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Structural Insight into the Molecular Mechanism of PET Degradation
A KAIST metabolic engineering research team has newly suggested a molecular mechanism showing superior degradability of poly ethylene terephthalate (PET).
This is the first report to simultaneously determine the 3D crystal structure of Ideonella sakaiensis PETase and develop the new variant with enhanced PET degradation.
Recently, diverse research projects are working to address the non-degradability of materials. A poly ethylene terephthalate (PET)-degrading bacterium called Ideonella sakaiensis was recently identified for the possible degradation and recycling of PET by Japanese team in Science journal (Yoshida et al., 2016). However, the detailed molecular mechanism of PET degradation has not been yet identified.
The team under Distinguished Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering and the team under Professor Kyung-Jin Kim of the Department of Biotechnology at Kyungpook National University conducted this research. The findings were published in Nature Communications on January 26.
This research predicts a special molecular mechanism based on the docking simulation between PETase and a PET alternative mimic substrate. Furthermore, they succeeded in constructing the variant for IsPETase with enhanced PET-degrading activity using structural-based protein engineering.
It is expected that the new approaches taken in this research can be background for further study of other enzymes capable of degrading not only PET but other plastics as well.
PET is very important source in our daily lives. However, PET after use causes tremendous contamination issues to our environment due to its non-biodegradability, which has been a major advantage of PET. Conventionally, PET is disposed of in landfills, using incineration, and sometimes recycling using chemical methods, which induces additional environmental pollution. Therefore, a new development for highly-efficient PET degrading enzymes is essential to degrade PET using bio-based eco-friendly methods.
Recently, a new bacterial species, Ideonella sakaiensis, which can use PET as a carbon source, was isolated. The PETase of I. sakaiensis (IsPETase) can degrade PET with relatively higher success than other PET-degrading enzymes. However, the detailed enzyme mechanism has not been elucidated, hindering further studies.
The research teams investigated how the substrate binds to the enzyme and which differences in enzyme structure result in significantly higher PET degrading activity compared with other cutinases and esterases, which make IsPETase highly attractive for industrial applications toward PET waste recycling.
Based on the 3D structure and related biochemical studies, they successfully predicted the reasons for extraordinary PET degrading activity of IsPETase and suggested other enzymes that can degrade PET with a newly-classified phylogenetic tree. The team proposed that 4 MHET moieties are the most properly matched substrates due to a cleft on structure even with the 10-20-mers for PET. This is meaningful in that it is the first docking simulation between PETase and PET, not its monomer.
Furthermore, they succeeded in developing a new variant with much higher PET-degrading activity using a crystal structure of this variant to show that the changed structure is better to accommodate PET substrates than wild type PETase, which will lead to developing further superior enzymes and constructing platforms for microbial plastic recycling.
Professor Lee said, “Environmental pollution from plastics remains one of the greatest challenges worldwide with the increasing consumption of plastics. We successfully constructed a new superior PET-degrading variant with the determination of a crystal structure of PETase and its degrading molecular mechanism. This novel technology will help further studies to engineer more superior enzymes with high efficiency in degrading. This will be the subject of our team’s ongoing research projects to address the global environmental pollution problem for next generation.”
This work was supported by the Technology Development Program to Solve Climate Changes on Systems Metabolic Engineering for Biorefineries (NRF-2012M1A2A2026556 and NRF-2012M1A2A2026557) from the Ministry of Science and ICT through the National Research Foundation of Korea. Further Contact: Dr. Sang Yup Lee, Distinguished Professor, KAIST, Daejeon, Korea (leesy@kaist.ac.kr, +82-42-350-3930)
(Figure: Structural insight into the molecular mechanism of poly(ethylene terephthalate) degradation and the phylogenetic tree of possible PET degrading enzymes. This schematic diagram shows the overall conceptualization for structural insight into the molecular mechanism of poly (ethylene terephthalate) degradation and the phylogenetic tree of possible PET degrading enzymes.)
2018.01.31 View 9795 -
One-Step Production of Aromatic Polyesters by E. coli Strains
KAIST systems metabolic engineers defined a novel strategy for microbial aromatic polyesters production fused with synthetic biology from renewable biomass. The team of Distinguished Professor Sang Yup Lee of the Department of Chemical and Biomolecular Engineering produced aromatic polyesters from Escherichia coli (E. coli) strains by applying microbial fermentation, employing direct microbial fermentation from renewable feedstock carbohydrates.
This is the first report to determine a platform strain of engineered E. coli capable of producing environmentally friendly aromatic polyesters. This engineered E. coli strain, if desired, has the potential to be used as a platform strain capable of producing various high-valued aromatic polyesters from renewable biomass. This research was published in Nature Communications on January 8.
Conventionally, aromatic polyesters boast solid strength and heat stability so that there has been a great deal of interest in fermentative production of aromatic polyesters from renewable non-food biomass, but without success.
However, aromatic polyesters are only made by feeding the cells with corresponding aromatic monomers as substrates, and have not been produced by direct fermentation from renewable feedstock carbohydrates such as glucose.
To address this issue, the team prescribed the detailed procedure for aromatic polyester production through identifying CoA-transferase that activates phenylalkanoates into their corresponding CoA derivatives. In this process, researchers employed metabolic engineering of E. coli to produce phenylalkanoates from glucose based on genome-scale metabolic flux analysis. In particular, the KAIST team made a modulation of gene expression to produce various aromatic polyesters having different monomer fractions.
The research team successfully produced aromatic polyesters, a non-natural polymer using the strategy that combines systems metabolic engineering and synthetic biology. They succeeded in biosynthesis of various kinds of aromatic polyesters through the system, thus proving the technical excellence of the environmentally friendly biosynthetic system of this research. Furthermore, his team also proved the potential of expanding the range of aromatic polyesters from renewable resources, which is expected to play an important role in the bio-plastic industry.
Professor Lee said, “An eco-friendly and sustainable chemical industry is the key global agenda every nation faces. We are making a research focus to a biochemical industry free from petroleum dependence, and conducting diverse research activities to address the issue. This novel technology we are presenting will serve as an opportunity to advance the biochemical industry moving forward.”
This work was supported by the Intelligent Synthetic Biology Center through the Global Frontier Project (2011-0031963) and also by the Technology Development Program to Solve Climate Changes on Systems Metabolic Engineering for Biorefineries (NRF-2012M1A2A2026556 and NRF-2012M1A2A2026557) from the Ministry of Science and ICT through the National Research Foundation of Korea.
Figure: Biosynthesis of aromatic polyesters by metabolically engineered E. coli.This schematic diagram shows the overall conceptualization of how metabolically engineered E. coli produced aromatic polyesters from glucose.
2018.01.09 View 7890 -
President Shin Reaffirms Innovation Initiatives in New Year Speech
(President Shin and representatives of faculty, students, staff celebrate the New Year in a reception held on January 2 at the auditorium.)
The KAIST community gathered to celebrate a fresh start for the year 2018. At the ceremony, held in the auditorium on January 2, members of KAIST community reaffirmed their commitment to be the trailblazers of Korea and beyond through unwavering innovations.
President Sung-Chul Shin presented his new vision and plan in his New Year speech, which focused on innovation for enhancing institutional competitiveness and global visibility. He said that as you are the future of KAIST, KAIST is the future of Korea. KAIST’s vision for a better future will have a significant impact on national progress and beyond. He stressed that innovation in the five pillars of education, research, technology commercialization, globalization, and future strategy will further advance the excellence of KAIST.
At the ceremony, President Shin also presented the award for ‘the KAISTian of the Year’ to Professor YongKeun Park of the Department of Physics. The annual award recognizes a distinguished professor whose academic accomplishments made the most significant impact.
In his New Year speech, President Shin said that the year 2018 will provide an opportunity to take a leap forward for becoming a ‘Global Value Creative, World-Leading University. The Vision 2031 Committee endorsed the five innovation initiatives to fulfill KAIST’s long-term vision and will open its recommendations to the public on March 20.
Educational innovation tops the initiatives. President Shin explained that the future of Korea is in the hands of talented individuals in science and technology, emphasizing the need to nurture creative, transdisciplinary talents with the capacity to enhance the social value of science and technology.
To this end, KAIST will establish a new undergraduate non-departmental program for transdisciplinary education. This plan will eventually provide students with more options in choosing their major, as well as help students build a strong foundation in basic science and engineering and encourage multidisciplinary approaches.
For creating an innovative institutional research infrastructure, KAIST plans to build a Network of Excellence for the Fourth Industrial Revolution (NExFire) for convergence research. The plan of ‘Cross-Generational Collaborative Labs,’ will bring out a new collaboration platform by pairing up senior and junior faculty. President Shin said it will be a stepping stone to extend the spectrum of knowledge without any cessation.
For technology commercialization, KAIST will maximize its intellectual property and economic value by stimulating technology-invested companies and startups. Close cooperation with venture capitalists at home and abroad will further accelerate the commercialization drive at KAIST.
Saying that the globalization is no long an option but a necessity, he stressed KAIST will strengthen its efforts to established a bilingual campus. “KAIST will make every effort to create a more welcoming and comfortable atmosphere for the international community and their families. We will expand benefits to our international community, such as access to the KAIST Child Care Center and collaboration with the Taejon Christian International School (TCIS),” he said. President Shin added he will further expand global networks and partnerships this year, participating in a diverse range of international events at home and abroad for increasing global visibility.
He also said that well-designed future strategies will complete innovation initiatives. The Future Strategy Research Center will serve as a think tank for identifying future agendas, establishing strategies and advocating for them.
In addition to the five innovation initiatives, President Shin emphasized a new organizational culture that embraces inclusiveness and mutual respect among all of the members of KAIST.
“So far, the ideal qualifications expected of KAISTians have included creativity and a challenging spirit. From now on, we will nurture talents with a focus on the 3Cs: Creativity, Challenge, and Caring. I would like to make a campus in which all members care for each other to help attain mutual growth with warmth and respect," he said.
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2018.01.02 View 10378 -
Strengthening Industry-Academia Cooperation with LG CNS
On November 20, KAIST signed an MoU with LG CNS for industry-academia partnership in education, research, and business in the fields of AI and Big Data. Rather than simply developing education programs or supporting industry-academia scholarships, both organizations agreed to carry out a joint research project on AI and Big Data that can be applied to practical business.
KAIST will collaborate with LG CNS in the fields of smart factories, customer analysis, and supply chain management analysis.
Not only will LG CNS offer internships to KAIST students, but it also will support professors and students who propose innovative startup ideas for AI and Big Data. Offering an industry-academia scholarship for graduate students is also being discussed. Together with LG CNS, KAIST will put its efforts into propose projects regarding AI and Big Data in the public sector.
Furthermore, KAIST and LG CNS will jointly explore and carry out industry-academia projects that could be practically used in business. Both will carry out the project vigorously through strong cooperation; for instance, LG CNS employees can be assigned to KAIST, if necessary. Also, LG CNS’s AI and Big Data platform, called DAP (Data Analytics & AI Platform) will be used as a data analysis tool during the project and the joint outcomes will be installed in DAP.
KAIST professors with expertise in AI deep learning have trained LG CNS employees since the Department of Industrial & Systems Engineering established ‘KAIST AI Academy’ in LG CNS last August.
“With KAIST, the best research-centered university in Korea, we will continue to lead in developing the field of AI and Big Data and provide innovative services that create value by connecting them to customer business,” Yong Shub Kim, the CEO of LG CNS, highlighted.
2017.11.22 View 12699 -
College of Business Honored with the WRDS-SSNR Innovation Award
(Professor Inmoo Lee (far left), Robert Zarazowski (WRDS), Gregg Gordon (SSRN) and Professor Jae Kyu Lee)
The KAIST College of Business received the WRDS (Wharton Research Data Services)-SSNR Innovation Award for the Asia-Pacific region on October 31 during the AACSB Asia-Pacific Conference in Seoul.
The WRDS-SSRN Innovation Award is intended to elevate the visibility of pioneering research across a broad range of financial and economic topics. Three winners are selected annually from across North America, Europe, and the Asia Pacific based on their ability to demonstrate innovation and research excellence.
The award was created through collaboration with SSRN, the world’s leading early-stage research platform and Elsevier, a global information analytics company specializing in science and health. It honors top business schools that produce exceptional data-driven research. A part of the Wharton School of the University of Pennsylvania, WRDS provides global corporations, universities, and regulatory agencies with the thought leadership, data access, and analytics needed to enable impactful research.
The Dean of the College of Business Youngbae Kim, said that KAIST has been taking the lead in responding to global trends, offering many innovative programs such as an MBA for Social Entrepreneurship and the Master Course for Green Growth Management. KAIST already has been selected as the Most Innovative University in the Asia-Pacific Region by Thomson Reuters for the last two years.
Robert Zarazowski, managing director of WRDS said they recognize and support the outstanding achievement taking place at KAIST as well as its commitment to growth and innovation in business education.
2017.11.03 View 7750 -
KAIST-WEF Roundtable on Inclusive Growth and Job Creation
The World Economic Forum (WEF) will join KAIST in an effort to address sweeping global problems in the wake of the Fourth Industrial Revolution. The two will co-host a roundtable on ‘Shaping Korea’s Priorities for Inclusive Growth and Job Creation in the Fourth Industrial Revolution’ on October 13 at Lotte Hotel in Seoul.
The roundtable will bring together leaders from government, industry, universities, and non-profit civic organizations to have an in-depth discussion on a thought-provoking agenda of inclusive growth and job creation which scientific and technological changes will bring about. The event will provide a platform to explore practical collaboration and innovative strategies for better job creation and innovation ecosystems.
The two will also sign an MOU for collaboration between the Fourth Industrial Revolution Information Center (FIRIC) of KAIST and the WEF Center for the Fourth Industrial Revolution (C4IR).
President Sung-Chul Shin of KAIST and the Head of the WEF Center for the Fourth Industrial Revolution, Murat Sonmez, will lead the panel discussion titled ‘Inclusive Growth and the Fourth Industrial Revolution’ which will be attended by leaders from government, industry, and non-profit civic organizations.
At the breakout sessions, the topics will be “Future Jobs” and the “Creation of Innovation Ecosystems”. Additionally, a discussion on the “SME 4.0 Initiative”, which is a program pushed forward by KAIST in collaboration with local governments, will talk about job creation through innovation in small and medium-sized enterprises (SMEs). The WEF will introduce their two-year activities and research on the Fourth Industrial Revolution, which have great potential and a high possibility of successfully undergoing the revolution, to Korea.
Since WEF Executive Chairman Klaus Schwab brought up the topic of the Fourth Industrial Revolution, the WEF has been leading agenda topics and discussions on high-profile matters, including ‘technology-driven but human-centered inclusive growth’ in predicting the future of jobs.
The WEF is a nonprofit organization committed to addressing the world’s weightiest problems. It is best known for its annual meetings in Davos, Switzerland, which attracts leaders from around the world. KAIST has been participating in this summit since 2009. President Shin will also attend the upcoming Davos summit next January. Distinguished Professor Sang Yup Lee who heads the KAIST Institute and the FIRIC is the co-chair of the Global Council on Biotechnology and a member of the Global Future Council on the Fourth Industrial Revolution at the WEF.
Moreover, President Shin and Mr. Sonmez will explain the background of the roundtable and share the results of the sessions at a joint news conference.
2017.09.28 View 10994 -
Sangeun Oh Recognized as a 2017 Google Fellow
Sangeun Oh, a Ph.D. candidate in the School of Computing was selected as a Google PhD Fellow in 2017. He is one of 47 awardees of the Google PhD Fellowship in the world.
The Google PhD Fellowship awards students showing outstanding performance in the field of computer science and related research. Since being established in 2009, the program has provided various benefits, including scholarships worth $10,000 USD and one-to-one research discussion with mentors from Google.
His research work on a mobile system that allows interactions among various kinds of smart devices was recognized in the field of mobile computing. He developed a mobile platform that allows smart devices to share diverse functions, including logins, payments, and sensors. This technology provides numerous user experiences that existing mobile platforms could not offer. Through cross-device functionality sharing, users can utilize multiple smart devices in a more convenient manner. The research was presented at The Annual International Conference on Mobile Systems, Applications, and Services (MobiSys) of the Association for Computing Machinery in July, 2017.
Oh said, “I would like to express my gratitude to my advisor, the professors in the School of Computing, and my lab colleagues. I will devote myself to carrying out more research in order to contribute to society.”
His advisor, Insik Shin, a professor in the School of Computing said, “Being recognized as a Google PhD Fellow is an honor to both the student as well as KAIST. I strongly anticipate and believe that Oh will make the next step by carrying out good quality research.”
2017.09.27 View 13457 -
Photoacoustic Imaging and Photothermal Cancer Therapy Using BR Nanoparticles
(Professor Sangyong Jon and PhD Candidate Dong Yun Lee)
Sangyong Jon, a professor in the Department of Biological Sciences at KAIST, and his team developed combined photoacoustic imaging and photothermal therapy for cancer by using Bilirubin (BR) nanoparticles.
The research team applied the properties of a bile pigment called BR, which exerts potent antioxidant and anti-inflammatory effects, to this research.
The team expects this research, which shows high biocompatibility as well as outstanding photoacoustic imaging and photothermal therapy, to be an appropriate system in the field of treatment for cancer.
In the past, the research team developed a PEGylated bilirubin-based nanoparticle system by combining water-insoluble BR with water-soluble Polyethylene Glycol (PEG).
This technology facilitated BR exerting antioxidants yet prevented them from being accumulated in the body. Its efficiency and safety was identified in an animal disease model, for conditions such as inflammatory bowel disease, islet cell transportation, and asthma.
Differing from previous research methods, this research applied the different physicochemical properties of BR to cancer treatment.
When the causative agent of jaundice, yellow BR, is exposed to a certain wavelength of blue light, the agent becomes a photonic nanomaterial as it responses to the light. This light-responsive nanomaterial can be used to cure jaundice because it allows for active excretion in infants.
Secondly, the team identified that BR is a major component of black pigment gallstones which can be often found in gall bladders or bile ducts under certain pathological conditions. The findings show that BR forms black pigment gallstones without the role of an intermediate or cation, such as calcium and copper. The research team combined cisplatin, a platinum metal-based anticancer drug, with BR so that BR nanoparticles changed the solution color from yellow to purple.
The team also examined the possibility of cisplatin-chelated BR nanoparticles as a probe for photoacoustic images. They found that considerable photoacoustic activity was shown when it was exposed to near infrared light. In fact, the photoacoustic signal was increased significantly in tumors of animals with colorectal cancer when the nanoparticles were administered to it intravenously. The team expects a more accurate diagnosis of tumors through this technology.
Moreover, the team assessed the photothermal effects of cisplatin-chelated BR nanoparticles. The research showed that the temperature of tumors increased by 25 degrees Celsius within five minutes when they were exposed to near infrared light, due to the photothermal effect. After two weeks, their size was reduced compared to that of other groups, and sometimes the tumors were even necrotized.
Professor Jon said, “Existing substances have a low biocompatibility and limitation for clinical therapy because they are artificially oriented; therefore, they might have toxicity. I am hoping that these cisplatin-chelated BR-based nanoparticles will provide a new platform for preclinical, translational research and clinical adaptation of the photoacoustic imaging and photothermal therapy.”
The paper (Dong Yun Lee as a first author) was published online in the renowned journal in the field of applied chemistry, Angewandte Chemi International Edition, on September 4. This research was sponsored by the National Research Foundation of Korea.
(Schematic diagram of the research)
(From left: Bilirubin nanoparticles, cisplatin-chelated Bilirubin nanoparticles)
2017.09.26 View 9490 -
Humicotta Wins the Silver Prize at the 2017 IDEA
The 3D-printed ceramic humidifier made by the research team led by Professor Sang-Min Bae won the silver prize at the 2017 International Design Excellence Awards (IDEA). Professor Bae’s ID+IM team was also listed as winners of three more appropriate technology designs at the IDEA. The awards, sponsored by the Industrial Designers Society of America, are one of the three prestigious design awards including the Red Dot Design Award and the iF Design Award in Germany.
The silver prize winner in the category of home and bath, Humicotta is an energy-efficient, bacteria free, and easy to clean humidifier. It includes a base module and filter. The base is a cylindrical pedestal with a built-in fan on which the filter is placed. The filter is a 3D-printed honeycomb structure made of diatomite. When water is added, the honeycomb structure and porous terracotta maximize natural humidification. It also offers an open platform service that customizes the filters or provides files that users can use their own 3D printer.
Professor Bae’s team has worked on philanthropy design using appropriate technology as their main topic for years. Their designs have been recognized at prestigious global design awards events, winning more than 50 prizes with innovative designs made for addressing various global and social problems.
The Light Funnel is a novel type of lighting device designed for off-grid areas of Africa. It helps to maximize the natural light effect in the daytime without any drastic home renovations. It consists of a transparent acrylic sphere and a reflective pathway. After filling the acrylic sphere with water and placing it on a rooftop, sunlight passes into the house through the water inside the sphere. It provides a lighted environment nine times brighter than without it. Also, once installed, it can be used almost permanently.
The Maasai Smart Cane is made using wood sticks purchased through fair trade with the Maasai tribe. GPS is installed into the grip of the birch-tree cane, so that cane users can send a signal when in an emergency situation. All of the proceeds of this product go to the tribe.
S.Cone is a first aid kit made in collaboration with Samsung Fire and Marine Insurance. The traffic cone-shaped kit is designed to help users handle an emergency situation intact and safe. The S.Cone has unique versions for fires, car accidents, and marine accidents. For example, the S.Cone for fires is equipped with a small fire extinguisher, smoke mask, and fire blanket. The cap of the S.Cone also functions as an IoT station connecting the fire and gas detector with smart phones.
Professor Bae said of his team’s winning design products, “By making the data public, any person can design their own humidifier if they have access to a 3D-printer. We want it to be a very accessible product for the public. The Light Funnel and Maasai Smart Cane are designed for economically-marginalized populations and the elderly. We will continue to make the best designed products serving the marginalized 90% of the population around the world.”
2017.09.14 View 28003 -
2017 KAIST Tech Fair to Showcase Ten Cutting-Edge Technologies
KAIST will showcase the ten most cutting-edge technologies developed by KAIST faculty and researchers at the 2017 KAIST Tech Fair. The fair will be held on September 12 at the COEX in Seoul. The fair will bring companies, venture capitalists, and tech consultants from around the country to learn about the most commercially potential technology from KAIST.
The ten technologies, all already patented, will be highly relevant for the new industrial trends summed up by the Fourth Industrial Revolution. They include the fields of ICT, unmanned transportation, AI, robotics, IoT, nano, and big data.
The Technology Evaluation Committee, comprised of the heads of the departments at KAIST, patent lawyers, and venture capitalists, selected the ten technologies based on their applicability, innovativeness, and marketability. The selectees will be provided with various commercialization support and services including the manufacturing of prototypes, marketing consultation at home and abroad, as well as handling IPR issues, among others.
KAIST will hold an information session as well as consultations for successful technology commercialization as one of the innovative plans proposed by the KAIST President Sung-Chul Shin. This session will invite 200 entrepreneurs who are interested in the selected technologies.
Associate Vice President of University-Industry Cooperation Kyung Cheol Choi said, “Starting with the selection of 2017 top ten crucial technologies, KAIST will continue supporting technology marketing as well as its successful transfer. KAIST will make effort to carry out university-industry cooperation and find core patent technologies and project ideas in order to stimulate technology commercialization.”
The list of the ten critical patent technologies selected by KAIST is as follows:
▶ Catalyst-Decorated Nanofiber Sensor for Health Monitoring
By Professor Il-Doo Kim (Department of Materials Science and Engineering)
Human breath carries diverse components of diseases such as asthma, lung cancer, type 1 diabetes mellitus, and halitosis. Thus, it is possible to analyze exhaled breath very rapidly with a simple analyzing process and it can detect trace changes in exhaled breath components, which trigger diseases.
The research team developed highly sensitive and selective chemical gas sensors that can detect specific disease, using protein-encapsulated nanocatalysts. They can diagnose certain diseases by analyzing human exhaled breath. This technology enables the early monitoring of various diseases through pattern recognition of biomarker gases associated with the diseases in human exhalation.
The established sensing libraries can detect biomarker species with high sensitivity and selectivity. The team hopes that the new and innovative breath gas analysis platform will be very helpful for reducing medical expenditures and the continuous monitoring of physical conditions.
# Detection of environmental toxic gases, monitoring of body health condition
Figure (a) Mobile device integrated with nanofiber based MEMS sensorsFigure (b) Exhaled breath pattern recognition: principle component analysis for the accurate detection of acetone, hydrogen sulfide, and toluene gases
▶ Technology for a Cancer Cure Using Big Data and Simulating Biological Network By Professor Kwang-Hyun Cho (Department of Bio and Brain Engineering)
The complex and heterogeneous nature of cancer, which results in highly variable drug responses, is a major obstacle in curing cancer. Previous methods to predict drug responses mostly focus on the static analysis of genome-wide alternations, resulting in a limitation for the understanding of cancer heterogeneity and its variable responses.
The research team used a method to integrate cancer genomics data with the dynamics of biological networks for drug response prediction and to design of effective drug combination. It provides a computational framework for evaluating drug efficacies and synergistic effects by combining the attractor landscape analysis of a biological network with the genomic alteration profiles of cancer cells.
This technology can reduce the cost of drug development by predicting drug responses and help selecting more effective new drug targets in consideration of the overall cellular response landscape. It can also provide comprehensive insight into the mechanistic origin of variable drug responses. The patent technology can be applicable to designing more effective and cancer-specific combination therapies.
# Development of targeted anticancer drugs, genetic testing
Figure (a) The computational prediction of drug responses using attractor landscape analysis of network dynamics
▶ Highly Stretchable, Wearable Strain SensorBy Professor O Ok Park (Department of Chemical and Biomolecular Engineering)
Conventional materials for strain sensor are metals or semiconductors, but these materials show a limited range of strain. To improve the stretchability of conventional materials, several projects have been done using novel materials with a high aspect ratio; nevertheless, these projects encountered problems, including complex and expensive processes, poor scalable features, and low controllability of the sensitivity in the manufacturing step.
The research team used a layer-by-layer assembly technique to control the sensitivity of the sensor in a facile and inexpensive method. By using stretchable yarn as a substrate, the graphene strain sensor gained more stretchability.
Through the newly-patented technology, the graphene strain sensor can be fabricated using an all-solution process; therefore, the sensitivity of the sensor can be easily controlled with a repetitive cycle of the coating process. The size of this sensor can be controlled as well, because it depends only on the size of coated substrate.
# Wearable strain sensor, planar strain sensor
Figure (a) Nylon-covered rubber yarn showing linear relationship between the applied strain load and its resistance change
Figure (b) Wool yarn showing an inverse relation of resistance with the applied strain load
▶ Chip & Flash Memory Data Security DeviceBy Professor Yang-Kyu Choi (School of Electrical Engineering)
Using software-based security methods can lead to having problems related to the backtracking of a security function through reverse engineering, the replication of an input value, and the forgery and modification of software. These problems should not be neglected, especially as people are increasingly recognizing the importance of personal information.
To meet the growing demands for new security methods for constructing a more perfect security system, the research team developed a hardware-based security device as well as methods for a higher level of security in the era of IoTs. The principles of the technologies are based on nanotechnology, such as mechanical deformation in a nanowire, electrical degradation in a field-effect transistor (FET), and thermal data erasing stored in the charge trap layer in flash memory. Hence, the security states are extremely safe, compared with software-based security methods and cannot be reverse-engineered by unauthorized users.
This patented technology can be used to improve the security level of logic circuits and flash memory against unauthorized users.
# Financial businesses, the defense industry, private electronics including smartphones, tablets and PCs, electronics for missions in extreme environments
Figure (a) Application for a high level of security in a logic circuit
▶ A Bio-Healthcare Device for Neuroimaging
By Professor Hyeonmin Bae (School of Electrical Engineering)There are no portable brain imaging devices and, as a result, brain diseases are often diagnosed after irreversible symptoms appeared. This can also be linked to an increase in social expenditures as a society ages.
A near-infrared spectroscopy neuroimaging device for functional brain imaging, NIRSIT, utilizes light to detect hemodynamic changes in cerebral blood flow and visualizes brain activation regions in the prefrontal area of the brain in real time.
Unlike any other existing brain imaging devices (i.e. fMRI and conventional fNIRS), NIRSIT has improved its spatial resolution while maintaining complete portability.
Furthermore, NIRSIT is probably the one and only portable and wireless NIRS device, designed to be used for brain research and clinical purposes. A software application allows the raw data extracted from the hemodynamic changes in the brain to be shown in real time on a tablet wirelessly connected to NIRSIT.
Thanks to its easy-to-use features and user-friendly design, both in hardware and in software, NIRSIT will surely set a new paradigm in the brain research and healthcare fields.
# Concussion analysis, wearable stroke monitoring, CPR monitoring, Alzheimer’s disease, neuro rehabilitation, determination of brain death
Figure (a) Image of NIRSIT, Figure (b) Neuroimaging using NIRSIT
▶ Technology for Virtual Creatures with Digitally-Emotional DNA of UsersBy Professor Jong-Hwan Kim (School of Electrical Engineering)
Currently, a large number of IT companies around the world are trying to develop a system that can offer active and emotional services and the interface method is one of the most important issues.
Although most of the existing software agents are equipped with virtual faces and voices, they do not possess a personality similar to humans. Having various personalities, like human beings, can be a charming point for users, which then leads them to have higher satisfaction with the product.
Dr. Kim’s research team developed Darwin C (Digital Agent Reconstruction with Intelligence and Natural Character), a digital agent software that provides an optimized emotional service based on personal big data, such as the user’s conversations, locations, photos, music, etc., collected from smart devices.
With this technology, the digital DNAs of a user (i.e. appearance, voice, and personality DNA) is extracted from personal data stored on various smart devices. Based on the extracted digital DNA, a 3-D software agent can be formed in a smartphone, which characterizes an individual that the user hopes to meet, such as parents, spouse, grandchild, or a celebrity.
The software agents will be expanded from Android devices to home appliances. The team expected that this technology can help customers who want to understand more about a friend or form and maintain interpersonal relations.
# Entertainment, hardware robots for education, healthcare curing depression and loneliness
Figure (a) Overview of the DarwinC technology, Figure (b) Structure of digital DNA
▶ Laser-Integrated Precision Metrological System Technology for Smart Factories By Professor Seung-woo Kim (Department of Mechanical Engineering)
In optical distance metrology, the time-of-flight method of using light pulses permits measuring distances over extensive ranges. However, the measurement precision reaches just a few tens of millimeters at most, mainly because the responsivity of the photodetectors available today is limited to the picosecond range. In addition, one device can measure only one target. For these reasons, a novel technology was devised to overcome the traditional limits of time-of-flight measurement.
This patented technology uses a highly precise, laser-integrated distance measurement system for diagnosing large machines and smart factories. This technology was devised to handle the status (e.g. position, 3-D coordinate, and thermal deformation) of multiple targets simultaneously. It is called the multi-target distance meter (MDM) and was constructed by combining a nonlinear optical crystal with a pair of femtosecond lasers.
This technology is able to measure the distances to multiple targets with a single piece of equipment, and it can easily extend the number of targets by just adding beam-splitting devices. Not only does the technology help by reducing cost and complexity, it also enables real-time quality control in the manufacturing industry.
# Real-time on-axis position inspection of a multiple-lens assembly, long-term thermal displacement monitoring of a large, precise machine, 3-D motion control of a mobile vehicle
Figure (a) Conceptual image of smart factory monitoring using laser-integrated precision metrological system technology
▶ SLAM Technology for Autonomous Robot Navigation in a Dynamic Indoor/Outdoor EnvironmentBy Professor Hyun Myung (Department of Civil & Environmental Engineering)
Dr. Myung’s research team developed SLAM (Simultaneous Localization and Mapping) technology for autonomous robot navigation in dynamic indoor/outdoor environments. Two methods were applied to this technology: a hierarchical graph structure-based 3-D high resolution map building method using a low-cost 2D laser scanner and a magnetic field-based localization method for feature-poor environments.
Existing technology required expensive sensors for outdoor environment. The localization and mapping technique were also not very accurate, especially in dynamic environments. The team wanted to provide robust SLAM in low and high dynamic object environments using the fusion of low-cost sensors, such as magnetics, 2-D LiDAR, and camera sensors.
Through this technology, the accuracy of localization and mapping could be increased to within 10cm, using low-cost sensors. Also, it facilitates localization and mapping even in feature-poor environments.
# Autonomous robot navigation in warehouses, autonomous navigation of self-driving cars, autonomous navigation of AGVs (Automated Guided Vehicles) in smart factories
Figure (a) Built outdoor 3-D mappring using a mobile robot with tilted 2-D LiDAR sensor, Figure (b) Mobile robot system for GPS-less mappring
▶ Technology for Optimizing 5G Beamforming ICBy Songcheol Hong (School of Electrical Engineering)
Dr. Hong’s team introduced a new structure for low-power, subminiature, and highly-linear beamforming IC technology. The patent used in this technology reduced the chip size and the direct current (DC) power dissipations drastically, allowing it to make mmWave beamforming antennas.
Beam-forming technology has emerged as an important area in the field of 5G communications and radar systems. It facilitates communication and signal detection with very low RF power.
The patents can be applied to 5G communication beam-forming ICs and antenna modules in mobile terminals, base stations and terminals in the automotive field. Moreover, they can be used in various mmWave radar systems for automobiles, drones, human computer interfaces, and indoor positioning.
# 5G V2X, IoTs, virtual reality
Figure (a) Active phased array system
▶ Beam Division Multiple Access TechnologyBy Professor Dong Ho Cho (School of Electrical Engineering)
Using a 5G network, a communication infrastructure for supporting high-speed, real-time services requires new technologies that enable 4x4 MIMO transmissions within beam-based wireless systems in a new frequency band and improves spectral efficiency more than ten times compared to LTE in domestic and overseas mobile communication carriers and related industries.
P2BDMA, a pattern or polarization beam division multiple access technology, is a core technology for addressing this demand for 5G networks as it enables 4x4 MIMO transmissions in mmWave frequency bands by utilizing the pattern polarization characteristic of radio waves.
The research team upgraded BDMA technology in which the same frequency resource is reused in more than two spaces by using beamforming. This technology increases the degree of freedom (DOF) of wireless communication channels, and thereby improves the achievable data transmission rate by employing multiple pattern/polarization antennas in the conventional BDMA system. The P2BDMA technique has the advantage of eliminating the frequency shortage problem and increasing the transmission speed while using the wide frequency band in a more efficient manner.
The team expects that this technology will alleviate the frequency shortage problem and CAPEX/OPEX of domestic mobile telecommunication companies, support an increase in sales for related equipment makers to make it internationally competitive, and further play a central role in providing high-speed transmission rates to a large number of IoT devices in the future IoT era.
# Autonomous vehicle, communication infrastructure, mobile access system
Figure (a) Concept of P2BDMA technology
2017.08.30 View 16340 -
Multi-Device Mobile Platform for App Functionality Sharing
Case 1. Mr. Kim, an employee, logged on to his SNS account using a tablet PC at the airport while traveling overseas. However, a malicious virus was installed on the tablet PC and some photos posted on his SNS were deleted by someone else.
Case 2. Mr. and Mrs. Brown are busy contacting credit card and game companies, because his son, who likes games, purchased a million dollars worth of game items using his smartphone.
Case 3. Mr. Park, who enjoys games, bought a sensor-based racing game through his tablet PC. However, he could not enjoy the racing game on his tablet because it was not comfortable to tilt the device for game control.
The above cases are some of the various problems that can arise in modern society where diverse smart devices, including smartphones, exist. Recently, new technology has been developed to easily solve these problems. Professor Insik Shin from the School of Computing has developed ‘Mobile Plus,’ which is a mobile platform that can share the functionalities of applications between smart devices.
This is a novel technology that allows applications to easily share their functionalities without needing any modifications. Smartphone users often use Facebook to log in to another SNS account like Instagram, or use a gallery app to post some photos on their SNS. These examples are possible, because the applications share their login and photo management functionalities.
The functionality sharing enables users to utilize smartphones in various and convenient ways and allows app developers to easily create applications. However, current mobile platforms such as Android or iOS only support functionality sharing within a single mobile device. It is burdensome for both developers and users to share functionalities across devices because developers would need to create more complex applications and users would need to install the applications on each device.
To address this problem, Professor Shin’s research team developed platform technology to support functionality sharing between devices. The main concept is using virtualization to give the illusion that the applications running on separate devices are on a single device. They succeeded in this virtualization by extending a RPC (Remote Procedure Call) scheme to multi-device environments.
This virtualization technology enables the existing applications to share their functionalities without needing any modifications, regardless of the type of applications. So users can now use them without additional purchases or updates. Mobile Plus can support hardware functionalities like cameras, microphones, and GPS as well as application functionalities such as logins, payments, and photo sharing. Its greatest advantage is its wide range of possible applications.
Professor Shin said, "Mobile Plus is expected to have great synergy with smart home and smart car technologies. It can provide novel user experiences (UXs) so that users can easily utilize various applications of smart home/vehicle infotainment systems by using a smartphone as their hub."
This research was published at ACM MobiSys, an international conference on mobile computing that was hosted in the United States on June 21.
Figure1. Users can securely log on to SNS accounts by using their personal devices
Figure 2. Parents can control impulse shopping of their children.
Figure 3. Users can enjoy games more and more by using the smartphone as a controller.
2017.08.09 View 10610 -
Innovative Nanosensor for Disease Diagnosis
(Figure 1. Sensing Device)
(Figure 2. Protein templating route)
Breath pattern recognition is a futuristic diagnostic platform. Simple characterizing target gas concentrations of human exhaled breath will lead to diagnose of the disease as well as physical condition.
A research group under Prof. Il-Doo Kim in the Department of Materials Science has developed diagnostic sensors using protein-encapsulated nanocatalysts, which can diagnose certain diseases by analyzing human exhaled breath. This technology enables early monitoring of various diseases through pattern recognition of biomarker gases related to diseases in human exhalation.
The protein-templated catalyst synthesis route is very simple and versatile for producing not only a single component of catalytic nanoparticles, but also diverse heterogeneous intermetallic catalysts with sizes less than 3 nm. The research team has developed ever more sensitive and selective chemiresistive sensors that can potentially diagnose specific diseases by analyzing exhaled breath gases.
The results of this study, which were contributed by Dr. Sang-Joon Kim and Dr. Seon-Jin Choi as first authors were selected as the cover-featured article in the July issue of 'Accounts of Chemical Research,' an international journal of the American Chemical Society.
In human breath, diverse components are found including water vapor, hydrogen, acetone, toluene, ammonia, hydrogen sulfide, and carbon monoxide, which are more excessively exhaled from patients. Some of these components are closely related to diseases such as asthma, lung cancer, type 1 diabetes mellitus, and halitosis.
Breath analysis for disease diagnosis started from capturing exhaled breaths in a Tedlar bag and subsequently the captured breath gases were injected into a miniaturized sensor system, similar to an alcohol detector. It is possible to analyze exhaled breath very rapidly with a simple analyzing process. The breath analysis can detect trace changes in exhaled breath components, which contribute to early diagnosis of diseases.
However, technological advances are needed to accurately analyze gases in the breath, which occur at very low levels, from 1 ppb to 1 ppm. In particular, it has been a critical challenge for chemiresistive type chemical sensors to selectively detect specific biomarkers in thousands of interfering gases including humid vapor.
Conventionally, noble metallic catalysts such as platinum and palladium have been functionalized onto metal oxide sensing layers. However, the gas sensitivity was not enough to detect ppb-levels of biomarker species in exhaled breath.
To overcome the current limitations, the research team utilized nanoscale protein (apoferritin) in animals as sacrificial templates. The protein templates possess hollow nanocages at the core site and various alloy catalytic nanoparticles can be encapsulated inside the protein nanocages.
The protein nanocages are advantageous because a nearly unlimited number of material compositions in the periodic table can be assembled for the synthesis of heterogeneous catalytic nanoparticles. In addition, intermetallic nanocatalysts with a controlled atomic ratio of two different elements can be achieved using the protein nanocages, which is an innovative strategy for finding new types of catalysts. For example, highly efficient platinum-based catalysts can be synthesized, such as platinum-palladium (PtPd), platinum-nickel (PtNi), platinum-ruthenium (PtRu), and platinum-yttrium (PtY).
The research team developed outstanding sensing layers consisting of metal oxide nanofibers functionalized by the heterogeneous catalysts with large and highly-porous surface areas, which are especially optimized for selective detection of specific biomarkers. The biomarker sensing performance was improved approximately 3~4-fold as compared to the conventional single component of platinum and palladium catalysts-loaded nanofiber sensors. In particular, 100-fold resistance transitions toward acetone (1 ppm) and hydrogen sulfide (1 ppm) were observed in exhaled breath sensors using the heterogeneous nanocatalysts, which is the best performance ever reported in literature.
The research team developed a disease diagnosis platform that recognizes individual breathing patterns by using a multiple sensor array system with diverse sensing layers and heterogeneous catalysts, so that the people can easily identify health abnormalities. Using a 16-sensor array system, physical conditions can be continuously monitored by analyzing concentration changes of biomarkers in exhaled breath gases.
Prof. Kim said, “New types of heterogeneous nanocatalysts were synthesized using protein templates with sizes around 2 nm and functionalized on various metal oxide nanofiber sensing layers. The established sensing libraries can detect biomarker species with high sensitivity and selectivity.” He added, “the new and innovative breath gas analysis platform will be very helpful for reducing medical expenditures and continuous monitoring of physical conditions”
Patents related to this technology were licensed to two companies in March and June this year.
2017.07.19 View 11294