The Experts below are selected from a list of 3651 Experts worldwide ranked by ideXlab platform
Diana S Aga - One of the best experts on this subject based on the ideXlab platform.
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investigating uptake of water dispersible cdse zns Quantum Dot Nanoparticles by arabidopsis thaliana plants
Journal of Hazardous Materials, 2012Co-Authors: Divina A Navarro, Mary A Bisson, Diana S AgaAbstract:Interest on the environmental impacts of engineered nanomaterials has rapidly increased over the past years because it is expected that these materials will eventually be released into the environment. The present work investigates the potential root uptake of water-dispersible CdSe/ZnS Quantum Dots (QDs) by the model plant species, Arabidopsis thaliana. Experiments revealed that Arabidopsis exposed to QDs that are dispersed in Hoagland's solution for 1–7 days did not internalize intact QDs. Analysis of Cd and Se concentrations in roots and leaves by inductively-coupled plasma mass spectrometry indicated that Cd and Se from QD-treated plants were not translocated into the leaves, and remained in the root system of Arabidopsis. Furthermore, fluorescence microscopy showed strong evidence that the QDs were generally on the outside surfaces of the roots, where the amount of QDs adsorbed is dependent on the stability of the QDs in suspension. Despite no evidence of nanoparticle internalization, the ratio of reduced glutathione levels (GSH) relative to the oxidized glutathione (GSSG) in plants decreased when plants were exposed to QD dispersions containing humic acids, suggesting that QDs caused oxidative stress on the plant at this condition.
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Investigating uptake of water-dispersible CdSe/ZnS Quantum Dot Nanoparticles by Arabidopsis thaliana plants.
Journal of hazardous materials, 2011Co-Authors: Divina A Navarro, Mary A Bisson, Diana S AgaAbstract:Interest on the environmental impacts of engineered nanomaterials has rapidly increased over the past years because it is expected that these materials will eventually be released into the environment. The present work investigates the potential root uptake of water-dispersible CdSe/ZnS Quantum Dots (QDs) by the model plant species, Arabidopsis thaliana. Experiments revealed that Arabidopsis exposed to QDs that are dispersed in Hoagland's solution for 1-7 days did not internalize intact QDs. Analysis of Cd and Se concentrations in roots and leaves by inductively-coupled plasma mass spectrometry indicated that Cd and Se from QD-treated plants were not translocated into the leaves, and remained in the root system of Arabidopsis. Furthermore, fluorescence microscopy showed strong evidence that the QDs were generally on the outside surfaces of the roots, where the amount of QDs adsorbed is dependent on the stability of the QDs in suspension. Despite no evidence of nanoparticle internalization, the ratio of reduced glutathione levels (GSH) relative to the oxidized glutathione (GSSG) in plants decreased when plants were exposed to QD dispersions containing humic acids, suggesting that QDs caused oxidative stress on the plant at this condition.
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study on the effects of humic and fulvic acids on Quantum Dot Nanoparticles using capillary electrophoresis with laser induced fluorescence detection
Environmental Science & Technology, 2011Co-Authors: Mary Dawn Celiz, Luis A Colon, David F Watson, Diana S AgaAbstract:The increasing production and use of Quantum Dot (QD) Nanoparticles have caused concerns on the possibility of contaminating the aquatic and terrestrial ecosystems with wastes that may contain QDs. Therefore, studies on the behavior of QDs upon interaction with components of the natural environment have become of interest. This study investigated the fluorescence and electrophoretic mobility of carboxylic or amine polyethylene glycol (PEG)-functionalized CdSe/ZnS QDs in the presence of two aquatic humic substances (HS), Suwannee River humic and fulvic acids, using capillary electrophoresis with laser-induced fluorescence detection. Results showed initial enhancement in fluorescence of QDs at the onset of the interaction with HS, followed by fluorescence quenching at longer exposure with HS (>30 min). It was also observed that the electrophoretic mobility of QDs increases with increasing concentration of HS, suggesting an increase in the ratio in charge to hydrodynamic size of the Nanoparticles. To determi...
Divina A Navarro - One of the best experts on this subject based on the ideXlab platform.
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investigating uptake of water dispersible cdse zns Quantum Dot Nanoparticles by arabidopsis thaliana plants
Journal of Hazardous Materials, 2012Co-Authors: Divina A Navarro, Mary A Bisson, Diana S AgaAbstract:Interest on the environmental impacts of engineered nanomaterials has rapidly increased over the past years because it is expected that these materials will eventually be released into the environment. The present work investigates the potential root uptake of water-dispersible CdSe/ZnS Quantum Dots (QDs) by the model plant species, Arabidopsis thaliana. Experiments revealed that Arabidopsis exposed to QDs that are dispersed in Hoagland's solution for 1–7 days did not internalize intact QDs. Analysis of Cd and Se concentrations in roots and leaves by inductively-coupled plasma mass spectrometry indicated that Cd and Se from QD-treated plants were not translocated into the leaves, and remained in the root system of Arabidopsis. Furthermore, fluorescence microscopy showed strong evidence that the QDs were generally on the outside surfaces of the roots, where the amount of QDs adsorbed is dependent on the stability of the QDs in suspension. Despite no evidence of nanoparticle internalization, the ratio of reduced glutathione levels (GSH) relative to the oxidized glutathione (GSSG) in plants decreased when plants were exposed to QD dispersions containing humic acids, suggesting that QDs caused oxidative stress on the plant at this condition.
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Investigating uptake of water-dispersible CdSe/ZnS Quantum Dot Nanoparticles by Arabidopsis thaliana plants.
Journal of hazardous materials, 2011Co-Authors: Divina A Navarro, Mary A Bisson, Diana S AgaAbstract:Interest on the environmental impacts of engineered nanomaterials has rapidly increased over the past years because it is expected that these materials will eventually be released into the environment. The present work investigates the potential root uptake of water-dispersible CdSe/ZnS Quantum Dots (QDs) by the model plant species, Arabidopsis thaliana. Experiments revealed that Arabidopsis exposed to QDs that are dispersed in Hoagland's solution for 1-7 days did not internalize intact QDs. Analysis of Cd and Se concentrations in roots and leaves by inductively-coupled plasma mass spectrometry indicated that Cd and Se from QD-treated plants were not translocated into the leaves, and remained in the root system of Arabidopsis. Furthermore, fluorescence microscopy showed strong evidence that the QDs were generally on the outside surfaces of the roots, where the amount of QDs adsorbed is dependent on the stability of the QDs in suspension. Despite no evidence of nanoparticle internalization, the ratio of reduced glutathione levels (GSH) relative to the oxidized glutathione (GSSG) in plants decreased when plants were exposed to QD dispersions containing humic acids, suggesting that QDs caused oxidative stress on the plant at this condition.
Nancy A. Monteiro-riviere - One of the best experts on this subject based on the ideXlab platform.
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Biological interactions of Quantum Dot Nanoparticles in skin and in human epidermal keratinocytes
Toxicology and applied pharmacology, 2008Co-Authors: Leshuai W. Zhang, Vicki L. Colvin, Nancy A. Monteiro-riviereAbstract:Quantum Dots Nanoparticles have novel optical properties for biomedical applications and electronics, but little is known about their skin permeability and interaction with cells. QD621 are nail-shaped Nanoparticles that contain a cadmium/selenide core with a cadmium sulfide shell coated with polyethylene glycol (PEG) and are soluble in water. QD were topically applied to porcine skin flow-through diffusion cells to assess penetration at 1 {mu}M, 2 {mu}M and 10 {mu}M for 24 h. QD were also studied in human epidermal keratinocytes (HEK) to determine cellular uptake, cytotoxicity and inflammatory potential. Confocal microscopy depicted the penetration of QD621 through the uppermost stratum corneum (SC) layers of the epidermis and fluorescence was found primarily in the SC and near hair follicles. QD were found in the intercellular lipid bilayers of the SC by transmission electron microscopy (TEM). Inductively coupled plasma-optical emission spectroscopy (ICP-OES) analysis for cadmium (Cd) and fluorescence for QD both did not detect Cd nor fluorescence signal in the perfusate at any time point or concentration. In HEK, viability decreased significantly (p < 0.05) from 1.25 nM to 10nM after 24 h and 48 h. There was a significant increase in IL-6 at 1.25 nM to 10 nM, while IL-8 increasedmore » from 2.5nM to 10nM after 24 h and 48 h. TEM of HEK treated with 10 nM of QD621 at 24 h depicted QD in cytoplasmic vacuoles and at the periphery of the cell membranes. These results indicate that porcine skin penetration of QD621 is minimal and limited primarily to the outer SC layers, yet if the skin were damaged allowing direct QD exposure to skin or keratinocytes, an inflammatory response could be initiated.« less
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Cyclic tensile strain increases interactions between human epidermal keratinocytes and Quantum Dot Nanoparticles
Toxicology in vitro : an international journal published in association with BIBRA, 2007Co-Authors: Jillian G. Rouse, Carla M. Haslauer, Elizabeth G. Loboa, Nancy A. Monteiro-riviereAbstract:The effects of Quantum Dots (QD) on cell viability have gained increasing interest due to many recent developments utilizing QD for pharmaceutical and biomedical applications. The potential use of QD Nanoparticles as diagnostic, imaging, and drug delivery agents has raised questions about their potential for cytotoxicity. The objective of this study was to investigate the effects of applied strain on QD uptake by human epidermal keratinocytes (HEK). It was hypothesized that introduction of a 10% average strain to cell cultures would increase QD uptake. HEK were seeded at a density of 150,000 cells/mL on collagen-coated Flexcell culture plates (Flexcell Intl.). QD were introduced at a concentration of 3 nM and a 10% average strain was applied to the cells. After 4 h of cyclic strain, the cells were examined for cell viability, QD uptake, and cytokine production. The results indicate that addition of strain results in an increase in cytokine production and QD uptake, resulting in irritation and a negative impact on cell viability. Application of physiological load conditions can increase cell membrane permeability, thereby increasing the concentration of QD Nanoparticles in cells.
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Biodistribution of Quantum Dot Nanoparticles in Perfused Skin: Evidence of Coating Dependency and Periodicity in Arterial Extraction
Nano letters, 2007Co-Authors: Hyun A. Lee, Vicki L. Colvin, Nancy A. Monteiro-riviere, Mudassar Imran, Jim E. RiviereAbstract:Arterial extraction of Quantum Dots (QD) assayed by fluorescence or inductively coupled plasma (ICP) emission spectrometry were studied after infusion into isolated perfused skin. Extraction was mathematically modeled using three linear differential equations. COOH-coated QD had greater tissue deposition, assessed both by model prediction and laser confocal scanning microscopy, than did QD-PEG. Both QD had a unique periodicity in arterial extraction never observed with drug infusions, suggesting a potentially important nanomaterial behavior that could affect systemic disposition.
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Variables influencing interactions of untargeted Quantum Dot Nanoparticles with skin cells and identification of biochemical modulators.
Nano letters, 2007Co-Authors: Jessica P. Ryman-rasmussen, Jim E. Riviere, Nancy A. Monteiro-riviereAbstract:Skin cells (NHEK) take up untargeted Quantum Dots (QD) with surface polyethylene glycol (PEG), amines, and carboxylic acids, but the mechanisms are unknown. Time courses of QD-NHEK interactions were determined and effects of QD surface coating, temperature, culture medium supplements and inhibitors of the cell cycle and endocytosis identified. The magnitude of QD-NHEK interactions was coating dependent. Low-temperature or unsupplemented medium decreased QD-NHEK interactions. Biochemical inhibitors were identified that attenuate and potentiate QD-NHEK interactions. These results are important for understanding and controlling interactions of untargeted QD with cells.
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Surface coatings determine cytotoxicity and irritation potential of Quantum Dot Nanoparticles in epidermal keratinocytes.
The Journal of investigative dermatology, 2006Co-Authors: Jessica P. Ryman-rasmussen, Jim E. Riviere, Nancy A. Monteiro-riviereAbstract:Quantum Dot (QD) Nanoparticles have potential applications in nanomedicine as drug delivery vectors and diagnostic agents, but the skin toxicity and irritation potential of QDs are unknown. Human epidermal keratinocytes (HEKs) were used to assess if QDs with different surface coatings would cause differential effects on HEK cytotoxicity, proinflammatory cytokine release, and cellular uptake. Commercially available QDs of two different sizes, QD 565 and QD 655, with neutral (polyethylene glycol (PEG)), cationic (PEG-amine), or anionic (carboxylic acid) coatings were utilized. Live cell imaging and transmission electron microscopy were used to determine that all QDs localized intracellularly by 24 hours, with evidence of QD localization in the nucleus. Cytotoxicity and release of the proinflammatory cytokines IL-1β, IL-6, IL-8, IL-10, and tumor necrosis factor-α were assessed at 24 and 48 hours. Cytotoxicity was observed for QD 565 and QD 655 coated with carboxylic acids or PEG-amine by 48 hours, with little cytotoxicity observed for PEG-coated QDs. Only carboxylic acid-coated QDs significantly increased release of IL-1β, IL-6, and IL-8. These data indicate that QD surface coating is a primary determinant of cytotoxicity and immunotoxicity in HEKs, which is consistent across size. However, uptake of QDs by HEKs is independent of surface coating.
Mary A Bisson - One of the best experts on this subject based on the ideXlab platform.
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investigating uptake of water dispersible cdse zns Quantum Dot Nanoparticles by arabidopsis thaliana plants
Journal of Hazardous Materials, 2012Co-Authors: Divina A Navarro, Mary A Bisson, Diana S AgaAbstract:Interest on the environmental impacts of engineered nanomaterials has rapidly increased over the past years because it is expected that these materials will eventually be released into the environment. The present work investigates the potential root uptake of water-dispersible CdSe/ZnS Quantum Dots (QDs) by the model plant species, Arabidopsis thaliana. Experiments revealed that Arabidopsis exposed to QDs that are dispersed in Hoagland's solution for 1–7 days did not internalize intact QDs. Analysis of Cd and Se concentrations in roots and leaves by inductively-coupled plasma mass spectrometry indicated that Cd and Se from QD-treated plants were not translocated into the leaves, and remained in the root system of Arabidopsis. Furthermore, fluorescence microscopy showed strong evidence that the QDs were generally on the outside surfaces of the roots, where the amount of QDs adsorbed is dependent on the stability of the QDs in suspension. Despite no evidence of nanoparticle internalization, the ratio of reduced glutathione levels (GSH) relative to the oxidized glutathione (GSSG) in plants decreased when plants were exposed to QD dispersions containing humic acids, suggesting that QDs caused oxidative stress on the plant at this condition.
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Investigating uptake of water-dispersible CdSe/ZnS Quantum Dot Nanoparticles by Arabidopsis thaliana plants.
Journal of hazardous materials, 2011Co-Authors: Divina A Navarro, Mary A Bisson, Diana S AgaAbstract:Interest on the environmental impacts of engineered nanomaterials has rapidly increased over the past years because it is expected that these materials will eventually be released into the environment. The present work investigates the potential root uptake of water-dispersible CdSe/ZnS Quantum Dots (QDs) by the model plant species, Arabidopsis thaliana. Experiments revealed that Arabidopsis exposed to QDs that are dispersed in Hoagland's solution for 1-7 days did not internalize intact QDs. Analysis of Cd and Se concentrations in roots and leaves by inductively-coupled plasma mass spectrometry indicated that Cd and Se from QD-treated plants were not translocated into the leaves, and remained in the root system of Arabidopsis. Furthermore, fluorescence microscopy showed strong evidence that the QDs were generally on the outside surfaces of the roots, where the amount of QDs adsorbed is dependent on the stability of the QDs in suspension. Despite no evidence of nanoparticle internalization, the ratio of reduced glutathione levels (GSH) relative to the oxidized glutathione (GSSG) in plants decreased when plants were exposed to QD dispersions containing humic acids, suggesting that QDs caused oxidative stress on the plant at this condition.
Sung-liang Chen - One of the best experts on this subject based on the ideXlab platform.
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Optomechanical Time-Gated Fluorescence Imaging Using Long-Lived Silicon Quantum Dot Nanoparticles
Analytical chemistry, 2019Co-Authors: Wenzhao Yang, Prateek K. Srivastava, Shanshan Han, Lili Jing, Sung-liang ChenAbstract:We demonstrate a novel optomechanical synchronization method to achieve ultrahigh-contrast time-gated fluorescence imaging using live zebrafish as models. Silicon Quantum Dot Nanoparticles (SiQDNPs) with photoluminescence lifetime of about 16 μs were used as the long-lived probes to enable background autofluorescence removal and multiplexing through time-gating. A continuous-wave 405 nm laser as the excitation source was focused on a rotating optical chopper on which the emission light beam obtained from an inverted fluorescence microscope was also focused but with a phase difference such that in a short delay after the excitation laser is blocked, the emission light beam passes through the optical chopper, initiating the image acquisition by a conventional sensor. Both excitation and detection time windows were synchronized by one optical chopper, eliminating the need for pulsed light source and image intensifier which is often used as ultrafast optical shutter. Through use of the cost-effective time-gat...
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Optomechanical Time-Gated Fluorescence Imaging Using Long-Lived Silicon Quantum Dot Nanoparticles
2019Co-Authors: Wenzhao Yang, Prateek K. Srivastava, Shanshan Han, Lili Jing, Sung-liang ChenAbstract:We demonstrate a novel optomechanical synchronization method to achieve ultrahigh-contrast time-gated fluorescence imaging using live zebrafish as models. Silicon Quantum Dot Nanoparticles (SiQDNPs) with photoluminescence lifetime of about 16 μs were used as the long-lived probes to enable background autofluorescence removal and multiplexing through time-gating. A continuous-wave 405 nm laser as the excitation source was focused on a rotating optical chopper on which the emission light beam obtained from an inverted fluorescence microscope was also focused but with a phase difference such that in a short delay after the excitation laser is blocked, the emission light beam passes through the optical chopper, initiating the image acquisition by a conventional sensor. Both excitation and detection time windows were synchronized by one optical chopper, eliminating the need for pulsed light source and image intensifier which is often used as ultrafast optical shutter. Through use of the cost-effective time-gating method, nearly all background autofluorescence emitted from the yolk sac of a zebrafish embryo microinjected with the SiQDNPs was removed, leading to a 45-fold increase in signal-to-background ratio. Furthermore, two kinds of fluorescence signals emitted from the microinjected SiQDNPs and the intrinsic green fluorescent protein of transgenic zebrafish larvae can be clearly separated through time-gating
