Journal of Nano Research Vol. 20

Abstract: Silver nanoparticles production was monitored by UVVis and TEM micrograph and they were obtained as spherical and homogenous nanoparticles with a size of ~100 nm by photon correlation spectroscopy (PCS). Silver nanoparticles, in an IC₈₀ range of 1-2 μg/mL, showed significant antifungal activity against T. rubrum. Cytotoxicity through hemolytic activity against erythrocytes and the viability of V79 fibroblast or HL60 cells showed less toxicity than amphotericin B. The disk diffusion test showed that the silver nanoparticles exerted a similar inhibition zone that amphotericin B by a synergistic effect when added at the same time against T. rubrum culture.

Abstract: In this paper, we focus on the need for real time nanomanipulation, a 3D Master/Slave tele-nanomanipulation platform is studied with the haptic device (Omega3) as the master and the nanopositioner (Attocube) as the slave, working in scanning electron microscope (SEM). The 3D manipulation environment is developed with the help of VR technology. The platform is controlled by the enhanced virtual coupling (EVC) algorithm. The stability of the platform is discussed with Llewellyns stability criteria. Scale factors and enhancement factor of the control system are determined, according to the force applied on master and slave terminals. Performances of the platform are tested with the ZnO nanowire manipulation experiments. Experiment results show that the platform has good performance while guaranteeing stability on ZnO nanowires manipulation in SEM using the method presented in this paper.

Abstract: This paper presents the practical strategies of obtaining the oriented nanostructured surfaces of some polymers functionalized with monochlorotriazinyl-β-cyclodextrin (MCT-β-CD) by two techniques: uniaxial rubbing or linearly polarized UV light (LPUVL) irradiation. We have chosen for the present study polymers and copolymers with exotic behavior with hydroxyl groups allowing the grafting of the reactive product monochlorotriazinyl-β-cyclodextrin or whose pyridinic nuclei can be complexated with MCT-β-CD. The obtained oriented nanostructures align colourless nematic liquid crystals (NLC) or NLC coloured with a dichroic dye. The orientation of NLC has been studied by means of polarized light FT-IR spectroscopy (IR dichroism) and polarized light UV-VIS spectroscopy (VIS dichroism). The initial polymers as well as the chemically modified products have an exotic behavior with regard to the ability of orientating the NLC. The polymers functionalized with MCT-β-CD orientate the NLC perpendicularly to the rubbing direction (or, for photopolymers, perpendicularly to the electrical vector of LPUVL).

Abstract: The capability to understand and modulate accurately the self-assembly of the extracellular matrix (ECM) components still one of the major fundamental objectives in the field of liver tissue engineering. In the present study, we put in evidence the suitability of poly-chloro-p-xylene (Parylene-C, ParC) for modulating the self-assembly of ECM (type-I collagen) microenvironment and cellular topography of human hepatocarcinoma (HepG2) and Human umbilical vascular endothelial (HUVEC) cells while coated on a polydimethylsiloxane (PDMS) substratum. Our findings demonstrated that the wettability of PDMS and ParC/PDMS were identical, while ParC/PDMS was significantly rougher than PDMS before and after collagen coating. However, the roughness and the wettability of ParC/PDMS were comparable to those of polystyrene (PS), a substratum commonly used for in vitro biological-related investigations. Type-I collagen adsorbed on ParC/PDMS and PS exhibited a dense network of microstructures around ~1 nm high and ~30-50 nm wide, whereas collagen adsorbed on PDMS had a low surface density of elongated fibrils that were ~2 nm thick and ~200 nm wide. This disparity in ECM microarchitecture leaded to distinct culture topographies of HepG2 cells (3D and 2D for PDMS and ParC/PDMS, respectively) and viability of HUVEC (2D viable HUVEC cells and non attached dead cells on ParC/PDMS and PDMS, respectively). To conclude, the observed changes in cell morphology and viability between ParC/PDMS and PDMS alone were directly related to the nature of the material which may impact the supramolecular organization of adsorbed ECM. We strongly believe that Low Pressure Chemical Vapour deposition (LPCVD) of ParC will offer promising insights into how microscale ECM modifications directly impact cell morphology and activity, leading to the development of advanced micro/nanosized tissue-engineered ParC/PDMS patterns with applications for liver tissue engineering.

Abstract: The approach for converting nanoscale mechanical energy into electrical energy using piezoelectric nanowire arrays has been shown by a deflection of the nanowires via a corrugated electrode operated up and down by ultrasounds. I have performed an analytical method for describing the most important quantities concerning transport phenomena; it predicts very high initial diffusion of charge. This behaviour appears via mechanical external device stresses, which assumes therefore the typical characteristics of a nanosensor. With this method it is possible to deduce interesting informations about the device sensitivity, focusing on the important correlation between sensitivity and high initial diffusivity of these materials at nanometric state.