• Journal of Pharmaceutical Investigation
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• v.32 no.1
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• pp.21-26
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• 2002

The primary culture of human nasal epithelial cell monolayer was performed on a Transwell. The effect of various factors on the tight junction formation was observed in order to develop an in vitro experimental system for nasal transport studies. Human nasal epithelial cells, collected from human normal inferior turbinates, were plated onto diverse inserts. After 4 days, media of the apical surface was removed for air-liquid interface (ALI) culture. Morphological characteristics was observed by transmission electron microscopy (TEM). A polyester membrane of $0.4\;{\mu}m$ pore size was determined as the most effective insert based on the change in the transepithelial electric resistance (TEER) value as well as the $^{14}C-mannitol$ transport study. The ALI method was effective in developing the tight junction as observed in the further increase in the TEER value and reduction in the permeability coefficient $(P_{app})$ of $^{14}C-mannitol$ transport. Results of the transport study of a model drug, budesonide, showed that the primary culture system developed in this study could be further developed and applied for in vitro nasal transport studies.

• Bulletin of the Korean Chemical Society
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• v.20 no.9
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• pp.1078-1084
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• 1999

A synthetic cecropin A(1-13)-melittin(1-13) [CA-ME] hybrid peptide was known to be an antimicrobial peptide having strong antibacterial, antifungal and antitumor activity with minimal cytotoxic effect against human erythrocyte. Analogues were synthesized to investigate the influences of the flexible hinge region of CA-ME on the antibiotic activity. Antibiotic activity of the peptides was measured by the growth inhibition against bac-terial, fungal and tumor cells and vesicle-aggregating or disrupting activity. The deletion of Gln-Gly-Ile (P1) or Gly-Gln-Gly-Ile-Gly (P3) from CA-ME brought about a significant decrease on the antibiotic activities. In contrast, Gly-Ile-Gly deletion (P2) from CA-ME or Pro insertion (P5) instead of Gly-Gln-Gly-Ile-Gly of CA-ME retained antibiotic activity. This result indicated that the flexible hinge or β-bend structure provided by Gly-Gln-Gly-Ile-Gly, Gln-Gly, or Pro in the central region of the peptides is requisite for its effective antibiotic activity and may facilitate easily the hydrophobic C-terminal region of the peptide to penetrate the lipid bilayers of the target cell membrane. In contrast, P4 and P6 with Gly-Gln-Gly-Pro-Gly or Gly-Gln-Pro in the central region of the peptide caused a drastic reduction on the antibiotic activities. This result suggested that the con-secutive β-bend structure provided by Gly-Gln-Gly-Pro-Gly or Gly-Gln-Pro in the central hinge region of the peptide seems to interrupt the ion channel/pore formation on the target cell membranes.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.279-289
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• 1995

The most important object of periodontal treatment is the perfect regeneration of destructed periodontal tissue. The healing of periodontal lesion is affected by several cells & factors, which result in formation of long juntional epithelium, root resorption, bony ankylosis or connective tissue attachment. And ideal healing is enhanced by epithilial exclusion or periodontal ligament cell activation. In this investigation, I studied the effect of Zizyphus Fructus extract which enhances biologic activity& collagen synthesis, on the chemotaxis & cell nature. The cells were obtained from interdental area & middle third area of the freshly extracted teeth for the orthodontic purpose. And they were fully incubated in${\alpha}-MEM$ solution containing $100{\mu]g/ml$ penicillin & $100{\mu]g/ml$ streptomycin followed by 6 generation incubation. The test cells were collected by trypsin-EDTA & centrifuge in the fully incubated cells, counted by Hernacyotmeter, incbated $5{\times}10^5/ml$ cells for 24 hours, re-incubated 24 hours in media containing natural extract and photographed. The cells were incubated for 4 hours in 48 well microchemotaxis chamber bisecting upper & lower chamber by 8ug/m pore polycarbonate membrane coating 5mg/ml gelatin solution. The migrated cells in microscope were counted, which meaned cell chemotaxis activity. The study had shown that the morphology of cell was spindle-shaped as the control group, and the subextract test groups were not significantly different. In gingival fibroblasts, the chemotaxis effect of PDGF was statistically significant compared to control group. The Zizyphus Fructus extract was more or less enhanced chemotaxis effect and in $1{\mu}g/ml$ concentration the chemotaxis effect was slightly elevated compared with $10{\mu}g/ml$ concentration. But, among the subextracts, it was not significantly defferent. In PDL cells, the chemotaxis effect of PDGF in statistically significant, and the zizyphus Fructus extract had shown the enhanced effect. The effect was slightly higher in $1{\mu}g/ml$ concentration than 10g/ml concentration,and no significance among the subextracts.

• Design & Manufacturing
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• v.15 no.2
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• pp.11-16
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• 2021

Recently, three-dimensional (3D) cell culture systems, which are superior to conventional two-dimensional (2D) vascular systems that mimic the in vivo environment, are being actively studied to reproduce drug responses and cell differentiation in organisms. Conventional two-dimensional cell culture methods (scaffold-based and non-scaffold-based) have a limited cell growth rate because the culture cannot supply the culture medium as consistently as microvessels. To solve this problem, we would like to propose a 3D culture system with an environment similar to living cells by continuously supplying the culture medium to the bottom of the 3D cell support. The 3D culture system is a structure in which microvascular structures are combined under a scaffold (agar, collagen, etc.) where cells can settle and grow. First, we have manufactured molds for the formation of four types of microvessel-mimicking chips: width / height ①100 ㎛ / 100 ㎛, ②100 ㎛ / 50 ㎛, ③ 150 ㎛ / 100 ㎛, and ④ 200 ㎛ / 100 ㎛. By injection molding, four types of microfluidic chips were made with GPPS (general purpose polystyrene), and a 100㎛-thick PDMS (polydimethylsiloxane) film was attached to the top of each microfluidic chip. As a result of observing the flow of the culture medium in the microchannel, it was confirmed that when the aspect ratio (height/width) of the microchannel is 1.5 or more, the fluid flows from the inlet to the outlet without a backflow phenomenon. In addition, the culture efficiency experiments of colorectal cancer cells (SW490) were performed in a 3D culture system in which PDMS films with different pore diameters (1/25/45 ㎛) were combined on a microfluidic chip. As a result, it was found that the cell growth rate increased up to 1.3 times and the cell death rate decreased by 71% as a result of the 3D culture system having a hole membrane with a diameter of 10 ㎛ or more compared to the conventional commercial. Based on the results of this study, it is possible to expand and build various 3D cell culture systems that can maximize cell culture efficiency by cell type by adjusting the shape of the microchannel, the size of the film hole, and the flow rate of the inlet.