In vitro biocompatibility of a dentine substitute cement on human MG63 osteoblasts cells: Biodentine™ versus MTA(®).

AIM: To compare the in vitro biocompatibility of Biodentine™ and White ProRoot(®) mineral trioxide aggregate (MTA(®) ) with MG63 osteoblast-like cells and to characterize the cement surface. METHODOLOGY: A direct contact model for MG63 osteoblast-like cells with cements was used for 1, 3 and 5 days. Four end-points were investigated: (i) cement surface characterization by atomic force microscopy (AFM), (ii) cell viability by MTT assay, (iii) protein amount quantification by Bradford assay and (iv) cell morphology by SEM. Statistical analyses were performed by analysis of variance (anova) with a repetition test method. RESULTS: The roughness of the cements was comparable as revealed by AFM analysis. The MTT test for Biodentine™ was similar to that of MTA(®) . Biodentine™ and MTA(®) induced a similar but slight decrease in metabolic activity. The amount of total protein was significantly enhanced at day three (P < 0.05) but slightly decreased at day five for both tested samples. Biodentine™ was tolerated as well as MTA(®) in all cytotoxicity assays. SEM observations showed improvement of cell attachment and proliferation on both material surfaces following the three incubation periods. CONCLUSION: The biocompatibility of Biodentine™ to bone cells was comparable to MTA(®) .

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.

Cytotoxicity assessment of heparin nanoparticles in NR8383 macrophages.

The bioavailability of low molecular weight heparin (LMWH) has been increased by encapsulation in nanoparticles. As a complement to these results, the cytotoxicity and apoptosis induced by LMWH nanoparticles prepared by two methods [nanoprecipitation (NP) and double emulsion (DE)] using Eudragit RS (RS) and poly-epsilon-caprolactone (PCL) have been analysed. Particle sizes varied from 54 to 400nm with zeta potential values between -65 and +63mV. Our results showed that the method of nanoparticle preparation affects their properties, especially in terms of drug incorporation and cell tolerance. Cell viability ranged from 6% to 100% depending on the preparation method and physicochemical properties of the particles and the type of toxicity assay. Particle diameter and zeta potential seemed to be the most valuable cytotoxicity markers when cell viability was measured by Trypan blue exclusion and MTT respectively. Nanoparticles prepared by DE were better tolerated than those of NP. LMWH encapsulation into the cationic nanoparticles reduces remarkably their toxicity. Apoptosis evaluation showed activated caspases in exposed cells. However, no nuclear fragmentation was detected in NR8383 cells whatever the tested nanoparticles. DE nanoparticles of RS and PCL can be proposed as a good LMWH delivery system due to their low toxicity (IC(50) approximately 2.33 and 0.96mg/mL, respectively).

Internalization, cytotoxicity, apoptosis, and tumor necrosis factor-alpha expression in rat alveolar macrophages exposed to various dusts occurring in the ceramics industry.

In 1997 The International Agency for Research on Cancer classified some exposures to crystalline silica as carcinogenic to humans. Such exposures were acknowledged to be very variable, and even in the same monograph it was admitted that coal dust, containing as much as 20% quartz, could not be classified. Clearly there is a need to develop methods for assessing any risks posed by various silica containing dusts in different workplaces. A European collective research project, SILICERAM, was launched with the aim of assessing the toxicity of various dusts in the ceramics industry and improving worker protection. This study examined the effect of particles, namely, DQ12 quartz, China clay, feldspar, and a sample resembling a typical mixture used in the ceramic industry (a "contrived sample" or CS), on NR8383, a rat alveolar macrophage (AM) cell line. Titanium dioxide and aluminum oxide were also used as negative controls. Confocal microscopy observations showed internalization of DQ12 and CS in NR8383. Cell viability decreased dramatically after a 2-h incubation exposure period with DQ12 (-71%). CS was less toxic than DQ12 at 2 h. China clay and feldspar were slightly cytotoxic to NR8383 cells. DQ12 induced apoptosis, with a smaller effect of CS and China clay. TNFalpha gene expression was analyzed by RT-PCR. DQ12, at a noncytotoxic dose of 10 microg/cm(2), induced a significant expression of TNFalpha (+2 times increase). In contrast, similar doses of CS and China clay did not produce a significant increase, while TiO2 and Al2O3 displayed no effect. Co-treatment with 10 microM aluminum lactate significantly reduced the effects of silica-containing particles on cytotoxicity, apoptosis, and TNFalpha expression.