The Experts below are selected from a list of 195 Experts worldwide ranked by ideXlab platform
Michele Caggana - One of the best experts on this subject based on the ideXlab platform.
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isolation of tumor cells using size and deformation
Journal of Chromatography A, 2009Co-Authors: Hisham Mohamed, Michele Caggana, James N. Turner, M. MurrayAbstract:Abstract The isolation and analysis of circulating tumor cells (CTCs) from blood are the subject of intense research. Although tests to detect metastasis on a molecular level are available, progress has been hampered by a lack of tumor-specific markers and predictable DNA abnormalities. The main challenge in this endeavor is the small number of available cells of interest, 1–2 per mL in whole blood. We have designed a Micromachined Device to fractionate whole blood using physical means to enrich for and/or isolate rare cells from peripheral circulation. It has arrays of four successively narrower channels, each consisting of a two-dimensional array of columns. Current Devices have channels ranging in width from 20 to 5 μm, and in depth from 20 to 5 μm. Several optimizations resulting in the fabrication of a total of 10 derivative Devices have been carried out; only two types are used in this study. Both have increasingly narrower gap widths between the columns along the flow axis with 20, 15, 10, and 5 μm spacing all on one Device. The first 20 μm wide segment disperses the cell suspension and creates an evenly distributed flow over the entire Device, whereas the others were designed to retain increasingly smaller cells. The channel depth is constant across the entire Device, the first type was 10 μm deep and the second type is 20 μm deep. When cells from each of eight tumor cell lines were loaded into the Device, all cancerous cells were isolated. In mixing experiments using human whole blood, we were able to fractionate cancer cells without interference from the blood cells. Additionally, either intact cells, or DNA, could be extracted for molecular analysis. The ultimate goal of this work is to characterize the cells on the molecular level to provide non-invasive methods to monitor patients, stage disease, and assess treatment efficacy. Furthermore, this work will use gene expression profiles to gain insights into metastasis.
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Biochip for separating fetal cells from maternal circulation.
Journal of chromatography. A, 2007Co-Authors: Hisham Mohamed, James N. Turner, Michele CagganaAbstract:Isolation of fetal cells from maternal circulation is the subject of intense research to eliminate the need for currently used invasive prenatal diagnosis procedures. Fetal cells can be isolated using magnetic-activated cell sorting or fluorescence-activated cell sorting, however no technique to specifically isolate and use fetal cells for genetic diagnosis has reached routine clinical practice. This paper demonstrates the use of a Micromachined Device to separate fetal cells from maternal circulation based on differences in size and deformation characteristics. Nucleated fetal red blood cells range in diameter from 9 to 12 microm can deform and pass through a channel as small as 2.5 microm wide and 5 microm deep. Although the white blood cells range in diameter from 10 to 20 microm, they cannot deform and are retained by the 2.5 microm wide and 5 microm deep channels under our experimental conditions. Fetal cells were isolated from cord blood and DNA analysis confirmed their fetal origin with ruled out maternal contamination.
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a Micromachined sparse cell isolation Device application in prenatal diagnostics
TechConnect Briefs, 2006Co-Authors: Hisham Mohamed, James N. Turner, Michele CagganaAbstract:Fetal cells can be isolated using several enrichment methods, however, since no technique to specifically isolate and use them for genetic diagnosis has reached clinical practice, prenatal diagnosis currently requires invasive procedures. A Micromachined Device to fractionate whole blood using physical means to enrich for and/or isolate rare cell types from peripheral circulation was designed. It has arrays of four successively narrower channels, each consisting of a 2-D array of columns. Current Devices have channels ranging in width from 15µm-2.5µm, and are 5µm deep. Fetal nucleated red blood cells were isolated from cord blood reproducibly and molecular analysis confirmed their origin without contamination from maternal DNA. Future studies will provide methods to detect fetal cells from maternal circulation using a non-invasive approach, the risk for fetal loss will be eliminated, and test costs will be decreased.
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Circulating tumor cells: capture with a Micromachined Device
2005Co-Authors: Hisham Mohamed, James N. Turner, M. Murray, Michele CagganaAbstract:The isolation and analysis of circulating tumor cells from blood is the subject of intense research. Tests to detect metastasis are available, but progress has been hampered by the lack of tumor-specific markers and predictable DNA abnormalities. CTCs from solid tumors can be separated from normal hematopoietic cells based on size and other inherent physical and biological properties. The main challenge in this endeavor is the small number of available cells of interest, 1-2 per ml in human whole blood. A Micromachined Device for fractioning whole blood using physical methods to enrich and/or isolate rare cell types from peripheral circulation has been designed. It has four segments of microfluidic channels, each consisting of a 2-D array of columns. The gap between the columns progressively narrows across the Device. Current Devices have channels ranging in width from 20µm down to 5µm, and in depth from 20µm down to 5µm. When healthy adult blood, spiked with cells from each of eight cancer cell lines tested was loaded into the Device, all cancerous cells were retained in a well-defined area of the Device, while blood cells migrated to the output reservoir. Use of these Devices will advance non-invasive methods used to monitor patients, stage disease, and assess treatment. Furthermore, insights into metastasis will be gained.
Michael P. Sheetz - One of the best experts on this subject based on the ideXlab platform.
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UNIT 12.3 Cell Traction
Current protocols in cell biology, 1998Co-Authors: Catherine G. Galbraith, Michael P. SheetzAbstract:Traction forces are exerted by cells on their substratum as they migrate. These forces under the entire cell or subcellular regions can be measured. This unit describes several protocols for making silicone sheets to measure traction forces under the entire cell, as well as a protocol for developing a Micromachined Device to measure forces under subcellular regions.
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A Micromachined Device provides a new bend on fibroblast traction forces
Proceedings of the National Academy of Sciences of the United States of America, 1997Co-Authors: Catherine G. Galbraith, Michael P. SheetzAbstract:We have measured the traction forces generated by fibroblasts using a novel Micromachined Device that is capable of determining the subcellular forces generated by individual adhesive contacts. The front of migrating fibroblasts produced intermittent rearward forces whereas the tail produced larger forward directed forces. None of the forces were steady; they all had periodic fluctuations. The transition between forward and rearward traction forces occurred at the nucleus, not at the rear of the cell or the border between the endoplasm and the ectoplasm. We propose that the coupling of lamella extensions to fluctuating rearward tractions in front of the nuclear region move the front of a fibroblast forward, while force-facilitated release of rear adhesive contacts and anterior-directed tractions allow the region behind the nucleus to advance.
Bernhard Jakoby - One of the best experts on this subject based on the ideXlab platform.
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simultaneous thermal conductivity and diffusivity sensing in liquids using a Micromachined Device
Sensors and Actuators A-physical, 2006Co-Authors: J Kuntner, F Kohl, Bernhard JakobyAbstract:Due to unique features like small thermal masses and reduced conductivities, membrane-based Micromachined thermal sensors offer features superior to those provided by comparable macroscopic measurement setups. In this contribution a Micromachined Device is applied to characterize the thermal transport properties of various liquids. By means of sinusoidal excitation of a heater structure placed on a membrane and recording the resulting temperature at a specified distance using integrated germanium thermistors, the liquid's thermal parameters can be determined. A simple two-dimensional (2D) analytical model allows to interpret the amplitude and the phase of the measured sinusoidal temperature variation yielding both, the thermal conductivity and the diffusivity of the liquid.
James N. Turner - One of the best experts on this subject based on the ideXlab platform.
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isolation of tumor cells using size and deformation
Journal of Chromatography A, 2009Co-Authors: Hisham Mohamed, Michele Caggana, James N. Turner, M. MurrayAbstract:Abstract The isolation and analysis of circulating tumor cells (CTCs) from blood are the subject of intense research. Although tests to detect metastasis on a molecular level are available, progress has been hampered by a lack of tumor-specific markers and predictable DNA abnormalities. The main challenge in this endeavor is the small number of available cells of interest, 1–2 per mL in whole blood. We have designed a Micromachined Device to fractionate whole blood using physical means to enrich for and/or isolate rare cells from peripheral circulation. It has arrays of four successively narrower channels, each consisting of a two-dimensional array of columns. Current Devices have channels ranging in width from 20 to 5 μm, and in depth from 20 to 5 μm. Several optimizations resulting in the fabrication of a total of 10 derivative Devices have been carried out; only two types are used in this study. Both have increasingly narrower gap widths between the columns along the flow axis with 20, 15, 10, and 5 μm spacing all on one Device. The first 20 μm wide segment disperses the cell suspension and creates an evenly distributed flow over the entire Device, whereas the others were designed to retain increasingly smaller cells. The channel depth is constant across the entire Device, the first type was 10 μm deep and the second type is 20 μm deep. When cells from each of eight tumor cell lines were loaded into the Device, all cancerous cells were isolated. In mixing experiments using human whole blood, we were able to fractionate cancer cells without interference from the blood cells. Additionally, either intact cells, or DNA, could be extracted for molecular analysis. The ultimate goal of this work is to characterize the cells on the molecular level to provide non-invasive methods to monitor patients, stage disease, and assess treatment efficacy. Furthermore, this work will use gene expression profiles to gain insights into metastasis.
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Biochip for separating fetal cells from maternal circulation.
Journal of chromatography. A, 2007Co-Authors: Hisham Mohamed, James N. Turner, Michele CagganaAbstract:Isolation of fetal cells from maternal circulation is the subject of intense research to eliminate the need for currently used invasive prenatal diagnosis procedures. Fetal cells can be isolated using magnetic-activated cell sorting or fluorescence-activated cell sorting, however no technique to specifically isolate and use fetal cells for genetic diagnosis has reached routine clinical practice. This paper demonstrates the use of a Micromachined Device to separate fetal cells from maternal circulation based on differences in size and deformation characteristics. Nucleated fetal red blood cells range in diameter from 9 to 12 microm can deform and pass through a channel as small as 2.5 microm wide and 5 microm deep. Although the white blood cells range in diameter from 10 to 20 microm, they cannot deform and are retained by the 2.5 microm wide and 5 microm deep channels under our experimental conditions. Fetal cells were isolated from cord blood and DNA analysis confirmed their fetal origin with ruled out maternal contamination.
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a Micromachined sparse cell isolation Device application in prenatal diagnostics
TechConnect Briefs, 2006Co-Authors: Hisham Mohamed, James N. Turner, Michele CagganaAbstract:Fetal cells can be isolated using several enrichment methods, however, since no technique to specifically isolate and use them for genetic diagnosis has reached clinical practice, prenatal diagnosis currently requires invasive procedures. A Micromachined Device to fractionate whole blood using physical means to enrich for and/or isolate rare cell types from peripheral circulation was designed. It has arrays of four successively narrower channels, each consisting of a 2-D array of columns. Current Devices have channels ranging in width from 15µm-2.5µm, and are 5µm deep. Fetal nucleated red blood cells were isolated from cord blood reproducibly and molecular analysis confirmed their origin without contamination from maternal DNA. Future studies will provide methods to detect fetal cells from maternal circulation using a non-invasive approach, the risk for fetal loss will be eliminated, and test costs will be decreased.
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Circulating tumor cells: capture with a Micromachined Device
2005Co-Authors: Hisham Mohamed, James N. Turner, M. Murray, Michele CagganaAbstract:The isolation and analysis of circulating tumor cells from blood is the subject of intense research. Tests to detect metastasis are available, but progress has been hampered by the lack of tumor-specific markers and predictable DNA abnormalities. CTCs from solid tumors can be separated from normal hematopoietic cells based on size and other inherent physical and biological properties. The main challenge in this endeavor is the small number of available cells of interest, 1-2 per ml in human whole blood. A Micromachined Device for fractioning whole blood using physical methods to enrich and/or isolate rare cell types from peripheral circulation has been designed. It has four segments of microfluidic channels, each consisting of a 2-D array of columns. The gap between the columns progressively narrows across the Device. Current Devices have channels ranging in width from 20µm down to 5µm, and in depth from 20µm down to 5µm. When healthy adult blood, spiked with cells from each of eight cancer cell lines tested was loaded into the Device, all cancerous cells were retained in a well-defined area of the Device, while blood cells migrated to the output reservoir. Use of these Devices will advance non-invasive methods used to monitor patients, stage disease, and assess treatment. Furthermore, insights into metastasis will be gained.
Hisham Mohamed - One of the best experts on this subject based on the ideXlab platform.
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isolation of tumor cells using size and deformation
Journal of Chromatography A, 2009Co-Authors: Hisham Mohamed, Michele Caggana, James N. Turner, M. MurrayAbstract:Abstract The isolation and analysis of circulating tumor cells (CTCs) from blood are the subject of intense research. Although tests to detect metastasis on a molecular level are available, progress has been hampered by a lack of tumor-specific markers and predictable DNA abnormalities. The main challenge in this endeavor is the small number of available cells of interest, 1–2 per mL in whole blood. We have designed a Micromachined Device to fractionate whole blood using physical means to enrich for and/or isolate rare cells from peripheral circulation. It has arrays of four successively narrower channels, each consisting of a two-dimensional array of columns. Current Devices have channels ranging in width from 20 to 5 μm, and in depth from 20 to 5 μm. Several optimizations resulting in the fabrication of a total of 10 derivative Devices have been carried out; only two types are used in this study. Both have increasingly narrower gap widths between the columns along the flow axis with 20, 15, 10, and 5 μm spacing all on one Device. The first 20 μm wide segment disperses the cell suspension and creates an evenly distributed flow over the entire Device, whereas the others were designed to retain increasingly smaller cells. The channel depth is constant across the entire Device, the first type was 10 μm deep and the second type is 20 μm deep. When cells from each of eight tumor cell lines were loaded into the Device, all cancerous cells were isolated. In mixing experiments using human whole blood, we were able to fractionate cancer cells without interference from the blood cells. Additionally, either intact cells, or DNA, could be extracted for molecular analysis. The ultimate goal of this work is to characterize the cells on the molecular level to provide non-invasive methods to monitor patients, stage disease, and assess treatment efficacy. Furthermore, this work will use gene expression profiles to gain insights into metastasis.
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Biochip for separating fetal cells from maternal circulation.
Journal of chromatography. A, 2007Co-Authors: Hisham Mohamed, James N. Turner, Michele CagganaAbstract:Isolation of fetal cells from maternal circulation is the subject of intense research to eliminate the need for currently used invasive prenatal diagnosis procedures. Fetal cells can be isolated using magnetic-activated cell sorting or fluorescence-activated cell sorting, however no technique to specifically isolate and use fetal cells for genetic diagnosis has reached routine clinical practice. This paper demonstrates the use of a Micromachined Device to separate fetal cells from maternal circulation based on differences in size and deformation characteristics. Nucleated fetal red blood cells range in diameter from 9 to 12 microm can deform and pass through a channel as small as 2.5 microm wide and 5 microm deep. Although the white blood cells range in diameter from 10 to 20 microm, they cannot deform and are retained by the 2.5 microm wide and 5 microm deep channels under our experimental conditions. Fetal cells were isolated from cord blood and DNA analysis confirmed their fetal origin with ruled out maternal contamination.
-
a Micromachined sparse cell isolation Device application in prenatal diagnostics
TechConnect Briefs, 2006Co-Authors: Hisham Mohamed, James N. Turner, Michele CagganaAbstract:Fetal cells can be isolated using several enrichment methods, however, since no technique to specifically isolate and use them for genetic diagnosis has reached clinical practice, prenatal diagnosis currently requires invasive procedures. A Micromachined Device to fractionate whole blood using physical means to enrich for and/or isolate rare cell types from peripheral circulation was designed. It has arrays of four successively narrower channels, each consisting of a 2-D array of columns. Current Devices have channels ranging in width from 15µm-2.5µm, and are 5µm deep. Fetal nucleated red blood cells were isolated from cord blood reproducibly and molecular analysis confirmed their origin without contamination from maternal DNA. Future studies will provide methods to detect fetal cells from maternal circulation using a non-invasive approach, the risk for fetal loss will be eliminated, and test costs will be decreased.
-
Circulating tumor cells: capture with a Micromachined Device
2005Co-Authors: Hisham Mohamed, James N. Turner, M. Murray, Michele CagganaAbstract:The isolation and analysis of circulating tumor cells from blood is the subject of intense research. Tests to detect metastasis are available, but progress has been hampered by the lack of tumor-specific markers and predictable DNA abnormalities. CTCs from solid tumors can be separated from normal hematopoietic cells based on size and other inherent physical and biological properties. The main challenge in this endeavor is the small number of available cells of interest, 1-2 per ml in human whole blood. A Micromachined Device for fractioning whole blood using physical methods to enrich and/or isolate rare cell types from peripheral circulation has been designed. It has four segments of microfluidic channels, each consisting of a 2-D array of columns. The gap between the columns progressively narrows across the Device. Current Devices have channels ranging in width from 20µm down to 5µm, and in depth from 20µm down to 5µm. When healthy adult blood, spiked with cells from each of eight cancer cell lines tested was loaded into the Device, all cancerous cells were retained in a well-defined area of the Device, while blood cells migrated to the output reservoir. Use of these Devices will advance non-invasive methods used to monitor patients, stage disease, and assess treatment. Furthermore, insights into metastasis will be gained.