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

International audienceThe 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-ɛ-caprolactone (PCL) have been analysed. Particle sizes varied from 54 to 400 nm with zeta potential values between −65 and +63 mV. 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 (IC50 ∼ 2.33 and 0.96 mg/mL, respectively)

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

The authors also wish to express their appreciation to Beatrice Burdin, PhD, at the Microstructures Technology Center of University Claude Bernard Lyon1 for assistance with the SEM study. The AFM study was supported by the Characterization of Interactions Platform of the Nanobio Program, Grenoble University. We gratefully acknowledge the assistance on the English checking from Dr Huw Jones BSc PhD MRSC, Senior Lecturer in Chemistry for Environmental Science and Public Health, Middlesex University (UK).International audienceAimTo compare the in vitro biocompatibility of Biodentine and White ProRoot((R)) mineral trioxide aggregate (MTA((R))) with MG63 osteoblast-like cells and to characterize the cement surface. MethodologyA direct contact model for MG63 osteoblast-like cells with cements was used for 1, 3 and 5days. 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. ResultsThe roughness of the cements was comparable as revealed by AFM analysis. The MTT test for Biodentine was similar to that of MTA((R)). Biodentine and MTA((R)) 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((R)) in all cytotoxicity assays. SEM observations showed improvement of cell attachment and proliferation on both material surfaces following the three incubation periods. ConclusionThe biocompatibility of Biodentine to bone cells was comparable to MTA((R))

Button battery induced cellular damage: a pathophysiological study

Button batteries (BB) are frequently swallowed and must be removed immediately as, if they remain in the esophagus, they can cause severe damage with fatal prognosis. To better understand the molecular mechanism of esophagus damage, we performed a study aimed to analyze heat production, pH variation, electrical work and metal release from BB incubated in cell culture media. Cytotoxicity and apoptosis induced in a human monocytes cell line (U937) was also investigated.Calculated transferred heat was around 244 J with a maximal increase of temperature of 7.26 K/g medium whose pH, reflecting medium electrolysis, was 12.2 after about 2 h incubation. Release of metals also occurred. Only 49.7 ± 1.9% of U937 monocytes remained viable after 90 min of incubation in DMEM containing BB. Those results suggest that BB discharge induce cytotoxicity and tissue injury probably due to multiple combinations of at least thermic, caustic and toxic phenomena. As maximal effects occurred in less than 2 h, they prompt for fast removal of battery from esophagus. Keywords: Button battery, Electrolysis, Calorimetry, Heat transfer, Metal ions, pH, Cytotoxicity, Apoptosi