scholarly journals Surface Antifouling Modification on Polyethylene Filtration Membranes by Plasma Polymerization

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5020
Author(s):  
An-Li Hou ◽  
Szu-Yi Wang ◽  
Wen-Pin Lin ◽  
Wei-Hsuan Kuo ◽  
Tsung-Jen Wang ◽  
...  
Keyword(s):  
Ethylene Oxide ◽  
Vinyl Ether ◽  
Photoelectron Spectroscopy ◽  
Mammalian Cells ◽  
Plasma Polymerization ◽  
Chinese Hamster ◽  
Single Step ◽  
Water Contact ◽  
Plasma Polymers ◽  
Naoh Solution

Surface modification on microporous polyethylene (PE) membranes was facilitated by plasma polymerizing with two hydrophilic precursors: ethylene oxide vinyl ether (EO1V) and diethylene oxide vinyl ether (EO2V) to effectively improve the fouling against mammalian cells (Chinese hamster ovary, CHO cells) and proteins (bovine serum albumin, BSA). The plasma polymerization procedure incorporated uniform and pin-hole free ethylene oxide-containing moieties on the filtration membrane in a dry single-step process. The successful deposition of the plasma polymers was verified by Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) analyses. Water contact angle measurements and permeation experiments using cell and protein solutions were conducted to evaluate the change in hydrophilicity and fouling resistance for filtrating biomolecules. The EO1V and EO2V plasma deposited PE membranes showed about 1.45 fold higher filtration performance than the pristine membrane. Moreover, the flux recovery reached 80% and 90% by using deionized (DI) water and sodium hydroxide (NaOH) solution, indicating the efficacy of the modification and the good reusability of the modified PE membranes.

Plasma polymerization of tetrafluoroethylene – towards CF2 dominated fluorocarbon films

e-Polymers ◽  
2006 ◽  
Vol 6 (1) ◽  
Author(s):  
Mirko Nitschke ◽  
Steffi Uhlmann ◽  
Roland Schulze ◽  
Carsten Werner
Keyword(s):  
Photoelectron Spectroscopy ◽  
Plasma Polymerization ◽  
Plasma Polymers ◽  
Pronounced Increase ◽  
Fluorocarbon Films ◽  
Process Gas ◽  
Pressure Discharge ◽  
Discharge Gas ◽  
Substrate Temperatures ◽  
Radio Frequency Discharge

AbstractFluorocarbon films with an exceptionally high CF2 content were obtained by plasma polymerization using a low pressure radio frequency discharge operated with a mixture of argon and tetrafluoroethylene. Substrates were placed in a remote position downstream the discharge. Gas pressure, discharge power, substrate position, gas composition and substrate temperature were changed to alter the chemical structure of the plasma polymers. The properties of the films were characterized by X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry and contact angle goniometry. A pronounced increase of the CF2 content was obtained for elevated substrate temperatures and increased amounts of tetrafluoroethylene in the process gas. Applied as a model surface in studies of interfacial phenomena on polytetrafluoroethylene (PTFE), transparent PTFE-like thin films enable the use of numerous optical techniques not applicable to common PTFE foils.

scholarly journals DERIVATION OF TK- CLONES FROM REVERTANT TK+ MAMMALIAN CELLS

Genetics ◽  
1973 ◽  
Vol 75 (3) ◽  
pp. 515-530
Author(s):  
D J Roufa ◽  
B N Sadow ◽  
C T Caskey
Keyword(s):  
Cell Lines ◽  
Mammalian Cells ◽  
Chinese Hamster ◽  
Chinese Hamster Cell ◽  
Single Step ◽  
Wild Type ◽  
Cell Clones ◽  
Selection Experiments ◽  
Step Selection ◽  
Selection Of

ABSTRACT In order to obtain a large collection of Chinese hamster cell clones defective in thymidine kinase (TK-), BrdUr selection experiments have been performed on wild-type and revertant TK+ cell lines. No clones (< 10-9) were obtained from the wild-type TK+ cell line by single-step selection. In contrast, revertant TK+ clones readily gave rise to stable TK- derivatives (1 - 2 × 10-4). Both wild-type and revertant TK+ clones spontaneously yielded 8-AGr colonies with the same frequency (1 - 5 × 10-6), suggesting that the differences between wild-type and revertant cell lines specifically affected selection of the TK- phenotype. The increased frequency of TK- clones reflects perhaps the number (ploidy) or character of the autosomal TK loci in TK+ revertants, or perhaps the mechanisms which regulate expression of the TK genes. Several mutagens, EMS, MNNG and UV, stimulated the TK+ revertants' frequency of TK- subclones only slightly (< 3-fold). Biochemical and genetic data indicated that the TK- clones derived from one revertant are phenotypically different. The phenotypes displayed by these cell lines are stable and do not depend upon the continued presence of the selective agent.

Ultrastructural Changes in Three Different Mammalian Cells Following Ultraviolet Laser Irradiation

1972 ◽  
Vol 30 ◽  
pp. 350-351
Author(s):  
K. Shankar Narayan ◽  
Kailash C. Gupta ◽  
Tohru Okigaki
Keyword(s):  
Ultraviolet Light ◽  
Mammalian Cells ◽  
Biological Effects ◽  
Survival Rates ◽  
Chinese Hamster ◽  
Cell Types ◽  
Differential Sensitivity ◽  
Ultrastructural Changes ◽  
Ultraviolet Laser

The biological effects of short-wave ultraviolet light has generally been described in terms of changes in cell growth or survival rates and production of chromosomal aberrations. Ultrastructural changes following exposure of cells to ultraviolet light, particularly at 265 nm, have not been reported.We have developed a means of irradiating populations of cells grown in vitro to a monochromatic ultraviolet laser beam at a wavelength of 265 nm based on the method of Johnson. The cell types studies were: i) WI-38, a human diploid fibroblast; ii) CMP, a human adenocarcinoma cell line; and iii) Don C-II, a Chinese hamster fibroblast cell strain. The cells were exposed either in situ or in suspension to the ultraviolet laser (UVL) beam. Irradiated cell populations were studied either "immediately" or following growth for 1-8 days after irradiation.Differential sensitivity, as measured by survival rates were observed in the three cell types studied. Pattern of ultrastructural changes were also different in the three cell types.

scholarly journals A Novel Nanobody Precisely Visualizes Phosphorylated Histone H2AX in Living Cancer Cells under Drug-Induced Replication Stress

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3317
Author(s):  
Eric Moeglin ◽  
Dominique Desplancq ◽  
Audrey Stoessel ◽  
Christian Massute ◽  
Jeremy Ranniger ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Mammalian Cells ◽  
Chromatin Modification ◽  
Replication Stress ◽  
Living Cells ◽  
Single Step ◽  
Dna Double Strand Breaks ◽  
Drug Induced ◽  
Histone H2ax ◽  
C Terminus

Histone H2AX phosphorylated at serine 139 (γ-H2AX) is a hallmark of DNA damage, signaling the presence of DNA double-strand breaks and global replication stress in mammalian cells. While γ-H2AX can be visualized with antibodies in fixed cells, its detection in living cells was so far not possible. Here, we used immune libraries and phage display to isolate nanobodies that specifically bind to γ-H2AX. We solved the crystal structure of the most soluble nanobody in complex with the phosphopeptide corresponding to the C-terminus of γ-H2AX and show the atomic constituents behind its specificity. We engineered a bivalent version of this nanobody and show that bivalency is essential to quantitatively visualize γ-H2AX in fixed drug-treated cells. After labelling with a chemical fluorophore, we were able to detect γ-H2AX in a single-step assay with the same sensitivity as with validated antibodies. Moreover, we produced fluorescent nanobody-dTomato fusion proteins and applied a transduction strategy to visualize with precision γ-H2AX foci present in intact living cells following drug treatment. Together, this novel tool allows performing fast screenings of genotoxic drugs and enables to study the dynamics of this particular chromatin modification in individual cancer cells under a variety of conditions.

Rapid Single-Step Growth of MOF Exoskeleton on Mammalian Cells for Enhanced Cytoprotection

2021 ◽  
Author(s):  
Laura Ha ◽  
UnJin Ryu ◽  
Dong-Chang Kang ◽  
Jung-Kyun Kim ◽  
Dengrong Sun ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Single Step ◽  
Step Growth

Thermotropic lipid and protein transitions in Chinese hamster lung cell membranes: relationship to hyperthermic cell killing

1983 ◽  
Vol 61 (6) ◽  
pp. 421-427 ◽  
Author(s):  
James R. Lepock ◽  
Kwan-Hon Cheng ◽  
Hisham Al-Qysi ◽  
Jack Kruuv
Keyword(s):  
Mammalian Cells ◽  
Plasma Membranes ◽  
Chinese Hamster ◽  
Cell Killing ◽  
Water Soluble ◽  
Growth Data ◽  
Protein Fluorescence ◽  
Polar Groups ◽  
Spin Resonance ◽  
Intrinsic Protein Fluorescence

Exposure of mammalian cells to hyperthermic temperatures (ca. 41–45 °C) appears to act as a direct or triggering effect to produce some later response such as cell death, thermotolerance, or heat-shock protein synthesis. The high activation energy of cell killing indicates that the direct effect of hyperthermia might be a thermotropic transition in some cellular component, for this particular response. Both hyperthermic survival and growth data imply that the temperature for the onset of hyperthermic cell killing is 40–41.5 °C for Chinese hamster lung V79 cells. Studies using the electron spin resonance label 2,2-dimethyl-5-dodecyl-5-methyloxazolidine-N-oxide and the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene show the existence of lipid transitions at approximately 7–8 and 23–36 °C (or a broad transition between these temperatures) in mitochondria and whole cell homogenates, that correlate well with changes in growth and hypothermic killing. No lipid transition was detected near 40–41.5 °C that could correlate with hyperthermic killing in either mitochondrial or plasma membranes, but measurements of intrinsic protein fluorescence and protein fluorophore to trans-paranaric acid energy transfer demonstrate the existence of an irreversible transition in protein structure or arrangement above ca. 40 °C in both mitochondrial and plasma membranes. This transition is due to protein rearrangement and (or) unfolding such that there is increased exposure of protein tryptophan and tyrosine residues to polar groups and to paranaric acid. The strength of the transition implies that a significant fraction of total membrane protein is involved in this transition, which may be analogous to the heat-induced denaturation of water-soluble proteins. This alteration in membrane structure above ca. 40 °C could cause many of the observed changes in plasma membrane and mitochondrial function, which may further be involved in cellular responses to hyperthermia.

scholarly journals Structure of Plasma (re)Polymerized Polylactic Acid Films Fabricated by Plasma-Assisted Vapour Thermal Deposition

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 459
Author(s):  
Zdeněk Krtouš ◽  
Lenka Hanyková ◽  
Ivan Krakovský ◽  
Daniil Nikitin ◽  
Pavel Pleskunov ◽  
...  
Keyword(s):  
Polylactic Acid ◽  
Photoelectron Spectroscopy ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Molecular Structures ◽  
Plasma Polymers ◽  
Thermal Deposition ◽  
X Ray ◽  
Process Chemistry ◽  
Precursor Molecules

Plasma polymer films typically consist of very short fragments of the precursor molecules. That rather limits the applicability of most plasma polymerisation/plasma-enhanced chemical vapour deposition (PECVD) processes in cases where retention of longer molecular structures is desirable. Plasma-assisted vapour thermal deposition (PAVTD) circumvents this limitation by using a classical bulk polymer as a high molecular weight “precursor”. As a model polymer in this study, polylactic acid (PLA) has been used. The resulting PLA-like films were characterised mostly by X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) spectroscopy. The molecular structure of the films was found to be tunable in a broad range: from the structures very similar to bulk PLA polymer to structures that are more typical for films prepared using PECVD. In all cases, PLA-like groups are at least partially preserved. A simplified model of the PAVTD process chemistry was proposed and found to describe well the observed composition of the films. The structure of the PLA-like films demonstrates the ability of plasma-assisted vapour thermal deposition to bridge the typical gap between the classical and plasma polymers.

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