The electrical characterization of bone is essential for the better understanding of the role of electrical stimulation in bone remodeling. Calcium Hydrogen Phosphate Dihydrate or brushite (CaHPO4 2H2O) has been used ...The electrical characterization of bone is essential for the better understanding of the role of electrical stimulation in bone remodeling. Calcium Hydrogen Phosphate Dihydrate or brushite (CaHPO4 2H2O) has been used in bone substitution owing to their fast resorption under physiological condition. Brushite is a suitable matrix for osteoconductive bone grafts. In this work, Calcium Hydrogen Phosphate single crystals have been grown by single diffusion gel growth technique. The powder XRD studies revealed the monoclinic structure of the grown crystals. The vibrational analysis of the crystals is done with FTIR spectroscopy and the major functional groups and their assigned vibrations are discussed. The frequency dependence of dielectric constant and ac conductivity at different temperatures have been studied in detail. This study shows decrease in the dielectric constant with the increase in frequency and temperature. The variation of ac conductivity is found to be increasing with frequency and decreasing with temperature.展开更多
For the past several years,calcium phosphate cement was used in the biomedical applications.Outstanding biocompatibility,good bioactivity,self-setting qualities,minimum setting degree,appropriate toughness,and simple ...For the past several years,calcium phosphate cement was used in the biomedical applications.Outstanding biocompatibility,good bioactivity,self-setting qualities,minimum setting degree,appropriate toughness,and simple shape to accommodate any difficult geometry are among their most notable attributes.Calcium phosphate has some types and brushite is one of the most attractive mineral for bone repair application.Brushite is extensively employed in filling fractures and trauma treatments as a bone substituted material.This kind of material can potentially be used as a medicine delivery device.The replacement of metal,such as magnesium,zinc,and strontium ions,into the calcium phosphate structure is a major research topic these days.Brushite cement has low mechanical strength and quick setting rate.It is possible to produce biomaterials with higher mechanical characteristics.By adding metal that are great potential in controlling cellular density when included into biomaterials.As a result,it is a successful method to develop quite well regenerative medicine.This paper provides a detailed summary of the present achievements of metal-doped brushite cement for bone repair and healing process.The major purpose of this work is to give a simple but thorough analysis of current successes in brushite cement doped with Zn,Mg,Sr,and other ions as well as to highlight new advancements and prospects.The impact of metal replacement on cement physical and chemical properties,including microstructure,setting time,injectability,mechanical property,and ion release,is explored.The metal-doped cement has osteogenesis,angiogenesis,and antibacterial properties,as well as their prospective utility as drug carriers,also considered.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
Calcium hydrogen phosphate dihydrate (CHPD, CaHPO4· 2H2O) or brushite is found quite frequently in urinary calculi (stones). Crystallization of brushite has been carried out in sodium metasilicate (SMS) gel with ...Calcium hydrogen phosphate dihydrate (CHPD, CaHPO4· 2H2O) or brushite is found quite frequently in urinary calculi (stones). Crystallization of brushite has been carried out in sodium metasilicate (SMS) gel with and without adding ‘Sr’ as additive. In pure system, dicalcium phosphate anhydrous (DCPA, CaHPO4) or monetite and hydroxyapatite (HA, Ca5(PO4)3(OH)) grew along with brushite. The presence of Sr suppressed the formation of HA and enhanced the number and size of monetite crystals and changed the morphology of brushite crystals from needle shape to octopus-like shape. The samples were characterized by powder & single crystal X-ray diffraction (XRD), scanning electron microscopy (SEM), Xray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR) and thermal analyses (TG-DTA).展开更多
In a previous study, the authors tried to synthesize dental materials from dental waste, which was accomplished with alginate impression materials and gypsum. A powder was set by mixing it with phosphate solution. Fib...In a previous study, the authors tried to synthesize dental materials from dental waste, which was accomplished with alginate impression materials and gypsum. A powder was set by mixing it with phosphate solution. Fibrous curled crystals were found through SEM observation. The present study shows a detailed analysis of the crystals. XRD analysis indicated the crystals are Brushite. A unique profile of the crystal shows it can be a good apatite precursor or cell scaffold;however, this hypothesis requires further examination.展开更多
Calcium phosphate cements are of great interest for researchers and their applications in medical practice expanded.Nevertheless,they have a number of drawbacks including the insufficient level of mechanical propertie...Calcium phosphate cements are of great interest for researchers and their applications in medical practice expanded.Nevertheless,they have a number of drawbacks including the insufficient level of mechanical properties and low degradation rate.Struvite(MgNH4PO4)-based cements,which grew in popularity in recent years,despite their neutral pH and acceptable mechanical performance,release undesirable NH4+ions during their resorption.This issue could be avoided by replacement of ammonia ions in the cement liquid with sodium,however,such cements have a pH values of 9–10,leading to cytotoxicity.Thus,the main goal of this investigation is to optimize the composition of cements to achieve the combination of desirable properties:neutral pH,sufficient mechanical properties,and the absence of cytotoxicity,applying Na2HPO4-based cement liquid.For this purpose,cement powders precursors in the CaO-MgO-P2O5 system were synthesized by one-pot process in a wide composition range,and their properties were investigated.The optimal performance was observed for the cements with(Ca+Mg)/P ratio of 1.67,which are characterized by newberyite phase formation during setting reaction,pH values close to 7,sufficient compressive strength up to 22±3 MPa(for 20 mol.%of Mg),dense microstructure and adequate matrix properties of the surface.This set of features make those materials promising candidates for medical applications.展开更多
文摘The electrical characterization of bone is essential for the better understanding of the role of electrical stimulation in bone remodeling. Calcium Hydrogen Phosphate Dihydrate or brushite (CaHPO4 2H2O) has been used in bone substitution owing to their fast resorption under physiological condition. Brushite is a suitable matrix for osteoconductive bone grafts. In this work, Calcium Hydrogen Phosphate single crystals have been grown by single diffusion gel growth technique. The powder XRD studies revealed the monoclinic structure of the grown crystals. The vibrational analysis of the crystals is done with FTIR spectroscopy and the major functional groups and their assigned vibrations are discussed. The frequency dependence of dielectric constant and ac conductivity at different temperatures have been studied in detail. This study shows decrease in the dielectric constant with the increase in frequency and temperature. The variation of ac conductivity is found to be increasing with frequency and decreasing with temperature.
基金The authors are grateful to the University of Engineering and Technology,Lahore,Pakistan(ORIC/99 ASRB-614)for funding this research.
文摘For the past several years,calcium phosphate cement was used in the biomedical applications.Outstanding biocompatibility,good bioactivity,self-setting qualities,minimum setting degree,appropriate toughness,and simple shape to accommodate any difficult geometry are among their most notable attributes.Calcium phosphate has some types and brushite is one of the most attractive mineral for bone repair application.Brushite is extensively employed in filling fractures and trauma treatments as a bone substituted material.This kind of material can potentially be used as a medicine delivery device.The replacement of metal,such as magnesium,zinc,and strontium ions,into the calcium phosphate structure is a major research topic these days.Brushite cement has low mechanical strength and quick setting rate.It is possible to produce biomaterials with higher mechanical characteristics.By adding metal that are great potential in controlling cellular density when included into biomaterials.As a result,it is a successful method to develop quite well regenerative medicine.This paper provides a detailed summary of the present achievements of metal-doped brushite cement for bone repair and healing process.The major purpose of this work is to give a simple but thorough analysis of current successes in brushite cement doped with Zn,Mg,Sr,and other ions as well as to highlight new advancements and prospects.The impact of metal replacement on cement physical and chemical properties,including microstructure,setting time,injectability,mechanical property,and ion release,is explored.The metal-doped cement has osteogenesis,angiogenesis,and antibacterial properties,as well as their prospective utility as drug carriers,also considered.
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.
文摘Calcium hydrogen phosphate dihydrate (CHPD, CaHPO4· 2H2O) or brushite is found quite frequently in urinary calculi (stones). Crystallization of brushite has been carried out in sodium metasilicate (SMS) gel with and without adding ‘Sr’ as additive. In pure system, dicalcium phosphate anhydrous (DCPA, CaHPO4) or monetite and hydroxyapatite (HA, Ca5(PO4)3(OH)) grew along with brushite. The presence of Sr suppressed the formation of HA and enhanced the number and size of monetite crystals and changed the morphology of brushite crystals from needle shape to octopus-like shape. The samples were characterized by powder & single crystal X-ray diffraction (XRD), scanning electron microscopy (SEM), Xray fluorescence spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR) and thermal analyses (TG-DTA).
文摘In a previous study, the authors tried to synthesize dental materials from dental waste, which was accomplished with alginate impression materials and gypsum. A powder was set by mixing it with phosphate solution. Fibrous curled crystals were found through SEM observation. The present study shows a detailed analysis of the crystals. XRD analysis indicated the crystals are Brushite. A unique profile of the crystal shows it can be a good apatite precursor or cell scaffold;however, this hypothesis requires further examination.
基金financially support by Russian Foundation for Basic Research(Grant No.18-33-20170).
文摘Calcium phosphate cements are of great interest for researchers and their applications in medical practice expanded.Nevertheless,they have a number of drawbacks including the insufficient level of mechanical properties and low degradation rate.Struvite(MgNH4PO4)-based cements,which grew in popularity in recent years,despite their neutral pH and acceptable mechanical performance,release undesirable NH4+ions during their resorption.This issue could be avoided by replacement of ammonia ions in the cement liquid with sodium,however,such cements have a pH values of 9–10,leading to cytotoxicity.Thus,the main goal of this investigation is to optimize the composition of cements to achieve the combination of desirable properties:neutral pH,sufficient mechanical properties,and the absence of cytotoxicity,applying Na2HPO4-based cement liquid.For this purpose,cement powders precursors in the CaO-MgO-P2O5 system were synthesized by one-pot process in a wide composition range,and their properties were investigated.The optimal performance was observed for the cements with(Ca+Mg)/P ratio of 1.67,which are characterized by newberyite phase formation during setting reaction,pH values close to 7,sufficient compressive strength up to 22±3 MPa(for 20 mol.%of Mg),dense microstructure and adequate matrix properties of the surface.This set of features make those materials promising candidates for medical applications.