• 한국미생물·생명공학회지
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• 제23권5호
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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.

• Journal of Microbiology and Biotechnology
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• 제5권3호
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• pp.163-166
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• 1995

Chemical modification of gelatin-based macroporous microcanier beads was achieved by increasing the charge density through incorporation of (diethylamino)ethylchloride-hydrochloride (DEAE:CI-HCI) or lysine, and this significantly improved the attachment and growth of HepG2 cells. When microcarriers were modified by the addition of 2% lysine, positive charge density was 0.95 meq/g-caniers. In case of modification of microcarriers with DEAE:CI-HCI, positive charge density was 0.6 meq/g-caniers. An increase in charge density of the microcaniers to improve cell attachment has facilitated the growth of the cells on macroporous gelatin microcaniers. Also, final HepG2 cell concentration cultivated on modified beads with DEAE:CI-HCI was increased up to $10^7$ cells/ml. This was 2-3 times higher than that obtained with unmodified macroporous gelatin microcarriers.

• 한국분말재료학회지
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• 제18권4호
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• pp.347-358
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• 2011

Two different schemes were adopted to fabricate ordered macroporous structures with face centered cubic lattice of air spheres. Monodisperse polymeric latex suspension, which was synthesized by emulsifier-free emulsion polymerization, was mixed with metal oxide ceramic nanoparticles, followed by evaporation-induced self-assembly of the mixed hetero-colloidal particles. After calcination, inverse opal was generated during burning out the organic nanospheres. Inverse opals made of silica or iron oxide were fabricated according to this procedure. Other approach, which utilizes ceramic precursors instead of nanoparticles was adopted successfully to prepare ordered macroporous structure of titania with skeleton structures as well as lithium niobate inverted structures. Similarly, two different schemes were utilized to obtain disordered macroporous structures with random arrays of macropores. Disordered macroporous structure made of indium tin oxide (ITO) was obtained by fabricating colloidal glass of polystyrene microspheres with low monodispersity and subsequent infiltration of the ITO nanoparticles followed by heat treatment at high temperature for burning out the organic microspheres. Similar random structure of titania was also fabricated by mixing polystyrene building block particles with titania nanoparticles having large particle size followed by the calcinations of the samples.

• 한국세라믹학회지
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• 제47권6호
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• pp.553-559
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• 2010

The synthesis behavior of nanoporous silica aerogel in the macroporous ceramic structure was observed using TEOS as a source material and glycerol as a DCCA(dry control chemical additive). Silica aerogel in the macroporous ceramic structure were synthesized through a sono-gel process. The wet gel in the macroporous ceramic structure were aged in ethanol for 72 h at $50^{\circ}C$. The aged wet gel was dried under supercritical drying condition. The addition of glycerol has a role of giving the uniform pore size distribution. The reproducibility of aerogel in the macroporous ceramic was improved in the glycerol(0.05 mol%) added to the silica sol and TEOS : $H_2O$=1 : 12.

• 한국세라믹학회지
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• 제48권5호
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• pp.360-367
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• 2011

Macroporous silicon carbide (SiC) ceramics were fabricated by powder processing and polymer processing using carbon-filled polysiloxane as a precursor. The effects of the starting SiC polytype, template type, and template content on porosity and flexural strength of macroporous SiC ceramics were investigated. The ${\beta}$-SiC powder as a starting material or a filler led to higher porosity than ${\alpha}$-SiC powder, owing to the impingement of growing ${\alpha}$-SiC grains, which were transformed from ${\beta}$-SiC during sintering. Typical flexural strength of powder-processed macroporous SiC ceramics fabricated from ${\alpha}$-SiC starting powder and polymer microbeads was 127 MPa at 29% porosity. In contrast, that of polymer-processed macroporous SiC ceramics fabricated from carbon-filled polysiloxane, ${\beta}$-SiC fillers, and hollow microspheres was 116MPa at 29% porosity. The combination of ${\alpha}$-SiC starting powder and a fairly large amount (10 wt%) of $Al_2O_3-Y_2O_3$ additives led to macroporous SiC ceramics with excellent flexural strength.

• 한국세라믹학회지
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• 제46권1호
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• pp.35-40
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• 2009

Using zirconia and poly (methyl methacrylate-coethylene glycol dimethacrylate) (PMMA) microbeads, macroporous zirconia ceramics were fabricated by a simple pressing method. Effects of template size and content on microstructure, porosity, and flexural and compressive strengths were investigated in the processing of the macroporous zirconia ceramics. Three different sizes of microbeads (8, 20, and $50{\mu}m$) were used as a template for fabricating the macroporous ceramics. The porosity increased with increasing the template size at the same template content. The flexural and compressive strengths were primarily influenced by the porosity rather than the template size. However, the strengths increased with decreasing the template size at the same porosity. By controlling the template size and content, it was possible to produce macroporous zirconia ceramics with porosities ranging from 58% to 75%. Typical flexural and compressive strength values at 60% porosity were ${\sim}30\;MPa$ and ${\sim}75\;MPa$, respectively.

• 한국분말재료학회지
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• 제18권3호
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• pp.269-276
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• 2011

The synthesis behavior of nanoporous silica aerogel in the macroporous ceramic structure was observed using TEOS as a source material and glycerol as a dry control chemical additive (DCCA). Silica aerogel in the macroporous ceramic structure was synthesized via sono-gel process using hexamethyldiazane (HMDS) as a modification agent and n-hexane as a main solvent. The wet gel with a modified surface was dried at $105^{\circ}C$ under ambient pressure. The addition of glycerol appears to give the wet gel a more homogeneous microstructure. However, glycerol also retarded the rate of surface modification and solvent exchange. Silica aerogel completely filled the macroporous ceramic structure without defect in the condition of surface modification (20% HMDS/nhexane at 36hr).

• Bulletin of the Korean Chemical Society
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• 제25권11호
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• pp.1671-1675
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• 2004

A simple method for simultaneous recovery and reuse of $OsO_4$ and alkaloid ligand in the asymmetric dihydroxylation of olefins has been developed by using macroporous alkaloid resins bearing residual vinyl groups.

• Membrane and Water Treatment
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• 제7권6호
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• pp.555-571
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• 2016

Heavy metal contamination has attracted considerable attention during recent decades due to the potential risk brought about for human beings and the environment. Several adsorbent materials are utilized for the purification of contaminated water resources among which chitosan is considered as an appropriate alternative. Copper is a heavy metal contaminants found in several industrial wastewaters and its adsorption on porous and macroporous chitosan membranes is investigated in this study. Membranes are prepared by phase inversion and particulate leaching method and their morphology is characterized using SEM analysis. Batch adsorption experiments are performed and it is found that copper adsorption on macroporous chitosan membrane is higher than porous membrane. The iso-steric heat of adsorption was determined by analyzing the variations of temperature to investigate its effect on adsorption characteristics of macroporous chitosan membranes. Furthermore, desorption experiments were studied using NaCl and EDTA as eluants. The mechanism of copper adsorption was also investigated using XPS spectroscopy which confirms simultaneous occurrence of chelation and electrostatic adsorption mechanisms.

• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.620-627
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• 1998

For chemical microsensors such as humidity and gas sensors, it is essential to obtain a single pore with a large inner surface and straight structure. In this paper, cylindrical macroporous silicon layers have been formed of p-silicon substrate by anodization in HF-ethanol-water solution with an applied current. The pores grew normal to the (100) surface and were uniformly distributed. The pore diameter was approximately $1.5~2{\mu}m$ with a depth of $20~30{\mu}m$ and the pores were not interconnected, which are in sharp contrast to the porous silicon reported previouly for similarly doped p-Si. Porous silicon diaphragms 18 to $200{\mu}m$ thick were formed by anistropic etching in TMAH solution and then anodization. The fabrication of macroporous silicon and free-standing diaphragms is expected to offer applications for microsensors, micromachining, and separators.