ABSTRACT
Objective To study the adsorption performance of chitosan in printing and dyeing wastewater treatment.Methods The influence factors such as chitosan concentrations(0-500 mg/L),pH value(1-13),temperatures(20-50 ℃)and time(0.5-2.5 h) were considered in the test.Results When the concentration of chitosan was 200 mg/L,pH value was 2-5,time was 0.5 h and at the room temperature,the absorption could show a good result.The deeolorizing rate could reach above 90%.Conclusion The chitosan concentrations,pH value,time and temperature affect the adsorption performance of chitosan in printing and dyeing wastewater treatment.
ABSTRACT
Culture environment is the key factor in the construction of dermal skin.It was investigated that the effects of the culture methods,including the static culture and spinner flask culture,and stir speeds on the cells proliferation,metabolism and distribution within collagenchitosan sponges.A higher cell density and specific growth rate was obtained with spinner flask culture versus static culture,especially,the 80 r/min spinner flask culture.The cell distribution in dermal substitutes from stirred culture system was more uniform than static culture,as well as that with increase of stir speeds in spinner flask.In summary,the spinner flasks culture with proper stir speed shows promise for the construction of dermal substitutes in vitro.
ABSTRACT
Cell seeding of three-dimensional scaffolds is the first step of the cultivation of engineered tissues. The cell seeding density and spatial distribution in a 3-D scaffold are critical to the morphogenetic development of an engineered tissue. In the present work, human fibroblasts were seeded to collagen-chitosan sponges by static seeding, stirred seeding and perfusion seeding. The effects of seeding conditions on the resulting seeding density, the seeding efficiency and the initial cell distribution were studied. The seeding efficiency was relatively high (88.9%) at low inoculation cell density, and decreased rapidly wjth the increasing of inoculation cell density in static seeding. Stirred seeding yielded the lowest seeding efficiency. Nonuniform initial cell distribution was observed in both static and stirred seeding. The perfusion seeding, which has a characteristic of high seeding efficiency (>77%) , high initial cell density and uniform initial cell distribution in 3-D scaffolds, is the optimum method for cell seeding to 3-D scaffold.
Subject(s)
Humans , Cell Aggregation , Cell Count , Methods , Cell Culture Techniques , Methods , Cells, Cultured , Chitosan , Chemistry , Collagen , Chemistry , Fibroblasts , Cell Biology , Skin , Cell Biology , Tissue Engineering , Methods , Tissue ScaffoldsABSTRACT
Clinical evidence of hematopoietic restoration with umbilical cord blood (UCB) grafts indicates the UCB can be a useful source of hematopoietic stem cells for routine bone marrow reconstitution. Considering (10 +/- 5) x 10(8) nucleared cells per cord blood unit, there is a potential limitation for the use of cord blood in adults, which, however, can be overcome by ex vivo expansion of cells. A prerequisite for expansion is the significantly higher recovery of MNC, CD34+ cells and colony-forming cells (CFC) by thawing cryopreserved MNC. Cooling rate always acts as a critical factor that can affect the recovery of cells. Although the rate of - 1 degrees C/min is adopted in most of the cryopreservations, no data has been reported about the detailed effects of different cooling rates. The aim of the study was to reveal the different effects of cooling rates on cryopreservation of hematopoietic stem cells from cord blood. UCB samples were collected, and cryopreserved as mononuclear cells (MNC) with different cooling rates of - 0.5 degrees C/min, - 1 degrees C/min, - 5 degrees C/min, and the recovery and viability of MNC and CD34+ cells, the clonogenic capacity and the ex vivo expansion potential of UCB progenitor cells were evaluated after thawing. With - 1 degrees C/min cooling rate, the recovery of MNC reached 93.3% +/- 1.8% , viability 95.0% +/- 3.9% , recovery of CD34+ cells 80.0% +/- 17.9% , and clonogenic recovery were 87.1% +/- 5.5%, 88.5% +/- 8.9%, 86.2% +/- 7.4% for BFU-E CFU-GM CFU-MK, respectively. After 14 days of liquid culture, no significant difference was detected in CFC expansion between fresh and cryopreserved MNC cells with - 1 degrees C/min cooling rate, but this was not the case with - 0.5 degreesC/min and - 5 degrees C/min. In conclusion, it was demonstrated that controlling the rate at - 1 degrees C/min is more suitable for cryopreservation of hematopoietic stem cells than - 0.5 degrees C/min and - 5 degrees C/min.