The Experts below are selected from a list of 3081 Experts worldwide ranked by ideXlab platform
Christin M Grabinski - One of the best experts on this subject based on the ideXlab platform.
-
simulations of submicron aerosol deposition at an air liquid Interface for In Vitro Toxicology
Journal of Aerosol Science, 2015Co-Authors: Christin M Grabinski, Saber M Hussain, Mohan R SankaranAbstract:Abstract Submicron particles released durIng the lifecycle of nano-enabled products and as a byproduct of air pollution and occupational processes are a potential health risk. Recent advancements to In Vitro model systems have been proposed to assess the toxicity of particulate materials resultIng from Inhalation. The reliability of these models depends on the Introduction and deposition of aerosolized particles on cells at an air–liquid Interface. However, chamber geometry, gas flow rate, electric field, and other process parameters significantly impact how particles deposit at this Interface. Here, we carried out fInite element modelIng to describe the transport and deposition of submicron aerosolized particles. Simulations were performed usIng multiphysics software on a typical In Vitro exposure chamber design, and results were compared to analytical approximations for deposition efficiency. Deposition experiments were also systematically carried out to validate the modelIng predictions. Our results show how deposition depends on various process parameters. To achieve efficient deposition without focusIng, the electric field strength and gas flow rate must be balanced; at high gas flow rates, higher electric fields are required to achieve deposition. Further, we fInd that AC electric fields at the appropriate frequency can Increase deposition above DC fields at similar strengths. Overall, the study establishes simulation approaches for the design of In Vitro aerosol deposition chambers and relates key process parameters to deposition, which is critical to controllIng the dose of submicron aerosols In In Vitro Toxicology experiments.
-
Simulations of submicron aerosol deposition at an air–liquid Interface for In Vitro Toxicology
Journal of Aerosol Science, 2015Co-Authors: Christin M Grabinski, Saber M Hussain, R. Mohan SankaranAbstract:Submicron particles released durIng the lifecycle of nano-enabled products and as a byproduct of air pollution and occupational processes are a potential health risk. Recent advancements to In Vitro model systems have been proposed to assess the toxicity of particulate materials resultIng from Inhalation. The reliability of these models depends on the Introduction and deposition of aerosolized particles on cells at an air–liquid Interface. However, chamber geometry, gas flow rate, electric field, and other process parameters significantly impact how particles deposit at this Interface. Here, we carried out fInite element modelIng to describe the transport and deposition of submicron aerosolized particles. Simulations were performed usIng multiphysics software on a typical In Vitro exposure chamber design, and results were compared to analytical approximations for deposition efficiency. Deposition experiments were also systematically carried out to validate the modelIng predictions. Our results show how deposition depends on various process parameters. To achieve efficient deposition without focusIng, the electric field strength and gas flow rate must be balanced; at high gas flow rates, higher electric fields are required to achieve deposition. Further, we fInd that AC electric fields at the appropriate frequency can Increase deposition above DC fields at similar strengths. Overall, the study establishes simulation approaches for the design of In Vitro aerosol deposition chambers and relates key process parameters to deposition, which is critical to controllIng the dose of submicron aerosols In In Vitro Toxicology experiments.
Mohan R Sankaran - One of the best experts on this subject based on the ideXlab platform.
-
simulations of submicron aerosol deposition at an air liquid Interface for In Vitro Toxicology
Journal of Aerosol Science, 2015Co-Authors: Christin M Grabinski, Saber M Hussain, Mohan R SankaranAbstract:Abstract Submicron particles released durIng the lifecycle of nano-enabled products and as a byproduct of air pollution and occupational processes are a potential health risk. Recent advancements to In Vitro model systems have been proposed to assess the toxicity of particulate materials resultIng from Inhalation. The reliability of these models depends on the Introduction and deposition of aerosolized particles on cells at an air–liquid Interface. However, chamber geometry, gas flow rate, electric field, and other process parameters significantly impact how particles deposit at this Interface. Here, we carried out fInite element modelIng to describe the transport and deposition of submicron aerosolized particles. Simulations were performed usIng multiphysics software on a typical In Vitro exposure chamber design, and results were compared to analytical approximations for deposition efficiency. Deposition experiments were also systematically carried out to validate the modelIng predictions. Our results show how deposition depends on various process parameters. To achieve efficient deposition without focusIng, the electric field strength and gas flow rate must be balanced; at high gas flow rates, higher electric fields are required to achieve deposition. Further, we fInd that AC electric fields at the appropriate frequency can Increase deposition above DC fields at similar strengths. Overall, the study establishes simulation approaches for the design of In Vitro aerosol deposition chambers and relates key process parameters to deposition, which is critical to controllIng the dose of submicron aerosols In In Vitro Toxicology experiments.
Molly M Stevens - One of the best experts on this subject based on the ideXlab platform.
-
In Vitro Toxicology evaluation of pharmaceuticals usIng raman micro spectroscopy
Journal of Cellular Biochemistry, 2006Co-Authors: Chris A Owen, Jamuna Selvakumaran, Ioan Notingher, Gavin Jell, Larry L Hench, Molly M StevensAbstract:Raman micro-spectroscopy combIned with multivariate analysis was employed to monitor real-time biochemical changes Induced In livIng cells In Vitro followIng exposure to a pharmaceutical. The cancer drug etoposide (topoisomerase II Inhibitor) was used to Induce double-strand DNA breaks In human type II pneumocyte-like cells (A549 cell-lIne). Raman spectra of A549 cells exposed to 100 µM etoposide were collected and classical least squares (CLS) analysis used to determIne the relative concentrations of the maIn cellular components. It was found that the concentrations of DNA and RNA significantly (P < 0.05) decreased, whilst the concentration of lipids significantly (P < 0.05) Increased with IncreasIng etoposide exposure time as compared to control untreated A549 cells. The concentration of DNA decreased by 27.5 and 87.0% after 24 and 48 h exposure to etoposide respectively. PrIncipal components analysis (PCA) successfully discrimInated between treated and untreated cells, with the maIn variance between treatment groups attributed to changes In DNA and lipid. DNA fragmentation was confirmed by Western blot analysis of apoptosis regulator proteIn p53 and cell metabolic activity determIned by MTT assay. The over-expression of p53 proteIn In the etoposide treated cells Indicated a significant level of DNA fragmentation and apoptosis. MTT tests confirmed that cellular metabolic activity decreased followIng exposure to etoposide by 29.4 and 61.2% after 24 and 48 h, respectively. Raman micro-spectroscopy may fInd applications In the Toxicology screenIng of other drugs, chemicals and new biomaterials, with a range of cell types. J. Cell. Biochem. © 2006 Wiley-Liss, Inc.
-
In Vitro Toxicology evaluation of pharmaceuticals usIng Raman micro-spectroscopy.
Journal of Cellular Biochemistry, 2006Co-Authors: Chris A Owen, Jamuna Selvakumaran, Ioan Notingher, Gavin Jell, Larry L Hench, Molly M StevensAbstract:Raman micro-spectroscopy combIned with multivariate analysis was employed to monitor real-time biochemical changes Induced In livIng cells In Vitro followIng exposure to a pharmaceutical. The cancer drug etoposide (topoisomerase II Inhibitor) was used to Induce double-strand DNA breaks In human type II pneumocyte-like cells (A549 cell-lIne). Raman spectra of A549 cells exposed to 100 µM etoposide were collected and classical least squares (CLS) analysis used to determIne the relative concentrations of the maIn cellular components. It was found that the concentrations of DNA and RNA significantly (P
Chris A Owen - One of the best experts on this subject based on the ideXlab platform.
-
In Vitro Toxicology evaluation of pharmaceuticals usIng raman micro spectroscopy
Journal of Cellular Biochemistry, 2006Co-Authors: Chris A Owen, Jamuna Selvakumaran, Ioan Notingher, Gavin Jell, Larry L Hench, Molly M StevensAbstract:Raman micro-spectroscopy combIned with multivariate analysis was employed to monitor real-time biochemical changes Induced In livIng cells In Vitro followIng exposure to a pharmaceutical. The cancer drug etoposide (topoisomerase II Inhibitor) was used to Induce double-strand DNA breaks In human type II pneumocyte-like cells (A549 cell-lIne). Raman spectra of A549 cells exposed to 100 µM etoposide were collected and classical least squares (CLS) analysis used to determIne the relative concentrations of the maIn cellular components. It was found that the concentrations of DNA and RNA significantly (P < 0.05) decreased, whilst the concentration of lipids significantly (P < 0.05) Increased with IncreasIng etoposide exposure time as compared to control untreated A549 cells. The concentration of DNA decreased by 27.5 and 87.0% after 24 and 48 h exposure to etoposide respectively. PrIncipal components analysis (PCA) successfully discrimInated between treated and untreated cells, with the maIn variance between treatment groups attributed to changes In DNA and lipid. DNA fragmentation was confirmed by Western blot analysis of apoptosis regulator proteIn p53 and cell metabolic activity determIned by MTT assay. The over-expression of p53 proteIn In the etoposide treated cells Indicated a significant level of DNA fragmentation and apoptosis. MTT tests confirmed that cellular metabolic activity decreased followIng exposure to etoposide by 29.4 and 61.2% after 24 and 48 h, respectively. Raman micro-spectroscopy may fInd applications In the Toxicology screenIng of other drugs, chemicals and new biomaterials, with a range of cell types. J. Cell. Biochem. © 2006 Wiley-Liss, Inc.
-
In Vitro Toxicology evaluation of pharmaceuticals usIng Raman micro-spectroscopy.
Journal of Cellular Biochemistry, 2006Co-Authors: Chris A Owen, Jamuna Selvakumaran, Ioan Notingher, Gavin Jell, Larry L Hench, Molly M StevensAbstract:Raman micro-spectroscopy combIned with multivariate analysis was employed to monitor real-time biochemical changes Induced In livIng cells In Vitro followIng exposure to a pharmaceutical. The cancer drug etoposide (topoisomerase II Inhibitor) was used to Induce double-strand DNA breaks In human type II pneumocyte-like cells (A549 cell-lIne). Raman spectra of A549 cells exposed to 100 µM etoposide were collected and classical least squares (CLS) analysis used to determIne the relative concentrations of the maIn cellular components. It was found that the concentrations of DNA and RNA significantly (P
Shinichi Kinugasa - One of the best experts on this subject based on the ideXlab platform.
-
dispersion characteristics of various metal oxide secondary nanoparticles In culture medium for In Vitro Toxicology assessment
Toxicology in Vitro, 2010Co-Authors: Haruhisa Kato, Mie Suzuki, Katsuhide Fujita, Masanori Horie, Shigehisa Endoh, Yasukazu Yoshida, Hitoshi Iwahashi, Kayori Takahashi, Ayako Nakamura, Shinichi KinugasaAbstract:Abstract The aim of this study is to characterize the dispersion characteristics of various metal oxide nanoparticles and secondary nanoparticle formation In culture medium. Many studies have already Investigated the In Vitro toxicities of various metal oxide nanoparticles; however, there have been few discussions about the particle transport mode to cells durIng a period of toxicity assessment. The particle transport mode would strongly affect the amount of uptake by cells; therefore, estimation of the transport mode for various metal oxide particles is important. Fourteen different metal oxide nanoparticle dispersions In a culture medium were examIned. The sizes of the secondary nanoparticles were observed to be larger than 100 nm by dynamic light scatterIng (DLS). AccordIng to Stokes law and the Stokes–EInsteIn assumption, pure metal oxide particles with such sizes should gravitationally settle faster than diffusion processes; however, the secondary metal oxide particles examIned In this study exhibited unexpectedly slower gravitational settlIng rates. The slow gravitational settlIng kInetics of particles was estimated to be caused by the Inclusion of proteIn Into the secondary nanoparticles, which resulted In lower densities than the pure metal oxide particles. The ratios of metal oxide to proteIn In secondary particles could be affected by the proteIn adsorption ability of the correspondIng metal oxide primary particles. To the best of our knowledge, it was clarified for the first time that stably dispersed secondary metal oxide nanoparticles with slow gravitational settlIng kInetics are Induced by secondary nanoparticles consistIng of small amounts of metal oxide particles and large amounts of proteIn, which results In lower particle densities than the pure metal oxide particles. The estimation of particle dynamics In culture medium usIng this method would be significant to recognize the Inherent toxicity of nanoparticles.
-
reliable size determInation of nanoparticles usIng dynamic light scatterIng method for In Vitro Toxicology assessment
Toxicology in Vitro, 2009Co-Authors: Haruhisa Kato, Mie Suzuki, Katsuhide Fujita, Masanori Horie, Shigehisa Endoh, Yasukazu Yoshida, Hitoshi Iwahashi, Kayori Takahashi, Ayako Nakamura, Shinichi KinugasaAbstract:Abstract Dynamic light scatterIng (DLS) is widely used for the evaluation of the particle size In the toxicity assessment of nanoparticles. However, the many types of DLS Instruments and analytical procedures sometimes give different apparent sizes of particles and make it complicated to understand the size dependence on particles for the toxicity assay. In this study, we established an evaluation method of secondary nanoparticle sizes usIng a DLS analysis. First, we established a practical method for determInIng size with an appropriate evaluation of uncertaInties. This proposed method could be a universal protocol for toxicity assessment that would allow researchers to achieve some degree of concordance on the size of nanoparticles for an assessment. Second, we Investigated the processes associated with particles In suspension by examInIng the changes In the size and the light scatterIng Intensity of secondary nanoparticles durIng an In Vitro toxicity assessment, sInce the transport mode of particles to cells is significant In understandIng In Vitro nano-toxicity. In this study, these two poInts were Investigated on TiO2 nanoparticles suspension as an example. The secondary particles of TiO2 with a light scatterIng Intensity-averaged diameter (dl) of 150–250 nm were characterized with appropriate uncertaInties. The sizes were found to be comparable with values determIned usIng other analytical procedures and other Instruments. It is suggested that dl could be an effective size parameter for toxicity assessments. Furthermore, TiO2 secondary nanoparticle suspensions are well dispersed with slow gravity settlIng, no agglomeration, with the diffusion process as the primary transport mode of particles to cells.
