Graphene-like BN/gelatin nanobiocomposites for gas barrier applications.

We report a simple, effective and green way for the fabrication of gelatin-graphene-like BN nanocomposites for gas barrier applications. The reinforcement effect of graphene-like BN on the gelatin properties is discussed. The obtained graphene-like BN nanocomposites show good dispersion in the gelatin matrix and remarkable capability to improve the crystallinity and the barrier properties of gelatin. The barrier properties of gelatin/BN nanocomposites have been enhanced by a factor of 500 at 2 bar compared to a gelatin film without graphene-like BN. The greatly improved performance and the high stability of these nanocomposites may lead exciting materials for their implantation in gas barrier applications.

Experimental and simulation studies of unusual current blockade induced by translocation of small oxidized PEG through a single nanopore.

Detection of a single macromolecule based on the use of artificial nanopores is an attractive and promising field of research. In this work, we report a device based on a 5 nm single nanopore with a high length/diameter ratio, tailored by the track etching and atomic layer deposition techniques. The translocation of neutral polyethylene glycol (PEG) and charged polyethylene glycol-carboxylate (PEG-carboxylate) molecules of low molar masses (200 and 600 g mol(-1)) through this nanodevice was studied. It was shown that charged PEG-carboxylate molecules, which permeate through the pore, promote an unusual blockade of ionic current whereas the neutral PEG molecules do not show such behaviour. The molecular dynamics simulation shows that both neutral and charged PEGs permeate through the nanopore close to its inner surface. The main difference between the two macromolecules is the existence of a structured shell of cations around the charged PEG, which is likely to cause the observed unusual current blockade.

Preparation and characterization of chitin hydrogels by water vapor induced gelation route.

A novel method of chitin hydrogel preparation, called vapor induced gelation, using exposure of chitin/N-methyl-pyrrolidone/LiCl solution to water vapors is presented. Compared to gelation induced by direct immersion in water, hydrogels are characterized by smaller deformation during gelation (area shrinkage is 20% instead of 65%), larger water volume fraction (75 instead of 62%, v/v) and 10 times higher apparent compression moduli. Their nanostructure consists of thicker and larger crystalline platelets network (thickness=37 Å, apparent coherent crystalline size L020=145 Å) comparatively to direct immersion gels (25 Å and L020=95 Å). Drug delivery potential of chitin hydrogels was determined for non-interactive low molecular molecules.