The surface of polypropylene (PP) membrane was modified by low temperature plasma with ammonia. The effect of exposure time was investigated by means of contact angle measurement. The results show that low temperature...The surface of polypropylene (PP) membrane was modified by low temperature plasma with ammonia. The effect of exposure time was investigated by means of contact angle measurement. The results show that low temperature ammonia plasma treatment can enhance its hydrophilicity. Chinese hamster ovary (CHO) cells attachment on the modified membrane was enhanced and the growth rate on the membrane was faster than unmodified one.展开更多
The fructose modified chitosan microcarries (CMs) were prepared by the reaction of glutaraldehyde with fructose-modified chitosan. Various factors that influence the preparation were studied and the reaction condition...The fructose modified chitosan microcarries (CMs) were prepared by the reaction of glutaraldehyde with fructose-modified chitosan. Various factors that influence the preparation were studied and the reaction conditions were optimized. Morphology of rat hepatocytes cultured on CMs was observed using phase contrast microscope and scanning electron microscope, and the metabolic activities were measured. Rat hepatocytes cultured on CMs retained the spherical shape as they have in vivo and had high metabolic activities. Fructose can enhance the metabolic activity of hepatocytes and the modified CMs are promising scaffold for hepatocytes attachment.展开更多
Microencapsulated genetically engineered bac- teria cells are a novel approach of oral therapy for uremia. Klebsiella aerogenes urease genes (UreaDABCEFG) are transformed into E. coli DH5αcells through plasmid pKAU17...Microencapsulated genetically engineered bac- teria cells are a novel approach of oral therapy for uremia. Klebsiella aerogenes urease genes (UreaDABCEFG) are transformed into E. coli DH5αcells through plasmid pKAU17. The transformant can use urea or ammonia as its sole nitrogen source through strain training. The urease ge- netically engineered bacteria cells are entrapped in polyvinyl alcohol (PVA) microcapsules, which can be used to remove urea from uremia patients. The mechanical strength of PVA microcapsules is significantly higher than that of APA microcapsules. This suggests that the problem of friability of APA can be solved in this way. The optimal conditions for the preparation of PVA microencapsulated genetically engi- neered bacterial cells are: polyvinyl alcohol (PVA, 2450±50) used as the carrier at a concentration 6%, the pH value of boric acid as crosslinking reagent 6.5, crosslinking time 24 h, entrapment ratio of bacteria 8 %, air flow rate of the encap- sulate device 3 L/min and liquid flow rate at 1 mL/10 min. The average diameter of microcapsules prepared under these optimal conditions is 20—40 mesh. Experiments in vitro showed that one hundred milligrams of wet bacterial cells in PVA microcapsules could remove 18.4 mg of urea in 4 h.展开更多
基金The National Natural Science Foundation of China (No. 29776027)
文摘The surface of polypropylene (PP) membrane was modified by low temperature plasma with ammonia. The effect of exposure time was investigated by means of contact angle measurement. The results show that low temperature ammonia plasma treatment can enhance its hydrophilicity. Chinese hamster ovary (CHO) cells attachment on the modified membrane was enhanced and the growth rate on the membrane was faster than unmodified one.
基金The Natural Science Foundation of China (No. 30070222)
文摘The fructose modified chitosan microcarries (CMs) were prepared by the reaction of glutaraldehyde with fructose-modified chitosan. Various factors that influence the preparation were studied and the reaction conditions were optimized. Morphology of rat hepatocytes cultured on CMs was observed using phase contrast microscope and scanning electron microscope, and the metabolic activities were measured. Rat hepatocytes cultured on CMs retained the spherical shape as they have in vivo and had high metabolic activities. Fructose can enhance the metabolic activity of hepatocytes and the modified CMs are promising scaffold for hepatocytes attachment.
文摘Microencapsulated genetically engineered bac- teria cells are a novel approach of oral therapy for uremia. Klebsiella aerogenes urease genes (UreaDABCEFG) are transformed into E. coli DH5αcells through plasmid pKAU17. The transformant can use urea or ammonia as its sole nitrogen source through strain training. The urease ge- netically engineered bacteria cells are entrapped in polyvinyl alcohol (PVA) microcapsules, which can be used to remove urea from uremia patients. The mechanical strength of PVA microcapsules is significantly higher than that of APA microcapsules. This suggests that the problem of friability of APA can be solved in this way. The optimal conditions for the preparation of PVA microencapsulated genetically engi- neered bacterial cells are: polyvinyl alcohol (PVA, 2450±50) used as the carrier at a concentration 6%, the pH value of boric acid as crosslinking reagent 6.5, crosslinking time 24 h, entrapment ratio of bacteria 8 %, air flow rate of the encap- sulate device 3 L/min and liquid flow rate at 1 mL/10 min. The average diameter of microcapsules prepared under these optimal conditions is 20—40 mesh. Experiments in vitro showed that one hundred milligrams of wet bacterial cells in PVA microcapsules could remove 18.4 mg of urea in 4 h.
