Personne : Mantovani, D.
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Development and characterization of silver containing calcium phosphate coatings on pure iron foam intended for bone scaffold applications
2018-03-28, Hermawan, Hendra, Su, Yingchao, Mantovani, D., Tolouei, Ranna, Champagne, Sébastien, Trenggono, Adhitya
Despite its high structural strength and degradability, the potentiality of pure iron foam for bone scaffolds is low due to its lack of surface bioactivity. This work aims to provide a surface bioactivity to the iron foam by developing a calcium phosphate (CaP) conversion coating. Silver (Ag), known for its antibacterial property, was then incorporated onto the CaP coating via co-deposition (Ag/CaP-c) and post-treatment (Ag/CaP-p). By tuning the Ca/P ion ratio and Ag concentration during the coating process, an optimum coating parameter was obtained. All coatings were found to enhance mineralization ability and mechanical integrity of the iron foam over time. Electrochemical and immersion tests indicated that the coatings regulated the degradation rate of the iron foam via a variation of coating resistance and capacitance. Silver ions were released slowly from the Ag/CaP coating during the immersion test indicating a potential long-term antibacterial property of the coating. Details on the coating design and process optimization, the effects of three different simulated physiological solutions, and the mechanical property of the coated iron foam are discussed in this report.
Caveolin : a possible biomarker of degradable metallic materials toxicity on vascular cells
2013-03-14, Couët, Jacques, Mantovani, D., Purnama, Agung
Iron-based materials could constitute an interesting option for cardiovascular biodegradable stent applications due to their appropriate ductility compared with their counterparts, magnesium alloys. However, the predicted degradation rate of pure iron is considered to be too slow for such applications. We explored manganese (35 wt.%) as an alloying element in combination with iron to circumvent this problem through powder metallurgical processing (Fe–35Mn). Manganese, on the other hand, is highly cytotoxic. We recently explored a new method to better characterize the safety of degradable metallic materials (DMMs) by establishing the gene expression profile (GEP) of cells (mouse 3T3 fibroblasts) exposed to Fe–35Mn degradation products in order to better understand their global response to a potentially cytotoxic DMM. We identified a number of up- and down-regulated genes and confirmed the regulation of a subset of them by quantitative real time polymerase chain reaction. Caveolin-1 (cav1), the structural protein of caveolae, small, smooth plasma membrane invaginations present in various differentiated cell types, was one of the most down-regulated genes in our GEPs. In the present study we further studied the potential of this 22 kDa protein to become a biomarker for cytotoxicity after exposure to degradable metallic elements. In order to better characterize cav1 expression in this context 3T3 mouse fibroblasts were exposed to either ferrous and manganese ions at cytostatic concentrations for 24 or 48 h. cav1 gene expression was not influenced by exposure to ferrous ions. On the other hand, exposure to manganese for 24 h reduced cav1 gene expression by about 30% and by >65% after 48 h compared with control 3T3 cells. The cav1 cellular protein content was reduced to the same extent. The same pattern of expression of cav3 (the muscle-specific caveolin subtype) was also observed in this study. This strong and reproducible pattern of regulation of caveolins thus indicates potential as a biomarker for the toxicity of DMM elements.
Optical emission spectroscopy as a process-monitoring tool in plasma enhanced chemical vapor deposition of amorphous carbon coatings - multivariate statistical modelling
2018-03-01, Turgeon, Stéphane, Anooshehpour, Farid, Laroche, Gaétan, Mantovani, D., Cloutier, Maxime
Production of Diamond-Like Carbon (DLC) nanocoatings using plasma enhanced chemical vapor deposition is studied by Optical Emission Spectroscopy (OES) as a plasma diagnostic technique. The objective of the current research is to establish a predictive model of DLC properties using a multivariate analysis method. This model is based on OES data instead of process parameters, which are reactor dependent and accordingly, their effect on the plasma deposition process may vary from one reactor to another. The predictive potential of OES is evaluated using partial least square regression (PLSR) analysis. The results show that OES derived data are capable of replacing some process parameters to predict the DLC properties. The perspective of PLSR modelling and OES application for the development and monitoring of a structurally graded DLC coating is also discussed.
Gene expression profile of mouse fibroblasts exposed to a biodegradable iron alloy for stents.
2013-11-10, Couët, Jacques, Hermawan, Hendra, Mantovani, D., Purnama, Agung, Champetier, Serge.
Iron-based materials could constitute an interesting option for cardiovascular biodegradable stent applications due to their superior ductility compared to their counterparts - magnesium alloys. Since the predicted degradation rate of pure iron is considered slow, manganese (35% w/w), an alloying element for iron, was explored to counteract this problem through the powder metallurgy process (Fe-35 Mn). However, manganese presents a high cytotoxic potential; thus its effect on cells must first be established. Here, we established the gene expression profile of mouse 3T3 fibroblasts exposed to Fe-35 Mn degradation products in order to better understand cell response to potentially cytotoxic degradable metallic material (DMM). Mouse 3T3 cells were exposed to degradation products eluting through tissue culture insert filter (3 μm pore size) containing cytostatic amounts of 3.25 mg ml(-1) of Fe-35 Mn powder, 0.25 mg ml(-1) of pure Mn powder or 5 mg ml(-1) of pure iron powder for 24 h. We then conducted a gene expression profiling study from these cells. Exposure of 3T3 cells to Fe-35 Mn was associated with the up-regulation of 75 genes and down-regulation of 59 genes, while 126 were up-regulated and 76 down-regulated genes in the presence of manganese. No genes were found regulated for the iron powder. When comparing the GEP of 3T3 fibroblasts in the presence of Fe-35 Mn and Mn, 68 up-regulated and 54 down-regulated genes were common. These results were confirmed by quantitative RT-PCR for a subset of these genes. This GEP study could provide clues about the mechanism behind degradation products effects on cells of the Fe-35 Mn alloy and may help in the appraisal of its potential for DMM applications.