The 75-99 C-Terminal Peptide of URG7 Protein Promotes α-Synuclein Disaggregation.

Up Regulation Gene seven (URG7) is the pseudogene 2 of the transporter ABCC6. The translated URG7 protein is localized with its single transmembrane α-helix in the endoplasmic reticulum (ER) membrane, orienting the N- and C-terminal regions in the lumen and cytoplasm, respectively, and it plays a crucial role in the folding of ER proteins. Previously, the C-terminal region of URG7 (PU, residues 75-99) has been shown to modify the aggregation state of α-synuclein in the lysate of HepG2 cells. PU analogs were synthesized, and their anti-aggregation potential was tested in vitro on α-synuclein obtained using recombinant DNA technology. Circular dichroism (CD), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, and microscopic techniques were used to assess the sample's behavior. The results show that the peptides studied by themselves are prone to clathrate-like structure formation of variable stability. Aggregation of α-synuclein is accompanied by desolvation of its peptide chain and an increase in intermolecular ß-sheets. The PU analogs all interact with α-synuclein aggregates and those possessing the most stable clathrate-like structures have the highest disaggregating effect. These findings suggest that the C-terminal region of URG7 may have a role in interacting and modulating α-synuclein structures and could be used to generate interesting therapeutic candidates as disaggregators of α-synuclein.

From speciation study to removal of Pb2+ from natural waters by a carnosine-based polyacrylamide/azlactone copolymer.

A deep speciation study on L-carnosine (CAR) and Pb2+ system was performed in aqueous solution with the aim to assess its potential use as a sequestering agent of metal cation. To determine the best conditions for Pb2+ complexation, potentiometric measurements were carried out over a wide range of ionic strength (0.15 ≤ I/≤ 1 mol/L) and temperature (15 ≤ T/°C ≤ 37), and thermodynamic interaction parameters (logß, ΔH, ΔG and TΔS) were determined. The speciation studies allowed us to simulate sequestration ability of CAR toward Pb2+ under different conditions of pH, ionic strength and temperature and to establish a priori the conditions for the best removal performance, i.e., pH > 7 and I = 001 mol/L. This preliminary investigation was very useful in optimizing removal procedures and limiting subsequent experimental measurements for adsorption tests. Therefore, to exploit the binding ability of CAR for Pb2+ removal from aqueous solutions, CAR was covalently grafted on an azlactone-activated beaded-polyacrylamide resin (AZ) using an efficient click coupling reaction (78.3% of coupling efficiency). The carnosine-based resin (AZCAR) was analyzed by ThermoGravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Differential Thermal Analysis (DTA). Morphology, surface area and pore size distribution were studied through a combination of Scanning Electron Microscope (SEM) and adsorption/desorption of N2 analyses according to the Brunauer-Emmett-Teller (BET) and Barret-Johner-Halenda (BJH) approaches. The adsorption capacity of AZCAR toward Pb2+ was investigated under conditions simulating the ionic strength and pH of different natural waters. The time needed to reach equilibrium in the adsorption process was 24 h, and the best performance was obtained at pH > 7, typical of most natural waters, with removal efficiency ranging from 90.8% (at I = 0.7 mol/L) to 99.0 (at I = 0.001 mol/L).

Graphene Quantum Dots Based Systems As HIV Inhibitors.

Graphene quantum dots (GQD) are the next generation of nanomaterials with great potential in drug delivery and target-specific HIV inhibition. In this study we investigated the antiviral activity of graphene based nanomaterials by using water-soluble GQD synthesized from multiwalled carbon nanotubes (MWCNT) through prolonged acidic oxidation and exfoliation and compared their anti-HIV activity with that exerted by reverse transcriptase inhibitors (RTI) conjugated with the same nanomaterial. The antiretroviral agents chosen in this study, CHI499 and CDF119, belong to the class of non-nucleoside reverse transcriptase inhibitors (NNRTI). From this study emerged the RTI-conjugated compound GQD-CHI499 as a good potential candidate for HIV treatment, showing an IC50 of 0.09 µg/mL and an EC50 value in cell of 0.066 µg/mL. The target of action in the replicative cycle of HIV of the drug conjugated samples GQD-CHI499 and GQD-CDF119 was also investigated by a time of addition (TOA) method, showing for both conjugated samples a mechanism of action similar to that exerted by NNRTI drugs.

Hydroxyapatite-magnetite-MWCNT nanocomposite as a biocompatible multifunctional drug delivery system for bone tissue engineering.

New magnetic hydroxyapatite-based nanomaterials as bone-specific systems for controlled drug delivery have been synthesized. The synthesized hydroxyapatite, HA, decorated with magnetite nanoparticles by a deposition method (HA/Fe3O4) and the nanocomposite system obtained using magnetic multi-walled carbon nanotubes (HA/MWCNT/Fe3O4) as a filler for HA have been characterized by chemical and morphological analyses, and their biological behavior was investigated. The systems have also been doped with clodronate in order to combine the effect of bone biomineralization induced by hydroxyapatite-based composites with the decrease of osteoclast formation induced by the drug. An analysis of the preosteoclastic RAW264.7 cell proliferation by MTT assay confirmed the high biocompatibility of the three systems. TRAP staining of RAW 264.7 conditioned with sRAKL to induce osteoclastogenesis, cultured in the presence of the systems doped and undoped with clodronate, showed the inhibitory effect of clodronate after we counted the MNC TRAP(+)cells but only in the osteoclast formation; in particular, the system HA/Fe3O4-Clo exerted a high inhibitory effect compared to the drug alone. These results demonstrate that the synthesized nanocomposites are a biocompatible magnetic drug delivery system and can represent a useful multimodal platform for applications in bone tissue engineering.

Effect of Sodium Hydroxide and Tripolyphosphate on Curcumin Release from Chitosan-Based Macroparticles.

This work deals with the synthesis of bare and curcumin (CUR)-loaded chitosan (CS)-based macroparticles by ionic gelation using sodium hydroxide (NaOH) or sodium tripolyphosphate (TPP). The resulting spherical-shaped macroparticles were studied using various characterization techniques, Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC). The release of CUR from the CS-based particles with respect to time was analyzed, and the encapsulation efficiency and degree of swelling were studied. All formulations showed excellent CUR trapping efficiency, exceeding 90%. In particular, the TPP-crosslinked macrobeads released 34 wt% of the charged CUR within minutes, while the remaining 66 wt% was released slowly. The results indicate that the correct choice of gelling agent and its concentration leads to spherical particles capable of encapsulating CUR and releasing it in a wide range of kinetics so that macrospheres can be used in different applications.

Lyapunov stability of cable-driven manipulators with synthetic fibre cables regulated by non-linear full-state feedback controller.

Robotic manipulators provide advantages in working environments regarding efficiency and safety, which is further increased in the case of elastic joint manipulators, whose mechanical compliance reduces the energy involved in collisions with workers. Cable-driven manipulators are elastic joint manipulators particularly suitable for industrial inspection thanks to the relocation of actuators outside hostile environments, increasing the manipulator payload-to-weight ratio. Recently, synthetic fibre cables are substituting steel cables due to their better-performing mechanical properties, but their visco-elastic behaviour must be compensated in the controller design. The key novelty of this work is using the four elements model, which includes the viscous behaviour, to design a non-linear full-state feedback controller for cable-driven manipulators. Furthermore, the mathematical proof of the closed-loop Lyapunov stability is provided.

Functionalization of multi-walled carbon nanotubes with coumarin derivatives and their biological evaluation.

We report the synthesis and the characterization of different multi-walled carbon nanotubes (MWCNTs) linked to natural molecules, 5,7-coumarins and/or oleic acid, obtained from purified pristine MWCNTs by a cascade of chemical functionalization. The activities of these modified MWCNTs were investigated in vitro on human umbilical vein endothelial cells (HUVECs) by evaluating their ability to influence cell viability and to induce cell apoptosis. Our data showed that pristine MWCNTs are markedly cytotoxic; conversely, the carboxylated carbon nanotubes, much more readily dispersed in aqueous solutions and CNT-Link, the key intermediate designed by us for the drug anchorage, are biocompatible at the tested concentrations (1 and 10 µg ml(-1)).

Study of Protective Layers Based on Crosslinked Glutaraldehyde/3-aminopropyltriethoxysilane.

In this paper, we report the synthesis and characterization of novel coatings based on (3-aminopropyl)-triethoxysilane (AP) mixed with different amounts of glutaraldehyde (GA). The synthesized coatings have been layered on a glass substrate and characterized by optical microscopy and roughness measurements, thermogravimetric analyses and differential scanning calorimetry, contact angle analysis, rheological measurement, and an adhesion test. It was observed that the higher the GA content (up to AP:GA ratio of 0.3), the sooner the crosslinking reaction starts, leading to a coating with increased hydrophobic and adhesion features without compromising the final AP cross-linked network. Hence, the obtained results show the effectiveness of AP modification with GA from the perspective of an application as protective coatings.

Mechanical Properties of Protective Coatings against Marine Fouling: A Review.

The accumulation of marine organisms on ship hulls, such as microorganisms, barnacles, and seaweeds, represents a global problem for maritime industries, with both economic and environmental costs. The use of biocide-containing paints poses a serious threat to marine ecosystems, affecting both target and non-target organisms driving science and technology towards non-biocidal solutions based on physico-chemical and materials properties of coatings. The review reports recent development of hydrophobic protective coatings in terms of mechanical properties, correlated with the wet ability features. The attention is focused mainly on coatings based on siloxane and epoxy resin due to the wide application fields of such systems in the marine industry. Polyurethane and other systems have been considered as well. These coatings for anti-fouling applications needs to be both long-term mechanically stable, perfectly adherent with the metallic/composite substrate, and capable to detach/destroy the fouling organism. Prospects should focus on developing even "greener" antifouling coatings solutions. These coatings should also be readily addressable to industrial scale-up for large-scale product distribution, possibly at a reasonable cost.

Polyurethane Foams Loaded with Carbon Nanofibers for Oil Spill Recovery: Mechanical Properties under Fatigue Conditions and Selective Absorption in Oil/Water Mixtures.

Marine pollution due to spillage of hydrocarbons represents a well-known current environmental problem. In order to recover the otherwise wasted oils and to prevent pollution damage, polyurethane foams are considered suitable materials for their ability to separate oils from sea-water and for their reusability. In this work we studied polyurethane foams filled with carbon nanofibers, in varying amounts, aimed at enhancing the selectivity of the material towards the oils and at improving the mechanical durability of the foam. Polyurethane-based foams were experimentally characterized by morphological, surface, and mechanical analyses (optical microscopy observation, contact angle measurement, absorption test according to ASTM F726-99 standard and compression fatigue tests according to ISO 24999 standard). Results indicated an increase in hydrophobic behavior and a good oleophilic character of the composite sponges besides an improved selective absorption of the foam toward oils in mixed water/oil media. The optimal filler amount was found to be around 1 wt% for the homogeneous distribution inside the polymeric foam. Finally, the fatigue test results showed an improvement of the mechanical properties of the foam with the growing carbon filler amount.

Mechanical, Wear and Thermal Behavior of Polyethylene Blended with Graphite Treated in Ball Milling.

Additive manufacturing, civil, and biomechanical applications are among the most important sectors, where the filler's presence can significantly improve the quality of polymeric products blends. The high market demand of new low-cost material to be used as shock absorbers and mechanical joints arouses our curiosity to study a relatively common commercial polymer and filler. The possible improvement by blending high-density polyethylene (HDPE) and graphite was investigated for these sectors. To achieve this objective, we have prepared HDPE/graphite nanocomposites following mechanical treatment to understand which parameter provides the researched properties. As widely reported in the literature, milling treatment leads to the decrease of the particle size and the exfoliation of graphitic layers. Therefore, graphite has been previously treated with a ball mill for different times (1-16 h) to enhance its lubricating action. We checked an improvement in stiffness, yielding strength, thermal stability, and, in particularly, wear resistance that increased by 65% with respect to that of polyethylene (PE). A treatment time of eight hours in ball milling could be enough to give an appreciable improvement. The wear behavior of HDPE with treated graphite has not been deeply investigated so far, and it could be important because HDPE is considered a "carrier polymer" for different low-friction applications.

Chitosan/PAMAM/Hydroxyapatite Engineered Drug Release Hydrogels with Tunable Rheological Properties.

In this paper, a new formulation of biodegradable and bioresorbable chitosan-based hydrogel for controlled drug release was investigated. A chitosan-dendrimer-hydroxyapatite hydrogel, obtained by covalently grafting chitosan powder with an hyperbranched PAMAM dendrimer followed by in-situ precipitation of hydroxyapatite and gelification, was synthesized and characterized by FTIR, NMR, TGA, XRD and rheological studies. The hydrogels have been also doped with an anti-inflammatory drug (ketoprofen) in order to investigate their drug release properties. Chemical and chemical-physical characterizations confirmed the successful covalent functionalization of chitosan with PAMAM and the synthesis of nanostructured hydroxyapatite. The developed hydrogel made it possible to obtain an innovative system with tunable rheological and drug-releasing properties relative to the well-known formulation containing chitosan and hydroxyapatite powder. The developed hydrogel showed different rheological and drug-releasing properties of chitosan matrix mixed with hydroxyapatite as a function of dendrimer molecular weight; therefore, the chitosan-dendrimer-hydroxyapatite hydrogel can couple the well-known osteoconductive properties of hydroxyapatite with the drug-release behavior and good processability of chitosan-dendrimer hydrogels, opening new approaches in the field of tissue engineering based on biopolymeric scaffolds.

Functionalized polyhedral oligosilsesquioxane (POSS) based composites for bone tissue engineering: synthesis, computational and biological studies.

Functionalized polyhedral oligosilsesquioxanes (POSS) containing an isoxazolidine nucleus have been synthesized by microwave assisted 1,3-dipolar cycloaddition of N-methyl-C-alkoxycarbonyl nitrone 1 with POSS containing olefin moieties. The results of cycloaddition processes were rationalized by computational studies at the DFT level. The covalent conjugation of chitosan with the cycloadduct 3a leads to composite material CS-POSS 7 which was gelified using genipin as cross linking agent. The suitability of the system for bone tissue engineering purposes was evaluated by in vitro drug release studies using ketoprofen as a model drug and cytotoxicity assays performed on human fetal osteoblastic cells. The preliminary biological tests showed the lack of cytotoxicity of the hybrid material and suggest its potential role in bone tissue engineering applications.

Engineering of Chitosan-Hydroxyapatite-Magnetite Hierarchical Scaffolds for Guided Bone Growth.

Bioabsorbable materials have received increasing attention as innovative systems for the development of osteoconductive biomaterials for bone tissue engineering. In this paper, chitosan-based composites were synthesized adding hydroxyapatite and/or magnetite in a chitosan matrix by in situ precipitation technique. Composites were characterized by optical and electron microscopy, thermogravimetric analyses (TGA), x-ray diffraction (XRD), and in vitro cell culture studies. Hydroxyapatite and magnetite were found to be homogeneously dispersed in the chitosan matrix and the composites showed superior biocompatibility and the ability to support cell attachment and proliferation; in particular, the chitosan/hydroxyapatite/magnetite composite (CS/HA/MGN) demonstrated superior bioactivity with respect to pure chitosan (CS) and to the chitosan/hydroxyapatite (CS/HA) scaffolds.

Mitochondrial Impairment Induced by Sub-Chronic Exposure to Multi-Walled Carbon Nanotubes.

Human exposure to carbon nanotubes (CNTs) can cause health issues due to their chemical-physical features and biological interactions. These nanostructures cause oxidative stress, also due to endogenous reactive oxygen species (ROS) production, which increases following mitochondrial impairment. The aim of this in vitro study was to assess the health effects, due to mitochondrial dysfunction, caused by a sub-chronic exposure to a non-acutely toxic dose of multi walled CNTs (raw and functionalised). The A549 cells were exposed to multi-walled carbon nanotubes (MWCNTs) (2 µg mL-1) for 36 days. Periodically, cellular dehydrogenases, pyruvate dehydrogenase kinase 1 (PDK1), cytochrome c release, permeability transition pore (mPTP) opening, transmembrane potential (Δψ m), apoptotic cells, and intracellular ROS were measured. The results, compared to untreated cells and to positive control formed by cells treated with MWCNTs (20 µg mL-1), highlighted the efficiency of homeostasis to counteract ROS overproduction, but a restitutio ad integrum of mitochondrial functionality was not observed. Despite the tendency to restore, the mitochondrial impairment persisted. Overall, the results underlined the tissue damage that can arise following sub-chronic exposure to MWCNTs.

A Smart Nanovector for Cancer Targeted Drug Delivery Based on Graphene Quantum Dots.

Graphene quantum dots (GQD), the new generation members of graphene-family, have shown promising applications in anticancer therapy. In this study, we report the synthesis of a fluorescent and biocompatible nanovector, based on GQD, for the targeted delivery of an anticancer drug with benzofuran structure (BFG) and bearing the targeting ligand riboflavin (RF, vitamin B2). The highly water-dispersible nanoparticles, synthesized from multi-walled carbon nanotubes (MWCNT) by prolonged acidic treatment, were linked covalently to the drug by means of a cleavable PEG linker while the targeting ligand RF was conjugated to the GQD by π⁻π interaction using a pyrene linker. The cytotoxic effect of the synthesized drug delivery system (DDS) GQD-PEG-BFG@Pyr-RF was tested on three cancer cell lines and this effect was compared with that exerted by the same nanovector lacking the RF ligand (GQD-PEG-BFG) or the anticancer drug (GQD@Pyr-RF). The results of biological tests underlined the low cytotoxicity of the GQD sample and the cytotoxic activity of the DDS against the investigated cancer cell lines with a higher or similar potency to that exerted by the BFG alone, thus opening new possibilities for the use of this drug or other anticancer agents endowed of cytotoxicity and serious side effects.

Synthesis, identification and quantification of oligomers from polyester coatings for metal packaging.

Polyester can coatings protect both food and packaging from mutual contamination. Even though, can coatings may release Non-Intentionally Added Substances (NIAS) in addition to Intentionally Added Substances (IAS). As NIAS are mainly constituted by cyclic or linear side products that are formed during the polymerization process, we focused our attention on these oligomeric species of molecular weight <1000 Da. These oligomers were obtained from two different polyester resins, each synthesized from four monomers (two phthalic acids and two diols), and from the corresponding final enamel can coatings using ethanol at 95% and 50% at 60 °C for 4 h and 10 days, respectively, as food simulants. HPLC-ESI-MS analysis on the extracts allowed identifying various cyclic and linear oligomers. For the conclusive identification of the different oligomers and their isomeric structures, ad hoc standards were synthesized by acylation reaction between alkyl diols and phthaloyl chlorides. By comparison of 1H NMR spectra, linear and cyclic oligomers were characterized by finding the major presence of 2 + 2 cyclic compounds. The 16 synthesized standards, 4 linear and 12 cyclic compounds were used to establish a method for quantification of linear and cyclic oligomers in enamel migration samples by micro HPLC-high-resolution MS (HRMS). The results showed no significant differences between the amounts of cyclic oligomers extracted with both ethanol concentrations (50 and 95%) and time contact. The extracts showed only a small amount of linear compounds and a prevalence of 2 + 2 cyclic oligomers. The work shows the great importance of the synthesis of specific standards to allow exact quantification in food contact material migrates.

Graphene quantum dots: multifunctional nanoplatforms for anticancer therapy.

Graphene quantum dots, the next generation carbon based nanomaterials, due to their outstanding physical, chemical and biological properties, have shown potential in revolutionizing the future of nanomedicine and biotechnology. Their strong size-dependent photoluminescence (PL) and the presence of reactive groups on the GQD surface, which allow their multimodal conjugation with various functional groups and biologically active molecules, make them ideal candidates for cancer diagnosis and treatment. GQDs have been loaded with drugs and labeled with tumor-targeting ligand units that are able to specifically recognize cancer receptors exposed on the cancer cell surface by generating new therapies that are able to allow a more efficient targeted delivery of anticancer agents while minimizing their distribution in healthy tissues, as well as the development of new imaging agents for the in vitro and in vivo diagnosis of several types of cancer. Here, we review the recent advances in the study of the application of GQDs as nanoplatforms for anticancer therapy, taking into account the methods used for their synthesis and functionalization procedures, which can deeply affect their biocompatibility and their electronic and optical features. The biosafety and toxicity aspects of these nanomaterials at cellular and animal levels, mainly related to their size and the kind and degree of surface functionalization, are also discussed.

Effect of Ethyl Ester L-Lysine Triisocyanate addition to produce reactive PLA/PCL bio-polyester blends for biomedical applications.

We report in this paper the effects of Ethyl Ester L-Lysine Triisocyanate (LTI) on the physical-mechanical properties of Poly(lactide)/Poly(ε-caprolactone) (PLA/PCL) polyesters blends. The PLA/PCL ratios considered were 20/80, 50/50 and 80/20 (wt/wt %) and LTI was added in amounts of 0.0-0.5-1.0 phr. PLA and PCL reacted with LTI during processing in a Brabender twin screw internal mixer to produce block copolymers in-situ. The resulting blends have been characterized by torque measurements, uniaxial tensile tests, Differential Scanning Calorimeter, contact angle measurements with a Phosphate Buffered Saline (PBS) solution, ATR analysis and morphological SEM observations. Experimental results highlighted how LTI enhanced interaction and dispersion of the two components, resulting into a synergic effect in mechanical properties. Mechanical and physical properties can be tailored by changing the blend composition. The most noticeable trend was an increase in ductility of the mixed polymers. Besides, LTI decreased blend's wet ability in PBS and lowered the starting of crystalline phase formation for both polymers, confirming an interaction among them. These reactive blends could find use as biomedical materials, e.g. absorbable suture threads or scaffolds for cellular growth.

The role of the iron catalyst in the toxicity of multi-walled carbon nanotubes (MWCNTs).

This study aimed to investigate the role of iron, used as a catalyst, in the biological response to pristine and functionalized multi-walled carbon nanotubes (p/fMWCNTs) with an iron content of 2.5-2.8%. Preliminarily, we assessed the pro-oxidant activity of MWCNTs-associated iron by an abiotic test. To evaluate iron bioavailability, we measured intracellular redox-active iron in A549 cells exposed to both MWCNT suspensions and to the cell medium preconditioned by MWCNTs, in order to assess the iron dissolution rate under physiological conditions. Moreover, in exposed cells, we detected ROS levels, 8-oxo-dG and mitochondrial function. The results clearly highlighted that MWCNTs- associated iron was not redox-active and that iron leakage did not occur under physiological conditions, including the oxidative burst of specialized cells. Despite this, in MWCNTs exposed cells, higher level of intracellular redox-active iron was measured in comparison to control and a significant time-dependent ROS increase was observed (P<0.01). Higher levels of 8-oxo-dG, a marker of oxidative DNA damage, and decreased mitochondrial function, confirmed the oxidative stress induced by MWCNTs. Based on the results we believe that oxidative damage could be attributable to the release of endogenous redox-active iron. This was due to the damage of acidic vacuolar compartment caused by endocytosis-mediated MWCNT internalization.