Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: A : Schematic diagram comparing standard ECIS vs. PM-ECIS electrodes, electrode thickness not to scale. Schematic created using BioRender. B: Fabrication of microfluidic device incorporating porous membrane (PM-ECIS) electrodes. C: Top-down view of device with integrated PM-ECIS) electrodes. D: Resistance at 4 kHz for HUVECs seeded at t=0 on working electrodes of various sizes (d = 250, 500, 750 μm). Resistance values for corresponding cell-free control electrodes shown for comparison. DS tape = double-sided tape.

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques: Membrane, Control, Comparison

Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: A : Measurement setup for ECIS resistance and chopstick TEER. Schematic created using BioRender B: Resistance values at 4 kHz for devices with collagen gel in bottom channel vs. control for ECIS and TEER, respectively, at Day 1, N= 2-4 per condition. Unpaired t-test, * p < 0.01. C: Change in resistance values at 4 kHz for devices with collagen gel in bottom channel vs. medium-only control at 2 hours post-polymerization (t=2.5 h) for various working electrode diameters (Δ R = R 2h post-polymerization – R baseline ); N=3-5 per condition. No significant difference between control and collagen conditions (p=0.44 by one-way ANOVA). Data presented as mean ± standard deviation.

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques: Control, Standard Deviation

Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: A: Schematic of blood-brain barrier (BBB) co-culture setup, with HBMEC in top channel and primary human astrocytes (AC) in bottom channel. Schematic created using BioRender. B, C: Fluorescence microscopy imaging from top side, showing HBMEC cell layer on counter electrode surface (black), and AC embedded in hydrogel underneath . D, E: Confocal imaging of BBB co-culture in microfluidic setup from astrocyte side of membrane. Dotted line indicates border between working electrode and membrane. AC stained for GFAP (green), HBMEC stained for ZO-1 (pink) and nuclei visualized with Hoechst 33342. F: ECIS measurements of BBB co-culture over 5 days in static condition, showing traces for three different co-culture devices. Cell seeding occurred at t=0; black arrows = media changes. Mean ± SD plotted for N=3 independent electrodes (d=500 µm) for co-culture condition.

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques: Co-Culture Assay, Fluorescence, Microscopy, Imaging, Membrane, Staining

Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: A: Resistance values measured at 4 kHz in blank devices filled with PBS before (static) and after application of fluid flow at 1.3 mL/min (equivalent to a wall shear stress of 5 dyn/cm 2 ). B: No significant differences between pre-flow and post-flow values for any of the electrode sizes (Δ R = R post-flow – R pre-flow ). C, D: Frequency scan showing impedance values across scanned frequencies ( C ), and resistance ( D ). N=3-4 for each electrode size, data presented as mean ± standard deviation.

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques: Shear, Standard Deviation

Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: A: Live fluorescence imaging of GFP-expressing HUVECs perfused for up to 5 days confirming viability and adherence of cells to porous membrane and electrodes vs. cells grown under static conditions for the same duration B, C: Immunostaining for ZO-1 and VE-cadherin and imaging with confocal microscopy confirms presence of confluent monolayer on working electrodes ( B ), and counter electrodes ( C ).

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques: Fluorescence, Imaging, Expressing, Membrane, Immunostaining, Confocal Microscopy

Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: A: Left: Impedance measured at 40 kHz over 5 days of culture, 3 days of perfusion. Mean ± SD plotted for N=3 electrodes per condition, d = 750 µm. Stars indicate timepoints for impedance comparisons. Right: Comparison of impedance measured immediately before starting perfusion culture, minimum impedance value reached following start of perfusion, impedance after 1.5 days of flow, and 3 days of flow (Δ Z = Z timepoint – Z pre-cell seeding baseline , similar calculation for resistance). B: Impedance at 40 kHz, d = 500 µm C: d = 250 µm; N=2-3 electrodes per condition. Mean ± SD plotted where applicable; for time intervals with N=2, individual replicates shown. D, E, F: Resistance measured at 4 kHz over 5 days of culture, 3 days of perfusion. Mean ± SD plotted for N=3 electrodes per condition, d = 750 µm ( D ), 500 µm ( E ), 250 µm ( F ). Cell seeding at t=0; black inverted triangle indicates manual media change on Day 1; † = syringes refilled with culture medium. Unpaired t-test, * = p<0.05, ** = p<0.01, *** = p<0.001. Data presented as mean ± standard deviation.

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques: Comparison, Standard Deviation

Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: A: Decrease in resistance at 4 kHz after induction of flow (t=0) relative to static control. ΔR = R flow – R static for time point corresponding to post-flow minimum for each electrode. † p < 0.05, †† p<0.01 by one-sample t-test relative to change in ΔR=0; ** p < 0.01, *** p < 0.001 by one-way ANOVA with Bonferroni test. B, C, D: Resistance values for static and flow conditions over time up until post-flow minimum ( left ) and t = 3 hours ( right ) for 750 µm ( B ), 500 µm ( C ), 250 µm ( D ) electrodes. p < 0.05, ** p < 0.01 by unpaired t-test. N = 3 for each electrode size for each condition. Data presented as mean ± standard deviation.

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques: Control, Standard Deviation

Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: Resistance at 4 kHz for HBMEC + primary human astrocyte co-culture vs. cell-free control, graphs showing example electrodes from different experiments.

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques: Co-Culture Assay, Control

Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: A: Impedance measured at 40 kHz and B: resistance measured at 4 kHz over 7 days of culture, 5 days of perfusion, corresponding to 250 µm working electrode shown in . Cell seeding at t=0; black inverted triangle indicates manual media change on Day 1; † = syringes refilled with culture medium.

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques:

Journal: bioRxiv

Article Title: A microfluidic platform with integrated porous membrane cell-substrate impedance spectroscopy (PM-ECIS) for biological barrier assessment

doi: 10.1101/2023.11.25.568615

Figure Lengend Snippet: Resistance at 4 kHz measured over time for A : 750 µm, B : 500 µm, and C : 250 µm working electrodes. Cell seeding at t=0.

Article Snippet: The classic setup uses a single small, circular (d=250 μm) sensing electrode and a large counterelectrode integrated onto the bottom of a well plate, though various configurations are available from Applied Biophysics, including interdigitated electrodes and flow arrays for studying the effect of fluid shear .

Techniques: