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Amphibole asbestos is related to lung fibrosis and several types of lung tumors. The disease-triggering mechanisms still challenge our diagnostic capabilities and are still far from being fully understood. The literature focuses primarily on the role and formation of asbestos bodies in lung tissues, but there is a distinct lack of studies on amphibole particles that have been internalized by alveolar epithelial cells (AECs). These internalized particles may directly interact with the cell nucleus and the organelles, exerting a synergistic action with asbestos bodies (AB) from a different location. Here we document the near-atomic- to nano-scale transformations induced by, and taking place within, AECs of three distinct amphiboles (anthophyllite, grunerite, "amosite") with different Fe-content and morphologic features. We show that: (i) an Fe-rich layer is formed on the internalized particles, (ii) particle grain boundaries are transformed abiotically by the internal chemical environment of AECs and/or by a biologically induced mineralization mechanism, (iii) the Fe-rich material produced on the particle surface does not contain large amounts of P, in stark contrast to extracellular ABs, and (iv) the iron in the Fe-rich layer is derived from the particle itself. Internalized particles and ABs follow two distinct formation mechanisms reaching different physicochemical end-states., (© 2022. The Author(s).)

The synthesis of hydrophilic graphene-based yolk-shell magnetic nanoparticles functionalized with copolymer pluronic F-127 (GYSMNP@PF127) is herein reported to achieve an efficient multifunctional biomedical system for mild hyperthermia and stimuli-responsive drug delivery . In vitro tests revealed the extraordinary ability of GYSMNP@PF127 to act as smart stimuli-responsive multifunctional nanomedicine platform for cancer therapy, exhibiting (i) an outstanding loading capacity of 91% (w/w, representing 910 μg mg -1 ) of the chemotherapeutic drug doxorubicin, (ii) a high heating efficiency under an alternating (AC) magnetic field (intrinsic power loss ranging from 2.1-2.7 nHm 2  kg -1 ), and (iii) a dual pH and thermal stimuli-responsive drug controlled release (46% at acidic tumour pH vs 7% at physiological pH) under AC magnetic field, in just 30 min. Additionally, GYSMNP@PF127 presents optimal hydrodynamic diameter (D H  = 180 nm) with negative surface charge, high haemocompatibility for blood stream applications and tumour cellular uptake of drug nanocarriers. Due to its physicochemical, magnetic and biocompatibility properties, the developed graphene-based magnetic nanocarrier shows high promise as dual exogenous (AC field)/endogenous (pH) stimuli-responsive actuators for targeted thermo-chemotherapy, combining magnetic hyperthermia and controlled drug release triggered by the abnormal tumour environment. The presented strategy and findings can represent a new way to design and develop highly stable added-value graphene-based nanostructures for the combined treatment of cancer., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Novel nanoparticles containing non-stick coatings have been developed for food contact applications such as frying pans. Possible release of nanoparticles from such coatings into food is not known. In this paper, the characterisation of commercially available non-stick coatings was performed by use of FTIR, electron and optical microscopy, EDXS and XRD analysis. Characterisation revealed that the coatings contained micron- and nanosized rutile TiO 2 particles, and quartz SiO 2 embedded in a silicone polymer matrix. In order to estimate possible migration of TiO 2 nanoparticles from coatings into food, migration tests into simulants (deionised water, 3% acetic acid and 5 g l -1 citric acid) were performed (2 h at 100°C), and thermal and mechanical degradation of the matrix was studied. Simulants were analysed by ICP-MS after ultrafiltration and by microwave-assisted digestion. The concentration of titanium-containing particles that migrated into simulants was up to 861 µg l -1 (147 µg dm - 2 nanoparticles in 3% acetic acid was confirmed by SEM-EDXS analysis. Thermal stability study (TG/DSC MS analysis) did not show degradation of the matrix under foreseeable conditions of use, but mechanical degradation studies (scratch and tribological testing) showed possible release (microgram quantities per punched sample) of titanium-containing nanoparticles. The matrix degradation results were confirmed by observations of the morphology of the same type of coatings actually used for food preparation. Dissolution from the surface and matrix degradation can both contribute to nanoparticles release from this type of non-stick food contact coatings.2 nanoparticles in 3% acetic acid was confirmed by SEM-EDXS analysis. Thermal stability study (TG/DSC MS analysis) did not show degradation of the matrix under foreseeable conditions of use, but mechanical degradation studies (scratch and tribological testing) showed possible release (microgram quantities per punched sample) of titanium-containing nanoparticles. The matrix degradation results were confirmed by observations of the morphology of the same type of coatings actually used for food preparation. Dissolution from the surface and matrix degradation can both contribute to nanoparticles release from this type of non-stick food contact coatings.

With the advancement of drug delivery systems based on mesoporous silica nanoparticles (MSNs), a simple and efficient method regulating the drug release kinetics is needed. We developed redox-responsive release systems with three levels of hindrance around the disulfide bond. A model drug (rhodamine B dye) was loaded into MSNs' mesoporous voids. The pore opening was capped with β-cyclodextrin in order to prevent leakage of drug. Indeed, in absence of a reducing agent the systems exhibited little leakage, while the addition of dithiothreitol cleaved the disulfide bonds and enabled the release of cargo. The release rate and the amount of released dye were tuned by the level of hindrance around disulfide bonds, with the increased hindrance causing a decrease in the release rate as well as in the amount of released drug. Thus, we demonstrated the ability of the present mesoporous systems to intrinsically control the release rate and the amount of the released cargo by only minor structural variations. Furthermore, an in vivo experiment on zebrafish confirmed that the present model delivery system is nonteratogenic.

Amphibole asbestos is related to multiple diseases, mainly those targeting the lungs. Asbestos-related malignancies can also be caused by non-regulated asbestiform minerals and some elongated mineral particles (EMPs). In particular, the role of nano- and micro-sized EMPs internalized by lung epithelial cells must be clarified. This is of major importance when considering that EMPs to which humans are exposed are likely a highly heterogeneous mix of different mineral types, shapes, and sizes. Here, we document that particles smaller than 4.54 µm in length and smaller than 0.89 µm in width (e.g., particles that do not fit the regulatory categories to be identified as asbestos) are easily internalized because of their specific dimensions, surface charge, and shape (mostly dictated by the aspect ratio L/w). Once internalized, these particles can be found in proximity to the cell nucleus, in vesicles, and in the cytoplasm. Examining the localization of particles in cells provides important information, which helps in determining the physicochemical environment found inside the biological compartment, thus allowing for a better comprehension of the mineralogical transformation that might happen after internalization by cells. [ABSTRACT FROM AUTHOR]

Bacterial infections acquired in healthcare facilities including hospitals, the so called healthcare acquired or nosocomial infections, are still of great concern worldwide and represent a significant economical burden. One of the major causes of morbidity is infection with Methicillin Resistant Staphylococcus aureus (MRSA), which has been reported to survive on surfaces for several months. Bactericidal activity of copper-TiO2 thin films, which release copper ions and are deposited on glass surfaces and heated to high temperatures, is well known even when illuminated with very weak UVA light of about 10 μW/cm2. Lately, there is an increased intrerest for one-dimensional TiO2 nanomaterials, due to their unique properties, low cost, and high thermal and photochemical stability. Here we show that copper doped TiO2 nanotubes produce about five times more ·OH radicals as compared to undoped TiO2 nanotubes and that effective surface disinfection, determined by a modified ISO 22196:2011 test, can be achieved even at low intensity UVA light of 30 μW/cm2. The nanotubes can be deposited on a preformed surface at room temperature, resulting in a stable deposition resistant to multiple washings. Up to 103 microorganisms per cm2 can be inactivated in 24 hours, including resistant strains such as Methicillin-resistant Staphylococcus aureus (MRSA) and Extended-spectrum beta-lactamase Escherichia coli (E. coli ESBL). This disinfection method could provide a valuable alternative to the current surface disinfection methods. [ABSTRACT FROM AUTHOR]

Abstract: The solvothermal synthesis of ZnO particles from zinc acetylacetonate [Zn(acac)2] in the presence of monoethanolamine (MEA) or triethanolamine (TEA) at 170 °C is reported. The structural, optical and morphological characteristics of ZnO particles have been studied by X‐ray diffraction, UV‐Vis spectroscopy, FE‐SEM and TEM/STEM microscopy. The experimental findings are confirmed by means of DFT calculations. On the basis of the results, both experimental and theoretical, the growth mechanism is proposed which initiated the ZnO nucleation process continued by the growth of primary nanoparticles and immediately thereafter the spherical aggregation of ZnO particles. The calculations suggest that the process of ZnO nucleation proceeded mainly through the reaction of small dimers rather than oligomeric or monomeric species. The high chelating efficiency of both ethanolamines towards zinc with tetrahedral geometry is observed, having the same structural motif for the most stable ZnO–MEA and ZnO–TEA dimers. It was found that the way of primary ZnO nanoparticles growth and their spherical aggregation into final particles strongly depend on the type of ethanolamine used and the molar ratio [ethanolamine]/[Zn(acac)2]. The results show that the increase in TEA concentration could potentiate TEA coating on ZnO nanoparticles, which induced the formation of bigger, densely packed spherical aggregates. The reduced band gap energies were noticed with the increased sample microsphere size. [ABSTRACT FROM AUTHOR]

In this investigation we analyze an unprecedented difference in the behavior of nanoparticles when compared to the corresponding bulk. We have found that a chemical substitution can have the opposite effect on the magnetic properties of nanoparticles compared to the bulk, as revealed for the first time in the case of Sc-substituted barium-hexaferrite nanoplatelets. Even though the Sc substitution is known to greatly decrease the saturation magnetization, M S , of the bulk barium hexaferrite, it showed the opposite effect for nanoplatelets. The M S values of the nanoplatelets (in average 50 nm wide and approximately 3 nm thick) increased to over 38 Am2/kg, compared to ∼16 Am2/kg for unsubstituted nanoplatelets of comparable average size. The Sc incorporation was investigated with a combination of atomic-resolution imaging and elemental mappings in a scanning-transmission electron microscope. As in the bulk, the Sc3+ ions showed a clear preference for incorporation into an R block of the hexaferrite SRS∗R∗ structure for the nanoplatelets (R and S represent a hexagonal (BaFe 6 O 11)2- and a cubic (Fe 6 O 8)2+ structural block, respectively). A clear difference between the nano and the bulk observed for the first time was in the partial substitution of the Sc3+ for the Ba2+ in the nanoplatelets; however, this cannot explain the large increase in M S. Ab-initio calculations suggest that the opposite effect of the Sc substitution in the nanoplatelets to that in the bulk can be ascribed to specific, two-dimensional magnetic ordering in the platelets. Image 1 [ABSTRACT FROM AUTHOR]

δ-FeOOH is a synthetic analogue of a relatively uncommon mineral feroxyhyte (δ′-FeOOH). The conventional syntheses of δ-FeOOH start from the Fe(II) salt and proceed by a rapid oxidation of iron(II) hydroxide with H 2 O 2 . The new synthesis route to δ-FeOOH nanodiscs reported in this work is based on the γ -irradiation of a deoxygenated iron(III) chloride alkaline aqueous colloidal solution in the presence of 2-propanol and diethylaminoethyl-dextran hydrochloride (DEAE-dextran). γ -irradiation of the colloidal solution enabled the strong reducing conditions thus favouring the reduction of Fe(III) to Fe(II). Under such strong reducing conditions the white suspension characteristic of Fe(OH) 2 was formed. When the white suspension came into contact with oxygen from air it rapidly oxidized into stable green-gray suspension characteristic of Fe(II)-Fe(III) hydrochloride known as Green Rust I. In the conventional process of sample isolation the green-gray stable suspension transformed to δ-FeOOH reddish powder that consists of rather uniform regular nanodiscs. The synthesized δ-FeOOH nanodiscs are magnetic and contain a magnetically ordered component in the Mössbauer spectrum at room temperature. It is expected that the results of this work will have a strong impact on finding new synthetic routes to the δ-FeOOH. [ABSTRACT FROM AUTHOR]

The solvothermal synthesis of ZnO particles from zinc acetylacetonate [Zn(acac) 2 ] in the presence of triethanolamine (TEA) and various solvent systems at 170 °C is reported. The structural, optical and morphological characteristics of ZnO particles were investigated. It was found that the size and shape of ZnO nanoparticles and the way of their aggregation depend on the mole ratio [TEA]/[Zn(acac) 2 ] and the type of alcohol used as a solvent. Doubling the molar ratio of TEA to Zn(acac) 2 in the presence of ethanol favoured the formation of huge spherical aggregates (>3 μm) assembled from fine and uniform ZnO nanoparticles (∼20 nm). The results of present investigation show a strong impact of surface interactions between the formed ZnO nanoparticles and the molecules of solvent and TEA on the way of growth and aggregation, which enables the control of their morphological properties. The results show that TEA serves as a link between primary ZnO nanoparticles to form spherical aggregates with a controllable diameter. The results of X-ray diffraction size-strain analysis indicate the presence of size anisotropy with bigger crystallites in the direction of the c-ax of the zincite lattice compared with the direction perpendicular to the c-ax. The red shift of the absorption edge and reduced band gap energies are clearly visible with the increased sample microsphere size. [ABSTRACT FROM AUTHOR]

A model organic pigment (diketopyrrolopyrrole) is encapsulated by a silica coating in order to improve its photochemical stability. Unlike in previous works where single-layer silica coatings were used for similar purposes, we here propose creation of a multi-layer silica shell synthesized via in-situ sol-gel method, which should significantly improve the homogeneity and thus the protection ability of the coating. This is done by repeating the basic two-step process (pigment surface modification and silica encapsulation) several times, creating the final protective shell in a layer-by-layer fashion. The compositional and structural properties of the prepared coatings is studied using Fourier-transform infrared spectroscopy, differential thermal and thermogravimetric analysis, nitrogen adsorption measurements and transmission electron microscopy. Photochemical stability of non-encapsulated and encapsulated pigment particles is evaluated via the so-called fast-irradiation method. Various correlations between the essential coating properties, such as thickness, porosity, SiO 2 content, and the corresponding photochemical stability of the samples are established and discussed in detail. As a whole, our results confirm the basic hypothesis, that multiple-layered silica shells show improved pigment protection ability in comparison to the single-layer coatings. [ABSTRACT FROM AUTHOR]

Highlights: [•] Rutile nanoparticles were synthesized with low-temperature hydrothermal process. [•] 1-nm thick amorphous layer was observed on the surface of the particles. [•] The photocatalytic activity was evaluated with the degradation of caffeine. [•] Synthesized rutile particles showed superior activity than commercial rutile particles. [Copyright &y& Elsevier]

Abstract: Carbon xerogels synthesized from polycondensation of resorcinol with formaldehyde, having specific surface areas in the range 650 to 990m2 g−1 and variable degrees of surface oxidation, are used to prepare TiO2–carbon xerogel composites by sol–gel methods. These composite materials are used to support Pt nanoparticles (5wt.%) by the photodeposition technique. After a high temperature reduction treatment at 773K, the obtained materials were characterized in order to assess the interactions between the phases Pt, TiO2 and carbon xerogel. It is observed that the carbon xerogel acts as an adhesive agent of the TiO2 and Pt particles, enhancing the interaction between the metal and the composite support. [Copyright &y& Elsevier]