• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.736-736
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• 2003

• 기계저널
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• 제54권9호
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• pp.28-30
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• 2014

이 글은 기존 종양세포 배양법과 항암제 내성 기전 연구에서의 문제점을 극복하기 위한 새로운 방법으로서 microfluidic device를 사용하려는 시도에 관한 것이다.

• 대한의용생체공학회:의공학회지
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• 제28권2호
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• pp.244-249
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• 2007

Fluidic conditions for the separation of phases were surveyed in a microfluidic aqueous two-phase extraction system. The infusion ratio between polyethylene glycol (PEG) and dextran solution defines the concentrations of each polymer in micro-channel, which determine the phase-separation. The appropriate ratio between PEG (M.W. 8000, 10%, w/v) and dextran T500 (M.W. 500000, 5%, w/v) in order to perform the separation of phases of both polymers was observed as changing the mixed ratio of both polymers. Based on the fluidic conditions, stable two-phase solutions were obtained within 4% to 8% and 3% to 1% of PEG and dextran, respectively. In addition, the characteristics of the two-phase were discussed. The separation technique studied in the paper can be applied for the implementation of a lab-on-a chip which can detect various biological entities such cells, bacterium, and virus in an integrated manner using built in a biosensor inside the chip.

• Bulletin of the Korean Chemical Society
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• 제34권10호
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• pp.2921-2924
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• 2013

Immunoliposomes (antibody-conjugated liposomes) are highly useful as both a drug carrier in drug delivery and as a reporting probe in immunodiagnostics. However, antibody conjugation is lengthy and cumbersome, because this includes several steps such as derivatization of the antibody, conjugation of the derivatized antibody to liposomes, and separation of the unbound antibodies from immunoliposomes. Recently, liposome preparation steps have simplified by using microfluidic devices (${\mu}FDs$) where liposomes are formed when a stream of lipids in solvent is hydrodynamically focused between two oblique buffer streams in a microchannel. Herein, we report a simple method for the production of immunoliposomes (rabbit IgG-conjugated liposomes) using microvalve-controlled ${\mu}FD$. The presence of antibody on the liposome was verified by observing the binding of immunoliposomes to rabbit IgG on the surface. The results suggest that immunoliposomes can be easily prepared through sequential mixing of antibody, conjugation reagents, preformed liposomes using microvalve-controlled ${\mu}FD$.

• 한국융합학회논문지
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• 제12권8호
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• pp.179-186
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• 2021

국내 승인된 코로나-19 백신 중, mRNA 플랫폼 기반 백신의 제조공정을 중심으로 살펴보았다. 제조공정은 크게 DNA 주형 제조공정, mRNA 전사공정, 나노에멀젼화 공정, 제형화, 그리고 완제공정으로 이루어져 있다. 이 공정들은 여러 제약사 및 위탁생산회사와 협업으로 진행되고 있다. 이 중 핵심공정인 나노에멀젼화 공정은 mRNA 보호역할을 위해 지질 성분들이 필요하며, 혼합공정에는 microfluidic device를 활용하는 것으로 알려져 있다. 나노에멀젼화 공정 기술은 향후 다양한 의약품 개발에 자극제 역할을 할 것으로 기대된다.

• Genomics & Informatics
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• 제19권1호
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• pp.2.1-2.10
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• 2021

BRAF inhibitors (e.g., vemurafenib) are widely used to treat metastatic melanoma with the BRAF V600E mutation. The initial response is often dramatic, but treatment resistance leads to disease progression in the majority of cases. Although secondary mutations in the mitogen-activated protein kinase signaling pathway are known to be responsible for this phenomenon, the molecular mechanisms governing acquired resistance are not known in more than half of patients. Here we report a genome- and transcriptome-wide study investigating the molecular mechanisms of acquired resistance to BRAF inhibitors. A microfluidic chip with a concentration gradient of vemurafenib was utilized to rapidly obtain therapy-resistant clones from two melanoma cell lines with the BRAF V600E mutation (A375 and SK-MEL-28). Exome and transcriptome data were produced from 13 resistant clones and analyzed to identify secondary mutations and gene expression changes. Various mechanisms, including phenotype switching and metabolic reprogramming, have been determined to contribute to resistance development differently for each clone. The roles of microphthalmia-associated transcription factor, the master transcription factor in melanocyte differentiation/dedifferentiation, were highlighted in terms of phenotype switching. Our study provides an omics-based comprehensive overview of the molecular mechanisms governing acquired resistance to BRAF inhibitor therapy.

• Korean Chemical Engineering Research
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• 제56권5호
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• pp.761-766
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• 2018

액적-기반 미세유체장치는 물질 합성 및 초고속 대용량 스크리닝 등 다양한 응용분야에서 변형 가능한 새로운 접근법을 이끌어 냈다. 그러나 단일의 액적생성기를 이용한 액적의 생성 속도가 매우 낮기 때문에 이를 상용화 하기 위해서는 생산속도를 높이기 위한 노력이 필요하다. 본 연구는 단일의 유동-집속 생성기를 병렬로 연결하여 단분산성 액적의 생성 속도를 높이는 방법에 관한 것이다. 이러한 액적생성기를 갖는 미세유체장치를 제작하기 위해 본 연구에서는 양면 임프린팅 방법을 이용하여 단층 엘라스토머 조각에3차원의 마이크로 채널을 갖는 3D 모놀리식 탄성중합체 장치(monolithic elastomer device, 3D MED)를 제작 할 수 있다. 이렇게 제작된 8개의 액적생성기가 연결된 3D MED를 이용하여 연속상과 분산상의 유체를 조절하여 단분산성 액적의 형성속도가 향상되었음을 증명하였다. 따라서 본 미세유체시스템을 사용하여 다양한 재료 또는 세포들을 함유하는 단분산성 액적을 형성하여 마이크로입자 제조 및 스크리닝 시스템과 같은 넓은 분야에 활용될 수 있을 것으로 기대된다.

• Korean Chemical Engineering Research
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• 제48권5호
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• pp.545-555
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• 2010

최근 액적 기반의 미세유체 시스템은 물리, 화학, 생물학등의 기초과학과 재료과학 분야까지 매우 폭넓게 활용되고 각광받고 있는 기술분야이다. 본 총설은 액적기반 미세유체 시스템의 미세유체 반응기 제작 기술, 액적 형성 원리, 액적 혼합 및 제어, 그리고 새로운 기능성 재료의 합성등의 폭넓은 응용분야에 관해 자세하게 소개하고자 한다. 더불어 액적기반 미세유체 시스템의 가장 큰 장점인 입자의 크기 조절 방법, 형태, 모양 및 구조의 제어 기술에 관해 논의하고자 한다.

• 센서학회지
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• 제15권3호
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• pp.158-163
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• 2006

This paper reports a novel immunoassay method using superparamagnetic nanoparticles and an enhanced magnetic field gradient for the detection of protein in a microfluidic device. We use superparamagnetic nanoparticles as a label and fluorescent polystyrene beads as a solid support. Based on this platform, magnetic force-based microfluidic immunoassay is successfully applied to analyze the concentration of IgG as model analytes. In addition, we present ferromagnetic microstructure connected with a permanent magnet to increase magnetic flux density gradient (dB/dx, ${\sim}10^{4}$ T/m), which makes limit of detection reduced. The detection limit is reduced to about 1 pg/mL.

• 한국정밀공학회지
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• 제31권5호
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• pp.441-449
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• 2014

Thermoplastic fusion bonding is widely used to seal polymer microfluidic devices and optimal bonding protocol is required to obtain a successful bonding, strong bonding force without channel deformation. Besides, UV modification of the PMMA (poly-methyl methacrylate) is commonly used for chemical or biological application before the bonding process. However, study of thermal bonding for the UV modified PMMA was not reported yet. Unlike pristine PMMA, the optimal bonding parameters of the UV modified PMMA were $103^{\circ}C$, 71 kPa, and 35 minutes. A very low aspect ratio micro channel (AR=1:100, $20{\mu}m$ depth and $2000{\mu}m$ width) was successfully bonded (over 95%, n>100). Moreover, thermal bonding of multi stack PMMA chips was successfully demonstrated in this study. The results may applicable to fabricate a complex 3 dimensional microchannel networks.