GAC
-
Analysis of Gas Adsorption Properties for Amorphous Porous Materials
Professor Jihan Kim from the Department of Chemical and Biomolecular Engineering at KAIST has developed a method to predict gas adsorption properties of amorphous porous materials.
Metal-organic frameworks (MOFs) have large surface area and high density of pores, making them appropriate for various energy and environmental-related applications. And although most MOFs are crystalline, these structures can deform during synthesis and/or industrial processes, leading to loss in long-range order. Unfortunately, without the structural information, existing computer simulation techniques cannot be used to model these materials.
In this research, Professor Kim’s research team demonstrated that one can replace the material properties of structurally deformed MOFs with those of crystalline MOFs to indirectly analyze/model the material properties of amorphous materials. First, the team conducted simulations on methane gas adsorption properties for over 12,000 crystalline MOFs to obtain a large training set data, and created a resulting structure-property map. Upon mapping the experimental data of amorphous MOFs onto the structure-property map, results showed that regardless of crystallinity, the gas adsorption properties of MOFs showed congruence and consistency amongst one another.
Based on these findings, selected crystalline MOFs with the most similar gas adsorption properties as the collapsed structure from the 12,000 candidates. Then, the team verified that the adsorption properties of these similar MOFs can be successfully transferred to the deformed MOFs across different temperatures and even to different gas molecules (e.g. hydrogen), demonstrating transferability of properties.
These findings allow material property prediction in porous materials such as MOFs without structural information, and the techniques here can be used to better predict and understand optimal materials for various applications including, carbon dioxide capture, gas storage and separations.
This research was conducted in collaboration with Professor Dae-Woon Lim at Kyoto University, Professor Myunghyun Paik at Seoul National University, Professor Minyoung Yoon at Gachon University, and Aadesh Harale at Saudi Arabian Oil Company. The research was published in the Proceedings of the National Academy of Sciences (PNAS) online on 10 July and the co-first authors were Ph. D. candidate WooSeok Jeong and Professor Dae-Woon Lim.
This research was funded by the Saudi Aramco-KAIST CO2 Management Center.
(Figure 1. Trends in structure - material property map and in collapsed structures)
(Figure 2. Transferability between the experimental results of collapsed MOFs and the simulation results of crystalline MOFs)
2017.07.26 View 8459 -
Nuclease-Resistant Hybrid Nanoflowers
An eco-friendly method to synthesize DNA-copper nanoflowers with high load efficiencies, low cytotoxicity, and strong resistance against nucleases has been developed by Professor Hyun Gyu Park in the Department of Chemical and Biomolecular Engineering and his collaborators.
The research team successfully formed a flower-shaped nanostructure in an eco-friendly condition by using interactions between copper ions and DNA containing amide and amine groups. The resulting nanoflowers exhibit high DNA loading capacities in addition to low cytotoxicity.
Flower-shaped nanocrystals called nanoflowers have gained attention for their distinct features of high surface roughness and high surface area to volume ratios. The nanoflowers have been used in many areas including catalysis, electronics, and analytical chemistry.
Of late, research breakthroughs were made in the generation of hybrid inorganic-organic nanoflowers containing various enzymes as organic components. The hybridization with inorganic materials greatly enhanced enzymatic activity, stability, and durability compared to the corresponding free enzymes.
Generally, the formation of protein nanocrystals requires high heat treatment so it has limitations for achieving the high loading capacities of intact DNA.
The research team addressed the issue, focusing on the fact that nucleic acids with well-defined structures and selective recognition properties also contain amide and amine groups in their nucleobases. They proved that flower-like structures could be formed by using nucleic acids as a synthetic template, which paved the way to synthesize the hybrid nanoflowers containing DNA as an organic component in an eco-friendly condition.
The team also confirmed that this synthetic method can be universally applied to any DNA sequences containing amide and amine groups. They said their approach is quite unique considering that the majority of previous works focused on the utilization of DNA as a linker to assemble the nanomaterials. They said the method has several advantageous features. First, the ‘green’ synthetic procedure doesn’t involve any toxic chemicals, and shows low cytotoxicity and strong resistance against nucleases. Second, the obtained nanoflowers exhibit exceptionally high DNA loading capacities.
Above all, such superior features of hybrid nanoflowers enabled the sensitive detection of various molecules including phenol, hydrogen peroxide, and glucose. DNA-copper nanoflowers showed even higher peroxidase activity than those of protein-copper nanoflowers, which may be due to the larger surface area of the flower- shaped structures, creating a greater chance for applying them in the field of sensing of detection of hydrogen peroxide.
The research team expects that their research will create diverse applications in many areas including biosensors and will be further applied into therapeutic applications.
Professor Park said, “The inorganic component in the hybrid nanoflowers not only exhibits low cytotoxicity, but also protects the encapsulated DNA from being cleaved by endonuclease enzymes. Using this feature, the nanostructure will be applied into developing gene therapeutic carriers.”
This research was co-led by Professor Moon Il Kim at Gachon University and KAIST graduate Ki Soo Park, currently a professor at Konkuk University, is the first author. The research was featured as the front cover article of the Journal of Materials Chemistry B on March 28, Issue 12, published by the Royal Society of Chemistry.
The research was funded by the Mid-Career Researcher Support Program of the National Research Foundation of Korea and the Global Frontier Project of the Ministry of Science, ICT & Future Planning.
(Figure: (A) Schematic illustration of the formation of nuclease-resistant DNA–inorganic nanoflowers. (B) SEM images showing time-dependent growth of DNA-nanoflowers. The concentration of A-rich ssDNA (Table S1, ESI†) was 0.25 mM.)
2017.04.14 View 8191 -
Distinguished Professor Sang-Yeop Lee gave keynote speech in '2011 China Bio-Refinery Summit'
Distinguished Professor Sang-Yeop Lee gave keynote speech in ‘2011 China Bio-Refinery Summit’ held in Chang’an, Beijing
Professor Lee gave a lecture on the vitalization strategy of ‘Bio-Refinery’, which is ‘A bio-based chemical industry to replace fossil fuel-based petro chemistry.
Professor Lee, insisted that for the successful construction of ‘Bio-Refinery’, there should be innovation in all value chain of biomass; biomass producer, bio-refinery business, consumer, government, etc. ▲Securement and distribution of Biomass ▲Development of strain and process for fermentation separation to effectively change biomass into chemical substance and fuel ▲Optimization of transportation and marketing.
During this summit, high-ranking government officials in politics and economics, executives of multicultural and Chinese business participated. From Korea, Do-Young Seung of Manager of technology research of GS and Hang-Deok Roh of laboratory chief of SK Chemical participated as panelist.
World Economy Forum, the gathering of leaders and experts in politics, economics, and policy created a ‘Global Agenda Council’ to find solutions on the issue of ‘sustainable growth of environment of the Earth and humanity’. Professor Lee is the chairperson of ‘Emerging Technologies Global Agenda Council (GAC)’ of Word Economy Forum.
Professor Lee, founder of ‘Systems Metabolic Engineering’, has made remarkable achievements world-wide, including a technology that manipulates metabolic circuit of microorganisms to purify various crude-originated chemical substances into environmentally friendly substances.
Currently, he is working on Systems biology research business in Ministry of Education, Science and Technology, Global Frontier Biomass business, Global Frontier Intelligent Bio-system construction and composition, to make progress in metabolic engineering which is essential for the bio-chemical industry.
2012.03.06 View 10695 -
Research Conducted on the Development Policy of Medical Researchers in United States
The topic dealt in the paper was “The Vietnam War and Medical Research: Untold Legacy of the U.S. Doctor Draft and the NIH ‘Yellow Berets’” and basically deals how a Doctor Draft made a positive impact on improving the basic research of clinical medicine.
Professor Park received his Doctorate at Johns Hopkins University and came to KAIST in 2007.
Summary of Dissertation
From the start of the Korean War in 1950 to the end of the Vietnam War in 1973 a large number of medical school graduates were drafted to the army. Of those drafted, 100 personnel were chosen annually to focus on researching in the National Institute of Health who developed into leaders of the field.
For example, those who worked as a researcher at the National Institute instead of their armed services were 1.5 times more likely to become a tenured professor, 2 times more likely to be promoted to Dean of the department, and 3 times more likely to be the Dean. In addition, 9 out of 50 Nobel Prize winners in fields of natural sciences between 1985 and 2007 were from the same pool of researchers, and 10 out of 76 recipients of National Medal of Science were also from the same pool of researchers.
They were named the ‘Yellow Berets’ like the special forces ‘Green Berets’ and made great contribution to the field in implementing and executing the bench to beside culture that involves development in laboratories to clinical testing.
Professor Park maintains that there has to be improvements made in current policies to encourage research work in medical graduate schools.
2011.05.31 View 10306