Physics of living systems
Living cells cannot be clearly classified as liquid, solid, or anything in between because they are active systems that can dramatically change their properties via internally generated forces. This motivates the need to develop a new approach to understand the fundamental physics of living systems. My research focuses on defining biological cells as a new state-of-matter that exists only far-from-equilibrium. I believe this approach will help us understand the driving forces of life at the cellular-scale and define metabolic rate from a physical persective. To this end, we developed a combined microscope and optical tweezer system to measure nonequilibrium force fluctuations in living cells. This experimental apparatus will allow a new class of biophysical measurements.
Our research interests are primarily in the field of the physics of living systems at the microscopic scale. This field is at the intersection of physics, biology, and material science and seeks to shed new light on cell biological processes and create new forms of “living” matter with life-like properties. Our goal is to understand the basic physics underlying biological processes that make living things different from non-living. To quantify these biophysical systems we use optical microscopy, laser tweezers, high-speed imaging, and microfluidic devices.
Fodor, É., Ahmed, W. W., Almonacid, M., Bussonnier, M., Gov, N. S., Verlhac, M. H., ... & van Wijland, F. (2016). Nonequilibrium dissipation in living oocytes. EPL (Europhysics Letters), 116(3), 30008.
Ahmed, W. W., Fodor, É., & Betz, T. (2015). Active cell mechanics: Measurement and theory. Biochimica et Biophysica Acta (BBA)-Molecular Cell Research, 1853(11), 3083-3094.
Ahmed, W. W., & Betz, T. (2015). Dynamic cross-links tune the solid–fluid behavior of living cells. Proceedings of the National Academy of Sciences, 112(21), 6527-6528.
Almonacid, M., Ahmed, W. W., Bussonnier, M., Mailly, P., Betz, T., Voituriez, R., ... & Verlhac, M. H. (2015). Active diffusion positions the nucleus in mouse oocytes. Nature cell biology, 17(4), 470.
Ahmed, W. W., & Saif, T. A. (2014). Active transport of vesicles in neurons is modulated by mechanical tension. Scientific reports, 4.
Ahmed, W. W., Williams, B. J., Silver, A. M., & Saif, T. A. (2013). Measuring nonequilibrium vesicle dynamics in neurons under tension. Lab on a Chip, 13(4), 570-578.