Publications by authors named "Gautom K Das"

Ambient ultrafine particulate matter (UPM), less than 100 nm in size, has been linked to the development and exacerbation of pulmonary diseases. Age differences in susceptibility to UPM may be due to a difference in delivered dose as well as age-dependent differences in lung biology and clearance. In this study, we developed and characterized aerosol exposures to novel metal oxide nanoparticles containing lanthanides to study particle deposition in the developing postnatal rat lung.

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The growing use of silver nanoparticles (AgNPs) in consumer products raises concerns about potential health effects. This study investigated the persistence and clearance of 2 different size AgNPs (20 and 110 nm) delivered to rats by single nose-only aerosol exposures (6 h) of 7.2 and 5.

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The contamination of drinking water with naturally occurring arsenic is a global health threat. Filters that are packed with adsorbent media with a high affinity for arsenic have been used to de-contaminate water - generally iron or aluminium oxides are favored materials. Recently, nanoparticles have been introduced as adsorbent media due to their superior efficiency compared to their bulk counter-parts.

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The current work reports a type of "smart" lanthanide-based theranostic nanoprobe, NaDyF4:Yb(3+)/NaGdF4:Yb(3+),Er(3+), which is able to circumvent the up-converting poisoning effect of Dy(3+) ions to give efficient near infrared (980 nm) triggered up-conversion fluorescence, and offers not only excellent dark T2-weighted MR contrast but also tunable bright and T1-weighted MR contrast properties. Due to the efficient up-converted energy transfer from the nanocrystals to chlorin e6 (Ce6) photosensitizers loaded onto the nanocrystals, cytotoxic singlet oxygen was generated and photodynamic therapy was demonstrated. Therefore, the current multifunctional nanocrystals could be potentially useful in various image-guided diagnoses where bright or dark MRI contrast could be selectively tuned to optimize image quality, but also as an efficient and more penetrative near-infrared activated photodynamic therapy agent.

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The cellular toxicity of nanoparticles that were capped with a bilayered ligand was studied using an up-converting (UC) phosphor material as a representative nanoparticle (NP). The results indicate that although UC NPs are known to be nontoxic, the toxicity of the NPs depends strongly on ligand coordination conditions, in addition to the other commonly known parameters such as size, structure, surface charge etc. Oleate-capped hydrophobic NaYF4:Yb,Er NPs were surface modified to yield three extreme conditions: bare particles that were stripped of the oleate ligands; particles with covalently bound poly(ethylene glycol) (PEG) ligands; and particles with an bilayer of PEG-oleate ligands using the oleate surface group that was remained after synthesis.

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X-ray luminescent nanoparticles (NPs), including lanthanide fluorides, have been evaluated for application to deep tissue in vivo molecular imaging using optical tomography. A combination of high material density, higher atomic number and efficient NIR luminescence from compatible lanthanide dopant ions indicates that particles that consist of ALnF (A = alkaline, Ln = lanthanide element) may offer a very attractive class of materials for high resolution, deep tissue imaging with X-ray excitation. NaGdF:Eu NPs produced an X-ray excited luminescence that was among the most efficient of nanomaterials that have been studied thus far.

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The increasing use of manufactured nanoparticles (NP) in different applications has triggered the need to understand their putative ecotoxicological effects in the environment. Copper oxide nanoparticles (CuO NP) are toxic, and induce oxidative stress and other pathophysiological conditions. The unique properties of NP can change depending on the characteristics of the media they are suspended in, altering the impact on their toxicity to aquatic organisms in different environments.

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The deposition, clearance and translocation of europium-doped gadolinium oxide nanoparticles in a mouse lung were investigated experimentally. Nanoparticles were synthesized by spray flame pyrolysis. The particle size, crystallinity and surface properties were characterized.

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Engineered nanomaterials have become prevalent in our everyday life. While the popularity of using nanomaterials in consumer products continues to rise, increasing awareness of nanotoxicology has also fuelled efforts to accelerate our understanding of the ill effects that different nanomaterials can bring to biological systems. In this study, we investigated the potential cytotoxicity and genotoxicity of three nanoparticles: titanium dioxide (TiO(2)), terbium-doped gadolinium oxide (Tb-Gd(2)O(3)), and poly(lactic-co-glycolic acid) (PLGA).

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A major limitation of the commonly used clinical MRI contrast agents (CAs) suitable at lower magnetic field strengths (<3.0 T) is their inefficiency at higher fields (>7 T), where next-generation MRI scanners are going. We present dysprosium nanoparticles (β-NaDyF4 NPs) as T2 CAs suitable at ultrahigh fields (9.

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Lanthanide nanomaterials are considered a less toxic alternative to quantum dots for bioimaging applications. This study evaluated the cytotoxicity of terbium (Tb)-doped gadolinium oxide (Gd(2)O(3)) and dysprosium oxide (Dy(2)O(3)) nanoparticles exposed to human (BEAS-2B) and mouse (L929) cell lines at a concentration range of 200-2000 μg/ml for 48 h. Two assay methods were utilized-WST-8 assay (colorimetric) based on mitochondrial metabolic activity and Pico-Green assay (fluorescence), which measures total DNA content.

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Fluorescent optical probes have been intensively used in the area of bio-imaging. In this review article, we describe the recent advancements in the synthesis and application of bimodal magnetic-fluorescent probes for bioimaging. The bimodal probes consist of fluorescent [semiconducting quantum dots (e.

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We demonstrate a simple synthetic strategy for the fabrication of single-phase rare earth (RE) doped gadolinium oxide (Gd(2)O(3):RE where RE = terbium (Tb), ytterbium (Yb), and erbium (Er)) nanorods (NRs) as multimodal imaging probes. The NRs are ultranarrow and exhibit both emission and magnetic characteristics. The Tb-doped and Yb/Er-codoped Gd(2)O(3) NRs exhibit down- and up-conversion fluorescence respectively, and also exhibit paramagnetism.

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The present study presents a new approach for evaluating in vitro cytotoxicity of nanoparticles. The approach is based on American National Standard ISO 10993-5. Hepatoma HepG2 and fibroblast NIH3T3 cell lines were incubated with nanoparticles, and their associated extracts were derived at 70 and 121 degrees C.

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