scholarly journals Bioimpedance Analysis of L929 and HaCaT Cells in Low Frequency Range

2018 ◽  
Vol 4 (1) ◽  
pp. 115-118 ◽  
Author(s):  
Viviane S. Teixeira ◽  
Jan-Patrick Kalckhoff ◽  
Wolfgang Krautschneider ◽  
Dietmar Schroeder
Keyword(s):  
Low Frequency ◽  
Steel Corrosion ◽  
Frequency Dispersion ◽  
Human Keratinocytes ◽  
Cell Types ◽  
Hacat Cells ◽  
Frequency Range ◽  
Corrosion Resistant ◽  
L929 Mouse

AbstractIn this work, Bioimpedance Spectroscopy (BIS) is used to study fluids and cell solutions. A n ew fourelectrode- terminal (4T) chamber using 3D printing and stainless steel corrosion resistant V4A was designed to measure the impedance of live cell solutions at the frequency range 0.1Hz- 1MHz. At f < 1kHz the double layer (DL) that builds at electrode’s surface raises the impedance substantially preventing the observation of the real impedance of the cells. The new 4T design circumvents the DL, is more robust and cheap, and allows for the repeatability of the results. Experiments were performed in vitro with two cell lines, L929 (mouse fibroblasts) and HaCaT (human keratinocytes). Results show that it is possible to distinguish between the two cell types by means of its BIS measurements in the new setup. Also, a low-frequency dispersion (α-dispersion) was observed in HaCaT cells solution, but not in L929. Furthermore, a potentiostat circuit model was developed in LTSpice to simulate the hardware setup and two different circuit models were used to fit cell’s data.

scholarly journals HaCaT Cells as a Reliable In Vitro Differentiation Model to Dissect the Inflammatory/Repair Response of Human Keratinocytes

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Irma Colombo ◽  
Enrico Sangiovanni ◽  
Roberta Maggio ◽  
Carlo Mattozzi ◽  
Stefania Zava ◽  
...  
Keyword(s):  
Cell Density ◽  
Skin Diseases ◽  
Inflammatory Responses ◽  
Human Keratinocytes ◽  
Suitable Model ◽  
Hacat Cells ◽  
Primary Human Keratinocytes ◽  
Proinflammatory Mediators ◽  
Cytokines And Chemokines

Cultured primary human keratinocytes are frequently employed for studies of immunological and inflammatory responses; however, interpretation of experimental data may be complicated by donor to donor variability, the relatively short culture lifetime, and variations between passages. To standardize the in vitro studies on keratinocytes, we investigated the use of HaCaT cells, a long-lived, spontaneously immortalized human keratinocyte line which is able to differentiate in vitro, as a suitable model to follow the release of inflammatory and repair mediators in response to TNFα or IL-1β. Different treatment conditions (presence or absence of serum) and differentiation stimuli (increase in cell density as a function of time in culture and elevation of extracellular calcium) were considered. ELISA and Multiplex measurement technologies were used to monitor the production of cytokines and chemokines. Taken together, the results highlight that Ca2+ concentration in the medium, cell density, and presence of serum influences at different levels the release of proinflammatory mediators by HaCaT cells. Moreover, HaCaT cells maintained in low Ca2+ medium and 80% confluent are similar to normal keratinocytes in terms of cytokine production suggesting that HaCaT cells may be a useful model to investigate anti-inflammatory interventions/therapies on skin diseases.

scholarly journals Experimental-Numerical Design and Evaluation of a Vibration Bioreactor Using Piezoelectric Patches

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 436 ◽  
Author(s):  
David Valentín ◽  
Charline Roehr ◽  
Alexandre Presas ◽  
Christian Heiss ◽  
Eduard Egusquiza ◽  
...  
Keyword(s):  
Numerical Model ◽  
Mechanical Vibration ◽  
Cell Types ◽  
Experimental Results ◽  
Cell Behavior ◽  
Frequency Range ◽  
Piezoelectric Patch ◽  
Numerical Design ◽  
Vibration Pattern

In this present study, we propose a method for exposing biological cells to mechanical vibration. The motive for our research was to design a bioreactor prototype in which in-depth in vitro studies about the influence of vibration on cells and their metabolism can be performed. The therapy of cancer or antibacterial measures are applications of interest. In addition, questions about the reaction of neurons to vibration are still largely unanswered. In our methodology, we used a piezoelectric patch (PZTp) for inducing mechanical vibration to the structure. To control the vibration amplitude, the structure could be excited at different frequency ranges, including resonance and non-resonance conditions. Experimental results show the vibration amplitudes expected for every frequency range tested, as well as the vibration pattern of those excitations. These are essential parameters to quantify the effect of vibration on cell behavior. Furthermore, a numerical model was validated with the experimental results presenting accurate results for the prediction of those parameters. With the calibrated numerical model, we will study in greater depth the effects of different vibration patterns for the abovementioned cell types.

scholarly journals Dispersive changes in magnetic background noise polarization at 0.1 to 6Hz during sunset and sunrise at L=1.3

2004 ◽  
Vol 22 (6) ◽  
pp. 1989-2000 ◽  
Author(s):  
T. Bösinger ◽  
S. L. Shalimov
Keyword(s):  
Background Noise ◽  
Azimuthal Angle ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Major Axis ◽  
Resonance Structure ◽  
Frequency Range ◽  
Ionosphere Model ◽  
F Region ◽  
E Region

Abstract. Polarization properties of the magnetic background noise (MBN) and the spectral resonance structure (SRS) of the ionospheric Alfvén resonator (IAR) below the first Schumann resonance but above 0.1 Hz are measured by a sensitive pulsation magnetometer at the island of Crete (L=1.3) and analyzed using the existing SRS theory by Belyaev et al. (1989b). The focus of the paper is on the systematic changes in the MBN and SRS properties associated with the transition from a sunlit to a dark ionosphere (sunset) and vice versa (sunrise). We are able to pinpoint in observations an E-region and F-region terminator effect and to simulate it by means of a simple ionosphere model, implying the formalism given by Belyaev et al. (1989b). The E-region terminator effect is associated with an apparent control for the SRS presence or absence with no clear frequency dispersion in polarization properties, whereas the F-region terminator effect exhibits strong frequency dispersion, especially in the low frequency range. This yields a change in the ellipticity of MBN, starting as early as 2 to 3h ahead of the "zero-line" of the terminator. In a 24h presentation of the ellipticity versus frequency and time, the sunrise/sunset effect produces a sharp, dispersive boundary between night and day (day and night). Only inside this boundary, during the night hours, is SRS observed, at times accompanied by a large quasi-periodic long period modulation in the azimuthal angle of the major axis of the polarization ellipse. Attention is also paid to peculiarities in the low frequency range (~0.1Hz), where especially large changes in the polarization properties occur in association with the passage of the terminator. The F-region effect is very distinct and well reproduced by our simple model. Changes in the azimuth associated with the E-region terminator effect are of the order of 20&amp;deg.

scholarly journals Calycosin Suppresses Epithelial Derived Initiative Key Factors and Maintains Epithelial Barrier in Allergic Inflammation via TLR4 Mediated NF-κB Pathway

2017 ◽  
Vol 44 (3) ◽  
pp. 1106-1119 ◽  
Author(s):  
Yu Tao ◽  
Yan Wang ◽  
Xiaoyu Wang ◽  
Can Wang ◽  
Kaifang Bao ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Western Blot ◽  
Chinese Herb ◽  
Allergic Inflammation ◽  
Human Keratinocytes ◽  
Epithelial Barrier ◽  
Hacat Cells ◽  
Initial Stage

Background/Aims: Calycosin is a bioactive component of Astragali Radix, a Chinese herb for treating allergy. We have previously demonstrated that calycosin effectively inhibited allergic inflammation efficiently. The aim of this study was to explore the mechanism of calycosin on epithelial cells in allergic inflammation. Methods: An initial stage of atopic dermatitis (AD) model in which mice were just sensitized with FITC, was established in vivo and immortalized human keratinocytes (HaCaT cells) were utilized in vitro. Initiative key cytokines, TSLP and IL-33, were measured by ELISA, qPCR, immunofluorescence and Western blot. The junctions in epithelial cells were observed by electron microscopy and tight junctions (TJs) (Occludin and ZO-1) were assessed by Western blot and immunofluorescence. TLR4, MyD88, TAK1, TIRAP and NF-κB were measured by qPCR or Western blot. Results: The results showed that TSLP and IL-33 were inhibited significantly by calycosin in the initial stage of AD model. Simultaneously, calycosin attenuated the separated gap among the epithelial cells and increased the expression of TJs. TSLP/IL-33 and TJs were similarly affected in LPS-stimulated HaCaT cells in vitro. Meanwhile, calycosin not only inhibited the expressions of TLR4, MyD88, TAK1 and TIRAP, but also reduced NF-κB activation in vitro and in vivo. An NF-κB inhibitor enhanced the expressions of TJs and reduced that of TSLP/IL-33 in LPS-stimulated HaCaT cells. Conclusion: These results indicated that calycosin reduced the secretion of TSLP/IL-33 and attenuated the disruption of epithelial TJs by inhibiting TLR4 mediated NF-κB signaling pathway. These findings help to understand the beneficial effects of calycosin on AD, and to develop effective preventive or therapeutic strategies to combat this disease and other epithelial barrier deletion-mediated allergic diseases.

In vitro cytotoxicity of CdSe/ZnS quantum dots with different surface coatings to human keratinocytes HaCaT cells

2013 ◽  
Vol 25 (1) ◽  
pp. 163-171 ◽  
Author(s):  
Kavitha Pathakoti ◽  
Huey-Min Hwang ◽  
Hong Xu ◽  
Zoraida P. Aguilar ◽  
Andrew Wang
Keyword(s):  
Quantum Dots ◽  
Human Keratinocytes ◽  
In Vitro Cytotoxicity ◽  
Surface Coatings ◽  
Hacat Cells

scholarly journals Genotoxic Effect of Arsenate and Arsenite in Human HaCat Cells in Culture Using Comet Assay

2020 ◽  
pp. 36-44
Author(s):  
Ghazalla Benhusein ◽  
Elaine Mutch ◽  
Faith M. Williams
Keyword(s):  
Dna Damage ◽  
Comet Assay ◽  
Statistical Significance ◽  
Human Keratinocytes ◽  
Hacat Cells ◽  
Environmental Chemical ◽  
Viable Cells ◽  
Buthionine Sulphoximine ◽  
Ros Formation

Arsenic is an environmental chemical of toxicological concern today since it is a human genotoxin and chronic exposure is associated with development of cancers, including skin. Inorganic arsenate is metabolically reduced to arsenite by glutathione (GSH) prior to methylation. The aim of this study was to determine the relative toxic effects of arsenate and arsenite in HaCat cells (immortalized human keratinocytes) in vitro by measuring cytotoxicity, DNA damage, depletion of glutathione and apoptotic and necrotic events. HaCat cells were treated with arsenate and arsenite (10 μM) for DNA damage detection using Comet assay and cytotoxicity (10, 60 and 100 μM) all measured at 24 hr. In some experiment arsenate or arsenite (10 μM) was added at the same time as BSO 10 μM for 24 hr, and GSH levels were measured by HPLC with fluorescence detection. Flow cytometry was used to investigate apoptotic and necrotic events following arsenate and arsenite (10 μM) treatment for 24 hr. Arsenate and arsenite at 60 and 100 μM, but not 10 μM, reduced the number of adherent viable cells with time. Therefore, DNA damage could only be measured at 10 μM as at higher concentrations the cells did not produce classical Comets but showed fragmentation. DNA damage was significantly (p < 0.001) increased in cells treated for 24 hr with 10 μM arsenate and arsenite compared to control. GSH levels were significantly increased in HaCat cells treated with10 μM arsenate and arsenite (p < 0.05, p < 0.001, respectively) compared to control. Cells treated with buthionine sulphoximine (BSO) at the same time as arsenate had increased GSH levels (p < 0.001), but arsenite and BSO did not increase cellular GSH. Arsenate and arsenite increased apoptosis, and arsenate increased necrosis, although none of the values reached statistical significance. Arsenite was more cytotoxic than arsenate. Arsenate and arsenite are known to produce oxidative stress involving ROS formation and depletion of glutathione. The increase in GSH levels at low doses of arsenate and arsenite, and by arsenate even in the presence of BSO.

scholarly journals Chitin Nanofibril Application in Tympanic Membrane Scaffolds to Modulate Inflammatory and Immune Response

Pharmaceutics ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1440
Author(s):  
Serena Danti ◽  
Shivesh Anand ◽  
Bahareh Azimi ◽  
Mario Milazzo ◽  
Alessandra Fusco ◽  
...  
Keyword(s):  
Tympanic Membrane ◽  
Weight Ratio ◽  
Human Mesenchymal Stem Cells ◽  
Cell Types ◽  
Collagen Type I ◽  
In Vitro Tests ◽  
Type I ◽  
Hacat Cells ◽  
Polybutylene Terephthalate

Chitin nanofibrils (CNs) are an emerging bio-based nanomaterial. Due to nanometric size and high crystallinity, CNs lose the allergenic features of chitin and interestingly acquire anti-inflammatory activity. Here we investigate the possible advantageous use of CNs in tympanic membrane (TM) scaffolds, as they are usually implanted inside highly inflamed tissue environment due to underlying infectious pathologies. In this study, the applications of CNs in TM scaffolds were twofold. A nanocomposite was used, consisting of poly (ethylene oxide terephthalate)/(polybutylene terephthalate) (PEOT/PBT) copolymer loaded with CN/polyethylene glycol (PEG) pre-composite at 50/50 (w/w %) weight ratio, and electrospun into fiber scaffolds, which were coated by CNs from crustacean or fungal sources via electrospray. The degradation behavior of the scaffolds was investigated during 4 months at 37 °C in an otitis-simulating fluid. In vitro tests were performed using cell types to mimic the eardrum, i.e., human mesenchymal stem cells (hMSCs) for connective, and human dermal keratinocytes (HaCaT cells) for epithelial tissues. HMSCs were able to colonize the scaffolds and produce collagen type I. The inflammatory response of HaCaT cells in contact with the CN-coated scaffolds was investigated, revealing a marked downregulation of the pro-inflammatory cytokines. CN-coated PEOT/PBT/(CN/PEG 50:50) scaffolds showed a significant indirect antimicrobial activity.

The allocation of early blastomeres to the ectoderm and endoderm is variable in the sea urchin embryo

Development ◽  
1997 ◽  
Vol 124 (11) ◽  
pp. 2213-2223 ◽  
Author(s):  
C.Y. Logan ◽  
D.R. McClay
Keyword(s):  
Sea Urchin ◽  
Low Frequency ◽  
Initial Step ◽  
Cell Types ◽  
Lytechinus Variegatus ◽  
Cell Fates ◽  
Cell Stage ◽  
Sea Urchin Embryo

During sea urchin development, a tier-to-tier progression of cell signaling events is thought to segregate the early blastomeres to five different cell lineages by the 60-cell stage (E. H. Davidson, 1989, Development 105, 421–445). For example, the sixth equatorial cleavage produces two tiers of sister cells called ‘veg1′ and ‘veg2,’ which were projected by early studies to be allocated to the ectoderm and endoderm, respectively. Recent in vitro studies have proposed that the segregation of veg1 and veg2 cells to distinct fates involves signaling between the veg1 and veg2 tiers (O. Khaner and F. Wilt, 1991, Development 112, 881–890). However, fate-mapping studies on 60-cell stage embryos have not been performed with modern lineage tracers, and cell interactions between veg1 and veg2 cells have not been shown in vivo. Therefore, as an initial step towards examining how archenteron precursors are specified, a clonal analysis of veg1 and veg2 cells was performed using the lipophilic dye, DiI(C16), in the sea urchin species, Lytechinus variegatus. Both veg1 and veg2 descendants form archenteron tissues, revealing that the ectoderm and endoderm are not segregated at the sixth cleavage. Also, this division does not demarcate cell type boundaries within the endoderm, because both veg1 and veg2 descendants make an overlapping range of endodermal cell types. The allocation of veg1 cells to ectoderm and endoderm during cleavage is variable, as revealed by both the failure of veg1 descendants labeled at the eighth equatorial division to segregate predictably to either tissue and the large differences in the numbers of veg1 descendants that contribute to the ectoderm. Furthermore, DiI-labeled mesomeres of 32-cell stage embryos also contribute to the endoderm at a low frequency. These results show that the prospective archenteron is produced by a larger population of cleavage-stage blastomeres than believed previously. The segregation of veg1 cells to the ectoderm and endoderm occurs relatively late during development and is unpredictable, indicating that later cell position is more important than the early cleavage pattern in determining ectodermal and archenteron cell fates.

scholarly journals An integrated systems biology approach to understanding the rules of keratinocyte colony formation

2007 ◽  
Vol 4 (17) ◽  
pp. 1077-1092 ◽  
Author(s):  
Tao Sun ◽  
Phil McMinn ◽  
Simon Coakley ◽  
Mike Holcombe ◽  
Rod Smallwood ◽  
...  
Keyword(s):  
Human Keratinocytes ◽  
Self Organization ◽  
Hacat Cells ◽  
Agent Based ◽  
Wound Model ◽  
Cell Substrate ◽  
Scratch Wound ◽  
Keratinocyte Cell Line Hacat ◽  
Keratinocyte Cell

Closely coupled in vitro and in virtuo models have been used to explore the self-organization of normal human keratinocytes (NHK). Although it can be observed experimentally, we lack the tools to explore many biological rules that govern NHK self-organization. An agent-based computational model was developed, based on rules derived from literature, which predicts the dynamic multicellular morphogenesis of NHK and of a keratinocyte cell line (HaCat cells) under varying extracellular Ca ++ concentrations. The model enables in virtuo exploration of the relative importance of biological rules and was used to test hypotheses in virtuo which were subsequently examined in vitro . Results indicated that cell–cell and cell–substrate adhesions were critically important to NHK self-organization. In contrast, cell cycle length and the number of divisions that transit-amplifying cells could undergo proved non-critical to the final organization. Two further hypotheses, to explain the growth behaviour of HaCat cells, were explored in virtuo —an inability to differentiate and a differing sensitivity to extracellular calcium. In vitro experimentation provided some support for both hypotheses. For NHKs, the prediction was made that the position of stem cells would influence the pattern of cell migration post-wounding. This was then confirmed experimentally using a scratch wound model.

Interdigital Ag(Ta,Nb)O3 thin Film Capacitors on Sapphire

2001 ◽  
Vol 688 ◽  
Author(s):  
Jung-Hyuk Koh ◽  
Alex Grishin ◽  
Akira Shibuya ◽  
Masanori Okuyama
Keyword(s):  
Low Frequency ◽  
Frequency Dispersion ◽  
Low Noise ◽  
Laser Deposition ◽  
Frequency Range ◽  
High Tunability ◽  
Thin Film Capacitors ◽  
Dielectric Performance ◽  
Tan Δ ◽  
High Dielectric

AbstractPolycrystalline 0.4 μm thick films of Ag(Ta,Nb)O3 (ATN) were grown on sapphire (Al2O3-0112, r-plane) wafers by pulsed laser deposition technique. 2 and 4 μm gap interdigital capacitors were defined by photolithography on the top of Au/Cr/ATN(0.4μm)/Al2O3 film structures. They exhibit high dielectric performance. In the frequency range of 1 kHz to 1 MHz dielectric permittivity shows frequency dispersion as low as 3.5 %, loss tangent ∼ 0.0035 @ 1 MHz, Kfactor = tunability/tan δ is about 20.2 @ 200 kV/cm, and resistivity as high as 1.8 × 1011 ×cm @ 100 kV/cm. C-V and I-V characteristics recorded in time domain revealed slow Curie-von Schweidler-type relaxation of the polarization. Low frequency dispersion and loss, high tunability and low noise in the biased state promise thin ATN film capacitors for microwave applications.

Sign in / Sign up

Export Citation Format

Share Document