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우창희(Chang Hee Woo),최기평(Ghi Pyoung Choi),이세환(Se Hwan Lee),조영삼(Young-Sam Cho) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Firstly, we fabricated PCL (polycaprolactone) wire with 400 and 600 micrometer using extrusion technique. After that, one layer was composed with (PCL wire/ metal wire) repeatedly. Moreover, we stamped nano-patterned mold on the surface of composed layer. The second layer was composed by same process but 90 degree rotated and nano-patterned mold-stamping procedure is also repeated. This layer stacking process was executed repetitively when the height is reached at the designed height. After that, PCL wires became a porous scaffold under the environmental temperature over 60 degrees Celcius. Subsequently, each metal wire was removed from the repeated (PCL wire/metal wire) composition. Consequently, we fabricated the 3D porous PCL scaffold with porosity of 400 or 600 micrometer and surface pattern of dozens nanometers.
Polymer/MWCNT 복합재료의 제작과 분산영향에 따른 기계적 특성 평가
우창희(Chang Hee Woo),이세환(Se Hwan Lee),최기평(Ghi Pyoung Choi),안상현(Sang Hyun Ahn),송기명(Ki Myoung Song),조영삼(Young-Sam Cho) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.4
In the study, we fabricated several types of polymer/MWCNT composites using mechanical stirrering. Firstly, MWCNT was dissolved in acetone by the aid of sonication treatment to enhance the dispersion characteristics. After that, the mixture of polymer and solvent was sonicated and the prepared CNT is added into the mixture. Subsequently, with the mechanical stirrer, we fabricated the composite which is composed with polymer and MWCNT. We investigated the dispersion status using TEM. Furthermore, we analyzed the mechanical characteristics using tensile test and wear test.
ABS/MWCNT 복합재료의 분산 영향에 따른 마모 특성 분석
우창희(Chang Hee Woo),최기평(Ghi Pyoung Choi),이세환(Se Hwan Lee),조영삼(Young-Sam Cho) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Firstly, we fabricated several types of ABS/MWCNT composites using mechanical stirrer. MWCNT was prepared with acetone and sonication treatment to enhance the dispersion characteristics. After that, we added several different weight percent of MWCNT into melted ABS polymer to fabricate ABS/MWCNT composite. For the several different dispersion rate of MWCNT, we varied the operation time of mechanical stirring. With fabricated ABS/MWCNT composite, we analyzed the wear characteristics using abrasion tester. Consequently, we proposed a empirical fitted wear model for ABS/MWCNT composites.
새로운 와이어 네트워크 몰딩 기법을 활용한 Scaffold 제작 및 특성평가
우창희 ( Chang Hee Woo ),김태영 ( Tae Young Kim ),이세환 ( Se Hwan Lee ),최기평 ( Ghi Pyoung Choi ),이승재 ( Seung Jae Lee ),김범수 ( Beom Su Kim ),유형근 ( Hyung Keun You ),조영삼 ( Young Sam Cho ) 한국조직공학·재생의학회 2012 조직공학과 재생의학 Vol.9 No.2s
In this study, we proposed a novel method which has several merits: guaranteed interconnectivity, solvent free, and unnecessary expensive devices. For the proposed novel method named as Wire-Network Molding, firstly, we prepare a mold with designed shape. Secondly, rectangular wires with thickness size 300 μm, 400 μm or 620 μm are inserted to make space for interconnected pore. After that, melted PCL (polycaprolactone) which is one of synthetic polymers with biocompatibility is filled in the mold and the mold is cooled at room temperature. Subsequently, wires are separated from the mold and the mold is removed from PCL. Consequently, the remained PCL has interconnected pores with a configuration of wire-network. To analyze the compressive modulus of the fabricated scaffold, UTM compression test is carried out. Moreover, we compare the compressive modulus of the fabricated scaffold with that of bio-plotter scaffold. Additionally, for scaffolds with 300 μm, 400 μm pore size, cell culture experiments are carried out using human.
우창희(Chang Hee Woo),안상현(Sang Hyun An),최기평(Ki Pyeong Choi),조영삼(Young-Sam Cho) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
In this article, we reported the characterization of mechanical properties for several scaffolds fabricated by different techniques: bio-plotter technique, wire-network molding, and hollow-cylinder-grain assembly. Firstly, we scanned the configuration of scaffolds using micro-CT, calculated the porosities, and constructed numerical models for ABAQUS: a commercial computational analyzing program. Using ABAQUS, effective compressive and shear stiffness are calculated and compared with the experimental results from UTM tests.
Structure and immune activities of pectin from the root bark of Ulmus dividana var. japonica
최재호,우창희,기창석 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-
The root bark of Ulmus dividana var. japonica is a traditional medicine in Korea for inflammatory disorders. Although various hydrophobic compounds of the extract have been extensively explored, the bioactivity of water-soluble compounds is still veiled. In this study, pectin from the root bark of Ulmus dividana var. japonica (PPU) was obtained by hot water extraction and ultrasonication process. PPU consists of homogalacturonan and rhamnogalactronan (RG) regions, which indicates a typical pectin structure. Particularly, PPU has a large amount of galactose unit compared to that of ordinary pectins. We hypothesize that such a galactose-rich structure is a main structure of RG domain, which plays an important role in immune activity. Murine macrophages were significantly activated by PPU treatment, showing M1 marker upregulation. These findings suggest that PPU is a promising material as a natural immunomodulator.