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In this study, a novel nanoparticle system for paracellular transport was prepared using a simple and mild ionic-gelation method upon addition of a poly-gamma-glutamic acid (gamma-PGA) solution into a low-molecular-weight chitosan (low-MW CS) solution. The particle size and the zeta potential value of the prepared nanoparticles can be controlled by their constituted compositions. The results obtained by the TEM and AFM examinations showed that the morphology of the prepared nanoparticles was spherical in shape. Evaluation of the prepared nanoparticles in enhancing intestinal paracellular transport was investigated in vitro in Caco-2 cell monolayers. It was found that the nanoparticles with CS dominated on the surfaces could effectively reduce the transepithelial electrical resistance (TEER) of Caco-2 cell monolayers. After removal of the incubated nanoparticles, a gradual increase in TEER was noticed. The confocal laser scanning microscopy observations confirmed that the nanoparticles with CS dominated on the surface were able to open the tight junctions between Caco-2 cells and allowed transport of the nanoparticles via the paracellular pathways.

The aforementioned results indicated that like bFGF, ginsenoside Re-associated induction of angiogenesis enhanced tissue regeneration, supporting the concept of therapeutic angiogenesis in tissue-engineering strategies.

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The results provided evidence of tissue regeneration within a porous bovine pericardium through a process involving cell recruitment and tissue-specific differentiation.

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In this study, the effects of ginsenoside Rg1, a natural compound isolated from Panax ginseng, on human umbilical vein endothelial cell (HUVEC) behavior in vitro, and on angiogenesis and tissue regeneration in genipin-fixed acellular tissue (extracellular matrix, ECM) in vivo, were investigated. Basic fibroblast growth factor (bFGF) was used as a control. The in vitro results indicated that in the presence of bFGF or Rg1, HUVEC proliferation was significantly increased. Both bFGF and Rg1 promoted HUVEC migration in a Transwell plate assay. In addition, bFGF or Rg1 significantly increased the formation of capillary-like network by HUVECs on Matrigel. Thus, both bFGF and Rg1 enhanced multiple components of angiogenic activity in vitro. The in vivo results obtained 1 week postoperatively showed that the extent of angiogenesis in ECMs was significantly enhanced by bFGF or Rg1. At 1 month postoperatively, vascularized neoconnective tissues were found to fill the pores within ECMs loaded with bFGF or Rg1. There was a significant increase in neocapillary density from 1 week to 1 month for ECMs loaded with Rg1, whereas that observed in ECMs loaded with bFGF stayed approximately the same because of the limitations of protein stability. These results suggested that Rg1 may be a new class of angiogenic agent and may be loaded in ECMs to accelerate tissue regeneration.