• KSBB Journal
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• v.25 no.4
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• pp.344-350
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• 2010

This paper demonstrates a microfluidic chip incorporating patterned hollow silica beads that can be effectively used for chemotaxis assay. The hollow silica bead has been exploited to develop a carrier for chemoattractant to induce cell migration. The microfluidic chip contains a patterned array of microfabricated docks which can hold only one bead per docking site. The hollow bead placed inside microfluidic chip releases chemotactic reagent (PDGF-BB) around its periphery in a controlled fashion which generates a signal for chemotatic migration of fibroblast cells. The number of cells migrated close to each bead has been assessed. On-chip cell migration assay showed a remarkable result proving the high efficiency and reliable accuracy in quantitative analysis. Therefore, the device could be extensively used in cell migration assay and other various studies related to cellular movements.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3715-3721
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• 2013

In this study, the behavior of cells on the modified surface, and the correlation between the modified substrates and the response of cells is described. A close-packed layer of nano-sized silica beads was prepared on a coverslip, and the adhesion, proliferation, and migration of BALB/3T3 fibroblast cells on the silica layer was monitered. The 550 nm silica beads were synthesized by the hydrolysis and condensation reaction of tetraethylorthosilicate in basic solution. The amine groups were introduced onto the surfaces of silica particles by treatment with 3-aminopropyltrimethoxysilane. The close-packed layer of silica beads on the coverslip was obtained by the reaction of the amine-functionalized silica beads and the (3-triethoxysilyl)propylsuccinic anhydride treated coverslip. BALB/3T3 fibroblast cells were loaded on bare glass, APTMS coated glass, and silica bead coated glass with the same initial cell density, and the migration and proliferation of cells on the substrates was investigated. The cells were fixed and stained with antibodies in order to analyze the changes in the actin filaments and nuclei after culture on the different surfaces. The motility of cells on the silica bead coated glass was greater than that of the cells cultured on the control substrate. The growth rate of cells on the silica bead coated glass was slower than that of the control. Because the close-packed layer of silica beads gave an embossed surface, the adhesion of cells was very weak compared to the smooth surfaces. These results indicate that the adhesion of cells on the substrates is very important, and the actin filaments might play key roles in the migration and proliferation of cells. The nuclei of the cells were shrunk on the weakly adhered surfaces, and the S1 stage in which DNA is duplicated in the cell dividing processes might be retarded. As a result, the rate of proliferation of cells was decreased compared to the smooth surface of the control. In conclusion, the results described here are very important in the understanding of the interaction between implanted materials and biosystems.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.945-951
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• 2012

The effect of photocatalyst-carrying media porosity on the photocatalytic removal efficiency of malodor and VOC of waste air was evaluated when the photocatalytic removal efficiency of porous silica-based media was compared with that of glass bead as control. The amount of photocatalyst coated on the surface of porous silica-based media was observed to be $1,716.3{\mu}g/cm^2$, which was 250% as much as that of nonporous glass bead (control) of $670{\mu}g/cm^2$. The removal efficiencies of hydrogen sulfide and toluene in case of porous silica-based media were observed to be 22% and 82%, respectively, while the removal efficiencies of hydrogen sulfide and toluene in case of nonporous glass bead media were observed to be 19% and 53%, respectively. Therefore, the removal efficiencies of hydrogen sulfide and toluene increased by 16% and 55%, respectively, when the removal efficiencies of porous silica-based media were compared with those of nonporous glass bead media. Thus the increment ratio of the removal efficiency of toluene was observed to be 3.4 times higher than that of hydrogen sulfide.

• Korean Journal of Materials Research
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• v.26 no.3
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• pp.136-142
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• 2016

To study the dispersion factors of silica sol prepared from fumed silica powder, we prepared silica sol under an aqueous system using a batch type bead mill. The dispersion properties of silica sol have a close relationship to dispersion factors such as pH, milling time and speed, the size and amount of zirconia beads, the solid content of fumed silica, and the shape and diameter of the milling impellers. Especially, the silica particles in silica sol were found to show dispersion stability on a pH value above 7, due to the electrostatic repulsion between the particles having a high zeta potential value. The shape and diameter of the impellers installed in the bead mill for the dispersion of fumed silica was very important in reducing the particle size of the aggregated silica. The median particle size ($D_{50}$) of silica sol obtained after milling was also optimized according to the variation of the size and amount of the zirconia beads that were used as the grinding medium, and according to the solid content of fumed silica. The dispersion properties of silica sol were investigated using zeta potential, turbiscan, particle size analyzer, and transmission electron microscopy.

• Journal of agriculture & life science
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• v.43 no.6
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• pp.105-109
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• 2009

Kyungsan nursery complex which has a vast area for the production of various species of fruit tree stocks is in a high demand of virus-free saplings. Apple tree stocks, the most important products, urgently need more rapid and reliable viral diagnosis. In this study, a bead beater was tested because of convenience in dealing with large number of samples. Also, industrial glass bead abrasive (0.4 mm in diameter) at very low cost was used in a disposable way. For bead beater-aided RNA extraction from apple stem tissues, the guanidine thiocyanate method was confirmed to be very reliable. Silca membrane filter tube in connection to vacuum filtering device was strongly suggested for simplifying RNA capture and washing steps. Apple virus detection was confirmed by RT-PCR.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.952-959
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• 2012

The photocatalytic reactor was designed to have improved efficiency by enhancing a light intensity of photocatalytic reactor using a reflector coated on the surface at the outer radius of annular shaped photocatalytic reactor. The improved photocatalytic reactor performed to treat waste air containing malodor and VOC with the enhanced light intensity, of which the effect on their removal efficiency was investigated. The intensities of illumination of the improved photocatalytic reactor filled with porous silica-based media and nonporous glass bead media carrying photocatalyst were observed to increase by 28.5% and 30.1%, respectively, compared to those of photocatalytic reactor without any reflector. Using the improved photocatalytic reactor filled with porous silica-based media and nonporous glass bead media carrying photocatalyst, the removal efficiencies were enhanced by 2~3% and insignificantly, respectively. The removal efficiencies of the optimized photocatalytic reactor with reflectors, filled with porous silica-based media carrying photocatalyst, were observed to increase by 26% and 60%, compared to those of photocatalytic reactor (i.e., 19% and 53%), without any reflector, filled with nonporous glass bead media carrying photocatalyst, for hydrogen sulfide and toluene, respectively. The roughness of used reflector surface was measured to be ca. four times as big as that of a commercial mirror. However, their removal efficiencies are expected to be enhanced by increasing an light intensity resulting from lowering the roughness of used reflector coated on the improved photocatalytic reactor in the future.

• Journal of Energy Engineering
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• v.21 no.1
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• pp.43-46
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• 2012

A fluidized bed drying approach was utilized to the synthesis of water glass based silica aerogel powders. The effects of the fluidized bed drying conditions such as the superficial velocity and temperature of hot air and bead size as well as bead/wet-gel ratio, on the physical properties such as tapping density and productivity of the aerogel powders were systematically investigated. The experimental results showed that the amount of beads mixed with wet-gels in the fluidized bed column has the most profound impact on the fluidization efficiency, greatly enhancing the yield of the aerogel powders up to 98% with a proper bead/wet-gel weight ratio as compared to 72% without using beads. No significant change was observed in the tapping density over a wide range of the fluidized drying condition. Consequently the fluidized bed drying approach shows a good promise as an alternative route for the large-scale production of the aerogel powders.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.354-357
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• 2008

본 연구는 광전자촉매 시스템(PECS) 적용을 위하여 광촉매 금속판과 코팅비드를 제조하여 특성을 고찰하였다. 광촉매 물질의 회수가 용이하고, 실용화하기 위하여 티타늄 금속판을 $400^{\circ}C$에서 $700^{\circ}C$까지 $50^{\circ}C$에서 $100^{\circ}C$간격으로 토치를 사용하여 산화처리 하였으며, 비드의 경우 alumina, glass, silica gel beads에 TTIP([Ti$(OC_3H_7)_4$], Aldrich)을 전구체로 사용하여, 유동층 화학기상증착공정(Fluidized Bed Chemical Vapor Deposition, FB-CVD)으로 박막코팅을 하였다. 광촉매 금속판의 경우 산화처리 후 외관상태와 성분분석 시 최적조건은 $400^{\circ}C{\sim}500^{\circ}C$ 60분간 토치로 산화하였을 때였으며, 광촉매 코팅비드의 경우 silica gel beads가 본연의 다공구조를 나타내며 박막코팅이 되어, 상대적으로 alumina, glass beads에 비해 반응표면적이 크게 나타났다.

• 보존과학연구
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• s.29
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• pp.137-148
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• 2008

Analyses of ancient DNA (aDNA) from archaeological and historical skeletal material are characterized by low quality. Many soil contaminants such as humic acid, fulvic acid, and bone collagen are often co-extracted with aDNA and inhibit amplification by polymerase chain reaction (PCR). In this study, we compared with two methods of DNA extraction by phenolchloroform extraction and silica-bead extraction. In addition, we applied new protocol, ultra sonication based silica-bead extraction method to extract aDNA from some ancient human skeletal remains. This method was more effective by both mitochondrial DNA (mtDNA) and amelogenin gene amplification.

• Applied Chemistry for Engineering
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• v.22 no.4
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• pp.384-389
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• 2011

We made suspension of fumed silica in polyethylene glycol (PEG), studied rheological behavior as functions of contents of silica, dispersion condition, PEG molecular weight, temperature and contents of humidity. Rheological behavior of suspension was determined critical shear rate and rise of viscosity using rheometer AR2000. Suspension were PEGs of molecular weight 200, 400, and 600. Fumed silica suspensions of which silica contents are 5, 7, 9, 13, and 18% were prepared by normal mixing, homogenization and bead milling process. We observed their rheological behaviors at 10, 20, 30, and $40^{\circ}C$. As the PEG molecular weight and contents of silica increase, the critical shear rate was lowered. As the temperature increased, the critical shear rate was increased. Humidity contents of dispersion don't influence on the critical shear rate, but dispersion processes greatly affect the critical shear rate. The critical shear rate of suspensions prepared by the mixing process was the lowest, and that of suspensions prepared by the bead milling process was the highest. The rise in the shear viscosity of suspensions prepared by the mixing process is higher than that of suspensions prepared by the bead milling process. This was dependent on the dispersion condition of silica particle by dispersion process.