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Cytokinesis following mitosisMembrane Ruffling
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The basic principle of ECIS was first reported by Giaever and Keese, then at the General Electric Corporate Research and Development Center. Giaever, I. And Keese, C.R. PNAS 81, 3761-3764 (1984). ECIS Electric Cell-substrate Impedance Sensing
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250 µm WE CE WE: Working Electrode CE: Counter Electrode The ECIS Electrodes
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250 m Array Holder in Incubator Space ECIS 8 well Array
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ECIS Electric Cell-substrate Impedance Sensing A cell morphology biosensor <1 A, 4000 Hz The measurement is non-invasive AC Current source PC ECIS electrode Counter electrode Culture medium (electrolyte) Phase sensitive impedance measurement PC R C
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Cell Inoculation (10 5 cells per cm 2 ) BSC-1cells NRK cells No cells
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A published model fits the experimental data The measured impedance can be broken down into three parameters 1) Rb, the barrier function of the cell layer 2) Alpha, a term associated with the constricted current flow beneath the cell 3) Cm, the membrane capacitance [Giaever, I. and Keese, C.R., PNAS 81, 3761 (1991)]
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Detection of single cell activity
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What is measured using ECIS? Cell morphology changes including: 1) Barrier function of confluent layers 2) Relative size of cells and spaces beneath cells 3) Membrane capacitance All measurements are made in normal culture medium The measurement is non- invasive Limitations Cells must anchor and spread upon substratum A limited population of cells is measured at one time (1 to 1,000 cells)
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DNA RNA Viral Infection Glucose Oxygen COOH OOCCH 3 Drugs Ligand Binding Physical Changes Shear, Electric Fields Changes in Cell Morphology Metabolism Cytoskeleton Electric Cell-Substrate Impedance Sensing
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Measurement of Metastatic Potential using ECIS™ BioTechniques, October 2002 Keese, Bhawe, Wegener and Giaever
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The basis of the metastatic assay
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The Dunning prostatic adenocarcinoma series was developed at Johns Hopkins and consists of several cell sublines. These all have their origin in a single line isolated from a prostatic tumor. After extensive passaging and mutagenesis, several distinct sublines were isolated having different in vivo metastatic abilities. Six of these lines were used in our studies.
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To carry out the metastatic assay, first a layer of endothelial cells is established Confluence verified
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Challenge of HUVEC cell layers with weakly (G) and highly metastatic (AT3) cell lines Challenge highly metastatic
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Confluent HUVEC layer No cells MLL Challenge 10 5 cells/cm 2
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Prostatic cell challenge
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Signal Transduction
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[Ca 2+ ] Alterations in the cytoskeleton G Protein Coupled Receptor
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CHO cells engineered to over- express the muscarinic receptor exposed to the agonist carbachol EC 50 = ~1 M
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The effect of carbachol is blocked by the antagonist pirenzipine (PZP )
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Treatment of CHO-M1T cells with carbachol Data analysis using the ECIS model morphological information
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Similar results are obtained with the beta adrenergic receptor
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The Dynamics of Cell Spreading
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WI-38 VA/13 cells Cell inoculation 10 5 cells/cm 2 Electrodes were pre- coated with different layers of adsorbed protein before cell inoculation Adsorbed proteins alter cell spreading dynamics
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MDCK II cells inoculated on electrodes pre-coated with various proteins FN fibronectin LAM laminin VN vitronectin BSA bovine serum albumin BSA FN Inoculation Confluent Cell-free Capacitance at high freq. measures the open (cell- free) electrode area
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Adsorb BSA re-inoculate with MDCK cells after 24 hours remove cell MDCK cells BSA is adsorbed to the electrodes and they are inoculated with MDCK cells
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Adsorb BSA re-inoculate with MDCK cells after 24 hours remove cell MDCK cells Laminin-like response
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MDCK cells inoculated on fibronectin-coated electrodes with different concentrations of synthetic tetrapeptide RGDS present
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MDCK cells inoculated on laminin-coated electrodes with different concentrations of synthetic tetrapeptide RGDS present
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Elevated Field Applications 1 Electroporation 2 Wound healing assay
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Elevated Field Applications 1 Electroporation 2 Wound healing assay
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NORMAL MODE 1 MICROAMP, 10 MILLIVOLTS ELEVATED FIELD 1 MILLIAMP, A FEW VOLTS pore formation Elevated current applied ~200msec
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500 msec200 msec100 msec50 msec Variation of the pulse duration: Lucifer yellow uptake Pulse:40 kHz 4.0 V MDCK Type II cells Variation of the pulse duration: Lucifer yellow uptake Pulse:40 kHz 4.0 V MDCK Type II cells
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Uptake of dyes with different molecular weight Lucifer Yellow M = 0.5 kDa TRITC-dextran M = 76 kDa Pulse:40 kHz, 4.0 V, 200 msec FITC-dextran M = 250 kDa Albany Medical College (F. Minnear) has demonstrated introduction of DNA constructs using the method and obtained expression of GFP
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bleomycin only bleomycin with electroporation High field pulse for 100 msec Electroporated control Electroporation of bleomycin into HUVEC monolayers
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Wound Healing (migration) Assay
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Traditional Wound Healing Assay Problems of reproducibility and quantification Cell migration
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500 msec200 msec100 msec50 msec Variation of the pulse duration: Lucifer yellow uptake Pulse:40 kHz 4.0 V MDCK Type II cells Cell death
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NORMAL MODE 1 MICROAMP, 10 MILLIVOLTS ELEVATED FIELD 1 MILLIAMP, A FEW VOLTS Severe pore formation localized heating Elevated current applied 15 seconds CELL WOUNDING
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NRK Cells Prior to Wounding
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NRK Cells Immediately after Wounding
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NRK Cells During Healing
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NRK Cells After Healing
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Confluence Open electrode RPI
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BSC-1 cells NRK cells wounding
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Phase Contrast Microscopy of MDCK Cell Wounding CONTROL WOUNDED20 HOURS LATER Are the cells killed, or are they simply damaged and recovering?
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Calcein-AM and Ethidium Staining Control3 V, 10 sec
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BSC-1 cells wounded on different size electrodes Standard 250 micron diameter electrode wound
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BSC-1 cells wounded on different size electrodes 100 microns wound
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BSC-1 cells wounded on different size electrodes 50 microns wound
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BSC-1 cells wounded on different size electrodes Lag period migration = ~17 microns/hr
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Phase Contrast Microscopy of MDCK Cell Wounding CONTROL WOUNDED20 HOURS LATER
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Initial wound Re-wound The approach is highly reproducible
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New directions Flow cell for endothelial cell studies 96 well Format for HTS
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ECIS 9600
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ECIS Flow System
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Acknowledgements: Ivar Giaever President of Applied BioPhysics and Institute Professor at Rensselaer Joachim Wegener Sarah Walker, Kaumudi Bhawe, Steve Tet, Will Wu, Lali Reddy, Paramita Ghosh, Guo Chen, Narayan Karra Funding from: NIH SBIR Program NCRR NCI NIEHS National Foundation for Cancer Research
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www.biophysics.com
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