Our Publications Database

Article 47

Changes in the packing of bilayer lipids triggered by electroporation: real-time measurements on cells in suspension

 

Journal: Bioelectrochemistry

Year: 2021

DOI: 10.1016/j.bioelechem.2020.107689

 Electroporation; Generalized polarization; Laurdan; Membrane lipid peroxidation; ROS production; Real-time measurements.

     Electropermeabilization of the cell membrane is a technique used to facilitate penetration of impermeant molecules into cells. Although there are studies regarding the mechanism of processes occurring after electropermeabilization, the relationship between electropermeabilization and associated phenomena (e.g. generation of reactive oxygen species, endocytosis, lipid peroxidation, etc.) is yet to be elucidated. This work aimed to get information on the changes in the packing of the bilayer lipids and their peroxidation induced by application of electroporation pulses. We used a specially designed system of electrodes which allowed performing electropermeabilization of cells in suspension simultaneously with time-dependent measurements of fluorescence and temperature. The kinetics of membrane packing and production of reactive oxygen species were studied using various conductivity buffers (0.01, 0.04 and 0.14 S/m) and different number of 1 kV/cm bipolar pulses (1-50). Two categories of effects were observed: a thermal effect, consisting in an increased bilayer disorder (a deeper penetration of water into the hydrophobic core), and a nonthermal effect, leading to a higher degree of lipids packing, the latter being attributed to a peroxidation process. An analysis of the permeabilization conditions in which one of these two processes predominates was performed.

Article 46

Influence of surfactant-tailored Mn-doped ZnO nanoparticles on ROS production and DNA damage induced in murine fibroblast cells

Traian Popescu, Christien Oktaviani Matei, Ioana Dorina Vlaicu, Ioan Tivig, Andrei Cristian Kuncser, Mariana Stefan, Daniela Ghica, Luminita Claudia Miclea, Tudor Savopol, Daniela Cristina Culita, Mihaela Georgeta Moisescu

Journal: Nature Scientific Reports

Year: 2020

DOI: 10.1038/s41598-020-74816-0

Cell biology, Chemistry, Materials science

     The present study concerns the in vitro oxidative stress responses of non-malignant murine cells exposed to surfactant-tailored ZnO nanoparticles (NPs) with distinct morphologies and different levels of manganese doping. Two series of Mn-doped ZnO NPs were obtained by coprecipitation synthesis method, in the presence of either polyvinylpyrrolidone (PVP) or sodium hexametaphosphate (SHMTP). The samples were investigated by powder X-ray Diffraction, Transmission Electron Microscopy, Fourier-Transform Infrared and Electron Paramagnetic Resonance spectroscopic methods, and N2 adsorption-desorption analysis. The observed surfactant-dependent effects concerned: i) particle size and morphology; ii) Mn-doping level; iii) specific surface area and porosity. The relationship between the surfactant dependent characteristics of the Mn-doped ZnO NPs and their in vitro toxicity was assessed by studying the cell viability, intracellular reactive oxygen species (ROS) generation, and DNA fragmentation in NIH3T3 fibroblast cells. The results indicated a positive correlation between the specific surface area and the magnitude of the induced toxicological effects and suggested that Mn-doping exerted a protective effect on cells by diminishing the pro-oxidative action associated with the increase in the specific BET area. The obtained results support the possibility to modulate the in vitro toxicity of ZnO nanomaterials by surfactant-controlled Mn-doping.

Article 44

Effects of Ibrutinib on biophysical parameters of platelet in patients with chronic lymphocytic leukaemia

Popov, Viola Maria; Matei, Christien Oktaviani; Omer, Meilin; Onisai, Minodora; Matei, Mircea Bogdan; Savopol, Tudor; Bumbea,Horia; Moisescu, Mihaela G.

Journal: American Journal of Blood Research

Year: 2020

ISSN:2160-1992

  

 

Ibrutinib; leukemia; platelets; membrane potential; ROS

Patients with chronic lymphocytic leukemia (CLL) treated with Ibrutinib often present hemorrhagic complications. Platelets dysfunction is well documented by aggregometry and flow cytometry, but the mechanisms by which Ibrutinib treatment influences the platelets status is yet to be evaluated. The aim of this study is to identify platelet membrane parameters in chronic lymphocytic leukemia (CLL) that could be altered by Ibrutinib administration. In this paper we propose a set of fluorescence measurements of the following parameters: membrane fluidity, resting membrane potential, and reactive oxygen species production of platelets suspensions obtained from CLL patients treated or not with Ibrutinib as markers for platelets status in this pathological situation. Platelets from CLL patients treated with Ibrutinib have higher membrane fluidity, lower resting membrane potential and higher level of reactive oxygen species production compared to the untreated CLL patients. These patients are also presenting higher membrane fluidity and lower resting membrane potential compared to healthy volunteers.

 

Article 42

An experimental system for real-time fluorescence recordings of cell membrane changes induced by electroporation

Ioan Tivig, Tudor Savopol, Eugenia Kovacs, Mihaela G Moisescu

Journal: European Biophysical Journal

Year: 2020

DOI: 10.1007/s00249-019-01417-9

3D prototyping; Electric field modeling; Electroporation; Generalized polarization; Real-time fluorescence recording.

     The electroporation of cells is nowadays used for a large variety of purposes, from basic research to cancer therapy and food processing. Understanding molecular mechanisms of the main processes involved in electroporation is thus of significant interest. In the present work, we propose an experimental system to record in real time the evolution of any cell parameter which can be evaluated by fluorescence (before, during and after application of the electroporation pulses to cells in suspension). The system is based on the design of adequate electroporation electrodes, compatible with a standard spectrofluorometer cuvette housing. The electric field intensity generated when pulses are applied was carefully characterized for different geometries of the electrodes, to choose a construction ensuring the greatest homogeneity of the field in combination with the best possible illumination of the sample. As an example of the method’s application, we present here generalized polarization kinetics for a varying number of electroporation pulses applied to a cell suspension; the general polarization parameter is strongly correlated to water presence in the hydrophobic membrane core. The system may be used for many other fluorescence measurements useful for the characterization of the electroporation process.

Article 39

Noninvasive detection of changes in cells' cytosol conductivity by combining dielectrophoresis with optical tweezers

Moisescu, Mihaela Georgeta; Savopol, Tudor; Dimitriu, Liviu; Cemazar, Jaka; Kovacs, Eugenia; Radu, Mihai

Journal: Analytica Chimica ACTA

Year: 2018

DOI: 10.1016/j.aca.2018.05.010  

 

Cytosol conductivity; Dielectrophoresis; Optical tweezers; Electroporation; Clausius-Mossotti factor; Murine melanoma cells

Cellular electrical properties are modulated by various physical and/or chemical stresses and detection of these changes is a challenging issue. Optical tweezers (OT) and dielectrophoresis (DEP) are frequently integrated to devices dedicated to the investigation of cells properties. Here we provide a technique to detect changes in cytosol conductivity of cells by using a combination of DEP and OT. The method was exemplified for the case of cells electroporation and is based on balancing the DEP force by a controlled OT force. We observed a decrease of the DEP force in the case of electroporated cells which was correlated to a decrease of cytosol conductivity by means of Clausius- Mossotti factor modeling. For highly stressing electroporation pulses, the cytosol conductivity drops to values close to those of the cells suspending medium. These results are consistent with those reported in the literature proving the robustness of our proposed sensing method. (C) 2018 Elsevier B.V. All rights reserved.

Article 38

Evaluation of the metastatic potential of malignant cells by image processing of digital holographic microscopy data

Violeta L Calin, Mona Mihailescu, Eugen I Scarlat, Alexandra V Baluta, Daniel Calin, Eugenia Kovacs, Tudor Savopol, Mihaela G. Moisescu

Journal: FEBS Open Bio

Year: 2017

DOI: 10.1002/2211-5463.12282

Bimodality coefficient analysis of quantitative phase image; Clonogenic test; Digital holographic microscopy; Impedance‐based cell proliferation test; Metastatic potential; Murine B16 malignant cells

The cell refractive index has been proposed as a putative cancer biomarker of great potential, being correlated with cell content and morphology, cell division rate and membrane permeability. We used digital holographic microscopy to compare the refractive index and dry mass density of two B16 murine melanoma sublines of different metastatic potential. Using statistical methods, the distribution of phase shifts within the reconstructed quantitative phase images was analyzed by the method of bimodality coefficients. The observed correlation of refractive index, dry mass density and bimodality profile with the metastatic potential of the cells was validated by real time impedance-based assay and clonogenic tests. We suggest that the refractive index and bimodality analysis of quantitative phase image histograms could be developed as optical biomarkers useful in label-free detection and quantitative evaluation of cell metastatic potential.

Article 37

Vegetable Oils Microwave Heating - CUPRAC, TEAC and FRAP Values in Relation with Oxidative Parameters

Iosif, Liviu; Gaman, Laura; Gilca, Marilena; Radoi, Mugurel; Kovacs, Eugenia; Stoian, Irina; Dragos, Dorin

Journal: Revista de Chimie

Year: 2017

DOI: 10.37358/RC.17.8.5793

 

Vegetable oils, Total antioxidant capacity; Lipid peroxidation; Microwave heating CUPRAC; FRAP

 

Microwave heating is a common cooking procedure. Heating can accelerate oxidative processes in oil sand oxidation products are known to have potential toxic effects on human health. Therefore it would be useful to have a method to anticipate the vegetable oils behaviour under thermal conditions. Several methods to evaluate total oxidant activity were developed but unfortunatelly their ability to predict the oxidative changes during heating are poorly estimated. In this study we evaluated the relation of TEAC FRAP and CUPRAC values together with total polyphenols and flavonoids content of several commercial available vegetable oils with conjugated dienes and TBAR’s products during 15 min microwave heating. FRAP values were correlated with oxidative parameters after 15 min heating

Article 36

Changes in optical properties of electroporated cells as revealed by digital holographic microscopy

Violeta L Calin, Mona Mihailescu, Nicolae Mihale, Alexandra V. Baluta, Eugenia Kovacs, Tudor Savopol, Mihaela G. Moisescu

Journal: Biomedical Optics Express

Year: 2017

DOI: 10.1364/BOE.8.002222 

Digital holography; Medical optics and biotechnology; Cell analysis

Changes in optical and shape-related characteristics of B16F10 cells after electroporation were investigated using digital holographic microscopy (DHM). Bipolar rectangular pulses specific for electrochemotherapy were used. Electroporation was performed in an “off-axis” DHM set-up without using exogenous markers. Two types of cell parameters were monitored seconds and minutes after pulse train application: parameters addressing a specifically defined area of the cell (refractive index and cell height) and global cell parameters (projected area, optical phase shift profile and dry mass). The biphasic behavior of cellular parameters was explained by water and mannitol dynamics through the electropermeabilized cell membrane.

Article 35

Polygonum bistorta L. herba et flores. Polyphenols profile, antioxidant properties and cytotoxic effect on murine fibroblast cell line NIH3T3

Lucia Pîrvu, Fawzia Sha’at, Luminița Claudia Miclea, Tudor Savopol, Georgeta Neagu, Denisa Ioana Udeanu, Mihaela Georgeta Moisescu

Journal: Farmacia

Year: 2017

DOI: 10.1364/BOE.8.002222

Polygonum bistorta, Polyphenols, Antioxidant, Cytotoxicity, Fibroblast cells, NIH3T3

This work aimed to study the polyphenols content, the antioxidant activity and the potential cytotoxic effects on fibroblast
murine cells NIH3T3 of an ethanolic extract (70%, v/v) obtained from the aerial part (herba et flores) of Polygonum bistorta
L. (Polygonaceae family). The tested extract was assessed for its total phenols content: 1.15 mg gallic acid equivalents
(GAE) per 1 mL extract and showed numerous flavonoids compounds such as quercetin, kaempferol and luteolin derivates,
as well as caffeic and chlorogenic phenolic acids. The chemiluminescence (CL) tests indicated a high antioxidant capacity
(IC50 = 0.57 µg GAE/mL), superior to gallic acid (IC50 = 0.85 µg/mL) and rutin (IC50 = 2.54 µg/mL), used as reference
compounds. The cytotoxicity test demonstrated that, at concentrations over 25 µg GAE/mL extract, the ethanolic extracts
from the aerial part of Polygonum bistorta plant species have a significant toxicity on mouse embryonic fibroblast NIH3T3 cells.

Article 33

Hemorrhagic risk due to platelet dysfunction in myelodysplastic patients, correlations with anemia severity and iron overload

Popov, Viola M.; Vladareanu, Ana M.; Bumbea, Horia; Kovacs, Eugenia; Savopol, Tudor; Iordache, Maria M.; Moisescu, Mihaela G.

Journal: Blood Coagulation & Fibrinolysis

Year: 2015

DOI: 10.1097/MBC.0000000000000287 

Aggregation; Anemias; Hemorrhages; Hemosideroses; Membrane glycoproteins; Myelodysplastic syndrome; Platelet

Platelet function is influenced by changes in membrane fluidity that has an important role in the expression of platelet receptors and in modulating the activity of proteins like phospholipase C or proteinkinase C. In freshly prepared platelets, membrane fluidity modifies the aggregation/agglutination function. Reactive oxygen species (ROS) represent another important parameter involved in platelet receptor activation. There is a certain association of high levels of ROS and iron overload. Patients with hemochromatosis have low platelet aggregation induced by thrombin; little is known about the anemia and effects of iron overload on platelet activation in myelodysplastic syndromes (MDS) patients. Study of platelet membrane fluidity and ROS production changes in patients with MDS and possible correlations with altered platelet function as reflected in aggregation curves and platelet receptor expression. To find out possible correlations of fluidity of platelet membrane and ROS level with hematologic parameters and iron levels. The prospective study included 34 patients with myelodysplastic syndromes classified according to French-American-British cooperative group proposals and 29 healthy volunteers. Platelet membrane fluidity was quantified by fluorescence anisotropy measurements using the marker 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene p-toluenesulfonate. ROS production was evaluated by fluorescence measurements using 2′,7′-dichlorodihydrofluorescein diacetate. Platelet function was analyzed by optical aggregometry using the agonists adenosine diphosphate, collagen, ristocetin and epinephrine. The expression of platelet receptors CD41/ CD61, CD42a/CD42b and CD62P/CD63 was evaluated by flow cytometry. Platelet membrane fluidity in patients with MDS was similar to that of healthy volunteers and did not vary according to the risk category. Patients with MDS had increased platelet ROS production compared with the control group without statistical correlation with membrane fluidity. We found a negative correlation of ROS levels with the severity of anemia (R=-0.587, P=0.017). Platelet response was reduced in patients with MDS compared with volunteers, for all reagents. The response was different according to the risk category only in case of ristocetin or collagen. Patients with anemia presented a decreased platelet aggregation induced by collagen or ristocetin (collagen: R=0.395, P=0.003; ristocetin: R=0.420, P=0.002). The membrane fluidity of platelets from MDS patients appeared unmodified, but the ROS production was increased in all risk categories of MDS. The levels of ROS were correlated with the degree of anemia, which, in turn, had a negative impact on the platelet aggregation function induced by collagen or ristocetin. Copyright (c) 2015 Wolters Kluwer Health, Inc. All rights reserved.

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