• 대한치과의사협회지
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• 제55권9호
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• pp.592-603
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• 2017

Purpose: The effects of various concentrations of ascorbic acid on stem cell spheroids derived from intraoral areas are not known yet. Thus, the purpose of this study is to evaluate the effects of different concentrations of ascorbic acid on the morphology and cellular viability of stem cell spheroids derived from the gingival tissues. Materials and Methods: Stem cells were plated onto silicon elastomer-based concave microwells and grown in the presence of ascorbic acid at concentrations ranging from 0.003% to 0.3%. The morphology of the cells was viewed under an inverted microscope at day 1, 2, 3 and 5. Qualitative live/dead assay and quantitative cellular viability using Cell Counting Kit-8 were performed on day 2 and day 5. Results: Gingiva-derived stem cells formed spheroids irrespective of ascorbic acid concentration in silicon elastomer-based concave microwells. Increase in the diameter of spheroid were seen with higher concentrations of ascorbic acid. Higher cellular viability was seen in higher concentrations of ascorbic acid. Conclusion: Within the experimental setting, the application of ascorbic acid on stem-cell spheroids produced an increase in the size and higher viability with higher dosage. It can be suggested ascorbic acid be applied with stem cell spheroids for tissue engineering purposes.

• Molecules and Cells
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• 제25권3호
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• pp.452-456
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• 2008

The interactions between monocytes and extracellular matrix proteins have been implicated in atherosclerosis pathophysiology. In the present study we evaluated monocyte attachment and migration through oxidized and non-oxidized collagen IV. Monocyte attachment was tested on microwells coated with either native or oxidized collagen IV. Monocyte migration through collagen IV was examined on transwells. Monocytes derived from patients with diabetes mellitus showed an increased ability to attach and migrate through collagen IV as compared to those derived from healthy volunteers. Moreover, control monocytes attached to oxidized collagen at a higher degree, while they migrated through oxidized collagen at a lower degree, as compared to the native protein. Our results also showed the involvement of the alpha2 integrin subunit in the above phenomena suggesting a modified interaction between monocytes and collagen IV in diabetes mellitus.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2556-2558
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• 1998

2-D microwell arrays for micro ELISA (Enzyme-Linked Immuno Solvent Assay) system were fabricated using micromachining technology. The materials for the bottom plate, top plate and sidewall of the microwell were used a #7740 glass, gold and silicon respectively considering bio-compatibility and easy fabrication. Cylindrical or groove shape microwells, which have about $100{\mu}m$ depth and $50{\sim}500{\mu}m$ diameter or width, were arrayed. The fabricated microwell array can be applied to the essential part of a biochip when surface modification is made to immobilize cells or biomolecules on the microwell bottom.

• Interdisciplinary Bio Central
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• 제2권2호
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• pp.1.1-1.8
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• 2010

Microdevices have been used as effective experimental tools for the rapid and multiplexed analysis of individual cells in single-cell assays. Technological advances for miniaturizing such systems and the optimization of delicate controls in micron-sized space homing cells have motivated many researchers from diverse fields (e.g., cancer research, stem cell research, therapeutic agent development, etc.) to employ microtools in their scientific research. Microtools allow high-throughput, multiplexed analysis of single cells, and they are not limited by the lack of large samples. These characteristics may significantly benefit the study of immune cells, where the number of cells available for testing is usually limited. In this review, I present an overview of several microtools that are currently available for single-cell analyses in two popular formats: microarrays and microfluidic microdevices. Then, I discuss the potential to study human immunology on the single-cell level, and I highlight several recent examples of immunoassays performed with single-cell microdevice assays. Finally, I discuss the outlook for the development of optimized assay platforms to study human immune cells. The development and application of microdevices for studies on single immune cells presents novel opportunities for the qualitative and quantitative characterization of immune cells and may lead to a comprehensive understanding of fundamental aspects of human immunology.

• 소성∙가공
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• 제15권9호
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• pp.667-672
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• 2006

Agglutination is one of the most commonly employed reactions in clinical diagnosis. In this paper, we have designed and fabricated nickel mold insert for injection molding of a microfluidic lab-on-a-chip for the purpose of the efficient detection of agglutination. In the presented microfluidic lab-on-a-chip, two inlets for sample blood and reagent, flow guiding microchannels, improved serpentine laminating micromixer(ISLM) and reaction microwells are fully integrated. The ISLM, recently developed by our group, can highly improve mixing of the sample blood and reagent in the microchannel, thereby enhancing reaction of agglutinogens and agglutinins. The reaction microwell was designed to contain large volume of about $25{\mu}l$ of the mixture of sample blood and reagent. The result of agglutination in the reaction microwell could be determined by means of the level of the light transmission. To achieve the cost-effectiveness, the microfluidic lab-on-a-chip was realized by the injection molding of COC(cyclic olefin copolymer) and thermal bonding of two injection molded COC substrates. To define microfeatures in the microfluidic lab-on-a-chip precisely, the nickel mold inserts of lab-on-a-chip for the injection molding were fabricated by combining the UV photolithography with a negative photoresist SU-8 and the nickel electroplating process. The microfluidic lab-on-a-chip developed in this study could be applied to various clinical diagnosis based on agglutination.

• Korean Chemical Engineering Research
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• 제54권2호
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• pp.223-228
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• 2016

본 논문은 PDMS을 기반으로 한 미세접촉인쇄법을 사용하여 보다 효율적으로 지방세포를 선택적으로 배양접시에 부착시켰으며 패터닝 된 배양접시에서 지방세포가 빠르게 지방분화를 가능하게 하였다. PDMS을 이용한 선택적 표면 처리 방법은 기존의 세포칩 제작과 달리 소량의 유기용매사용, 저가의 장비 사용, 또한 효율적으로 특정 지역 안에서 지방세포를 고정화하고 성장시킬 수 있으며 이를 통해 지방세포의 생리학적 상태를 손쉽게 관찰할 수 있는 분석 기술로 활용된다. 이렇게 구성된 지방세포칩 위에 대표적인 비만 억제제 약물인 Orlistat을 $0.2{\mu}M{\sim}5.0{\mu}M$ 농도로 처리하였을 때 대조군에 비하여 최대 26.5%의 억제 효과가 나타남을 확인하였다. 따라서, 본 논문에서 제안하는 방법을 통하여 다양한 비만 억제제 약물 탐색을 위한 세포칩으로 활용이 가능할 것으로 기대된다.

• Clinical and Experimental Reproductive Medicine
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• 제50권4호
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• pp.244-252
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• 2023

Objective: We evaluated the efficacy of the newly developed optimized in vitro culture (OIVC) dish for cultivating preimplantation mouse embryos. This dish minimizes the need for mineral oil and incorporates microwells, providing a stable culture environment and enabling independent monitoring of individual embryos. Methods: Mouse pronuclear (PN) zygotes and two-cell-stage embryos were collected at 18 and 46 hours after human chorionic gonadotropin injection, respectively. These were cultured for 120 hours using potassium simplex optimized medium (KSOM) to reach the blastocyst stage. The embryos were randomly allocated into three groups, each cultured in one of three dishes: a 60-mm culture dish, a microdrop dish, and an OIVC dish that we developed. Results: The OIVC dish effectively maintained the osmolarity of the KSOM culture medium over a 5-day period using only 2 mL of mineral oil. This contrasts with the significant osmolarity increase observed in the 60-mm culture dish. Additionally, the OIVC dish exhibited higher blastulation rates from two-cell embryos (100%) relative to the other dish types. Moreover, blastocysts derived from both PN zygotes and two-cell embryos in the OIVC dish group demonstrated significantly elevated mean cell numbers. Conclusion: Use of the OIVC dish markedly increased the number of cells in blastocysts derived from the in vitro culture of preimplantation mouse embryos. The capacity of this dish to maintain medium osmolarity with minimal mineral oil usage represents a breakthrough that may advance embryo culture techniques for various mammals, including human in vitro fertilization and embryo transfer programs.