• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.141-144
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• 2000

Highly open porous polymer matrices are required for high density cell seeding, efficient nutrient, and oxygen supply to the cells cultured in the three dimensional matrices. However, there are severe problems of mass transfer limitations within the cell/scaffolds culture system. Thus we hypothesize that continuos-flow culture conditioning of cells with the scaffolds may improve the cell viability and the differentiated function. In this study, we fabricated porous PLGA scaffolds by using gas-foaming/salt-leaching method as previous described. Viscous PLGA gel paste contains ammonium bicarbonate particulates, acting as a gas-foaming agent as well as a salt-leaching porogen, were cast into Teflon mold and dried. Ammonium bicarbonate salt upon contact to an acidic aqueous solution evloves gaseous ammonia and carbon dioxide by itself. And we conjugated galactose moiety [AGA; $N-(aminobuty1)-O-{\beta}-D-galactopyranosyl-(1{\rightarrow}4)-D-glucoamide]$ to the terminal end group of a PLGA to increase the cell adhesion and matain the differentiated function of hepatocytes. Cell-seeded scaffolds were secured in a flow bioreactor chamber and exposed to continuous flow at 5 ml/min. As a result of our study, the high yield of hepatocytes attachment was accomplished by increasing the concentration of PLGA-AGA conjugate in polymer scaffolds and cells in the scaffolds under continuos flow condition maintained a high level of viability and albumin secretion rate of cultured hepatocytes showed a higher level that of control groups.

• Molecules and Cells
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• v.40 no.2
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• pp.117-122
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• 2017

Despite the fact that porcine embryonic stem cells (ESCs) are a practical study tool, in vitro long-term maintenance of these cells is difficult in a two-dimensional (2D) microenvironment using cellular niche or extracellular matrix proteins. However, a three-dimensional (3D) microenvironment, similar to that enclosing the inner cell mass of the blastocyst, may improve in vitro maintenance of self-renewal. Accordingly, as a first step toward constructing a 3D microenvironment optimized to maintain porcine ESC self-renewal, we investigated different culture dimensions for porcine ICM-derived cells to enhance the maintenance of self-renewal. Porcine ICM-derived cells were cultured in agarose-based 3D hydrogel with self-renewal-friendly mechanics and in 2D culture plates with or without feeder cells. Subsequently, the effects of the 3D microenvironment on maintenance of self-renewal were identified by analyzing colony formation and morphology, alkaline phosphatase (AP) activity, and transcriptional and translational regulation of self-renewal-related genes. The 3D microenvironment using a 1.5% (w/v) agarose-based 3D hydrogel resulted in significantly more colonies with stereoscopic morphology, significantly improved AP activity, and increased protein expression of self-renewal-related genes compared to those in the 2D microenvironment. These results demonstrate that self-renewal of porcine ICM-derived cells can be maintained more effectively in a 3D microenvironment than in a 2D microenvironment. These results will help develop novel culture systems for ICM-derived cells derived from diverse species, which will contribute to stimulating basic and applicable studies related to ESCs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.551-558
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• 2017

To study and validate tissue-specific promoters and vectors, it is important to develop cell culture systems that retain the tissue and species specificity. Such systems are attractive alternatives to transgenic animal models. This study established a line of porcine mammary gland epithelial cells (PMECs) from a primary culture based on the cellular morphology and mRNA levels of porcine beta-casein (CSN2). The selected PMECs were stained with the cytokeratin antibody, and were shown to express milk protein genes (CSN2, lactoferrin, and whey acidic protein). In addition, to confirm the acini structure of PMEC932-7 in 3D culture, live cells were stained with SYTO-13 dye, which binds to nucleic acid. The acini of these PMECs on matrigel were formed by the aggregation of peripheral cells and featured a hollow lumens. The system was demonstrated by testing the effects of the culture conditions to cell culture including cell density and matrigel methods of the PMECs. These results suggest that PMECs possess the genetic and structural features of mammary epithelial cells.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.4
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• pp.160-164
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• 2004

In this study, we demonstrate for the first time a bio-inspired Cell-Microsystem to manipulate and detect living cells. Cultured retinal pigment epithelial cell line (ARPE-19) was directed to grow in a pre-defined Cell-Microsystem. The three-dimensional micropillars of 5 ${\mu}{\textrm}{m}$ in height and diameter of the Cell-Microsystem were fabricated. Inhibited DNA synthesis and transformed cell morphology were observed throughout the culture period. The demonstration of manipulating and detecting living cells by the surface topography is a new approach, and it will be very useful for the future design of cell-based biosensors and bioactuators.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.3
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• pp.137-143
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• 2009

It has been reported that mechanical stimulation takes a role in improving eel/ growth in skeletal system. Various research groups have been showed their own bioreactors which stimulate cell-seed three-dimensional scaffold. In this study, we hypothesized that the various conditions of mechanical stimulation would affect cell growth and proliferation. To prove our hypothesis, we designed a custom-made bioreactor capable of applying controlled compression to cell-encapsulated scaffolds. This device consisted of a circulation system and a compression system. Each parts of the bioreactor was fabricated using the rapid prototyping technology By using the rapid prototyping technology, we can modify and improve the bioreactor very rapidly For dynamic cell-culture, cell-encapsulated agarose gel was fabricated in 2% concentration. We performed dynamic cell-culture using this agarose gel and developed bioreactor in 3 days.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.1
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• pp.83-87
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• 1999

Since the blastocyst is broken and spreads out on a flat plastic culture dish (two dimensional culture) during in vitro development, it has been difficult to study the implantation process. It also has been difficult to analyse the interactions between endometrial epithelial and stromal cells because of the lack of a long-term in vitro model which can stimulate in vivo characteristics, as these cells eventually fail to proliferate or cease to express differentiated functions. Recently nontransformed cell lines, CUE-P and CUS-V2, derived from rat endometrial epithelium and stroma were reported. In this study, morphology of CUE-P and CUS-V2 was examined and oxytocin gene expression by CUE-P cells was demonstrated by RT-PCR. The CUE-P cells have a cuboidal morphology and CUS-V2 cells resemble fibroblast and exhibit a spindle-like morphology. In RT-PCR, same size of PCR products of oxytocin gene at hypothalamus, uterus and CUE-P cells were demonstrated. These results showed three dimensional culture system could be made by using the new cell lines.

• BMB Reports
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• v.56 no.1
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• pp.24-31
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• 2023

Urological cancers such as kidney, bladder, prostate, and testicular cancers are the most common types of cancers worldwide with high mortality and morbidity. To date, traditional cell lines and animal models have been broadly used to study pre-clinical applications and underlying molecular mechanisms of urological cancers. However, they cannot reflect biological phenotypes of real tissues and clinical diversities of urological cancers in vitro system. In vitro models cannot be utilized to reflect the tumor microenvironment or heterogeneity. Cancer organoids in three-dimensional culture have emerged as a promising platform for simulating tumor microenvironment and revealing heterogeneity. In this review, we summarize recent advances in prostate and kidney cancer organoids regarding culture conditions, advantages, and applications of these cancer organoids.

• BMB Reports
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• v.45 no.3
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• pp.189-193
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• 2012

Cyst formation is a major characteristic of ADPKD and is caused by the abnormal proliferation of epithelial cells. Renal cyst formation disrupts renal function and induces diverse complications. The mechanism of cyst formation is unclear. mIMCD-3 cells were established to develop simple epithelial cell cysts in 3-D culture. We confirmed previously that Mxi1 plays a role in cyst formation in Mxi1-deficient mice. Cysts in Mxi1 transfectanted cells were showed by collagen or mebiol gels in 3-D cell culture system. Causative genes of ADPKD were measured by q RT-PCR. Herein, Mxi1 transfectants rarely formed a simple epithelial cyst and induced cell death. Overexpression of Mxi1 resulted in a decrease in the PKD1, PKD2 and c-myc mRNA relating to the pathway of cyst formation. These data indicate that Mxi1 influences cyst formation of mIMCD-3 cells in 3-D culture and that Mxi1 may control the mechanism of renal cyst formation.

• Molecules and Cells
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• v.42 no.9
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• pp.617-627
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• 2019

Brain organoids are an exciting new technology with the potential to significantly change our understanding of the development and disorders of the human brain. With step-by-step differentiation protocols, three-dimensional neural tissues are self-organized from pluripotent stem cells, and recapitulate the major millstones of human brain development in vitro. Recent studies have shown that brain organoids can mimic the spatiotemporal dynamicity of neurogenesis, the formation of regional neural circuitry, and the integration of glial cells into a neural network. This suggests that brain organoids could serve as a representative model system to study the human brain. In this review, we will overview the development of brain organoid technology, its current progress and applications, and future prospects of this technology.

• Biomolecules & Therapeutics
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• v.24 no.3
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• pp.260-267
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• 2016

Mesenchymal stem cells (MSCs) offer significant therapeutic promise for various regenerative therapies. However, MSC-based therapy for injury exhibits low efficacy due to the pathological environment in target tissues and the differences between in vitro and in vivo conditions. To address this issue, we developed adipose-derived MSC spheroids as a novel delivery method to preserve the stem cell microenvironment. MSC spheroids were generated by suspension culture for 3 days, and their sizes increased in a time-dependent manner. After re-attachment of MSC spheroids to the plastic dish, their adhesion capacity and morphology were not altered. MSC spheroids showed enhanced production of hypoxia-induced angiogenic cytokines such as vascular endothelial growth factor (VEGF), stromal cell derived factor (SDF), and hepatocyte growth factor (HGF). In addition, spheroid culture promoted the preservation of extracellular matrix (ECM) components, such as laminin and fibronectin, in a culture time- and spheroid size-dependent manner. Furthermore, phosphorylation of AKT, a cell survival signal, was significantly higher and the expression of pro-apoptotic molecules, poly (ADP ribose) polymerase-1 (PARP-1) and cleaved caspase-3, was markedly lower in the spheroids than in MSCs in monolayers. In the murine hindlimb ischemia model, transplanted MSC spheroids showed better proliferation than MSCs in monolayer. These findings suggest that MSC spheroids promote MSC bioactivities via secretion of angiogenic cytokines, preservation of ECM components, and regulation of apoptotic signals. Therefore, MSC spheroid-based cell therapy may serve as a simple and effective strategy for regenerative medicine.