4 research outputs found
Investigation of the electro-spinnability of alginate solutions containing gold precursor HAuCl4
Alginate nanofibers with an average diameter of 75 nm have been prepared by the electrospinning process. In addition, the spinnability of the solutions in the presence of the gold precursor HAuCl4 was investigated. At low concentrations of HAuCl4 well-formed nanofibers were produced, whereas as its concentration increases the nanofibrous mats present an increased number of bead-like defects. Herein, the in situ preparation of gold nanoparticles (Au NPs) is discussed since sodium alginate (SA) acts as the reducing agent and a mechanism is proposed in order to explain the bead-effect as well as the surface morphology of the alginate fibers decorated with Au NPs
Zwitterionic nanofibers of super-glue for transparent and biocompatible multi-purpose coatings
Here we show that macrozwitterions of poly(ethyl 2-cyanoacrylate), commonly called Super Glue, can easily assemble into long and well defined fibers by electrospinning. The resulting fibrous networks are thermally treated on glass in order to create transparent coatings whose superficial
morphology recalls the organization of the initial electrospun mats. These textured coatings are characterized by low liquid adhesion and anti-staining performance. Furthermore, the low friction coefficient and excellent scratch resistance make them attractive as solid lubricants. The inherent
texture of the coatings positively affects their biocompatibility. In fact, they are able to promote the proliferation and differentiation of myoblast stem cells. Optically-transparent and biocompatible
coatings that simultaneously possess characteristics of low water contact angle hysteresis, low friction and mechanical robustness can find application in a wide range of technological sectors, from
the construction and automotive industries to electronic and biomedical devices
Self-Cleaning Organic/Inorganic Photo-Sensors
We present the fabrication of a multifunctional,
hybrid organic–inorganic
micropatterned device, which is capable to act as a stable photosensor
and, at the same time, displaying inherent superhydrophobic self-cleaning
wetting characteristics. In this framework several arrays of epoxy
photoresist square micropillars have been fabricated on n-doped crystalline
silicon substrates and subsequently coated with a polyÂ(3-hexylthiophene-2,5-diyl)
(P3HT) layer, giving rise to an array of organic/inorganic p–n
junctions. Their photoconductivity has been measured under a solar
light simulator at different illumination intensities. The current–voltage
(<i>I</i>–<i>V</i>) curves show high rectifying
characteristics, which are found to be directly correlated with the
illumination intensity. The photoresponse occurs in extremely short
times (within few tens of milliseconds range). The influence of the
interpillar distance on the <i>I</i>–<i>V</i> characteristics of the sensors is also discussed. Moreover, the
static and dynamic wetting properties of these organic/inorganic photosensors
can be easily tuned by changing the pattern geometry. Measured static
water contact angles range from 125° to 164°, as the distance
between the pillars is increased from 14 to 120 ÎĽm while the
contact angle hysteresis decreases from 36° down to 2°
Modified Carbon Nanotubes Favor Fibroblast Growth by Tuning the Cell Membrane Potential
As is known, carbon
nanotubes favor cell growth in vitro, although
the underlying mechanisms are not yet fully elucidated. In this study,
we explore the hypothesis that electrostatic fields generated at the
interface between nonexcitable cells and appropriate scaffold might
favor cell growth by tuning their membrane potential. We focused on
primary human fibroblasts grown on electrospun polymer fibers (poly(lactic
acid)PLA) with embedded multiwall carbon nanotubes (MWCNTs).
The MWCNTs were functionalized with either the p-methoxyphenyl
(PhOME) or the p-acetylphenyl (PhCOMe) moiety, both
of which allowed uniform dispersion in a solvent, good mixing with
PLA and the consequent smooth and homogeneous electrospinning process.
The inclusion of the electrically conductive MWCNTs in the insulating
PLA matrix resulted in differences in the surface potential of the
fibers. Both PLA and PLA/MWCNT fiber samples were found to be biocompatible.
The main features of fibroblasts cultured on different substrates
were characterized by scanning electron microscopy, immunocytochemistry,
Rt-qPCR, and electrophysiology revealing that fibroblasts grown on
PLA/MWCNT reached a healthier state as compared to pure PLA. In particular,
we observed physiological spreading, attachment, and Vmem of fibroblasts on PLA/MWCNT. Interestingly, the electrical
functionalization of the scaffold resulted in a more suitable extracellular
environment for the correct biofunctionality of these nonexcitable
cells. Finally, numerical simulations were also performed in order
to understand the mechanism behind the different cell behavior when
grown either on PLA or PLA/MWCNT samples. The results show a clear
effect on the cell membrane potential, depending on the underlying
substrate