Alginate,low mole mass heparin-chitosan-alginate,low mole mass heparin microcapsules(ALCAL) with good mechanical stability were made from the high voltage pulsing microcapsule shaping device.ALCAL was made of low-mole-mass heparin(LMWH),alginate(ALG)and chitosan(CS)by supramolecular layer upon layer self-assembled technique.It was found from the microscopic observation that the microcapsules had smooth surface and a porous structure with interconnected pores.The results of the permeability experiment of microcapsules using fluorescein isothiocyanate-bovine serum albumin(FITC-BSA)and fluorescein isothiocyanate-immunoglobulin G(FITC-IgG)showed that the ALCAL membrane could provide cell immuno-isolation;meanwhile,the ALCAL membrane had good biocompatibility.The potential of ALCAL microcapsules for the encapsulation of liver cells had been investigated and showed that the ALCAL membrane supports the survival,proliferation and protein secretion on encapsulating hepatocytes.The ALCAL microcapsule had several advantages compared to more widely used alginate-chitosan-alginate(ACA)microcapsules for the application of cell therapy.
BACKGROUND: The bioartificial liver (BAL) is considered a possible alternative method for treating liver failure. The core of the BAL system is culturing liver cells in vitro with high density and activity. Microcarrier culture is a mode of high-density culture. We set out to prepare a novel porous microcarrier to improve the activity of liver cells in vitro. METHODS: Chitosan was used to prepare a novel porous spherical microcarrier with interconnected structure. The chitosan porous microcarriers (CPMs) were modified with gelatin to improve their biocompatibility. CPMs were co-cultured with liver cells, HL-7702 (L-02), to evaluate their effect on cell culture. RESULTS: The average size of the CPMs was about 400 μm in diameter and their apertures were less than 30 μm. The pores of the microcarrier were interconnected. After fixation by sodium tripolyphosphate, the structure of the first freeze-dried CPMs was stable. To further improve the biocompatibility, the surface of CPMs was modified with gelatin through chemical crosslinking (GM-CPMs). Comparing the proliferation curves of L-02 cells cultured on simple CPMs, GM-CPMs and tissue culture polystyrene (TCPS, a mode of planar cell culture), the proliferation rates were similar in the first 5 days and the cells proliferated until day 8 in culture with microcarriers. The OD value of liver cells cultured on GM-CPMs was 1.97-fold higher than that on TCPS culture at day 8. Levels of urea and albumin in supernatants of cells cultured on GM-CPMs increased steadily for 8 days, and were clearly higher than those of cells cultured on TCPS (P<0.05).CONCLUSIONS: The novel CPMs were promising microcarriers for hepatocyte culture and the GM-CPM seemed better. Porous microcarrier culture was beneficial for hepatocyte function and activity.
Xu-Bo Wu, Cheng-Hong Peng, Fang Huang, Jie Kuang, Song-Lin Yu, Ya-Dong Dong and Bao-San Han Center of Organ Transplantation, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China Department of General Surgery, Central Hospital, Minhang District, Shanghai 201100, China
