Carbon black and titanium dioxide nanoparticles elicit distinct apoptotic pathways in bronchial epithelial cells

<p>Abstract</p> <p>Background</p> <p>Increasing environmental and occupational exposures to nanoparticles (NPs) warrant deeper insight into the toxicological mechanisms induced by these materials. The present study was designed to characterize the cell death induced by carbon black (CB) and titanium dioxide (TiO₂) NPs in bronchial epithelial cells (16HBE14o- cell line and primary cells) and to investigate the implicated molecular pathways.</p> <p>Results</p> <p>Detailed time course studies revealed that both CB (13 nm) and TiO₂(15 nm) NP exposed cells exhibit typical morphological (decreased cell size, membrane blebbing, peripheral chromatin condensation, apoptotic body formation) and biochemical (caspase activation and DNA fragmentation) features of apoptotic cell death. A decrease in mitochondrial membrane potential, activation of Bax and release of cytochrome <it>c </it>from mitochondria were only observed in case of CB NPs whereas lipid peroxidation, lysosomal membrane destabilization and cathepsin B release were observed during the apoptotic process induced by TiO₂NPs. Furthermore, ROS production was observed after exposure to CB and TiO₂but hydrogen peroxide (H₂O₂) production was only involved in apoptosis induction by CB NPs.</p> <p>Conclusions</p> <p>Both CB and TiO₂NPs induce apoptotic cell death in bronchial epithelial cells. CB NPs induce apoptosis by a ROS dependent mitochondrial pathway whereas TiO₂NPs induce cell death through lysosomal membrane destabilization and lipid peroxidation. Although the final outcome is similar (apoptosis), the molecular pathways activated by NPs differ depending upon the chemical nature of the NPs.</p

Scale-up of continuous microcapsule production

status: publishe

Reducing the Induction Time Using Ultrasound and High-Shear Mixing in a Continuous Crystallization Process

© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Continuous crystallization in tubular crystallizers is of particular interest to the pharmaceutical industry to accurately control average particle size, particle size distribution, and (polymorphic) shape. However, these types of crystallizers require fast nucleation, and thus, short induction times at the beginning of the flow process, which is challenging for larger and complex organic molecules. High shear and/or the presence of bubbles were identified to influence the nucleation behavior. This work investigates the effects of both high-shear mixing and ultrasound on the anti-solvent crystallization of paracetamol in acetone–water. Both devices generate intense amounts of shear and gas bubbles. Generally, the results show that increasing input power decreases the induction time significantly for both the rotor–stator mixer and ultrasound probe. However, the induction time is almost independent of the supersaturation for the ultrasound probe, while the induction time significantly increases with decreasing supersaturation for the rotor–stator mixer. In contrast, the particle size distribution for the rotor–stator mixer is independent of the supersaturation, while increasing supersaturation decreases the particle size for the ultrasound probe.status: publishe

Development of a continuous reactor for emulsion-based microencapsulation of hexyl acetate with a polyuria shell

Microencapsulation is almost exclusively performed in batch processes. With today's chemistry increasingly performed in flow reactors, this work aims to realise a continuous reactor setup for the encapsulation of an ester with a polyuria (PU) shell. The generation of an emulsion template is performed in a recirculation loop driven by a pump and equipped with static mixers, screen type and Kenics((R)). Calorimetric measurements are performed to characterise the energy dissipation rate inside the loop. The curing step is performed in a coiled tube reactor with two geometric configurations. Number based capsule size distributions are derived from micrograph analysis. Results indicate that the recycle pump is the main contributor to determine the capsule size distribution. A continuous setup is achieved for PU microcapsules containing hexyl acetate with a production rate of 198g/h dry capsules, and a mean capsule diameter of 13.3 mu m with a core content of 54wt%

Development of a continuous reactor for emulsion-based microencapsulation of hexyl acetate with a polyuria shell

Microencapsulation is almost exclusively performed in batch processes. With today's chemistry increasingly performed in flow reactors, this work aims to realise a continuous reactor setup for the encapsulation of an ester with a polyuria (PU) shell. The generation of an emulsion template is performed in a recirculation loop driven by a pump and equipped with static mixers, screen type and Kenics®. Calorimetric measurements are performed to characterise the energy dissipation rate inside the loop. The curing step is performed in a coiled tube reactor with two geometric configurations. Number based capsule size distributions are derived from micrograph analysis. Results indicate that the recycle pump is the main contributor to determine the capsule size distribution. A continuous setup is achieved for PU microcapsules containing hexyl acetate with a production rate of 198 g/h dry capsules, and a mean capsule diameter of 13.3 µm with a core content of 54 wt%.status: publishe

Assessment of side-effects by Ludox TMA silica nanoparticles following a dietary exposure on the bumblebee Bombus terrestris

We assessed lethal and sublethal side-effects of Ludox TMA silica nanoparticles on a terrestrial pollinator, Bombus terrestris (Linnaeus), via a dietary exposure. Dynamic light scattering analysis confirmed that silica Ludox TMA nanoparticles remained in suspension in the drinking sugar water. Exposure of bumblebee microcolonies during 7 weeks to the different nanoparticle concentrations (high: 34, 170 and 340 mg/l and low: 34 and 340 mu g/l) did not cause worker mortality compared to the controls. Also no effect on the worker foraging behavior was observed after exposure to nanoparticles concentrations up to 340 mu g/l. In contrast, the high concentrations (>= 34 mg/l) resulted in a total loss of reproduction. Using histological analysis we confirmed severe midgut epithelial injury in intoxicated workers (>= 34 mg/l). Despite the fact that these concentrations are much higher than the predicted environmental concentrations, precaution is still needed as information regarding their fate in the terrestrial environment and their potency to bioaccumulate and biomagnificate is lacking

Investigation of the cytotoxicity of nanozeolites A and Y

Nanosized zeolite particles are important materials for many applications in the field of nanotechnology. The possible adverse effects of these nanomaterials on human health have been scarcely investigated and remain largely unknown. This study reports the synthesis of nanozeolites Y and A with particle sizes of 25-100 nm and adequate colloidal stability for in vitro cytotoxicity experiments. The cytotoxic response of macrophages, epithelial and endothelial cells to these nanocrystals was assessed by determining mitochondrial activity (MTT assay) and cell membrane integrity (LDH leakage assay). After 24 h of exposure, no significant cytotoxic activity was detected for nanozeolite doses up to 500 μg/ml. The addition of fetal calf serum to the cell culture medium during exposure did not significantly change this low response. The nanozeolites showed low toxicity compared with monodisperse amorphous silica nanoparticles of similar size (60 nm). These results may contribute to the application of safe nanozeolites for purposes such as medical imaging, sensing materials, low-k films and molecular separation processes.status: publishe