Adsorption and binding dynamics of graphene-supported phospholipid membranes using the QCM-D technique

We report on the adsorption dynamics of phospholipid membranes on graphene-coated substrates using the quartz crystal microbalance with dissipation monitoring (QCM-D) technique. We compare the lipid vescle interaction and membranne formation on gold and silicon dioxide QCM crystal surfaces with their graphene oxide (GO) and reduced (r)GO coated counterparts, and report on the different lipid structures obtained. We establish graphene derivative coatings as support surfaces with tuneable hydrophobicity for the formation of controllable lipid structures. One structure of interest formed are lipid monolayer membrannes which were formed on rGO, which are otherwise challenging to produce. We also demonstrate and monitor biotin-avidin binding on such a membranne, which will then serve as a platform for a wide range of biosensing applications. The QCM-D technique could be extended to both fundamental studies and applications of other covalent and non-covalent interactions in 2-dimensional materials

Formulation of a multifunctional coating based on polyphenols extracted from the Pine radiata bark and functionalized zinc oxide nanoparticles: Evaluation of hydrophobic and anticorrosive properties

With the purpose of improving the protection of steel ASTM A36 from corrosion, in this paper the use of tannin as an inhibitor was studied by incorporating it in an epoxy resin along with zinc oxide nanoparticles functionalized with 3-aminopropyltriethoxysilane (APTES) in concentrations of 1, 3, and 5w/w. Electrochemical techniques such as polarization curves and EIS for the characterization of the anticorrosive properties, SKP for the study of coating delamination with the substrate, contact angle measurement and other standardized methods were used for the evaluation of the properties of the film. The results of the polarization curves revealed that the corrosion current density of the steel (icorr) decreases markedly with the addition of the tannin extract by changing the cathodic behavior without affecting the active anodic behavior. Likewise, the EIS analysis showed that the coatings with surface modified nanoparticles provide an excellent protection against corrosion that is complemented by the protective layer of the tannin-iron complex formed and the same was confirmed by FTIR spectroscopy after exposing the plates to accelerated corrosion tests in salt spray and weathering chamber. Finally, it could be demonstrated that the incorporation of zinc oxide nanoparticles in the coating formulation subtly improves the film properties and likewise, partially increases the hydrophobicity. © 2019 Elsevier B.V

Comparative Study of the Antimicrobial Effect of Nanocomposites and Composite Based on Poly(butylene adipate-co-terephthalate) Using Cu and Cu/Cu2O Nanoparticles and CuSO4

Abstract Nanocomposites and a composite based on poly(butylene adipate-co-terephthalate) (PBAT) were synthesized using commercial copper nanoparticles (Cu-NPs), copper/cuprous oxide nanoparticles (Cu|Cu2O-NPs), and copper sulfate (CuSO4), respectively. The Cu|Cu2O-NPs were synthesized using chemical reduction and characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The synthesis of Cu|Cu2O-NPs yielded a mixture of Cu and Cu2O, with metal Cu having a spherical morphology of approximately 40 nm in diameter and Cu2O with a diameter of 150 nm. To prepare the nanocomposites (NCs) and the composite material (MC), the NPs and the CuSO4 salt were incorporated into the PBAT matrix in concentrations of 1, 3, and 5% p/p via an ex situ method. Fourier transform infrared spectroscopy (FTIR), a tensile test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and agar diffusion assays were used for structural, thermomechanical, and antimicrobial characterization. Results showed that the reinforcements did not modify the chemical structure of the PBAT and only slightly increased the percentage of crystallization. The mechanical and thermal properties of the PBAT did not change much with the addition of fillers, except for a slight increase in tensile strength and thermal stability, respectively. The agar diffusion antimicrobial assays showed that the NCs and MCs had good inhibitory responses against the nonresistant strains Enterococcus faecalis, Streptococcus mutans, and Staphylococcus aureus. The MCs based on CuSO4 had the highest biocidal effect, even against the resistant bacteria Acinetobacter baumannii