Surface topography is one of the key factors in regulating interactions between materials and cells.While topographies presented to cells in vivo are non-symmetrical and in complex shapes,current fabrication technique...Surface topography is one of the key factors in regulating interactions between materials and cells.While topographies presented to cells in vivo are non-symmetrical and in complex shapes,current fabrication techniques are limited to replicate these complex geometries.In this study,we developed a microcasting technique and successfully produced imprinted hydroxyapatite(HAp)surfaces with nature-inspired(honeycomb,pillars,and isolated islands)topographies.The in vitro biological performance of the developed non-symmetrical topographies was evaluated using adipose-derived stem cells(ADSCs).We demonstrated that ADSCs cultured on all HAp surfaces,except honeycomb patterns,presented well-defined stress fibers and expressed focal adhesion protein(paxillin)molecules.Isolated islands topographies significantly promoted osteogenic differentiation of ADSCs with increased alkaline phosphatase activity and upregulation of key osteogenic markers,compared to the other topographies and the control unmodified(flat)HAp surface.In contrast,honeycomb topographies hampered the ability of the ADSCs to proliferate and differentiate to the osteogenic lineage.This work presents a facile technique to imprint nature-derived topographies on the surface of bioceramics which opens up opportunities for the development of bioresponsive interfaces in tissue engineering and regenerative medicine.展开更多
Silver-containing preparations are widely used in the management of skin wounds, but the effects of silver ions on skin wound healing remain poorly understood. This study investigated the effects of silver ions （Ag^...Silver-containing preparations are widely used in the management of skin wounds, but the effects of silver ions on skin wound healing remain poorly understood. This study investigated the effects of silver ions （Ag^＋） on the proliferation of human skin keratinocytes （HaCaT） and the production of intracellular reactive oxygen species （ROS）. After treating HaCaT cells with Ag^＋ and/or the active oxygen scavenger N-acetyl cysteine （NAC）, cell proliferation and intracellular ROS generation were assessed using CCK-8 reagent and DCFH-DA fluorescent probe, respectively. In addition, 5-bromo-2-deoxyUridine （BrdU） incorporation assays, cell cycle flow cytometry, and proliferating cell nuclear antigen （PCNA） immunocytochemistry were conducted to further evaluate the effects of sub-cytotoxic Ag^＋ concentrations on HaCaT cells. The proliferation of HaCaT cells was promoted in the presence of 10^-6 and 10^-5s mol/L Ag^＋at 24, 48, and 72 h. Intracellular ROS generation also significantly increased for 5 60 min after exposure to Ag^＋ The number of BrdU-positive cells and the presence of PCNA in HaCaT cells increased 48 h after the addition of 10^-6 and 10^-5 mol/L Ag^＋, with 10^-5 mol/L Ag^＋ markedly increasing the cell proliferation index. These effects of sub-cytotoxic Ag^＋ concentrations were repressed by 5 mmol/L NAC. Our results suggest that sub-cytotoxic Ag^＋ concentrations promote the proliferation of human keratinocytes and might be associated with a moderate increase in intracellular ROS levels. This study provides important experimental evidence for developing novel silver-based wound agents or dressings with few or no cytotoxicity.展开更多
文摘Surface topography is one of the key factors in regulating interactions between materials and cells.While topographies presented to cells in vivo are non-symmetrical and in complex shapes,current fabrication techniques are limited to replicate these complex geometries.In this study,we developed a microcasting technique and successfully produced imprinted hydroxyapatite(HAp)surfaces with nature-inspired(honeycomb,pillars,and isolated islands)topographies.The in vitro biological performance of the developed non-symmetrical topographies was evaluated using adipose-derived stem cells(ADSCs).We demonstrated that ADSCs cultured on all HAp surfaces,except honeycomb patterns,presented well-defined stress fibers and expressed focal adhesion protein(paxillin)molecules.Isolated islands topographies significantly promoted osteogenic differentiation of ADSCs with increased alkaline phosphatase activity and upregulation of key osteogenic markers,compared to the other topographies and the control unmodified(flat)HAp surface.In contrast,honeycomb topographies hampered the ability of the ADSCs to proliferate and differentiate to the osteogenic lineage.This work presents a facile technique to imprint nature-derived topographies on the surface of bioceramics which opens up opportunities for the development of bioresponsive interfaces in tissue engineering and regenerative medicine.
文摘Silver-containing preparations are widely used in the management of skin wounds, but the effects of silver ions on skin wound healing remain poorly understood. This study investigated the effects of silver ions （Ag^＋） on the proliferation of human skin keratinocytes （HaCaT） and the production of intracellular reactive oxygen species （ROS）. After treating HaCaT cells with Ag^＋ and/or the active oxygen scavenger N-acetyl cysteine （NAC）, cell proliferation and intracellular ROS generation were assessed using CCK-8 reagent and DCFH-DA fluorescent probe, respectively. In addition, 5-bromo-2-deoxyUridine （BrdU） incorporation assays, cell cycle flow cytometry, and proliferating cell nuclear antigen （PCNA） immunocytochemistry were conducted to further evaluate the effects of sub-cytotoxic Ag^＋ concentrations on HaCaT cells. The proliferation of HaCaT cells was promoted in the presence of 10^-6 and 10^-5s mol/L Ag^＋at 24, 48, and 72 h. Intracellular ROS generation also significantly increased for 5 60 min after exposure to Ag^＋ The number of BrdU-positive cells and the presence of PCNA in HaCaT cells increased 48 h after the addition of 10^-6 and 10^-5 mol/L Ag^＋, with 10^-5 mol/L Ag^＋ markedly increasing the cell proliferation index. These effects of sub-cytotoxic Ag^＋ concentrations were repressed by 5 mmol/L NAC. Our results suggest that sub-cytotoxic Ag^＋ concentrations promote the proliferation of human keratinocytes and might be associated with a moderate increase in intracellular ROS levels. This study provides important experimental evidence for developing novel silver-based wound agents or dressings with few or no cytotoxicity.
