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DNA Translocation using Nanoporous Membrane
최요셉(Yosep Choi),차미선(Misun Cha),이정훈(Junghoon Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
This paper reports an on-chip nano porous membrane that can separate bio-molecules based on their sizes and its working principles. The nano porous membrane is considered as one of key elements used for the separation of macromolecules. In conventional approaches for bio-molecular separation with nano porous membrane, however, there are many limitations such as difficulty in integrating with a lab on a chip (LOC) device and the lack of precision in separations. In this work anodized alumina oxide (AAO) nano porous membrane was directly fabricated on a microfluidic platform to be integrated with LOC. In addition, atomic layer deposition (ALD) was used to reduce the pore size down to 13 ㎚. Bio-molecular trans-location through the AAO by electrokinetics and the effective pore size due to surface charge were investigated. Our efficient and effective on-chip device successfully demonstrated the separation of aptamer-protein complex from DNA.
DNA-탄소나노튜브 복합체에서의 Watson-Crick 염기쌍 형성 연구
정승원(Seungwon Jung),차미선(Misun Cha),정남조(Namjo Jeong),이정훈(Junghoon Lee) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
It has been known that a single strand DNA wraps around a SWNT by a π-π stacking. Here we demonstrate that such DNA is dissociated from the SWNT by forming a Watson-Crick base pairing with a complementary sequence. The measurement of FET characteristics indicates the shift of electrical property as a result of this “unwrapping” event. We further confirm the suggested process through atomic force microscopy, transmission electron microscopy, and gel electrophoresis.
최준규(Jun-kyu Choi),차미선(Misun Cha),전은용(Eunyong Jeon),이정훈(Junghoon Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
We present a highly reliable thin membrane transducer (TMT) ? based chemo-mechanical sensing platform fabricated with conventional MEMS process. This device is suspended with ultra thin silicon nitride membrane (100 ㎚) , lower electrode. The counter electrode is effectively built up on just one wafer. The cavity side of the membrane is coated with thin gold (30 ㎚) for molecular immobilization and reaction. The microfluidic cells and capacitance to digital convertor (CDC) chip are integrated with the sensor. The chemomechanical sensing device opens up a new horizon for molecular detections with innovations such as no labelling, time course data, and compact design. In the principle of the TMT, a specific molecular interaction on an extremely thin and flexible membrane surface causes the deflection of the membrane due to surface stress change which can be measured by a capacitive circuit.
박테리아 자성나노입자-압타머 접합체의 시토크롬 씨 표적화를 통한 세포 생존율 조절
최정인(Jungin Choi),차미선(Misun Cha),이정훈(Junghoon Lee) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
Bacteria magnetic particle (BMP) is one of important candidate for delivering molecules to inside cells. Due to its unique property such as bio-compatiblity, super paramagnetic ability, uniform nano scale size, BMP is used in many areas. In this study, aptamer, which is an oligonucleic acid or a peptide that can bind specifically to the target molecules used for targeting cytochrome C. The specific response of the cell only uptakes BMP and BMP-aptamer conjugate is measured in several ways. Using the information of cell viability, protein concentration, and microscope picture, the effect of the followings can be discovered: magnetic field, BMP, targeted cytochrome C by BMP-aptamer conjugate. Moreover, holding cytochrome C by targeted BMPaptamer conjugate and magnetic field, the specific function of cytochrome C can be also distinguished.
액체 상태에서 SWNT 와 DNA 사이의 전자 상호작용 연구
정승원(Seungwon Jung),차미선(Misun Cha),차문현(Moon-Hyun Cha),김건(Gunn Kim),임지순(Jisoon Ihm),이정훈(Junghoon Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
A field effect transistor (FET) measurement of a single-walled carbon nanotube (SWNT) shows a transition from a metallic one to a p-type semiconductor after helical wrapping of DNA. Water is found to be critical to activate this metal-semiconductor transition in the ssDNA?SWNT hybrid. Raman spectroscopy confirms the same change in electrical behaviors. A band gap can open up in a metallic SWNT with wrapped ssDNA in the presence of water molecules due to charge transfer.
불연속적 강성구배에 의한 생쥐 섬유아세포 움직임에 대한 연구
이수진(Sujin Lee),홍주희(Juhee Hong),차미선(Misun Cha),이정훈(Junghoon Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
A directional cell migration is demonstrated on a discrete rigidity gradient enabled by an array of doublelayered micropillars. This micropillar array has varying diameters (3 ㎛ to 7 ㎛) to accomplish desired rigidity gradient. Fibronectin used as an extra cellular matrix (ECM) is immobilized on pillar “tops”, providing an environment for focal adhesion of cells. In order to avoid the size effect of the ECM on cell reactions, the top diameter of every pillar is maintained identical by fabricating the pillars with double-layered SU-8 mold. NIH3T3 mouse fibroblasts are cultured on the double-layered micro pillar array device, and the motion of the cells is observed by a live imaging instrument. It is found that the rigidity gradient (Δk) needs to be larger than a certain value to initiate a directional and consistent migration. Our device proves that the cells migrate toward stiffer pillars and stay within the stiff region once the directional migration starts.
나노자성입자-항체 복합체를 이용한 세포 내 염색체 위치 제어
홍주희(Juhee Hong),Prashant Purwar,차미선(Misun Cha),이정훈(Junhoon Lee) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10
Recently, nanotechnology has been developed to a stage that makes it possible to produce, characterize, and specifically tailor the functional properties of the MNPs for biological application. This has led to various opportunities such as improving the quality of magnetic resonance imaging, hyperthermic treatment for malignant cells, drug delivery, immunoassay, and biomolecules separation. Specially, bacterial magnetic nanoparticle (BMP) has been played a role in a biomedical application. BMP has useful qualities of dispersibility and facilitative functionalization since they covered with a lipid membrane. In most studies, BMPs were generally used as a carrier which was immobilized with the specific targeting biomolecules. Thus, manipulation of biomolecules and organelles in a cell using BMP has been less developed. Here, we demonstrate the manipulation of chromosomes conjugated with BMP-antibodies complexes in a live mouse oocyte cell using the external magnetic field.