scholarly journals General and robust covalently linked graphene oxide affinity grids for high-resolution cryo-EM

2019 ◽  
Author(s):  
Feng Wang ◽  
Yanxin Liu ◽  
Zanlin Yu ◽  
Sam Li ◽  
Yifan Cheng ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Polyethylene Glycol ◽  
High Resolution ◽  
Oxide Surface ◽  
Water Interface ◽  
Small Particles ◽  
Affinity Tag ◽  
Rapid Preparation ◽  
Air Water Interface ◽  
Covalently Linked

AbstractDespite their great potential to facilitate rapid preparation of quite impure samples, affinity grids have not yet been widely employed in single particle cryo-EM. Here, we chemically functionalize graphene oxide coated grids and use a highly specific covalent affinity tag system. Importantly, our polyethylene glycol spacer keeps particles away from the air-water interface and graphene oxide surface, protecting them from denaturation or aggregation and permits high-resolution reconstructions of small particles.

scholarly journals General and robust covalently linked graphene oxide affinity grids for high-resolution cryo-EM

2020 ◽  
Vol 117 (39) ◽  
pp. 24269-24273 ◽  
Author(s):  
Feng Wang ◽  
Yanxin Liu ◽  
Zanlin Yu ◽  
Sam Li ◽  
Shengjie Feng ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
High Resolution ◽  
Covalent Bond ◽  
Oxide Surface ◽  
Rapid Preparation ◽  
Affinity Capture ◽  
General Utility ◽  
Sample Orientation ◽  
Single Strategy ◽  
Covalently Linked

Affinity grids have great potential to facilitate rapid preparation of even quite impure samples in single-particle cryo-electron microscopy (EM). Yet despite the promising advances of affinity grids over the past decades, no single strategy has demonstrated general utility. Here we chemically functionalize cryo-EM grids coated with mostly one or two layers of graphene oxide to facilitate affinity capture. The protein of interest is tagged using a system that rapidly forms a highly specific covalent bond to its cognate catcher linked to the grid via a polyethylene glycol (PEG) spacer. Importantly, the spacer keeps particles away from both the air–water interface and the graphene oxide surface, protecting them from potential denaturation and rendering them sufficiently flexible to avoid preferential sample orientation concerns. Furthermore, the PEG spacer successfully reduces nonspecific binding, enabling high-resolution reconstructions from a much cruder lysate sample.

scholarly journals Amino and PEG-Amino Graphene Oxide Grids Enrich and Protect Samples for High-resolution Single Particle Cryo-electron Microscopy

2019 ◽  
Author(s):  
Feng Wang ◽  
Zanlin Yu ◽  
Miguel Betegon ◽  
Melody Campbell ◽  
Tural Aksel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Graphene Oxide ◽  
High Resolution ◽  
Single Particle ◽  
Particle Distribution ◽  
Water Interface ◽  
Amino Groups ◽  
Cryo Electron Microscopy ◽  
Air Water Interface ◽  
Resolution Single

AbstractCryo-EM samples prepared using the traditional methods often suffer from too few particles, poor particle distribution, or strongly biased orientation, or damage from the air-water interface. Here we report that functionalization of graphene oxide (GO) coated grids with amino groups concentrates samples on the grid with improved distribution and orientation. By introducing a PEG spacer, particles are kept away from both the GO surface and the air-water interface, protecting them from potential denaturation.

Dispersion of Particles on Liquid Surfaces

2011 ◽  
Author(s):  
Shriram B. Pillapakkam ◽  
Pushpendra Singh
Keyword(s):  
Numerical Simulation ◽  
Particle Size ◽  
Vertical Motion ◽  
Liquid Interface ◽  
Water Interface ◽  
Small Particles ◽  
Air Water Interface ◽  
Large Velocity ◽  
Simulation Results ◽  
Air Liquid Interface

In a recent study we have shown that when small particles, e.g., flour, pollen, glass, etc., contact an air-liquid interface, they disperse rapidly as if they were in an explosion. The rapid dispersion is due to the fact that the capillary force pulls particles into the interface causing them to accelerate to a large velocity. The vertical motion of a particle during its adsorption causes a radially-outward lateral (secondary) flow on the interface that causes nearby particles to move away. We present direct numerical simulation results for the adsorption of particles and show that the inertia of a particle plays an important role in its motion in the direction normal to a fluid-liquid interface. Although the importance of inertia diminishes with decreasing particle size, on an air-water interface the inertia continues to be important even when the size is as small as a few nanometers.

Fabrication of morphology controlled graphene oxide-dye composite films at the air–water interface

RSC Advances ◽  
2015 ◽  
Vol 5 (1) ◽  
pp. 552-557 ◽  
Author(s):  
Bahri Gür ◽  
Mehmet Şinoforoğlu ◽  
Kadem Meral
Keyword(s):  
Graphene Oxide ◽  
Composite Films ◽  
Water Interface ◽  
Two Dimensional ◽  
Langmuir Blodgett ◽  
Air Water Interface ◽  
Facile Route

This study presents a facile route for preparing two-dimensional (2D) graphene oxide-based composite films using the Langmuir–Blodgett (LB) method.

scholarly journals Reduced graphene oxide membrane as supporting film for high-resolution cryo-EM

2021 ◽  
Author(s):  
Nan Liu ◽  
Liming Zheng ◽  
Jie Xu ◽  
Jia Wang ◽  
Cuixia Hu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
High Resolution ◽  
Reduced Graphene Oxide ◽  
Interface Problem ◽  
Specimen Preparation ◽  
Simple Method ◽  
Reduced Graphene ◽  
Two Dimensional Materials ◽  
Air Water Interface ◽  
Oxide Membrane

AbstractAlthough single-particle cryogenic electron microscopy (cryo-EM) has been applied extensively for elucidating many crucial biological mechanisms at the molecular level, this technique still faces critical challenges, the major one of which is to prepare the high-quality cryo-EM specimen. Aiming to achieve a more reproducible and efficient cryo-EM specimen preparation, novel supporting films including graphene-based two-dimensional materials have been explored in recent years. Here we report a robust and simple method to fabricate EM grids coated with single- or few-layer reduced graphene oxide (RGO) membrane in large batch for high-resolution cryo-EM structural determination. The RGO membrane has decreased interlayer space and enhanced electrical conductivity in comparison to regular graphene oxide (GO) membrane. Moreover, we found that the RGO supporting film exhibited nice particle-absorption ability, thus avoiding the air-water interface problem. More importantly, we found that the RGO supporting film is particularly useful in cryo-EM reconstruction of sub-100 kDa biomolecules at near-atomic resolution, as exemplified by the study of RBD-ACE2 complex and other small protein molecules. We envision that the RGO membranes can be used as a robust graphene-based supporting film in cryo-EM specimen preparation.

scholarly journals Competitive and/or cooperative interactions of graphene-family materials and benzo[a]pyrene with pulmonary surfactant: a computational and experimental study

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Tongtao Yue ◽  
Rujie Lv ◽  
Dongfang Xu ◽  
Yan Xu ◽  
Lu Liu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Pulmonary Surfactant ◽  
The Body ◽  
Water Interface ◽  
Alveolar Air ◽  
Interfacial Processes ◽  
Air Water Interface ◽  
Graphene Oxidation ◽  
Inhaled Nanoparticles ◽  
Graphene Family Materials

Abstract Background Airborne nanoparticles can be inhaled and deposit in human alveoli, where pulmonary surfactant (PS) molecules lining at the alveolar air–water interface act as the first barrier against inhaled nanoparticles entering the body. Although considerable efforts have been devoted to elucidate the mechanisms underlying nanoparticle-PS interactions, our understanding on this important issue is limited due to the high complexity of the atmosphere, in which nanoparticles are believed to experience transformations that remarkably change the nanoparticles’ surface properties and states. By contrast with bare nanoparticles that have been extensively studied, relatively little is known about the interactions between PS and inhaled nanoparticles which already adsorb contaminants. In this combined experimental and computational effort, we investigate the joint interactions between PS and graphene-family materials (GFMs) with coexisting benzo[a]pyrene (BaP). Results Depending on the BaP concentration, molecular agglomeration, and graphene oxidation, different nanocomposite structures are formed via BaPs adsorption on GFMs. Upon deposition of GFMs carrying BaPs at the pulmonary surfactant (PS) layer, competition and cooperation of interactions between different components determines the interfacial processes including BaP solubilization, GFM translocation and PS perturbation. Importantly, BaPs adsorbed on GFMs are solubilized to increase BaP’s bioavailability. By contrast with graphene adhering on the PS layer to release part of adsorbed BaPs, more BaPs are released from graphene oxide, which induces a hydrophilic pore in the PS layer and shows adverse effect on the PS biophysical function. Translocation of graphene across the PS layer is facilitated by BaP adsorption through segregating it from contact with PS, while translocation of graphene oxide is suppressed by BaP adsorption due to the increase of surface hydrophobicity. Graphene extracts PS molecules from the layer, and the resultant PS depletion declines with graphene oxidation and BaP adsorption. Conclusion GFMs showed high adsorption capacity towards BaPs to form nanocomposites. Upon deposition of GFMs carrying BaPs at the alveolar air–water interface covered by a thin PS layer, the interactions of GFM-PS, GFM-BaP and BaP-PS determined the interfacial processes of BaP solubilization, GFM translocation and PS perturbation.

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