by selecting the dose rate, the polymer concentration and the total dose imparted, without necessarily adding other chemicals but the crosslinking polymer. The generated functionalized nanocolloids are amenable of decoration with (bio)molecules and cell receptors-specific ligands of therapeutic and/or diagnostic relevance. In particular, the prospects of using insulin-conjugated radiation-synthetized poly(N-vinyl pyrrolidone) nanogels for achieving brain targeted insulin delivery for the treatment of Alzheimer's disease will be presented.

I nanogeli sono nanoparticelle polimeriche reticolate idrofile. La struttura polimerica del nanogelo permette la coniugazione di molecole che possano esplicare azioni terapeutiche, diagnostiche e di indirizzamento attivo su siti bersaglio. Le caratteristiche di flessibilità e conformabilità del nanogelo, e delle sue maglie, ne favoriscono l’attraversamento delle barriere biologiche, l’interazione di eventuali ligandi esposti sulla superfice con i recettori target, un’azione protettiva nei confronti del principio attivo incorporato. L’irraggiamento con radiazioni ionizzanti di soluzioni acquose di polimeri è una metodologia sintetica interamente “water-based”, che garantisce rese elevate e che può conferire sterilità al prodotto. [1] Lo studio presentato illustra la possibilità di produrre nanogeli a base di polivinilpirrolidone con le caratteristiche desiderate in termini di dimensioni e con gruppi funzionali disponibili per reazioni di coniugazione con l’insulina. L’obiettivo è quello di realizzare un nanovettore in grado di veicolare l’insulina al cervello attraverso la mucosa nasale. Studi recenti hanno dimostrato che l’insulina è in grado di ridurre la tossicità del peptide beta amiloide (A, coinvolto nella patogenesi della malattia di Alzheimer (MA), e di esplicare una funzione neuroprotettiva. [2, 3] Sono state studiate le caratteristiche dimensionali del nanosistema, la biocompatibilità e la funzione di protezione dalla tossicità indotta da Anei confronti di cellule di neuroblastoma.

Partially degalactosylated xyloglucans are able to form thermo-reversible gels in aqueous solution at physiological temperature. This property makes them very promising materials for tissue engineering. Moreover, due to a highly branched, hydroxyl group-rich molecular structure, xyloglucans are particularly interesting for manufacturing of micro/nanoparticles to be used as nano-scalar delivery devices of active ingredients in cosmetic and pharmaceutical formulations. Here we present results on the temperature-induced self-assembly of degalactosylated xyloglucan at varying polymer concentration from dilute to semi-dilute regime. Our aim is to investigate the gelation mechanism for gaining information valuable in tailoring structural and mechanical properties of either nanogel particles or macrogel depots. We used static and dynamic light scattering, rheology, and scanning electron microscopy to follow the gelation kinetics and characterize the system in its final state. Results obtained at low polymer concentration show that, on increasing temperature, the polymer chains and pre-existing clusters form larger structures having higher density and homogeneity over the length scale of a few nanometers. Despite the system polydispersity, signatures of concomitant coil-globule and LCST transition can be envisaged. Both demixing and coil-to globule transition are induced by the worsening of the solvent quality with increasing temperature. At increasing polymer concentration, gelation on macroscopic scale occurs quickly, but continuous adjustments are observed over times comparable to those required for nanogel formation. The microstructure of the gel evolves from a disordered arrangement of partially folded sheets, forming large and heterogeneous cavities, to a layered microstructure with regularly stacked sheets connected by filaments and transverse walls. The morphological evolution of the gel suggests the formation of several crosslinking lines suturing the polymeric membranes formed by ribbon-like structures self-assembly.

Nanogels made of bio-compatible hydrophilic polymers can be used in various medical applications such as targeted nano-medicine delivery and imaging agents. Intravenously introduced nanogel-drug conjugates may accumulate in tumors through the enhanced permeability and retention effect. We present our latest results on the synthesis and kinetic analysis of two nanogel systems (1) poly)vinyl pyrrolidone) (PVP) and (2) gelation/polyethylene glycol (GEL/PEG) using ionizing irradiation (g-ray, electron beams). The characteristics of nanogels depend on the radiation synthesis parameters (e.g. total dose, pulse repetition rate, etc.). Specifically, one may tune the parameters to promote the crosslinking reaction within the same polymer chain (intra-crosslinking) and to suppress the crosslinking between two different chains (inter-crosslinking). At higher temperatures (>60°C), there is a disruption of polymer-water hydrogel bonds resulting in a collapsed form. Smaller nanogels can be produced with high repetition rates of the pulsed electron beam irradiation while low dose rate pulses favour inter-molecular crosslinking. The nanogels were analysed using asymmetric flow field-flow fractionation coupled to multi-angle static light scattering and dynamic light scattering detectors. The measured hydrodynamic radius (Rh) of the PVP hydrogels were concentration dependent with a range from 15 to 80 nm with a polydispersity index of 0.2-0.3 and molecular weight of 0.4-13 MDa. On the other hand, the RH of the GEL/PEG mixed nanogels decrease from 350 to 20 nm as function of the dose. Additionally, atomic force images confirm the synthetic approach results in globular shapes. X-rays photoelectron spectroscopy (XPS) measurements confirm that the chemical structure of these nanomaterials closely resemble that of the un-irradiated polymers. Moreover, XPS also provides data on the level of oxidation and enables confirmation of chemical grafting. In addition, pulse radiolysis elucidates the mechanism that leads to nanogel generation. The second order reaction rates constants (k2) of PVP radical recombination are determined to be ca. 1.1-2.8 E9 Lmol-1s-1. The activation energy (Ea) of this reaction is calculated from the Arrhenius plot of PVP radical decay rate constants at the series of temperatures and show 1.0 kcal mol-1 below 60°C. These two measured Ea constants can be explained by the different rate determining mechanisms of PVP radical recombination reaction at two temperature regions. Below 60°C, the low Ea reflects the diffusion controlled polymer radical reaction in a good solvent. But at higher temperatures, above 60°C, polymer chains are segregated from the aqueous solution by micro-phase separation and collapse.

A growing body of evidence shows the protective role of insulin in Alzheimer's disease (AD). A nanogel system (NG) to deliver insulin to the brain, as a tool for the development of a new therapy for Alzheimer's Disease (AD), is designed and synthetized. A carboxyl-functionalized poly(N-vinyl pyrrolidone) nanogel system produced by ionizing radiation is chosen as substrate for the covalent attachment of insulin or fluorescent molecules relevant for its characterization. Biocompatibility and hemocompatibility of the naked carrier is demonstrated. The insulin conjugated to the NG (NG-In) is protected by protease degradation and able to bind to insulin receptor (IR), as demonstrated by immunofluorescence measurements showing colocalization of NG-In(FITC) with IR. Moreover, after binding to the receptor, NG-In is able to trigger insulin signaling via AKT activation. Neuroprotection of NG-In against dysfunction induced by amyloid β (Aβ), a peptide mainly involved in AD, is verified. Finally, the potential of NG-In to be efficiently transported across the Blood Brain Barrier (BBB) is demonstrated. All together these results indicate that the synthesized NG-In is a suitable vehicle system for insulin deliver in biomedicine and a very promising tool to develop new therapies for neurodegenerative diseases.

A facile electrosynthesis route for the preparation of polymer nanogels based on the in situ production of hydroxyl radicals is reported for the first time. Electro-Fenton process with continuous H2O2 electrogeneration and Fe2+ regeneration performs better than electro-oxidation with a boron-doped diamond or dimensionally stable anode for promoting crosslinking of poly(vinylpyrrolidone). Keywords: Electrogenerated hydroxyl radicals, BDD, DSA, Electro-Fenton, Polymer modification, Nanogel

Forward Osmosis is a powerful tool to produce clean water at a low cost if appropriate draw agents and regeneration methods are employed (1). In this frame, stimuli-responsive hydrogels are interesting candidates due to their ability to uptake water and release it under physical stimuli, such as hydrostatic pressure and temperature variations. In particular, temperature-responsive hydrogels that are able to absorb large amount of water at room temperature and release it upon a slight temperature increase are very appealing candidates because they can be regenerated easily and with very low energy consumption (2). Chemical stability and biocompatibility are two further requirements that hydrogels can also exhibit. Hydroxypropyl cellulose (HPC) is a temperature-responsive cellulose derivative, its hydrogels displaying a transition temperature around 42°C (3). This means that HPC-based hydrogels are able to absorb water at room temperature and release it when they are conditioned at temperature higher than 42°C for a few minutes. Besides, this biopolymer has several advantages if compared with synthetic, temperature-responsive polymers: it is non toxic, biodegradable, abundantly present in nature and available in large quantities at a relatively low cost. In this work, chemically crosslinked hydroxypropyl cellulose hydrogels with various crosslinking degrees are produced and evaluated as draw agents in Forward Osmosis. In particular, they are characterized for their swelling/deswelling behavior (in water and NaCl aqueous solutions), morphology, rheological and thermal properties. Their performance in a discontinuous Forward Osmosis unit is assessed.

Controlled synthesis of nanoscalar and nanostructured materials enables the development of novel functional materials with fine-tuned optical, mechanical, electronic, magnetic, conductive and catalytic properties that are of use in numerous applications. These materials have also found their potential use in medicine as vehicles for drug delivery, in diagnostics or in combinations thereof. In principle, nanoparticles can be divided into two broad categories, organic and inorganic nanoparticles. For both types of nanoparticles there are numerous possible synthetic routes. Considering the large difference in nature of these materials and the elementary reactions involved in the synthetic routes, most manufacturing techniques are complex and only suitable for one type of particle. Interestingly, radiation chemistry, i.e., the use of ionizing radiation from radioisotopes and accelerators to induce nanomaterials or chemical changes in materials, has proven to be a versatile tool for controlled manufacturing of both organic and inorganic nanoparticles. The advantages of using radiation chemistry for this purpose are many, such as low energy consumption, minimal use of potentially harmful chemicals and simple production schemes. For medical applications one more advantage is that the material can be sterile as manufactured. Radiation-induced synthesis can be carried out in aqueous systems, which minimizes the use of organic solvents and the need for separation and purification of the final product. The radiation chemistry of water is well known, as are the various ways of fine-tuning the reactivity of the system towards a desired target by adding different solutes. This, in combination with the controllable and adjustable irradiation process parameters, makes the technique superior to most other chemical methods. In this review, we discuss the fundamentals of radiation chemistry and radiation-induced synthesis of nanoparticles in aqueous solutions. The impact of dose and dose rate as well as of controlled addition of various solutes on the final particle composition, size and size distribution are described in detail and discussed in terms of reaction mechanism and kinetics.

Nanogels (NGs), or small particles formed by physically or chemically crosslinked polymer networks, represent a niche in the development of “smart” nanoparticles for drug delivery and diagnostics. Yet, they offerunique advantages over other systems, including a large and flexible surface for multivalent bio-conjugation; an internal 3D aqueous environment for incorporation and protection of (bio)molecular drugs; the possibility to entrap light-activemolecules, metal or mineral nanoparticles for imaging or phototherapeutic purposes; stimuli-responsiveness to achieve temporal and/or site control of the release function and biocompatibility. The availability of inexpensive, robust and versatile synthetic methodologies is at the basis of the development of effective nanogel-based theragnostic devices. In particular, we have established that nanogels can be produced with high yields and through-puts by pulsede-beam irradiation of dilute aqueous solutions of water-soluble biocompatible polymers e.g. poly(N-vinyl pyrrolidone), and functional acrylic monomers, such as acrylic acid or (3-aminopropyl) methacrylamide hydrochloride, using industrial electron accelerators and set-ups (see Figure 1). [1-4] Nanogels are the result of chemical follow-up reactions initiated by a continuous series of electron pulse-generated hydroxyl radicals in de-aerated water. A number of radical sites are generated on the polymer chains,which may have a different fate depending onthe system composition and irradiation conditions.Intra-molecular and inter-molecular radical recombination as well as disproportionation, chain scission and monomer or short polymer segments grafting may occur up to different extent. As a result, crosslinked-core nanoparticles with multi-armed surfaces can be generated, with controlled size, crosslinking density, surface electric charge density, number and nature of functional groups.No recourse to organic solvents, toxic initiators or catalysts and surfactants is made, therefore expensive or time-consuming purification procedures are not required. Simultaneous sterilization can be achieved depending on the irradiation doses. Long-term colloidal stability in the formof aqueous dispersions and redispersability from the freeze-dried form are advantageous properties especially in the view of a pharmaceutical use. Nanogels have been decorated with fluorescent probes, peptides, antibodies or oligonucleotides and/or conjugated to both molecular and macromolecular model drugs to demonstrate their amenability to be transformed into bio-hybrid, smart drug nanocarriers. All the base nanogels have been proved to benot cytotoxic or genotoxic at the cellular level. Indeed, they showed a good affinity for cells, as they rapidly and quantitatively bypass the cellularcompartments, to accumulate in specific cell portions for the first hours, to bethen completely released from the cells after 24 h.[5] In particular, active targeting features toward specific cell types and smart delivery functions of model chemotherapeutics of purposely designed bio-hybrid nanogels will be presented.

The influence of surface treatments on the mechanical strength of adhesive joints was investigated. The attention was focused on AA2024 alloy because it is extensively used in both the automotive and aerospace industries. Adhesive joints fabricated with pure aluminium were also investigated in order to evidence possible differences in the surface features after identical treatments. Before joining with a commercial epoxy adhesive, metal substrates were subjected to different kinds of treatment and the surfaces were characterized by SEM analysis. The formation of a microporous surface in the AA2024 alloy, upon etching and anodizing, is discussed on the basis of the role of the intermetallic particles and their electrochemical behaviour with respect to the aluminium matrix. Moreover, nanostructured porous oxide layers on both type of substrate were also formed, as a consequence of the anodizing process. Differences in their morphologies were revealed as a function of both the applied voltage and the presence of alloying elements. On this basis, an explanation of the different values of fracture energy measured by means of T-peel tests carried out on the corresponding joints was attempted.

A novel electrically conductive composite material, consisting of polyaniline (PANI) nanoparticles dispersed in a polyvinyl pyrrolidone (PVP) hydrogel, was prepared ‘in situ’ by water dispersion polymerisation (DP) of aniline using PVP as steric stabiliser, followed by γ-irradiation induced crosslinking of the PVP component. Conversion yield of aniline into PANI particles was determined via HPLC and gas chromatography, while structural confirmation of the synthesised polymer was sought by FTIR. Morphology and dimensions of PANI particles into the coloured, optically transparent hydrogel was determined by electronic microscopy; moreover, swelling behaviour of composite hydrogels in different buffer solutions was investigated by gravimetric measurements and compared to that of pure PVP hydrogels. Cyclic voltammetry experiments were carried out both on these hydrogels and on the parent aqueous dispersions, at different pH values of the suspending/swelling medium, while conductivity of the composite hydrogels was derived from Impedance Spectroscopy; in both cases results were compared to those relative to hydrogels containing commercial-grade PANI particles.

Polymerization of an acrylate derivative of bisphenol-A by ionizing radiation in the presence of an organically modified montmorillonite was carried out in order to produce a flame-retardant composite. The measurement of the thermal effect during irradiation indicates that radiation curing of pure resin and resin-clay mixtures occurred in both cases. Moreover, differential scanning calorimetry and dynamic mechanical thermal analysis showed that a curing completion can be obtained by thermal curing after irradiation with a significant increase of the glass transition temperature. The morphology was investigated by X-ray diffraction and transmission electron microscopy. These have indicated that gamma irradiation leads to the formation of a microcomposite structure after radiation curing. The flame resistant characteristics were studied by means of thermal gravimetric analysis under nitrogen and air and by cone calorimeter tests. In particular, thermal gravimetric analysis in air showed that the presence of the dispersed clay in the polymer matrix increases the oxidation temperature. This is attributed to the formation of a more stable char, due to a protective skin of clay aggregates that builds up on the surface of the volatilizing polymer matrix during thermal degradation which protects the charred polymer from reactions with oxygen. Finally, the cone calorimeter tests show a reduction of heat release of the clay-polymer composite with respect to the neat resin. The contribution of the clay in reducing the rate of heat release is attributed to the dispersion of the filler that allows build-up of an inorganic surface layer at a rate which is sufficient for effectively compete with the feeding of the flame with combustible pyrolysis products. © 2006 Wiley Periodicals, Inc. Adv Polym Techn 25: 109–120, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20063

It has been widely recognised that high energy radiation can be effectively applied to the cure of epoxy resins in applications as composite matrices or structural adhesives with improvements in product quality and/or reduction in production costs. In the presence of suitable initiators, polymerisation of epoxies occurs via cationic mechanism, thus restricting the choice of the resin system components to species which do not contain electron donor groups. The present investigation is aimed to identify suitable co-monomers to be formulated with an epoxy resin, resulting in different cure reaction kinetics and application properties of the cured resin. In particular, four different anhydride types, three dicarboxylic and one tetracarboxylic, have been formulated at the same weight ratio with a diglydilether of bisphenol F and a photo-initiator. Resin samples, irradiated at different integrated doses, have been characterised with solubility tests, dynamic-mechanical thermal analysis and three point flexural tests, showing a response which is strongly affected by the specific chemical structure of the anhydride co-monomer. Post-irradiation thermal treatments carried out on samples irradiated at the lower dose suggest different reaction patterns, with different controlling factors depending on the activation mechanism (temperature or γ -rays).