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Song K.,Dalian University of Technology | Yin Y.,Dalian University of Technology | Lv C.,Dalian University of Technology | Liu T.,Dalian University of Technology | And 5 more authors.
Asia-Pacific Journal of Chemical Engineering | Year: 2011

The feasibility of co-culturing hematopoietic stem/progenitor cells (HSPCs) and mesenchymal stem cells (MSCs) derived from human umbilical cord blood (UCB) using cytodex-3 microcarriers was investigated in this paper in order to assess this as a possibility for future clinical therapies. Considering the safety requirements of clinical applications, we have tried to use human autologous serum (HAS), collected from UCB, to replace the widely used fetal bovine serum (FBS). Moreover, both UCB-hematopoietic stem cells (HSCs) and UCB-MSCs could be harvested simultaneously after their ex vivo culture. In addition, the two different types of stem cells could be easily separated by sedimentation after the co-culture due to the distinct weight differences between cytodex-3 microcarriers (containing adherent MSCs) and the suspended HSCs. To optimize the culture conditions, we have assessed the effect of the concentration of HAS (2.8, 5.6, 8.3 and 11.1%) on the expansion of UCB-MSCs and UCB-HSCs. The results have indicated that the expansion of UCB-HSCs supplied with 5.6% autoserum was at least (1.88 ± 0.33)-fold, better than in the other groups, while it had no to little effect on the expansion of UCB-MSCs. We hence conclude that the optimal concentration of HAS for the co-culture conditions herein reported is 5.6%. Finally, the co-culture system we have developed and herein report is feasible to provide expanded UCB-HSPCs and UCB-MSCs for clinical applications, especially the former. © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.

Song K.,Dalian University of Technology | Liu Y.,Dalian University of Technology | MacEdo H.M.,Biological Systems Engineering Laboratory | Jiang L.,Dalian University of Technology | And 3 more authors.
Materials Science and Engineering C | Year: 2013

Nutrient depletion within three-dimensional (3D) scaffolds is one of the major hurdles in the use of this technology to grow cells for applications in tissue engineering. In order to help in addressing it, we herein propose to use the controlled release of encapsulated nutrients within polymer microspheres into chitosan-based 3D scaffolds, wherein the microspheres are embedded. This method has allowed maintaining a stable concentration of nutrients within the scaffolds over the long term. The polymer microspheres were prepared using multiple emulsions (w/o/w), in which bovine serum albumin (BSA) and poly (lactic-co-glycolic) acid (PLGA) were regarded as the protein pattern and the exoperidium material, respectively. These were then mixed with a chitosan solution in order to form the scaffolds by cryo-desiccation. The release of BSA, entrapped within the embedded microspheres, was monitored with time using a BCA kit. The morphology and structure of the PLGA microspheres containing BSA before and after embedding within the scaffold were observed under a scanning electron microscope (SEM). These had a round shape with diameters in the range of 27-55 μm, whereas the chitosan-based scaffolds had a uniform porous structure with the microspheres uniformly dispersed within their 3D structure and without any morphological change. In addition, the porosity, water absorption and degradation rate at 37 C in an aqueous environment of 1% chitosan-based scaffolds were (92.99 ± 2.51) %, (89.66 ± 0.66) % and (73.77 ± 3.21) %, respectively. The studies of BSA release from the embedded microspheres have shown a sustained and cumulative tendency with little initial burst, with (20.24 ± 0.83) % of the initial amount released after 168 h (an average rate of 0.12%/h). The protein concentration within the chitosan-based scaffolds after 168 h was found to be (11.44 ± 1.81) × 10- 2 mg/mL. This novel chitosan-based scaffold embedded with PLGA microspheres has proven to be a promising technique for the development of new and improved tissue engineering scaffolds. © 2012 Elsevier B.V. All Rights Reserved.

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