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ABSTRACT: Microencapsulation is one of the promising strategies to develop a three-dimensional in vivo tumour-mimic model in cancer research. Although previous studies have shown that tumour cells grow well during the microencapsulated culture, it is still not clear whether the electrostatic encapsulation process has an important effect on cellular characteristics. In this study, we investigated cellular response against non-physiological stress factors existing in the electrostatic microencapsulation process, such as the high-voltage electrostatic field, suspension and nutrition-free status. Our results showed that these non-physiological stress factors did not significantly induce cellular apoptosis, and did not affect cellular adhesion and viability. Furthermore, no change was found about invasion and drug resistance of the tumour cells. The normal endoplasmic reticulum function might play a role in maintaining biological properties during the electrostatic microencapsulation process.
Journal of Microencapsulation 03/2013; · 1.55 Impact Factor
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Ying Ma, Ying Zhang,
Yang Liu,
Li Chen,
Shen Li,
Wei Zhao,
Guangwei Sun,
Na Li,
Yu Wang,
Xin Guo,
Guojun Lv,
Xiaojun Ma
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ABSTRACT: Cell microencapsulation is a promising approach for cell implantation, cell-based gene therapy, and large-scale cell culture. The well-studied α-AP (alginate-α-poly-L-lysine) microcapsules have been restricted to large-scale cell-culture and clinical applications because of high costs and cytotoxic effects in some cases. This study used ϵ-poly-L-lysine (ϵ-PLL), a high-biocompatible and low-cost food additives produced by fermentation, to prepare ϵ-AP (alginate-ϵ-PLL) microcapsules with various thickness membranes and swelling behaviors. ϵ-AP microcapsules were permeable to BSA, a standard protein of culture medium. ϵ-AP-microencapsulated Chinese hamster ovary (CHO) cells proliferated with culture time; no obvious difference with α-AP-microencapsulated CHO cells during the early 19 days. Whereas ϵ-AP-microencapsulated CHO cells kept higher viability (OD = 0.646 ± 0.012) on the 22nd day and microcapsule strength (integrity rate of 88%) on the 24th day than that of α-AP microcapsules (OD = 0.558 ± 0.025, integrity rate of 80%). ϵ-AP (alginate-ϵ-PLL) microcapsules exhibited more superior properties and could lower the costs to broaden the applications of microencapsulation technology. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Journal of Biomedical Materials Research Part A 10/2012; · 2.63 Impact Factor
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ABSTRACT: Cell microencapsulation is one of the promising strategies for in vitro production of proteins or in vivo delivery of therapeutic products. Membrane thickness controls microcapsule strength and permeability, which may in return affect cell growth and metabolism. In this study, the strength, permeability, and encapsulated Chinese hamster ovary cell proliferation and metabolism of four groups of microcapsules with different membrane thicknesses were investigated. It was found that increasing membrane thickness increases microcapsule strength, whereas decreases membrane permeability. During the first 6 days, cells within microcapsules with 10 μm thickness membrane proliferated fast and could reach a cell density of 1.9 × 10(7) cells/mL microcapsule with 92% cell density. A cell density of 5.5 × 10(7) cells/mL microcapsule with >85% cell density was achieved within microcapsules with 15 μm membrane thickness and these microcapsules kept over 88% integrity ratio after 11 days, which was much higher than that of microcapsules with 10 μm membrane thickness. Membrane with more than 20 μm thickness was not suited for encapsulated cell culture owing to low-protein diffusion rate. These results indicated that cells survived shortly within the thinnest membrane thickness. There was a specific membrane thickness more suitable for cell growth for a long-time culture. These findings will be useful for preparing microcapsules with the desired membrane thickness for microencapsulated cell culture dependent on various purposes. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2012.
Journal of Biomedical Materials Research Part A 09/2012; · 2.63 Impact Factor
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Ying Ma, Ying Zhang,
Shan Zhao,
Yu Wang,
Siran Wang,
Yan Zhou,
Na Li,
Hongguo Xie,
Weiting Yu,
Yang Liu,
Wei Wang,
Xiaojun Ma
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ABSTRACT: Microencapsulation has been a promising approach for drug delivery, cell implantation, cell-based gene therapy and large-scale cell culture. To make use of microcapsules more effectively, it is important to accurately construct the microcapsule membranes with desired properties including a certain thickness, strength, and so forth. To date single factor experiments have been widely used, however, they are time-consuming to obtain the desired membrane preparation conditions. Response surface methodology (RSM) is a mathematical and statistical technique for building empirical models that gained importance for optimizing reacting conditions. In this study, three signifficant effect factors that affect alginate-based microcapsule membrane properties, including membrane thickness, swelling degree, and mechanical stability, were determined with Plackett-Burman method, and then three empirical models were built to optimize the preparation conditions of the microcapsule membranes according to the responses of these three signifficant effect factors respectively with RSM. These models can be used to predict the characteristics of microcapsules under different membrane preparation conditions, which provide a guide for optimizing the microencapsulation technology.
Journal of Biomedical Materials Research Part A 03/2012; 100(4):989-98. · 2.63 Impact Factor
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Journal of Controlled Release 11/2011; 152 Suppl 1:e124-5. · 5.73 Impact Factor
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ABSTRACT: Novel amphiphilic chitosan derivatives (glycidol-chitosan-deoxycholic acid, G-CS-DCA) were synthesized by grafting hydrophobic moieties, deoxycholic acid (DCA), and hydrophilic moieties, glycidol, with the purpose of preparing carriers for poorly soluble drugs. Based on self-assembly, G-CS-DCA can form nanoparticles with size ranging from 160 to 210 nm, and G-CS-DCA nanoparticles maintained stable structure for about 3 months when stored in PBS (pH 7.4) at room temperature. The critical aggregation concentration decreased from 0.043 mg/mL to 0.013 mg/mL with the increase of degree of substitution (DS) of DCA. Doxorubicin (DOX) could be easily encapsulated into G-CS-DCA nanoparticles and keep a sustained release manner without burst release when exposed to PBS (pH 7.4) at 37 °C. Antitumor efficacy results showed that DOX-G-CS-DCA have significant antitumor activity when MCF-7 cells were incubated with different concentration of DOX-G-CS-DCA nanoparticles. The fluorescence imaging results indicated DOX-G-CS-DCA nanoparticles could easily be uptaken by MCF-7 cells. These results suggested that G-CS-DCA nanoparticles may be a promising carrier for DOX delivery in cancer therapy.
Biomacromolecules 10/2010; 11(12):3480-6. · 5.48 Impact Factor
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ABSTRACT: Aggregating into multicellular spheroids within alginate–poly-L-lysine–alginate (APA) microcapsules is important in maintaining the cellular viability and specific functions. However, in the absence of a vascular network, cells in the core of large-sized spheroids are gradually necrotic because of oxygen transfer limitations. In this study, a novel APA microcapsule embedded with three-dimensional fibrous scaffolds (called APA-FS) was proposed to eliminate cellular necrosis by regulating cells to form multi-small spheroids. HepG2 cells were embedded within the APA-FS to form spheroids and the state of these spheroids was evaluated via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazoliumbromide assay, glucose/lactate metabolism, live/dead staining, and hematoxylin and eosin staining. Comparing with the conventional APA microcapsules, the cells within APA-FS organized into multi-small spheroids. The size of these spheroids depended on the concentration of fibrous scaffolds embedded within the microcapsules. In the APA-FS embedded with 5% (v/v) fibrous scaffolds, the average size of cellular spheroids was controlled below 100 microm and the cellular viability was increased by 50% than the control. The results of live/dead staining and hematoxylin and eosin staining showed that the improved cellular viability might be attributed to the decreased necrosis in the core of these spheroids. The improved viability of cells demonstrated the efficiency of this technology. These findings implied that this system might provide a more suitable culture environment for a variety of tissue engineering applications.
Tissue Engineering Part C Methods 10/2010; 16(5):1023-32. · 4.64 Impact Factor
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ABSTRACT: Cell microencapsulation is a promising approach for cell implantation, cell-based gene therapy and large-scale cell culture. For better quality control, it is important to accurately measure the microencapsulated cell viability and proliferation in the culture. A number of assays have been used for this purpose, but limitations arise. In this study, we investigated the feasibility and reliability of resazurin as a cell growth indicator in microencapsulated culture system. According to the experiment data, there was a reversible, time- and dose-dependent growth inhibition as observed for resazurin application in encapsulated cells. A positive relationship was observed between reduction of resazurin and CHO cell number in microcapsule. Moreover, the resazurin assay provided an equivalent result to the commonly used MTT method in determining CHO cell proliferation in APA microcapsule with no notable influence on cell distribution and organization pattern. In conclusion, resazurin assay is offered as a simple, rapid and non-invasive method for in vitro microencapsulated cell viability and proliferation measurement.
Applied biochemistry and biotechnology 05/2010; 162(7):1996-2007. · 1.94 Impact Factor
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ABSTRACT: A novel kind of chitosan derivatives (CS-LA-TM) were synthesized by grafting hydrophobic molecules of lithocholic acid (LA) and quaternization. CS-LA-TM and micelle-like self-aggregates were characterized by FTIR, 1H NMR, fluorescence spectroscopy, dynamic light scattering, and transmission electron microscopy (TEM). The critical micelles concentration (CMC) ranging from 0.009 mg/mL to 0.030 mg/mL decreased with increasing of the degree of substitution (DS) of LA, pH of medium but with decreasing of the degree of quaternization (DQ) of amino groups. The TEM images demonstrated that spherical CS-LA-TM nanoaggregates with uniform size were formed by self-assembly. The sizes (100-200 nm) of CS-LAs-TMs nanoaggregates increased with increasing of DS, DQ, and can be easily controlled by pH of medium, which may confer the nanoaggregates potential as delivery systems for anticancer drugs, or DNA and siRNA.
Journal of Nanoscience and Nanotechnology 04/2010; 10(4):2304-13. · 1.56 Impact Factor
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ABSTRACT: Background aims Umbilical cord blood (UCB) cells are an attractive choice in cytotherapy and represent an alternative to hepatocytes. The aim of this study was to investigate the feasibility of using the technique of microencapsulation to study the differentiation and function of UCB cells in an injured liver model and the potential of encapsulated UCB cells for use in the reversal of hepatic injury. Methods UCB cells were isolated from fresh human UCB, encapsulated using the alginate-poly-lysine-alginate method and transplanted intraperitoneally into liver-injured mice induced by CCl(4). Encapsulated UCB cell growth, viability and differentiation in vivo were detected. For evaluating the recovery of injured liver tissues, serum aminotransferases and liver histology were assessed. Results Encapsulated UCB cells showed better growth behavior after being implanted. Under conditions favoring differentiation in vivo, the expression of alpha-fetoprotein (AFP) and albumin (ALB) and urea synthesis were detected in a time-dependent manner. Serum aminotransferases were decreased after transplantation of encapsulated UCB cells into injured mice, and damage to the histologic structure of the liver was reduced. Conclusions The cell microencapsulation system provides a novel approach for learning more about the differentiation and function of UCB cells in vivo.Transplantation of encapsulated UCB cells can enhance recovery of CCl(4)-injured mouse liver. These observations suggest potential as an alternative to hepatocyte transplantation for cellular therapy of liver failure.
Cytotherapy 09/2009; · 3.63 Impact Factor
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ABSTRACT: Alginate/chitosan polyelectrolyte complex (PEC) hybrid fibers are promising materials for scaffold-making in tissue engineering. In this study, a new method termed "hydro-spinning" was developed to make alginate/chitosan hybrid fibers. In hydro-spinning, a chitosan solution was pumped into a flowing sodium alginate solution and sheared into streamlines. These elongated streamlines subsequently transformed into alginate/chitosan PEC ribbon-like fibers before breaking up into pieces. Average diameter and chitosan content of the fibers correlated positively with the chitosan concentration used in spinning. These hybrid fibers showed a high water-absorbability of around 50-fold to 60-fold of water to their dry weight and could retain their integrity after saturation in minimum essential medium (MEM) medium for 30 days. In vitro culture experiments demonstrated that these fibers were able to support the three-dimensional growth of MCF-7, suggesting the potential applications of these fibers in biomedical and bioengineering fields such as tissue engineering.
Journal of Biomedical Materials Research Part A 09/2009; 93(3):910-9. · 2.63 Impact Factor
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ABSTRACT: Umbilical cord blood (UCB) cells are an attractive choice in cytotherapy and represent an alternative to hepatocytes. The aim of this study was to investigate the feasibility of using the technique of micro-encapsulation to study the differentiation and function of UCB cells in an injured liver model and the potential of encapsulated UCB cells for use in the reversal of hepatic injury.
UCB cells were isolated from fresh human UCB, encapsulated using the alginate-poly-lysine-alginate method and transplanted intraperitoneally into liver-injured mice induced by CCl4. Encapsulated UCB cell growth, viability and differentiation in vivo were detected. For evaluating the recovery of injured liver tissues, serum aminotransferases and liver histology were assessed.
Encapsulated UCB cells showed better growth behavior after being implanted. Under conditions favoring differentiation in vivo, the expression of alpha-fetoprotein (AFP) and albumin (ALB) and urea synthesis were detected in a time-dependent manner. Serum amino-transferases were decreased after transplantation of encapsulated UCB cells into injured mice, and damage to the histologic structure of the liver was reduced.
The cell microencapsulation system provides a novel approach for learning more about the differentiation and function of UCB cells in vivo. Transplantation of encapsulated UCB cells can enhance recovery of CCl4-injured mouse liver. These observations suggest potential as an alternative to hepatocyte transplantation for cellular therapy of liver failure.
Cytotherapy 01/2009; 11(8):1032-40. · 3.63 Impact Factor
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ABSTRACT: Microencapsulation of recombinant cells is a novel means for gene therapy. However, one of the major concerns is the relationship between the permeability of microcapsule and cell growth. Many studies have focused on the permeability of empty microcapsule, but little is known about the effect of the cell growth on the permeability of a cell-contained microcapsule. A combination of fluorescence labeled protein and confocal laser scanning microscope (CLSM) provides the information about the permeability changes during the cell growth. A decrease of membrane permeability was detected on the 14th day. Meanwhile, membrane surface protein fouling was also investigated. A significant increase of membrane surface protein content was detected on the 21st day. In order to study the effect of the permeability changes on the cell viability, the membrane of cell-contained microcapsules with different permeability was set up by incubating gel beads in poly-L-lysine for 5 and 30 min, respectively, to mimic the bovine serum albumin cutoff, and a retard of cell growth was found in 7 days' culture. These results showed that the protein fouling of the microcapsule membrane caused by the cell growth may be an important factor to influence cell viability.
Journal of Biomedical Materials Research Part A 08/2008; 90(3):773-83. · 2.63 Impact Factor
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ABSTRACT: Microencapsulation of recombinant cells secreting endostatin offers a promising approach to tumor gene therapy in which therapeutic protein is delivered in a sustainable and long-term fashion by encapsulated recombinant cells. However, the studies of cell growth and protein production in vivo are very limited. In this study, the effects of microencapsulation parameters on in vivo cell growth, endostatin production, and microcapsule stability after implantation in the peritoneal cavity of mice were for the first time investigated. Microcapsules with liquid core reached higher cell density and endostatin production at day 18 than microcapsules with solid core. There was no significant difference in stability whether the core of the microcapsule was solid or liquid. Decrease in microcapsule size increased the stability of microcapsule. The microcapsules kept intact in the peritoneal cavity of mice after 36 days of implantation when the microcapsules size was 240 microm in diameter, which gave rise to high endostatin production as well. The optimized microencapsulation conditions for in vivo implantation are liquid core and 240 microm in diameter. This study provides useful information for antiangiogenic gene therapy to tumors using microencapsulated recombinant cells.
Journal of Biomedical Materials Research Part B Applied Biomaterials 02/2008; 84(1):79-88. · 2.15 Impact Factor
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ABSTRACT: Microencapsulation of recombinant cells is a novel alternative approach to tumor gene therapy. Therapeutic protein delivery can be sustained for systemic treatment of tumors because the recombinant cells are enclosed in microcapsules and the semipermeable membrane of the microcapsules protects the cells from host immune rejection and reduces the need for frequent injection. In this study, we describe a method to systemically inhibit tumor growth by in vivo culture of antiangiogenic endostatin-secreting Chinese hamster ovary (CHO) cells in microcapsules as small as 200 microm in diameter. Peritoneal administration of encapsulated endostatin-CHO cells inhibited melanoma growth to 66.4% and enhanced the survival of treated mice to 80% by 27 days posttreatment. Continuous systemic release of endostatin from microcapsules offers an effective therapeutic strategy to eradicate solid tumors.
Human Gene Therapy 06/2007; 18(5):474-81. · 4.22 Impact Factor
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ABSTRACT: Transplantation of the microencapsulated recombinant cells is a novel alternative approach to gene therapy of tumors. The semi-permeable membrane of microcapsule protects cells from host's immune rejection, increases the efficiency of gene transfer and reduces the need for frequent injection. Optimization of the preparation and culture is needed to acquire biological microcapsule with high cell viability and protein production. In this work, we studied the effect of different preparation and culture condition on the microencapsulated recombinant CHO cells growth and endostatin production. The result showed that the inoculum cells growth phase and seeding density potently affected the growth and endostatin production of the recombinant CHO cells in the microcapsule. The exponential growth phase recombinant CHO cells with a seeding density of 1 x 10(6) - 2 x 10(6) cells/ mL microcapsules benefited to the cells growth and endostatin production. The time of preparation was another important effect factor of cells viability, the cells viability decreased with the increase of preparation time and the time of preparation should be under 5h for maintaining the cell viability and endostain production. The highest viable cell density and endostatin production was acquired when the microcapsule percentage was 5% in the culture of the microencapsulated cells, the cell growth and endostatin production decreased with the increase of the microcapsule percentage.
Sheng wu gong cheng xue bao = Chinese journal of biotechnology 06/2007; 23(3):502-7.
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ABSTRACT: Endostatin, a C-terminal fragment of collagen 18a, inhibits the growth of established tumors and metastases in vivo by inhibiting angiogenesis. However, the purification procedures required for large-scale production and the attendant cost of these processes, together with the low effectiveness in clinical tests, suggest that alternative delivery methods might be required for efficient therapeutic use of endostatin. In the present study, we transfected Chinese hamster ovary (CHO) cells with a human endostatin gene expression vector and encapsulated the CHO cells in alginate-poly-L-lysine microcapsules. The release of biologically active endostatin was confirmed using the chicken chorioallantoic membrane assay. The encapsulated endostatin-expressing CHO cells can inhibit the growth of primary tumors in a subcutaneous B16 tumor model when injected into the abdominal cavity of mouse. These results widen the clinical application of the microencapsulated cell endostatin delivery system in cancer treatment.
Acta Biochimica et Biophysica Sinica 05/2007; 39(4):278-84. · 1.38 Impact Factor
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ABSTRACT: Microencapsulation of recombinant cells is a novel promising approach to tumor therapy in which therapeutic protein is sustainable and long-term delivered by microencapsulated cells. The semi-permeable membrane of microcapsule can protect cell from host's immune rejection, increase the chemical stability of therapeutic protein and circumvent the problems of toxicity, limited half-lives and variation in circulating levels. Endostatin, a potent and specific angiogenesis inhibitor, could suppress the growth of primary and metastatic lesions in multiple murine tumor models. In this paper, APA microcapsules with high strength kept intact over 35 days and recombinant CHO cells kept the rapid proliferation viability and the continuous endostatin-expression function. The study of tumor treatment showed that the implantation of microencapsulated recombinant CHO cells decreased the neovascularization of tumor tissue by 59.4% and inhibited the B16 melanoma growth by 77.4%. Twenty days after tumor cell injection, 80% of animals treated with microencapsulated CHO-endo cells were alive compared to only 50% of animals in either control or mock control groups. Therefore, continuous delivery of endostatin from microencapsulated recombinant cells represents a feasible approach to tumor therapy.
Annals of Biomedical Engineering 05/2007; 35(4):605-14. · 2.37 Impact Factor
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ABSTRACT: Microencapsulated recombinant cells technology is a novel approach to tumors therapy. It is necessary to prepare a plenty of the microcapsules with better cell viability and higher endostatin production in order to bring this technology into the clinic. The in vitro culture and cryopreservation are very important parameters in the preparation of microencapsulated cells. In this work, we studied the effect of the in vitro culture and cryopreservation on microencapsulated recombinant cells growth and endostatin production and the effect of the in vitro culture on the cryopreservation of microencapsulated recombinant cells. The results showed that the time of in vitro culture potently affected microencapsulated recombinant CHO cells growth in vivo, endostatin production and the microcapsule stability. The microcapsule kept intact after 36 days of implantation when the in vitro culture time was under 4 days. The thawed microencapsulated recombinant CHO cells had better cell growth and higher endostatin production after 40 days of cryopreservation when the in vitro culture time was 4 days and 8 days. Therefore, the best in vitro culture time was 4 days according to the results of the in vivo culture and cryopreservation and the cryopreservation did not affect microencapsulated recombinant CHO cells growth in vivo, endostatin production and the microcapsule stability.
Sheng wu gong cheng xue bao = Chinese journal of biotechnology 04/2007; 23(2):303-9.
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ABSTRACT: In this study, we investigated the effect of the microenvironment provided by alginate-poly-L-lysine-alginate (APA) microcapsule with liquefied or gelled core on the proliferation, viability, and metabolism of human cells, including anchorage-dependent MCF-7 breast cancer cells and primary fibroblasts, and anchorage-independent K-562 leukemia cells; cells in conventional culture were used as control. The growth pattern of cells in microcapsule was examined by phase-contrast micrography. The cell viability, proliferation, organization, and gene expression were evaluated by 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, hematoxylin and eosin staining, live/dead staining, 5-bromo-20-deoxyuridine labeling, and immunohistochemistry, respectively. Cell metabolism was determined by measuring glucose and lactate concentrations in medium. The results demonstrate that APA microcapsule with liquefied core provides a microenvironment for both anchorage-dependent and anchorage-independent cells to grow into a large cell aggregate and maintain cell viability at a constant level for a period of time. In conclusion, cells in APA microcapsule are alive and have proliferation potential with lower metabolism rate. APA microcapsule may be a useful tool for in vitro tumor cell modeling and anticancer drug screening as well as for cancer gene therapy. In addition, it lays a solid foundation for the use of microencapsulation in cell culture in vitro and cell implantation in vivo.
Applied Biochemistry and Biotechnology 08/2006; 134(1):61-76. · 1.94 Impact Factor
