Micropipet-Assisted Formation of Microscopic Networks of Unilamellar Lipid Bilayer Nanotubes and Containers

Karlsson, Mattias; Sott, Kristin; Cans, Ann-Sofie; Karlsson, Anders; Karlsson, Roger; Orwar, Owe

doi:10.1021/la0108611

Cited by 104 publications

(173 citation statements)

References 32 publications

(50 reference statements)

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“…Fabrication of unilamellar networks of nanotube-interconnected liposomes was performed as described in ref. 36. High-graduation micromanipulators (MWH-3; Narishige) allowed precise control of vesicle immobilization in the x-y-z position.…”

Section: Methodsmentioning

confidence: 99%

Controlling the rates of biochemical reactions and signaling networks by shape and volume changes

Lizana

Bauer

Orwar

2008

Proc. Natl. Acad. Sci. U.S.A.

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In biological systems, chemical activity takes place in micrometerand nanometer-sized compartments that constantly change in shape and volume. These ever-changing cellular compartments embed chemical reactions, and we demonstrate that the rates of such incorporated reactions are directly affected by the ongoing shape reconfigurations. First, we show that the rate of product formation in an enzymatic reaction can be regulated by simple volume contraction-dilation transitions. The results suggest that mitochondria may regulate the dynamics of interior reaction pathways (e.g., the Krebs cycle) by volume changes. We then show the effect of shape changes on reactions occurring in more complex and structured systems by using biomimetic networks composed of micrometer-sized compartments joined together by nanotubes. Chemical activity was measured by implementing an enzymatic reaction-diffusion system. During ongoing reactions, the network connectivity is changed suddenly (similar to the dynamic tube formations found inside Golgi stacks, for example), and the effect on the reaction is registered. We show that spatiotemporal properties of the reaction-diffusion system are extremely sensitive to sudden changes in network topology and that chemical reactions can be initiated, or boosted, in certain nodes as a function of connectivity.

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Section: Methodsmentioning

confidence: 99%

Controlling the rates of biochemical reactions and signaling networks by shape and volume changes

Lizana

Bauer

Orwar

2008

Proc. Natl. Acad. Sci. U.S.A.

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“…Such lipidbased networks can be prepared with designed connectivity, geometry, topology, and dimensionality, and their contents and surface properties can be controlled as described (15)(16)(17)(18)(19)(20)(21). These in vitro-fabricated networks are of the same amphiphilic and self-assembling nature as nanotubes found in vivo, and with similar dimensions regarding both radii (50-150 nm) (1) and lengths (up to tens of m).…”

mentioning

confidence: 99%

Single-file electrophoretic transport and counting of individual DNA molecules in surfactant nanotubes

Tokarz

Åkerman

Olofsson

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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We demonstrate a complete nanotube electrophoresis system (nanotube radii in the range of 50 to 150 nm) based on lipid membranes, comprising DNA injection, single-molecule transport, and single-molecule detection. Using gel-capped electrodes, electrophoretic single-file transport of fluorescently labeled dsDNA molecules is observed inside nanotubes. The strong confinement to a channel of molecular dimensions ensures a detection efficiency close to unity and identification of DNA size from its linear relation to the integrated peak intensity. In addition to constituting a nanotechnological device for identification and quantification of single macromolecules or biopolymers, this system provides a method to study their conformational dynamics, reaction kinetics, and transport in cell-like environments.electrophoresis ͉ lipid ͉ conformation C ontrolled transport, interrogation, and manipulation of single molecules in integrated nanoscale devices would provide new tools for fundamental studies of molecular properties, development of ultrasensitive biochemical assays, and new models for studies of transport and reaction phenomena in confined biological systems. For example, it was recently shown that lipid bilayer nanotubes Ϸ50-200 nm in diameter are involved in mediated transport of water-soluble and membrane-bound components between cells (1). Such observations do not only raise important questions about transport mechanisms for macromolecules and organelles in spaces comparable to the size of the cargo itself, but also about how such strong confinement affects diffusion, conformation, and chemical reactions of enclosed molecules and particles (2-4). Furthermore, along with previous understanding of sorting and routing of individual molecules, e.g., in the Golgi-endoplasmic reticulum network (5, 6), these observations point out clearly that what has been an engineering dream for decades, i.e., to create manmade devices that can operate with single molecules in a controlled fashion, is a reality in biology and therefore can be a reality in the world of engineering provided that we procure sufficient knowledge and tools to emulate these systems. However, experimental systems for controlled confinement and transport of materials dissolved in fluids approaching the theoretical size limit, i.e., where the ratio of channel inner diameter and dimensions of the cargo are close to unity, have been difficult to make in combination with transport control. This difficulty is mainly because these systems have been fabricated by using solid-state materials and processing technologies used in the computer industry that are limited in terms of the smallest accessible length scales, topologies, materials properties, complexity of fabrication, and their necessary integration to large-scale instrumentation to drive fluid flow. Nonetheless, powerful micro͞nanofluidic protocols for polymer transport in solid-state nanochannels and pores (7-12) as well as in polydimethylsiloxane channels of a few micrometers in diameter (13, 14) have be...

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“…Various experimental techniques are now available to control the geometry, dimensionality, topology, and functionality in surfactant membranes (12)(13)(14)(15)(16)(17)(18)(19). Methods based on self-assembly, selforganization, forced shape transformations, and micromanipulation are used to form synthetic or semisynthetic enclosed lipid bilayer structures with some properties similar to biological compartments.…”

Section: Forming Nanotube-vesicle Networkmentioning

confidence: 99%

“…Our lab and other groups have developed concepts and protocols for producing nanoscale devices and networks based on spontaneous and forced shape transitions in lipid bilayer membranes or other soft materials (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). The networks consist of surface-immobilized vesicles (~5-50-µm diam) conjugated by nanotubes (50 -150-nm radius).…”

mentioning

confidence: 99%

Chemical Analysis in Nanoscale Surfactant Networks

Karlsson¹,

Ewing²,

Dommersnes³

et al. 2006

Anal. Chem.

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A lthough the "hard matter" physical sciences (e.g., microelectronics) and the "soft matter" biological sciences (e.g. cell biology and molecular biology) are two distinct areas of research, they are now progressively being combined to create new systems and devices with applications in analytical chemistry. Miniaturization is one of the important factors here: A major goal is to create devices that can operate with high sensitivity and resolution on length scales and time frames relevant to single-molecule studies. Using top-down strategies to fabricate ultrasmall structures is technologically challenging. Therefore, new bottom-up methods of nanoscale fabrication based on self-assembly and self-organization of biological or biomimetic materials are constantly being developed (1-6). The type of nanoscale engineering described in this article has, at least partly, been derived from our growing understanding of living cells, where many nanomechanical and chemical operations are based on controlled shape transitions in surfactant bilayer membranes that also carry proteins to support important functions. Biological cells have a staggering ability to parallel-process multiple chemical reactions and physical (e.g., transport) processes in nanometer-sized systems and to perform a great number of tasks based on single-molecule processes. Thus, nature has solved many engineering problems on small length scales and achieved truly nanoscale, complex chemical devices that can be used for computational, biophysical, synthetic, and analytical applications (7-11). The philosophy behind the work reviewed here is to produce human-made, biomimetic systems that imitate some key features of small biological systems with the overall goal of providing micro-and nanoscale devices that can perform complex chemical operations.

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Micropipet-Assisted Formation of Microscopic Networks of Unilamellar Lipid Bilayer Nanotubes and Containers

Cited by 104 publications

References 32 publications

Controlling the rates of biochemical reactions and signaling networks by shape and volume changes

Controlling the rates of biochemical reactions and signaling networks by shape and volume changes

Single-file electrophoretic transport and counting of individual DNA molecules in surfactant nanotubes

Chemical Analysis in Nanoscale Surfactant Networks

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