A MEMS actuator and sensor for the study of cell mechanics and adhesion
Abstract/Contents
- Abstract
- An active area of Microelectromechanical Systems (MEMS) research over the past few years has been to develop tools that can probe the forces generated and sensed by cells. Silicon-based tools developed in this effort have the benefit of being able to apply and sense forces at a greater resolution and in a more repeatable fashion. However, they have been too small to probe more than one or a few cells at a time, and the opaqueness of silicon has prohibited inverted live microscopy, which is important for transferring the technology to biological and medical labs. In addition, while many tools exist that can apply and sense the effects of tension on cells, no devices exist that can apply shear to a sheet of epithelial cells. This is despite the fact that the ability to apply and sense shear is important in understanding how cells interact with each other mechanically, which is essential in studying cell-cell adhesions in biology and medicine. Two types of silicon MEMS devices have been designed, fabricated, and tested, which can strain a sheet of epithelial (2D and skin-like) cells in tension and shear simultaneously. The first set of devices, which have silicon cell-adhesion pads can be used for upright bright-field and fluorescence microscopy. The second set of devices, which have silicon-nitride cell-adhesion pads can be used for both upright and inverted bright-field and fluorescence microscopy. Inverted microscopy has been made possible by spraying the bottom of 50 \um\ deep trenches with photoresist and exposing the area in the shape of cell-adhesion pads. In addition, the Silicon on Insulator (SOI) handle wafer has been backside etched below the cell-adhesion pads. These devices have been integrated with a cell-delivery mechanism that can deliver ~1000 cells to the cells adhesion pads. In addition, an open culture system has been implemented that allows the user to perform live cell microscopy for days without the use of an incubator. With the combination of these devices and experimental methods we have formed single sheets of Madin-Darby Canine Kidney (MDCK) epithelial cells on these devices and observed their reorganization in response to shear and tension. Particle Image Velocimetry (PIV) shows cells in an epithelium move towards the shear plane in response to an applied shear stress. Experiments where blebbistatin, a treatment inhibiting actomyosin contractility, was applied before the application of stress showed no collective cell migration. Therefore, we showed that the collective migration due to shear is an active biological response, as opposed to a passive and purely material one.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2016 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Sadeghipour, Ehsan |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering. |
| Primary advisor | Pruitt, Beth |
| Thesis advisor | Pruitt, Beth |
| Thesis advisor | Howe, Roger Thomas |
| Thesis advisor | Nelson, W. J. (W. James) |
| Advisor | Howe, Roger Thomas |
| Advisor | Nelson, W. J. (W. James) |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Ehsan Sadeghipour. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2016. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2016 by Ehsan Sadeghipour
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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