Lipid-Based Passivation in Nanofluidics

Persson, Fredrik; Fritzsche, Joachim; Mir, Kalim U.; Modesti, Mauro; Westerlund, Fredrik; Tegenfeldt, Jonas O.

doi:10.1021/nl204535h

Cited by 88 publications

(104 citation statements)

References 25 publications

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“…However, for more practical use and realization of the full potential of these systems, we must now integrate these elements into functional devices, solve the lipid bilayer stability issues caused by the structural fragility of SLB in harsh conditions (such as dehydration and high salt concentration) and address nonspecific binding, especially for biosensing and cell-interfacing applications. 88,89 Furthermore, incorporating functional proteins such as transmembrane proteins into a lipid layer in an in vivo-like configuration while sustaining their functionalities is highly difficult. Finally, current techniques for generating nanoscale cell membrane features are mostly based on the creation of single heterogeneous membrane structures.…”

Section: Discussionmentioning

confidence: 99%

Lipid-nanostructure hybrids and their applications in nanobiotechnology

Lee

Nam

2013

NPG Asia Mater

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Cell membranes contain a variety of lipids and functional proteins that offer active platforms that organize the membrane components into functional assemblies and perform biologically important reactions. The dynamic and complex nature of the membranes makes them attractive materials, but at the same time, researchers report substantial experimental uncertainty in controlling the membrane reactions and extracting valuable information. The fascinating new structures and properties of nanomaterials could be utilized in addressing aforementioned issues, and the design and synthesis of lipid-nanostructure hybrids could be beneficial to the research areas in lipid-membrane biotechnology and nanobiotechnology. These hybrid structures possess dimensions that are comparable to that of biological molecules and structures and physicochemical properties that arise from both lipids and nanomaterials. Therefore, lipid-nanostructure hybrids offer additional options for control of the synthesized structures, provide new insight in understanding nanostructures and biological systems and allow the mimicking of functional subcellular membrane components and monitoring of the membrane-associated reactions in a highly sensitive and controllable manner. In this review, we present recent advances in the synthesis of various lipid-nanostructure hybrids and the application of these structures in biotechnology and nanotechnology. We further describe the scientific and practical applications of lipid-nanostructure hybrids for detecting membrane-targeting molecules, interfacing nanostructures with live cells and creating membrane-mimicking platforms to investigate various intercellular processes.

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Section: Discussionmentioning

confidence: 99%

Lipid-nanostructure hybrids and their applications in nanobiotechnology

Lee

Nam

2013

NPG Asia Mater

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“…Recently, several groups have used nanofluidic channels to investigate the physical properties of nanoconfined DNA-protein complexes [12][13][14][15][16] and for optical mapping of single DNA molecules [17][18][19][20][21] .…”

Section: Introductionmentioning

confidence: 99%

Nanoconfined Circular and Linear DNA: Equilibrium Conformations and Unfolding Kinetics

Alizadehheidari¹,

Werner

Noble³

et al. 2015

Macromolecules

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Studies of circular DNA confined to nanofluidic channels are relevant both from a fundamental polymer-physics perspective and due to the importance of circular DNA molecules in vivo. We here observe the unfolding of DNA from the circular to linear configuration as a light-induced double strand break occurs, characterize the dynamics, and compare the equilibrium conformational statistics of linear and circular configurations. This is important because it allows us to determine to which extent existing statistical theories describe the extension of confined circular DNA. We find that the ratio of the extensions of confined linear and circular DNA configurations increases as the buffer concentration decreases. The experimental results fall between theoretical predictions for the extended de Gennes regime at weaker confinement and the Odijk regime at stronger confinement. We show that it is possible to directly distinguish between circular and linear DNA molecules by measuring the emission intensity from the DNA. Finally, we determine the rate of unfolding and show that this rate is larger for more confined DNA, possibly reflecting the corresponding larger difference in entropy between the circular and linear configurations.

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“…The coating procedure is described in detail elsewhere. 18 The filaments were imaged using an epifluorescence microscope (Zeiss AxioObserver.Z1) equipped with a Photometrics Evolve EMCCD camera and a 100× oil immersion TIRF objective (NA = 1.46) from Zeiss. Using the software AxioVision, 200 subsequent images were recorded with an exposure time of 20 ms and an interval between the images of 30 ms.…”

Section: +mentioning

confidence: 99%

“…This problem was recently solved by passivating the negatively charged silica surface of the nanochannels with a zwitterionic lipid bilayer. 17,18 Using lipid passivation, the physical properties of the bacterial recombination protein RecA, which forms micrometer-long nucleoprotein filaments around DNA, were studied. 15 The persistence length of the RecA-DNA filament could be determined by using nanochannels with dimensions corresponding to the Odijk regime, 19 in which the polymer is confined to so very narrow dimensions that it cannot fold back on itself.…”

Section: ■ Introductionmentioning

confidence: 99%

Visualizing the Nonhomogeneous Structure of RAD51 Filaments Using Nanofluidic Channels

Fornander¹,

Frykholm²,

Fritzsche³

et al. 2016

Langmuir

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RAD51 is the key component of the homologous recombination pathway in eukaryotic cells and performs its task by forming filaments on DNA. In this study we investigate the physical properties of RAD51 filaments formed on DNA using nanofluidic channels and fluorescence microscopy. Contrary to the bacterial ortholog RecA, RAD51 forms inhomogeneous filaments on long DNA in vitro, consisting of several protein patches. We demonstrate that a permanent "kink" in the filament is formed where two patches meet if the stretch of naked DNA between the patches is short. The kinks are readily seen in the present microscopy approach but would be hard to identify using conventional single DNA molecule techniques where the DNA is more stretched. We also demonstrate that protein patches separated by longer stretches of bare DNA roll up on each other and this is visualized as transiently overlapping filaments. RAD51 filaments can be formed at several different conditions, varying the cation (Mg 2+ or Ca 2+ ), the DNA substrate (single-stranded or doublestranded), and the RAD51 concentration during filament nucleation, and we compare the properties of the different filaments formed. The results provide important information regarding the physical properties of RAD51 filaments but also demonstrate that nanofluidic channels are perfectly suited to study protein−DNA complexes.

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Lipid-Based Passivation in Nanofluidics

Cited by 88 publications

References 25 publications

Lipid-nanostructure hybrids and their applications in nanobiotechnology

Lipid-nanostructure hybrids and their applications in nanobiotechnology

Nanoconfined Circular and Linear DNA: Equilibrium Conformations and Unfolding Kinetics

Visualizing the Nonhomogeneous Structure of RAD51 Filaments Using Nanofluidic Channels

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