skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Nanoscopic lipid domains determined by microscopy and neutron scattering
Biological membranes are highly complex supramolecular assemblies, which play central roles in biology. However, their complexity makes them challenging to study their nanoscale structures. To overcome this challenge, model membranes assembled using reduced sets of membrane-associated biomolecules have been found to be both excellent and tractable proxies for biological membranes. Due to their relative simplicity, they have been studied using a range of biophysical characterization techniques. In this review article, we will briefly detail the use of fluorescence and electron microscopies, and X-ray and neutron scattering techniques used over the past few decades to study the nanostructure of biological membranes.  more » « less
Award ID(s):
2219289
PAR ID:
10526465
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
osti.gov
Date Published:
Journal Name:
Methods
Volume:
223
Issue:
C
ISSN:
1046-2023
Page Range / eLocation ID:
127 to 135
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; (, Symmetry)
    null (Ed.)
    It is well known that the lipid distribution in the bilayer leaflets of mammalian plasma membranes (PMs) is not symmetric. Despite this, model membrane studies have largely relied on chemically symmetric model membranes for the study of lipid–lipid and lipid–protein interactions. This is primarily due to the difficulty in preparing stable, asymmetric model membranes that are amenable to biophysical studies. However, in the last 20 years, efforts have been made in producing more biologically faithful model membranes. Here, we review several recently developed experimental and computational techniques for the robust generation of asymmetric model membranes and highlight a new and particularly promising technique to study membrane asymmetry. 
    more » « less
  2. ; ; ; (, Colloids and Surfaces A: Physicochemical and Engineering Aspects)
    Graphene oxide (GO) membranes, known for their high dielectric constant and low dielectric loss, have emerged as promising separators for advanced energy storage and transfer devices. While previous research has focused on the aqueous stability enhancement by high-valence metal cations, their effect on modifying the dielectric properties of GO membranes remains understudied. This study investigates the impact of transition metal cation modification on the aqueous stability and dielectric properties of graphene oxide (GO) membranes. Multivalent transition metal chlorides (FeCl3, FeCl2, CuCl2, and CuCl) were introduced during the self-assembly process to create modified GO membranes. The membranes were characterized using various techniques, including zeta potential measurements, contact angle measurements, FTIR spectroscopy, and XRD spectroscopy. The aqueous stability of the modified membranes was evaluated, and their dielectric performance was assessed using capacitance measurements across a frequency range of 0.1 Hz to 105 Hz. The results demonstrate that the choice of transition metal cation and its oxidation state significantly influence the morphology, aqueous stability, and dielectric properties of the GO membranes. Notably, Fe3+ and Cu2+ modifications enhanced aqueous stability, while Fe2+ and Cu+ modifications improved dielectric performance. This study provides insights into tailoring the properties of GO membranes for various applications, including energy storage and transfer devices. 
    more » « less
  3. ; ; ; (, Annual Review of Materials Research)
    Aquaporins (AQPs) are naturally occurring water channel proteins. They can facilitate water molecule translocation across cellular membranes with exceptional selectivity and high permeability that are unmatched in synthetic membrane systems. These unique properties of AQPs have led to their use as functional elements in membranes in recent years. However, the intricate nature of AQPs and concerns regarding their stability and processability have encouraged researchers to develop synthetic channels that mimic the structure and properties of AQPs and other biological water-conducting channels. These channels have been termed artificial water channels. This article reviews current progress and provides a historical perspective as well as an outlook toward developing scalable membranes based on artificial water channels. 
    more » « less
  4. ; ; ; ; ; ; ; ; ; (, ChemRxiv)
    Electron imaging of biological samples stained with heavy metals has enabled visualization of nanoscale subcellular structures critical in chemical-, structural-, and neuro-biology. In particular, osmium tetroxide has been widely adopted for selective lipid imaging. Despite the ubiquity of its use, the osmium speciation in lipid membranes and the mechanism for image contrast in electron microscopy (EM) have continued to be open questions, limiting efforts to improve staining protocols and improve high-resolution imaging of biological samples. Following our recent success using photoemission electron microscopy (PEEM) to image mouse brain tissues with a subcellular resolution of 15 nm, we have used PEEM to determine the chemical contrast mechanism of Os staining in lipid membranes. Os (IV), in the form of OsO2, generates aggregates in lipid membranes, leading to a strong spatial variation in the electronic structure and electron density of states. OsO2 has a metallic electronic structure that drastically increases the electron density of states near the Fermi level. Depositing metallic OsO2 in lipid membranes allows for strongly enhanced EM signals of biological materials. This understanding of the membrane contrast mechanism of Os-stained biological specimens provides a new opportunity for the exploration and development of staining protocols for high-resolution, high-contrast EM imaging. 
    more » « less
  5. ; ; ; (, Advanced Materials Technologies)
    Abstract Water pollution is a major global challenge, as conventional polymeric membranes are not adequate for water treatment anymore. Among emerging materials for water treatment, composite membranes are promising, as they have simultaneously improved water permeation and ions rejection. Recently, a new family of 2D materials called MXenes has attracted considerable attention due to their appealing properties and wide applications. MXenes can be incorporated into many polymeric materials due to their high compatibility. MXenes/polymer composite membranes have been found to have appealing electrical, thermal, mechanical, and transport properties, because of strong interactions between polymer chains and surface functional groups of MXenes and the selective nanochannels that are created. This article reviews advances made in the area of ion‐selective MXene‐based membranes for water purification. It puts the advances into perspective and provides prospects. MXenes’ properties and synthesis methods are briefly described. Strategies for the preparation of MXene‐based membranes including mixed‐matrix membranes, thin‐film nanocomposite membranes, and laminated membranes are reviewed. Recent advances in ion‐separation and water‐desalination MXene‐based membranes are elucidated. The dependence of ion‐separation performance of the membranes on fabrication techniques, MXene's interlayer spacing, and MXene's various surface terminations are elucidated. Finally, opportunities and challenges in ion‐selective MXene‐based membranes are discussed. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email