Sol-gel 3-glycidoxypropyltriethoxysilane finishing on different fabrics: The role of precursor concentration and catalyst on the textile performances and cytotoxic activity.

In this paper, the influence of 3-glycidoxypropyltriethoxysilane (GPTES) based organic-inorganic coatings on the properties of treated textile fabrics was studied. All experimental results were deeply analyzed and thereafter correlated with the employed silica precursor concentration and with the presence of the BF3OEt2 (Boron trifluoride diethyl etherate), used as epoxy ring opening catalyst. SEM analysis, FT-IR spectroscopy, X-ray Photoelectron Spectroscopy (XPS), thermogravimetric analysis (TGA) and washing fastness tests of the sol-gel treated cotton fabric samples were firstly exploited in order to characterize the morphological and structural features of the achieved coatings. Finally, the influence of the resulting nanohybrid coatings was explored in terms of abrasion resistance, tensile strength and elongation properties of treated cotton, polyester and silk fabrics. The catalyst amounts seem to strongly improve the formation of coatings, but still they do not influence the wear resistance of treated textile fabrics to the same extent. Indeed, it was found that increasing catalyst/GPTES ratio leads to a more cross linked inorganic 3D-network. GPTES itself was not found to affect the bulk properties of the selected textile and the resulting coatings were not so rigid to hardly modify the mechanical properties of the treated samples. Finally, it is worth mentioning that in all case the obtained 3-glycidoxypropyltriethoxysilane-based chemical finishing have shown no cytotoxic effects on human skin cells.

Thermoelectric Analysis of ZnSb Thin Films Prepared by ns-Pulsed Laser Deposition.

Zinc antimonide (ZnSb) is a promising thermoelectric material for the temperature range 300­ 600 K. ZnSb thin films were prepared by nanosecond Pulsed Laser Deposition (PLD) to evaluate the performance of nanostructured films for thermoelectric conversion by the determination of the Power Factor. A study of the influence of structural, compositional and thermoelectric properties of thin films is reported as a function of different deposition parameters, such as repetition rate, pulse energy, and substrate temperature. The evaluation of a thin film ZnSb compound with excess Sb has been performed to verify the variation of the thermoelectric properties. The obtained results are reported and discussed in the 300­600 K temperature range.

Magnetic hydroxyapatite coatings as a new tool in medicine: A scanning probe investigation.

Hydroxyapatite films enriched with magnetite have been fabricated via a Pulsed Plasma Deposition (PPD) system with the final aim of representing a new platform able to disincentivate bacterial adhesion and biofilm formation. The chemical composition and magnetic properties of films were respectively examined by X-ray photoelectron spectroscopy (XPS) and Superconducting Quantum Interference Device (SQUID) measurements. The morphology and conductive properties of the magnetic films were investigated via a combination of scanning probe technologies including atomic force microscopy (AFM), electrostatic force microscopy (EFM), and scanning tunneling microscopy (STM). Interestingly, the range of adopted techniques allowed determining the preservation of the chemical composition and magnetic properties of the deposition target material while STM analysis provided new insights on the presence of surface inhomogeneities, revealing the presence of magnetite-rich islands over length scales compatible with the applications. Finally, preliminary results of bacterial adhesion tests, indicated a higher ability of magnetic hydroxyapatite films to reduce Escherichia coli adhesion at 4h from seeding compared to control hydroxyapatite films.

Cell mechanotactic and cytotoxic response to zinc oxide nanorods depends on substrate stiffness.

Bio-nanomaterials offer promise in the field of tissue engineering. Specifically, environmental cues such as the material chemistry, topography and rigidity of the surface to which cells adhere to, can alter and dictate cell shape, proliferation, migration, and gene expression. How deeply each factor (topographical, chemical and mechanical) drives cell response remains incompletely understood. To illustrate cell sensitivities to different factors, we herein present ZnO nanorods (ZnO-Nrds) coated on glass and polydimethylsiloxane (PDMS) substrates and analyzed cell viability and proliferation. The work presented here shows a clear response of various cell lines (mouse embryonic fibroblasts 3T3, human cervix carcinoma HeLa and human osteoblast-like cells MG63) to the rigidity of the underlying surface. The chemical counterpart, given by the presence of ZnO-Nrds, strongly reduced the cell viability of all cell lines. However, the substrate underlying the ZnO coating impacted cell spreading and viability. The substrates exhibited a better ability to neglect cell attachment and proliferation with the ZnO coating and pro-apoptoticity specifically with the PDMS as the underlying substrate which exhibited a "softer" environment with respect to a glass substrate. The results also revealed that the few cells that adhered to the ZnO-Nrds on PDMS and glass showed a rounded morphology. On the basis of these observations, we can correlate common features of phenomenological cell response to chemotactic and durotactic cues. The work presented herein reinforces the response of cells to changes in substrate rigidity. These observations provide a foundation for a potentially promising approach to decrease cell adhesion and thus as an optimal substrate for different applications such as prosthesis design, tissue engineering, anti-bio fouling materials and diagnostics.