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Single-walled carbon nanotubes (SWCNT), nano-cylinders with an extremely small diameter (1-2 nm) and high aspect ratio, have unique physico-chemical, electronic and mechanical properties and may exhibit unusual interactions with cells and tissues, thus necessitating studies of their toxicity and health effects. Manufactured SWCNT usually contain significant(More)
Broad applications of single-walled carbon nanotubes (SWCNT) dictate the necessity to better understand their health effects. Poor recognition of non-functionalized SWCNT by phagocytes is prohibitive towards controlling their biological action. We report that SWCNT coating with a phospholipid "eat-me" signal, phosphatidylserine (PS), makes them recognizable(More)
Nanoparticulate barium sulfate has potential novel applications and wide use in the polymer and paint industries. A short-term inhalation study on barium sulfate nanoparticles (BaSO4 NPs) was previously published [Part Fibre Toxicol 11:16, 2014]. We performed comprehensive biokinetic studies of 131BaSO4 NPs administered via different routes and of acute and(More)
We have shown previously that single-walled carbon nanotubes can be catalytically biodegraded over several weeks by the plant-derived enzyme, horseradish peroxidase. However, whether peroxidase intermediates generated inside human cells or biofluids are involved in the biodegradation of carbon nanotubes has not been explored. Here, we show that hypochlorite(More)
MT1 melatonin receptors expressed in Chinese hamster ovary (CHO) cells remain sensitive to a melatonin re-challenge even following chronic melatonin exposure when microtubules are depolymerized in the cell, an exposure that normally results in MT1 receptor desensitization. We extended our findings to MT2 melatonin receptors using both in vitro and in vivo(More)
Advancement of biomedical applications of carbonaceous nanomaterials is hampered by their biopersistence and pro-inflammatory action in vivo. Here, we used myeloperoxidase knockout B6.129X1-MPO (MPO k/o) mice and showed that oxidation and clearance of single walled carbon nanotubes (SWCNT) from the lungs of these animals after pharyngeal aspiration was(More)
We show here the biodegradation of single-walled carbon nanotubes through natural, enzymatic catalysis. By incubating nanotubes with a natural horseradish peroxidase (HRP) and low concentrations of H2O2 (approximately 40 microM) at 4 degrees C over 12 weeks under static conditions, we show the increased degradation of nanotube structure. This reaction was(More)
Macrophage recognition of apoptotic cells depends on externalization of phosphatidylserine (PS), which is normally maintained within the cytosolic leaflet of the plasma membrane by aminophospholipid translocase (APLT). APLT is sensitive to redox modifications of its -SH groups. Because activated macrophages produce reactive oxygen and nitrogen species, we(More)
Nanoparticle pharmacokinetics and biological effects are influenced by several factors. We assessed the effects of amorphous SiO2 coating on the pharmacokinetics of zinc oxide nanoparticles (ZnO NPs) following intratracheal (IT) instillation and gavage in rats. Uncoated and SiO2-coated ZnO NPs were neutron-activated and IT-instilled at 1 mg/kg or gavaged at(More)
The physicochemical properties of nanoparticles (NPs) influence their biological outcomes. We assessed the effects of an amorphous silica coating on the pharmacokinetics and pulmonary effects of CeO2 NPs following intratracheal (IT) instillation, gavage and intravenous injection in rats. Uncoated and silica-coated CeO2 NPs were generated by flame spray(More)