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Your search keyword '"Boukany, Pouyan E."' showing total 196 results
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196 results on '"Boukany, Pouyan E."'

1. Cell spheroid viscoelasticity is deformation-dependent

Author

Boot, Ruben C., van der Net, Anouk, Gogou, Christos, Mehta, Pranav, Meijer, Dimphna H., Koenderink, Gijsje H., and Boukany, Pouyan E.

Subjects
Condensed Matter - Soft Condensed Matter, Quantitative Biology - Tissues and Organs
Abstract

Tissue surface tension influences cell sorting and tissue fusion. Earlier mechanical studies suggest that multicellular spheroids actively reinforce their surface tension with applied force. Here we study this open question through high-throughput microfluidic micropipette aspiration measurements on cell spheroids to identify the role of force duration and cell contractility. We find that larger spheroid deformations lead to faster cellular retraction once the pressure is released, regardless of the applied force and cellular contractility. These new insights demonstrate that spheroid viscoelasticity is deformation-dependent and challenge whether surface tension truly reinforces.

Published
2024

2. Interstitial flow potentiates TGF-$\beta$/Smad-signaling activity in lung cancer spheroids in a 3D-microfluidic chip

Author

Rahman, Zaid, Bordoloi, Ankur Deep, Rouhana, Haifa, Tavasso, Margherita, Garbin, Valeria, Dijke, Peter ten, and Boukany, Pouyan E.

Subjects
Physics - Biological Physics
Abstract

Within the tumor microenvironment (TME), cancer cells use mechanotransduction pathways to convert biophysical forces to biochemical signals. However, the underlying mechanisms and functional significance of these pathways remain largely unclear. The upregulation of mechanosensitive pathways from biophysical forces such as interstitial flow, leads to the activation of various cytokines, most importantly transforming growth factor-$\beta$ (TGF-$\beta$). TGF-$\beta$ is a critical inducer of epithelial-mesenchymal transition (EMT) in cancer cells that leads to increased cell motility and invasion in a Smad dependent manner. Current research models have limited ability to investigate the combined effects of biophysical forces (such as interstitial flow) and cytokines (TGF-$\beta$) in a 3D microenvironment. We used a 3D-matrix based microfluidic platform to demonstrate the potentiating effect of interstitial flow (IF) on exogenous TGF-$\beta$ induced upregulation of the Smad-signaling activity and the expression of mesenchymal marker vimentin in A549 lung cancer spheroids. To monitor this, we used stably integrated fluorescent based reporters into the A549 cancer cell genome. Our results demonstrate that interstitial flow enhances exogenous TGF-$\beta$ induced Smad-signaling activity in lung cancer spheroids embedded in a matrix microenvironment. In addition, we observed an increased cell motility for A549 spheroids when exposed to interstitial flow and TGF-$\beta$. Our 3D-microfluidic model integrated with real-time imaging provides a powerful tool for investigating cancer cell signaling and motility associated with invasion characteristics in a physiologically relevant TME.

Published
2023

29. Actin networks regulate the cell membrane permeability during electroporation

Author

Muralidharan, Aswin, Rems, Lea, Kreutzer, Michiel T, Boukany, Pouyan E, Muralidharan, Aswin, Rems, Lea, Kreutzer, Michiel T, and Boukany, Pouyan E

Abstract

Transient physical disruption of cell membranes by electric pulses (or electroporation) has significance in biomedical and biological applications requiring the delivery of exogenous (bio)molecules to living cells. We demonstrate that actin networks regulate the cell membrane permeability during electroporation. Disruption of actin networks increases the uptake of membrane-impermeable molecules such as propidium iodide during electroporation. Our experiments at different temperatures ranging from 11 °C to 37 °C show that molecular uptake during electroporation increases with temperature. Furthermore, by examining the temperature-dependent kinetics of propidium iodide uptake, we infer that the activation energy barrier of electroporation is lowered when the actin networks are disrupted. Our numerical calculations of transmembrane voltage show that the reduced activation energy barrier for the cells with disrupted actin is not a consequence of the changes in transmembrane voltage associated with changes in the cell shape due to the disruption of actin, indicating that this could be due to changes in membrane mechanical properties. Our results suggest that the current theoretical models of electroporation should be advanced further by including the contributions of the cytoskeletal networks on the cell membrane permeability during the delivery of exogenous materials., QC 20201020

Published
2020
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30. DNA-membrane complex formation during electroporation is DNA size-dependent

Author

Sachdev, Shaurya, Feijoo Moreira, Sara, Keehnen, Yasmine, Rems, Lea, Kreutzer, Michiel T., Boukany, Pouyan E., Sachdev, Shaurya, Feijoo Moreira, Sara, Keehnen, Yasmine, Rems, Lea, Kreutzer, Michiel T., and Boukany, Pouyan E.

Abstract

Size of DNA molecules governs their interaction with the cell membrane during electroporation and their subsequent transport inside the cell. In order to investigate the effect of DNA size on DNA-membrane interaction during electroporation, cells are electro-pulsed with DNA molecules; 15 bp, 25 bp, 50 bp, 100 bp and 1000 bp (bp = base pairs). Within the experimental parameter space, DNA-membrane complexes or DNA aggregates are observed at the cell membrane for DNA molecules containing 25 or more base pairs. No aggregates are observed for DNA molecules containing 15 bp. For all DNA sizes, direct access to the cytoplasm is observed, however the amount translocated decays with the size. The observed dependency of DNA aggregate formation on the size of the DNA molecules is consistent with the Onsager's theory of condensation of anisotropic rod-like molecules., QC 20201118

Published
2020
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36. DNA translocation to giant unilamellar vesicles during electroporation is independent of DNA size

Author

Sachdev, Shaurya, Muralidharan, Aswin, Choudhary, Dipendra K., Perrier, Dayinta L., Rems, Lea, Kreutzer, Michiel T., Boukany, Pouyan E., Sachdev, Shaurya, Muralidharan, Aswin, Choudhary, Dipendra K., Perrier, Dayinta L., Rems, Lea, Kreutzer, Michiel T., and Boukany, Pouyan E.

Abstract

Delivery of naked DNA molecules into living cells via physical disruption of the membrane under electric pulses has potential biomedical applications ranging from gene electro-transfer, electro-chemotherapy, to gene therapy, yet the mechanisms involved in DNA transport remain vague. To investigate the mechanism of DNA translocation across the cell membrane, giant unilamellar vesicles (GUVs) were electroporated in the presence of DNA molecules keeping the size of the DNA molecules as a variable parameter. We experimentally determined the translocation efficiency for each size of the DNA molecule, to compare the results with the existing and conflicting theories of the translocation mechanism i.e. stochastic threading and bulk electrophoresis. We observed that the translocation efficiency is independent of DNA size (ranging from 25-20 000 bp, bp = base pairs), implying that DNA molecules translocate freely across the electro-pores in the lipid membrane in their native polymer conformation, as opposed to unravelling and threading through the electro-pore. Bulk electrophoretic mobility determines the relationship between translocation efficiency and the size of the DNA molecule. This research provides experimental evidence of the mechanistic understanding of DNA translocation across lipid membranes which is essential for devising efficient and predictable protocols for electric field mediated naked DNA delivery., QC 20200122

Published
2019
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