• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.715-725
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• 1996

This study represents the synthetic characteristics of styrene-DVB copolymer which is used as a catalyst support for the removal of tritium in CANDU. To evaluate the effect of solvent on the styrene-DVB polymeric support, the solvating power dependent on various kinds and composition of solvents was calculated. In order to synthesize the macroreticular type polymer bead, the following conditions are needed; solvating power should be higher than 1 for 20% of crosslinkage and higher than 3 for 40% of crosslinkage. Stabilization of organic monomers at about $40^{\circ}C$ for more than 2 hours is prerequisite. Removal of solvent prior to drying is preferred for the post-treatment of the bead. The polymer particle size was increased by lowering concentration of surfactant and stirring speed.

• Polymer(Korea)
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• v.30 no.1
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• pp.14-21
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• 2006

Tissue engineering techniques require the use of a porous biodegradable/bioresorbable scaffold, which server as a three-dimensional template for initial cell attachment and subsequent tissue formation in both in vitro and in vivo. Small intestinal submucosa (SIS) has been investigated as a source of collagenous tissue with the potential to be used as biomaterials because of its inherent strength and biocompatibility. SIS-loaded poly(L-lactide-co-glicolide)(PLGA) scaffolds were prepared by solvent casting/particle leaching. Characterizations of SIS/PLGA scaffold were carried out by SEM, mercury porosimeter, and so on. Muscle-derived stem cells can be differentiated in culture into osteoblasts, chondrocytes, and even myoblasts by the controlling the culture environment. Cellular viability and proliferation were assayed by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide(MTT) test. Osteogenic differential cells were analyzed by alkaline phosphatase(ALP) activity. SIS/PLGA scaffolds were implanted into the back of athymic nude mouse to observe the effect of SIS on the osteoinduction compared with controlled PLGA scaffolds. Thin sections were cut from paraffin embedded tissues and histological sections were conducted hematoxylin and eosin (H&E), Trichrome, and von Kossa. We observed that bone formatioin of SIS/PLGA hybrid scaffold as natural/synthetic scaffold was better thean that of only PLGA scaffold. It canb be explained that SIS contains various kinds of bioactive molecules for osteoinduction.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1213-1219
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• 2003

Porous ceramics for microoganism carriers were prepared with amorphous alumina and pore formers by hydrothermal reaction, burn-out and wash-out method. Activated carbon with average size of 67,222, and 405 $\mu\textrm{m}$, organic polymer and inorganic salt were used as pore formers. Specimens were hydrothermally treated at 200$^{\circ}C$ for 24 h, heat-treated at 650$^{\circ}C$ for 5 h, and washed out at 80$^{\circ}C$ for 48 h. The formation of crystalline phase, porosity, pore size distribution and compressive strength were measured. The specimen with activated carbon was transformed to boehmite phase, but organic polymer and inorganic salt inhibited the aquohydroxoy complex gel and crystalline formation. The porous ceramics for microoganism carriers using activated carbon as a pore formers was successfully prepared, which is composed of ${\gamma}$-alumina phase with porosity of above 70 vol% and the compressive strength of 40 kgf/$\textrm{cm}^2$.

• Polymer(Korea)
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• v.31 no.6
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• pp.505-511
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• 2007

Poly(lactide-co-glycolide)(PLGA) and hyaluronic acid (HA) has been widely used as biocompatible scaffold materials to regenerate tissue. In this present study, we fabricated microporous PLGA and HA loaded PLGA scaffolds by a emusion freeze-drying method. In order to confirm that the release profile of cytokine or water-soluble drugs, we manufactured the granulocyte macrophage colony stimulating factor(GM-CSF) loaded PLGA and HA-PLGA scaffold. All scaffolds were characterized using scanning electron microscope(SEM), mercury porosimeter and wettability measurement. Cell proliferation and viability were assessed by a 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) test. The porosity of HA-PLGA scaffold was greater than 95% with the total pore area of $261\;m^2/g$. The HA-FLGA scaffold exhibited well interconnected pores to allow greater cell adhesion and prolixferation. It was proven by higher cell viability in the HA-PLGA scaffold than PLGA alone. This may be due to the enhanced natural properties and higher water retention capacity of HA.

• Microbiology and Biotechnology Letters
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• v.23 no.5
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• pp.499-505
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• 1995

Immobilization of anchorage-dependent animal cells was investigated using macroporous gelatin microcarriers developed in our laboratory. For the observation of the distribution of cells in macroporous beads, Vero-6 cells and CHO cells were cuttured and their distribution in macroporous beads was observed using a confocal microscope. In results, the final concentration of Vero-6 cells and CHO cells on macroporous beads was 2-3 times higher than that on commercial solid microcarriers (Cytodex-3). Also, macroporous microcarriers could hold cells in their macropores. Consequently, the pores protected cells against hydrodynamic shear. Based on Kolmogorov eddy length scale, the smaller eddies (80 $\mu $m) showed the detrimental effect on cells in macroporous beads as compared with 160 $\mu $m of eddies in conventional solid microcarriers.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.80-80
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• 1994

세라믹막을 이용한 oil 폐수 처리의 기초 연구로서 정밀여과용 세라믹막의 제조와 oil(kerosene)-in-water 타입 에멀젼에 대한 막분리 효율이 연구되었다. 정밀여과 막으로서는 압출(extrusion)법으로 성형하여 제조한 $\alpha$-알루미나 튜브(평균 기공크기 0.9 $\mum$)와 이들 튜브(담체)내부에 $ZrO_2$ 또는 $Al_2O_3$ 다공성 박막을 코팅한 2층 구조의 복합막들을 사용하였다. 담체의 높은 투과율 ($1700 l/m^2\cdot h$ at $\Deltap = 1$ atm)을 어느정도 유지하면서 막분리 효율을 증대시킬 수 있는 새로운 슬러리 코팅법이 개발되엇으며, 코팅후 950-1300$\circ$C 에서 열처리한 코팅층의 두께와 평균 기공크기는 각각 5 - 20 $\mum$정도 이었다. 정밀여과막의 특성평가를 위하여 막 제조조건에 따른 코팅층의 두께 및 결함유무를 SEM으로 일단 관찰한 후에 Bubble Point Test와 Mercury Porosimeter를 이용하여 측정한 최대 및 평균 기공반경과 물의 투과량으로부터 막 전체에 대한 결함 유무와 결함의 허용한도등을 비교 분석하였다.

• KSBB Journal
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• v.8 no.5
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• pp.465-472
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• 1993

The comparison of the capabilities of cell growth of four different kinds of commercially available microcarriers was carried out by culturing anchorage-dependent animal cells, Vero-6, in a spinner flask. Using 3 g/l of Cytodex 3, the maximum final cell density was about $1.4{\times}10^6$ cells/ml and increased up to $2.0{\times}10^6$ cells/ml by increasing microcarrier concentration up to 5 g/l. The macroporous collagen microcarriers, VX-100, informatrix, and Cultispher-G showed the final cell concentration of $4{\times}10^6$ cells/ml, $2.1{\times}10^6$ cells/ml, and $3.2{\times}10^6$ cells/ml, respectively at the microcarrier concentration of 5g/1. According to this result, VX-100 showed better cell growth than informatrix and cultispher-G and also showed about 2 fold increase in final cell density comparing to Cytodex 3 solid bead. When the intermittent bead-to-bead transfer technique was introduced in the culture using Cytodex 3 bead and cultispher-G, the result was very successful and the cells grew out very well. The recovered cells by dissolving collagen microcarrier using collagenase enzyme were mostly viable and grew out very well on the surface of the fresh microcarriers.

• Polymer Science and Technology
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• v.15 no.3
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• pp.303-316
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• 2004

균일한 크기의 미세 기공이 규칙적으로 배열되어 있는 다공성 분자체 물질 (porous molecular sieve materials)은 분자 단계의 물질들을 선택적으로 분리 흡착할 수 있는 장점을 가지고 있으며, 이를 이용하여 다양한 화학 반응의 촉매 및 촉매의 담체로서 널리 사용되어 왔다. 미세 기공 물질은 IUPAC 정의에 따르면 세공의 크기에 따라 기공의 직경이 1.5 nm 미만인 마이크로포러스 물질 (microporous materials), 1.5 nm 이상 50 nm 미만의 메조포러스 물질(mesoporous materials), 그리고 50 nm 이상의 매크로포러스 물질 (macroporous materials)로 나누어진다. (중략)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.236-241
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• 2003

산업체 발생 VOC를 효과적으로 처리하는 Biofilter 시스템을 고안하였다. 재질과 다공성이 다른 3기의 시스템으로부터 황화수소, 벤젠, 톨루엔, 크실렌의 단일성분과 복합성분계의 성능을 고찰하였다 저 pH Biofilter(pH 2-3)의 장기운전이 가능하였고 벤젠의 경우 경쟁적 저해를 나타내었으나 일정기간의 순응 이후 혼합처리시 양호한 처리능력을 보여주었다.

• KSBB Journal
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• v.15 no.3
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• pp.285-292
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• 2000

Support media for yeast immobilization was prepared from a porous volcanic rock used as a moisturizer in orchid growing. The rock was broken to the size of 2-3 mm and burned at $600^{\circ}C$ in a furnace in order to remove organic materials blocking the pores or treated with HCI solution or NaOH solution to remove the inorganic dirts by dissolving. Even through both the acid and the akali solution were effective the latter was not recommendable because it broke the pore structure by dissolving the elements of the media. This media was mainly consisted of SiO2 with $Al_2O_3$ as a minor component and CaO and K2O as trace elements. It had the finely developed pores of $15-80\mu\textrm{m}$size. Yeast immobilization capacity of this media was about $5{\times108}$ cells/ml bed which is large enough to be used for the practical applications. Yeast immobilization capacities of Alumina and Cordierite were much smaller than that of silica-based media. Scanning electron micrograph of Cordierite and Alumina showed uneven surfaces and small size of pores in contrast to relatively smooth surface and large pores of silica based media which means that smooth surface and large pores are desirable for the good adsorption of microbes on the media.