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   Cell separation using non-invasive dielectrophoresis

         우수 미세조류로의 개량을 위한 유전영동 기반의 cell separation system 개발.


         [ Developing a high efficient microalgae strain using mutant induction and non-invasive separation using a microfluidic device using dielectrophoresis. ]




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Colormetric Biosensing using Photonic Crystals
      
         Qdot-aptamer beacon과 광신호 증폭을 위한 3차원 광결정 구조를 이용하여 influenza virus를 10분 내외의 빠른 시간 안에 일반 CCD 카메라를 활용하여
        검출할 수 있는 고감도 바이러스 센서 개발.






                        [ Real-time visualization of influenza virus using Qdot-aptamer beacon and 3D photonic crystals for enhancement of fluorescent signal. ]




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 Smart Contact lens
 
       녹내장 치료 및 안압측정이 가능한 Smart Contact lens.


                             [ Schematic diagram representing the smart contact lens embedding a colorimetric pressure sensor for monitoring glaucoma. ]



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High Current Ionic Diode Using Nanochannel Network Membrane

 

A high current ionic diode is achieved using an asymmetric nanochannel network membrane (NCNM) constructed by soft lithography and in situ self-assembly of nanoparticles with uniform surface charge. The asymmetric NCNM exhibits high rectified currents without losing a rectification ratio because of its ionic selectivity gradient and differentiated electrical conductance. Asymmetric ionic transport is analyzed with diode-like I-V curves and visualized via fluorescent dyes, which is closely correlated with ionic selectivity and ion distribution according to variation of NCNM geometries.

Figure.1

[(a) Schematic diagram for the high current ionic diode based on asymmetric nanochannel networks membrane (NCNM).]

[(b) Asymmetric cation/anion concentration in the proposed device at the equilibrium and its change right after the external electric fields (forward/reverse bias) are applied.]

[(c) Top view and (d) SEM image (a cross-section view in the direction of A-A′) of the proposed system fabricated by soft lithography and homogeneously charged nanoparticle assembly.Schematic diagram representing the fabrication steps for nanoporous hydrogel photonic crystal structures]

 

 

Figure.2

[(a) Sequential fluorescence images when the mixed fluorescent dyes in 1 mM KCl solution were introduced into deep channel B for 10 min.]

[(b) The high red intensity (indicating high ion selectivity) in the tip region was preserved after the same mixed fluorescent solution was injected into both deep channels.]

  

 

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  Paper-based energy harvesting from salinity gradients

 

Paper-based microfluidic devices have many advantages such as low cost, flexibility, light weight and easy disposability. In this study, environment-friendly and flexible paper-based energy harvesting with a simple configuration is demonstrated by using the principle of reverse electrodialysis (RED). RED is a promising clean energy generation method, which converts Gibbs free energy into electricity by salinity gradients without discharging any pollutants. The specification of the research are as follows:

 

[(a) Selective cation migration by diffusion through the ion selective (Nafion) membrane interconnected with the two channels.]

[(b) Schematic illustration of the cross sectional view of the proposed RED device.]

[(c) Exploded diagram and corresponding photos of each layer in the paper-based RED device.]

[(d) Photos of the fabricated paper-based RED device.]

 

 
 

  3D nanochannel networks constructed by spatially controlled nanoparticle assembly

 

The nano-interstices between these assembled nanoparticles serve as the nanopores of ion-selective membranes with equivalent pore size. Its inherent characteristics (compared with the conventional one-dimensional nanochannels) are a high ionic flux and a low fluidic resistance because these nanopore

clusters have a role as collective three-dimensional nanochannel networks, which result in a highly efficient performance beneficial for various applications

The specification of the research are as follows:

 

 

 

       

[ (a) Schematic illustration of the proposed microplatform and the working principle of the ICP phenomenon ]

 

[ (b) Fabrication process for the in situ formation of nanochannel networks using the self-assembly of nanoparticles within the PDMS channel ]

 

 

 
 

  Tunable reverse electrodialysis microplatform

 

Chemical concentration gradients are promising energy resources to power micro/nanodevices sustainably without discharging any pollutants. In this paper, an efficient microplatform based on reverse electrodialysis, which enables high ionic flux through three dimensional nanochannel networks for high power energy generation, is demonstrated. Highly effective cation-selective nanochannel networks are realized between two microfluidic channels with geometrically controlled in situ self-assembled nanoparticles in a cost-effective and simple way. The specification of the research are as follows:

 

 

 

       [ (a) Cation migration by diffusion across the nanochannel network formed with the self-assembled nanoparticles driven by concentration gradient ]

 [(b) Schematic illustration of the cross sectional view in the direction of A–A′ (left) and B–B′ (right) ]

[ (c) SEM images of the fabricated device  at a cross sectional view in the direction of A–A′ (left) and its enlarged image at the interface

between the window of the shallow channel and the side wall of the deep channel (right). ]

 

 
 

  nanoporous hydrogel photonic crystals

 

Photonic crystal (PC) based biosensors have been given attention because of their obvious advantages such as sensitivity, simple and low-cost realization. Many kinds of PC based biosensors have been reported, for example, holographic PCs, porous silicon PCs, PC fibers and colloidal crystal film. Among these PC based sensors, we have interested on an inverse opal structure film in order to apply to specific and label-free detection of proteins. The specification of the research are as follows:

 

 

       

[Schematic diagram representing the fabrication steps for nanoporous hydrogel photonic crystal structures]

 

 

  

[Scheme of the process of protein A immobilization and IgG binding]

 

 

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  Intelligent theragnostic bacteria based biomedical mocrorobot

 

The final purpose of this research is to develop a bacteria based microrobot (bacteriobot) using various characteristics of gene modified bacteria, such as locomotion, targeting to cancer, and fluorescence. To achieve the final purpose, the evaluation about cancer targeting of bacteria and the development of microplatform for studying bacterial chemotaxis about cancer cell or chemical signal induced tumor are essential techniques. The specification of the research are as follows:

  ·  Development of microplatform for studying in vitro bacterial chemotaxis

    - Multiple chemical gradients generation (more than 2 kinds)

    - Modeling and analysis of bacterial chemotaxis  

  ·  Evaluation and confirmation about cancer targeting of bacteria  

     - Development of in vitro co-culture system for cancer and bacteria

     - Evaluation about cancer targeting of bacteria using the developed system

 

       

[Conceptual images for bacteriobot, more detail info is available at http://www.bacteriobot.com]

 

 

  · Stable multiple chemical gradients generation

 

[A schematic view of the configuration and principle idea]

 

 

[Microplatform for generation of multiple chemical gradients]           

    

      

             [Dynamic positioning control of bacteria]

       

          

           [Preferential chemotaxis assay for bacteria]

   

 

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  Bioogically inspired colorimetric nanobiosensor

   

The purpose of this study is the design and fabrication of label-free immunosensors based on 3D photonic crystals detectable with color change in real time. The proposed sensor will have advantages of the sensors such as shortening of analysis time and cost, enhancement of sensitivity and selectivity, achievement of mobility, so that any body can use it easily by observing the color change. Moreover, the sensor can be operated without any external energy such as batteries, and does not require the electrical wire for supply of energy, so that it is eco-friendly technology and can be installed in clothing, building, and subway and show the various applications.

  · Biologically inspired humidity sensor based on three-dimensional photonic crystals

 

 

 

  · Label-free colorimentric biosensor

   

  

[IgG antibody detection using PC based colorimetric sensor]

 

 

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  Cell separation using non-invasive dielectrophoresis

 

  · Advantages of dielectrophoresis [Y. Huang et al., 2002]

    - Controllability

    - Ease of application to automation

    - Noninvasive (No biochemical labels, probes or tag required)

    - Diverse Applications

 

  · Cell separations using advanced DEP devices with 3-D asymmetric electrodes

 

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[77±5% purity of MCF7 cells in the outlet for MCF7 cells was obtained]

 

  · High throughput separation using gradient traveling wave dielectrophoresis

 

 

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  Biohybrid microsystems

 

  · Biohybrid system

- A biohybrid system is a miniaturised system which combines biological cells with technical microsystems. Using this combination, new assay technologies can be developed, which allow cell-based tests with a higher sensitivity and reproducibility, tests on the single cell level as well as long-term-analyses of the cell behaviour after application of relevant concentrations of active agents. [Fraunhofer Institute]

- Consists of biological organisms and artificial systems to use  the both benefit from the two systems

 

  · Development of hybrid biopolymer actuators

- Our goal is developing a muscle powered hybrid biopolymer actuator based on cardiomyocytes: Glucose -->ATP -->Mechanical Energy

- Biohybrid microcantilevers can be also used as a quantitative sensor for measurement of contractile force of cardiomyocytes

 

  · Development of a hybrid cell robot

 

    

[Biohybrid microcantilevers and cell robot]

 

  · Micro pumping with cardiomyocyte–polymer hybrid

 

 

 

  · MEMS-based power generation system using contractile force generated by self-organized cardiomyocytes

 

 

 

   

 

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  Microengineered platforms for cell mechanobiology

 

  · Biomechanical environment of cells and tissues

- Cells experience various mechanical stimuli in a human body, particularly important in the cardiovascular and musculoskeletal systems. To permit human locomotion, tensile muscular forces and compressive loads act on cartilage and bones through tendons to move joints. In blood vessels, cells are continuously subjected to shear and hydrostatic stress from blood flow

 

      

[The various biomechanical environment of cells and tissues in a human body. Mechanical forces can play a critical role in the regulation of cell signaling and function undernormal physiological conditions on the microscale]

 

 

[Measurement of Single-Cell Deformability Using Impedance Analysis on Microfluidic Chip]

 


NanoBiosystems and Manipulation Laboratory
Department of Mechanical Engineering
Sogang University
Sinsudong, Mapogu, Seoul, Korea 121-742, Tel +82-2-701-7075