• BMB Reports
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• v.49 no.12
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• pp.655-661
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• 2016

Polymer brush is a soft material unit tethered covalently on the surface of scaffolds. It can induce functional and structural modification of a substrate's properties. Such surface coating approach has attracted special attentions in the fields of stem cell biology, tissue engineering, and regenerative medicine due to facile fabrication, usability of various polymers, extracellular matrix (ECM)-like structural features, and in vivo stability. Here, we summarized polymer brush-based grafting approaches comparing self-assembled monolayer (SAM)-based coating method, in addition to physico-chemical characterization techniques for surfaces such as wettability, stiffness/elasticity, roughness, and chemical composition that can affect cell adhesion, differentiation, and proliferation. We also reviewed recent advancements in cell biological applications of polymer brushes by focusing on stem cell differentiation and 3D supports/implants for tissue formation. Understanding cell behaviors on polymer brushes in the scale of nanometer length can contribute to systematic understandings of cellular responses at the interface of polymers and scaffolds and their simultaneous effects on cell behaviors for promising platform designs.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.567-569
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• 1992

Design sensitivity analysis is proposed for the optimal shape design of three dimensional magnetostatic problems. The direct differentiation method is introduced for design sensitivity analysis and the boundary element method with reduced magnetic scalar potential as the state variable is used to analyze the magnetic characteristics. In the direct differentiation method, the design sensitivity, defined as the total derivative of the objective function with respect to the design variables, is calculated based on the variation of the state variable with respect to the design variable. And the variation of He state variable is calculated by differentiating the both sides of the system matrix equation obtained by applying boundary element method. Through the numerical example with simple electromagnet, the usefullness is proved.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.29 no.2 s.43
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• pp.105-130
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• 2003

Human skin equivalents, also designated as cultured skin substitute (Boyce and Warden, 2002) or organotypic co-cultures (Maas-Szabowski et al., 1999, 2000, 2003), are three-dimensional systems that are engineered by seeding fibroblasts into a three-dimensional dermal matrix. Such a dermal equivalent is then subsequently seeded with human keratinocytes. After cell attachment, the culture is kept first under submerged condition to allow keratinocyte proliferation. Thereafter, the culture is lifted the air-liquid interface (A/L) to expose the epidermal compartment to the air, and to further induce keratinocyte differentiation. During the air-exposure, nutrients from the medium will diffuse through the underlying dermal substrate towards the epidermal compartment and support keratinocyte proliferation and differentiation. Under these conditions, a HSE is formed that shows high similarity with the native tissue from which it was derived (Figure 1) (Bell et at., 1981; Boyce et al., 1988; Ponec et al., 1997;El Ghalbzouri et al.., 2002).

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.8
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• pp.850-857
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• 1992

Design sensitivity analysis is proposed for the optimal shape design of three-dimensional magnetostatic problems. The direct differentiation method is introduced for design sensitivity analysis and the boundary element method with reduced magnetic scalar potential as the state variable is used to analyze the magnetic characteristics. In the direct differentiation method, the design sensitivity, defined as the total derivative of the objective function with respect to the design variables, is calculated based on the variation of the state variable with respect to the design variable. And the variation of the state variable is calculated by differetiating the both sides of the system matrix equation obtained by applying boundary element method. Through the numerical example with simple electromagnet, the usefulness is proved.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.3
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• pp.197-206
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• 2021

Carnosol is a phenolic diterpene phytochemical found in rosemary and sage with reported anti-microbial, anti-oxidant, anti-inflammatory, and anti-carcinogenic activities. This study aimed to investigate the effect of carnosol on the lineage commitment of mouse bone marrow-derived mesenchymal stem cells (mBMSCs) into osteoblasts and adipocytes. Interestingly, carnosol stimulated the early commitment of mBMSCs into osteoblasts in dose-dependent manner as demonstrated by increased levels of alkaline phosphatase activity and Alizarin red staining for matrix mineralization. On the other hand, carnosol significantly suppressed adipogenesis of mBMSCs and downregulated both early and late markers of adipogenesis. Carnosol showed to induce osteogenesis in a mechanism mediated by activating BMP signaling pathway and subsequently upregulating the expression of BMPs downstream osteogenic target genes. In this context, treatment of mBMSCs with LDN-193189, BMPR1 selective inhibitor showed to abolish the stimulatory effect of carnosol on BMP2-induced osteogenesis. In conclusion, our data identified carnosol as a novel osteoanabolic phytochemical that can promote the differentiation of mBMSCs into osteoblasts versus adipocytes by activating BMP-signaling.

• Journal of Periodontal and Implant Science
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• v.53 no.6
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• pp.467-477
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• 2023

Purpose: The purpose of this study was to evaluate the regenerative capacity of stem cells combined with bone graft material and a collagen matrix in rabbit calvarial defect models according to the type and form of the scaffolds, which included type I collagen matrix and synthetic bone. Methods: Mesenchymal stem cells (MSCs) were obtained from the periosteum of participants. Four symmetrical 6-mm-diameter circular defects were made in New Zealand white rabbits using a trephine drill. The defects were grafted with (1) group 1: synthetic bone (β-tricalcium phosphate/hydroxyapatite [β-TCP/HA]) and 1×10⁵ MSCs; (2) group 2: collagen matrix and 1×10⁵ MSCs; (3) group 3: β-TCP/HA, collagen matrix covering β-TCP/HA, and 1×10⁵ MSCs; or (4) group 4: β-TCP/HA, chipped collagen matrix mixed with β-TCP/HA, and 1×10⁵ MSCs. Cellular viability and cell migration rates were analyzed. Results: Uneventful healing was achieved in all areas where the defects were made at 4 weeks, and no signs of infection were identified during the healing period or at the time of retrieval. New bone formation was more evident in groups 3 and 4 than in the other groups. A densitometric analysis of the calvarium at 8 weeks post-surgery showed the highest values in group 3. Conclusions: This study showed that the highest regeneration was found when the stem cells were applied to synthetic bone along with a collagen matrix.

• Journal of Gastric Cancer
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• v.2 no.3
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• pp.151-156
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• 2002

Purpose: The prognosis of gastric cancer depends on the depth of invasion, lymph-node metastasis, invasion to adjacent tissues, and distant metastasis. Recently, it is known that tumor-associated proteases and adhesion molecules have been shown to play a relevant role in the process of progression and metastasis. The purpose of our study was to demonstrate the value of MMP-2 (matrix metalloproteinase), cathepsin D and E-cadherin as prognostic factors. Materials and Methods: In this study, formalin-fixed, paraffin-embedded tissue blocks from 69 patients with gastric cancer were immunohistochemically studied using antibodies to MMP-2, cathepsin D, and E-cadherin, and their expressions were analyzed according to the pathologic stage, lymph-node metastasis, histological differentiation, and patient survival. The medical records of these patients were retrospectively reviewed. Results: Increased expression of MMP-2 significantly correlated with advanced pathologic stage (P=0.026). Patients with lymph-node metastasis also had increased expression of MMP-2. Those patients with increased expression of MMP-2 showed a poorer survival; nevertheless, it was not statistically significant. Increased expression of cathepsin D significantly correlated with advanced pathologic stage (p=0.029). However, no correlation was observed between advanced pathologic stage and either lymph-node status or histological differentiation. Patients with increased expression of cathepsin D had a poorer survival, but that result was not statistically significant. No association was found between reduced expression of E-cadherin and pathologic stage, lymph-node status, or histological differentiation. Also, no correlation was found between the expression of E-cadherin and survival. In addition, when a combination of MMP-2 and cathepsin D expressions was analyzed, if both were negative, the survival seems to be longer, but it was not statistically significant. Conclusions: In patients with gastric cancer, expressions of MMP-2 and cathepsin D correlated with tumor stage; therefore, they may be considered as prognostic factors.

• Journal of Acupuncture Research
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• v.23 no.5
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• pp.69-77
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• 2006

Background : Mesenchymal stem cells (MSCs) are present in most of the tissue matrix, taking part in their regeneration when injury or damage occurs. The aim of this study was to investigate the presence of cells with pluripotential characteristics in human subchondral bone and the capacity of these cells to differentiate to osteoblast. Methods : Human subchondral bone were digested with collagenase. Isolated cells were cultured with a-MEM, 15% FBS, 10-8M dexamethasone and 50 ng/mL ascoric acid. Cells from 0 day(isolated cells), 7 day (first subculture) and 14 days (third subculture) were used to carry out phenotypic characterization experiments flowcytometry analysis with 11 monoclonal antibodies) and osteogenic differentiation experiments. Osteogenic differentiation of cells was assessment by quantification of bone extracellular matrix components by following analysis: alkaline phosphatase(ALP) stains to detect ALP activity, RT-PCR and western blot to detect osteocalcin (OCN), osteopontin (OPN) and type I collagen(Col I), and Alizarin red stains to detect calcium deposition. Results : Flowcytometry analyses showed that in our population more than 98% of cells were positive for MSC markers: SH-2(CD105, 99%), CD29 (95%), CD73 (95%). Cells were negative for hematopoietic markers (CD11b, CD34, and CD45). Furthermore, cells showed positive stain to multipotent markers such as CDl17 (c-kit) (15.1%), and CD166 (74.9%), and cell adhesion molecules such as CD54 (78.1%) and CD106 (63.5%). The osteogenic specific marker analyses showed that the culture of these cells for 7 and 14 days stimulates ALP, OCN, OPN and Col I synthesis by RT-PCR and Western blot analysis. Also, after 14 days in the culture of MSCs induces mineralization by Arizarin red stain. Conclusion : In this work, we demonstrated a new and efficient method for osteoblastic differentiation of human subchondral bone stem cells. As MSCs takes part in reparative processes of adult tissues, these cells could play an important role in osteogenesis.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.372-377
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• 2005

Aralia elata is an edible mountain vegetable. Angiogenesis, the formation of new blood vessels, is a process involving migration, proliferation and cell differentiation, as well as the formation of new capillary structures. Matrix metalloproteinases (MMPs) plays an important role in angiogenesis. The development of a functional vascular system requires a variety of growth factors, their receptors, and intracellular signals. This study examines the effects of water extracts from: (i) A. elata root bark (Aralia extracts); (ii) a combination of Aralia extracts and fibroblast growth factors (FGF-2) on cultured porcine coronary artery endothelial cells (PCAECs). Aralia extracts induced the migration of PCAECs, which was inhibited by MMPs inhibitors. Combining Aralia extracts and FGF-2 enhanced the migration and the secretion of MMP-2 and MMP­9 from PCAECs. We postulated that the Aralia extracts, which induced migrating activity in PCAECs, may be accomplished by increased secretion levels of MMP-2 and MMP-9.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.5
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• pp.311-325
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• 2001

Tissue engineering scaffolds play a critical role in regulating the reconstructed human tissue development. Various types of scaffolds have been developed in recent years, including fibrous matrix and foam-like scaffolds. The design of scaffold materials has been investigated extensively. However, the design of physical structure of the scaffold, especially fibrous matrices, has not received much attention. This paper compares the different characteristics of fibrous and foam-like scaffolds, and reviews regulatory roles of important scaffold properties, including surface geometry, scaffold configuration, pore structure, mechanical property and bioactivity. Tissue regeneration, cell organization, proliferation and differentiation under different microstructures were evaluated. The importance of proper scaffold selection and design is further discussed with the examples of bone tissue engineering and stem cell tissue engineering. This review addresses the importance of scaffold microstructure and provides insights in designing appropriate scaffold structure for different applications of tissue engineering.