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In order to investigate in greater detail the two methods based on Hertz model for analyzing force-distance curve obtained by atomic force microscopy, we acquired the force-distance curves of Hela and MCF-7 cells by atomic force microscopy (AFM) indentation in this study. After the determination of contact point, Young's modulus in different indentation depth were calculated with two analysis methods of "two point" and "slope fitting". The results showed that the Young's modulus of Hela cell was higher than that of MCF-7 cell,which is in accordance with the F-actin distribution of the two types of cell. We found that the Young's modulus of the cells was decreased with increasing indentation depth and the curve trends by "slope fitting". This indicated that the "slope fitting" method could reduce the error caused by the miscalculation of contact point. The purpose of this study was to provide a guidance for researcher to choose an appropriate method for analyzing AFM indentation force-distance curve.

Objective: To investigate effects of collagen matrices by covalent incorporation of heparin and loading with huangqi injection (HI) on anagenetic capillaries, we established the chick chorioallantois model. The collagen matrices by covalent incorporation of heparin and loading with HI were placed and then the eggs were continuously incubated for 3 days. The number of capillaries in the vicinity of samples, the hemoglobin content inside the samples, the dry weight and the macroscopic observation were evaluated. We found the heparinized matrices had comparable angiogenic effects. The number of capillaries, the hemoglobin content, the expression of CD34 increased remarkably (P < 0.01). So we concluded that HI might be considered as an alternative or addition agent to promote the acidification of capillaries.