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KAIST Develops Janus-like Metasurface Technology that Acts According to the Direction of Light
Metasurface technology is an advanced optical technology that is thinner, lighter, and capable of precisely controlling light through nanometer-sized artificial structures compared to conventional technologies. KAIST researchers have overcome the limitations of existing metasurface technologies and successfully designed a Janus metasurface capable of perfectly controlling asymmetric light transmission. By applying this technology, they also proposed an innovative method to significantly enhance security by only decoding information under specific conditions.
KAIST (represented by President Kwang Hyung Lee) announced on the 15th of October that a research team led by Professor Jonghwa Shin from the Department of Materials Science and Engineering had developed a Janus metasurface capable of perfectly controlling asymmetric light transmission.
Asymmetric properties, which react differently depending on the direction, play a crucial role in various fields of science and engineering. The Janus metasurface developed by the research team implements an optical system capable of performing different functions in both directions.
Like the Roman god Janus with two faces, this metasurface shows entirely different optical responses depending on the direction of incoming light, effectively operating two independent optical systems with a single device (for example, a metasurface that acts as a magnifying lens in one direction and as a polarized camera in the other). In other words, by using this technology, it's possible to operate two different optical systems (e.g., a lens and a hologram) depending on the direction of the light.
This achievement addresses a challenge that existing metasurface technologies had not resolved. Conventional metasurface technology had limitations in selectively controlling the three properties of light—intensity, phase, and polarization—based on the direction of incidence.
The research team proposed a solution based on mathematical and physical principles, and succeeded in experimentally implementing different vector holograms in both directions. Through this achievement, they showcased a complete asymmetric light transmission control technology.
< Figure 1. Schematics of a device featuring asymmetric transmission. a) Device operating as a magnifying lens for back-side illumination. b) Device operating as a polarization camera for front-side illumination. >
Additionally, the research team developed a new optical encryption technology based on this metasurface technology. By using the Janus metasurface, they implemented a vector hologram that generates different images depending on the direction and polarization state of incoming light, showcasing an optical encryption system that significantly enhances security by allowing information to be decoded only under specific conditions.
This technology is expected to serve as a next-generation security solution, applicable in various fields such as quantum communication and secure data transmission.
Furthermore, the ultra-thin structure of the metasurface is expected to significantly reduce the volume and weight of traditional optical devices, contributing greatly to the miniaturization and lightweight design of next-generation devices.
< Figure 2. Experimental demonstration of Janus vectorial holograms. With front illuminations, vector images of the butterfly and the grasshopper are created, and with the back-side illuminations, vector images of the ladybug and the beetle are created. >
Professor Jonghwa Shin from the Department of Materials Science and Engineering at KAIST stated, "This research has enabled the complete asymmetric transmission control of light’s intensity, phase, and polarization, which has been a long-standing challenge in optics. It has opened up the possibility of developing various applied optical devices." He added, "We plan to continue developing optical devices that can be applied to various fields such as augmented reality (AR), holographic displays, and LiDAR systems for autonomous vehicles, utilizing the full potential of metasurface technology."
This research, in which Hyeonhee Kim (a doctoral student in the Department of Materials Science and Engineering at KAIST) and Joonkyo Jung participated as co-first authors, was published online in the international journal Advanced Materials and is scheduled to be published in the October 31 issue. (Title of the paper: "Bidirectional Vectorial Holography Using Bi-Layer Metasurfaces and Its Application to Optical Encryption")
The research was supported by the Nano Materials Technology Development Program and the Mid-Career Researcher Program of the National Research Foundation of Korea.
2024.10.15 View 1098 -
KAIST Succeeds in the Real-time Observation of Organoids using Holotomography
Organoids, which are 3D miniature organs that mimic the structure and function of human organs, play an essential role in disease research and drug development. A Korean research team has overcome the limitations of existing imaging technologies, succeeding in the real-time, high-resolution observation of living organoids.
KAIST (represented by President Kwang Hyung Lee) announced on the 14th of October that Professor YongKeun Park’s research team from the Department of Physics, in collaboration with the Genome Editing Research Center (Director Bon-Kyoung Koo) of the Institute for Basic Science (IBS President Do-Young Noh) and Tomocube Inc., has developed an imaging technology using holotomography to observe live, small intestinal organoids in real time at a high resolution.
Existing imaging techniques have struggled to observe living organoids in high resolution over extended periods and often required additional treatments like fluorescent staining.
< Figure 1. Overview of the low-coherence HT workflow. Using holotomography, 3D morphological restoration and quantitative analysis of organoids can be performed. In order to improve the limited field of view, which is a limitation of the microscope, our research team utilized a large-area field of view combination algorithm and made a 3D restoration by acquiring multi-focus holographic images for 3D measurements. After that, the organoids were compartmentalized to divide the parts necessary for analysis and quantitatively evaluated the protein concentration measurable from the refractive index and the survival rate of the organoids. >
The research team introduced holotomography technology to address these issues, which provides high-resolution images without the need for fluorescent staining and allows for the long-term observation of dynamic changes in real time without causing cell damage.
The team validated this technology using small intestinal organoids from experimental mice and were able to observe various cell structures inside the organoids in detail. They also captured dynamic changes such as growth processes, cell division, and cell death in real time using holotomography.
Additionally, the technology allowed for the precise analysis of the organoids' responses to drug treatments, verifying the survival of the cells.
The researchers believe that this breakthrough will open new horizons in organoid research, enabling the greater utilization of organoids in drug development, personalized medicine, and regenerative medicine.
Future research is expected to more accurately replicate the in vivo environment of organoids, contributing significantly to a more detailed understanding of various life phenomena at the cellular level through more precise 3D imaging.
< Figure 2. Real-time organoid morphology analysis. Using holotomography, it is possible to observe the lumen and villus development process of intestinal organoids in real time, which was difficult to observe with a conventional microscope. In addition, various information about intestinal organoids can be obtained by quantifying the size and protein amount of intestinal organoids through image analysis. >
Dr. Mahn Jae Lee, a graduate of KAIST's Graduate School of Medical Science and Engineering, currently at Chungnam National University Hospital and the first author of the paper, commented, "This research represents a new imaging technology that surpasses previous limitations and is expected to make a major contribution to disease modeling, personalized treatments, and drug development research using organoids."
The research results were published online in the international journal Experimental & Molecular Medicine on October 1, 2024, and the technology has been recognized for its applicability in various fields of life sciences. (Paper title: “Long-term three-dimensional high-resolution imaging of live unlabeled small intestinal organoids via low-coherence holotomography”)
This research was supported by the National Research Foundation of Korea, KAIST Institutes, and the Institute for Basic Science.
2024.10.14 View 944 -
KAIST Changes the Paradigm of Drug Discovery with World's First Atomic Editing
In pioneering drug development, the new technology that enables the easy and rapid editing of key atoms responsible for drug efficacy has been regarded as a fundamental and "dream" technology, revolutionizing the process of discovering potential drug candidates. KAIST researchers have become the first in the world to successfully develop single-atom editing technology that maximizes drug efficacy.
On October 8th, KAIST (represented by President Kwang-Hyung Lee) announced that Professor Yoonsu Park’s research team from the Department of Chemistry successfully developed technology that enables the easy editing and correction of oxygen atoms in furan compounds into nitrogen atoms, directly converting them into pyrrole frameworks, which are widely used in pharmaceuticals.
< Image. Conceptual image illustrating the main idea of the research >
This research was published in the prestigious scientific journal Science on October 3rd under the title "Photocatalytic Furan-to-Pyrrole Conversion."
Many drugs have complex chemical structures, but their efficacy is often determined by a single critical atom. Atoms like oxygen and nitrogen play a central role in enhancing the pharmacological effects of these drugs, particularly against viruses.
This phenomenon, where the introduction of specific atoms into a drug molecule dramatically affects its efficacy, is known as the "Single Atom Effect." In leading-edge drug development, discovering atoms that maximize drug efficacy is key.
However, evaluating the Single Atom Effect has traditionally required multi-step, costly synthesis processes, as it has been difficult to selectively edit single atoms within stable ring structures containing oxygen or nitrogen.
Professor Park’s team overcame this challenge by introducing a photocatalyst that uses light energy. They developed a photocatalyst that acts as a “molecular scissor,” freely cutting and attaching five-membered rings, enabling single-atom editing at room temperature and atmospheric pressure—a world first.
The team discovered a new reaction mechanism in which the excited molecular scissor removes oxygen from furan via single-electron oxidation and then sequentially adds a nitrogen atom.
Donghyeon Kim and Jaehyun You, the study's first authors and candidates in KAIST’s integrated master's and doctoral program in the Department of Chemistry, explained that this technique offers high versatility by utilizing light energy to replace harsh conditions. They further noted that the technology enables selective editing, even when applied to complex natural products or pharmaceuticals. Professor Yoonsu Park, who led the research, remarked, "This breakthrough, which allows for the selective editing of five-membered organic ring structures, will open new doors for building libraries of drug candidates, a key challenge in pharmaceuticals. I hope this foundational technology will be used to revolutionize the drug development process."
The significance of this research was highlighted in the Perspective section of Science, a feature where a peer scientist of prominence outside of the project group provides commentary on an impactful research.
This research was supported by the National Research Foundation of Korea’s Creative Research Program, the Cross-Generation Collaborative Lab Project at KAIST, and the POSCO Science Fellowship of the POSCO TJ Park Foundation.
2024.10.11 View 1496 -
KAIST Develops Stretchable Displays Featuring 25% Expansion Without Image Distortion
Stretchable displays, praised for their spatial efficiency, design flexibility, and human-like flexibility, are seen as the next generation of display technology. A team of Korean researchers has developed a stretchable display that can expand by 25% while maintaining clear image quality without distortion. It can also stretch and contract up to 5,000 times at 15% expansion without any performance degradation, making it the first deformation-free stretchable display with a negative Poisson's ratio* developed in Korea.
*Poisson’s ratio of -1: A ratio where both width and length stretch equally, expressed as a negative value. A positive Poisson's ratio represents the ratio where horizontal stretching leads to vertical contraction, which is the case for most materials.
KAIST (represented by President Kwang-Hyung Lee) announced on the 20th of August that a research team led by Professor Byeong-Soo Bae of the Department of Materials Science and Engineering (Director of the Wearable Platform Materials Technology Center) , in collaboration with the Korea Institute of Machinery & Materials (President Seoghyeon Ryu), successfully developed a stretchable display substrate that suppresses image distortion through omnidirectional stretchability.
Currently, most stretchable displays are made with highly elastic elastomer* materials, but these materials possess a positive Poisson's ratio, causing unavoidable image distortion when the display is stretched.
*Elastomer: A polymer with elasticity similar to rubber.
To address this, the introduction of auxetic* meta-structures has been gaining attention. Unlike conventional materials, auxetic structures have a unique 'negative Poisson's ratio,' expanding in all directions when stretched in just one direction. However, traditional auxetic structures contain many empty spaces, limiting their stability and usability in display substrates.
*Auxetic structure: A special geometric structure that exhibits a negative Poisson's ratio.
To tackle the issue of image distortion, Professor Bae's research team developed a method to create a seamless surface for the auxetic meta-structure, achieving the ideal negative Poisson's ratio of -1 and overcoming the biggest challenge in auxetic meta-structures.
To overcome the second issue of elastic modulus*, the team inserted a textile made of glass fiber bundles with a diameter of just 25 micrometers (a quarter of the thickness of human hair) into the elastomer material. They then filled the empty spaces with the same elastomer, creating a flat and stable integrated film without gaps.
*Elastic Modulus: The ratio that indicates the extent of deformation when force is applied to a material. A higher elastic modulus means that the material is less likely to deform under force.
The research team theoretically identified that the difference in elasticity between the auxetic structure and the elastomer material directly influences the negative Poisson's ratio and successfully achieved an elasticity difference of over 230,000 times, producing a film with a Poisson's ratio of -1, the theoretical limit.
< Figure 2. Deformation of S-AUX film. a) Configurations and visualized principal strain distribution of the optimized S-AUX film at various strain rates. b) Biaxial stretching image. While pristine elastomer shrinks in the directions that were not stretched, S-AUX film developed in this study expands in all directions simultaneously while maintaining its original shape. >
Professor Byeong-Soo Bae, who led the study, explained, "Preventing image distortion using auxetic structures in stretchable displays is a core technology, but it has faced challenges due to the many empty spaces in the surface, making it difficult to use as a substrate. This research outcome is expected to significantly accelerate commercialization through high-resolution, distortion-free stretchable display applications that utilize the entire surface."
This study, co-authored by Dr. Yung Lee from KAIST’s Department of Materials Science and Engineering and Dr. Bongkyun Jang from the Korea Institute of Machinery & Materials, was published on August 20th in the international journal Nature Communications under the title "A seamless auxetic substrate with a negative Poisson's ratio of –1".
The research was supported by the Wearable Platform Materials Technology Center at KAIST, the Korea Institute of Machinery & Materials, and LG Display.
< Figure 3. Structural configuration of the distortion-free display components on the S-AUX film and a contour image of a micro-LED chip transferred onto the S-AUX film. >
< Figure 4. Schematic illustrations and photographic images of the S-AUX film-based image: distortion-free display in its stretched state and released state. >
2024.09.20 View 2179 -
Professor Jimin Park and Dr. Inho Kim join the ranks of the 2024 "35 Innovators Under 35" by the MIT Technology Review
< (From left) Professor Jimin Park of the Department of Chemical and Biomolecular Engineering and Dr. Inho Kim, a graduate of the Department of Materials Science and Engineering >
KAIST (represented by President Kwang-Hyung Lee) announced on the 13th of September that Professor Jimin Park from KAIST’s Department of Chemical and Biomolecular Engineering and Dr. Inho Kim, a graduate from the Department of Materials Science and Engineering (currently a postdoctoral researcher at Caltech), were selected by the MIT Technology Review as the 2024 "35 Innovators Under 35”.
The MIT Technology Review, first published in 1899 by the Massachusetts Institute of Technology, is the world’s oldest and most influential magazine on science and technology, offering in-depth analysis across various technology fields, expanding knowledge and providing insights into cutting-edge technology trends.
Since 1999, the magazine has annually named 35 innovators under the age of 35, recognizing young talents making groundbreaking contributions in modern technology fields. The recognition is globally considered a prestigious honor and a dream for young researchers in the science and technology community.
< Image 1. Introduction for Professor Jimin Park at the Meet 35 Innovators Under 35 Summit 2024 >
Professor Jimin Park is developing next-generation bio-interfaces that link artificial materials with living organisms, and is engaged in advanced research in areas such as digital healthcare and carbon-neutral compound manufacturing technologies. In 2014, Professor Park was also recognized as one of the ‘Asia Pacific Innovators Under 35’ by the MIT Technology Review, which highlights young scientists in the Asia-Pacific region.
Professor Park responded, “It’s a great honor to be named as one of the young innovators by the MIT Technology Review, a symbol of innovation with a long history. I will continue to pursue challenging, interdisciplinary research to develop next-generation interfaces that seamlessly connect artificial materials and living organisms, from atomic to system levels.”
< Image 2. Introduction for Dr. Inho Kim as the 2024 Innovator of Materials Science for 35 Innovators Under 35 >
Dr. Inho Kim, who earned his PhD from KAIST in 2020 under the supervision of Professor Sang Ouk Kim from the Department of Materials Science and Engineering, recently succeeded in developing a new artificial muscle using composite fibers. This new material is considered the most human-like muscle ever reported in scientific literature, while also being 17 times stronger than natural human muscle.
Dr. Kim is researching the application of artificial muscle fibers in next-generation wearable assistive devices that move more naturally, like humans or animals, noting that the fibers are lightweight, flexible, and exhibit conductivity during contraction, enabling real-time feedback. Recognized for this potential, Dr. Inho Kim was named one of the '35 Innovators Under 35' this year, making him the first researcher to win the honor with the research conducted at KAIST and a PhD earned from Korea.
Dr. Kim stated, “I aim to develop robots using these new materials that can replace today’s expensive and heavy exoskeleton suits by eliminating motors and rigid frames. This will significantly reduce costs and allow for better customization, making cutting-edge technology more accessible to those who need it most, like children with cerebral palsy.”
2024.09.13 View 1726 -
KAIST ISSS Research Session Captivates 150↑ International Scholars, Achieve Major Success
< Photo. Scholars gatheres for NRF Information Session at Chung Keun Mo Hall >
KAIST’s International Office, headed by Vice President Soyoung Kim, successfully organized the ‘NRF Information Session for International Scholars’ on September 11, 2024, in collaboration with the National Research Foundation of Korea (NRF).
The event was held at KAIST’s main campus to enourage the international scholar’s active participation in research projects and support their establishment of stable research environment and integration into Korea’s academic community by introducing NRF’s key research programs.
Divided into two main segments – science and engineering, and humanities and social sciences – the session attracted approximately 150 international faculty and researchers from 23 universities across the nation.
The event commenced with a keynote address by Vice President Soyoung Kim, followed by a presentation from Dr. Seol Min of the National Research Foundation, who highlighted basic research initiatives in the science and technology sector. Subsequently, Professor Daniel Martin from the Digital Humanities and Social Sciences Department and Professor Thomas Steinberger from the Department of Business and Technology Management presented practical research project support case studies, sharing invaluable insights gained from their domestic research experiences.
Following the information session, participants engaged in a networking event, where researchers involved in major R&D projects exchanged insights and discussed their ongoing research initiatives.
An international professor remarked, “My understanding of NRF’s research programs for international researchers has broadened considerably. I am now more inclined to actively participate in projects organized by NRF in the future.”
Vice President Kim expressed her aspiration that the event would address the challenges faced by researchers and offer essential support to those engaged in research projects. “We will stay attuned to the needs of the research community and work towards creating a more supportive research environment,” said the VP.
Meanwhile, KAIST hosts a distinguished faculty comprising 134 professors from 22 countries and 71 researchers representing 23 nations, all contributing to groundbreaking academic achievements. Additionally, KAIST is home to over 1,000 international students from more than 100 countries, actively pursuing their studies. This diverse composition of global talent reinforces KAIST's position as a leading international hub for research and education.
2024.09.13 View 1239 -
KAIST finds ways for Bacteria to produce PET-like materials
Among various eco-friendly polymers, polyhydroxyalkanoates (PHA) stand out for their excellent biodegradability and biocompatibility. They decompose naturally in soil and marine environments and are used in applications such as food packaging and medical products. However, natural PHA produced to date has faced challenges meeting various physical property requirements, such as durability and thermal stability, and has been limited in its commercial application due to low production concentrations. In light of this, KAIST researchers have recently developed a technology that could play a crucial role in solving the environmental pollution problem caused by plastics.
KAIST (represented by President Kwang-Hyung Lee) announced on August 26th that a research team led by Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering, including Dr. Youngjoon Lee and master's student Minju Kang, has successfully developed a microbial strain that efficiently produces aromatic polyester* using systems metabolic engineering.
※ Aromatic polyester: A polymer containing aromatic compounds (specific carbon ring structures like benzene) and ester bonds.
In this study, the research team used metabolic engineering to enhance the metabolic flux of the biosynthetic pathway for the aromatic monomer phenyllactate (PhLA) in E. coli. They manipulated the metabolic pathway to increase the polymer fraction accumulated within the cells and employed computer simulations to predict the structure of PHA synthase and improve the enzyme based on the structure-function relationship.
Through subsequent fermentation optimization, the team achieved the world’s highest concentration (12.3±0.1 g/L) for the efficient production of poly (PhLA) and successfully produced polyester through a 30L scale fed-batch fermentation, demonstrating the possibility of industrial-level production. The produced aromatic polyesters showed enhanced thermal properties, improved mechanical properties, and potential for use as drug delivery carriers.
< Figure 1. Development schematics of aromatic polyester producing microorganisms >
The research team also demonstrated that an exogenous phasin protein* plays a crucial role in increasing the intracellular polymer accumulation fraction, which is directly related to the economic feasibility and efficiency of non-natural PHA production. They improved PHA synthase using a rational enzyme design approach, predicting the three-dimensional structure of the enzyme through homology modeling (a method of predicting the three-dimensional structure of a new protein based on the structure of similar proteins) followed by molecular docking simulations (simulations that predict how well a monomer can bind to an enzyme) and molecular dynamics simulations (simulations that predict how molecules move and interact over time) to upgrade the enzyme into a mutant enzyme with enhanced monomer polymerization efficiency.
※ Exogenous phasin protein: Phasin is a protein related to PHA production, interacting with the cytoplasmic environment on the surface of granules of PHA, and playing a role in polymer accumulation and controlling the number and size of granules. In this study, genes encoding phasin proteins derived from various natural PHA-producing microorganisms were selected and introduced.
Dr. Youngjoon Lee, co-first author of the paper, explained, "The significance of this study lies in the fact that we have achieved the world's highest concentration of microbial-based aromatic polyester production using eco-friendly materials and methods. This technology is expected to play a crucial role in addressing the environmental pollution caused by plastics." Distinguished Professor Sang Yup Lee added, "This study, which presents various strategies for the high-efficiency production of useful polymers via systems metabolic engineering, is expected to make a significant contribution to solving climate change issues, particularly the recent plastic problem."
< Figure 2. Detailed development strategy for aromatic polyester producing microorganisms >
The research findings were published on August 21st in Trends in Biotechnology, published by Cell, an international academic journal.
※ Paper Title: “Microbial production of an aromatic homopolyester”
※ Author Information: Youngjoon Lee (KAIST, co-first author), Minju Kang (KAIST, co-first author), Woo Dae Jang (KAIST, second author), So Young Choi (KAIST, third author), Jung Eun Yang (KAIST, fourth author), Sang Yup Lee (KAIST, corresponding author), totaling six authors.
This research was supported by the "Development of Next-Generation Biorefinery Platform Technologies for Leading the Bio-based Chemicals Industry" project led by Distinguished Professor Sang Yup Lee at KAIST, under the eco-friendly chemical technology development project aimed at substituting petroleum, funded by the Ministry of Science and ICT. It was also supported by the "Development of Platform Technology for the Production of Novel Aromatic Bioplastic Using Microbial Cell Factories" project (Project Leader: Si Jae Park, Ewha Woman’s University).
2024.08.28 View 1981 -
KAIST presents strategies for Holotomography in advanced bio research
Measuring and analyzing three-dimensional (3D) images of live cells and tissues is considered crucial in advanced fields of biology and medicine. Organoids, which are 3D structures that mimic organs, are particular examples that significantly benefits 3D live imaging. Organoids provide effective alternatives to animal testing in the drug development processes, and can rapidly determine personalized medicine. On the other hand, active researches are ongoing to utilize organoids for organ replacement.
< Figure 1. Schematic illustration of holotomography compared to X-ray CT. Similar to CT, they share the commonality of measuring the optical properties of an unlabeled specimen in three dimensions. Instead of X-rays, holotomography irradiates light in the visible range, and provides refractive index measurements of transparent specimens rather than absorptivity. While CT obtains three-dimensional information only through mechanical rotation of the irradiating light, holotomography can replace this by applying wavefront control technology in the visible range. >
Organelle-level observation of 3D biological specimens such as organoids and stem cell colonies without staining or preprocessing holds significant implications for both innovating basic research and bioindustrial applications related to regenerative medicine and bioindustrial applications.
Holotomography (HT) is a 3D optical microscopy that implements 3D reconstruction analogous to that of X-ray computed tomography (CT). Although HT and CT share a similar theoretical background, HT facilitates high-resolution examination inside cells and tissues, instead of the human body. HT obtains 3D images of cells and tissues at the organelle level without chemical or genetic labeling, thus overcomes various challenges of existing methods in bio research and industry. Its potential is highlighted in research fields where sample physiology must not be disrupted, such as regenerative medicine, personalized medicine, and infertility treatment.
< Figure 2. Label-free 3D imaging of diverse live cells. Time-lapse image of Hep3B cells illustrating subcellular morphology changes upon H2O2 treatment, followed by cellular recovery after returning to the regular cell culture medium. >
This paper introduces the advantages and broad applicability of HT to biomedical researchers, while presenting an overview of principles and future technical challenges to optical researchers. It showcases various cases of applying HT in studies such as 3D biology, regenerative medicine, and cancer research, as well as suggesting future optical development. Also, it categorizes HT based on the light source, to describe the principles, limitations, and improvements of each category in detail. Particularly, the paper addresses strategies for deepening cell and organoid studies by introducing artificial intelligence (AI) to HT.
Due to its potential to drive advanced bioindustry, HT is attracting interest and investment from universities and corporates worldwide. The KAIST research team has been leading this international field by developing core technologies and carrying out key application researches throughout the last decade.
< Figure 3. Various types of cells and organelles that make up the imaging barrier of a living intestinal organoid can be observed using holotomography. >
This paper, co-authored by Dr. Geon Kim from KAIST Research Center for Natural Sciences, Professor Ki-Jun Yoon's team from the Department of Biological Sciences, Director Bon-Kyoung Koo's team from the Institute for Basic Science (IBS) Center for Genome Engineering, and Dr. Seongsoo Lee's team from the Korea Basic Science Institute (KBSI), was published in 'Nature Reviews Methods Primers' on the 25th of July. This research was supported by the Leader Grant and Basic Science Research Program of the National Research Foundation, the Hologram Core Technology Development Grant of the Ministry of Science and ICT, the Nano and Material Technology Development Project, and the Health and Medical R&D Project of the Ministry of Health and Welfare.
2024.07.30 View 1596 -
KAIST Develops Microbial Liquid Egg Substitute
A team of researchers published a paper on developing a substitute for eggs using microorganisms, grabbing international attention. It is expected that the development of egg substitutes using non-animal raw materials will solve the problems of factory farming, which causes problems like increased emission of greenhouse gas and waste, and contribute to building a sustainable food system that allows easy protein intake.
KAIST (President Kwang-Hyung Lee) announced that Research Professor Kyeong Rok Choi from the Biological Process Research Center and Distinguished Professor Sang Yup Lee from the Department of Chemical and Biomolecular Engineering have published a paper on the development of an "Eco-Friendly Liquid Egg Substitute Derived from Microorganisms."
Eggs play a crucial role in various culinary applications due to their unique physicochemical properties such as gelling, foaming, and emulsifying, while also providing essential nutrients. However, traditional egg production is not only unethical and resource-intensive but also has significant environmental impacts such as greenhouse gas emissions and waste issues. Additionally, factors such as wars and trade regulations have led to significant increases in egg prices, highlighting food security concerns. In response to these issues, there has been growing interest in egg substitutes made from non-animal sources to establish a sustainable food system.
Although there has been progress in developing non-animal protein-based egg substitutes, no substitute has been able to fully replicate the essential functional properties of liquid eggs, such as gelling and foaming, while also providing complete nutrition. In this context, the research team aimed to develop a liquid egg substitute using microbial biomass, which has a protein content comparable to that of meat per unit dry mass. Various microorganisms, such as yeast, Bacillus, lactic acid bacteria, and other probiotics, have been proven safe through long-term human consumption. Microbial biomass requires fewer resources like water and land during production, and possesses high-quality nutrients, making it a promising sustainable food resource.
< Figure 1. Comparison of heat treatment results of microbial pellets and microbial lysates >
However, the semi-solid microbial biomass recovered through microbial cultivation was observed to turn liquid upon heating, unlike liquid egg. To address this, the research team devised a microbial lysate by breaking down the cell walls and cell membranes of microorganisms, which correspond to the eggshell. They found that the microbial lysate's proteins coagulated when heated and formed a gel similar to that of liquid egg. The gel formed from the heated microbial lysate was found to have microscopic structures and physical properties similar to those of boiled eggs. The addition of microbial-derived edible enzymes or plant-based materials allowed for the adjustment of its properties, enabling the creation of various textures.
Furthermore, the researchers demonstrated that the microbial lysate could form stable foams widely used in baking, such as meringues (made from egg whites). They successfully baked meringue cookies using this lysate, showing its potential as a functional liquid egg substitute.
Distinguished Professor Sang Yup Lee stated, "This substitute has excellent nutritional components, making it suitable for regular food consumption. It is especially promising as emergency food for long-term space travel, wartime situations, and other emergencies. More importantly, it contributes to securing a sustainable food system."
< Figure 2. Example of foaming ability of microbial lysate and meringue cookie production >
< Figure 3. Example of foaming ability of microbial lysate and meringue cookie production >
The paper was published online in the journal npj Science of Food, issued by Nature.
- Paper Title: Microbial lysates repurposed as liquid egg substitutes
- Authors: Kyeong Rok Choi (first author), Da-Hee Ahn, Seok Yeong Jung, YuHyun Lee, and Sang Yup Lee (corresponding author)
This research was supported by the Ministry of Science and ICT's project for developing eco-friendly chemical technologies to replace petroleum (Project Leader: Distinguished Professor Sang Yup Lee, KAIST) and the Rural Development Administration's Agricultural Microorganisms Project Group (Director: Professor Pan-sik Jang, Seoul National University) for developing protein production technology from inorganic substances through microbial metabolic system control (Project Leader: Research Professor Kyeong Rok Choi, KAIST).
2024.07.05 View 3340 -
KAIST Employs Image-recognition AI to Determine Battery Composition and Conditions
An international collaborative research team has developed an image recognition technology that can accurately determine the elemental composition and the number of charge and discharge cycles of a battery by examining only its surface morphology using AI learning.
KAIST (President Kwang-Hyung Lee) announced on July 2nd that Professor Seungbum Hong from the Department of Materials Science and Engineering, in collaboration with the Electronics and Telecommunications Research Institute (ETRI) and Drexel University in the United States, has developed a method to predict the major elemental composition and charge-discharge state of NCM cathode materials with 99.6% accuracy using convolutional neural networks (CNN)*.
*Convolutional Neural Network (CNN): A type of multi-layer, feed-forward, artificial neural network used for analyzing visual images.
The research team noted that while scanning electron microscopy (SEM) is used in semiconductor manufacturing to inspect wafer defects, it is rarely used in battery inspections. SEM is used for batteries to analyze the size of particles only at research sites, and reliability is predicted from the broken particles and the shape of the breakage in the case of deteriorated battery materials.
The research team decided that it would be groundbreaking if an automated SEM can be used in the process of battery production, just like in the semiconductor manufacturing, to inspect the surface of the cathode material to determine whether it was synthesized according to the desired composition and that the lifespan would be reliable, thereby reducing the defect rate.
< Figure 1. Example images of true cases and their grad-CAM overlays from the best trained network. >
The researchers trained a CNN-based AI applicable to autonomous vehicles to learn the surface images of battery materials, enabling it to predict the major elemental composition and charge-discharge cycle states of the cathode materials. They found that while the method could accurately predict the composition of materials with additives, it had lower accuracy for predicting charge-discharge states. The team plans to further train the AI with various battery material morphologies produced through different processes and ultimately use it for inspecting the compositional uniformity and predicting the lifespan of next-generation batteries.
Professor Joshua C. Agar, one of the collaborating researchers of the project from the Department of Mechanical Engineering and Mechanics of Drexel University, said, "In the future, artificial intelligence is expected to be applied not only to battery materials but also to various dynamic processes in functional materials synthesis, clean energy generation in fusion, and understanding foundations of particles and the universe."
Professor Seungbum Hong from KAIST, who led the research, stated, "This research is significant as it is the first in the world to develop an AI-based methodology that can quickly and accurately predict the major elemental composition and the state of the battery from the structural data of micron-scale SEM images. The methodology developed in this study for identifying the composition and state of battery materials based on microscopic images is expected to play a crucial role in improving the performance and quality of battery materials in the future."
< Figure 2. Accuracies of CNN Model predictions on SEM images of NCM cathode materials with additives under various conditions. >
This research was conducted by KAIST’s Materials Science and Engineering Department graduates Dr. Jimin Oh and Dr. Jiwon Yeom, the co-first authors, in collaboration with Professor Josh Agar and Dr. Kwang Man Kim from ETRI. It was supported by the National Research Foundation of Korea, the KAIST Global Singularity project, and international collaboration with the US research team. The results were published in the international journal npj Computational Materials on May 4. (Paper Title: “Composition and state prediction of lithium-ion cathode via convolutional neural network trained on scanning electron microscopy images”)
2024.07.02 View 2607 -
KAIST appoints K-Pop Star “G-Dragon” Kwon Ji-yong as a visiting professor
KAIST (President Kwang Hyung Lee) announced on June 5th that its Department of Mechanical Engineering has appointed Kwon Ji-yong, a K-Pop star better known as G-Dragon, as a visiting professor. The appointment was officiated at the “Innovate Korea 2024” event held at the KAIST Sports Complex in the morning of the 5th.
This appointment was promoted to expand the global competitiveness of Korean culture by applying the latest scientific technology developed from KAIST to K-content and the cultural industry.
An official from Galaxy Corporation, Mr. Kwon’s agency, said, “Through this appointment, we expect to contribute to market innovation and to the global spread and growth of K-culture through research and development of ‘entertech’*.”
* Entertech: A compound word of ‘entertainment’ and ‘technology’ refering to an industry that creates new added value by combining ICT with intellectual property rights (IP) and contents, which are the core values of entertainment.
The newly appointed Visiting Professor Kwon Ji-yong is scheduled to give a special lecture on leadership to undergraduate and graduate students. The purpose is to share his experience and life as a world-class artist to provide KAIST students with vision and insight into the world, as well as the courage and inspiration to pioneer within their own fields of expertise.
In addition, cultural events are planned to be held to help facilitate communication with KAIST members and provide artistic experiences necessary to grow into creative and convergent talents.
Joint research that applies KAIST's various technologies to art and cultural contents will also be pursued. ‘(temporarily named) KAIST-Galaxy Corporation Entertech Research Center’ will be established within the Department of Mechanical Engineering, conducting ▴research on Digital Twin technology for Korean Wave artists, starting with G-Dragon himself ▴convergent research on science and technology encompassing artificial intelligence, robots, and metaverse and K-Culture and ▴research on the development of differentiated avatars of artists using the latest technologies such as volumetrics, motion capture, and haptics.
Galaxy Corporation produces highly talked about televised shows including 'Physical: 100 Season 2', which achieved the feat of ranking first in the Netflix’s ‘Global Top 10 Non-English TV Shows’ category, as well as 'Street Woman Fighter', '2 Days & 1 Night', 'Let's Play Soccer: Mungchyeoya Chanda' and 'Mr. Trot 2', and expanded its IP (intellectual property rights) to all aspects of entertainment, from broadcasting to the music industry by recruiting G-Dragon in December last year.
It is an 'entertech' company that is pioneering a new content market by combining IP with the latest digital technologies such as metaverse, avatar, and artificial intelligence (AI). Based on these achievements, it recently signed a partnership with a global investment bank (IB). Through global investment, the company is soon to be the first entertech startup to become a unicorn (corporate value of 1 trillion won).
Kwon Ji-yong said, “It is an honor to be a visiting professor at KAIST, where countless scientific geniuses come out of. I am hoping the best of science and technology experts and my expertise in the entertainment business will come together and a great synergy, a ‘big bang’ will be ensue as a result.
“More and more musicians are working with artificial intelligence and these cutting-edge technologies enable more diverse forms of creative work,” he continued. He also expressed his specific wish. “Through the AI avatar developed jointly by Galaxy Corporation and KAIST, I wish to communicate more closely with my fans around the world that I cannot meet so often otherwise.”
President Kwang-Hyung Lee said, “Considering that KAIST is a university that has always explored new things and pioneered unknown territories since its establishment, I believe that Kwon Ji-yong also shares KAIST's DNA in that he is a leader and pioneer who has attained world-class achievements in the world of culture and arts.”
President Lee continued expressing his expectations saying, “Kwon Ji-yong will not only contribute to taking KAIST’s science and technology to spread and grow K-culture on the global stage, through his activities but also in sharing his experience and spirit as the trend leader of the world, he will be an asset to the members of KAIST which aims to become a top-tier university.”
The period of Kwon Ji-yong’s professorship is two years from the 4th of this month to June of 2026. In addition, Professor Kwon Ji-yong has been appointed as KAIST’s global ambassador to help strengthen KAIST's international presence.
Professor Kwon Ji-yong, who began his career as G-Dragon, has established himself as an icon symbolizing Korean pop culture over 18 years as a member and the leader of the K-Pop idol group 'Big Bang', which debuted in 2006 and gained global popularity. While being recognized for his outstanding ability in all aspects of his music, from writing lyrics, composing, and producing to performing, he has also been active in fashion, becoming the first Asian man to be selected as a global ambassador for Chanel in 2016, spreading Korean music and fashion to the world.
In June, 2017, he released his 3rd solo album 'Kwon Ji Yong' on USB instead of the existing CD format, for the first time in Korea. He also attended CES, the world's largest home appliance and IT exhibition held in Las Vegas, USA in January of this year, extending his strides as a 'tech-tainer'.
2024.06.05 View 9073 -
A 20-year-old puzzle solved: KAIST research team reveals the 'three-dimensional vortex' of zero-dimensional ferroelectrics
Materials that can maintain a magnetized state by themselves without an external magnetic field (i.e., permanent magnets) are called ferromagnets. Ferroelectrics can be thought of as the electric counterpart to ferromagnets, as they maintain a polarized state without an external electric field. It is well-known that ferromagnets lose their magnetic properties when reduced to nano sizes below a certain threshold. What happens when ferroelectrics are similarly made extremely small in all directions (i.e., into a zero-dimensional structure such as nanoparticles) has been a topic of controversy for a long time.
< (From left) Professor Yongsoo Yang, the corresponding author, and Chaehwa Jeong, the first author studying in the integrated master’s and doctoral program, of the KAIST Department of Physics >
The research team led by Dr. Yongsoo Yang from the Department of Physics at KAIST has, for the first time, experimentally clarified the three-dimensional, vortex-shaped polarization distribution inside ferroelectric nanoparticles through international collaborative research with POSTECH, SNU, KBSI, LBNL and University of Arkansas.
About 20 years ago, Prof. Laurent Bellaiche (currently at University of Arkansas) and his colleagues theoretically predicted that a unique form of polarization distribution, arranged in a toroidal vortex shape, could occur inside ferroelectric nanodots. They also suggested that if this vortex distribution could be properly controlled, it could be applied to ultra-high-density memory devices with capacities over 10,000 times greater than existing ones. However, experimental clarification had not been achieved due to the difficulty of measuring the three-dimensional polarization distribution within ferroelectric nanostructures.
The research team at KAIST successfully solved this 20-year-old challenge by implementing a technique called atomic electron tomography. This technique works by acquiring atomic-resolution transmission electron microscope images of the nanomaterials from multiple tilt angles, and then reconstructing them back into three-dimensional structures using advanced reconstruction algorithms. Electron tomography can be understood as essentially the same method with the CT scans used in hospitals to view internal organs in three dimensions; the KAIST team adapted it uniquely for nanomaterials, utilizing an electron microscope at the single-atom level.
< Figure 1. Three-dimensional polarization distribution of BaTiO3 nanoparticles revealed by atomic electron tomography. >(Left) Schematic of the electron tomography technique, which involves acquiring transmission electron microscope images at multiple tilt angles and reconstructing them into 3D atomic structures.(Center) Experimentally determined three-dimensional polarization distribution inside a BaTiO3 nanoparticle via atomic electron tomography. A vortex-like structure is clearly visible near the bottom (blue dot).(Right) A two-dimensional cross-section of the polarization distribution, thinly sliced at the center of the vortex, with the color and arrows together indicating the direction of the polarization. A distinct vortex structure can be observed.
Using atomic electron tomography, the team completely measured the positions of cation atoms inside barium titanate (BaTiO3) nanoparticles, a well-known ferroelectric material, in three dimensions. From the precisely determined 3D atomic arrangements, they were able to further calculate the internal three-dimensional polarization distribution at the single-atom level. The analysis of the polarization distribution revealed, for the first time experimentally, that topological polarization orderings including vortices, anti-vortices, skyrmions, and a Bloch point occur inside the 0-dimensional ferroelectrics, as theoretically predicted 20 years ago. Furthermore, it was also found that the number of internal vortices can be controlled depending on their sizes.
Prof. Sergey Prosandeev and Prof. Bellaiche (who proposed with other co-workers the polar vortex ordering theoretically 20 years ago), joined this collaboration and further proved that the vortex distribution results obtained from experiments are consistent with theoretical calculations.
By controlling the number and orientation of these polarization distributions, it is expected that this can be utilized into next-generation high-density memory device that can store more than 10,000 times the amount of information in the same-sized device compared to existing ones.
Dr. Yang, who led the research, explained the significance of the results: “This result suggests that controlling the size and shape of ferroelectrics alone, without needing to tune the substrate or surrounding environmental effects such as epitaxial strain, can manipulate ferroelectric vortices or other topological orderings at the nano-scale. Further research could then be applied to the development of next-generation ultra-high-density memory.”
This research, with Chaehwa Jeong from the Department of Physics at KAIST as the first author, was published online in Nature Communications on May 8th (Title: Revealing the Three-Dimensional Arrangement of Polar Topology in Nanoparticles).
The study was mainly supported by the National Research Foundation of Korea (NRF) Grants funded by the Korean Government (MSIT).
2024.05.31 View 3641