Plasma-immersion ion implantation (PIII) is a technique for implanting ions into conducting, semiconducting and insulating objects. In PIII, the object being treated is immersed in a plasma and pulsed to a large negat...Plasma-immersion ion implantation (PIII) is a technique for implanting ions into conducting, semiconducting and insulating objects. In PIII, the object being treated is immersed in a plasma and pulsed to a large negative voltage (=-1 to-100 kV). The resulting sheath expands into the ambient plasma, extracting ions and accelerating them to the target. PIII has advantages over beam-line implantation in that large surfaces can be rapidly implanted, irregularly-shaped objects can be implanted without target manipulation, and surfaces that are not line-of-sight accessible can be treated. A two-dimensional, self-consistent model of plasma dynamics appropriate for PIII is described. The model is a hybrid, with Boltzmann electrons and kinetic ions, where the ion Vlasov equation is solved using the particle-in-cell (PIC) method. Solutions of the model give the time dependence of the ion flux, energy and impact angle at the target surface, together with the evolution of the sheath.展开更多
This study reports a hybrid method which allows the formation of biocomposites on stainless steel implants. The main idea of the method is to create multilayer coatings consisting of titanium primer layer and a microa...This study reports a hybrid method which allows the formation of biocomposites on stainless steel implants. The main idea of the method is to create multilayer coatings consisting of titanium primer layer and a microarc calcium-phosphate coating. The titanium layer is deposited from plasma of continuous vacuum-arc discharge, and calcium-phosphate coating is formed by the microarc oxidation technique. The purpose of the hybrid method is to combine the properties of good strength stainless steel with high bioactivity of calcium-phosphate coating. This paper describes the chemical composition, morphology characteristics, adhesion and the ability of the formed biocomposites to stimulate the processes of osteoinduction. It is expedient to use such biocomposites for implants which carry heavy loads and are intended for long-term use, e.g. total knee endoprosthesis.展开更多
Many biological structures such as nerves,blood and lymphatic vessels,and muscle fibres exhibit longitudinal ge-ometries with distinct cell types extending along both the length and width of internal linear axes.Model...Many biological structures such as nerves,blood and lymphatic vessels,and muscle fibres exhibit longitudinal ge-ometries with distinct cell types extending along both the length and width of internal linear axes.Modelling these three-dimensional structures in vitro is challenging:the best-defined stem-cell differentiation systems are mono-layer cultures or organoids using pluripotent stem cells.Pluripotent stem cells can differentiate into functionally mature cells depending on the signals received,holding great promise for regenerative medicine.However,the integration of in vitro differentiated cell types into diseased tissue remains a challenge.Engineered scaffolds can bridge this gap if the appropriate signalling systems are incorporated into the scaffold.Here,we have taken a biomimicry approach to generate longitudinal structures in vitro.In this approach,mouse embryonic stem cells are directed to differentiate to specific cell types on the surface of polycaprolactone(PCL)fibres treated by plasma-immersion ion implantation and to which with lineage-specifying molecules have been covalently im-mobilised.We demonstrate the simplicity and utility of our method for efficiently generating high yields of the following cell types from these pluripotent stem cells:neurons,vascular endothelial cells,osteoclasts,adipocytes,and cells of the erythroid,myeloid,and lymphoid lineages.Strategically arranged plasma-treated scaffolds with differentiated cell types could ultimately serve as a means for the repair or treatment of diseased or damaged tissue.展开更多
文摘Plasma-immersion ion implantation (PIII) is a technique for implanting ions into conducting, semiconducting and insulating objects. In PIII, the object being treated is immersed in a plasma and pulsed to a large negative voltage (=-1 to-100 kV). The resulting sheath expands into the ambient plasma, extracting ions and accelerating them to the target. PIII has advantages over beam-line implantation in that large surfaces can be rapidly implanted, irregularly-shaped objects can be implanted without target manipulation, and surfaces that are not line-of-sight accessible can be treated. A two-dimensional, self-consistent model of plasma dynamics appropriate for PIII is described. The model is a hybrid, with Boltzmann electrons and kinetic ions, where the ion Vlasov equation is solved using the particle-in-cell (PIC) method. Solutions of the model give the time dependence of the ion flux, energy and impact angle at the target surface, together with the evolution of the sheath.
文摘This study reports a hybrid method which allows the formation of biocomposites on stainless steel implants. The main idea of the method is to create multilayer coatings consisting of titanium primer layer and a microarc calcium-phosphate coating. The titanium layer is deposited from plasma of continuous vacuum-arc discharge, and calcium-phosphate coating is formed by the microarc oxidation technique. The purpose of the hybrid method is to combine the properties of good strength stainless steel with high bioactivity of calcium-phosphate coating. This paper describes the chemical composition, morphology characteristics, adhesion and the ability of the formed biocomposites to stimulate the processes of osteoinduction. It is expedient to use such biocomposites for implants which carry heavy loads and are intended for long-term use, e.g. total knee endoprosthesis.
基金supported by the Australian Research Council Laureate and Discovery fundings[FL190100216,DP190103507 and DE210100662]the University of Sydney School of Physics“Grand Challenge”program.
文摘Many biological structures such as nerves,blood and lymphatic vessels,and muscle fibres exhibit longitudinal ge-ometries with distinct cell types extending along both the length and width of internal linear axes.Modelling these three-dimensional structures in vitro is challenging:the best-defined stem-cell differentiation systems are mono-layer cultures or organoids using pluripotent stem cells.Pluripotent stem cells can differentiate into functionally mature cells depending on the signals received,holding great promise for regenerative medicine.However,the integration of in vitro differentiated cell types into diseased tissue remains a challenge.Engineered scaffolds can bridge this gap if the appropriate signalling systems are incorporated into the scaffold.Here,we have taken a biomimicry approach to generate longitudinal structures in vitro.In this approach,mouse embryonic stem cells are directed to differentiate to specific cell types on the surface of polycaprolactone(PCL)fibres treated by plasma-immersion ion implantation and to which with lineage-specifying molecules have been covalently im-mobilised.We demonstrate the simplicity and utility of our method for efficiently generating high yields of the following cell types from these pluripotent stem cells:neurons,vascular endothelial cells,osteoclasts,adipocytes,and cells of the erythroid,myeloid,and lymphoid lineages.Strategically arranged plasma-treated scaffolds with differentiated cell types could ultimately serve as a means for the repair or treatment of diseased or damaged tissue.
