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Washing and Enrichment of Micro-Particles Encapsulated in Droplets
Researchers developed microfluidic technology for the washing and enrichment of in-droplet micro-particles. They presented the technology using a microfluidic chip based on surface acoustic wave (SAW)-driven acoustic radiation force (ARF).
The team demonstrated the first instance of acoustic in-droplet micro-particle washing with a particle recovery rate of approximately 90 percent. They further extended the applicability of the proposed method to in-droplet particle enrichment with the unprecedented abilities to increase the in-droplet particle quantity and exchange the droplet dispersed phase.
This proposed method enabled on-chip, label-free, continuous, and selective in-droplet micro-particle manipulation. The team demonstrated the first instance of in-droplet micro-particle washing between two types of alternating droplets in a simple microchannel, proving that the method can increase the particle quantity, which has not been achieved by previously reported methods.
The study aimed to develop an in-droplet micro-particle washing and enrichment method based on SAW-driven ARF. When a droplet containing particles is exposed to an acoustic field, both the droplet and suspended particles experience ARF arising from inhomogeneous wave scattering at the liquid-liquid and liquid-solid interfaces. Unlike previous in-droplet particle manipulation methods, this method allows simultaneous and precise control over the droplets and suspended particles. Moreover, the proposed acoustic method does not require labelled particles, such as magnetic particles, and employs a simple microchannel geometry.
Microfluidic sample washing has emerged as an alternative to centrifugation because the limitations of centrifugation-based washing methods can be addressed using continuous washing processes. It also has considerable potential and importance in a variety of applications such as single-cell/particle assays, high-throughput screening of rare samples, and cell culture medium exchange.
Compared to continuous flow-based microfluidic methods, droplet-based microfluidic sample washing has been rarely explored due to technological difficulties. On-chip, in-droplet sample washing requires sample transfer across the droplet interface composed of two immiscible fluids. This process involves simultaneous and precise control over the encapsulated sample and droplet interface during the medium exchange of the in-droplet sample.
Sample encapsulation within individual microscale droplets offers isolated microenvironments for the samples. Experimental uncertainties due to cross-contamination and Taylor dispersion between multiple reagents can be reduced in droplet-based microfluidics.
This is the first research achievement made by the Acousto-Microfluidics Research Center for Next-Generation Healthcare, the cross-generation collaborative lab KAIST opened in May. This novel approach pairs senior and junior faculty members for sustaining the research legacy even after the senior researcher retires. The research center, which paired Chair Professor Hyung Jin Sung and Professors Hyoungsoo Kim and Yeunwoo Cho, made a breakthrough in microfluidics along with PhD candidate Jinsoo Park. The study was featured as the cover of Lab on a Chip published by Royal Society of Chemistry.
Jinsoo Park, first author of the study, believes this technology will may serve as an in-droplet sample preparation platform with in-line integration of other droplet microfluidic components. Chair Professor Sung said, “The proposed acoustic method will offer new perspectives on sample washing and enrichment by performing the operation in microscale droplets.”
Figure 1. (a) A microfluidic device for in-droplet micro-particle washing and enrichment; (b) alternatingly produced droplets of two kinds at a double T-junction; (c) a droplet and encapsulated micro-particles exposed to surface acoustic wave-driven acoustic radiation force; (d-h) sequential processes of in-droplet micro-particle washing and enrichment operation.
2018.10.19 View 8075 -
Effective Drug Delivery to Heart with Tannic Acid
(Professor Haeshin Lee from the Department of Chemistry) Typical methods of drug delivery to the heart require surgical procedures involving incisions in the chest wall and bones. To efficiently treat cardiovascular and related vascular diseases without surgery, a KAIST research team developed a heart-targeting drug delivery technology using tannin acid via intravenous systemic injection. This method can be applied to the development of a variety of new protein-based drugs.
Cardiovascular-circulatory disease is currently the second leading cause of death in Korea. A typical example of this disease is myocardial infarction caused by poor oxygen and nutrient supply due to narrowed coronary arteries and poor blood flow to the heart.
Although there have been numerous research projects to develop chemotherapeutic drugs and therapeutic proteins, clinics still rely on surgical procedures. Drug delivery can be an alternative, but it is quite challenging because ceaseless dynamic cycles of the heart and massive exchanges of blood mean administered therapeutics do not stay inside the heart very long.
Professor Haeshin Lee from the Department of Chemistry and his team employed tannic acid (TA), which is known for giving bitter taste to wines. It is one of the most abundant polyphenols and can be easily found in plants, such as fruits, vegetables, cacao, and others. TA has also been used as a multifunctional coating molecule.
Using these properties of TA, the team complexed protein and peptide therapeutics with tannic acid and succeeded in targeting protein and peptide therapeutics to the heart. TA, coated on the surface of a granulated protein complex, helps maintain cardiac function because it adheres to extracellular matrices, elastin, and collagens in heart tissues allowing the protein to stay attached to the heart tissue for a longer period.
The team confirmed that these Tannic-acid-modified proteins stay in blood vessels five days longer than with protein-only injections. Additionally they found that TA-protein complexes do not show any cardiac toxicity and do not cause noticeable pathology.
The team has been continuously developing biomaterials for medical applications by testing various polyphenolic materials that feature adhesive and coating properties, including tannic acid. They have injected a mixture of TA and fibroblast growth factors (FGF) into animal models with myocardial infarctions. After four weeks, they confirmed that the infarction was reduced and the left ventricular pressure and cardiac output were almost normalized.
Professor Lee said, “Although there have been numerous drugs related to heart disease, so far there has not been efficient drug delivery to the heart so this technology will be able to reformulate existing drugs into new and more efficient drugs.”
This research, jointly led by Dr. Ki-Suk Kim from the Predictive Model Research Center, was published in Nature Biomedical Engineering on April 30 ( http://www.nature.com/articles/s41551-018-0227-9 ).
Figure 1. Schematic for the heart-targeting mechanism of TANNylated protein nanocomplexes: (1) size-dependent permeation, (2) phenolic (that is, TA), and (3) internalization by internalization by myoblasts
Figure 2. Effect of TA based protein complexes on cardiac cell transport efficiency and viral gene expression efficiency and therapeutic function in animal models with myocardial infarction
2018.09.18 View 5628 -
Participation in the 2018 Bio-Digital City Workshop in Paris
(A student make a presentatiion during the Bio-Digital City Workshop in Paris last month.)
KAIST students explored ideas for developing future cities during the 2018 Bio-Digital City Workshop held in Paris last month.
This international workshop hosted by Cité des Sciences et de l'Industrie was held under the theme “Biomimicry, Digital City and Big Data.” During the workshop from July 10 to July 20, students teamed up with French counterparts to develop innovative urban design ideas. Cité des Sciences et de l'Industrie is the largest science museum in Europe and is operated by Universcience, a specialized institute of science and technology in France.
Professor Seongju Chang from the Department of Civil and Environmental Engineering and Professor Jihyun Lee of the Graduate School of Culture Technology Students led the students group.
Participants presented their ideas and findings on new urban solutions that combine biomimetic systems and digital technology. Each student group analyzed a special natural ecosystem such as sand dunes, jellyfish communities, or mangrove forests and conducted research to extract algorithms for constructing sustainable urban building complexes based on the results. The extracted algorithm was used to conceive a sustainable building complex forming a part of the urban environment by applying it to the actual Parisian city segment given as the virtual site for the workshop.
Students from diverse background in both countries participated in this convergence workshop. KAIST students included Ph.D. candidate Hyung Min Cho, undergraduates Min-Woo Jeong, Seung-Hwan Cha, and Sang-Jun Park from the Department of Civil and Environmental Engineering, undergraduate Kyeong-Keun Seo from the Department of Materials Science and Engineering, JiWhan Jeong (Master’s course) from the Department of Industrial and Systems Engineering, Ph.D. candidate Bo-Yoon Zang from the Graduate School of Culture Technology. They teamed up with French students from diverse backgrounds, including Design/Science, Visual Design, Geography, Computer Science and Humanities and Social Science.
This workshop will serve as another opportunity to expand academic and human exchange efforts in the domain of smart and sustainable cities with Europe in the future as the first international cooperation activity of KAIST and the Paris La Villette Science Museum.
Professor Seong-Ju Chang who led the research group said, "We will continue to establish a cooperative relationship between KAIST and the European scientific community. This workshop is a good opportunity to demonstrate the competence of KAIST students and their scientific and technological excellence on the international stage.”
2018.08.01 View 11582 -
KAIST Partners with Taiwan for PhD Scholarship Program
(President Shin, Taiwanese Acting Minister of Education Yao, Deputy Director General Chang at the Ministry of Education pose after signing the MOU.(from left))
President Sung-Chul Shin signed an MOU with the Ministry of Education in Taiwan for the Taiwanese PhD scholarship program. The signing was made between President Shin and Dr. Yao Leehter, acting Minister of Education in Taiwan, on June 27.
The Taiwanese Ministry of Education is signing MOUs with prestigious universities around the world to encourage its students to pursue study abroad opportunities at top schools. According to the MOU, Taiwanese PhD candidates will be able to use KAIST scholarships for their tuition fees, while the Taiwanese government will provide a stipend and living costs for four years from next September.
KAIST became the 14th university to sign this MOU, joining a group of top universities that includes University of Cambridge, Oxford University, California Institute of Technology, and Columbia University in the US. KAIST is the first institution in Asia to sign the MOU.
Acting Minister Yao said, “KAIST has emerged as a world leading university in less than five decades since its foundation. This remarkable growth led us to partner with KAIST. We hope this will serve as an opportunity to further our partnership in research collaboration as well as students exchanges.”
President Shin appreciated the Taiwanese government’s recognition of KAIST’s global reputation. He said, “We will closely collaborate with the Taiwan government and its universities for transforming educational opportunities to better respond to the Fourth Industrial Revolution.
2018.06.27 View 6153 -
ICISTS 2018: Presence of the Wall, Constraint or Control
A KAIST undergraduates body, ICISTS (International Conference for Integration of Science, Technology and Society) will host the 2018 international conference from July 30 to August 3 at KAIST. Under the theme of “Presence of the Wall: Constraint or Control,” participants will share their opinions on the limits the global world is facing today and look for answers discussing various social issues and technologies. More than 300 students from 60 universities in 15 countries will attend the conference.
Speakers include CEO Sebastien Gendron of TransPod Inc., a Canadian company designing and manufacturing ultra-high-speed transportation technology and vehicles, researcher Sven Kreiss from the Visual Intelligence for Transportation of École Polytechnique Fédérale de Lausanne, Professor Des Freedman from the Department of Media and Communications of Goldsmiths, University of London and political scientist-technologist Wilneida Negrón at the Data & Society Research Institute of Ford Foundation in the US.
The conference will hold programs to facilitate the exchange of ideas among speakers and participants. Participants will make small teams for free discussions to share their ideas and thoughts about issues affecting the human race. Participants will be also assigned a team project in which they must come up with creative ideas based on the lectures. Moreover, they can try new gadgets from companies during the Experience Session.
ICISTS was established in 2005 by undergraduate students from KAIST. The organization holds an international conference every year to explore ways to create harmonization among society, science, and technology. It has grown to become Asia’s largest international student conference.
For learn more and register for the program, please visit http://www.icist.org
2018.05.30 View 6900 -
Blockchain and Cryptocurrency: Between Reality and Virtuality
A workshop on blockchain and cryptocurrency, one of the 4th Industrial Revolution Workshop Series, was held at the KAIST main campus on March 7.
Experts from industry, academia, and research gathered and shared their opinions about blockchain technology, which is currently gaining huge attention along with cryptocurrency.
During the workshop, four KAIST professors and four experts from institutes and business examined the scope on the possibility of blockchain, technology for the Fourth Industrial Revolution.
Moreover, they discussed a variety of issues including mining, wallets, cryptocurrency, information security, smart contracts, and ICOs.
In a previous blockchain tutorial, Professor Yongdae Kim from the School of Electrical Engineering at KAIST and Professor Hyoungshick Kim from Sungkyunkwan University opened up a blockchain tutorial which provided a technical understanding of blockchain, such as the birth of cryptocurrency, algorithm design, and exchange methods.
Professor Jungho Kim, who is in charge of this event, said, “This workshop will broaden the understanding of blockchain, which can provide a foundation for a national growth engine.”
2018.03.07 View 8196 -
Aqueous Storage Device Needs Only 20 Seconds to Go
(from left: PhD candidate Il Woo Ock and Professor Jeung Ku Kang)
A KAIST research team developed a new hybrid energy storage device that can be charged in less than half a minute. It employs aqueous electrolytes instead of flammable organic solvents, so it is both environmentally friendly and safe. It also facilitates a boosting charge with high energy density, which makes it suitable for portable electronic devices.
Professor Jeung Ku Kang and his team from the Graduate School of Energy, Environment, Water, and Sustainability developed this hybrid energy storage with high energy and power densities along over a long cycle life by assembling fibre-like polymer chain anodes and sub-nanoscale metal oxide cathodes on graphene.
Conventional aqueous electrolyte-based energy storage devices have a limitation for boosting charges and high energy density due to low driving voltage and a shortage of anode materials.
Energy storage device capacity is determined by the two electrodes, and the balance between cathode and anode leads to high stability. In general, two electrodes show differences in electrical properties and differ in ion storage mechanism processes, resulting in poor storage and stability from the imbalance.
The research team came up with new structures and materials to facilitate rapid speed in energy exchange on the surfaces of the electrodes and minimize the energy loss between the two electrodes.
The team made anodes with graphene-based polymer chain materials. The web-like structure of graphene leads to a high surface area, thereby allowing higher capacitance.
For cathode materials, the team used metal oxide in sub-nanoscale structures to elevate atom-by-ion redox reactions. This method realized higher energy density and faster energy exchange while minimizing energy loss.
The developed device can be charged within 20 to 30 seconds using a low-power charging system, such as a USB switching charger or a flexible photovoltaic cell. The developed aqueous hybrid energy device shows more than 100-fold higher power density compared to conventional aqueous batteries and can be rapidly recharged. Further, the device showed high stability with its capacity maintained at 100% at a high charge/discharge current.
Professor Kang said, “This eco-friendly technology can be easily manufactured and is highly applicable. In particular, its high capacity and high stability, compared to existing technologies, could contribute to the commercialization of aqueous capacitors. The device can be rapidly charged using a low-power charging system, and thus can be applied to portable electronic device.”
This research, led by a PhD candidate Il Woo Ock, was published in Advanced Energy Materials on January 15.
Figure 1. Switching wearable LED kit with two AHCs in series charged by a flexible photovoltaic cell
Figure 2. Schematic diagram for aqueous hybrid capacitors
Figure 3. TEM images of anode and cathode
2018.02.28 View 12911 -
Professor Hojong Chang Wins the Best Paper Award at ISIITA 2018
Professor Hojong Chang from the KAIST Institute won the best paper award at the International Symposium on Innovation in Information Technology and Application (ISIITA) 2018.
ISIITA is a global networking symposium in which leading researchers in the field of information technology and applications gather to exchange knowledge on technological convergence.
Professor Chang won the prize for his paper, titled ‘A Study on the Measurement of Aptamer in Urine Using SiPM’.
This paper proposes using aptamer to measure and analyze the density of sodium and potassium contained in urine, allowing diseases to be diagnosed in advance.
Professor Chang said, “With a point-of-care test system that facilitates a quick diagnosis without extra processes, such as centrifugation, it is possible to get an early diagnosis and check infection in real time. Through generalizing this crucial technology, we expect to develop adequate technology for enhancing quality of life.
2018.02.12 View 8648 -
CLKIP Bearing Fruit in China
The Chongqing Liangjiang KAIST International Program (CLKIP) is rapidly gaining steam in China. CLKIP, an educational program operated in Chongqing internationally by KAIST since 2015, offers two majors, Electronic Information Engineering and Computer Science and Technology, applying the same curriculum as at KAIST.
To operate the program, KAIST assigns professors from the School of Electrical Engineering and the School of Computing to the program every year. They are in charge of one-third of the major courses, and transfer KAIST’s educational curriculum and know-how.
A total of 13 professors from Chongqing University of Technology (CQUT) have received or are receiving training on advanced education methodologies and technical know-how, including an on and offline integrated learning program, called Education 4.0 and large-scale internet open learning.As CLKIP is gaining in popularity, the number of students for its undergraduate courses keeps increasing, from 66 in 2015 to 172 in 2016 and 200 students in 2017, achieving the student volume for enrollment annually.
CLKIP selected seven exchange undergraduate students and five dual-degree students this fall, and they are currently studying in KAIST for either one semester or one full year.
CLKIP is located in Chongqing, one of the major direct-controlled municipalities and a focal point for notable government projects. The Korea-China industrial zone is also located in this area.
Considering its location, CLKIP is more than just an international programs for educational cooperation. The program will provide opportunities to cooperate with Korean enterprises including Hyundai, SK Hynix, LG Chem and Hankook Tire. While cooperating in research and development as well as technical assistance, KAIST hopes that these enterprises will play a bridging role for KAIST alumni entering the Chinese market.
President Sung-Chul Shin said, “The success of CLKIP shows that KAIST programs for fostering future manpower and developing cutting-edge technologies do work in other countries. Based on this case, KAST will put more effort into transferring our innovative education systems abroad. We are also pushing ahead to establish a joint institute between KAIST and CQUT by 2018, which will become a foundation for facilitating the entry of KAIST’s cutting-edge technologies into the Chinese market.”
“KAIST aims to become an entrepreneurial university that creates value through technology commercialization. In this sense, KAIST plans to transfer advanced technologies to domestic and international companies located in the Liangjiang district,” he added.
2017.12.12 View 11780 -
In Jin Cho Earned the Best Poster Prize at ME Summit 2017
In Jin Cho, a Ph.D. student in the Department of Chemical and Biomolecular Engineering at KAIST received the best poster prize at the International Metabolic Engineering Summit 2017 held on October 24 in Beijing, China.
The International Metabolic Engineering Summit is a global conference where scientists and corporate researchers in the field of metabolic engineering present their latest research outcomes and build networks.
At this year’s summit, about 500 researchers from around the world participated in active academic exchanges, including giving keynote speeches and presenting posters.
During the poster session, the summit selects one person for the KeAi-synthetic and Systems Biotechnology Poster Award, two for Microbial Cell Factories Poster Awards, and three for Biotechnology Journal Poster Awards among the posters presented by graduate students, post-doctoral fellows and researchers. Cho received the KeAi-synthetic and Systems Biotechnology Poster Award. Her winning poster is on the biotransformation of p-xylene to terephthalic acid using engineered Escherichia coli.
Terephthalic acid is generally produced by p-xylene oxidation; however, this process requires a high temperature and pressure as well as a toxic catalyst during the reaction process.
Cho and Ziwei Luo, a Ph.D. student at KAIST, co-conducted the research and developed a successful biological conversion process. Compared to the existing chemical process, it does not require a high temperature and pressure; and it is environmentally friendly with a relatively high conversion rate of approximately 97%.
Cho’s advisor, Distinguished Professor Sang Yup Lee said, “Further research on glucose-derived terephthalic acid will enable us to produce biomass-based eco-friendly terephthalic acid through engineered Escherichia coli.”
2017.10.31 View 10473 -
Professor Dai Gil Lee Recognized by the ICCS
Emeritus Professor Dai Gil Lee, from the School of Mechanical and Aerospace Engineering at KAIST, received a special achievement award from the 20th International Conference on Composite Structures (ICCS).
ICCS is a renowned conference in the field of applied composite structures, which highlights the practicality of composite structures. This year, the conference was held at the Conservatoire National des Arts et Métiers (CNAM), Paris, France from September 4 to 7. Approximately 650 papers were presented from 45 countries.
Especially, the conference honored Emeritus Professor Lee, who has been engaged in ICCS since 1993 and received best paper award twice. The ICCS recognized him for serving with distinction in science and technology in the fields of composite materials and structures. As a member of the Editorial Board for many years, he gave significant support to the journal Composite Structures. At the conference, he gave a special lecture titled ‘Lightweight Carbon Composite Proton Exchange Membrane Fuel Cells’.
Professor Lee said, “I will dedicate myself to innovate Vanadium Redox Flow Battery-ESS (VRFB) based on the research findings announced at the conference and related patents. I am hoping that these efforts will contribute to solving energy issues around the world.”
2017.10.19 View 8487 -
International Students Start a New Semester at KAIST
(International students during a campus tour)
The 2017 fall semester began on August 28 and new and returning students are filling the campus. Our international students are one of the reasons the campus is becoming more dynamic and energetic.
It was easy to see groups of smiling international students walking around the campus. Every semester, KAIST welcomes hundreds of students from around the world to give them the opportunity to study at a world-leading university in science and technology.
This semester, approximately 150 students in degree-seeking programs and 220 exchange students from a total of 74 countries, including Germany, the United States, and France entered KAIST.
(Frederik Hansen, a student from DTU)
Frederik Hansen is an exchange student who came to KAIST this semester from Copenhagen, Denmark. He completed the undergraduate program at the Technical University of Denmark (DTU) and is now pursuing a master’s degree.
He decided to join KAIST because he felt the university is up-to-date with subjects in his field of interest.
Frederik, who majored in mechanical engineering, looks forward taking classes related to robotics and solid mechanics. Noting that it’s his first time visiting Asia, he hopes to experience and learn about Korean culture.
In an effort to help foreign students’ soft landing in KAIST, the International Office held a series of orientation programs over three days. The buddy program provides international freshmen with an opportunity to make Korean friends for a more successful life at KAIST, while giving domestic students a chance to learn about different cultures and perhaps build on the global capacity required for becoming a global leader. Information sessions also provided educational information that can support international students living in KAIST. Finally, the counseling program gives information about the KAIST counseling center and ISSS (International Scholar and Student Service). It provides a psychometric test service to those who wish to take it.
If you are interested in pursuing academic programs at KAIST, please visit the International Office via http://io.kaist.ac.kr/index.do .
2017.08.30 View 6860