High Doses of Silica Nanoparticles Obtained by Microemulsion and Green Routes Compromise Human Alveolar Cells Morphology and Stiffness Differently

Among all the inorganic nanomaterials used in commercial products, industry, and medicine, the amorphous silica nanoparticles (SiO2 NPs) appeared to be often tolerated in living organisms. However, despite several toxicity studies, some concerns about the exposure to high doses of SiO2 NPs with different sizes were raised. Then, we used the microemulsion method to obtain stable SiO2 NPs having different sizes (110 nm, 50 nm, and 25 nm). In addition, a new one-pot green synthetic route using leaves extract of Laurus nobilis was performed, obtaining monodispersed ultrasmall SiO2 NPs without the use of dangerous chemicals. The NPs achieved by microemulsion were further functionalized with amino groups making the NPs surface positively charged. Then, high doses of SiO2 NPs (1 mg/mL and 3 mg/mL) achieved from the two routes, having different sizes and surface charges, were used to assess their impact on human alveolar cells (A549), being the best cell model mimicking the inhalation route. Cell viability and caspase-3 induction were analyzed as well as the cellular uptake, obtaining that the smallest (25 nm) and positive-charged NPs were more able to induce cytotoxicity, reaching values of about 60% of cell death. Surprisingly, cells incubated with green SiO2 NPs did not show strong toxicity, and 70% of them remained vital. This result was unusual for ultrasmall nanoobjects, generally highly toxic. The actin reorganization, nuclear morphology alteration, and cell membrane elasticity analyses confirmed the trend achieved from the biological assays. The obtained data demonstrate that the increase in cellular softness, i.e., the decrease in Young's modulus, could be associated with the smaller and positive NPs, recording values of about 3 kPa. On the contrary, green NPs triggered a slight decrease of stiffness values (c.a. 6 kPa) compared to the untreated cells (c.a. 8 kPa). As the softer cells were implicated in cancer progression and metastasization, this evidence strongly supported the idea of a link between the cell elasticity and physicochemical properties of NPs that, in turn, influenced the interaction with the cell membrane. Thus, the green SiO2 NPs compromised cells to a lesser extent than the other SiO2 NPs types. In this scenario, the elasticity evaluation could be an interesting tool to understand the toxicity of NPs with the aim of predicting some pathological phenomena associated with their exposure

Nanostructures for SERS in living cell

Surface-enhanced Raman spectroscopy (SERS) has received renewed interest in recent years in fields such as trace analysis, biorelated diagnosis, and living cell study. However, the interference of impurities left on the surface from the preparation process of substrates limits to some extent the application of SERS. In the present paper, we propose a method to prepare clean SERS substrates by a combined method of hydrothermal green synthesis and thermal treatment to obtain a clean and impurity-free surface for SERS measurements, suitable for cells growth. The goal of such activity was the study of the membrane proteome, with special attention to prion protein (PrPC), in its physiological ambient. SERS has been used to evidence the PrPC-Cu(II) interaction in a rat neuroblastoma cell line (B104), known to overexpress the cellular prion protein PrPC

High ordered biomineralization induced by carbon nanoparticles in the sea urchin Paracentrotus lividus

A surprising and unexpected biomineralization process was observed during toxicological assessment of carbon nanoparticles on Paracentrotus lividus (sea urchin) pluteus larvae. The larvae activate a process of defense against external material, by incorporating the nanoparticles into microstructures of aragonite similarly to pearl oysters. Aiming at a better understanding of this phenomenon, the larvae were exposed to increasing concentrations of carbon nanoparticles and the biomineralization products were analyzed by electron microscopy, x-ray diffraction and Raman spectroscopy. In order to evaluate the possible influence of Sp-CyP-1 expression on this biomineralization process by larvae, analyses of gene expression (Sp-CyP-1) and calcein labeling were performed. Overall, we report experimental evidence about the capability of carbon nanoparticles to induce an increment of Sp-CyP-1 expression with the consequent activation of a biomineralization process leading to the production of a new pearl-like biomaterial never previously observed in sea urchins

Cyto/Biocompatibility of Dopamine Combined with the Antioxidant Grape Seed-Derived Polyphenol Compounds in Solid Lipid Nanoparticles

none10The loss of nigrostriatal neurons containing dopamine (DA) together with the “mitochondrial dysfunction” in midbrain represent the two main causes related to the symptoms of Parkinson’s disease (PD). Hence, the aim of this investigation is to co-administer the missing DA and the antioxidant grape seed-derived proanthocyanidins (grape seed extract, GSE) in order to increase the levels of the neurotransmitter (which is unable to cross the Blood Brain Barrier) and reducing the oxidative stress (OS) related to PD, respectively. Methods: For this purpose, we chose Solid Lipid Nanoparticles (SLN), because they have been already proven to increase DA uptake in the brain. DA-SLN adsorbing GSE (GSE/DA-SLN) were formulated and subjected to physico-chemical characterization, and their cytocompatibility and protection against OS were examined. Results: GSE was found on SLN surface and release studies evidenced the efficiency of GSE in preventing DA autoxidation. Furthermore, SLN showed high mucoadhesive strength and were found not cytotoxic to both primary Olfactory Ensheathing and neuroblastoma SH-SY5Y cells by MTT test. Co-administration of GSE/DA-SLN and the OS-inducing neurotoxin 6-hydroxydopamine (100 μM) resulted in an increase of SH-SY5Y cell viability. Conclusions: Hence, SLN formulations containing DA and GSE may constitute interesting candidates for non-invasive nose-to-brain delivery.openAdriana Trapani, Lorenzo Guerra, Filomena Corbo, Stefano Castellani, Enrico Sanna, Loredana Capobianco, Anna Grazia Monteduro, Daniela Erminia Manno, Delia Mandracchia, Sante Di Gioia and Massimo ConeseTrapani, Adriana; Guerra, Lorenzo; Corbo, Filomena; Castellani, Stefano; Sanna, Enrico; Capobianco, Loredana; Monteduro, ANNA GRAZIA; Manno, Daniela Erminia; Mandracchia, Delia; Di Gioia and Massimo Conese, Sant

Synthesis and growth mechanism of dendritic Cu2−xSe microstructures

Dendritic crystalline copper selenides Cu2-xSe microstructures with various dimensions have been fabricated in large scale through thermal treatment of CuSe powder in argon flow, without any catalyst. The CuSe powder grains were used as both reagents and substrates for the growth of the Cu2-xSe dendrites. The synthesized microstructures were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, selected area diffraction pattern and Raman spectroscopy. Each individual dendrite was mainly composed of a long central trunk with secondary lateral branches. The length of the main trunk was in the range 10-30 mu m, the width of the secondary branch lay in the range 1-5 mu m. The trunk was about 1-2 mu m in diameter while the lateral branches were about 0.4-0.8 mu m in diameter. The lateral branches grew in parallel and kept about 60 degrees with respect to the central trunk. A possible growth mechanism has been also proposed to account the growth of these Cu2-xSe dendritic microstructures

Solid-to-solid phase transformations of nanostructured selenium-tin thin films induced by thermal annealing in oxygen atmosphere

The structural and morphological evolution of nanostructured thin films obtained from thermal evaporation of polycrystalline Sn-Se starting charge as a function of the subsequent annealing temperature in an oxygen flow has been analysed. High-resolution transmission electron microscopy, small area electron diffraction, digital image processing, x-ray diffraction and Raman spectroscopy have been employed in order to investigate the structure and the morphology of the obtained films. The results evidenced, in the temperature range from RT to 500°C, the transition of the material from a homogeneous mixture of SnSe and SnSe2 nanocrystals, towards a homogeneous mixture of SnO2 and SeO2 nanocrystals, with an intermediate stage in which only SnSe2 nanocrystals are present

Surface structural and morphological characterization of ZnTe epilayers grown on {100}GaAs by MOVPE

The surface structural and. morphological characterization of ZnTe epilayers grown on (100)GaAs by atmospheric pressure MOVPE is reported. Scanning electron microscopy (SEM), reflection high energy electron diffraction (RHEED) and reflection electron microscopy (REM) have been performed on the as-grown ZnTe epilayer surfaces. RHEED pattern allowed to estimate the ZnTe crystalline quality, whereas the layer-to-substrate epitaxial relationships have been demonstrated from both RHEED and X-ray diffraction. SEM and REM observations in combination with alpha-step surface profiling measurements allowed to obtain a quantitative description of ZnTe surface irregularities, whose dimensions range from a few nm to just above 30 nm in height, being several hundred nm wide across the surface. Also, the ZnTe surface roughness depends linearly on the epilayer thickness and approaches the initial surface roughness of the GaAs substrates when the thickness tends to zero. Finally, no evident surface anisotropy has been revealed in the present samples, apart from a characteristic [011] elongation effect of some growth defect features at the epilayer surfaces