• 한국전기전자재료학회논문지
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• 제35권4호
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• pp.342-347
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• 2022

In-situ analyzation and detection of real-time chemical reactions can be a significant part in interpreting the underlying mechanism in very reactive chemical reactions. To do this, first we have designed a microfluidic device (MFD) pattern for observation of synthesis of hierarchical nanostructures based on graphene oxide (GO), conjugating the well-known coupling reaction by which the solution of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)-mediated coupling is enhanced in the presence of n-hydroxysuccinimide (NHS) to make amide bonding, hereafter called as the EDC coupling. Then, we have manufactured microfluidic devices with multiple tens of micrometer-sized channels that can circulate those nanomaterials to be chemically reacted in the channels. These microfluidic devices were made by negative photo lithography and soft lithography. We showed the possibility of using Raman spectroscopy to reveal the basic mechanism of the energy storage applications.

• 대한의용생체공학회:의공학회지
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• 제30권6호
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• pp.453-460
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• 2009

In this review paper, concepts in optofluidics are applied to an advanced manufacturing technology based on self-assembled microparts. The "optical" aspect of optofluidics will be described in the context of photolithography, and the "fluidic" aspect will be discussed in the context of self-assembly. First, optofluidic maskless lithography will be introduced as a dynamic fabrication method to generate microparticles in microfluidic channels. Next, the history and application of optofluidic lithography will be presented.

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2004년도 춘계총회 및 연구발표회 초록집
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• pp.31.3-31.3
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• 2004

• Molecular & Cellular Toxicology
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• 제2권4호
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• pp.279-284
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• 2006

This paper describes the fabrication methods of a carbon nanotube (CNT) filter and a microdialysis chip. A CNT filter can help perform dialysis on a microfluidic chip. In this study, a membrane type of a CNT filter is fabricated and located in a microfluidic chip. The filter plays a role of a dialysis membrane in a microfluidic chip. In the fabrication process of a CNT filter, individual CNTs are entangled each other by amide bonding that is catalyzed by 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The chemically treated CNTs are shaped to form a CNT filter using a PDMS film-mold and vacuum filtering. Then, the CNT filter is sandwiched between PDMS substrates, and they are bonded together using a thin layer of PDMS prepolymer as adhesive. The PDMS substrates are fabricated to have a microchannel by standard photo-lithography technique.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2006년도 제31회 학술논문발표회 초록집
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• pp.45-45
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• 2006

• 한국세라믹학회지
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• 제45권11호
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• pp.739-743
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• 2008

Microfluidic device can be applied in a wide range of chemical and biological technology. In this paper, ceramic-based T-type passive mixers for microfluidic applications were fabricated by LTCC process combined with thick film photolithography. The base ceramic material in thick film was amorphous cordierite $((Mg,Ca)_2Al_4Si_5O_{18})$ and photoimageable polymers were added to give a photosensitivity. Two types of passive mixer, which showed the channel width of 1.0 mm and $200{\mu}m$, respectively, were designed considering mixing efficiency in the channel and their microfluidic properties were discussed in detail.

• 청정기술
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• 제25권4호
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• pp.283-288
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• 2019

단분산성 마이크로입자는 약물캡슐화 및 전달을 위한 다양한 응용분야에서 사용되고 있다. 미세유체장치는 매우 균일한 액적을 생산할 수 있는 중요한 장치이며 이 액적은 단분산성 마이크로입자를 생성할 수 있는 중요한 템플레이트(template)로의 역할을 한다. 미세유체장치는 마이크론 크기의 채널로 구성되어 표면장력과 점성력 간의 균형을 정교하게 조절할 수 있으며, 이는 단분산성 액적을 형성하는 필수적인 기술 중의 하나이다. 본 연구는 유동집적채널 기반의 미세유체장치에서 매우 균일한 polycaprolactone (PCL) 생분해성 고분자 입자를 제조하는 방법을 제안한다. 유동집적채널 기반의 미세유체장치는 polydimethylsiloxane (PDMS) 기반의 소프트리소그래피(soft-lithography) 방법을 통해 제작된다. 액적 생성에서 중요한 요소는 마이크로 액적의 크기와 단분산성을 조절하는 것이다. 이를 위해, 본 연구에서는 이 미세유체장치에서 오일용액 분산상과 수용액 연속상의 부피유속을 제어하여 단분산성 액적 형성 조건을 최적화하였다. 그 결과 균일한 액적을 형성할 수 있는 dripping 영역에 대한 최척화된 유속조건을 확인하였다. 그런 다음, 마이크로입자를 생성하기 위해 PCL 고분자를 포함한 액적을 장치에서 형성한 후 용매의 증발에 의해 입자화 하였다. 입자의 크기는 부피유속과 미세유체채널의 크기에 의해 조절되며 입자의 단분산도는 변동계수(coefficient of variation, CV)값이 5% 이하로 제어될 수 있다.

• 한국염색가공학회지
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• 제20권1호
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• pp.8-15
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• 2008

We presented the modified decal-transfer lithography (DTL) and light stamping lithography (LSL) as new powerful methods to generate patterns of poly(dimethylsiloxane) (PDMS) on the substrate. The microstructures of PDMS fabricated by covalent binding between PDMS and substrate had played as barrier to locally control wettability. The transfer mechanism of PDMS is cohesive mechanical failure (CMF) in DTL method. In the LSL method, the features of patterned PDMS are physically torn and transferred onto a substrate via UV-induced surface reaction that results in bonding between PDMS and substrate. Additionally we have exploited to generate the patterning of rhodamine B and quantum dots (QDs), which was accomplished by hydrophobic interaction between dyes and PDMS micropatterns. The topological analysis of micropatterning of PDMS were performed by atomic force microscopy (AFM), and the patterning of rhodamine B and quantum dots was clearly shown by optical and fluorescence microscope. Furthermore, it could be applied to surface guided flow patterns in microfluidic device because of control of surface wettability. The advantages of these methods are simple process, rapid transfer of PDMS, modulation of surface wettability, and control of various pattern size and shape. It may be applied to the fabrication of chemical sensor, display units, and microfluidic devices.

• 한국세라믹학회지
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• 제43권12호
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• pp.798-804
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• 2006

Co-planar type single chamber solid oxide fuel cell with patterned electrode on a surface of electrolyte has been fabricated by robo-dispensing method and microfluidic lithography. The cells were composed of NiO-GDC-Pd or NiO-SDC cermet anode, $(La_{0.7}Sr_{0.3})_{0.95}MnO_3$ cathode, and yttria stablized zirconia electrolyte. The cell performance at $900^{\circ}C$ was investigated as a function of electrode geometries, such as anode-to-cathode distance, numbers of electrode pairs. Relationship between OCV and I-V characteristics at the optimized operation condition was also studied by DC source meter under the mixed gas condition of methane, air, and nitrogen. An increase of anode-facing-cathode area leads to lower OCV due to intermixing between product gases of anode and cathode, which in turn decreases the oxygen partial pressure difference.

• Molecules and Cells
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• 제45권2호
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• pp.76-83
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• 2022

Neurons-on-a-Chip technology has been developed to provide diverse in vitro neuro-tools to study neuritogenesis, synaptogensis, axon guidance, and network dynamics. The two core enabling technologies are soft-lithography and microelectrode array technology. Soft lithography technology made it possible to fabricate microstamps and microfluidic channel devices with a simple replica molding method in a biological laboratory and innovatively reduced the turn-around time from assay design to chip fabrication, facilitating various experimental designs. To control nerve cell behaviors at the single cell level via chemical cues, surface biofunctionalization methods and micropatterning techniques were developed. Microelectrode chip technology, which provides a functional readout by measuring the electrophysiological signals from individual neurons, has become a popular platform to investigate neural information processing in networks. Due to these key advances, it is possible to study the relationship between the network structure and functions, and they have opened a new era of neurobiology and will become standard tools in the near future.