Jangho Kim

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Abstract: Nanoscale topography of artificial substrates can greatly influence the fate of stem cells including adhesion, proliferation, and differentiation. Thus the design and manipulation of nanoscale stem cell culture platforms or scaffolds are of great importance as a strategy in stem cell and tissue engineering applications. In this article, we propose that a graphene oxide (GO) film is an efficient platform for modulating structure and function of human adipose-derived stem cells (hASCs). Using a self-assembly method, we successfully coated GO on glass for fabricating GO films. The hASCs grown on the GO films showed increased adhesion, indicated by a large number of focal adhesions, and higher correlation between the orientations of actin filaments and vinculin bands compared to hASCs grown on the glass (uncoated GO substrate). It was also found that the GO films showed the stronger affinity for hASCs than the glass. In addition, the GO film proved to be a suitable environment for the time-dependent viability of hASCs. The enhanced differentiation of hASCs included osteogenesis, adipogenesis, and epithelial genesis, while chondrogenic differentiation of hASCs was decreased, compared to tissue culture polystyrene as a control substrate. The data obtained here collectively demonstrates that the GO film is an efficient substratum for the adhesion, proliferation, and differentiation of hASCs.
Abstract: Nanoscale topography of artificial substrates can greatly influence the fate of stem cells including adhesion, proliferation, and differentiation. Thus the design and manipulation of nanoscale stem cell culture platforms or scaffolds are of great importance as a strategy in stem cell and tissue engineering applications. In this article, we propose that a graphene oxide (GO) film is an efficient platform for modulating structure and function of human adipose-derived stem cells (hASCs). Using a self-assembly method, we successfully coated GO on glass for fabricating GO films. The hASCs grown on the GO films showed increased adhesion, indicated by a large number of focal adhesions, and higher correlation between the orientations of actin filaments and vinculin bands compared to hASCs grown on the glass (uncoated GO substrate). It was also found that the GO films showed the stronger affinity for hASCs than the glass. In addition, the GO film proved to be a suitable environment for the time-dependent viability of hASCs. The enhanced differentiation of hASCs included osteogenesis, adipogenesis, and epithelial genesis, while chondrogenic differentiation of hASCs was decreased, compared to tissue culture polystyrene as a control substrate. The data obtained here collectively demonstrates that the GO film is an efficient substratum for the adhesion, proliferation, and differentiation of hASCs.
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'''4. Jangho Kim*, YR Kim*, H Seonwoo, KT Lim, YJ Kim, YH Choung, JH Chung. "Graphene-Incorporated Chitosan Substrata for Adhesion and Differentiation of Stem Cells." Journal of Materials Chemistry B (Communication, Accepted, *equal contribution, Selected as One of the Most Read Articles in JMC-B in January, 2013)).'''
'''4. Jangho Kim*, YR Kim*, H Seonwoo, KT Lim, YJ Kim, YH Choung, JH Chung. "Graphene-Incorporated Chitosan Substrata for Adhesion and Differentiation of Stem Cells." Journal of Materials Chemistry B (Communication, Accepted, *equal contribution, Selected as One of the Most Read Articles in JMC-B in January, 2013)).'''

Revision as of 11:00, 6 April 2013

Biosketch (March, 2013)

  • Jangho Kim, PhD Student
  • Seoul National University
  • Member, Tissue Engineering Young Investigator Council
  • Tissue Engineering Parts A, B, & C, USA
  • Bldg 200 Rm 2205, 599 Gwanangno, Gwanak-Gu
  • Seoul, 151-921, Rebublic of Korea
  • E-mail: rain2000@snu.ac.kr
  • http://biome.snu.ac.kr

Jangho Kim is a PhD graduate student at the Seoul National University (SNU) and a member of Tissue Engineering Young Investigator Council (YIC) of the Tissue Engineering journals and the Tissue Engineering and Regenerative Medicine International Society (TERMIS). Prior to joining the current position, he studied as a Research Associate of the Research Institute for Agriculture and Life Sciences and a Senior Researcher of the Biomechanics & Tissue Engineering Laboratory at the SNU. He also studied as a Research Scholar in the Thin Film & Charged Particles Research Laboratory at Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign (UIUC) from 2009 to 2010. His research interests include 1) development of biomaterial-based nano/microscale devices (e.g., nanotopography), 2) their applications for biological systems engineering including animal/human stem cell/tissue engineering and food/agriculture engineering, and 3) development of novel strategies for better understanding or engineering small biosystems (e.g., cell, tissue, and organs in animal or human). He has authored and co-authored more than 30 peer-reviewed journal publications, 45 peer reviewed conference proceedings or meeting abstracts, and 1 issued patent in the area of biological systems engineering focused on the nano/microtechnology. He received the Award for Best Poster Presentation from the KSAM 2007 Conference (Biological Engineering section) in 2007, the KSAM 2008 Conference (Biological Engineering section) in 2008, and the KSAM 2012 Conference (Biological Engineering section) in 2012, respectively. He received the Award for Outstanding Oral Presentation (outstanding research award) from the Korea Tissue Engineering and Regenerative Medicine Society in 2012. He was also selected as Excellent Researcher from the Research Institute for Agriculture and Life Sciences, SNU in December 2011. He received the National Graduate S&T Scholarship from Korea Science and Engineering Foundation during 2007-2008 and was selected as a candidate for Seoul Science Fellowship in 2008. He also received the Research Scholarship from the UIUC during 2009-2010. He has been selected the members of the very first Tissue Engineering Young Investigator Council (selected from international young researchers of over 300 qualified candidates). He also received the Young Scientist Award from the Korean Society for Biomaterials and the Japanese Society for Biomaterials in 2012. He is currently studying under guidance of Prof. Jong Hoon Chung at the SNU as a main advisor, Prof. Yun-Hoon Choung at the Ajou-SOM, and Prof. Deok-Ho Kim at the University of Washington as co-advisors as well as lots of collaborative professors and colleagues. He serves as a peer reviewer for journal publications such as Tissue Engineering, Tissue Engineering and Regenerative Medicine, Lab on a Chip, Chemical Communications, Biomacromolecules, Materials Science and Engineering C, Archives of Medical Research, Journal of Materials Chemistry, Journal of Materials Chemistry B, Integrative Biology, RSC Advances, and so on. His one of the purposes of his life is that he will be able to contribute to the real world benefits through his researches. Please contact him if you have any questions or interests to join collaborative researches with him. Thank you.

Jangho Kim (left) with his fiancee (KyoungJin Shin) at the Gyeonghoeru in Seoul.

Selected Journal Publications

1. Jangho Kim, SW Kim, S Park, KT Lim, H Swonwoo, Y Kim, BH Hong, YH Choung, JH Chung. “Bacterial Cellulose Nanofibrillar Patch as a Wound Healing Platform of Tympanic Membrane Perforation.” Advanced Healthcare Materials (Accepted).

Abstract: Bacterial cellulose (BC)-based biomaterials on medical device platforms have gained significant interest for tissue-engineered scaffolds or engraftment materials in regenerative medicine. In particular, BC has an ultrafine and highly pure nanofibril network structure and can be used as an efficient wound-healing platform since cell migration into a wound site is strongly meditated by the structural properties of the extracellular matrix. Here, we report the fabrication of a nanofibrillar patch by using BC and its application as a new wound-healing platform for traumatic tympanic membrane (TM) perforation. TM perforation is a very common clinical problem worldwide and presents as conductive healing loss and chronic perforations. The BC nanofibrillar patch can be synthesized from Gluconacetobacter xylinus; it was found that the patch contained a network of nanofibrils and was transparent. The thickness of the BC nanofibrillar patch was found to be approximately 10.33 ± 0.58 µm, and the tensile strength and Young’s modulus of the BC nanofibrillar patch were 11.85 ± 2.43 and 11.90 ± 0.48 MPa, respectively, satisfying the requirements of an ideal wound-healing platform for TM regeneration. In vitro studies involving TM cells showed that TM cell proliferation and migration were stimulated under the guidance of the BC nanofibrillar patch. In vivo animal studies demonstrated that the BC nanofibrillar patch promotes the rate of TM healing as well as aids in the recovery of TM function. Our data demonstrate that the BC nanofibrillar patch is an efficient wound-healing platform for TM perforation.

2. Jangho Kim*, DH Kim*, KT Lim, H Swonwoo, SH Park, YR Kim, YH Choung, PH Choung, JH Chung. “Charged Nanomatrices as Efficient Platforms for Modulating Cell Adhesion and Shape.” Tissue Engineering: Part C, 2012:18(12):913-923. (Selected as a Cover Article and a Featured Article).

Abstract: In this article, we describe the design and manipulation of charged nanomatrices and their application as efficient platforms for modulating cell behaviors. Using electrospraying technology and well designed biomaterials, poly(ε-caprolactone) (PCL) and polyethylenimine (PEI), the negatively charged PCL nanomatrix (nPCL nanomatrix) and the positively charged PCL nanomatrix (pPCL nanomatrix) were fabricated. It was found that cell adhesion, affinity, and shape were sensitively modulated in negatively and positively charged nanomatrices. Our results showed that the pPCL nanomatrix promoted adhesion of NIH 3T3 fibroblast cells as compared to the nPCL nanomatrix. When fluid shear stress was applied, the pPCL nanomatrix showed the stronger environment for cell affinity than the nPCL nanomatrix. NIH 3T3 fibroblast cells adopted a relatively spherical shape on the pPCL nanomatrix versus an aligned, narrow shape on the nPCL nanomatrix. It was also found that charged nanomatrices influenced the cross-sectional cell shape. The cross-sectional cell shape on the pPCL nanomatrix was extremely flattened, whereas the cross-sectional cell shape was relatively round on the nPCL nanomatrix and some of the adhered cells floated. We also showed that the surfaces of the nPCL and the pPCL nanomatrices adsorbed the different serum proteins. These results collectively demonstrated a combination of environmental factors including nanoscale structure, electrostatic forces, and absorption of biomolecules on charged substrates affected cell response in terms of cellular adhesion and shape.

3. Jangho Kim, S Choi, YJ Kim, KT Lim, H Seonwoo, Y Park, DH Kim, PH Choung, CS Cho, SY Kim, YH Choung, JH Chung. "Bioactive Effects of Graphene Oxide Cell Culture Substratum on Structure and Function of Human Adipose-Derived Stem Cells." Journal of Biomedical Materials Research: Part A (Accepted).

Abstract: Nanoscale topography of artificial substrates can greatly influence the fate of stem cells including adhesion, proliferation, and differentiation. Thus the design and manipulation of nanoscale stem cell culture platforms or scaffolds are of great importance as a strategy in stem cell and tissue engineering applications. In this article, we propose that a graphene oxide (GO) film is an efficient platform for modulating structure and function of human adipose-derived stem cells (hASCs). Using a self-assembly method, we successfully coated GO on glass for fabricating GO films. The hASCs grown on the GO films showed increased adhesion, indicated by a large number of focal adhesions, and higher correlation between the orientations of actin filaments and vinculin bands compared to hASCs grown on the glass (uncoated GO substrate). It was also found that the GO films showed the stronger affinity for hASCs than the glass. In addition, the GO film proved to be a suitable environment for the time-dependent viability of hASCs. The enhanced differentiation of hASCs included osteogenesis, adipogenesis, and epithelial genesis, while chondrogenic differentiation of hASCs was decreased, compared to tissue culture polystyrene as a control substrate. The data obtained here collectively demonstrates that the GO film is an efficient substratum for the adhesion, proliferation, and differentiation of hASCs.

4. Jangho Kim*, YR Kim*, H Seonwoo, KT Lim, YJ Kim, YH Choung, JH Chung. "Graphene-Incorporated Chitosan Substrata for Adhesion and Differentiation of Stem Cells." Journal of Materials Chemistry B (Communication, Accepted, *equal contribution, Selected as One of the Most Read Articles in JMC-B in January, 2013)).

Abstract: A simple method that uses graphene to fabricate nanotopographic substrata was reported for stem cell engineering. Graphene-incorporated chitosan substrata promoted adhesion and differentiation of human mesenchymal stem cells (hMSCs). In addition, we proposed that nanotopographic cues of the substrata could enhance cell-cell and cell-material interactions for promoting functions of hMSCs.

5. AL Lim*, Jangho Kim*, KT Lim, H Seonwoo, YH Choung, HW Choung. CS Cho, PH Choung, JH Chung. "Effects of Micro-Electric Current Stimulation on Human Dental Pulp Stem Cells." Tissue Engineering and Regeneration Medicine (Under Review) (*equal contribution).

Abstract: Human dental pulp stem cells (hDPSCs) provide new opportunities in tissue engineering and regenerative medicine because of their remarkable self-renewal capability, rapid proliferation rate, and multiple differentiation potentials. We report an efficient method for the modulation of hDPSC proliferation and differentiation by micro-electric current stimulation (mES) without using chemical agents, such as serum or induction media. We used response surface analysis to find that a working micro-current of 38 µA cued higher hDPSC proliferation compared with other working conditions. Electro-stimulation altered the expressions of intracellular and extracellular proteins compared to those in unstimulated cells. mES with 0.5 and 38 µA current intensity significantly increased osteocalcin (OCN) expression in hDPSCs, whereas mES with 75.5 µA current intensity significantly decreased OCN expression. mES at 38 and 75.5 µA decreased expression and that at 0.5 µA slightly decreased expression of neurofilaments (NF-L) in hDPSCs compared with the levels in hDPSCs cultured without mES. Our findings indicate that mES may induce hDPSC proliferation and differentiation, allowing application to hDPSCs-based bioengineering.

6. Jangho Kim, SW Kim, SJ Choi, KT Lim, JB Lee, H Seonwoo, PH Choung, KH Park, CS Cho, YH Choung, JH Chung. "A Healing Method of Tympanic Membrane Perforations Using Three-Dimensional Porous Chitosan Scaffolds." Tissue Engineering: Part A, 2011:17(21-22): 2763-2772.

Abstract: Both surgical tympanoplasty and paper patch grafts are frequently procedured to heal tympanic membrane (TM) perforation or chronic otitis media, despite their many disadvantages. In this study, we report a new healing method of TM perforation by using three-dimensional (3D) porous chitosan scaffolds (3D chitosan scaffolds) as an alternative method to surgical treatment or paper patch graft. Various 3D chitosan scaffolds were prepared; and the structural characteristics, mechanical property, in vitro biocompatibility, and healing effects of the 3D chitosan scaffolds as an artificial TM in in vivo animal studies were investigated. A 3D chitosan scaffold of 5 wt.% chitosan concentration showed good proliferation of TM cells in an in vitro study, as well as suitable structural characteristics and mechanical property, as compared with either 1% or 3% chitosan. In in vivo animal studies, 3D chitosan scaffold were able to migrate through the pores and surfaces of TM cells, thus leading to more effective TM regeneration than paper patch technique. Histological observations demonstrated that the regenerated TM with the 3D chitosan scaffold consisted of three (epidermal, connective tissue, and mucosal) layers and were thicker than normal TMs. The 3D chitosan scaffold technique may be an optimal healing method used in lieu of surgical tympanoplasty in certain cases to heal perforated TMs.

7. Jangho Kim, SJ Choi, KT Lim, PH Choung, JH Bae, YH Choung, JH Chung. "Tympanic Membrane Regeneration Using a Water-Soluble Chitosan Patch." Tissue Engineering Part A, 2010:16(1): 225-232.

Abstract: Chronic otitis media or tympanic membrane (TM) perforation is one of the most common otologic diseases. Surgical tympanoplasty remains the best treatment option despite the fact that paper patches are frequently used. Although paper patches are not biocompatible or effective, tympanoplasty is an expensive, complex surgery. Tissue engineering techniques offer a new treatment strategy for TM regeneration. In this study, novel tissue-engineered artificial eardrums were fabricated from water-soluble chitosan, which is known to be a good wound-healing biomaterial. The characteristics, cytotoxicity, and healing effects of several water-soluble chitosan patches (WSCPs) made using various concentrations of water-soluble chitosan and glycerol were investigated. The optimal WSCP was fabricated with 3% water-soluble chitosan and 3% glycerol, and it had a thickness of about 35 mm, a tensile strength of 7MPa, a percent elongation of 101%, a hydrophilic surface, and no cytotoxicity. In vivo studies showed that the WSCPs were more effective than spontaneous healing for the repair of traumatic TM perforations. The healed TMs to which WSCPs were applied had a much higher density of collagen fibers and a better lamina propria layer structure than spontaneously healed TMs.

8. Jangho Kim, PH Choung, IY Kim, KT Lim, HM Son, YH Choung, CS Cho, JH Chung. "Electrospun Nanofibers Composed of Poly(ε-caprolactone) and Polyethylenimine for Tissue Engineering Applications." Materials Science and Engineering C, 2009;29:1725-1731. Selected as Top 25 Hottest Articles in Materials Science and Engineering: C (January to June 2009).

Abstract: Poly(ε-caprolactone) (PCL) electrospun nanofibers have been reported as a scaffold for tissue engineering application. However, high hydrophobicity of PCL limits use of functional scaffold. In this study, PCL/polyethylenimine (PEI) blend electrospun nanofibers were prepared to overcome the limitation of PCL ones because the PEI as a cationic polymer can increase cell adhesion and can improve the electrospinnability of PCL. The structure, mechanical properties and biological activity of the PCL/PEI electrospun nanofibers were studied. The diameters of the PCL/PEI nanofibers ranged from 150.4±33 to 220.4±32 nm. The PCL/PEI nanofibers showed suitable mechanical properties with adequate porosity and increased hydrophilic behavior. The cell adhesion and cell proliferation of PCL nanofibers were increased by blending with PEI due to the hydrophilic properties of PEI.

9. Jangho Kim, JH Bae, KT Lim, PH Choung, JS Park, SJ Choi, AL Im, ET Lee, YH Choung, JH Chung. "Development of Water-Insoluble Chitosan Patch Scaffold to Repair Traumatic Tympanic Membrane Perforations." Journal of Biomedical Materials Research Part A, 2009;90:446-455.

Abstract: Perforated tympanic membranes (TM) and otitis media can be managed with a paper patch or tympanoplasty. However, a paper patch is not biocompatible and tympanoplasty requires complex aseptic surgical procedures. A novel biocompatible patch with a water-insoluble chitosan as the main component was prepared. Optimal mechanical characteristics of a water-insoluble chitosan patch scaffold (CPS) was approximately 40 μm in thickness, 7 MPa in tensile strength and 107% in percent elongation, even though the characteristics varied significantly depending on the concentrations of chitosan and glycerol. SEM of the CPSs showed a very smooth surface as compared with that of the paper patches. These CPSs showed no cytotoxicity and had stimulating effect on the proliferation of TM cells in in vitro study. In in vivo study, 4 (21.1%) and 17 (89.5%) TMs out of 19 adult rats with CPSs showed no perforations at 1 and 2 weeks, respectively. However, left control TMs showed healing of 0 (0%) at 1 week and 18 (94.7%) at 2 weeks. TEM findings of regenerated eardrums using CPSs showed thinner, smoother, and more compact tissues than spontaneously healed eardrums. A CPS was more effective than spontaneous healing to repair traumatic TM perforations.

10. Jangho Kim, KT Lim, PH Choung, YH Choung, CS Cho, JH Chung. "Mechanical Stimulation of Mesenchymal Stem Cells for Tissue Engineering." Tissue Engineering and Regeneration Medicine, 2009;6(1-3):199-206.

Abstract: Tissue engineering is a rapidly growing field that utilizes cell/scaffolds constructs with chemical signaling molecules as potential therapeutic products for tissue regeneration. Mesenchymal stem cells (MSCs) are widely used in tissue engineering applications. Recently, it has been recognized that understanding mechanical stimulation is key to the development of efficient and controllable methods to stimulate the differentiation of MSCs. In particular, a number of studies have indicated that mechanical stimuli and chemical signals have a synergistic effect on the differentiation of MSCs and tissue formation or regeneration. In this review, we discuss various mechanical stimuli techniques, and the effects of mechanical stimuli on MSCs and tissue engineering applications. Furthermore, we propose future research directions with respect to the application of mechanical stimuli to MSCs in tissue engineering.

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