Effects of Astragalus Polysaccharide on Mechanical Characterization of Liver Sinusoidal Endothelial Cells by Atomic Force Microscopy at Nanoscale.

OBJECTIVE: To study the effects of Astragalus polysaccharide (APS), the primary effective component of the Chinese herb medicine Astragalus membranaceus (frequently used for its anti-hepatic fibrosis effects), on nanoscale mechanical properties of liver sinusoidal endothelial cells (SECs). METHODS: Using endothelial cell medium as the control, 5 experimental groups were established utilizing different concentrations of APS, i.e. 12.5, 25, 50, 100, and 200 µg/mL. By using atomic force microscopy along with a microcantilever modified with a silicon dioxide microsphere as powerful tools, the value of Young's modulus in each group was calculated. SAS 9.1 software was applied to analyze the values of Young's modulus at the pressed depth of 300 nm. Environmental scanning electron microscopy was performed to observe the surface microtopography of the SECs. RESULTS: The value of Young's modulus in each APS experimental group was significantly greater than that of the control group: as APS concentration increased, the value of Young's modulus presented as an increasing trend. The difference between the low-concentration (12.5 and 25 µg/mL) and high-concentration (200 µg/mL) groups was statistically significant (P<0.05), but no significant differences were observed between moderateconcentration (50 and 100 µg/mL) groups versus low- or high-concentration groups (P>0.05). Surface topography demonstrated that APS was capable of increasing the total area of fenestrae. CONCLUSIONS: The values of Young's modulus increased along with increasing concentrations of APS, suggesting that the stiffness of SECs increases gradually as a function of APS concentration. The observed changes in SEC mechanical properties may provide a new avenue for mechanistic research of anti-hepatic fibrosis treatments in Chinese medicine.

[Research about improving flowability of powder of Chinese herbs extracts by surface modification technology].

In this study, modification technology by surface coating was used to improve the flowability of powder of Chinese herbs extracts. Seven kinds of powder of Chinese herbs extracts were coated with 1% silica nanoparticles using an under-driven Comil. The powder characteristics tester was used to evaluate the flowability of uncoated and coated powders. Surface morphology and particle size distribution of powders were compared by scanning electron microscope (SEM) and optical microscope. The powder hygroscopicity was also investigated. The results showed that, after modification, angle of repose, angle of spatula, compressibility and adhesiveness extremely decreased, and flowability index substantially increased, the powder flowability was significantly improved, especially Gegen and Dahuang extracts powders. Scanning electron microscopy images showed the distribution of silica nanoparticles on the host drug particle surfaces. There were no remarkable changes in the particle size distribution and hygroscopicity of all powders after coating. Therefore, Comilling for surface coating modification technology was an effective method to improve the flowability of Chinese herbs extracts and suggested a possible way forward to enhance the quality of Chinese drugs pharmaceutics in their study and manufacture.