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Native-like Spider Silk Produced in Metabolically Engineered Bacterium
Microscopic picture of 285 kilodalton recombinant spider silk fiber Researchers have long envied spiders’ ability to manufacture silk that is light-weighted while as strong and tough as steel or Kevlar. Indeed, finer than human hair, five times stronger by weight than steel, and three times tougher than the top quality man-made fiber Kevlar, spider dragline silk is an ideal material for numerous applications. Suggested industrial applications have ranged from parachute cords and protective clothing to composite materials in aircrafts. Also, many biomedical applications are envisioned due to its biocompatibility and biodegradability. Unfortunately, natural dragline silk cannot be conveniently obtained by farming spiders because they are highly territorial and aggressive. To develop a more sustainable process, can scientists mass-produce artificial silk while maintaining the amazing properties of native silk? That is something Sang Yup Lee at the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, the Republic of Korea, and his collaborators, Professor Young Hwan Park at Seoul National University and Professor David Kaplan at Tufts University, wanted to figure out. Their method is very similar to what spiders essentially do: first, expression of recombinant silk proteins; second, making the soluble silk proteins into water-insoluble fibers through spinning. For the successful expression of high molecular weight spider silk protein, Professor Lee and his colleagues pieced together the silk gene from chemically synthesized oligonucleotides, and then inserted it into the expression host (in this case, an industrially safe bacterium Escherichia coli which is normally found in our gut). Initially, the bacterium refused to the challenging task of producing high molecular weight spider silk protein due to the unique characteristics of the protein, such as extremely large size, repetitive nature of the protein structure, and biased abundance of a particular amino acid glycine. “To make E. coli synthesize this ultra high molecular weight (as big as 285 kilodalton) spider silk protein having highly repetitive amino acid sequence, we helped E. coli overcome the difficulties by systems metabolic engineering,” says Sang Yup Lee, Distinguished Professor of KAIST, who led this project. His team boosted the pool of glycyl-tRNA, the major building block of spider silk protein synthesis. “We could obtain appreciable expression of the 285 kilodalton spider silk protein, which is the largest recombinant silk protein ever produced in E. coli. That was really incredible.” says Dr. Xia. But this was only step one. The KAIST team performed high-cell-density cultures for mass production of the recombinant spider silk protein. Then, the team developed a simple, easy to scale-up purification process for the recombinant spider silk protein. The purified spider silk protein could be spun into beautiful silk fiber. To study the mechanical properties of the artificial spider silk, the researchers determined tenacity, elongation, and Young’s modulus, the three critical mechanical parameters that represent a fiber’s strength, extensibility, and stiffness. Importantly, the artificial fiber displayed the tenacity, elongation, and Young’s modulus of 508 MPa, 15%, and 21 GPa, respectively, which are comparable to those of the native spider silk. “We have offered an overall platform for mass production of native-like spider dragline silk. This platform would enable us to have broader industrial and biomedical applications for spider silk. Moreover, many other silk-like biomaterials such as elastin, collagen, byssus, resilin, and other repetitive proteins have similar features to spider silk protein. Thus, our platform should also be useful for their efficient bio-based production and applications,” concludes Professor Lee. This work is published on July 26 in the Proceedings of the National Academy of Sciences (PNAS) online.
2010.07.28
View 19878
President Suh Hosted Press Conference with Seoul-based Correspondents, on March 9, 2010
President Suh Hosted Press Conference with Seoul-based Correspondents, on March 9, 2010 President Nam-Pyo Shu had a press conference with foreign correspondents based in Seoul, South Korea, on March 9, 2010 at Seoul Foreign Correspondents’ Club (SFCC). Prior to the conference, the president and correspondents attended a ceremony for the completion of Online Electric Vehicles (OLEV) that carries passengers to look around the amusement park, Seoul Grand Park, in Gewacheon City. OLEV was developed and built by KAIST. Following President Suh’s opening speech, a questions and answers (Q&A) session between the president and reporters proceeded. In his opening speech, President Suh said electric vehicles are an alternative to conventional automobiles with combustion engines, and in order to manufacture affordably priced electric vehicles on a large scale, their charging should be streamlined. In response, KAIST has come up with the online electric vehicle concept. He added, without installing separate charging stations, OLEV receives electric power from the cables buried underground while driving, idling, or parking. Its connection to a power source is non-contact. President Suh expressed his excitement for demonstrating OLEV at Seoul Grand Park that its system works as KAIST has designed and predicted. He showed his confidence that KAIST is indeed at the stage to implement OLEV in Seoul City soon and hoped to demonstrate it at the upcoming G-20 Summit to be held in November 2010 in Seoul City. During the Q&A session, reporters cited the construction of OLEV at the amusement park and mainly asked about a possibility of its commercialization. Other topics, they also questioned about, were hurdles related to the development and commercialization of OLEV; level of cooperation received from industries and central/local governments; technological breakthroughs and accomplishments; future development plans for the commercialization; and reactions from the public and government. Media outlets participated in the conference were Reuters, AFP, the International Herald Tribune, ABC News, Bloomberg News, Businessweek, Voice of America, Sankei Shimbun, and etc.
2010.03.16
View 11510
KAIST introduced environmentally friendly public transportation to Seoul Grand Park.
KAIST introduced environmentally friendly public transportation to Seoul Grand Park. First step toward the commercialization of Online Electric Vehicle (OLEV) An online electric vehicle (OLEV) developed by KAIST replaced a trackless combustion-engine train running inside Seoul Grand Park in Gwacheon City, South Korea. On March 9, 2010, Seoul City and KAIST celebrated the completion of OLEV that picks up electricity from power cables buried underground through a non-contact magnetic charging method, called electromagnetic induction. Electromagnetic induction is the process of inducing electric current in a coil with the help of a magnet. The pickup unit installed underneath OLEV collects electricity from a roadway and distributes the power either to operate the vehicle or for battery storage. Whether running or stopped, OLEV constantly receives electric power through the underground cables. As a result, OLEV mitigates the burden of equipping electric automobiles with heavy, bulky batteries—OLEV’s battery size is one-fifth that of the batteries installed in electric vehicles currently on the market. There is no need to establish massive charging stations or to set aside much time for recharging. If the underground power lines installed on road curbs, bus stops, parking lots, and intersections, the power system could support a substantial portion of public transportation: For example, KAIST estimates that by establishing 20% of the road infrastructure for a bus route in Seoul City, the city could offer its citizens the online electric buses. The non-contact charging of vehicles while running, idling, or parking is an important and practical technology necessary for the development of commercialized electric vehicles. This technology solves many of the issues related to the current batteries of electric vehicles, including size, expense, and repair/maintenance. In addition, non-contact charging is safer because it prevents potential electrical hazards, such as electric shock, that result from direct contact with power sources. Furthermore, it is more convenient to drive vehicles without overhead wires directly connected to power lines, as is necessary for streetcars and trams. The recharging strips are divided into several meters of segments in length, and vehicles receive the power each time they pass over one. In other words, a sensor is affixed within each segment. When a car with the pickup equipment drives over the segment, the sensor is turned on for the car to receive electricity. This means that when a car without the pickup equipment passes over the segment, it will not collect any electricity. The power supply via on/off switch (sensors) relieves safety concerns about electromagnetic field (EMF). Pedestrians or cars without the pickup unit will not be exposed to EMF because the sensor embedded in the segments will not work, thus no electricity generated. In addition, even under the circumstance of EMF yield, the test results for OLEV are well below the 1998 the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guideline, 62.5mG at 20khz. OLEV’s EMF test results range from 20mG (inside OLEV while running) to 50mG (around OLEV while parking). When talking about a wireless energy transfer such as electromagnetic induction, the most critical issue is how to reserve an air gap of 12cm (in accordance with Korean law) between the surface of roads and the bottom of vehicles while having 60% power transmission efficiency or above. There was a similar research done in the US at University of Berkley—their research was considered unsuccessful because they obtained an air gap of 5-7cm with 60% maximum level of efficiency. Besides, their electromagnetic field (EMF) was quite high (2000A), and they were unable to bring down the high cost of installing power supply system. By contrast, for the first time in the world, KAIST has succeeded to obtain 12cm (and up to 17cm) of air gap with more than 70% efficiency level of power transmission. The EMF is also well below the international standard of 62.5mG. In a nutshell, KAIST has achieved a core technology in terms of capacity, efficiency, and EMF to develop electric vehicles for commercial use. The city government of Seoul and KAIST signed a Memorandum of Understating (MOU) on the development of an online electric vehicle in August 2009. Against the backdrop of the public’s increased awareness of environmental pollution and the depletion of fossil fuels, the two organizations agreed to introduce eco-friendly vehicles to the city’s public transportation, beginning with the introduction of a trial version of OLEV to places like an amusement park, bus terminal, airport, shopping mall, and the like. KAIST’s OLEV research team is made up of experts from a variety of fields, including electrical and electronics engineering, computer sciences, civil engineering, information technology, and mechanical engineering. OLEV’s success at Seoul Grand Park is a result of KAIST’s innovative initiatives on convergence research, and KAIST has submitted more than 120 applications for patents right in connection with the development of OLEV. Online Electric Vehicle at Seoul Grand Park In terms of power transmission efficiency, KAIST’s research team achieved a maximum pick-up capacity of 62kw/h, 74% with an air gap height of 13cm from a road to the bottom of a vehicle. Composed of one engine and three passenger cars, OLEV travels along a total length of 2.2km beltway. There are four sections of power supply infrastructure established on the route (Sections 1, 2, and 3: 122.5 meters long each, and Section 4: 5 meters long). The power supply cables were laid underground for a total of 372.5 meters, 16% of the total distance of the 2,200 meter route.
2010.03.12
View 14442
KAIST to Host ITTP Conference in Tunisia
KAIST"s Global IT Technology Program (ITTP) will host an international conference at Hammamet Hotel in Tunisia in cooperation with its counterpart at Seoul National University (SNU) on Nov. 23, university authorities said on Wednesday (Nov. 18). The event is a pre-conference for the ICT4All Forum on Nov. 24-25 which the Tunisian government is organizing with the ADB, World Bank, Arab Society for Intellectual Property and the UTICA to deal with developing information and communication technologies. KAIST"s ITTP which started in 2006 is designed to build global network of IT leaders around the world. The program supported by the Korean Ministry of Knowledge and Economy offers a customized master"s and doctoral degree program for foreign government officials, employees of public institutions and senior researchers at national research centers working in the IT fields. Scholarships are provided for all trainees, for up to 2 years for master"s students and up to 3 years for doctoral students. The program focuses on transferring advanced technologies and business strategies of Korea to the global IT leaders of the next generation. During the conference, seven government officials from as many countries currently under the KAIST or SNU programs will present international cooperation cases based on their own experiences in the IT fields. KAIST ITTP organizers will also provide an educational session on the mobile government for Tunisian experts and conference participants in the information and communications fields.
2009.11.20
View 15279
Int'l Telematic Music Concert for Peace to Take Place on Nov. 20
Renowned musicians in five international locations perform new contemporary music works for peace through a real-time performance on the internet. Local audiences in Seoul, Banff, New York, San Diego and Belfast will also have a chance to hear a program. In Seoul, the "International Telematic Music Concert for Peace" will be held at the LeeHaeRang Art Theater, Dongguk University, in Seoul on Nov. 20 at 9:30 a.m., under the presentation of KAIST"s Graduate School of Culture Technology and MARTE Lab, Dongguk University. Telematic music is real-time performance via the internet by musicians in different geographic locations. The program of the concert includes "Hope"s Dream" by Mark Dresser and Sarah Weaver; "Disparate Bodies" by Pedro Rebelo, "Rock, Paper, Scissors" by Chris Chafe. The Korean act to be performed is "Green-colored Harmony" by Jun Kim. In addition to the two Korean universities, the World Association of Former United Nations Internes and Fellows (WAFUNIF), University of California San Diego, the Banff Center of Canada and Queen"s University in Belfast are participating in the project. The performance will take place on high-bandwidth internet with JackTrip audio software developed by Chris Chafe and Access Grid video software developed at Argonne National Laboratory. "Connecting the five different cities together through super-speed Internet network and transmitting sound and images in real time is challenging technically. But, we also expect that more exciting results will be created in the course of transforming the sound into visual images," said Woon-Seung Yeo, a professor of the Graduate School of Culture Technology, who was responsible for visuals in the project.
2009.11.19
View 15302
Transparent Antenna for Automobile Developed
A research team led by Prof. Jae-Woo Park of the School of Electrical Engineering & Computer Science, KAIST, developed a transparent antenna for the next-generation automobiles, university authorities said on Monday (Aug. 17). The development was made possible through joint researches with the Hyundai-Kia Automotive Group; Winncom, a car antenna manufacturer; and a group of researchers led by Han-Ki Kim of the Department of Display Materials Engineering at Kyung Hee University in Seoul. The transparent antennas were developed in two kinds -- one for the HSDPA (High-Speed Downlink Packet Access), a new protocol for mobile telephone data transmission, and the other for transmitting and receiving radio wave for emergency call. Using the transparent electrically conductive film formation technology, the transparent antennas are to be mounted on the windshield of a vehicle. "The development of transparent antenna represents a step forward for the advancement of the next-generation automotive electronic technology," said Seong-woo Kim, a senior researcher at the Hyundai-Kia Group.
2009.08.18
View 15317
Prof. Chung Appointed Chief Design Officer of Seoul City
Prof. Kyung-Won Chung of the Department of Industrial Design, KAIST, has been appointed as the new chief design officer of the Seoul Metropolitan City, university sources said on Tuesday (May 26). Chung succeeded Prof, Young-Gull Kwon of Seoul National University who served as the inaugural head of the design division since 2007. The deputy-mayor level position has a two-year term. With a vision to turn Seoul into a "global design hub," the Seoul city administration established the design division and initiated a slew of initiatives including design competitions aimed at improving the city"s looks. Prof. Chung graduated from Seoul National University and its graduate school. Then, he earned a master"s degree from Syracuse University, New York, and a doctorate from Manchester Metropolitan University in Britain. Since February 2009, he has served as an executive of the newly-created Seoul Design Foundation. He also served as president of the Korea Institute of Design Promotion (KIDP) from February 2000 through May 2003.
2009.05.28
View 10676
Former Information and Communication Minister Soonhoon Bae appointed to Vice president of KAIST
“KAIST graduate school of management will be a world-class graduate school of management” Professor Soonhoon Bae was appointed to the vice president of KAIST in Seoul campus on August 16. Vice president Bae started his carrier with Daewoo Inc. as the head of the technical H.Q. in Daewoo Heavy Industry in 1976, and took office as the CEO of Daewoo Electronics (1991-95) and Daewoo Inc. (1995-97). He was also the Minister of Information and Communication in 1998 and the chairman of the Presidential Committee on Northeast Asian Business Hub during 2004-05. He became an issue by ‘TANKism’, a motto of making strong and core function-convergent electronic goods, when he was the CEO of Daewoo Electronics in 1992. From 1999, he’s made lectures for KAIST graduate school of techno management and Classroom No. 101 in Supex Management Hall where he has made lectures is called ‘tank classroom’. Vice president Bae expressed his intention of the globalization and level-up of the school by saying, “I will focus on basic researches of management and thus raise the level of KAIST graduate school up to be qualified for Nobel Prize. I’ve taken many high-rank positions such as the CEO of major companies and the minister, however, position doesn’t matter at all. I am fully satisfied with the fact that the organizations that I belonged to have been reborn as world-class communities, and I am planning to lead KAIST graduate school of management in such a direction.”
2006.09.05
View 15834
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