Jing-Juan Huang

Synthesis, characterization and applications of calcium carbonate/fructose 1,6-bisphosphate composite nanospheres and carbonated hydroxyapatite porous nanospheres

In this work, we first investigated the effect of fructose 1,6-bisphosphate, which is fructose sugar phosphorylated on carbons 1 and 6, on the biomineralization of calcium carbonate, and prepared calcium carbonate/fructose 1,6-bisphosphate (CC/FBP) composite nanospheres. Then, we investigated the transformation of CC/FBP composite nanospheres under microwave-assisted hydrothermal conditions and prepared carbonated hydroxyapatite (CHA) porous nanospheres. We found that FBP has a unique effect on the morphology and crystallization of calcium carbonate. FBP can control the morphology of calcium carbonate and provide the phosphorus source for the formation of CHA. The morphology and size of CC/FBP composite nanospheres can be preserved after transformation to CHA porous nanospheres under microwave-assisted hydrothermal conditions. The CC/FBP composite nanospheres and CHA porous nanospheres are efficient for anticancer drug (docetaxel) loading and release, and the drug delivery system shows a high ability to damage tumor cells, and thus is promising for application in drug delivery. The as-prepared CC/FBP composite nanospheres and CHA porous nanospheres have excellent biocompatibility and high protein adsorption capacity, as well as high efficiency for gene transfection.

Microstructure and wear properties of laser processed Ni based amorphous matrix coatings

Abstract Ni40·8Fe27·2B18Si10Nb4 (at-%) coating was deposited on mild steel substrate using high power diode laser cladding followed by laser remelting process. The phase composition and microstructures of the as cladded coating and remelted coating were analysed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The microhardness and wear properties of the coatings were also tested and analysed. It was observed that the remelted coating has an amorphous matrix embedded with some dendrites. The remelting of the coating increased the hardness of as cladded coating by ∼25%. The remelted coating exhibited a characteristically lower friction coefficient (0·21) than the as cladded coating (0·27) and the substrate (0·31). Significant increase in wear resistance was found for the remelted coating compared with the as cladded coating and the substrate under identical conditions.

Effect of laser scanning speed on TiN/TiB–Ti based composite

Abstract In situ synthesised TiN and TiB particulate reinforced metal matrix composite coating was formed on Ti–3Al–2V alloy by laser cladding with a Ti/h-BN powder mixture. The phase structure, microstructure, microhardness and wear performance of the clad layer were analysed by optical microscope, X-ray diffraction, scanning electron microscopy, microhardness tester and wear testing machine. In situ TiN and TiB were synthesised in the forms of equiaxed crystal and needle platelet/whisker type microstructures in the clad layers. The scanning speed plays an important role on the microstructure of the TiN and TiB. The microhardness of laser clad layer was 850–1250 HV0·5, which was about five times of the substrate. The wear height loss of the substrate is almost two times of the clad layers.

ASSA14-05-01 Therapeutic Ultrasound Augments Postnatal Neovascularization in Mice Model of Hindlimb Ischemia

Background Therapeutic ultrasound (TUS) has been proposed as a potential strategy to accelerate proliferation and regeneration to the damaged tissue. However, the underline mechanism remains modest clarified. The purpose of this study was to determine the mechanism of TUS on ischemia-induced angiogenesis using mice model of hindlimb ischemia. Methods and results Hindlimb ischemia was induced by unilateral femoral artery resection using 8–12 week-old male C57BL6 mice. External TUS (1.0 MHz, 0.3W/cm2) was then performed for 9 min/day. At postoperative day 14, decreased prevalence of gangrene, increased capillary density and skin temperature ratio between ischaemic/normal extremities were observed in TUS-treated mice. Moreover, the levels of nitric oxide (NO) expression, endothelial nitric oxide synthase (eNOS) and Akt phosphorylation contained in the ischaemic muscles were increased in response to TUS. In vitro, TUS interrupted the process of hypoxia-induced apoptosis and contributed to the tube-formative and proliferative capacities of human umbilical vein endothelial cells. TUS increased the level of NO in the conditioned media, as well as the eNOS and Akt phosphorylation in the cell lysate. Finally, administration of PI3K inhibitor LY294002 and NG-Nitro-L-arginine Methyl Ester (L-NAME) could block these TUS-mediated angiogenic benefits. Conclusions In conclusion, the present study indicates that external ultrasound exposure contributes to ischemia-induced neovascularization through promoting endothelial functions via Akt-eNOS signal pathway.

ASSA14-15-01 Angiogenesis effect of therapeutic ultrasound on ischaemic hind limb in mice

Background Therapeutic ultrasound (TUS) has been proposed as a potential strategy for therapeutic revascularisation. However, the specific mechanism remains to be explored in detail. The purpose of this study was to determine the mechanism of TUS on ischaemic angiogenesis in mice with acute ischaemic hind limb and proliferation, migration, tube formation and potential signalling pathways of human umbilical vein endothelial cells (HUVECs). Methods TUS was set by a combination of various ultrasound-related variables: frequency of 1.0 MHz; intensity of 0.3 W/cm2; exposure time of 3, 6, or 9 min. We stimulated the HUVECs in culture daily with TUS for 3 days. The effects of therapeutic ultrasound on HUVECs proliferation were evaluated using the CCK-8 assay. Cell migration was assayed by scratch test. Angiogenesis was observed by tube formation assay. The potential involvement of PI3K-Akt-eNOS signalling pathways was explored using selective chemical inhibitor or Western-blot analysis. Left femoral artery ligation was used to establish the model of acute hind limb ischaemic in mice (C57BL/6J male mice, 18–22 g, 2–3 months old), TUS was exposed subcutaneously once everyday for 14 days. The mice were randomly divided into four experimental groups: sham operated group; TUS 3 min group; TUS 6 min group and TUS 9 min group. The experiment was carried out on the 1st and14th after ligation. To determine whether TUS affected the angiogenesis activity of mice with ischaemic hind limb, we measured temperature of hind limb by using infrared thermometer, and microvessel density (MVD) was determined by CD31 staining. Results The results show that proliferation, migration and tube formation in HUVECs could be promoted by TUS at exposure time of 9 min, and inhibited by NG-Nitro-L-arginine Methyl Ester (L-NAME). eNOS and p-eNOS expression increased significantly when TUS 9 min was added, but could be attenuated by L-NAME. p-Akt expression augmented by TUS at exposure time of 9 min, but could be inhibited by LY294002. Compared to the temperature of hind limb, the group of TUS 9 min at the 14th was increased, while TUS 6 min group increased, but only TUS 9 min was there a significant difference. Except that, the MVD was promoted in TUS 9 min group significantly. Conclusions In conclusion, the present study indicates that 9 min of exposure to TUS promote angiogenesis among ischaemic hind limb in mice and that this process is mediated through the PI3K-Akt-eNOS signal pathway in ECs.

ASSA14-03-01 Pulsed Electromagnetic Field Improves Postnatal Neovascularization in Response to Hindlimb Ischemia

Background Pulsed electromagnetic fields (PEMF) have been shown to accelerate proliferation and regeneration to the damaged tissue, but its mechanism remains unclear. Here, we examine whether PEMF therapy improves postnatal neovascularization using murine model of hindlimb ischemia, and investigate the underlying cellular/molecular mechanisms. Methods and Results Hindlimb ischemia was induced by unilateral femoral artery resection using 6–8 week-old male C57BL6 mice. PEMF therapy (8 min/cycle, 30 ± 3 Hz, 5 mT) was then performed 4 cycles/day. At postoperative day 21, accelerated wound healing, decreased prevalence of gangrene and increased capillary density were observed among the PEMF-exposed mice. Moreover, the levels of vascular endothelial growth factor (VEGF) expression, endothelial nitric oxide synthase (eNOS) and Akt phosphorylation contained in the ischaemic muscles were increased in response to PEMF therapy. In vitro , PEMF interrupted the process of hypoxia-induced apoptosis and contributed to the tube-formative and proliferative capacities of human umbilical vein endothelial cells. PEMF exposure increased the level of VEGF in the conditioned media, as well as the eNOS and Akt phosphorylation in the cell lysate, and these PEMF-mediated angiogenic benefits could be blocked after PI3K inhibitor was administrated. Conclusions In conclusion, Our data indicated that PEMF enhanced ischemia-mediated angiogenesis, through up-regulating VEGF expression and activating the PI3K-Akt-eNOS pathway. Therefore, PEMF may be valuable for the treatment of the patients with critical limb ischemia.