Functionalization of Titanium surface with Chitosan via silanation: 3D CLSM imaging of cell biocompatibility behaviour

Introduction Biocompatibility ranks as one of the most important properties of dental materials. One of the criteria for biocompatibility is the absence of material toxicity to cells, according to the ISO 7405 and 10993 recommendations. Among numerous available methods for toxicity assessment; 3-dimensional Confocal Laser Scanning Microscopy (3D CLSM) imaging was chosen because it provides an accurate and sensitive index of living cell behavior in contact with chitosan coated tested implants. Objectives: The purpose of this study was to investigate the in vitro biocompatibility of functionalized titanium with chitosan via a silanation using sensitive and innovative 3D CLSM imaging as an investigation method for cytotoxicity assessment. Methods The biocompatibility of four samples (controls cells, TA6V, TA6V-TESBA and TA6V-TESBAChitosan) was compared in vitro after 24h of exposure. Confocal imaging was performed on cultured human gingival fibroblast (HGF1) like cells using Live/Dead® staining. Image series were obtained with a FV10i confocal biological inverted system and analyzed with FV10-ASW 3.1 Software (Olympus France). Results Image analysis showed no cytotoxicity in the presence of the three tested substrates after 24 h of contact. A slight decrease of cell viability was found in contact with TA6V-TESBA with and without chitosan compared to negative control cells. Conclusion Our findings highlighted the use of 3D CLSM confocal imaging as a sensitive method to evaluate qualitatively and quantitatively the biocompatibility behavior of functionalized titanium with chitosan via a silanation. The biocompatibility of the new functionalized coating to HGF1 cells is as good as the reference in biomedical device implantation TA6V

Direct observation and control of near-field radiative energy transfer in a natural hyperbolic material

Heat control is a key issue in nano-electronics, where new efficient energy transfer mechanisms are highly sought after. In this respect, there is indirect evidence that high-mobility hexagonal boron nitride (hBN)-encapsulated graphene exhibits hyperbolic out-of-plane radiative energy transfer when driven out-of-equilibrium. Here we directly observe radiative energy transfer due to the hyperbolic phonon polaritons modes of the hBN encapsulant in intrinsic graphene devices under large bias, using mid-infrared spectroscopy and pyrometry. By using different hBN crystals of varied crystalline quality, we engineer the energy transfer efficiency, a key asset for compact thermal management of electronic circuits.Comment: 21 pages including Supplementary Material (Main text: 10 pages, 4 figures

Primary rat sertoli and interstitial cells exhibit a differential response to cadmium

Two cell types central to the support of spermatogenesis, the Sertoli cell and the interstitial (Leydig) cell, were isolated from the same cohort of young male rats and challenged with cadmium chloride to compare their susceptibility to the metal. Both cell types were cultured under similar conditions, and similar biochemical endpoints were chosen to minimize experimental variability. These endpoints include the uptake of 109 Cd, reduction of the vital tetrazolium dye MTT, incorporation of 3 H-leucine, change in heat-stable cadmium binding capacity, and production of lactate. Using these parameters, it was observed that the Sertoli cell cultures were adversely affected in a dose-and time-dependent manner, while the interstitial cell cultures, treated with identical concentrations of CdCl 2 , were less affected. The 72-hr LC 50 's for Sertoli cells and interstitial cells were 4.1 and 19.6 μM CdCl 2 , respectively. Thus, different cell populations within the same tissue may differ markedly in susceptibility to a toxicant. These in vitro data suggest that the Sertoli cell, in relation to the interstitium, is particularly sensitive to cadmium. Because the Sertoli cell provides functional support for the seminiferous epithelium, the differential sensitivity of this cell type may, in part, explain cadmium-induced testicular dysfunction, particularly at doses that leave the vascular epithelium intact.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42554/1/10565_2004_Article_BF00135027.pd

Synthesis of hexagonal boron nitride graphene-like few layers

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Two-liquid wetting properties as a surface polarity probe for hydrophobic coatings

International audienceA model for the spreading of a non-polar liquid on a surface within a polar medium is described theoretically, according to Fowkes, Good and Girifalco approximations on interfacial tension. We demonstrate both theoretically and experimentally that surface polarity measurements using the contact angle of two immiscible liquids minimize drastically the measurement error. The present method has been successfully applied to various substrates of variable polarity and overall surface energy. We also demonstrate that this method allows a direct measurement of surface sensitivity to pH

THERMAL OLIGOMERIZATION OF UNSYMMETRICALLY B-TRISUBSTITUTED BORAZINES

International audienceThe B-alkylaminosubstituted borazines (NEt 2) 3 B 3 N 3 H 3 (1), (ΝΕ1 2) 2 (ΝΗΡ0Β 3 Ν 3 Η 3 (2), (NEt 2)(NHPr') 2 B 3 N 3 H 3 (3) and (NMe 2)(NHMe) 2 B 3 N 3 l-l3 (4) have been prepared and characterized by spectroscopic techniques. Their thermolyses at moderate temperature have been investigated in order to elucidate the effects of the nature of the B-alkylamino substituents on the resulting polyborazines backbone. Early stages of the degradations were accompanied by the elimination of primary and secondary amines for (2), (3) and (4). On the basis of 13 C NMR data, oligomerizations have been shown to occur mainly via the formation of direct interring B-N bonds rather than classical deamination with formation of-N(R)-bridges between borazine rings. This phenomenon should be related to the presence of dialkylamino substituents on the boron atoms

Preparation of ZnO nanoparticles localized on SiC@SiO2 nanocables by a physical templating method

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