Magnesium-based materials show great potential for producing biodegradable stents,but their high corrosion rates are a roadblock.This study investigates whether ultrasound melt treatment can change the corrosion respo...Magnesium-based materials show great potential for producing biodegradable stents,but their high corrosion rates are a roadblock.This study investigates whether ultrasound melt treatment can change the corrosion response of an extruded AZ91D-1.0%Ca(wt.%)in Earle's Balanced Salt Solution by tailoring the intermetallics'morphology in the as-extruded state.The results showed that the wires from ultrasound-treated ingots corroded faster than non-treated ones in immersion for up to 6 hours.This trend shifted for longer periods,and ultrasound-treated material showed lower corrosion rates and uniform corrosion,while the non-treated material displayed localized corrosion signs.Tensile testing of the wires demonstrated that immersion in EBSS lowered the tensile strength and elongation at fracture due to material degradation,regardless of the processing route.Nonetheless,this decline was sharper in the non-treated material.These findings suggest that ultrasound melt processing can be a promising method for improving the corrosion resistance of magnesium-based materials,paving the way for their use in manufacturing biodegradable stents.展开更多
This study investigated the osteogenic performance of new brushite cements obtained from Li+-dopedβ-tricalcium phosphate as a promising strategy for bone regeneration.Lithium(Li+)is a promising trace element to encou...This study investigated the osteogenic performance of new brushite cements obtained from Li+-dopedβ-tricalcium phosphate as a promising strategy for bone regeneration.Lithium(Li+)is a promising trace element to encourage the migration and proliferation of adipose-derived stem cells(hASCs)and the osteogenic differentiation-related gene expression,essential for osteogenesis.In-situ X-ray diffraction(XRD)and in-situ 1H nuclear magnetic resonance(1H NMR)measurements proved the precipitation of brushite,as main phase,and monetite,indicating that Li+favored the formation of monetite under certain conditions.Li+was detected in the remaining pore solution in significant amounts after the completion of hydration.Isothermal calorimetry results showed an accelerating effect of Li+,especially for low concentration of the setting retarder(phytic acid).A decrease of initial and final setting times with increasing amount of Li+was detected and setting times could be well adjusted by varying the setting retarder concentration.The cements presented compressive mechanical strength within the ranges reported for cancellous bone.In vitro assays using hASCs showed normal metabolic and proliferative levels.The immunodetection and gene expression profile of osteogenic-related markers highlight the incorporation of Li+for increasing the in vivo bone density.The osteogenic potential of Li-doped brushite cements may be recommended for further research on bone defect repair strategies.展开更多
Surface topographies of cell culture substrates can be used to generate in vitro cell culture environments similar to the in vivo cell niches. In vivo, the physical properties of the extracellular matrix (ECM), such a...Surface topographies of cell culture substrates can be used to generate in vitro cell culture environments similar to the in vivo cell niches. In vivo, the physical properties of the extracellular matrix (ECM), such as its topography, provide physical cues that play an important role in modulating cell function. Mimicking these properties remains a challenge to provide in vitro realistic environments for cells. Artificially generated substrates’ topographies were used extensively to explore this important surface cue. More recently, the replication of natural surface topographies has been enabling to exploration of characteristics such as hierarchy and size scales relevant for cells as advanced biomimetic substrates. These substrates offer more realistic and mimetic environments regarding the topographies found in vivo. This review will highlight the use of natural surface topographies as a template to generate substrates for in-vitro cell culture. This review starts with an analysis of the main cell functions that can be regulated by the substrate’s surface topography through cell-substrate interactions. Then, we will discuss research works wherein substrates for cell biology decorated with natural surface topographies were used and investigated regarding their influence on cellular performance. At the end of this review, we will highlight the advantages and challenges of the use of natural surface topographies as a template for the generation of advanced substrates for cell culture.展开更多
基金This work was supported by Portuguese FCT under the project UIDB/04436/2020the doctoral grant PD/BD/140094/2018 and SFRH/BD/145285/2019.
文摘Magnesium-based materials show great potential for producing biodegradable stents,but their high corrosion rates are a roadblock.This study investigates whether ultrasound melt treatment can change the corrosion response of an extruded AZ91D-1.0%Ca(wt.%)in Earle's Balanced Salt Solution by tailoring the intermetallics'morphology in the as-extruded state.The results showed that the wires from ultrasound-treated ingots corroded faster than non-treated ones in immersion for up to 6 hours.This trend shifted for longer periods,and ultrasound-treated material showed lower corrosion rates and uniform corrosion,while the non-treated material displayed localized corrosion signs.Tensile testing of the wires demonstrated that immersion in EBSS lowered the tensile strength and elongation at fracture due to material degradation,regardless of the processing route.Nonetheless,this decline was sharper in the non-treated material.These findings suggest that ultrasound melt processing can be a promising method for improving the corrosion resistance of magnesium-based materials,paving the way for their use in manufacturing biodegradable stents.
基金funded by the Portuguese Foundation for Science and Technology(FCT)and the German Academic Exchange Service(Deutscher Akademischer Austauschdienst,DAAD)for the transnational cooperation FCT/DAAD 2018-2019FRM acknowledges her contract under the Transitional Rule DL 57/2016(CTTI-57/18-I3BS(5))attributed by the FCT.VPR acknowledges the Junior Researcher contracts(POCI-01-0145-FEDER-031367+1 种基金POCI-01-0145-FEDER-029139)under the projects Fun4TE project(PTDC/EMD-EMD/31367/2017)and B-Liver(PTDC/EMD-EMD/29139/2017)attributed by the FCT.The authors also thank the funds provided under the distinctions attributed to JMO(IF/01285/2015)and SP(CEECIND/03673/2017).Furthermore,funding by the German Research Foundation(Deutsche Forschungsgemeinschaft,DFG),Grant Nr.HU 2498/1-1GB 1/22-1,is acknowledged.
文摘This study investigated the osteogenic performance of new brushite cements obtained from Li+-dopedβ-tricalcium phosphate as a promising strategy for bone regeneration.Lithium(Li+)is a promising trace element to encourage the migration and proliferation of adipose-derived stem cells(hASCs)and the osteogenic differentiation-related gene expression,essential for osteogenesis.In-situ X-ray diffraction(XRD)and in-situ 1H nuclear magnetic resonance(1H NMR)measurements proved the precipitation of brushite,as main phase,and monetite,indicating that Li+favored the formation of monetite under certain conditions.Li+was detected in the remaining pore solution in significant amounts after the completion of hydration.Isothermal calorimetry results showed an accelerating effect of Li+,especially for low concentration of the setting retarder(phytic acid).A decrease of initial and final setting times with increasing amount of Li+was detected and setting times could be well adjusted by varying the setting retarder concentration.The cements presented compressive mechanical strength within the ranges reported for cancellous bone.In vitro assays using hASCs showed normal metabolic and proliferative levels.The immunodetection and gene expression profile of osteogenic-related markers highlight the incorporation of Li+for increasing the in vivo bone density.The osteogenic potential of Li-doped brushite cements may be recommended for further research on bone defect repair strategies.
基金This work is a result of the project FROnTHERA(NORTE-01-0145-FEDER-000023)supported by Norte Portugal Regional Operational Programme(NORTE 2020)+3 种基金under the PORTUGAL 2020 Partnership Agreement,through the European Regional Development Fund(ERDF)Portuguese Foundation for Science and Technology under the doctoral programme in Tissue Engineering,Regenerative Medicine and Stem Cells(PD/59/2013)(PD/BD/128087/2016)by the project Cells4_IDs(PTDC/BTM-SAL/28882/2017).
文摘Surface topographies of cell culture substrates can be used to generate in vitro cell culture environments similar to the in vivo cell niches. In vivo, the physical properties of the extracellular matrix (ECM), such as its topography, provide physical cues that play an important role in modulating cell function. Mimicking these properties remains a challenge to provide in vitro realistic environments for cells. Artificially generated substrates’ topographies were used extensively to explore this important surface cue. More recently, the replication of natural surface topographies has been enabling to exploration of characteristics such as hierarchy and size scales relevant for cells as advanced biomimetic substrates. These substrates offer more realistic and mimetic environments regarding the topographies found in vivo. This review will highlight the use of natural surface topographies as a template to generate substrates for in-vitro cell culture. This review starts with an analysis of the main cell functions that can be regulated by the substrate’s surface topography through cell-substrate interactions. Then, we will discuss research works wherein substrates for cell biology decorated with natural surface topographies were used and investigated regarding their influence on cellular performance. At the end of this review, we will highlight the advantages and challenges of the use of natural surface topographies as a template for the generation of advanced substrates for cell culture.
