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Objective@#To explore the effects of shear stress on morphology, adhesion and proliferation of human umbilical cord blood mesenchymal stem cells(hUC-MSCs).@*Methods@#The hUC-MSCs were cultured in vitro until confluence and then placed in a flow system.The cells were subjected to different shear stress (1, 2, 3, 4 dye/cm2) for 2 hours and 6 hours, and no shear stress treatment cells served as a static control.The morphological changes of hUC-MSCs in different groups were analyzed by phase contrast microscopy and immunofluorescence.The mRNA expression levels of intercellular adhesion molecule-1 (ICAM-1) and Ki67 were detected by real-time PCR.@*Results@#Compared with the static control group, the hUC-MSCs cells were arranged in the direction of fluid after treated with shear stress.The immunofluorescence results showed that the cytoskeletal protein F-actin filaments was prolonged after shear stress.The cytoskeleton was further elongated in the 2 dye/cm2 for 6 hours group when compared with 2 dye/cm2 for 2 hours group, and the cytoskeleton was loosened when time extended to 6 hours.Real-time PCR results showed that the relative expressions of ICAM-1 mRNA and Ki67 mRNA in the static control group and different gradient shear stress groups were significantly different, with significant differences among them (F=17.141, P=0.000; F=11.336, P=0.001). The relative expression of ICAM-1 mRNA in the 1, 2, 3, 4 dye/cm2 shear stress group was 2.74±0.32, 9.77±1.19, 6.70±0.92 and 5.69±0.72, respectively, which was significantly higher than 1.00±0.28 in the static control group, with significant differences between them (all at P<0.05). The relative expression of Ki67 mRNA in the 3 dye/cm2 and 4 dye/cm2 shear stress group was 0.39±0.09 and 0.04±0.02, respectively, which was significantly lower than 1.00±0.24 in the static control group, with statistically significant differences between them (both at P<0.05).@*Conclusions@#After treated with fluid shear stress, hUC-MSCs are arranged in the direction of fluid.Shear stress can promote the adhesion of hUC-MSCs.As the increase of shear stress intensity, cell proliferation is inhibited.
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Objective To investigate the selective targeting ability of a novel folate-modified nanobubbles with two-fold amount of folate [(FOL)2-NBs] . Methods DSPE-PEG2000-AD-(FOL)2with two-fold of folate per DSPE-PEG2000 chain was synthesized and then tested by 1 H nuclear magnetic resonance (1H NMR) . The novel (FOL)2-NBs was prepared using the mechanical shaking method based on lipid-stabilized perfluoropropane . The bubble size was measured by Malvern laser particle size analyzer and the contrast enhancement ability was also detected with imaging machine using a self-made agarose mold . The experiment of selective targeting ability was also carried out in human breast cancer MCF-7 cell with over-expression of folate receptor ( FR) using fluorescence activated cell sorting ( FACS) . Results The result of 1H NMR proved that DSPE-PEG2000-AD-( FOL )2was successfully synthesized ,and the purity reached up to 90% . The novel prepared ( FOL) 2-NBs showed superior contrast enhancement ability with a particle size of ( 286 .87 ± 22 .96) nm . Compared with the conventional NBs ,the novel ( FOL) 2-NBs exhibited improved selective cellular targeting ability proven by FACS . Conclusions A novel nanobubble with improved selective targeting ability is successfully prepared and shows great potential in extravascular imaging and curation in FR overexpressed tumors .
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Objective To explore the bioeffect of different parameters on 4 cell lines by ultrasoundmediated microbubble destruction.Methods The orthogonal experimental design was used to investigate the effect of three factors on the bioeffects of four cell lines under three levels.Three factors included microbubble concentration,sound intensity,irradiation time.Human breast tumor (MCF-7) cells,ovarian tumor (A2780) cells,liver tumor (Bel7402) cells and thyroid tumor (ARO) cells were exposed to ultrasound in the presence of SonoVue.The cell survival rate was determined by MTT methods and the cell luminosity factor was detected by flow cytometry.Results The optimum parameters for Bel7402 and ARO cell were the same (A2B3C2),and they were different from those from MCF-7 (A3B1C1) and A2780 (A1B3C3) cell.The cell survival rates for 4 cell lines were above 75％,and the cell luminosity factors were different among 4 cell lines.Conclusions The optimum parameters by ultrasound-mediated microbubble destruction for different cell lines are different,and under the optimum parameters the bioeffects of different cell lines are different.