Stability of Nanopeptides: Structure and Molecular Exchange of Self-assembled Peptide Fibers.

Often nanostructures formed by self-assembly of small molecules based on hydrophobic interactions are rather unstable, causing morphological changes or even dissolution when exposed to changes in aqueous media. In contrast, peptides offer precise control of the nanostructure through a range of molecular interactions where physical stability can be engineered in and, to a certain extent, decoupled from size via rational design. Here, we investigate a family of peptides that form beta-sheet nanofibers and demonstrate a remarkable physical stability even after attachment of poly(ethylene glycol).

Herpes simplex virus alters Alzheimer's disease biomarkers - A hypothesis paper.

Introduction: Human herpes simplex virus 1 (HSV1) is discussed to induce amyloid-β (Aβ) accumulation and neurofibrillary tangles of hyperphosphorylated tau (pTau) in Alzheimer's disease (AD) in cell culture and animal models. Aβ appears to be virostatic. We investigated the association between intrathecal antibodies against HSV or cytomegalovirus (CMV) and cerebrospinal fluid (CSF) AD biomarkers.

Cooperative Chain Dynamics of Tracer Chains in Highly Entangled Polyethylene Melts.

By neutron spin echo spectroscopy, we have studied the center of mass motion of short tracer chains on the molecular length scale within a highly entangled polymer matrix. The center of mass mean square displacements of the tracers independent of their molecular weight is subdiffusive at short times until it has reached the size of the tube d; then, a crossover to Fickian diffusion takes place. This observation cannot be understood within the tube model of reptation, but is rationalized as a result of important interchain couplings that lead to cooperative chain motion within the entanglement volume ∼d^{3}.

Manipulating Phospholipid Vesicles at the Nanoscale: A Transformation from Unilamellar to Multilamellar by an -Alkyl-poly(ethylene oxide).

We investigated the influence of an -alkyl-PEO polymer on the structure and dynamics of phospholipid vesicles. Multilayer formation and about a 9% increase in the size in vesicles were observed by cryogenic transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS), and small-angle neutron/X-ray scattering (SANS/SAXS). The results indicate a change in the lamellar structure of the vesicles by a partial disruption caused by polymer chains, which seems to correlate with about a 30% reduction in bending rigidity per unit bilayer, as revealed by neutron spin echo (NSE) spectroscopy.

Spherical Micelles with Nonspherical Cores: Effect of Chain Packing on the Micellar Shape.

Self-assembly of amphiphilic polymers into micelles is an archetypical example of a "self-confined" system due to the formation of micellar cores with dimensions of a few nanometers. In this work, we investigate the chain packing and resulting shape of C -PEO micelles with semicrystalline cores using small/wide-angle X-ray scattering (SAXS/WAXS), contrast-variation small-angle neutron scattering (SANS), and nuclear magnetic resonance spectroscopy (NMR). Interestingly, the -alkyl chains adopt a rotator-like conformation and pack into prolate ellipses (axial ratio ϵ ≈ 0.