• Polymer(Korea)
• /
• v.25 no.3
• /
• pp.318-326
• /
• 2001

PLLA scaffold loaded with gentamicin sulfate (GS) was prepared by emulsion freeze-drying method for the prevention of infection and the improvement of wettability. i.e., the cell- and tissue-compatibility. GS-loaded PLLA scaffolds were characterized by scanning electron microscopy (SEM), mercury porosimetry and blue dye intrusion, and the GS release pattern was analyzed by high performance liquid chromatography (HPLC). GS-loaded PLLA scaffolds with porosity above 50%, medium pore size ranging from 30 to 57 ${\mu}{\textrm}{m}$ (with larger pore diameters greater than 150 ${\mu}{\textrm}{m}$), and specific pore area in the range of 35 to 75($m^2$ /g )were manufactured by varying processing parameter as GS concentration. It was observed that GS-loaded PLLA scaffolds were highly porous with good interconnections between pores for allowing cell adhesion and growth. These scaffolds may be applicable for scaffold as structures that facilitate either tissue regeneration or repair during reconstructive operations.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.02a
• /
• pp.196-196
• /
• 2011

팔라듐-구리 합금 분리막은 세륨산화물로 전처리된 다공성 니켈 지지체 위에 마그네트론 스퍼터 공정과 구리리플로우 공정에 의해 제조되었다. 스퍼터 공정은 얇고 치밀한 팔라듐 합금 분리막 증착을 위해 아주 효과적이다. 본 연구에서는 고온 스퍼터 공정에 의해 증착된 팔라듐 상부에 유동성과 열적확산이 우수한 구리를 코팅한 후, 반도체 분야에서 기가 패턴 매립시 사용하는 구리리플로우 공정을 도입하였다. 구리리플로우 공정은 치밀하고 미세기공이 존재하지 않는 표면을 구현하고 무한대의 수소 투과도를 가능하게 한다. 이로써 마그네트론 스퍼터에 의해 $200^{\circ}C$에서 팔라듐과 구리를 순차적으로 코팅한 후, $700^{\circ}C$에서 2시간 구리리플로우 공정을 실시하여 $7.5{\mu}m$ 두께의 팔라듐-구리 합금 분리막이 제조되었다. 세륨산화물(CeO2)은 고온에서 장시간 운전하는 동안 다공성 니켈 지지체의 금속성분이 팔라듐 합금층으로 확산하는 금속의 확산 문제를 개선하고자 지지체와 코팅층 사이에 확산방지막으로 도입되었으며, 균일한 스퍼터 증착을 위해 평탄한 표면의 지지체를 구현하였다. 투과도 테스트는 100-400kPa 의 압력차, 673-773K 의 온도 조건에서 순수한 수소가스로 실시하였다. 표면 미세기공이 없는 치밀한 팔라듐-구리 합금 분리막은 혼합가스에서 질소의 투과 없이 수소만을 투과하는 무한대의 우수한 분리도를 나타내었으며, 상용온도 $500^{\circ}C$에서 12.6ml/$cm^2{\cdot}min{\cdot}atm$의 수소 투과 능력을 보였다. 본 연구에 의해 제조된 팔라듐-구리 합금 분리막은 표면 미세기공이 없는 치밀한 분리막 제조를 가능하게 하였으며 열팽창계수가 팔라듐과 매우 비슷한 세륨산화물($CeO_2$)로 인해 지지체층과 코팅층과의 접합력이 향상되고 수소취성에 강하고 높은 열적 안정성을 갖는다.

• Polymer(Korea)
• /
• v.37 no.5
• /
• pp.649-655
• /
• 2013

In order to use as supporters for the reinforced composite fuel cell membrane, poly(acrylic acid)-grafted porous polytetrafluoroethylenes (PTFEs) were prepared via introduction of poly(acrylic acid) graft chains by a radiation grafting method. FTIR was utilized to confirm the successful introduction of poly(acrylic acid) graft polymer chains into the porous PTFEs. Contact angles were examined to observe the hydrophilicity of the surface of the prepared substrates. The result indicates that the hyrophilicity of the surface in the prepared substrates increases with an increase in the number of hydrophilic polymer chains. FE-SEM, gurley number, and tensile strength were also utilized to characterize the prepared substrates.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.2
• /
• pp.58-65
• /
• 2016

This study was a preparatory experiment aimed the development of membrane scaffolds for tissue engineering. A PCL composite solution contained sodium chloride(NaCl). PCL porous membrane scaffolds were formed on a glass casting plate using a film applicator and immersed in distilled water to remove the NaCl reaching after drying. NaCl was used as a pore former for a 3 dimensional pore net-work. The dry condition parameters were $4^{\circ}C$, room temperature (RT) and $40^{\circ}C$ for each different temperatures in the drying experiment. SEM revealed the morphology of the pores in the membrane after drying and evaluated the in vitro cytotoxicity for basic bio-compatibility. The macro and micro pores existed together in the scaffold and showed a 3-dimensional pore net-working morphology at RT. The in vitro cytotoxicity test result was "grade 2" in accordance with the criterion for cytotoxicity by ISO 10993-5. The dry condition affected the formation of a 3 dimensional pore network and micro and macro pores. Therefore, these results are expected provide the basic process for the development of porous membrane scaffolds to control degradation and allow drug delivery.

• Korean Chemical Engineering Research
• /
• v.44 no.2
• /
• pp.160-165
• /
• 2006

A Pd-Cu-Ni alloyed hydrogen membrane has fabricated on porous nickel support formed by nickel powder. Porous nickel support made by sintering shows a strong resistance to hydrogen embrittlement and thermal fatigue. Plasma surface modification treatment is introduced as pre-treatment process instead of conventional HCl wet activation. Nickel was electroplated to a thickness of $2{\mu}m$ in order in to fill micropores at the nickel support surface. Palladium and copper were deposited at thicknesses of $4{\mu}m$ and $0.5{\mu}m$, respectively, on the nickel coated support by DC sputtering process. Subsequently, copper reflow at $700^{\circ}C$ was performed for an hour in $H_2$ ambient. And, as a result PdCu-Ni composite membrane has a pinhole-free and extremely dense microstructure, having a good adhesion to the porous nickel support and infinite hydrogen selectivity in $H_2/N_2$ mixtures.

• Journal of Periodontal and Implant Science
• /
• v.28 no.4
• /
• pp.577-604
• /
• 1998

chitosan은 골치유증진 및 골세포의 분화를 촉진하는 것으로 알려진 천연의 생분해성 고분자이다. 이연구에서는 chitosan 및 chitosan/tricalcium phosphate(TCP) 다공성 기질을 제조하여 골이식재 및 조직공학적 골형성을 위한 3차원적 세포배양 지지체로서의 가능성을 평가하고자 하였다. chitosan 용액 및 TCP가 포함된 chitosan 용액을 동결건조함으로써 소공의 크기가 $100-200{\mu}m$인 스폰지형태의 chitosan 및 chitosan/TCP 다공성 기질을 제작하였다. 골이식재로서의 효과를 평가하기 위하여 백서의 두개골 결손부에 제작된 chiosan 및 chitosan/TCP 다공성 기질을 각각 이식하고 2주 및 4주 후에 동물을 희생하여 조직학적으로 치유양상을 관찰하였다. 조직공학적 골형성을 위한 세포배양 지지체로서의 가능성을 평가하기 위하여 백서 태자의 두개골에서 분리된 골아세포를 chitosan 및 chitosan/TCP 다공성 기질에 각각 접종하고 56일간 배양하면서 각 기간 별로 세포수, 염기성 인산효소 활성, 축적된 calcium의 양을 측정하였고 배양된 세포-기질 혼합체를 광학현미경 및 주사전자현 미경하에서 조직학적 관찰을 시행하였다. 백서 두개골결손부에 이식된 chitosan 및 chiosan/TCP 다공성 기질은 별다른 이물반응 없이 자연 분해되면서 신생골조직 내에 매립되었으며 이식하지 않은 대조군에 비해 유의하게 높은 신생골형성 효과를 나타내어 우수한 골전도성이 있음이 확인되었다. 신생골형성 양상이나 형성된 양에 있어서 두 가지 기질간의 유의한 차이는 없었다. 골아세포-기질 혼합체의 배양결과, 접종후 배양 28일 경과 시까지 골아세포수는 지속적으로 증가하다가 이후에는 5 8일까지 성장정도가 둔화되었다. 염기성 인산효소의 활성 및 calcium 축적량은 접종후 배양시간경과에 따라 56일까지 지속적으로 증가하였다. 세포수 및 염기성 인산효소의 활성에서 두 기질간의 유의한 차이는 없었고, calcium 축적량에 있어서는 chitosan/TCP 기질에서 유의하게 높았고 증가속도도 컸다. 배양된 골아세포가 접종된 다공성 기질의 조직학적 관찰결과, 골아세포는 다공성 기질에 잘 부착하여 중층의 형태로 성장하면서 광화된 골기질을 형성함이 관찰되었다. 배양 14일부터 작은 골편형태의 골형성이 기질 표면에 부착되어 관찰되었고, 배양기간이 길어짐에 따라 성장하여 배양 56일째에는 상당한 양의 광화된 골질이 형성됨이 관찰되었다. 배양 56일 경과후의 광화된 골질의 양은 chitosan/TCP 기질에서 더 많았다. 이 연구의 결과, chitosan 및 chitosan/TCP 다공성 기질이 골이식재로서 뿐만 아니라, 조직공학적 골형성에 적용되는 골아세포의 배양을 위한 3차원구조의 세포지지체로 이용되어 골재생술식에 유용한 생체재료로 활용될 수 있음이 확인되었다.

• Polymer(Korea)
• /
• v.28 no.5
• /
• pp.382-390
• /
• 2004

One of the significant natural bioactive materials is demineralized bone particle (DBP) whose has a powerful induce. of new bone growth. In this study, we developed the DBP loaded poly-lactide (PLA) and poly(L-lactide-co-glycolide) (PLGA) scaffolds for the possibility of the application of the tissue engineered bone. PLA/DBP and PLGA/DBP scaffolds were prepared by solvent casting/salt leaching method and were characterized by porosimeter, scanning electron microscopy. BMSCs were stimulated by osteogenic medium and characterized by histological stained Wright-Giemsa, Alizarin red, von Kossa, and alkaline phosphate activity (ALP). DBP impregnated scaffolds with BMSCs were implanted into the back of athymic nude mouse to observe the effect of DBP on the osteoinduction compared with control scaffolds. It can be observed that the porosity was above $90.2\%$ and the pore size was above 69.1$\mu$m. BMSCs could be differentiated into osteoprogenitor cells as result of wright-giemsa, alizarin red, von Kossa and ALP staining. In in vivo study, we could observed calcification region in PLA/DBP and PLGA/DBP groups, but calcification did not occur almost in control scaffolds. From these results, it seems that DBP as well as BMSCs play an important role for bone induction in PLA/DBP and PLGA/DBP scaffolds.

• Polymer(Korea)
• /
• v.32 no.6
• /
• pp.516-522
• /
• 2008

Biodegradable polymers have been used extensively as scaffolding materials to regenerate new tissues and the ingrowth of tissue have been reported to be dependent directly of the porosity, pore diameter, pore shape, and porous structure of the scaffold. In this study, porous poly (L-lactide-co-glycolide) (PLGA) scaffolds with five different pore sizes were fabricated to investigate the effect of pore sizes for AF tissue regeneration. Cellular viability and proliferation were assayed by MTT test. Hydroxyproline/DNA content of AF cells on each scaffold was measured. sGAG analyses were performed at each time point of 2 and 6 weeks. Scaffold seeded AF cells were implanted into the back of athymic nude mouse to observe the difference of formation of disc-like tissue depending on pore size in vivo. We confirmed that scaffold with $180{\sim}250{\mu}m$ pores displayed high cell viability in vitro and produced higher ECM than scaffold with other pore sizes in vivo.

• Resources Recycling
• /
• v.30 no.2
• /
• pp.68-74
• /
• 2021

This study investigated formaldehyde (HCHO) removal by preparing porous supports using domestic low-grade silica coated with Co-ZSM5 and Cu-ZSM5 as the catalysts. First, the sample of the raw material for the support contained 90% silica with quartz crystal phase, which was confirmed as low-grade silica. According to Energy-dispersive X-ray spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FT-IR) analyses, the catalysts, Co-ZSM5 and Cu-ZSM5, were successfully coated on the surface of the porous silica supports. During the removal test of HCHO using the prepared Co-ZSM5 and Cu-ZSM5 coated beads, depending on the reaction temperature, the Co-ZSM5 coated beads exhibited higher removal efficiencies (>97%) than the Cu-ZSM5 beads at 200 ℃. The higher efficiency of the Co-ZSM5 coating may be attributed to its superior surface activity properties (BET surface area and pore volume) that lead to the favorable HCHO decomposition. Therefore, Co-ZSM5 was determined to be the suitable catalyst for removing HCHO as a coating on a porous support fabricated using domestic low-grade silica.

• Journal of the Korean Electrochemical Society
• /
• v.26 no.4
• /
• pp.71-79
• /
• 2023

In this study, we employed anionic, cationic, and nonionic surfactants for the hydrophilization of porous substrates used in the fabrication of pore-filling membranes. We investigated the extent of hydrophilization based on the type of surfactant, its concentration, and immersion time. Furthermore, we used the hydrophilized substrates to produce pore-filling anion exchange membranes and compared their ion conductivity to determine the optimal hydrophilization conditions. For the ionic surfactants used in this study, we observed that hydrophilization progressed rapidly from the beginning of immersion when the applied concentration was 3.0 wt%, compared to lower concentrations (0.05, 0.5, and 1.0 wt%). In contrast, for the relatively larger molecular weight non-ionic surfactants, smooth hydrophilization was not observed. There was no apparent correlation between the degree of hydrophilization and the ion conductivity of the anion exchange membrane. This discrepancy suggests that an excessive hydrophilization process during the treatment of porous substrates leads to excessive adsorption of the surfactant on the sparse surfaces of the porous substrate, resulting in a significant reduction in porosity and subsequently decreasing the content of polymer electrolyte capable of ion exchange, thereby greatly increasing the electrical resistance of the membrane.