Engineering
-
Professor Yim Decorated with the Chongjo Order of Merit
Professor Yong-Taek Yim from the Department of Mechanical Engineering was awarded the highest order of merit, the “Chongjo Keunjong Medal,” bestowed to public officials by the government in celebration of Invention Day on May 27.
Professor Yim was recognized for his innovative achievements to increase royalty income by introducing an IP-based management system at the Korean Institute of Machinery & Materials. He served as the president of KIMM for three years from 2014.
His idea led to new approaches to help explore diverse revenue creating sources such as dividend earnings and share sales, apart from simply relying on technology transfer fees. His efforts to disseminate the in-house R&D results also led to the foundation of six tech-based startups and spinoffs, which generated 11.2 billion KRW in sales. He also helped set up three spinoffs abroad.
Professor Yim said, “I pushed employee invention as a new value creator at KIMM. I thank each and every researcher and staff member at KIMM who worked so hard to create such an innovative IP-based R&D environment.”
2019.05.28 View 5785 -
5 Biomarkers for Overcoming Colorectal Cancer Drug Resistance Identified
< Professor Kwang-Hyun Cho's Team >
KAIST researchers have identified five biomarkers that will help them address resistance to cancer-targeting therapeutics. This new treatment strategy will bring us one step closer to precision medicine for patients who showed resistance.
Colorectal cancer is one of the most common types of cancer worldwide. The number of patients has surpassed 1 million, and its five-year survival rate significantly drops to about 20 percent when metastasized. In Korea, the surge of colorectal cancer has been the highest in the last 10 years due to increasing Westernized dietary patterns and obesity. It is expected that the number and mortality rates of colorectal cancer patients will increase sharply as the nation is rapidly facing an increase in its aging population.
Recently, anticancer agents targeting only specific molecules of colon cancer cells have been developed. Unlike conventional anticancer medications, these selectively treat only specific target factors, so they can significantly reduce some of the side-effects of anticancer therapy while enhancing drug efficacy.
Cetuximab is the most well-known FDA approved anticancer medication. It is a biomarker that predicts drug reactivity and utilizes the presence of the ‘KRAS’ gene mutation. Cetuximab is prescribed to patients who don’t carry the KRAS gene mutation.
However, even in patients without the KRAS gene mutation, the response rate of Cetuximab is only about fifty percent, and there is also resistance to drugs after targeted chemotherapy. Compared with conventional chemotherapy alone, the life expectancy only lasts five months on average.
In research featured in the FEBS Journal as the cover paper for the April 7 edition, the KAIST research team led by Professor Kwang-Hyun Cho at the Department of Bio and Brain Engineering presented five additional biomarkers that could increase Cetuximab responsiveness using systems biology approach that combines genomic data analysis, mathematical modeling, and cell experiments. The experimental inhibition of newly discovered biomarkers DUSP4, ETV5, GNB5, NT5E, and PHLDA1 in colorectal cancer cells has been shown to overcome Cetuximab resistance in KRAS-normal genes. The research team confirmed that when suppressing GNB5, one of the new biomarkers, it was shown to overcome resistance to Cetuximab regardless of having a mutation in the KRAS gene.
Professor Cho said, “There has not been an example of colorectal cancer treatment involving regulation of the GNB5 gene.” He continued, “Identifying the principle of drug resistance in cancer cells through systems biology and discovering new biomarkers that could be a new molecular target to overcome drug resistance suggest real potential to actualize precision medicine.”
This study was supported by the National Research Foundation of Korea (NRF) and funded by the Ministry of Science and ICT (2017R1A2A1A17069642 and 2015M3A9A7067220).
Image 1. The cover of FEBS Journal for April 2019
2019.05.27 View 57413 -
Professor Yim Appointed As Associate Editor of Nuclear Technology
Professor Man-Sung Yim from the Department of Nuclear and Quantum Engineering was appointed as the associate editor (for the Asian region) of Nuclear Technology ― a leading international research journal of the American Nuclear Society. Professor Yim will serve his term for three years from May 2019.
The American Nuclear Society, established in 1954, is comprised of more than 11,000 global members and aims to advance nuclear science, engineering, and technology while supporting the peaceful and beneficial applications of nuclear energy. Since its first publication in 1971, Nuclear Technology has been a representative journal of the society, reporting state-of-the-art information on all phases of the practical applications of nuclear technology.
Professor Yim is being recognized worldwide for his pioneering nuclear education, research, and policy studies in the fields of non-proliferation, safeguards for severe accident management, and waste management. He served as the head professor of the Department of Nuclear and Quantum Engineering and established the Nonproliferation Education and Research Center (NEREC) at KAIST.
Professor Yim remarked, “Asia has an important role to play at the forefront of the world’s nuclear research considering that nuclear development is most actively being carried out in the Asian region these days.”
2019.05.17 View 6215 -
Engineered Microbial Production of Grape Flavoring
(Image 1: Engineered bacteria that produce grape flavoring.)
Researchers report a microbial method for producing an artificial grape flavor. Methyl anthranilate (MANT) is a common grape flavoring and odorant compound currently produced through a petroleum-based process that uses large volumes of toxic acid catalysts.
Professor Sang-Yup Lee’s team at the Department of Chemical and Biomolecular Engineering demonstrated production of MANT, a naturally occurring compound, via engineered bacteria. The authors engineered strains of Escherichia coli and Corynebacetrium glutamicum to produce MANT through a plant-based engineered metabolic pathway.
The authors tuned the bacterial metabolic pathway by optimizing the levels of AAMT1, the key enzyme in the process. To maximize production of MANT, the authors tested six strategies, including increasing the supply of a precursor compound and enhancing the availability of a co-substrate. The most productive strategy proved to be a two-phase extractive culture, in which MANT was extracted into a solvent. This strategy produced MANT on the scale of 4.47 to 5.74 grams per liter, a significant amount, considering that engineered microbes produce most natural products at a scale of milligrams or micrograms per liter.
According to the authors, the results suggest that MANT and other related molecules produced through industrial processes can be produced at scale by engineered microbes in a manner that would allow them to be marketed as natural one, instead of artificial one.
This study, featured at the Proceeding of the National Academy of Sciences of the USA on May 13, was supported by the Technology Development Program to Solve Climate Changes on Systems Metabolic Engineering for Biorefineries from the Ministry of Science and ICT.
(Image 2. Overview of the strategies applied for the microbial production of grape flavoring.)
2019.05.15 View 52735 -
Professor Park at UPC-Barcelona Tech Receives Jeong Hun Cho Award
Professor Hyuk Park was honored to be the recipient of the Jeong Hun Cho Award which was presented at the Universitat Politècnica de Catalunya Barcelona Tech. The award recognizes young scientists in the field of aerospace engineering.
Professor Park, a graduate of KAIST’s Department of Mechanical Engineering in 2001, earned his MS and PhD at the Gwangju Institute of Science and Technology, and works at the Castelldefels School of Telecommunications and Aerospace Engineering at UPC-Barcelona Tech. He won this year’s award, which honors former PhD candidate Jeong Hun Cho at the Aerospace Engineering Department who died in a lab accident in 2003. Professor Park also received 25 million KRW prize money. Cho’s family endowed the award and scholarship in his memory. Since 2005, the scholarship has selected three young scholars every year who specialize in aerospace engineering from Cho’s alma maters of KAIST, Korea University, and Kongju National University High School.
Professor Park was selected as this year’s awardee in recognition of his studies of synthetic-aperture radar (SAR) satellite radiometer system, remote sensing radio frequency interference reduction system development, and 3CAT series research.
The Award Committee also chose three students for scholarships: PhD candidate Sang-Woo Chung from the Department of Aerospace Engineering at KAIST with 4 million KRW, PhD candidate Eun-Hee Kang from the School of Mechanical Engineering at Korea University with 4 million KRW, and Chan-Ho Song from Kongju National University High School with 3 million KRW.
2019.05.14 View 6129 -
Autophagy in Dendritic Cells Helps Anticancer Activity
Autophagy contributes to the homeostasis of a cell and recently another function of autophagy has been reported. A KAIST research team found that the autophagy of dendritic cells supports T-cell anticancer activity.
Autophagy is a process of maintaining cell homeostasis by removing cellular waste and damaged cellular organelles; nevertheless, its role in the presentation of phagocytized tumor-associated antigens remains vague.
Meanwhile, dendritic cells are the ones that recognize pathogens or cancer antigens, and induce immune responses in T cells. When cancer cells are killed by radiation or an anticancer drug, dendritic cells absorb and remove them and present antigens on their surface to transfer them to T-cells.
Professor Heung Kyu Lee from the Graduate School of Medical Science and Engineering and his team found that the autophagy of dendritic cells plays a key role in T-cell activation and they proposed the principles of enhancing anti-cancer effects.
Their experiments showed that T-cell activation of dendritic cells as well as anticancer immune response dropped when there is a deficiency of Atg5 (autophagy-related) in dendritic cells.
Interestingly, Atg5-deficient dendritic cells significantly elevated receptor CD36 on the surface of the cells, which increased the phagocytosis of apoptotic tumor cells yet restricted the activation of T-cells.
At this time, when introducing antibodies into the system in order to block the receptor CD36, the anti-tumor T-cell response increased substantially while tumor growth declined.
Professor Lee said, “This study allowed us to explore the role of autophagy in the anti-cancer immune response of T-cells. We look forward to developing targeted anti-cancer therapies using the receptor CD36.”
This research was published in Autophagy (10.1080/15548627.2019.1596493) on March 22, 2019.
Figure 1.Mechanism of autophagy in dendritic cells
Figure 2. A role of autophagy in dendritic cells
2019.05.13 View 49930 -
Education Innovation Day Reaffirms Rewarding of Excellence
Professors Tae-Eog Lee and Il-Chul Moon from the Department of Industrial & Systems Engineering received the Linkgenesis Best Teacher Award and the Soo-Young Lee Teaching Innovation Award on May 10. They were each awarded with 10 million KRW in prize money during the Education Innovation Day ceremony held at the Chung Kun-mo conference hall.
The award was endowed by KAIST Alumni Scholarship Chairman Hyung-Kyu Lim and KAIST Foundation Chairman Soo-Young Lee to support the innovation initiative and acknowledge faculty members who made significant contributions to educational innovation and benefited the general public though their innovations.
“KAIST’s vision for excellence and commitment to innovation is a game changer. Educational innovation is one of five pillars of Vision 2031, and it is our priority to foster critical and creative thinking students,” said President Sung-Chul Shin at the ceremony. All the awardees made presentation on their innovative projects and shared their ideas on better pedagogical methodology for next generation.
Professor Lee, dean of the KAIST Academy and the head of the Center for Excellence in Learning & Teaching was recognized for his contribution to enhancing educational quality through innovative learning and teaching methodology development. He has set up an Education 3.0 Initiative, an online education platform for flipped learning at KAIST.
Professor Moon also upgraded the online education platform to the 4.0 version and extended KAIST’s massive online courses through KOOC framework. This open platform offers more than 62 courses, with more than 170 thousand users registered since 2014.
Professor Song-Hong Park from the Department of Bio and Brain Engineering and Professor Jae-Woo Lee from the Department of Chemical and Biomolecular Engineering also won the Excellence Award.
2019.05.10 View 7101 -
KAIST Identifies the Cause of Sepsis-induced Lung Injury
(Professor Pilhan Kim from the Graduate School of Medical Science and Engineering)
A KAIST research team succeeded in visualizing pulmonary microcirculation and circulating cells in vivo with a custom-built 3D intravital lung microscopic imaging system. They found a type of leukocyte called neutrophils aggregate inside the capillaries during sepsis-induced acute lung injury (ALI), leading to disturbances and dead space in blood microcirculation.
According to the researchers, this phenomenon is responsible for tissue hypoxia causing lung damage in the sepsis model, and mitigating neutrophils improves microcirculation as well as hypoxia.
The lungs are responsible for exchanging oxygen with carbon dioxide gases during the breathing process, providing an essential function for sustaining life. This gas exchange occurs in the alveoli, each surrounded by many capillaries containing the circulating red blood cells.
Researchers have been making efforts to observe microcirculation in alveoli, but it has been technically challenging to capture high-resolution images of capillaries and red blood cells inside the lungs that are in constant breathing motion.
Professor Pilhan Kim from the Graduate School of Medical Science and Engineering and his team developed an ultra-fast laser scanning confocal microscope and an imaging chamber that could minimize the movement of a lung while preserving its respiratory state. They used this technology to successfully capture red blood cell circulation inside the capillaries of animal models with sepsis.
During the process, they found that hypoxia was induced by the increase of dead space inside the lungs of a sepsis model, a space where red blood cells do not circulate. This phenomenon is due to the neutrophils aggregating and trapping inside the capillaries and the arterioles. It was also shown that trapped neutrophils damage the lung tissue in the sepsis model by inhibiting microcirculation as well as releasing reactive oxygen species.
Further studies showed that the aggregated neutrophils inside pulmonary vessels exhibit a higher expression of the Mac-1 receptor (CD11b/CD18), which is a receptor involved in intercellular adhesion, compared to the neutrophils that normally circulate. Additionally, they confirmed that Mac-1 inhibitors can improve inhibited microcirculation, ameliorate hypoxia, while reducing pulmonary edema in the sepsis model.
Their high-resolution 3D intravital microscope technology allows the real-time imaging of living cells inside the lungs. This work is expected to be used in research on various lung diseases, including sepsis.
The research team’s pulmonary circulation imaging and precise analytical techniques will be used as the base technology for developing new diagnostic technologies, evaluating new therapeutic agents for various diseases related to microcirculation.
Professor Kim said, “In the ALI model, the inhibition of pulmonary microcirculation occurs due to neutrophils. By controlling this effect and improving microcirculation, it is possible to eliminate hypoxia and pulmonary edema – a new, effective strategy for treating patients with sepsis.”
Their 3D intravital microscope technology was commercialized through IVIM Technology, Inc., which is a faculty startup at KAIST. They released an all-in-one intravital microscope model called ‘IVM-CM’ and ‘IVM-C’. This next-generation imaging equipment for basic biomedical research on the complex pathophysiology of various human diseases will play a crucial role in the future global bio-health market.
This research, led by Dr. Inwon Park from the Department of Emergency Medicine at Seoul National University Bundang Hospital and formally the Graduate School of Medical Science and Engineering at KAIST, was published in the European Respiratory Journal (2019, 53:1800736) on March 28, 2019.
Figure 1. Custom-built high-speed real-time intravital microscope platform
Figure 2. Illustrative schematic and photo of a 3D intravital lung microscopic imaging system
Figure 3. Aggregation of neutrophils and consequent flow disturbance in pulmonary arteriole in sepsis-induced lung injury
2019.05.07 View 43455 -
Nanomaterials Mimicking Natural Enzymes with Superior Catalytic Activity and Selectivity for Detecting Acetylcholine
(Professor Jinwoo Lee from the Department of Chemical and Biomolecular Engineering)
A KAIST research team doped nitrogen and boron into graphene to selectively increase peroxidase-like activity and succeeded in synthesizing a peroxidase-mimicking nanozyme with a low cost and superior catalytic activity. These nanomaterials can be applied for early diagnosis of Alzheimer’s disease.
Enzymes are the main catalysts in our body and are widely used in bioassays. In particular, peroxidase, which oxidizes transparent colorimetric substrates to become a colored product in the presence of hydrogen peroxide, is the most common enzyme that is used in colorimetric bioassays.
However, natural enzymes consisting of proteins are unstable against temperature and pH, hard to synthesize, and costly. Nanozymes, on the other hand, do not consist of proteins, meaning the disadvantages of enzymes can be overcome with their robustness and high productivity. In contrast, most nanonzymes do not have selectivity; for example, peroxidase-mimicking nanozymes demonstrate oxidase-like activity that oxidizes colorimetric substrates in the absence of hydrogen peroxide, which keeps them away from precisely detecting the target materials, such as hydrogen peroxide.
Professor Jinwoo Lee from the Department of Chemical and Biomolecular Engineering and his team were able to synthesize a peroxidase-mimicking nanozyme with superior catalytic activity and selectivity toward hydrogen peroxide. Co-doping of nitrogen and boron into graphene, which has negligible peroxidase-like activity, selectively increased the peroxidase-like activity without oxidase-like activity to accurately mimic the nature peroxidase and has become a powerful candidate to replace the peroxidase.
The experimental results were also verified with computational chemistry. The nitrogen and boron co-doped graphene was also applied to the colorimetric detection of acetylcholine, which is an important neurotransmitter and successfully detected the acetylcholine even better than the nature peroxidase.
Professor Lee said, “We began to study nanozymes due to their potential for replacing existing enzymes. Through this study, we have secured core technologies to synthesize nanozymes that have high enzyme activity along with selectivity. We believe that they can be applied to effectively detect acetylcholine for quickly diagnosing Alzheimer’s disease.
This research, led by PhD Min Su Kim, was published in ACS Nano (10.1021/acsnano.8b09519) on March 25, 2019.
Figure 1. Comparison of the catalytic activities of various nanozymes and horseradish peroxidase (HRP) toward TMB and H₂O₂
Figure 2. Schematic illustration of NB-rGO Reactions in Bioassays
2019.04.30 View 36902 -
Research Day Highlights Most Outstanding Research Achievements
Professor Byung Jin Cho from the School of Electrical Engineering was selected as the Grand Research Prize Winner in recognition of his innovative research achievement in the fields of nano electric and flexible energy devices during the 2019 KAIST Research Day ceremony held on April 23 at the Chung Kunmo Conference Hall.
The ten most outstanding research achievements from the past year were also awarded in the three areas of Research, Innovation, Convergence Researches.
Professor Cho is an internationally recognized researcher in the field of future nano and energy device technology. Professor Cho’s team has continued to research on advanced CMOS (complementary metal-oxide semiconductors). CMOS has become his key research topic over the past three decades.
In 2014, he developed a glass fabric-based thermoelectric generator, which is extremely light and flexible and produces electricity from the heat of the human body. It is so flexible that the allowable bending radius of the generator is as low as 20 mm. There are no changes in performance even if the generator bends upward and downward for up to 120 cycles. His wearable thermoelectric generator was selected as one of the top ten most promising digital technologies by the Netexplo Forum in 2015.
He now is working on high-performance and ultra-flexible CMOS IC for biomedical applications, expanding his scope to thermal haptic technology in VR using graphene-CMOS hybrid integrated circuits; to self-powered wireless sensor nodes and self-powered ECG system using wearable thermoelectric generators .
In his special lecture at the ceremony, Professor Cho stressed the importance of collaboration in making scientific research and presented how he moved to future devices after focusing on scaling the devices.
“When I started the research on semiconductors, I focused on how to scale the device down as much as possible. For decades, we have conducted a number of procedures to produce tiny but efficient materials. Now we have shifted to develop flexible thermoelements and wearable devices,” said Professor Cho.
“We all thought the scaling down is the only way to create value-added technological breakthroughs. Now, the devices have been scaled down to 7nm and will go down to 5 nm soon. Over the past few years, I think we have gone through all the possible technological breakthroughs for reducing the size to 5nm. The semiconductor devices are made of more 1 billion transistors and go through 1,000 technological processes. So, there won’t be any possible way for a single genius to make a huge breakthrough. Without collaboration with others, it is nearly impossible to make any new technological breakthroughs.”
Professor Cho has published more than 240 papers in renowned academic journals and presented more than 300 papers at academic conferences. He has also registered approximately 50 patents in the field of semiconductor device technology.
The top ten research highlights of 2018 as follows:
- Rydberg-Atom Quantum Simulator Development by Professor Jaewook Ahn and Heung-Sun Sim from the Department of Physics
- From C-H to C-C Bonds at Room Temperature by Professor Mu-Hyun Baik from the Department of Chemistry
- The Role of Rodlike Counterions on the Interactions of DNAs by Professor Yong Woon Kim of the Graduate School of Nanoscience and Technology
- The Medal Preoptic Area Induces Hunting-Like Behaviors to Target Objects and Prey by Professor Daesoo Kim from the Department of Biological Sciences
- Identification of the Origin of Brain Tumors and New Therapeutic Strategy by Professor Jeong Ho Lee from the Graduate School of Medical Science and Engineering
- The Linear Frequency Conversion of Light at a Spatiotemporal Boundary by Professor Bumki Min from the Department of Mechanical Engineering
- An Industrial Grade Flexible Transparent Force Touch Sensor by Professor Jun-Bo Yoon from the School of Electrical Engineering
- The Detection and Clustering of Mixed-Type Defect Patterns in Wafer Bin Maps by Professor Heeyoung Kim from the Department of Industrial and Systems Engineering
- The Development of a Reconfigurable Spin-Based Logic Device by Professor Byong-Guk Park from the Department of Materials Science and Engineering
- The Development of a Miniaturized X-Ray Tube Based on Carbon Nanotube and Electronic Brachytherapy Device by Professor Sung Oh Cho from the Department of Nuclear and Quantum Engineering
Professor YongKeun Park from the Department of Physics and Professor In-Chel Park from the School of Electrical Engineering received the Research Award. For the Innovation Award, Professor Munchurl Kim from the School of Electrical Engineering was the recipient and the Convergence Research Awards was conferred to Professor Sung-Yool Choi from the School of Electrical Engineering, Professor Sung Gap Im from the Department of Chemical and Biomolecular Engineering, and Professor SangHee Park from the Department of Materials Science and Engineering during the ceremony.
For more on KAIST’s Top Research Achievements and Highlight of 2018, please refer to the attached below. click.
2019.04.25 View 13658 -
KAIST Unveils the Hidden Control Architecture of Brain Networks
(Professor Kwang-Hyun Cho and his team)
A KAIST research team identified the intrinsic control architecture of brain networks. The control properties will contribute to providing a fundamental basis for the exogenous control of brain networks and, therefore, has broad implications in cognitive and clinical neuroscience.
Although efficiency and robustness are often regarded as having a trade-off relationship, the human brain usually exhibits both attributes when it performs complex cognitive functions. Such optimality must be rooted in a specific coordinated control of interconnected brain regions, but the understanding of the intrinsic control architecture of brain networks is lacking.
Professor Kwang-Hyun Cho from the Department of Bio and Brain Engineering and his team investigated the intrinsic control architecture of brain networks. They employed an interdisciplinary approach that spans connectomics, neuroscience, control engineering, network science, and systems biology to examine the structural brain networks of various species and compared them with the control architecture of other biological networks, as well as man-made ones, such as social, infrastructural and technological networks.
In particular, the team reconstructed the structural brain networks of 100 healthy human adults by performing brain parcellation and tractography with structural and diffusion imaging data obtained from the Human Connectome Project database of the US National Institutes of Health.
The team developed a framework for analyzing the control architecture of brain networks based on the minimum dominating set (MDSet), which refers to a minimal subset of nodes (MD-nodes) that control the remaining nodes with a one-step direct interaction. MD-nodes play a crucial role in various complex networks including biomolecular networks, but they have not been investigated in brain networks.
By exploring and comparing the structural principles underlying the composition of MDSets of various complex networks, the team delineated their distinct control architectures. Interestingly, the team found that the proportion of MDSets in brain networks is remarkably small compared to those of other complex networks. This finding implies that brain networks may have been optimized for minimizing the cost required for controlling networks. Furthermore, the team found that the MDSets of brain networks are not solely determined by the degree of nodes, but rather strategically placed to form a particular control architecture.
Consequently, the team revealed the hidden control architecture of brain networks, namely, the distributed and overlapping control architecture that is distinct from other complex networks. The team found that such a particular control architecture brings about robustness against targeted attacks (i.e., preferential attacks on high-degree nodes) which might be a fundamental basis of robust brain functions against preferential damage of high-degree nodes (i.e., brain regions).
Moreover, the team found that the particular control architecture of brain networks also enables high efficiency in switching from one network state, defined by a set of node activities, to another – a capability that is crucial for traversing diverse cognitive states.
Professor Cho said, “This study is the first attempt to make a quantitative comparison between brain networks and other real-world complex networks. Understanding of intrinsic control architecture underlying brain networks may enable the development of optimal interventions for therapeutic purposes or cognitive enhancement.”
This research, led by Byeongwook Lee, Uiryong Kang and Hongjun Chang, was published in iScience (10.1016/j.isci.2019.02.017) on March 29, 2019.
Figure 1. Schematic of identification of control architecture of brain networks.
Figure 2. Identified control architectures of brain networks and other real-world complex networks.
2019.04.23 View 37462 -
On-chip Drug Screening for Identifying Antibiotic Interactions in Eight Hours
(from left: Seunggyu Kimand Professor Jessie Sungyun Jeon)
A KAIST research team developed a microfluidic-based drug screening chip that identifies synergistic interactions between two antibiotics in eight hours. This chip can be a cell-based drug screening platform for exploring critical pharmacological patterns of antibiotic interactions, along with potential applications in screening other cell-type agents and guidance for clinical therapies.
Antibiotic susceptibility testing, which determines types and doses of antibiotics that can effectively inhibit bacterial growth, has become more critical in recent years with the emergence of antibiotic-resistant pathogenic bacteria strains.
To overcome the antibiotic-resistant bacteria, combinatory therapy using two or more kinds of antibiotics has been gaining considerable attention. However, the major problem is that this therapy is not always effective; occasionally, unfavorable antibiotic pairs may worsen results, leading to suppressed antimicrobial effects. Therefore, combinatory testing is a crucial preliminary process to find suitable antibiotic pairs and their concentration range against unknown pathogens, but the conventional testing methods are inconvenient for concentration dilution and sample preparation, and they take more than 24 hours to produce the results.
To reduce time and enhance the efficiency of combinatory testing, Professor Jessie Sungyun Jeon from the Department of Mechanical Engineering, in collaboration with Professor Hyun Jung Chung from the Department of Biological Sciences, developed a high-throughput drug screening chip that generates 121 pairwise concentrations between two antibiotics.
The team utilized a microfluidic chip with a sample volume of a few tens of microliters. This chip enabled 121 pairwise concentrations of two antibiotics to be automatically formed in only 35 minutes.
They loaded a mixture of bacterial samples and agarose into the microchannel and injected reagents with or without antibiotics into the surrounding microchannel. The diffusion of antibiotic molecules from the channel with antibiotics to the one without antibiotics resulted in the formation of two orthogonal concentration gradients of the two antibiotics on the bacteria-trapping agarose gel.
The team observed the inhibition of bacterial growth by the antibiotic orthogonal gradients over six hours with a microscope, and confirmed different patterns of antibiotic pairs, classifying the interaction types into either synergy or antagonism.
Professor Jeon said, “The feasibility of microfluidic-based drug screening chips is promising, and we expect our microfluidic chip to be commercialized and utilized in near future.”
This study, led by Seunggyu Kim, was published in Lab on a Chip (10.1039/c8lc01406j) on March 21, 2019.
Figure 1. Back cover image for the “Lab on a Chip”.
Figure 2. Examples of testing results using the microfluidic chips developed in this research.
2019.04.18 View 29830