Understanding the mechanisms of gas transport and the resulting preferential pathways formation through bentonite-based barriers is essential for their performance evaluation.In this experimental study,gas migration w...Understanding the mechanisms of gas transport and the resulting preferential pathways formation through bentonite-based barriers is essential for their performance evaluation.In this experimental study,gas migration within a heterogenous mixture of MX80 bentonite pellets and powder with a ratio of 80/20 in dry mass was investigated.A novel X-ray transparent constant volume cell has been developed to assess the effect of gas pressure,material heterogeneities,and water vapor gas saturation on breakthrough pressure and gas pathways.The new cell allows to perform high-resolution X-ray computed micro-tomography(X-ray μCT)scans to track microstructural changes during different phases of saturation and gas injection.Experimental results showed that the gas breakthrough occurred when the pressure was raised to 3 MPa.This is slightly higher than the expected swelling pressure(2.9 MPa)of the bentonite sample.Each gas injection was followed by a long resaturation phase restoring material homogeneity at μCT resolution scale(16 mm).However,the elapsed time needed for gas to breakthrough at 3 MPa diminished at each subsequent injection test.X-ray μCT results also revealed the opening of the specimen/cell wall interface during gas passage.This opening expanded as the injection pressure increased.The gas flow along the interface was associated with the development of dilatant pathways inside the sample,although they did not reach the outlet surface.It was observed that the water vapor gas saturation had no effect on the breakthrough pressure.These findings enhance the understanding of the complex mechanisms underlying microstructural evolution and gas pathway development within the highly heterogeneous mixture.The experimental outcomes highlight the effectiveness of X-ray μCT to improve quality protocols for engineering design and safety assessments of engineered barriers.展开更多
In Switzerland,the Opalinus Clay has been selected as a potential host rock for the deep geological disposal of radioactive waste due to its low hydraulic conductivity and favorable swelling properties.During the oper...In Switzerland,the Opalinus Clay has been selected as a potential host rock for the deep geological disposal of radioactive waste due to its low hydraulic conductivity and favorable swelling properties.During the operational phase of the repository,the host rock will be exposed to pH values as high as 13.5 due to concrete degradation,which will certainly affect its hydraulic properties.This study investigates the effect of pH increase on the water retention properties of Opalinus Clay.A series of samples from the lower sandy facies of the Mont Terri site in Switzerland,at initial dry state,were exposed to a hyperalkaline solution of pH=13.5 and to the synthetic water of pH=7.5 at different water contents.After equilibrium,the total suction was measured with a dew point potentiometer and microstructural analyses were conducted via mercury intrusion porosimetry(MIP)and nitrogen adsorption-desorption technique.It was found that the total suction decreased with hydration and pH increase.Since the two investigated solutions have the same osmotic suction,the decrease in total suction was attributed to the decrease in matric suction.Indeed,the total porosity increased with saturation and pH increase.This was confirmed by MIP data that evidenced an increase in the proportion of macropores,and by Barret eJoynereHalenda(BJH)data that showed mesopore generation.The specific surface area(SSA)also increased.The previous results were due to mineral hydration and,exclusively in the case of alkaline solution,to(1)the dissolution of quartz and calcite and(2)the acid-base reactions,which were concentrated at the edges of the clay particles,leading to an increase in negatively charged groups and thus to a face-to-face association of the clay particles(dispersion),causing an increase in the repulsive forces between the clay particles.In addition,the weakening of covalent bonds led to the primary dissolution of clay minerals,i.e.silicon and aluminum detachment.展开更多
Pre-compacted elements （disks, tutus） of bentonite/sand mixture are candidate materials for sealing plugs of radioactive waste disposal. Choice of this material is mainly based on its swelling capacity allowing all ...Pre-compacted elements （disks, tutus） of bentonite/sand mixture are candidate materials for sealing plugs of radioactive waste disposal. Choice of this material is mainly based on its swelling capacity allowing all gaps in the system to be sealed, and on its low permeability. When emplaced in the gallery, these elements will start to absorb water from the host rock and swell. Thereby, a swelling pressure will develop in the radial direction against the host rock and in the axial direction against the support structure. In this work, the swelling pressure of a small scale compacted disk of bentonite and sand was experimentally studied in both radial and axial directions. Different swelling kinetics were identified for different dry densities and along different directions. As a rule, the swelling pressure starts increasing quickly, reaches a peak value, decreases a little and finally stabilises. For some dry densities, higher peaks were observed in the radial direction than in the axial direction. The presence of peaks is related to the microstructure change and to the collapse of macro- pores. In parallel to the mechanical tests, microstructure investigation at the sample scale was conducted using microfocus X-ray computed tomography （BCT）. Image observation showed a denser structure in the centre and a looser one in the border, which was also confirmed by image analysis. This structure heterogeneity in the radial direction and the occurrence of macro-pores close to the radial boundary of the sample can explain the large peaks observed in the radial swelling pressure evolution. Another interesting result is the higher anisotropy found at lower bentonite dry densities, which was also analysed by means ofμCT observation of a sample at low bentonite dry density after the end of test. It was found that the macro-pores, especially those between sand grains, were not filled by swelled bentonite, which preserved the anisotropic microstructure caused by uniaxial compression due to the absence of microstructure collapse.展开更多
Recently,the Institute for Radiological protection and Nuclear Safety(IRSN)has launched VSEAL(Vertical SEALing)project to investigate the impact of gas migration on the long-term performance of bentonite based vertica...Recently,the Institute for Radiological protection and Nuclear Safety(IRSN)has launched VSEAL(Vertical SEALing)project to investigate the impact of gas migration on the long-term performance of bentonite based vertical sealing systems(VSS).The first VSEAL in situ test was emplaced in IRSN’s Underground Research Laboratory(URL)in Tournemire(France)in 2019 and was equipped with 76 wired and wireless sensors.The test is still in progress,but the collected set of data provides already valuable information of the hydro-mechanical behavior of VSS during hydration.The swelling core consists of a mixture of highdensity pellets and powder of MX80 bentonite in a ratio of 80/20(in dry mass).An innovative method was adopted to drill a 1-m diameter and w10-m deep shaft in order to minimize the rock perturbation at the sidewalls.Because a specific protocol was adopted to install the bentonite mixture together with a careful characterization of the core during construction,VSEAL 1 constitutes the unique in situ sealing test with a well-known initial structural distribution of the pellets and the powder.Some heterogeneities occurred within the experiment during the installation process:a damaged zone developed around the shaft walls due to the interruption of the installation operations caused by COVID19 lockdown in France;a technological gap with a variable thickness between the last pellets layer and the top confining lid and a heterogeneous distribution of the bentonite powder at some layers inducing large inter pellets voids close to the bentonite-rock interface.Artificially injected water volume,relative humidity,water content and swelling pressure in both radial and axial directions were monitored.Comparison of the results showed that the presence of installation-induced heterogeneities led to the generation of preferential flow paths that influenced the swelling pressure evolution at radial and axial directions.展开更多
Background: In the context of a nuclear reactor accident, thyroid is the main target organ of radioactive iodines. To avoid as much as possible thyroid disorders or even cancer development, it is recommended to admini...Background: In the context of a nuclear reactor accident, thyroid is the main target organ of radioactive iodines. To avoid as much as possible thyroid disorders or even cancer development, it is recommended to administer a single dose of potassium iodide to people at risk of exposure. Nevertheless, the Fukushima Dai-ichi disaster has pointed out many questions about the conditions of stable iodine prophylaxis implementation highlighting the need for reflection further revision of the actual “iodine doctrine”. Therefore, providing useful data is required notably through the implementation of animal experiments to strengthen current knowledge and to edit new recommendations. Methods: Urinary iodine constitutes a very good indicator to investigate the function of thyroid, its interpretation demands reliable analyses. Prior to perform animal experiments, two calibration methods were designed by our lab and compared together (standard addition and external calibration) to assess the urinary concentration of stable iodine in urine by ICP-MS. They were validated based on several key parameters especially linearity, accuracy and limits of detection (LOD) and quantification (LOQ). Results: The results were nicely satisfying. Indeed, both calibration methods have indicated very good coefficients of correlations, accuracies with low expanded relative uncertainties were obtained. The estimated LOD in the sample for standard addition method and external calibration were fully acceptable, 0.39 μg·L-1 and 0.35 μg·L-1, respectively. All performance criteria have been thus fulfilled successfully. The established methods were proven to be accurate, robust and sensitive. Once validated, both calibration methods were applied to rat urine samples and the results of z-score and Wilcoxon W test concluded that there were no statistically significant differences between both methods.展开更多
This study aims to determine the retention time of iodinated contrast agents (ICA) in the coronary artery. The mechanical aspect of ICA displacement was studied in order to better understand the effect of these produc...This study aims to determine the retention time of iodinated contrast agents (ICA) in the coronary artery. The mechanical aspect of ICA displacement was studied in order to better understand the effect of these products on the inner wall of the artery of patients with coronary artery stenosis, undergoing repeated imaging examinations with iodinated contrast agents. ICA flow, ICA and blood flow in the artery were modelled. The fluid was regarded to be viscous, incompressible and Newtonian. Blood flow was presumed to be unidirectional, laminar and unstationary. Iodine flow velocity and retention time were calculated using the Runge-Kutta 4th order method programmed in C++ and MatLab R2013a language. The results showed that for coronary artery CT-scans, ICA retention time is 1 minute 40 seconds and for coronary arteriography it is between 2.41 and 3.61 seconds. The values calculated were compared to theoretical values and to clinical observations. The results enabled us to validate our model.展开更多
Natural organic matter(NOM)is known to play an important role in the transport and binding of trace metal elements in aquatic and soil systems.Thallium is a pollutant for which the extent of the role played by NOM is ...Natural organic matter(NOM)is known to play an important role in the transport and binding of trace metal elements in aquatic and soil systems.Thallium is a pollutant for which the extent of the role played by NOM is poorly known.Consequently,this study investigates thallium(Ⅰ)and its complexation to a purified humic substance as proxy for NOM.Experiments were performed with the Donnan Membrane Technique to separate,for the first time,the free Tl^+ion from its complexed form in the bulk solution.Various pH and concentrations were investigated at constant ionic strength and constant NOM proxy concentrations in solution.Experimental results were described with NICA-Donnan model.Thallium complexation was compared to silver complexation using literature data and using the same NICA-Donnan formalism.Parameters for these two cations(Tl^+and Ag^+)are reported in this article,for the first time.Results display low thallium complexation to the NOM proxy while silver competes with divalent cations for the NOM binding sites.Calculated speciation for dissolved thallium highlights the dominance of free thallium(Tl^+)in solution whereas Tl-NOM complexes contribute roughly 15%to total Tl(Ⅰ)species in river and lake type waters.Similar results are obtained for soil solutions,Tl-bound to NOM<30%of total,from UK soils with different land use and geochemistry.展开更多
Individual monitoring of workers exposed to the risk of intake of actinides requires suitable methods for measuring low level of excreted activity. The current protocols used for actinides analysis in bioassay are usu...Individual monitoring of workers exposed to the risk of intake of actinides requires suitable methods for measuring low level of excreted activity. The current protocols used for actinides analysis in bioassay are usually complicated and highly time consuming. In this work, a protocol based on the microwave digestion of urines followed by the separation of actinides using calix[6]arene-based chromatography columns and their measurement by a quadrupole ICP-MS is developed and validated, for the first time, on urine samples containing the three actinides, U, Pu and Am. With this protocol, the total analysis time is about 2 days, including the mineralization of urine and the chromatographic separation of actinides. Detection limits of actinides in urine are determined and compared to those obtained after “dilute and shoot” ICP-MS analysis or after alpha spectrometry measurement.展开更多
Embedding mesenchymal stromal cells(MSCs)in biomaterial is a subject of increasing interest in the field of Regenerative Medicine.Speeding up the clinical use of MSCs is dependent on the use of non-syngeneic models in...Embedding mesenchymal stromal cells(MSCs)in biomaterial is a subject of increasing interest in the field of Regenerative Medicine.Speeding up the clinical use of MSCs is dependent on the use of non-syngeneic models in accordance with Good Manufacturing Practices(GMP)requirements and on costs.To this end,in this study,we analyzed the in vivo host immune response following local injection of silanized hydroxypropyl methylcellulose(Si-HPMC)-embedded human MSCs in a rat model developing colorectal damage induced by ionizing radiation.Plasma and lymphocytes from mesenteric lymph nodes were harvested in addition to colonic tissue.We set up tests,using flow cytometry and a live imaging system,to highlight the response to specific antibodies and measure the cytotoxicity of lymphocytes against injected MSCs.We demonstrated that Si-HPMC protects MSCs from specific antibodies production and from apoptosis by lymphocytes.We also observed that Si-HPMC does not modify innate immune response infiltrate in vivo,and that in vitro co-culture of Si-HPMC-embedded MSCs impacts macrophage inflammatory response depending on the microenvironment but,more importantly,increases the macrophage regenerative response through Wnt-family and VEGF gene expression.This study furthers our understanding of the mechanisms involved,with a view to improving the therapeutic benefits of biomaterial-assisted cell therapy by modulating the host immune response.The decrease in specific immune response against injected MSCs protected by Si-HPMC also opens up new possibilities for allogeneic clinical use.展开更多
基金funding from the European Union's Horizon 2020 research and innovation program European Joint Program on RadioactiveWaste Management(EURAD)(2019e2024)WP-Gas‘Mechanistic understanding of gas transport in clay materials’under Grant agreement No.847593.
文摘Understanding the mechanisms of gas transport and the resulting preferential pathways formation through bentonite-based barriers is essential for their performance evaluation.In this experimental study,gas migration within a heterogenous mixture of MX80 bentonite pellets and powder with a ratio of 80/20 in dry mass was investigated.A novel X-ray transparent constant volume cell has been developed to assess the effect of gas pressure,material heterogeneities,and water vapor gas saturation on breakthrough pressure and gas pathways.The new cell allows to perform high-resolution X-ray computed micro-tomography(X-ray μCT)scans to track microstructural changes during different phases of saturation and gas injection.Experimental results showed that the gas breakthrough occurred when the pressure was raised to 3 MPa.This is slightly higher than the expected swelling pressure(2.9 MPa)of the bentonite sample.Each gas injection was followed by a long resaturation phase restoring material homogeneity at μCT resolution scale(16 mm).However,the elapsed time needed for gas to breakthrough at 3 MPa diminished at each subsequent injection test.X-ray μCT results also revealed the opening of the specimen/cell wall interface during gas passage.This opening expanded as the injection pressure increased.The gas flow along the interface was associated with the development of dilatant pathways inside the sample,although they did not reach the outlet surface.It was observed that the water vapor gas saturation had no effect on the breakthrough pressure.These findings enhance the understanding of the complex mechanisms underlying microstructural evolution and gas pathway development within the highly heterogeneous mixture.The experimental outcomes highlight the effectiveness of X-ray μCT to improve quality protocols for engineering design and safety assessments of engineered barriers.
文摘In Switzerland,the Opalinus Clay has been selected as a potential host rock for the deep geological disposal of radioactive waste due to its low hydraulic conductivity and favorable swelling properties.During the operational phase of the repository,the host rock will be exposed to pH values as high as 13.5 due to concrete degradation,which will certainly affect its hydraulic properties.This study investigates the effect of pH increase on the water retention properties of Opalinus Clay.A series of samples from the lower sandy facies of the Mont Terri site in Switzerland,at initial dry state,were exposed to a hyperalkaline solution of pH=13.5 and to the synthetic water of pH=7.5 at different water contents.After equilibrium,the total suction was measured with a dew point potentiometer and microstructural analyses were conducted via mercury intrusion porosimetry(MIP)and nitrogen adsorption-desorption technique.It was found that the total suction decreased with hydration and pH increase.Since the two investigated solutions have the same osmotic suction,the decrease in total suction was attributed to the decrease in matric suction.Indeed,the total porosity increased with saturation and pH increase.This was confirmed by MIP data that evidenced an increase in the proportion of macropores,and by Barret eJoynereHalenda(BJH)data that showed mesopore generation.The specific surface area(SSA)also increased.The previous results were due to mineral hydration and,exclusively in the case of alkaline solution,to(1)the dissolution of quartz and calcite and(2)the acid-base reactions,which were concentrated at the edges of the clay particles,leading to an increase in negatively charged groups and thus to a face-to-face association of the clay particles(dispersion),causing an increase in the repulsive forces between the clay particles.In addition,the weakening of covalent bonds led to the primary dissolution of clay minerals,i.e.silicon and aluminum detachment.
文摘Pre-compacted elements （disks, tutus） of bentonite/sand mixture are candidate materials for sealing plugs of radioactive waste disposal. Choice of this material is mainly based on its swelling capacity allowing all gaps in the system to be sealed, and on its low permeability. When emplaced in the gallery, these elements will start to absorb water from the host rock and swell. Thereby, a swelling pressure will develop in the radial direction against the host rock and in the axial direction against the support structure. In this work, the swelling pressure of a small scale compacted disk of bentonite and sand was experimentally studied in both radial and axial directions. Different swelling kinetics were identified for different dry densities and along different directions. As a rule, the swelling pressure starts increasing quickly, reaches a peak value, decreases a little and finally stabilises. For some dry densities, higher peaks were observed in the radial direction than in the axial direction. The presence of peaks is related to the microstructure change and to the collapse of macro- pores. In parallel to the mechanical tests, microstructure investigation at the sample scale was conducted using microfocus X-ray computed tomography （BCT）. Image observation showed a denser structure in the centre and a looser one in the border, which was also confirmed by image analysis. This structure heterogeneity in the radial direction and the occurrence of macro-pores close to the radial boundary of the sample can explain the large peaks observed in the radial swelling pressure evolution. Another interesting result is the higher anisotropy found at lower bentonite dry densities, which was also analysed by means ofμCT observation of a sample at low bentonite dry density after the end of test. It was found that the macro-pores, especially those between sand grains, were not filled by swelled bentonite, which preserved the anisotropic microstructure caused by uniaxial compression due to the absence of microstructure collapse.
文摘Recently,the Institute for Radiological protection and Nuclear Safety(IRSN)has launched VSEAL(Vertical SEALing)project to investigate the impact of gas migration on the long-term performance of bentonite based vertical sealing systems(VSS).The first VSEAL in situ test was emplaced in IRSN’s Underground Research Laboratory(URL)in Tournemire(France)in 2019 and was equipped with 76 wired and wireless sensors.The test is still in progress,but the collected set of data provides already valuable information of the hydro-mechanical behavior of VSS during hydration.The swelling core consists of a mixture of highdensity pellets and powder of MX80 bentonite in a ratio of 80/20(in dry mass).An innovative method was adopted to drill a 1-m diameter and w10-m deep shaft in order to minimize the rock perturbation at the sidewalls.Because a specific protocol was adopted to install the bentonite mixture together with a careful characterization of the core during construction,VSEAL 1 constitutes the unique in situ sealing test with a well-known initial structural distribution of the pellets and the powder.Some heterogeneities occurred within the experiment during the installation process:a damaged zone developed around the shaft walls due to the interruption of the installation operations caused by COVID19 lockdown in France;a technological gap with a variable thickness between the last pellets layer and the top confining lid and a heterogeneous distribution of the bentonite powder at some layers inducing large inter pellets voids close to the bentonite-rock interface.Artificially injected water volume,relative humidity,water content and swelling pressure in both radial and axial directions were monitored.Comparison of the results showed that the presence of installation-induced heterogeneities led to the generation of preferential flow paths that influenced the swelling pressure evolution at radial and axial directions.
基金partly supported by the French National“Investment for the future”funding programme.
文摘Background: In the context of a nuclear reactor accident, thyroid is the main target organ of radioactive iodines. To avoid as much as possible thyroid disorders or even cancer development, it is recommended to administer a single dose of potassium iodide to people at risk of exposure. Nevertheless, the Fukushima Dai-ichi disaster has pointed out many questions about the conditions of stable iodine prophylaxis implementation highlighting the need for reflection further revision of the actual “iodine doctrine”. Therefore, providing useful data is required notably through the implementation of animal experiments to strengthen current knowledge and to edit new recommendations. Methods: Urinary iodine constitutes a very good indicator to investigate the function of thyroid, its interpretation demands reliable analyses. Prior to perform animal experiments, two calibration methods were designed by our lab and compared together (standard addition and external calibration) to assess the urinary concentration of stable iodine in urine by ICP-MS. They were validated based on several key parameters especially linearity, accuracy and limits of detection (LOD) and quantification (LOQ). Results: The results were nicely satisfying. Indeed, both calibration methods have indicated very good coefficients of correlations, accuracies with low expanded relative uncertainties were obtained. The estimated LOD in the sample for standard addition method and external calibration were fully acceptable, 0.39 μg·L-1 and 0.35 μg·L-1, respectively. All performance criteria have been thus fulfilled successfully. The established methods were proven to be accurate, robust and sensitive. Once validated, both calibration methods were applied to rat urine samples and the results of z-score and Wilcoxon W test concluded that there were no statistically significant differences between both methods.
文摘This study aims to determine the retention time of iodinated contrast agents (ICA) in the coronary artery. The mechanical aspect of ICA displacement was studied in order to better understand the effect of these products on the inner wall of the artery of patients with coronary artery stenosis, undergoing repeated imaging examinations with iodinated contrast agents. ICA flow, ICA and blood flow in the artery were modelled. The fluid was regarded to be viscous, incompressible and Newtonian. Blood flow was presumed to be unidirectional, laminar and unstationary. Iodine flow velocity and retention time were calculated using the Runge-Kutta 4th order method programmed in C++ and MatLab R2013a language. The results showed that for coronary artery CT-scans, ICA retention time is 1 minute 40 seconds and for coronary arteriography it is between 2.41 and 3.61 seconds. The values calculated were compared to theoretical values and to clinical observations. The results enabled us to validate our model.
基金IRSN,CEA,BRGM and IPGP for funding this research Grant n°DEN 3841supported by IPGP multidisciplinary program PARIby Region Ile de France SESAME Grant no.12015908。
文摘Natural organic matter(NOM)is known to play an important role in the transport and binding of trace metal elements in aquatic and soil systems.Thallium is a pollutant for which the extent of the role played by NOM is poorly known.Consequently,this study investigates thallium(Ⅰ)and its complexation to a purified humic substance as proxy for NOM.Experiments were performed with the Donnan Membrane Technique to separate,for the first time,the free Tl^+ion from its complexed form in the bulk solution.Various pH and concentrations were investigated at constant ionic strength and constant NOM proxy concentrations in solution.Experimental results were described with NICA-Donnan model.Thallium complexation was compared to silver complexation using literature data and using the same NICA-Donnan formalism.Parameters for these two cations(Tl^+and Ag^+)are reported in this article,for the first time.Results display low thallium complexation to the NOM proxy while silver competes with divalent cations for the NOM binding sites.Calculated speciation for dissolved thallium highlights the dominance of free thallium(Tl^+)in solution whereas Tl-NOM complexes contribute roughly 15%to total Tl(Ⅰ)species in river and lake type waters.Similar results are obtained for soil solutions,Tl-bound to NOM<30%of total,from UK soils with different land use and geochemistry.
文摘Individual monitoring of workers exposed to the risk of intake of actinides requires suitable methods for measuring low level of excreted activity. The current protocols used for actinides analysis in bioassay are usually complicated and highly time consuming. In this work, a protocol based on the microwave digestion of urines followed by the separation of actinides using calix[6]arene-based chromatography columns and their measurement by a quadrupole ICP-MS is developed and validated, for the first time, on urine samples containing the three actinides, U, Pu and Am. With this protocol, the total analysis time is about 2 days, including the mineralization of urine and the chromatographic separation of actinides. Detection limits of actinides in urine are determined and compared to those obtained after “dilute and shoot” ICP-MS analysis or after alpha spectrometry measurement.
基金supported by the French‘Agence Nationale pour le Recherche’(Anthos project-ANR13-RPIB-008).
文摘Embedding mesenchymal stromal cells(MSCs)in biomaterial is a subject of increasing interest in the field of Regenerative Medicine.Speeding up the clinical use of MSCs is dependent on the use of non-syngeneic models in accordance with Good Manufacturing Practices(GMP)requirements and on costs.To this end,in this study,we analyzed the in vivo host immune response following local injection of silanized hydroxypropyl methylcellulose(Si-HPMC)-embedded human MSCs in a rat model developing colorectal damage induced by ionizing radiation.Plasma and lymphocytes from mesenteric lymph nodes were harvested in addition to colonic tissue.We set up tests,using flow cytometry and a live imaging system,to highlight the response to specific antibodies and measure the cytotoxicity of lymphocytes against injected MSCs.We demonstrated that Si-HPMC protects MSCs from specific antibodies production and from apoptosis by lymphocytes.We also observed that Si-HPMC does not modify innate immune response infiltrate in vivo,and that in vitro co-culture of Si-HPMC-embedded MSCs impacts macrophage inflammatory response depending on the microenvironment but,more importantly,increases the macrophage regenerative response through Wnt-family and VEGF gene expression.This study furthers our understanding of the mechanisms involved,with a view to improving the therapeutic benefits of biomaterial-assisted cell therapy by modulating the host immune response.The decrease in specific immune response against injected MSCs protected by Si-HPMC also opens up new possibilities for allogeneic clinical use.
