scholarly journals Colloidal quantum dots suitability for long term cell imaging

2018 ◽  
Author(s):  
Patricia M. A. Farias ◽  
André Galembeck ◽  
Raquel Milani ◽  
Wilson S. Mendonca ◽  
Andreas Stingl
Keyword(s):  
Quantum Dots ◽  
Polyethylene Glycol ◽  
Cell Viability ◽  
Glial Cells ◽  
Aqueous Suspension ◽  
High Rate ◽  
Term Monitoring ◽  
Observation Period

AbstractFluorescent semiconductor nanoparticles in tree-dimensional quantum confinement, quantum dots (QDs), synthesized in aqueous medium, and functionalized with polyethylene glycol, were used as probes for the long-term imaging of glial cells. In vitro living healthy as well as cancer glial cells were labelled by direct insertion of a small volume of QDs contained in aqueous suspension into the culture wells. A long-term monitoring (over 7 days) of the cells was performed and no evidence of cell fixation and/or damage was observed. Two control groups, healthy and cancer glial cells, were used to compare cell viability. During the observation period, labelled and non labelled cells presented the same dynamics and no difference was observed regarding cell viability. To our knowledge, this is the first report of the viability of hydrophilic prepared quantum dots without any further surface treatment than the polyethylene-glycol coverage for the long-term imaging of living cells. Further, the study also permitted the observation of two distinct interaction mechanisms between cells and QDs. Healthy glial cells were mainly labelled at their surface, while non-healthy glial cells have shown a high rate in the uptake of QDs.

scholarly journals The Colloidal Quantum Dots Suitability for Long Term Cell Imaging

2018 ◽  
Vol 15 (2) ◽  
pp. 6275-6281
Author(s):  
Patricia M. A. Farias ◽  
André Galembeck ◽  
Raquel Milani ◽  
Wilson S. Mendonca ◽  
Andreas Stingl
Keyword(s):  
Quantum Dots ◽  
Glial Cells ◽  
Aqueous Suspension ◽  
High Rate ◽  
Cellular Mechanisms ◽  
Interaction Kinetics ◽  
Term Monitoring ◽  
Observation Period

Fluorescent semiconductor nanoparticles in tree-dimensional quantum confinement, quantum dots (QDs), synthesized in aqueous medium, and functionalized with polyethylene glycol, were used as nonspecific nanosized probes for the long-term imaging of glial cells. In vitro living healthy as well as cancer glial cells were labelled by direct insertion of a small volume of QDs contained in aqueous suspension into the culture wells. A long-term monitoring (over 7 days) of the cells was performed and no evidence of cell fixation and/or damage was observed. Two control groups, healthy and non-healthy glial cells, were used to compare cell viability. During the observation period, labelled cells kept the same behavior compared to non-labelled control samples. To our knowledge, this is the first report of the viability of quantum dots for long-term imaging of living cells. This opens a large range of possibilities related to a better understand of cellular mechanisms, which till now was not achieved by any other fluorescent probe. The study also permitted the observation of two distinct interaction kinetics between cells and QDs. Healthy glial cells were mainly labelled at their surface, while non-healthy glial cells have shown a high rate in the uptake of QDs.

scholarly journals A microfluidic-based cell encapsulation platform to achieve high long-term cell viability in photopolymerized PEGNB hydrogel microspheres

2017 ◽  
Vol 5 (1) ◽  
pp. 173-180 ◽  
Author(s):  
Zhongliang Jiang ◽  
Bingzhao Xia ◽  
Ralph McBride ◽  
John Oakey
Keyword(s):  
Tissue Engineering ◽  
Polyethylene Glycol ◽  
Regenerative Medicine ◽  
Cell Viability ◽  
Cell Encapsulation ◽  
Cell Delivery ◽  
Cellular Behavior ◽  
Hydrogel Scaffolds

Cell encapsulation within photopolymerized polyethylene glycol (PEG)-based hydrogel scaffolds has been demonstrated as a robust strategy for cell delivery, tissue engineering, regenerative medicine, and developing in vitro platforms to study cellular behavior and fate.

Long-term In Vitro Toxicity Models: Comparisons Between a Flow-cell Bioreactor, a Static-cell Bioreactor and Static Cell Cultures

2002 ◽  
Vol 30 (5) ◽  
pp. 515-523 ◽  
Author(s):  
Patricia Pazos ◽  
Salvador Fortaner ◽  
Pilar Prieto
Keyword(s):  
Cell Culture ◽  
Cell Viability ◽  
Flow Cell ◽  
Model Systems ◽  
In Vitro Toxicity ◽  
Protein Determination ◽  
Efficient System ◽  
Cytotoxicity Studies

In vitro long-term toxicity testing is becoming an important issue in the field of toxicology, and there is a need to develop new model systems that mimic human chronic exposure and its effects. The aim of this work was to test two long-term in vitro toxicity systems which are available, a flow-cell bioreactor (Tecnomouse) and a static cell bioreactor system (CELLine CL 6-well), and to compare them with the use of conventional cell culture flasks. A human cell line, Int 407, was exposed to cadmium chloride (CdCl2; 10–7–10–8M) for 4 weeks. Cell numbers and cell viabilities were determined by the trypan blue (TB) exclusion assay and from exclusion of propidium iodide (PI) as determined by flow cytometry; and cell viability and metabolic activity were determined by the MTT assay. In addition, total protein determination and cadmium uptake measurements were performed. The results obtained with TB and PI exclusion did not show clear differences in cell viability with increasing CdCl2 concentration. However, in the static cell-culture systems, an increase in MTT reduction was found at low concentrations of CdCl2. Expression of heat-shock protein (Hsp27 and Hsp70) increased differently, depending on the CdCl2 concentration applied and the system used. In summary, of the two bioreactors, the CELLine CL 6-well bioreactor was shown to be the more efficient system for performing long-term cytotoxicity studies. It is easy to handle, it permits the assessment of several endpoints, and sufficient replicates can be made available.

scholarly journals Loading Graphene Quantum Dots into Optical-Magneto Nanoparticles for Real-Time Tracking In Vivo

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2191 ◽  
Author(s):  
Yu Wang ◽  
Nan Xu ◽  
Yongkai He ◽  
Jingyun Wang ◽  
Dan Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Real Time ◽  
Fluorescent Dyes ◽  
Graphene Quantum Dots ◽  
Shell Nanoparticles ◽  
One Pot ◽  
Real Time Tracking

Fluorescence imaging offers a new approach to visualize real-time details on a cellular level in vitro and in vivo without radioactive damage. Poor light stability of organic fluorescent dyes makes long-term imaging difficult. Due to their outstanding optical properties and unique structural features, graphene quantum dots (GQDs) are promising in the field of imaging for real-time tracking in vivo. At present, GQDs are mainly loaded on the surface of nanoparticles. In this study, we developed an efficient and convenient one-pot method to load GQDs into nanoparticles, leading to longer metabolic processes in blood and increased delivery of GQDs to tumors. Optical-magneto ferroferric oxide@polypyrrole (Fe3O4@PPy) core-shell nanoparticles were chosen for their potential use in cancer therapy. The in vivo results demonstrated that by loading GQDs, it was possible to monitor the distribution and metabolism of nanoparticles. This study provided new insights into the application of GQDs in long-term in vivo real-time tracking.

Nontoxic Silicon Nanocrystals and Nanodiamonds as Substitution for Harmful Quantum Dots

2009 ◽  
Vol 1241 ◽  
Author(s):  
Anna Fucikova ◽  
Jan Valenta ◽  
Ivan Pelant ◽  
Vitezslav Brezina
Keyword(s):  
Quantum Dots ◽  
Chemical Composition ◽  
Silicon Nanocrystals ◽  
Nanocrystalline Silicon ◽  
Semiconductor Quantum Dots ◽  
In Vivo Studies ◽  
Long Term Stability

AbstractThe commercially available semiconductor quantum dots have been proven to be slightly to significantly toxic by recent publications depending on the chemical composition. We are developing new non-toxic fluorescent labels based on (i) nanocrystalline silicon, suitable for in vivo studies due to their biodegrability, and on (ii) nanodiamonds, intended mainly for in vitro use due to their long-term stability and nondegradilibity.

scholarly journals Oligodendrocytes support axonal transport and maintenance via exosome secretion

2019 ◽  
Author(s):  
Carsten Frühbeis ◽  
Wen Ping Kuo-Elsner ◽  
Christina Müller ◽  
Kerstin Barth ◽  
Leticia Peris ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Glial Cells ◽  
Axonal Degeneration ◽  
Specific Gene ◽  
Neuronal Viability ◽  
Mouse Mutants ◽  
Gene Defects ◽  
Term Maintenance

AbstractNeurons extend long axons that require maintenance and are susceptible to degeneration. Long-term integrity of axons depends on intrinsic mechanisms including axonal transport and extrinsic support from adjacent glial cells. The mechanisms of support provided by myelinating oligodendrocytes to underlying axons are only partly understood. Oligodendrocytes release extracellular vesicles (EVs) with properties of exosomes, which upon delivery to neurons improve neuronal viability in vitro. Here, we show that oligodendroglial exosome secretion is impaired in two mouse mutants exhibiting secondary axonal degeneration due to oligodendrocyte-specific gene defects. Wildtype oligodendroglial exosomes support neurons by improving the metabolic state and promoting axonal transport in nutrient deprived neurons. Mutant oligodendrocytes release less exosomes that share a common signature of underrepresented proteins. Notably, mutant exosomes lack the ability to support nutrient deprived neurons and to promote axonal transport. Together, these findings indicate that glia to neuron exosome transfer promotes neuronal long-term maintenance by facilitating axonal transport, providing a novel mechanistic link between myelin diseases and secondary loss of axonal integrity.

scholarly journals An In Vitro Investigation of Cytotoxic Effects of InP/Zns Quantum Dots with Different Surface Chemistries

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 135 ◽  
Author(s):  
Deanna Ayupova ◽  
Garima Dobhal ◽  
Geoffry Laufersky ◽  
Thomas Nann ◽  
Renee Goreham
Keyword(s):  
Quantum Dots ◽  
Polyethylene Glycol ◽  
Indium Phosphide ◽  
Membrane Integrity ◽  
Zinc Sulphide ◽  
Cytotoxic Effects ◽  
Quantitative Evidence ◽  
In Vitro Investigation ◽  
Surface Chemistries

Indium phosphide quantum dots (QDs) passivated with zinc sulphide in a core/shell architecture (InP/ZnS) with different surface chemistries were introduced to RAW 264.7 murine “macrophage-like” cells to understand their potential toxicities. The InP/ZnS quantum dots were conjugated with an oligonucleotide, a carboxylic acid, or an amino-polyethylene glycol ligand, and cell viability and cell proliferation were investigated via a metabolic assay. Membrane integrity was measured through the production of lactate dehydrogenase. Fluorescence microscopy showed cellular uptake. All quantum dots exhibited cytotoxic behaviour less than that observed from cadmium- or lead-based quantum dots; however, this behaviour was sensitive to the ligands used. In particular, the amino-polyethylene glycol conjugated quantum dots proved to possess the highest cytotoxicity examined here. This provides quantitative evidence that aqueous InP/ZnS quantum dots can offer a safer alternative for bioimaging or in therapeutic applications.

Evidence for paracrine/autocrine regulation of GLP-1-producing cells

2013 ◽  
Vol 305 (10) ◽  
pp. C1041-C1049 ◽  
Author(s):  
Camilla Kappe ◽  
Qimin Zhang ◽  
Jens J. Holst ◽  
Thomas Nyström ◽  
Åke Sjöholm
Keyword(s):  
Cell Viability ◽  
Insulin Signaling ◽  
Dipeptidyl Peptidase 4 ◽  
Beneficial Effects ◽  
Novel Drugs ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

Glucagon-like peptide-1 (GLP-1), secreted from gut L cells upon nutrient intake, forms the basis for novel drugs against type 2 diabetes (T2D). Secretion of GLP-1 has been suggested to be impaired in T2D and in conditions associated with hyperlipidemia and insulin resistance. Further, recent studies support lipotoxicity of GLP-1-producing cells in vitro. However, little is known about the regulation of L-cell viability/function, the effects of insulin signaling, or the potential effects of stable GLP-1 analogs and dipeptidyl peptidase-4 (DPP-4) inhibitors. We determined effects of insulin as well as possible autocrine action of GLP-1 on viability/apoptosis of GLP-1-secreting cells in the presence/absence of palmitate, while also assessing direct effects on function. The studies were performed using the GLP-1-secreting cell line GLUTag, and palmitate was used to simulate hyperlipidemia. Our results show that palmitate induced production of reactive oxygen species and caspase-3 activity and reduced cell viability are significantly attenuated by preincubation with insulin/exendin-4. The indicated lipoprotective effect of insulin/exendin-4 was not detectable in the presence of the GLP-1 receptor (GLP-1R) antagonist exendin (9–39) and attenuated in response to pharmacological inhibition of exchange protein activated by cAMP (Epac) signaling, while protein kinase A inhibition had no significant effect. Insulin/exendin-4 also significantly stimulate acute and long-term GLP-1 secretion in the presence of glucose, suggesting novel beneficial effects of insulin signaling and GLP-1R activation on glycemia through enhanced mass of GLP-1-producing cells and enhanced GLP-1 secretion. In addition, the effects of insulin indicate that not only is GLP-1 important for insulin secretion but altered insulin signaling may contribute to an altered GLP-1 secretion.

scholarly journals Musa sp. paradisiaca Cultivar Gopi and Clonal fidelity Assessment using ISSR Marker

2019 ◽  
Vol 29 (2) ◽  
pp. 175-184
Author(s):  
Rabindra Kumar Sinha ◽  
Puja Rani Saha ◽  
Bibhash Nath ◽  
H. Reshmi Singha ◽  
Anath Bandhu Das ◽  
...  
Keyword(s):  
Shoot Multiplication ◽  
Shoot Elongation ◽  
High Rate ◽  
Clonal Fidelity ◽  
Musa Sp ◽  
Inter Simple Sequence Repeats ◽  
Fidelity Assessment ◽  
Simple Sequence

Attempt was made towards optimizing an in vitro shoot multiplication of banana cultivar Gopi with subsequent assessment of genetic stability. Experiments on enhanced shoot multiplication were conducted in MS fortified with BAP, Kn and 2-iP (4 mg/l) for a period of 8 weeks. Administration of exogenous root inducing growth regulator was eliminated to reduce culture investment and economy. Treatment with BAP supplemented medium proved to be optimum for shoot multiplication whereas 2-iP produced satisfactory results for shoot elongation. Long term incubation in all the treatments had been favorable for developing efficient root system. Hardening of in vitro grown plantlets showed high rate of survival (95%) upon transfer to potted soil. Assessment of clonal fidelity through inter simple sequence repeats (ISSR) analysis revealed 100% uniformity.

scholarly journals New Insights into the Cell Death Signaling Pathways Triggered by Long-Term Exposure to Silicon-Based Quantum Dots in Human Lung Fibroblasts

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 323
Author(s):  
Miruna S. Stan ◽  
Smaranda Badea ◽  
Anca Hermenean ◽  
Hildegard Herman ◽  
Bogdan Trica ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cell Viability ◽  
Human Lung ◽  
Control Level ◽  
Lung Fibroblasts ◽  
Population Doubling ◽  
Blue Staining ◽  
Human Lung Fibroblasts ◽  
Silicon Based

This report is the first research study that aims to explore the molecular mechanisms involved in the in vitro pulmonary cytotoxicity triggered by long-term exposure to silicon-based quantum dots (QDs). Human lung fibroblasts (MRC-5 cell line) were exposed to 5 µg/mL silicon-based QDs for 5 weeks and the concentration was increased up to 40 µg/mL QDs during the next 4 weeks. Cell viability and population doubling level were calculated based on Trypan blue staining. The expression levels of proteins were established by Western blotting and the telomeres’ length was determined through Southern blotting. Prolonged exposure of lung fibroblasts to QDs reduced the cell viability by 10% compared to untreated cells. The level of p53 and apoptosis-inducing factor (AIF) expression increased during the exposure, the peak intensity being registered after the seventh week. The expressions of autophagy-related proteins, Beclin-1 and LC-3, were higher compared to untreated cells. Regarding the protein expression of Nrf-2, a progressive decrease was noticed, suggesting the downregulation of a cytoprotective response to oxidative stress. In contrast, the heat shock proteins’ (HSPs) expression was increased or maintained near the control level during QDs exposure in order to promote cell survival. Furthermore, the telomeres’ length was not reduced during this exposure, indicating that QDs did not induce cellular senescence. In conclusion, our study shows that silicon-based QDs triggered the activation of apoptotic and autophagy pathways and downregulation of survival signaling molecules as an adaptive response to cellular stress which was not associated with telomeres shortening.

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