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Scientists delve into the use of biopolymers as binders to prevent soil erosion in dikes and support plant growthSeveral eco-friendly biological soil treatment approaches have recently been proposed and verified in the laboratory as effective soil improvement methods. However, their validation in field-scale studies is lacking. To this end, scientists in Korea test a new method for soil reinforcement using biopolymer-based binders, bridging the gap between laboratory-scale experiments and actual implementations on the field and paving the way for erosion mitigation, revegetation, and river ecosystem preservation.Both natural and artificial dikes provide critical protection against floods. In a new study, scientists from Korea have tested an environment friendly soil treatment method that can help these structures withstand erosion. Photo courtesy: Smeerjewegproducties on ShutterstockAmong the various dreadful consequences of climate change, increased rainfall and flooding pose the greatest threat to people living near rivers. It is, therefore, important for civil engineers to mitigate the progressive deterioration of levees (dikes), both natural and artificial, due to soil erosion. While levee structures can be strengthened in many different ways, the most common practice involves using cement as a soil binder—an approach that causes high CO2 emissions and further accelerates climate change. Fortunately, a more environmentally conscious strategy has been the focus of soil research lately: biopolymer-based soil treatment (BPST). Biopolymers refer to molecules excreted by certain microorganisms that can be effectively used as eco-friendly binders for strengthening and stabilizing soil. However, while scientists regard BPST as a promising approach, its potential has been limited to laboratory experiments, with few field-scale tests conducted to determine the best practices for field implementations.Against this backdrop, a team of scientists led by Dr. Ilhan Chang of Ajou University, Korea, set out to bridge the gap between lab and field performances of BPST. Their study is now published online in Construction and Building Materials. “The strongest motivation for my research was to replace the high CO2-emitting cement with the low carbon-emitting microbial biopolymers in geotechnical engineering,” says Dr. Chang.The researchers developed and tested a new BPST on-site spraying method in which soil from the target site was mixed with biopolymers and applied on to a levee. They compared different biopolymer combinations and on-site mixing parameters and checked if adding the dry biopolymers to the mixing tank was better or worse than adding them as a pre-hydrated solution. They found that the solution form led to a better quality when mixed previously at a mixed volume of 1 m3 for 20 minutes or longer.Besides providing protection against erosion caused by wind and water, BPST naturally promotes the growth of vegetation and helps plants survive under harsh conditions. Thus, it can be leveraged to reduce the amount of chemical additives used in revegetation practices. Excited about its prospects, Dr. Chang says, “We believe that the BPST technology could become an effective countermeasure against global land degradation and desertification issues, as well as a powerful tool in afforestation projects.” Let us hope further research efforts will unlock the true potential of BPST, both as a protective strategy against the forces of nature and as a means to create a greener tomorrow.ReferenceAuthors:Seunghwan Seo1, Minhyeong Lee2, Jooyoung Im2, Yeong-Man Kwon2, Moon-Kyung Chung1, Gye-Chun Cho2, and Ilhan Chang3,*Title of original paper:Site application of biopolymer-based soil treatment (BPST) for slope surface protection: in-situ wet-spraying method and strengthening effect verificationJournal:Construction and Building MaterialsDOI:10.1016/j.conbuildmat.2021.124983Affiliations:1Department of Geotechnical Engineering Research, Korea Institute of Civil Engineering and Building Technology2Department of Civil and Environmental Engineering, Korea Advanced Institute of Science and Technology3Department of Civil Systems Engineering, Ajou University*Corresponding author’s email: ilhanchang@ajou.ac.kr About Ajou UniversityFounded in 1973, Ajou University has quickly grown to become one of the top universities in the Republic of Korea. With over 15,000 students and 50 research centers in diverse fields, Ajou University partakes in the largest national research and graduate education project funded by the Korean Ministry of Education. In line with its recently reformed vision, Ajou University’s goal is to change society by connecting minds and carrying out high-impact research to improve the welfare of people in and outside Korea. Website: https://www.ajou.ac.kr/en/index.do About the authorDr. Ilhan Chang is an Associate Professor with the Department of Civil Systems Engineering at Ajou University, Republic of Korea. He earned his B.S., M.S., and Ph.D. degrees in Civil and Geotechnical Engineering from Korea Advanced Institute of Science and Technology (KAIST). Dr. Chang and his research group are mainly focusing on multi-disciplinary research for emerging geotechnical engineering subjects, including soil characterization, ground improvement, soil erosion and preservation, biopolymer-based soil treatment (BPST), biological/bio-inspired soil treatment, anti-desertification, hydro-geotechnical engineering, new civil engineering materials, and sustainable urban development.
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43
- 작성자국제협력팀
- 작성일2021-10-27
- 7111
- 동영상동영상
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Researchers suggest a novel treatment protocol for tissue damage using stem cells within the patient’s bodyDespite remarkable progress in tissue engineering and stem cell therapeutics, stem cell injection is fraught with risks of cancer and is too expensive and time-consuming to be viable. Now, researchers suggest a novel treatment strategy using stem cells within the body to repair damaged tissues. They develop a novel system to promote the migration of the stem cells to the site of injury, facilitating tissue repair without the challenges of external stem cell manipulation. Stem cells have the ability to regenerate and heal damaged tissues. In a new study, researchers from Korea developed a strategy to treat tissue damage using stem cells within the body, which is safer compared to the conventional protocol. Courtesy: Shutterstock.With the development of sophisticated treatment strategies for tissue injury over the past decades, tissue engineering has made great strides towards effective tissue repair. Stem cell therapy is one such promising recourse to treat tissue damage. However, it is expensive, time-consuming, and has several undesirable side effects such as cancer progression. A better strategy is, therefore, needed to treat diseases caused by tissue degeneration.An alternative approach is to use the “endogenous stem cells” within our body to repair tissues. These cells reside in specific niches in the body and migrate to the site of injury to replace the damaged tissue. The transport or migration of these cells is regulated by “chemoattractants” (substances that attract motile cells of a particular type) such as the peptide Substance P (SP). However, SP does not activate the required number of endogenous stem cells to fully regenerate damaged tissues, thereby limiting our body’s self-healing capability.In a recent study published in the journal Small, researchers led by Prof. Moon Suk Kim and Prof. Sangdun Choi from Ajou University, Korea, found ways to improve and sustain the migration rate of endogenous stem cells using molecular dynamics simulations. They modified SP to develop a novel chemoattractant (SP1) and together with VEGF-mimicking peptide (VP), a biologically active factor to promote blood vessel formation, loaded it onto a liquid C/H hydrogel consisting of chitosan (Ch) and hyaluronic acid (HA). The hydrogel provided the role of a scaffold and a delivery system to direct both the chemoattractant and the VP to the site of tissue damage, while the blood vessel formation sustained the migration. This “SP1-loaded C/H-VP hydrogel” system can be injected at the site of treatment. Prof. Kim elaborates: “The newly discovered SP1 has approximately two to three times higher migration-inducing ability than that of the existing SP.”The researchers are hopeful their findings will offer a more promising solution to treat tissue degeneration in the future. “Our study indicates that SP1-loaded C/H-VP hydrogels offer a promising strategy to enable endogenous stem cell therapy, which is mostly free of side-effects and, thus, much safer,” comments Prof. Choi.His vision may not be too far from being realized! ReferenceAuthors: Seung Hun Park1, Hyeon Jin Ju1, Yun Bae Ji1, Masaud Shah1, Byoung Hyun Min1, Hak Soo Choi2, Sangdun Choi1* and Moon Suk Kim1,3*Title of original paper: Endogenous Stem Cell-Based In Situ Tissue Regeneration Using Electrostatically Interactive Hydrogel with a Newly Discovered Substance P Analog and VEGF-Mimicking PeptideJournal: Small DOI: https://doi.org/10.1002/smll.202103244 Affiliations: 1 Ajou University, Korea.2 Massachusetts General Hospital and Harvard Medical School, USA3 Medipolymers Research Institute, Korea*Corresponding author’s email: sangdunchoi@ajou.ac.kr, moonskim@ajou.ac.kr, About Ajou UniversityFounded in 1973, Ajou University has quickly grown to become one of the top universities in the Republic of Korea. With over 15,000 students and 50 research centers in diverse fields, Ajou University partakes in the largest national research and graduate education project funded by the Korean Ministry of Education. In line with its recently reformed vision, Ajou University’s goal is to change society by connecting minds and carrying out high-impact research to improve the welfare of people in and outside Korea. Website: https://www.ajou.ac.kr/en/index.do About Prof. Moon Suk KimDr. Moon Suk Kim is a Professor of Department of Molecular Science and Technology at Ajou University and the founder of Medipolymer Co., Ltd. He works on biomaterials-mediated drug and gene delivery, tissue and regenerative medicine, from design and synthesis of new drug carriers to mechanistic studies for the identification of critical delivery barriers and their potential therapeutic applications in several diseases. He also works on the application of nanostructured biomaterials for regenerative medicine, particularly focused on understanding the cell-topography interactions and their applications for stem cell engineering. He has published 230 peer-reviewed research manuscripts and holds more than 60 issued patents.About Prof. Sangdun ChoiProf. Sangdun Choi is a Professor of Department of Molecular Science and Technology at Ajou University and the founder of S&K Therapeutics Co., Ltd. He is an accomplished scientist in the Toll-like receptor (TLR) biology. He has dedicated his life to the discovery of underlying mechanisms and development of TLRs‐targeting therapeutics, which are involved in multiple diseases. He has published more than 200 papers in this area and currently holds several patents, with many more being filed. He has been awarded many prizes including the Korean Academy of Sciences Award for his contributions to the field of immunology.
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41
- 작성자국제협력팀
- 작성일2021-10-05
- 7345
- 동영상동영상
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Researchers overcome the fundamental optical limit of silicon-based semiconductors by changing their charge transport behavior with mechanical strainOptical applications of silicon-based semiconductors are limited to visible and near-infrared wavelengths owing to the fundamental energy band gap in silicon. Now, researchers from Korea have extended the optical limits of silicon crystals utilizing the “flexoelectric effect”, which reduces the band gap, opening doors to novel applications of silicon-based sensors in the wider infrared regime. Researchers applied a precisely controlled force using a pointed tip to induce strain gradient in a single silicon crystal, breaking its spatial inversion symmetry and extending the infrared response beyond its fundamental limit.Courtesy: Wiley Online LibraryModern electronics is ruled by silicon. Yet, its potential applications remain limited to the field of optoelectronics because of its fundamental energy gap, which confines its ability to absorb light within a certain wavelength range, limiting optical applications to visible and near-infrared-range devices only. But is there way around this fundamental limit? In a recent study published in Small Methods, researchers from Ajou University, Republic of Korea, led by Prof. Hyungtak Seo, took up the challenge to reengineer the fundamental energy gap of silicon and extend its usability for infrared applications. In accomplishing this feat, they took the hint from a physical phenomenon called “flexoelectric effect.” Silicon crystals possess an inherent inversion symmetry which, when broken by applying mechanical strain, gives rise to a spontaneous electric polarization. This, in turn, changes the “effective mass” of the free charge carriers in silicon, modifying its energy gap. When illuminated by light, the strained flexoelectric silicon undergoes a rearrangement in their electronic configuration that alters its fundamental absorption limit, a phenomenon known as the “flexo-photovoltaic effect.” The researchers took advantage of this response to demonstrate the photon sensing abilities of a single silicon crystal far beyond its fundamental energy gap. Prof. Seo explains, “We extended the sensitivity and responsivity of the silicon crystal to far-infrared wavelengths by introducing an inhomogeneous strain in the crystal using a pointed tip.” Additionally, they conducted photoconductive atomic force microscopic measurements to shed light on the flexoelectric photoresponse of the material and its tunability.The findings of this breakthrough study open up the possibility of using silicon-based materials for optical applications in the infrared (IR) region. IR photodetectors play a very important role in our day-to-day lives, from process control and exploration in industries to drug and explosive detection at security and defense facilities. Currently, these detectors use gallium/arsenic photosensors, which are expensive and difficult to work with. In contrast, silicon-based sensors are not only highly malleable but also economically viable. “Improving the IR photoresponse of silicon could help us build eco-friendly and cost-effective sensors not only for the industries but also healthcare, transport, and weather monitoring facilities,” comments an optimistic Prof. Seo.In nature, symmetry may not always be desirable. Sometimes, it needs to be broken!ReferenceAuthors:Mohit Kumar, Jaeseong Lim, Ji-Yong Park, and Hyungtak Seo*Title of original paper:Controllable, Self-Powered, and High-Performance Short- Wavelength Infrared Photodetector Driven by Coupled Flexoelectricity and Strain EffectJournal:Small MethodsDOI:10.1002/smtd.202100342 Affiliations:Department of Energy Systems ResearchAjou University, Republic of Korea*Corresponding author’s email: hseo@ajou.ac.kr About Ajou UniversityFounded in 1973, Ajou University has quickly grown to become one of the top universities in the Republic of Korea. With over 15,000 students and 50 research centers in diverse fields, Ajou University partakes in the largest national research and graduate education project funded by the Korean Ministry of Education. In line with its recently reformed vision, Ajou University’s goal is to change society by connecting minds and carrying out high-impact research to improve the welfare of people in and outside Korea. Website: https://www.ajou.ac.kr/en/index.doAbout Professor Hyungtak SeoProf. Hyungtak Seo received a Ph.D. in 2008 from North Carolina State University, USA, and worked at Lawrence Berkeley National Laboratory until September 2011. Since 2011, he has been a Professor at Ajou University, where he is the PI of the Advanced Electronic & Energy Materials (AEEM) Laboratory. His current interests are in (i) fabricating nano-materials for solar cells and photocatalysis applications; (ii) designing materials/devices for next-generation integrated circuit neuromorphic devices; (iii) tuning the electronic properties of nanoscale semiconductors for electrical and energy applications; (iv) and analyzing the properties of functional materials via UPS, XPS, ellipsometry, etc.
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39
- 작성자국제협력팀
- 작성일2021-08-26
- 8028
- 동영상동영상
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Professors Kim Wook and Yang Si-young’s team confirmed the osteoarthritis treatment mechanism of globular-shaped self-assembled hyaluronic acid nanoparticles. The recent finding is expected to contribute to improving in vivo safety and efficacy of linear hyaluronic acids used in chondroprotective agents for osteoarthritis. Professor Kim Wook (Department of Applied Chemistry & Biological Engineering, left in photo) and professor Yang Si-young (School of Medicine, right in photo) of Ajou University announced that the team has confirmed the chondroprotective efficacy of globular-shaped self-assembled hyaluronic acid nanoparticles and inflammation relief action. This means that target-specific drug carriers can become a potential therapeutic agent for osteoarthritis treatment.The study has been published in Biomaterials (IF 10.317), an international journal exploring the science of biomaterials and their translation towards clinical use, on June 19th with the title, “Self-Assembled Hyaluronic Acid Nanoparticles for Osteoarthritis Treatment.”The number of osteoarthritis patients continues to rise globally as lifespans have continued to lengthen, bringing to population aging. However, injection-type high-molecular-weight hyaluronic acids currently used in drugs and chondroprotective agents are not stable within a living body. The research team focused on self-assembled hyaluronic acid nanoparticles which are mainly used as in-vivo friendly, non-toxic, target-specific and long-acting drug carriers. As compressed globular-shaped self-assembled hyaluronic acid nanoparticles are relatively safer in vivo than linear hyaluronic acids, the team assumed that they are long-standing and provide increased inflammation relief. Accordingly, the team injected self-assembled hyaluronic acid nanoparticles into the knee joint of mouse models and observed through a multiphoton confocal microscope that the nanoparticles that penetrated the cartilage cell membrane conjugated with CD44 receptors and protected joint cartilage against osteoarthritis progression.This is evidence that multiple CD44-binding sites of nanoparticles conjugate with multiple CD44s at the same time, creating CD44 clustering in the cell membrane which effectively inhibits CD44 expression. The research team further explained that the drug carrier—self-assembled hyaluronic acid nanoparticles—itself, without any drug load inside, can inhibit CD44 receptors which aggravate joint cartilage erosion.In addition, the team reaffirmed that CD44 receptors can be a target for developing osteoarthritis treatments. CD44-deficient mouse models showed significantly lower osteoarthritis development compared to the control group with CD44 expression even when artificially inducing osteoarthritis in knee joints. The latest study suggests potential use of self-assembled hyaluronic acid nanoparticles as osteoarthritis treatments that interact with CD44. This recent finding is very meaningful as it provides a clue to overcoming the limitations of current linear hyaluronic acids and their low stability and inflammation-inducing effects due to product degradations.The study was sponsored by the Ministry of Science and ICT and the National Research Foundation of Korea as part of their Middle-grade Research Program and Bio/Medical Technology Development Program.<Self-Assembled Hyaluronic Acid Nanoparticles for Osteoarthritis Treatment Mechanism>
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- 작성자OIA
- 작성일2021-08-03
- 6857
- 동영상동영상
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A team of researchers led by Prof. Kim Sung-hwan, from the Departments of Physics and Energy Systems Research, has developed electronic skin capable of generating energy with a touch using silk protein nanofibers. This development is expected to be used as a next-generation bio-electronic material, generating electric energy or acting as sensory organs upon attachment to the human skin or soft robots. Prof. Kim announced successful development of electronic tattoos, which make it possible to draw circuits on silk protein nanofibers with carbon nanofiber ink using electrostatic-harvesting materials. Protein derived from silkworms is a skin-friendly, high-molecular biomaterial. The achievement was published online under the title, “Self-powered and Imperceptible Electronic Tattoos based on Silk Protein Nanofiber and Carbon Nanotubes for Human-machine Interfaces,” in Advanced Energy Materials (Impact Factor 25.245), a prestigious international journal covering energy materials, on May 11. Prof. Narendar Gogurla, Research Assistant Professor, participated as first author and worked together with Prof. Kim. There is a fast-growing body of research worldwide on materials for next-generation electronic healthcare devices for human-machine interfacing. Electrostatic-harvesting materials that leverage electrostaticity as an energy source are gaining more traction than ever. Electrostatic-harvesting materials can be used as a source of energy to move healthcare materials and artificial sensing organs that relay information related to human body movements. However, in order to increase energy efficiency, compatible materials should be used (e.g. hair and plastic show ideal electrostaticity), serving as an obstacle to generating electric energy in direct contact with human skin. In addition, the fact that the materials should be attached to human skin, no matter how uneven, while being composed of elements harmless to the human body, makes it harder to accelerate outcomes for research on electrostatic-harvesting materials. The team focused on silk proteins available from natural sources. Protein derived from silkworms is a skin-friendly, high-molecular biomaterial with superior physical and chemical properties. In the first step, the researchers make silk nanofiber paper, of a thickness equivalent to one-fiftieth of a strand of human hair, using electrospinning. Afterwards, they draw circuits on the silk nanofiber paper using carbon nanofiber ink and brush. Once the ink dries, the drawn circuits come out. Placing the circuits on slightly moist skin creates the electronic tattoo.The electronic tattoo is ultrathin, so it can be put on finely-wrinkled skin surfaces like finger pads while maintaining stability of its electric properties during everyday activities, besides taking showers. Electronic tattoos can easily be wiped off with wet wipes. Materials derived from silk nanofibers are harmless as the silk nanofibers are injected in the middle of the electronic tattoos.Interestingly, electronic tattoos attached to the human skin have the highest efficiency, signifying that other materials, including disposable gloves, should be worn to increase the efficiency of electrostatic energy. The harvested electric energy is sufficient to operate small electronic devices, such as LEDs and stopwatches. The fact that electric signals are generated with a single touch means that the tattoos can be used as artificial sensing organs. The team successfully drew pixel tattoos on the skin, proving that drawn circuits are capable of being converted into electric signals with the touch of a finger. Prof. Kim explained: “Although there has been significant progress in research on harvesting energy from the human body, the problems related to human-machine interfacing have been relatively neglected. Using proteins, of which natural skin is composed, interfaces capable of bridging the material difference between the human body and electronic devices can be developed.”He also added: “Our project is significant in that our invention can help increase the application of biomaterials to a variety of electronic devices. We hope to see our product applied to a wide range of healthcare products and soft robotics in the future.”The research was sponsored by the Rural Development Administration, the National Research Foundation of Korea, the BK21 FOUR, and the Gyeonggi-do Regional Research Center.Description: (Left) A conceptual diagram of a silk, electrostatic electronic tattoo, able to collect electric energy with a single touch on the skin using biocompatible electronic tattoos. (Right) An experiment on artificial sensing organs. Circuits drawn as pixel tattoos on the skin are capable of being converted into electric signals with the touch of a finger.
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- 작성자OIA
- 작성일2021-08-03
- 6084
- 동영상동영상
