The Effects of Cholesterol Oxidation on Erythrocyte Plasma Membranes: A Monolayer Study.

Cholesterol plays a key role in the molecular and mesoscopic organisation of lipid membranes and it is expected that changes in its molecular structure (e.g., through environmental factors such as oxidative stress) may affect adversely membrane properties and function.

Electric-Field-Driven Translocation of ssDNA through Hydrophobic Nanopores.

The accurate sequencing of DNA using nanopores requires control over the speed of DNA translocation through the pores and also of the DNA conformation. Our studies show that ssDNA translocates through hourglass-shaped pores with hydrophobic constriction regions when an electric field is applied. The constriction provides a barrier to translocation and thereby slows down DNA movement through the pore compared with pores without the constriction.

Glycerol Solvates DPPC Headgroups and Localizes in the Interfacial Regions of Model Pulmonary Interfaces Altering Bilayer Structure.

The inclusion of glycerol in formulations for pulmonary drug delivery may affect the bioavailability of inhaled steroids by retarding their transport across the lung epithelium. The aim of this study was to evaluate whether the molecular interactions of glycerol with model pulmonary interfaces provide a biophysical basis for glycerol modifying inhaled drug transport. Dipalmitoylphosphatidylcholine (DPPC) monolayers and liposomes were used as model pulmonary interfaces, in order to examine the effects of bulk glycerol (0-30% w/w) on their structures and dynamics using complementary biophysical measurements and molecular dynamics (MD) simulations.

Voltage Gating of a Biomimetic Nanopore: Electrowetting of a Hydrophobic Barrier.

It is desirable that nanopores that are components of biosensors are gated, i.e., capable of controllable switching between closed (impermeable) and open (permeable) states.

Functional Annotation of Ion Channel Structures by Molecular Simulation.

Ion channels play key roles in cell membranes, and recent advances are yielding an increasing number of structures. However, their functional relevance is often unclear and better tools are required for their functional annotation. In sub-nanometer pores such as ion channels, hydrophobic gating has been shown to promote dewetting to produce a functionally closed (i.

Lipid Bilayer Membrane Perturbation by Embedded Nanopores: A Simulation Study.

A macromolecular nanopore inserted into a membrane may perturb the dynamic organization of the surrounding lipid bilayer. To better understand the nature of such perturbations, we have undertaken a systematic molecular dynamics simulation study of lipid bilayer structure and dynamics around three different classes of nanopore: a carbon nanotube, three related cyclic peptide nanotubes differing in the nature of their external surfaces, and a model of a β-barrel nanopore protein. Periodic spatial distributions of several lipid properties as a function of distance from the nanopore were observed.

Molecular simulation studies of hydrophobic gating in nanopores and ion channels.

Gating in channels and nanopores plays a key role in regulating flow of ions across membranes. Molecular simulations provide a 'computational microscope' which enables us to examine the physical nature of gating mechanisms at the level of the single channel molecule. Water enclosed within the confines of a nanoscale pore may exhibit unexpected behaviour.

Designing a hydrophobic barrier within biomimetic nanopores.

Nanopores in membranes have a range of potential applications. Biomimetic design of nanopores aims to mimic key functions of biological pores within a stable template structure. Molecular dynamics simulations have been used to test whether a simple β-barrel protein nanopore can be modified to incorporate a hydrophobic barrier to permeation.