Mixing Water, Transducing Energy, and Shaping Membranes: Autonomously Self-Regulating Giant Vesicles
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- 作者：James C. S. Ho ; Padmini Rangamani ; Bo Liedberg ; Atul N. Parikh
- 刊名：Langmuir
- 出版年：2016
- 出版时间：March 8, 2016
- 年：2016
- 卷：32
- 期：9
- 页码：2151-2163
- 全文大小：710K
- 年卷期：James C. S. Ho is a research fellow in the School of Materials Science & Engineering at Nanyang Technological University (NTU). He received his B.Sc. degree in biological sciences from NTU (2009) and Ph.D. degree in medical science (2014) from Lund University. His research interest lies at the interface of cell biology, structural biology, and lipid membrane dynamics and associated processes, with a focus on osmoregulation in artificial vesicles and cellular systems, biosensing platforms, and alternative cancer cell death mechanisms.Padmini Rangamani is an assistant professor in mechanical engineering at the University of California—San Diego. Previously, she was a UC Berkeley Chancellor’s Postdoctoral Fellow, where she worked on lipid bilayer mechanics (2010–2014). She obtained her Ph.D. in biological sciences from the Icahn School of Medicine at Mount Sinai (2010). She received her B.S. (2001) and M.S. (2005) in chemical engineering from Osmania University (Hyderabad, India) and Georgia Institute of Technology, respectively. Her research interests include the regulation of cell shape through membrane dynamics, actin cytoskeleton remodeling, and mathematical modeling of biological processes.Bo Liedberg is a full professor of materials science, director of the Center for Biomimetic Sensor Science (CBSS), and Dean of the Interdisciplinary Graduate School (IGS) at Nanyang Technological University (NTU). He received his Ph.D. degree in applied physics (1986) from Linköping University. His basic research is primarily devoted to soft materials science including plasmonics, surface chemistry, self-assembly, and biomimetics. He is also interested in developing new biosensing tools in biology and medicine and exploiting novel transduction principles for biochemical sensing and biomedical diagnostics.Atul N. Parikh is a professor of biomedical engineering and of chemical engineering and materials science at the University of California—Davis. Since 2012, he has also served as a visiting professor in the School of Materials Science & Engineering at NTU. He received his B. Chem. Eng. (1987) degree from the University of Bombay (UDCT) and his Ph.D. degree (2004) from the Department of Materials Science & Engineering at The Pennsylvania State University. Earlier, he was a postdoctoral scholar and then a technical staff member in the Chemical Science and Bioscience divisions at Los Alamos National Laboratory from 1996 to 2001. His current research includes fundamental studies of dynamic self-assembly, active interfaces, and physical compartmentalization in soft and living material systems.
- ISSN：1520-5827
文摘
Giant lipid vesicles are topologically closed compartments bounded by semipermeable flexible shells, which isolate femto- to picoliter quantities of the aqueous core from the surrounding bulk. Although water equilibrates readily across vesicular walls (10–2–10–3 cm3 cm–2 s–1), the passive permeation of solutes is strongly hindered. Furthermore, because of their large volume compressibility (∼109–1010 N m–2) and area expansion (102–103 mN m–1) moduli, coupled with low bending rigidities (10–19 N m), vesicular shells bend readily but resist volume compression and tolerate only a limited area expansion (∼5%). Consequently, vesicles experiencing solute concentration gradients dissipate the available chemical energy through the osmotic movement of water, producing dramatic shape transformations driven by surface-area–volume changes and sustained by the incompressibility of water and the flexible membrane interface. Upon immersion in a hypertonic bath, an increased surface-area–volume ratio promotes large-scale morphological remodeling, reducing symmetry and stabilizing unusual shapes determined, at equilibrium, by the minimal bending-energy configurations. By contrast, when subjected to a hypotonic bath, walls of giant vesicles lose their thermal undulation, accumulate mechanical tension, and, beyond a threshold swelling, exhibit remarkable oscillatory swell–burst cycles, with the latter characterized by damped, periodic oscillations in vesicle size, membrane tension, and phase behavior. This cyclical pattern of the osmotic influx of water, pressure, membrane tension, pore formation, and solute efflux suggests quasi-homeostatic self-regulatory behavior allowing vesicular compartments produced from simple molecular components, namely, water, osmolytes, and lipids, to sense and regulate their microenvironment in a negative feedback loop.