Functional polyaniline nanofibre mats for human adipose-derived stem cell proliferation and adhesion

Conductive polymer poly(aniline-co-m-aminobenzoic acid) (P(ANI-co-m-ABA)) and polyaniline (PANI) were blended with a biodegradable, biocompatible polymer, poly(l-lactic acid) and were electrospun into nanofibres to investigate their potential application as a scaffold for human adipose-derived stem cells (hASCs). These polymers, in both conductive and non-conductive form, were electrospun with average fibre diameters of less than 400 nm. Novel nanoindentation results obtained on the individual nanofibres revealed that the elastic moduli of the nanofibres are much higher at the surface (4–10 GPa, hmax 75 nm). The composite nanofibres showed great promise as a scaffold for hASCs as they supported the cell adhesion and proliferation. After 1 week of cell culture hASCs were well spread on the substrates with abundant focal adhesions. The electrospun mats provide the cells with comparably stiff, sub-micron sized fibres as anchoring points on a substrate of high porosity. The conductive nature of these composite nanofibres offers exciting opportunities for electrical stimulation of the cells

Editorial: Materials for mechanotransduction and beyond

No abstract available

Formation of supramolecular protein structures on gold surfaces

Recent research has highlighted the exciting possibilities enabled by the use of protein structures as nanocomponents to form functional nanodevices. To this end, control over protein–protein and protein–surface interactions is essential. In this study, the authors probe the interaction of human peroxiredoxin 3 with gold surfaces, a protein that has been previously identified as having potential use in nanotechnology. Analytical ultracentrifugation and transmission electron microscopy revealed the pH mediated assembly of protein toroids into tubular structures across a small pH range. Quartz crystal microbalance with dissipation measurements showed differences in absorbed protein mass when pH is switched from pH 8.0 to 7.2, in line with the formation of supramolecular structures observed in solution studies. Scanning tunneling microscopy under ambient conditions showed that these protein tubes form on surfaces in a concentration dependent manner, with a tendency for protein adsorption and supramolecular assembly at the edges of Au(111) terraces. Finally, self-assembled monolayer modification of Au surfaces was explored as a means to control the adsorption and orientation of pH triggered protein structures

Amyloid Fibrils from Hemoglobin

Amyloid fibrils are a class of insoluble protein nanofibers that are formed via the self-assembly of a wide range of peptides and proteins. They are increasingly exploited for a broad range of applications in bionanotechnology, such as biosensing and drug delivery, as nanowires, hydrogels, and thin films. Amyloid fibrils have been prepared from many proteins, but there has been no definitive characterization of amyloid fibrils from hemoglobin to date. Here, nanofiber formation was carried out under denaturing conditions using solutions of apo-hemoglobin extracted from bovine waste blood. A characteristic amyloid fibril morphology was confirmed by transmission electron microscopy (TEM) and atomic force microscopy (AFM), with mean fibril dimensions of approximately 5 nm diameter and up to several microns in length. The thioflavin T assay confirmed the presence of β-sheet structures in apo-hemoglobin fibrils, and X-ray fiber diffraction showed the characteristic amyloid cross-β quaternary structure. Apo-hemoglobin nanofibers demonstrated high stability over a range of temperatures (−20 to 80 °C) and pHs (2–10), and were stable in the presence of organic solvents and trypsin, confirming their potential as nanomaterials with versatile applications. This study conclusively demonstrates the formation of amyloid fibrils from hemoglobin for the first time, and also introduces a cost-effective method for amyloid fibril manufacture using meat industry by-products

Highly processable, rubbery poly(n-butyl acrylate) grafted poly(phenylene vinylene)s

In this study, we have demonstrated a suitable methodology towards tailoring the optical and physical properties of poly(phenylene vinylene)s (PPVs) by grafting poly(n-butyl acrylate) side chains to yield highly processable PPVs with the physical characteristics of the grafted polymer. Grafting from the PPV macroinitiators was conducted using activators regenerated by electron transfer (ARGET) atom transfer radical polymerisation (ATRP) technique. The resulting graft copolymers showed significant enhancement of photoluminescence quantum yield in both solution and in the solid state while exhibiting lower glass transition temperature and dry adhesive properties compared to the ungrafted PPVs, thereby signifying the methodology as an attractive tool for fabricating functional conjugated polymers with desired physical characteristics. (C) 2016 Elsevier Ltd. All rights reserved