The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Michael R. Hamblin - One of the best experts on this subject based on the ideXlab platform.
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Molecular Delivery into a Lipid Bilayer with a Single Shock Waves Using Molecular Dynamic Simulation
AIP Conference Proceedings, 2005Co-Authors: Kenichiro Koshiyama, Tetsuya Kodama, Michael R. Hamblin, Apostolos G. Doukas, Takeru Yano, Shigeo FujikawaAbstract:Cell Permeabilization by shock waves may have application in gene therapy and anticancer drug delivery. In the present study we performed direct molecular dynamic (MD) simulation of the interaction of a single shock wave with a Cell membrane to investigate the mechanism of the Cell Permeabilization. The shock wave was characterized by an impulse that was expressed with a velocity determined by the change in the momentum. The Cell membrane was designed as a dipalmitoylphosphatidylcholine (DPPC) lipid bilayer placed between two layers of water molecules. The MD simulation determined the relationship between water penetration into the bilayer, the order parameter, the fluidity of each lipid molecule, and the intensity of impulse. These structural changes in the bilayer may be an important factor in the use of shock waves to produce transient membrane permeability.
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Shock wave-mediated molecular delivery into Cells
Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 2002Co-Authors: Tetsuya Kodama, Apostolos G. Doukas, Michael R. HamblinAbstract:AbstractA single shock wave generated by a shock tube is able to effectively deliver macromolecules such as fluorescein isothiocyanate–dextran into the cytoplasm of living Cells without causing cytotoxicity. We report on the effect of varying the molecular weight of the dextran and the number of shock waves on the efficiency of delivery into a cancer Cell line. The fraction of Cells permeabilized and the total fluorescence delivered were measured by flow cytometry, and the Cellular viability by a tetrazolium assay on adherent Cells and these values were compared to Cell Permeabilization using digitonin. Shock waves can deliver molecules of up to 2 000 000 molecular weight into the cytoplasm of Cells without toxicity and may have applications in gene therapy
Enrico Cabib - One of the best experts on this subject based on the ideXlab platform.
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Yeast Cell Permeabilization by osmotic shock allows determination of enzymatic activities in situ.
Analytical biochemistry, 2001Co-Authors: Luciana B. Crotti, Tomas Drgon, Enrico CabibAbstract:Yeast Cells were permeabilized by incubation in 0.8 M sorbitol followed by suspension in dilute buffer. A preincubation with 2-mercaptoethanol was also included for optimal Permeabilization. More than 90% of the treated Cells were stainable with methylene blue. Determinations of Cell wall-synthesizing enzymes (beta(1 --> 3)glucan and chitin synthases) and cytosolic enzymes in permeabilized Cells yielded similar or higher activities than those in Cell extracts. With chitin synthase III, the activity obtained with Cells was 4- to 6-fold higher than in membrane preparations. Little protein leaks from the Cells during Permeabilization; yet the Cells appear to be readily permeable to substrates and even proteins. Thus, these preparations may be of wide use for the study of enzymes and of biological processes in situ.
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Yeast Cell Permeabilization by osmotic shock allows determination of enzymatic activities in situ.
Analytical Biochemistry, 2001Co-Authors: Luciana B. Crotti, Tomas Drgon, Enrico CabibAbstract:Abstract Yeast Cells were permeabilized by incubation in 0.8 M sorbitol followed by suspension in dilute buffer. A preincubation with 2-mercaptoethanol was also included for optimal Permeabilization. More than 90% of the treated Cells were stainable with methylene blue. Determinations of Cell wall-synthesizing enzymes (β(1 → 3)glucan and chitin synthases) and cytosolic enzymes in permeabilized Cells yielded similar or higher activities than those in Cell extracts. With chitin synthase III, the activity obtained with Cells was 4- to 6-fold higher than in membrane preparations. Little protein leaks from the Cells during Permeabilization; yet the Cells appear to be readily permeable to substrates and even proteins. Thus, these preparations may be of wide use for the study of enzymes and of biological processes in situ.
Tianfeng Chen - One of the best experts on this subject based on the ideXlab platform.
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Research Article Enhancement of Cell Permeabilization apoptosis-inducing activity of selenium nanoparticles by ATP surface decoration
2013Co-Authors: Yibo Zhang, Zhi Huang, Wenjie Zheng, Cundong Fan, Tianfeng ChenAbstract:A simple method for preparation of adenosine triphosphate (ATP) surface-functionalized selenium nanoparticles (SeNPs@ATP) with enhanced Cell Permeabilization and anticancer activity has been demonstrated in the study reported in this article. Spherical SeNPs were decorated with ATP by strong adsorption through an Se-N bond, leading to the highly stable structure of the conjugates. ATP surface decoration significantly enhanced the Cellular uptake and anticancer activity of SeNPs. Induction of apoptosis in HepG2 human hepatoCellular carcinoma Cells by SeNPs@ATP was evidenced by accumulation of the sub-G1 Cell population, phosphatidylserine exposure, DNA fragmentation, PARP cleavage and caspase activation. Further studies found that SeNPs@ATP treatment triggered the depletion of mitochondrial membrane potential and reactive oxygen species (ROS) overproduction. Our results demonstrate that the use of ATP as a surface decorator of SeNPs is a novel strategy to achieve anticancer synergy. SeNPs@ATP may be a candidate for further evaluation as a chemotherapeutic agent for human cancers.
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Enhancement of Cell Permeabilization apoptosis-inducing activity of selenium nanoparticles by ATP surface decoration
Nanomedicine: Nanotechnology Biology and Medicine, 2013Co-Authors: Yibo Zhang, Zhi Huang, Wenjie Zheng, Cundong Fan, Tianfeng ChenAbstract:Abstract A simple method for preparation of adenosine triphosphate (ATP) surface-functionalized selenium nanoparticles (SeNPs@ATP) with enhanced Cell Permeabilization and anticancer activity has been demonstrated in the study reported in this article. Spherical SeNPs were decorated with ATP by strong adsorption through an Se-N bond, leading to the highly stable structure of the conjugates. ATP surface decoration significantly enhanced the Cellular uptake and anticancer activity of SeNPs. Induction of apoptosis in HepG2 human hepatoCellular carcinoma Cells by SeNPs@ATP was evidenced by accumulation of the sub-G1 Cell population, phosphatidylserine exposure, DNA fragmentation, PARP cleavage and caspase activation. Further studies found that SeNPs@ATP treatment triggered the depletion of mitochondrial membrane potential and reactive oxygen species (ROS) overproduction. Our results demonstrate that the use of ATP as a surface decorator of SeNPs is a novel strategy to achieve anticancer synergy. SeNPs@ATP may be a candidate for further evaluation as a chemotherapeutic agent for human cancers. From the Clinical Editor In this paper, adenosine triphosphate (ATP) surface-functionalized selenium nanoparticles are discussed as Cell-penetrating anticancer agents. Conjugates are stable and ATP functionalization greatly enhances the apoptosis induction properties of the selenium nanoparticles in HepG2 human hepatoCellular carcinoma Cells.
Vladimír Farkaš - One of the best experts on this subject based on the ideXlab platform.
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In situ assays of fungal enzymes in Cells permeabilized by osmotic shock.
Analytical Biochemistry, 2001Co-Authors: Sergej Šesták, Vladimír FarkašAbstract:Abstract Permeabilization of yeast and other fungal Cells by osmotic shock enabled the in situ assays of intraCellular plasma membrane-bound enzymes, such as β-1,3-glucan synthase, chitin synthase, and Na + /K + ATPase as well as the soluble, cytoplasmic enzymes, such as lactate dehydrogenase and α-glucosidase. The Permeabilization was accomplished by rapid changes in osmolarity of the washing buffer at 0°C whereby 0.5–3.5 M glycerol, sorbitol, and/or mannitol and/or 1 M KCl could be used as the osmolytes. No appreciable leakage of intraCellular proteins occurred during the Permeabilization procedure. The described procedure caused practically complete Cell Permeabilization while avoiding treatments with organic solvents, detergents, and other xenobiotics currently used for the Permeabilization of microbial Cells.
Andre Pichette - One of the best experts on this subject based on the ideXlab platform.
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haemolytic activity cytotoxicity and membrane Cell Permeabilization of semi synthetic and natural lupane and oleanane type saponins
Bioorganic & Medicinal Chemistry, 2009Co-Authors: Karl Girardlalancette, Vakhtang Mshvildadze, Andre PichetteAbstract:Abstract The haemolysis of red blood Cells inducing toxicity in most animals including humans is a major drawback for the clinical development of saponins as antitumour agents. In this study, the haemolytic and cytotoxic activities as well as the membrane Cell Permeabilization property of a library of 31 semi-synthetic and natural lupane- and oleanane-type saponins were evaluated and the structure–activity relationships were established. It was shown that lupane-type saponins do not exhibit any haemolytic activity and membrane Cell Permeabilization property at the maximum concentration tested (100 μM) independently of the nature of the sugar moieties. While oleanane-type saponins such as β-hederin ( 25 ) and hederacolchiside A 1 ( 27 ) cause the death of cancer Cell lines by permeabilizing the Cellular membranes, lupane-type saponins seem to proceed via another mechanism, which could be related to the induction of apoptosis. Altogether, the results indicate that the cytotoxic lupane-type glycosides 10 and 22 bearing an α- l -rhamnopyranose moiety at the C-3 position represent promising antitumour agents for further studies on tumour-bearing mice since they are devoid of toxicity associated with the haemolysis of red blood Cells.
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Haemolytic activity, cytotoxicity and membrane Cell Permeabilization of semi-synthetic and natural lupane- and oleanane-type saponins.
Bioorganic & Medicinal Chemistry, 2009Co-Authors: Karl Girard-lalancette, Vakhtang Mshvildadze, Andre PichetteAbstract:The haemolysis of red blood Cells inducing toxicity in most animals including humans is a major drawback for the clinical development of saponins as antitumour agents. In this study, the haemolytic and cytotoxic activities as well as the membrane Cell Permeabilization property of a library of 31 semi-synthetic and natural lupane- and oleanane-type saponins were evaluated and the structure-activity relationships were established. It was shown that lupane-type saponins do not exhibit any haemolytic activity and membrane Cell Permeabilization property at the maximum concentration tested (100 microM) independently of the nature of the sugar moieties. While oleanane-type saponins such as beta-hederin (25) and hederacolchiside A(1) (27) cause the death of cancer Cell lines by permeabilizing the Cellular membranes, lupane-type saponins seem to proceed via another mechanism, which could be related to the induction of apoptosis. Altogether, the results indicate that the cytotoxic lupane-type glycosides 10 and 22 bearing an alpha-l-rhamnopyranose moiety at the C-3 position represent promising antitumour agents for further studies on tumour-bearing mice since they are devoid of toxicity associated with the haemolysis of red blood Cells.