scholarly journals Settling dynamics of nanoparticles in simple and biological media

2021 ◽  
Vol 8 (11) ◽  
Author(s):  
Francesco Giorgi ◽  
Peter Macko ◽  
Judith M. Curran ◽  
Maurice Whelan ◽  
Andrew Worth ◽  
...  

The biological response of organisms exposed to nanoparticles is often studied in vitro using adherent monolayers of cultured cells. In order to derive accurate concentration–response relationships, it is important to determine the local concentration of nanoparticles to which the cells are actually exposed rather than the nominal concentration of nanoparticles in the cell culture medium. In this study, the sedimentation–diffusion process of different sized and charged gold nanoparticles has been investigated in vitro by evaluating their settling dynamics and by developing a theoretical model to predict the concentration depth profile of nanoparticles in solution over time. Experiments were carried out in water and in cell culture media at a range of controlled temperatures. The optical phenomenon of caustics was exploited to track nanoparticles in real time in a conventional optical microscope without any requirement for fluorescent labelling that potentially affects the dynamics of the nanoparticles. The results obtained demonstrate that size, temperature and the stability of the nanoparticles play a pivotal role in regulating the settling dynamics of nanoparticles. For gold nanoparticles larger than 60 nm in diameter, the initial nominal concentration did not accurately represent the concentration of nanoparticles local to the cells. Finally, the theoretical model proposed accurately described the settling dynamics of the nanoparticles and thus represents a promising tool to support the design of in vitro experiments and the study of concentration–response relationships.

2020 ◽  
Author(s):  
francesco giorgi ◽  
Peter Macko ◽  
Judith M. Curran ◽  
Maurice Whelan ◽  
Andrew Worth ◽  
...  

Abstract Background The biological response of organisms exposed to nanoparticles is often studied in vitro using adherent monolayers of cultured cells. In order to derive accurate concentration-response relationships, it is important to determine the local concentration of nanoparticles to which the cells are actually exposed rather than the nominal concentration of nanoparticles in the cell-culture medium. In this study, we investigated the sedimentation–diffusion process of different sized and charged gold nanoparticles in vitro by evaluating their settling dynamics and by developing a theoretical model to predict the concentration depth-profile of nanoparticles in solution over time.Results Experiments were carried out in water and in cell-culture media at a range of controlled temperatures. The optical phenomenon of caustics was exploited to track nanoparticles in real-time in a conventional optical microscope without any requirement for fluorescent labelling that potentially affects the dynamics of the nanoparticles. The results obtained demonstrate that size, temperature, and the stability of the nanoparticles play a pivotal role in regulating settling dynamics of nanoparticles. For gold nanoparticles larger than 60 nm in diameter, the initial nominal concentration did not accurately represent the concentration of nanoparticles local to the cells.Conclusion Nanoparticles dynamics in solution regulate the amount of material at the cellular level and must be taken into account when evaluating the biological response of organisms. the theoretical model proposed in this study accurately described the settling dynamics of the nanoparticles and thus represents a promising tool to support the design of in vitro experiments and the study of concentration-response relationships.


Author(s):  
Amine Ourahmane ◽  
Xiaohong Cui ◽  
Li He ◽  
Dirk Dittmer ◽  
Mark Schleiss ◽  
...  

Propagation of human cytomegalovirus (CMV) in cultured cells results in genetic adaptations that confer improved growth in vitro and significant attenuation in vivo. Mutations in RL13 arise quickly during cell culture passage, while mutations in the UL128-131A locus emerge later during fibroblast passage and disrupt expression of a glycoprotein complex that is important for entry into epithelial and endothelial cells. As in vivo CMV replicates in the context of host antibodies, we reasoned that antibodies might mitigate the accumulation of adaptive mutations during cell culture passage. To test this, CMV in infant urine was used to infect replicate fibroblast cultures. One lineage was passaged in the absence of CMV-hyperimmuneglobulin (HIG) while the other was passaged with HIG in the culture medium. The former lost epithelial tropism and aquired mutations disrupting RL13 and UL131A expression, whereas the latter retained epithelial tropism and both gene loci remained intact after 22 passages. An epitheliotropic RL13+/ UL131A+ virus was isolated by limiting-dilution in the presence of HIG and expanded to produce a working stock sufficient to conduct cell tropism experiments. Thus, culture in the presence of antibodies may facilitate in vitro experiments using viruses that are genetically more authentic than has been previously possible.


Viruses ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 221 ◽  
Author(s):  
Amine Ourahmane ◽  
Xiaohong Cui ◽  
Li He ◽  
Meaghan Catron ◽  
Dirk Dittmer ◽  
...  

Propagation of human cytomegalovirus (CMV) in cultured cells results in genetic adaptations that confer improved growth in vitro and significant attenuation in vivo. Mutations in RL13 arise quickly, while mutations in the UL128-131A locus emerge later during fibroblast passage and disrupt formation of a glycoprotein complex that is important for entry into epithelial and endothelial cells. As CMV replicates in the context of host antibodies in vivo, we reasoned that antibodies might mitigate the accumulation of adaptive mutations during cell culture passage. To test this, CMV in infant urine was used to infect replicate fibroblast cultures. One lineage was passaged in the absence of CMV-hyperimmuneglobulin (HIG) while the other was passaged with HIG in the culture medium. The former lost epithelial tropism and acquired mutations disrupting RL13 and UL131A expression, whereas the latter retained epithelial tropism and both gene loci remained intact after 22 passages. Additional mutations resulting in single amino acid changes also occurred in UL100 encoding glycoprotein M, UL102 encoding a subunit of the helicase/primase complex, and UL122 encoding the Immediate Early 2 protein. An epitheliotropic RL13+/UL131A+ virus was isolated by limiting dilution in the presence of HIG and expanded to produce a working stock sufficient to conduct cell tropism experiments. Thus, production of virus stocks by culture in the presence of antibodies may facilitate in vitro experiments using viruses that are genetically more authentic than previously available.


2016 ◽  
Vol 69 (12) ◽  
pp. 1402 ◽  
Author(s):  
Zahrah Alhalili ◽  
Daniela Figueroa ◽  
Martin R. Johnston ◽  
Joe Shapter ◽  
Barbara Sanderson

The current study evaluated the potential of gold nanoparticles (AuNPs) for the delivery of Taxol to breast cancer cells (T47D) using an in vitro cell culture model. For this study, new loading approaches and novel chemical attachments were investigated. Five different gold nanoparticle-based complexes were used to determine their cytotoxicity towards T47D cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay. There was no significant decrease (P > 0.05) in cell viability when T47D cells were treated with AuNPs that did not contain Taxol. However, cells were significantly killed by gold nanoparticles chemically conjugated to Taxol using three different approaches and one novel hybrid AuNP-Taxol nanoparticle, wherein no chemical bonds were involved. These Taxol-loaded AuNPs were more effective at inducing cell death in vitro than a solution of free Taxol used to treat cells. This result demonstrated that Taxol could be released from the particles in the cell culture media for subsequent therapeutic action. Additionally, the experiments proved that the Taxol-loaded AuNPs were more toxic in a dose dependent manner than Taxol as a formulation for the treatment of breast cancer cells. The results of this study suggest that gold nanoparticles have potential for the efficient delivery of Taxol to breast cancer cells. This could provide a future solution as an alternative application method to overcome adverse side effects resulting from current high-dose treatment regimes.


2013 ◽  
Vol 2013 ◽  
pp. 1-22 ◽  
Author(s):  
Ana Lúcia Vargas Arigony ◽  
Iuri Marques de Oliveira ◽  
Miriana Machado ◽  
Diana Lilian Bordin ◽  
Lothar Bergter ◽  
...  

Micronutrients, including minerals and vitamins, are indispensable to DNA metabolic pathways and thus are as important for life as macronutrients. Without the proper nutrients, genomic instability compromises homeostasis, leading to chronic diseases and certain types of cancer. Cell-culture media try to mimic thein vivoenvironment, providingin vitromodels used to infer cells' responses to different stimuli. This review summarizes and discusses studies of cell-culture supplementation with micronutrients that can increase cell viability and genomic stability, with a particular focus on previousin vitroexperiments. In these studies, the cell-culture media include certain vitamins and minerals at concentrations not equal to the physiological levels. In many common culture media, the sole source of micronutrients is fetal bovine serum (FBS), which contributes to only 5–10% of the media composition. Minimal attention has been dedicated to FBS composition, micronutrients in cell cultures as a whole, or the influence of micronutrients on the viability and genetics of cultured cells. Further studies better evaluating micronutrients' roles at a molecular level and influence on the genomic stability of cells are still needed.


1971 ◽  
Vol 68 (1_Suppl) ◽  
pp. S27-S40 ◽  
Author(s):  
T. Kobayashi ◽  
T. Kigawa ◽  
M. Mizuno ◽  
T. Watanabe

ABSTRACT There are several in vitro methods to analyse the function of the adenohypophysis or the mechanisms of its regulation. The present paper deals with single cell culture, organ culture and short term incubation techniques by which the morphology and gonadotrophin-secreting function of the adenohypophysis were studied. In trypsin-dispersed cell culture, the adenohypophysial cells showed extensive propagation to form numerous cell colonies and finally develop into a confluent monolayer cell sheet covering completely the surface of culture vessels. Almost all of the cultured cells, however, became chromophobic, at least at the end of the first week of cultivation, when gonadotrophin was detectable neither in the culture medium nor in the cells themselves. After the addition of the hypothalamic extract, gonadotrophin became detectable again, and basophilic or PAS-positive granules also reappeared within the cells, suggesting that the gonadotrophs were stimulated by the extract to produce gonadotrophin. In organ culture and short term incubation, the incorporation of [3H] leucine into the adenohypophysial cells in relation to the addition of hypothalamic extract was examined. It was obvious that the ability to incorporate [3H] leucine into the gonadotrophs in vitro was highly dependent upon the presence of the hypothalamic extract.


1992 ◽  
Vol 20 (1) ◽  
pp. 138-143
Author(s):  
Maria Carrara ◽  
Lorenzo Cima ◽  
Roberto Cerini ◽  
Maurizio Dalle Carbonare

A method has been developed whereby cosmetic products which are not soluble in water or in alcohol can be brought into contact with cell cultures by being placed in a cell culture insert, which is then placed in the cell culture well. Preliminary experiments were carried out with L929 cells, and cytotoxicity was evaluated by measuring neutral red uptake and the total protein content of treated cultured cells. Encouraging results were obtained in comparisons of three cosmetic emulsions and of one emulsion containing a range of concentrations of two preservatives, Kathon CG and Bronopol.


Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 765
Author(s):  
Qianbin Zhao ◽  
Tim Cole ◽  
Yuxin Zhang ◽  
Shi-Yang Tang

Organ-on-a-chip (OOC) uses the microfluidic 3D cell culture principle to reproduce organ- or tissue-level functionality at a small scale instead of replicating the entire human organ. This provides an alternative to animal models for drug development and environmental toxicology screening. In addition to the biomimetic 3D microarchitecture and cell–cell interactions, it has been demonstrated that mechanical stimuli such as shear stress and mechanical strain significantly influence cell behavior and their response to pharmaceuticals. Microfluidics is capable of precisely manipulating the fluid of a microenvironment within a 3D cell culture platform. As a result, many OOC prototypes leverage microfluidic technology to reproduce the mechanically dynamic microenvironment on-chip and achieve enhanced in vitro functional organ models. Unlike shear stress that can be readily generated and precisely controlled using commercial pumping systems, dynamic systems for generating proper levels of mechanical strains are more complicated, and often require miniaturization and specialized designs. As such, this review proposes to summarize innovative microfluidic OOC platforms utilizing mechanical actuators that induce deflection of cultured cells/tissues for replicating the dynamic microenvironment of human organs.


2017 ◽  
Vol 3 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Bernhard Hiebl ◽  
Sinem Peters ◽  
Ole Gemeinhardt ◽  
Stefan M. Niehues ◽  
Friedrich Jung

Antioxidants ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 157 ◽  
Author(s):  
Joao Fonseca ◽  
Fereshteh Moradi ◽  
Andrew Valente ◽  
Jeffrey Stuart

Resveratrol is a plant-derived polyphenol that has been widely studied for its putative health promoting effects. Many of those studies have been conducted in cell culture, in supra-physiological levels of oxygen and glucose. Resveratrol interacts with reactive oxygen species (ROS) as an antioxidant or pro-oxidant. Resveratrol affects the expression and activities of ROS-producing enzymes and organelles. It is therefore important to consider how cell culture conditions might determine the effects of resveratrol on cultured cells. We determined the effects of resveratrol on cell growth, hydrogen peroxide production, and mitochondrial network characteristics in C2C12 mouse myoblasts and PC3 human prostate cancer cells under conditions of physiological (5%) and supra-physiological (18%) oxygen, and normo- (5 mM) and hyper-glycemia (25 mM). Interestingly, most effects of resveratrol on the parameters measured here were dependent upon prevailing oxygen and glucose levels during the experiment. Many of the effects of resveratrol on cell growth, hydrogen peroxide production, and mitochondrial network characteristics that were seen in 25 mM glucose and/or 18% oxygen were absent under the physiologically relevant conditions of 5 mM glucose with 5% oxygen. These findings emphasize the importance of using physiologically meaningful starting conditions for cell-culture experiments with resveratrol and indeed any manipulation affecting ROS metabolism and mitochondria.


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