- World’s second successful demonstration of Scalable TF QKD network structure In modern cryptosystems, users generate public and private keys that guarantee security based on computational complexity and use them to encrypt and decrypt information. However, recently, modern public-key cryptosystems have faced potential security loopholes against quantum computers with great computational power. As a solution, quantum cryptosystems have been highly noticed. They use quantum keys that guarantee security based on quantum physics rather than computational complexity, thus they are secure even against quantum computers. Therefore, quantum cryptosystems are expected to replace modern cryptosystems. Quantum key distribution (QKD) is the most important technology for realizing quantum cryptosystems. Two main technical issues should be addressed to commercialize QKD. One is the communication distance, and the other is the expansion from one-to-one (1:1) communication to one-to-many (1:N) or many-to-many (N:N) network communication. Twin-field (TF) QKD, announced in 2018, is a long-distance protocol, which can dramatically increase the communication distance of QKD systems. In TF QKD, two users can distribute a key by transmitting quantum signals to an intermediate third-party that is for measurement. Given the inevitable channel loss, this architecture allows the users to increase the communication distance. However, despite its innovativeness, it has been experimentally demonstrated by only a few global QKD leading groups owing to the significant difficulty of system implementation, and research on the TF QKD network is still insufficient. The Korea Institute of Science and Technology (KIST, Director Seok-jin Yoon) announced that their research team, the Center for Quantum Information, led by director Sang-Wook Han, succeeded in an experimental demonstration of a practical TF QKD network. This is the second experimental demonstration of the TF QKD network in the world after the University of Toronto in Canada. The research team proposed a new TF QKD network structure scalable to a two-to-many (2:N) network based on polarization-, time-, and wavelength-division multiplexing. Unlike the first demonstration of the University of Toronto based on a ring network structure, the research team's architecture is based on a star network. The quantum signal in a ring structure must pass through every user connected to the ring, however, the star structure only has it go through the center, making it possible to implement a more practical QKD system. Besides, to overcome the main implementation obstacles to developing the TF QKD system, the team applied a plug-and-play (PnP) structure. A conventional TF QKD system requires many control systems, such as timing, wavelength, phase, and polarization controllers, to maintain the indistinguishability of two quantum signals emitted by two users’ different light sources. Whereas in the PnP TF QKD architecture developed by the KIST research team, the middle third-party generates and transmits the initial signals to both users using a single light source, and the signals return to the third-party by making a round trip. Therefore, the polarization drift due to the birefringence effect of the channel is automatically compensated, and users have fundamentally the same wavelength. In addition, due to the two signals passing through the same route in opposite directions, the arrival times of the signals are naturally identical. As a result, only a phase controller is required for implementing the research team's architecture. Based on the architecture, the team successfully conducted an experimental demonstration of a TF QKD network. "It is a significant research achievement showing the possibility of solving the two main obstacles to QKD commercialization, and we have gained a key technology leading the corresponding research," said Sang-Wook Han, the leader of the Center for Quantum Information. - Image 2:N TF QKD network structure

- Projected to create the next growth engine for the aerospace and defense industries, providing a gateway for Korea to become a materials superpower A space elevator, a technology connecting the Earth’s surface to a space station, would allow for the cost-efficient transport of people and materials. However, a very light yet strong material is essential to making such a technology a reality. The carbon nanotube is a new kind of material that is 100 times stronger, yet four times lighter, than steel, with copper-like high electrical conductivity and diamond-like thermal conductivity. However, previous carbon nanotube fibers were not ideal for extensive use, owing to the small contact area with adjacent carbon nanotubes and limited length they possessed. A research team led by Dr. Bon-Cheol Ku at the Korea Institute of Science and Technology (KIST; President: Seok-Jin Yoon) Jeonbuk Institute of Advanced Composite Materials in South Korea announced that it had developed an ultra-high-strength and ultra-high-modulus carbon nanotube fiber material through a joint research project with Professor Seongwoo Ryu’s research team at Suwon University (President: Chul-Su Park) in South Korea, and Dr. Juan José Vilatela from the IMDEA Materials Institute in Spain. Existing polyacrylonitrile (PAN)-based carbon fibers have high strength and a low modulus, whereas pitch-based carbon fibers have low strength and a high modulus. Previous studies on simultaneously improving the tensile strength and modulus of carbon fibers only focused on adding a small amount of carbon nanotubes. However, the KIST, Suwon University, and IMDEA joint research team produced fibers entirely consisting of carbon nanotubes without using the conventional carbon fiber precursors, polymer and pitch. The team manufactured high-density, high-alignment carbon nanotube fibers through a wet-spin manufacturing process suitable for mass production and then annealed them at high temperatures to enable their structures to be converted into various specific types, including graphite. Accordingly, the contact areas of the carbon nanotubes increased. These carbon nanotube fibers produced in such a way are expected to have various applications, as they simultaneously exhibit ultra-high strength (6.57GPa) and an ultra-high modulus (629GPa) characteristics, which could not be achieved with conventional carbon fibers. The fibers also showed high knot strength, indicating flexibility (Figure 2). Dr. Bon-Cheol Ku commented, “K-carbon fiber manufacturing technology using carbon nanotube materials is what will enable South Korea, a latecomer to the carbon fiber field, to lead the industry. This important technology will serve as the future growth engine for the aerospace and defense industries which is needed to propel South Korea into the realm of materials superpowers.” He continued, “We have secured the original technology for manufacturing carbon nanotube-based ultra-high strength and ultra-high modulus carbon fibers, but in order for the mass production of ultrahigh performance carbon fibers to be possible, the mass production of double-walled carbon nanotubes, a core material, must happen first,” stating that support on the national level as well as industry interest are needed to further progress. - Image Schematic of the structural changes of carbon nanotubes at different annealing temperatures

- Enhancement four times the conventional production rate, 100 times the durability compared to conventional commercial electrodes. - High potential use for LOHC hydrogen reservoir. "Carbon dioxide as a resource" and "hydrogen energy utilization" are considered to be the most practical measures to realize carbon neutrality. However, technological innovation is essential for them to be feasible both environmentally and economically. To this end, a Korean research team developed a proprietary technology that harnesses the synergy of both fields: "carbon dioxide as a resource" and "hydrogen energy utilization." The Korea Institute of Science and Technology (KIST; President: Seok-Jin Yoon) reported that the research group of Dr. Hyung-Suk Oh at the Clean Energy Research Center has developed a technology that stably converts carbon dioxide into useful liquid compounds (formate) by performing high-volume synthesis with fluorine-doped tin oxide catalysts. Also called methanoic acid, formate is a basic chemical raw material used in various industries such as food processing, preservatives, dyeing agents, plasticizers, snow removal agents, and cure retardants owing to its distinctive sour taste, anti-bacterial properties, and its ability to control pH. In recent years, it has also been in the spotlight as a raw material for eco-friendly biodegradable plastic. Because most formate is currently produced via the thermo-chemical reaction of fossil fuels, carbon dioxide emissions are inevitable during the manufacturing process. While it can be manufactured in an eco-friendly manner if carbon dioxide is directly converted into formate via an electro-chemical reaction, it would be necessary to increase electrode material performance responsible for converting the gas to a liquid phase, and to ensure durability, which allows electrodes to function stably for a long time. The KIST research team focused on the fact that fluorine-doped tin oxide has a lower tendency than regular tin oxide to metalize and maintain the carbon dioxide conversion activity of catalysts. By using a relatively simple method of doping fluorine during the synthesis of Tin oxide, the researchers developed an electrode that maintains high formate conversion activity in a stable manner. The fluorine-doped tin oxide electrode manufactured by the proposed method was shown to have a formate production rate that is four times that of an existing commercial tin oxide electrode, and its durability improved by at least 100 times, so its performance is maintained even during a long-term reaction time of over a week. Alternatively, formate is one of the most promising candidates as a liquid organic hydrogen carrier (LOHC), which is a hydrogen storage material that bonds hydrogen with a third substance to enable storage and transportation without the need to rely on expensive heavy-duty specialized containers. The core of LOHC technology is to secure liquefied compounds with high storage capacity for hydrogen and safety, even when exposed to external factors; formate has this characteristic. With the application of the technology developed by the researchers, as the environmental and economic concerns (which were previously considered weaknesses) will be resolved simultaneously, a reevaluation of its competitiveness is expected against other candidate materials such as ammonia. According to Dr. Hyung-Suk Oh, "By developing highly efficient electrodes, we can build a continuous system mass-producing formate from carbon dioxide." "Not only is this a direction for Carbon Capture, Utilization and Storage (CCUS), but also it is a "killing two birds in one stone" kind of technology that provides large amount of formate ideal for hydrogen storage. We expect it to contribute greatly to carbon neutrality in the future as the renewable energy supply increases and the hydrogen-based society advances, making the system economically feasible." - Image Production and utilization of formate with fluorine-doped tin oxide catalyst for CO2 conversion

- An artificial tactile neuron device that quickly and accurately converts the stiffness of a substance. - Combining with AI technology enables learning of the stiffness levels and distributions of the tumor, suggesting the possibility of cancer diagnosis. The stiffness levels and distributions of various biological materials reflect disease-related information, from cells to tissues. For example, malignant breast tumors are usually stiffer and have a more irregular shape than benign breast tumors. Ultrasound elastography can non-invasively determine the degree and shape of the tissue stiffness and is used for diagnosing breast cancer owing to its low cost. However, the opinion of an experienced expert is essential for interpreting ultrasound elastography images, but different experts differ in accuracy. The president of the Korea Institute of Science and Technology (KIST), Mr. Seok-Jin Yoon, announced that Dr. Hyunjung Yi's team at the spin convergence research center and Suyoun Lee, the director of the Center for Neuromorphic Engineering, had developed a simple but highly accurate disease diagnosis technology by combining tactile neuron devices with artificial neural network learning methods. Unlike the previously reported artificial tactile neuron devices, this tactile neuron device can determine the stiffness of objects. Neuromorphic technology is a research field that aims to emulate the human brain's information processing method, which is capable of high-level functions while consuming a small amount of energy using electronic circuits. Neuromorphic technology is gaining attention as a new data processing technology fit for AI, IoT, and autonomous driving, requiring the real-time processing of complex and vast information. Sensory neurons receive external stimuli through sensory receptors and convert them into electrical spike signals. Here, the generated spike pattern varies based on the external stimulus information. For example, higher stimulus intensity causes higher generated spike frequency. The research team developed an artificial tactile neuron device with a simple structure that combines a pressure sensor and an ovonic threshold switch device to produce such sensory neuron characteristics. Applying pressure to the pressure sensor causes the sensor's resistance to decrease and the connected ovonic switch element's spike frequency to change. The developed artificial tactile neuron device is a high-response, high-sensitivity device that allows the pressing force to generate faster electrical spikes while improving the pressure sensitivity, which focuses on the fact that stiffer materials result in faster pressure sensing when pressed. The electrical spike duration (or 1/frequency) generated by the developed device is less than 0.00001 s, which is more than 100,000 times faster than the several seconds it usually takes to press an object. Additionally, while the existing devices could detect a low pressure (approximately 20 kPa, similar to a force of light pressing) with a spike frequency change of 20 to 40 Hz, the developed device can detect the low pressure with spike frequency changes of 1.2 MHz. This allows real-time conversion of changes in the pressing force into spikes. To deploy the developed device to actual disease diagnosis, the research team used elastography images of malignant and benign breast tumors and utilized a spiking neural network learning method. Each pixel of the color-coded ultrasound elastography image which is correlated with the stiffness of the imaged material was converted into a spike frequency change value and used for training the AI. As a result, it was possible to determine the malignancy of a breast tumor with up to 95.8% accuracy. The KIST research team stated, "the developed artificial tactile neuron technology is capable of detecting and learning mechanical properties with a simple structure and method." The team added, "Through follow-up research, it will be possible to solve the noise reflection issue, which is a disadvantage of ultrasound elastography if artificial tactile neurons can collect an object's elastography image obtainable using ultrasound elastography." The team also expects the device to be helpful in low-power and high-accuracy disease diagnosis and applications such as robotic surgery where a surgical site needs to be quickly determined in an environment humans cannot directly contact." - Image The research results are published as an inside back cover paper in Advanced Materials.

- Discovery of dispersing solvent parameters affecting ionomer microporous structure - Performance improvement of proton-exchange membrane hydrogen fuel cells under high-temperature and non-humidified conditions A hydrogen fuel cell, which is a device that generates electrical energy through the reaction of hydrogen and oxygen in air, is gaining increasing attention as an eco-friendly power-generating device that do not emit pollutants. Among the various hydrogen fuel cells, proton-exchange membrane fuel cells (PEMFCs), which use ion-exchangeable polymer membranes as electrolytes, are relatively lightweight and have a faster start-up time. Owing to these characteristics, they are actively studied as a power source for homes and automobiles. Owing to their high electrochemical reaction rates and strong resistance to impurities at high operating temperatures, PEMFCs are ideal for applications in high-performance transportation, such as trucks, subways, trains, airplanes, and ships. However, a separate cooling system is required at high temperatures (>100 °C) to prevent ionic conductivity reduction triggered by evaporation in polymers. The weight added by cooling systems decreases the efficiency of PEMFCs. To use PEMFCs without a cooling system, high-temperature performance improvement and (80–200 ℃) non-humidification conditions are essential. The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) announced that Dr. Sung-Soo Lee’s team at the Material Structure Control Research Center, KIST, South Korea, and Dr. Yu-Seung Kim’s team at the Los Alamos Research Center (LANL), the U.S, have jointly developed a platform for controlling the microporous structure of ionomers, which is the key to improving the PEMFC performance. When polymer-containing phosphonic acid (RPO3H2) and polymer-containing sulfonic acid (RSO3H) combine, hydrogen from the sulfonic acid, which has a higher acid strength, is transferred to the phosphonic acid, thereby forming a protonated phosphonic acid ionomer. Using such a composite ionomer enables waterless ionic conduction, resulting in an increased performance of hydrogen fuel cells, even under high-temperature and non-humidified conditions. Further performance improvement can be expected through increased usage of reactive gases, such as hydrogen and oxygen. The KIST and LANL joint research team induced the accessibility of reactive gases by manipulating a composite ionomer to obtain a microporous structure. The team discovered the dependency of the composite ionomer’s microporous structure on the solvent in which it is dispersed, as well as a direct correlation between the dispersion solvent’s pKa (acid strength) and the phosphonic acid ionomer’s microporous structure. Subsequently, a performance evaluation of a high-temperature-hydrogen fuel cell confirmed that the composite ionomer’s microporous structure positively affected the performance of fuel cells. Dr. Sung-Soo Lee of KIST said, “The achievement is in discovering how important ionomer dispersion solvent pKa is in high-temperature-hydrogen fuel cells.” He revealed the significance of the study, adding, “We have expanded the use of hydrogen fuel cells from small transportation to bigger mobility such as trucks and ships.” This research was performed as part of the Advanced Research Projects Agency-Energy of the US Department of Energy, the Material Innovation Lead Project of the Ministry of Science and ICT (Minister Jong-Ho Lee), and the major projects of KIST. The research results are published in ‘ACS Energy Letters’ (IF:23.101, JCR top 3.302%). [Figure 1] The appearance of the protonated phosphonic acid film affected by the ionomer dispersion solvent, and the films’ microstructures and elemental analyses examined using electron microscopy. The red regions denote sulfonic acid (S) groups, and blue regions denote phosphonic acid (P) groups. The visible light transmittance (T%) and STEM-EDX [A2] at 550 nm, which are related to ionomer compatibility, are shown. A higher visible light transmittance results in increased film transparency. [Figure 2] MEAs’ power density treated with various dispersion solvents. MEA molded with a highly porous organic solvent displays a maximum power density.

- Development of polymer additives to solve the performance degradation of large-area solar cells based on the solution process. - Future expectations regarding solar cell technology commercialization that can be applied in printing technology Solar cell technology is a prominent clean energy source. In particular, organic solar cells, part of the third generation of solar cells, are gaining attention as a core technology for urban solar ray energy generation as they can be printed and applied to exterior walls or glass windows of buildings. However, the photoactive area that absorbs sunlight and converts it to electricity remains significantly smaller than 0.1 cm². Additionally, commercialization is obstructed by performance and reproducibility problems that occur when expanding the cell area to several m2 where practical energy supply levels are available. A research team led by Dr. Hae Jung Son of the Advanced Photovoltaics Research Center at the Korea Institute of Science and Technology (KIST; President: Seok-Jin Yoon) discovered the factors causing performance degradation in large-area organic solar cells and announced the development of a new polymer additive material for large-area, organic solar cell technology development. The research team focused on the photoactive layer’s compositional form in organic solar cells and the solution process, which is a part of the organic solar cell manufacturing process. The spin coating method, a solution process mainly used in the laboratory research stage, creates a uniform photoactive layer mixture as the solvent evaporates rapidly while the substrate rotates at a high speed. However, the large-area, continuous solution process designed for industrial use caused solar cell performance deterioration because the solar cell material solution’s solvent evaporation rate was too slow. Consequently, unwanted aggregation between the photoactive materials can be formed. The research team developed a polymer additive that can prevent this phenomenon by interacting with materials prone to aggregate. As a result, ternary photoactive layers containing polymer additives were fabricated to prevent aggregation in photoactive layers. Additionally, owing to possible nano-level structure control, solar cell performance improvements and stability security are acquired against light-induced temperature increases during solar cell operation. A 14.7% module efficiency was achieved, resulting in a 23.5% performance increase compared to that of the conventional binary system. Efficiency and stability were simultaneously demonstrated by maintaining over 84% initial efficiency for 1,000 hours, even in an 85℃ heated environment. KIST’s Dr. Son stated, “We have gotten closer to organic solar cell commercialization by proposing the core principle of a solar cell material capable of high-quality, large-area solution processing,” further expressing that “commercialization through follow-up research will make eco-friendly self-sufficient energy generation possible that is easily applicable to exterior building walls and automobiles and also utilized as an energy source for mobile and IoT devices.” - Image (left) high-efficiency, high-stability, organic solar module incorporating ternary photoactive layers. (right) Performance of the high-efficiency, high-stability, organic solar module incorporating ternary photoactive layers

- Small-molecule activation of innate immunity induces the infiltration of immune cells into cancer cells - Expected applications include various combination therapies for immuno-oncology Innovations in cancer immunotherapy have achieved clinical success by considerably increasing the survival rate of patients undergoing cancer treatment. However, there still exists an unmet medical need due to the low response rate to checkpoint inhibitors caused by the low immune reactivity of cancer cells in “cold” tumors. In their efforts to turn “cold” tumors into “hot” tumors, many global pharmaceutical companies have been focusing on utilizing the innate immune regulatory protein known as STING to increase the immunoreactivity of tumors and the infiltration of immune cells into the tumor microenvironment (TME). However, since clinical trials on the first STING agonist, ADU-S100, were suspended in 2020, there is an urgent need to develop new STING activators. Under these circumstances, a research team led by Dr. Sanghee Lee of the Brain Science Institute at the Korea Institute of Science and Technology (KIST; President: Seok-Jin Yoon), and Dr. Hyejin Kim of the Infectious Diseases Therapeutic Research Center at the Korea Research Institute of Chemical Technology (KRICT; President: Mihye Yi) announced the development of a new small-molecule STING agonist. Once the STING agonist was stimulated by a compound, it induced the secretion of cytokines such as interferons (IFNs) and activated an innate immune response mediated by T cells. The activated immune system altered the immune phenotype of the tumor, turning it from “cold” with a low reactivity to T cells to “hot” with a high reactivity, leading to the recruitment of T cells in the TME. In this study, compound administration effectively inhibited the growth of cancer cells in mice models. In particular, 20% of the treated group was found to be tumor-free as a result of the complete elimination of their tumors. Furthermore, immunological memory suppressed the growth of recurrent tumors without need for additional drug administration. Ultimately, no tumor growth was observed in the tumor-free group after the first treatment. Most of the existing STING agonists were subjected to intratumoral administration, which limited the broad application of cancer treatment, whereas the compound in this study was able to be administered by intravenous injection. In terms of further drug development, this agent is also able to be applied to combination cancer therapies and current standard treatments, such as radiation therapy, chemotherapy, and monotherapy. Dr. Lee stated, “Everyone dreams of vanquishing cancer; however, the development of cancer immunotherapeutics for ailments such as brain tumors is still limited. We hope that this study can provide the seeds for new therapeutic strategies for cancers where immunotherapy has had limited application.” Image Supplementary cover image of J. Med. A schematic diagram in which the substance developed in this study stimulates immune cells, activates an innate immune response, and induces cancer cell death. Chemical structure and mechanism of action of the STING agonist with the 4c compound developed in this study (left) and results and schematic diagram of anticancer efficacy in animal models (right).

- Dramatically improved the performance of 2D semiconductor devices by supressing the Fermi-level pinning phenomenon - Expected to speed up the commercialization of next-generation system technologies such as miniaturization of artificial intelligence systems To realize artificial intelligence systems and autonomous driving systems, which is often seen in movies, in everyday life, processors that function as the brain of computers must be able to process more data. However, silicon-based logic devices, which are essential components of computer processors, have limitations in that processing costs and power consumption increase as miniaturization and integration progress. To overcome these limitations, studies are being conducted on electronic and logic devices based on very thin two-dimensional semiconductors at an atomic layer level. However, it is more difficult to control the electrical properties through doping in two-dimensional semiconductors than in conventional silicon-based semiconductor devices. Thus, it has been technically difficult to implement various logic devices with two-dimensional semiconductors. The Korea Institute of Science and Technology (KIST; President: Seok-jin Yoon) announced that a joint research team led by Dr. Do Kyung Hwang of the Center for Opto-Electronic Materials and Devices and Professor Kimoon Lee of the Department of Physics at Kunsan National University (President: Jang-ho Lee), has succeeded in implementing two-dimensional semiconductor-based electronic and logic devices, whose electrical properties can be freely controlled by developing a new ultra-thin electrode material (Cl-SnSe2). The joint research team was able to selectively control the electrical properties of semiconductor electronic devices using Cl-doped tin diselenide (Cl-SnSe2), a two-dimensional electrode material. It was difficult to implement complementary logic circuits with conventional two-dimensional semiconductor devices because they only exhibit the characteristics of either N-type or P-type devices due to the Fermi-level pinning phenomenon. In contrast, if the electrode material developed by the joint research team is used, it is possible to freely control the characteristics of the N-type and P-type devices by minimizing defects with the semiconductor interface. In other words, a single device performs the functions of both N-type and P-type devices. Hence, there is no need to manufacture the N-type and P-type devices separately. By using this device, the joint research team successfully implemented a high-performance, low-power, complementary logic circuit that can perform different logic operations such as NOR and NAND. Dr. Hwang said that, “this development will contribute to accelerating the commercialization of next-generation system technologies such as artificial intelligence systems, which have been difficult to use in practical applications due to technical limitations caused by the miniaturization and high integration of conventional silicon semiconductor devices." He also anticipated that "the developed two-dimensional electrode material is very thin; hence, they exhibit high light transmittance and flexibility. Therefore, they can be used for next-generation flexible and transparent semiconductor devices." Image Operation results of the two-dimensional semiconductor device and logic device implemented by the joint research team Structure of the two-dimensional semiconductor electronic device implemented in this study (left) and its image captured through an electron microscope (right)

- New achievements of a durable cell mimic thin membrane structure - Tunable and controllable cell-like 3D shapes fabrication on a silicon substrate on-demand: New momentum for future biosensor In nature, the cell membrane has a unique function of protecting the internal from the external environment and communicating outside by sensing the external chemical or physical stimuli like the most precise biosensor for life. The cell membrane, which contains a hydrophilic part that is miscible well with water on the one side and a hydrophobic part that is not miscible well with water on the other, opens and closes ion channels like a water faucet and converts a physicochemical stimulus into an electrical signal which is then transmitted to cells. Active research worldwide on biosensors that can mimic the cell membrane’s excellent sensing has been suggested. However, till recently, the limited ability of an artificial cell membrane structure to only last a maximum of 5 days has been a hurdle. The Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) announced that the research team led by Dr. Tae Song Kim of the Brain Science Institute has succeeded in developing an artificial cell membrane that can be kept stable for over 50 days on a silicon substrate. This is the longest time reported in the field. In addition to creating, in 2018, an artificial cell membrane lasting for five days, in 2019, Dr. Kim’s team demonstrated the transfer of a positive ion to the inside of a structure with an artificial cell membrane with a protein attached to the surface, confirming its biosensor application potential. However, the durability of at least one month is essential for life science research utilizing artificial cell membranes and the practical commercialization of biosensors. To extend the limit of 5 days of stability of an artificial cell membrane, the KIST research team focused on a material called block copolymer (BCP). A BCP is a macromolecule consisting of two or more blocks, which can be repeatedly aligned as a long row of blocks of counteracting properties that mimic the hydrophilic and hydrophobic nature of the human cell membrane. Dr. Kim’s research team developed a technology that regularly arranges tens of thousands of holes with a diameter of 8 μm (micrometer) on a silicon substrate and inserts a specific amount of BCP solution into each hole through surface treatment, and dries it. Then, a soap bubble-shaped, an elongated oval-shaped, or a thin tubular-shaped BCP double-layer structure is tunably created by applying an electric field between the upper plate electrode of the microfluidic channel and the lower silicon substrate. This process led to the discovery of the possibility of maintaining a structure with a specific shape depending on the concentration of the solution and the applied electric field and frequency. This suggests a means to freely control the size and shape of artificial cell membranes, from a sphere, like a soap bubble, to a cylinder, like a tube. The KIST research team finally created an artificial cell membrane that can be kept stable for over 50 days by filling the outside of a three-dimensional double-layered BCP structure with a porous hydrogel that exhibits excellent elasticity and resilience characteristics similar to that of a human body substance. In addition, an artificial organ structure was produced by replicating an epithelial cell in the small intestine, which consists of thousands of tubular structures (cilia) using a BCP double-layered structure, proving its usage potential as a material for artificial organs through binding with β-galactosidase. Dr. Kim from KIST said, “While global research on artificial cell membranes has been focusing on placing a two-dimensional planar structure on a silicon substrate, the team has succeeded in extending the stability period of an artificial cell membrane by more than ten times following the development of the first three-dimensional artificial cell membrane structure fabrication technology,” and added, “The research, which has presented a path for large area array fabrication of artificial cell membranes, is expected to further develop into a platform technology for biological functionality research that identifies the roles of ultra-sensitive biosensors resembling cell functions, drug screening for new drug development, and neurotransmitters and hormones in the brain.” Image Schematic diagram of manufacturing double-layer structures of various sizes and shapes by controlling the concentration and electric-field of the block copolymer (PBd-PEO) by applying electric fields to the upper and lower layers of the substrate Numerous fabricated spherical and tubular structures and a lateral confocal photomicrograph of a single structure Size distribution of each spherical and tubular structure

- Excellent gold recovery performance even under the coexistence of metal ions and suspended solids - Significant reduction in cost and time of the recovery process, mass production of materials, and repeated recycling is possible In South Korea, which relies on imports for 99.3% of metal resources, the per capita consumption of metal resources is the highest in the OECD (Organization for Economic Co-operation and Development), and consumption of precious metals in various industries such as renewable energy, healthcare, and semiconductors is increasing. Among the different precious metals, gold is in demand in various fields such as batteries, electric vehicles, and renewable energy in the electric and electronic industries but always acts as a big variable in the industry due to its limited availability and high cost. Thus, research on ‘urban mining,’ which extracts precious metals from waste, is being actively conducted around the world. However, most of the technologies for extracting high-purity gold using waste resources require large amounts of chemicals and high operating temperatures; therefore, it has environmental regulations and efficiency problems. A Korean research team has developed a technology that can dramatically increase the recovery rate of precious metals from waste. The research team comprising Dr. Jae Woo Choi and Dr. Kyung-Won Jung from the Center for Water Cycle Research at the Korea Institute of Science and Technology (KIST, President Seok-Jin Yoon) reported that they developed a gold recovery process with the world’s highest recovery efficiency of 99.9 % by developing a capsule-type material in which a polymeric shell surrounds a multi-layered internal structure. The developed material has the advantage of high recovery efficiency compared to conventional adsorption materials since the material traps gold ions inside the capsule for recovery. The material also has the advantage of preventing the clogging of the internal porous structure since the polymeric shell allows gold ions to penetrate while being impermeable to suspended solids present with gold. By introducing functional groups that react only with gold ions in the multi-layered internal structure, gold that has passed through the polymeric shell could be stably recovered even with the coexistence of 14 types of ions and 3 types of suspended solids. Capsule-type material can be produced through a continuous process based on the solvent exchange method, and its efficiency and stability were demonstrated by maintaining a recovery performance of 99.9% or more even when the material was reused 10 times. Dr. Choi and Dr. Jung stated that, “The material developed through this research solves the problems of conventional materials developed for the recovery of precious metals. Moreover, it can be immediately applied to related industrial processes as they can be easily synthesized in large quantities". They also stated, “Through this study, it was evident that the chemical properties and morphology of the recovered material could also play a very important role in recovering metal resources from the water.” The lead author, Dr. Youngkyun Jung of KIST said that, “The results of this research are expected to serve as a basis for the development of the first eco-friendly process in Korea that can selectively recover and refine metal resources from waste and precious metal scraps generated in various industries, such as automobiles and petrochemicals.” Image Manufacturing process and the physical/chemical structures of gold recovery material Gold recovery concept of material (left) and its performance (right) (From left) gold-containing waste liquid, a capsule-type material wrapped in a circular polymeric shell (white) developed by KIST researchers to recover gold in an eco-friendly manner, gold extracted through the recovery process, and recovered gold refined into high-purity gold