Adsorption thermodynamics and kinetics of nanomaterials: theory and experimental insight into nano-effect.

Nanomaterials have excellent adsorption performance due to nano-effect and have been widely used in many fields. The adsorption performance of nanomaterials depends on their adsorption thermodynamics and kinetics. Here, the thermodynamic and kinetic equations of adsorption for spherical nanoparticles are first derived in theory. The mechanisms and regularities of influences of nano-effect on thermodynamics and kinetics, using nano-CdS adsorption of methylene blue as a probe, were investigated. The results show that there are significant influences of nano-effect (i.e., interface area effect and interface tension effect) on the thermodynamics and kinetics of nanoparticle adsorption. When the particle radius is larger and beyond the nanometer scale (∼100 nm), the nano-effect can be neglected. When the radius of the nanoparticle is within 10-50 nm, the nano-effect of adsorption is mainly the interface area effect. When the radius is less than 10 nm, the influences of both the interface area effect and the interface tension effect on adsorption thermodynamics and kinetics become more significant. The theoretic equations and experimental insights in the present work could provide a significant basis and reference for improving and perfecting the adsorption theory involving nanomaterials and provide guidelines for the explanations of adsorption mechanisms as well as the selection of adsorbents.

Inhibitory effect of astragalus membranaceus injection on apoptosis and autophagy induced by enterovirus 71 / 中国生物制品学杂志

@#Objective To investigate the effect of astragalus membranaceus（AM）injection on apoptosis and autophagy of human gastric epithelial cell line（GES⁃1）induced by enterovirus 71（EV71）. Methods GES⁃1 cells were cultured in vitro and divided into infected group（EV71 infected at a MOI of 3 and control group（no virus infected）. The morpho⁃logical changes of EV71 infected cells were observed by inverted microscope. The level of VP1 in GES⁃1 cells infected with EV71 was detected by Western blot；CCK⁃8 assay was used to detect the viability of GES⁃1 cells infected with EV71；Nuclear staining with DAPI was used to observe the morphological changes of nuclear apoptosis infected with EV71. GES⁃1 cells were divided into control group（without virus infection），infection group and AM intervention group with final concentration of 1，2. 5，5 and 10 μg／mL，respectively. Western blot was used to detect the effect of AM intervention on the expression of apoptosis⁃related proteins Caspase⁃3，PARP and autophagy⁃related proteins LC3 and P62 in GES⁃1 cells infected withEV71. CCK⁃8 method was used to detect the effect of AM intervention on the viability of GES⁃1 cells infected with EV71. Results GES⁃1 cells were round，shrunken with nuclear pyknosis and uneven size；VP1 level increased（t = 41. 56，P < 0. 01），cell viability decreased（t = 19. 07，P < 0. 01），Caspase⁃3 and PARP proteins were cut off（t = 35. 29 and 3. 648， P < 0. 01 and 0. 021 8，respectively），LC3Ⅱ／LC3Ⅰ ratio increased（t = 10. 16，P = 0. 000 5）and P62 protein was degraded（t = 68. 68，P < 0. 01）；AM inhibited the degradation of Caspase⁃3，PARP and P62 proteins induced by EV71 （t = 52. 66，59. 60 and 40. 22，respectively，each P < 0. 01）and increased the ratio of LC3Ⅱ／LC3Ⅰ（t = 5. 521，P = 0. 005 3），andreducedtheinhibitoryeffectofEV71ontheviabilityofGES⁃1cells（t =4. 420，P =0. 0115）. Conclusion EV71 infection induced apoptosis of GES⁃ 1 cells and AM intervention inhibited EV71 induced apoptosis by inhibiting EV71 induced autophagy.