Innovation of separation techniques
Study of weak intermolecular interactions on solid-liquid interphase and their applications to separation chemistry
On the one hand, HPLC has been used for various fields, mainly for pharmaceutical analysis, and remarkably developed as a core technique of separation analysis. On the other hand, substances that can be hardly separated with a separation mode still exist, and as a better driving force in separation, effectiveness of various π interactions caused from aromatic ring has been expected. But weak π interaction makes verification in experiment harder, and theoretical explanation assuming through computational science and spectroscopic methods have been addressed.
We try to quantitatively understand weak π interactions and achieve effective separations for solutes that are difficult to be separated by optimizing the design of stationary phases in a column and composition of a mobile phase for HPLC. To obtain effective π interaction in liquid phase separation, we focused on fullerene, the smallest size in nano carbon materials, fabricating an HPLC column immobilized C60- and C70- fullerenes. As a result, we found very unique molecular recognition occurred from π-π interaction and spherical recognition as well as CH (or OH) – π interaction in non-polarized solvents. Moreover, we achieved separation of H/D isotope mixtures and precise separation of an unlabeled sugar chain, experimentally showing halogen-π bonding between the C70 column and halogen atoms. These achievements are not only the first experiment revealing π interaction in the experiment but also the extremely important result for a basic knowledge of interaction between molecules.
Development of molecular recognition materials for selective separation, purification, and detection
To realize quantitative analysis with high accuracy for objective compounds in environmental and biological analytes from large amounts of contaminants, selective separation and concentration techniques are demanded.
We focus on specific molecular recognition of an organic polymer. Thus, we originally developed various methodologies of synthesizing separation media for low molecular to macromolecule by arranging molecularly imprinting technique. We also created the highly selective screening method for toxic chemical substances using separation media mimicking some molecular recognition of a receptor.
Besides, in recent study, we reported selective adsorption of (glyco) proteins and their simple detection using hydrogels. This detecting technology has contributed to application of simple onsite analysis.
Development of liquid phase separation for rapid and highly selective separation of biological substances
Miniaturization of substrates and further functionalization to improve separation ability are necessary to develop separation agents for liquid phase separation such as HPLC. Meanwhile, shorter operation time and lower costs are critical in the pharmaceutical, the environmental, and the synthetic chemistry field because of recent increase in number of analytes to be analyzed.
Then we focus on the inexpensive materials produced in factories, starting to develop porous macromolecules (spongy monolith) as a novel separation medium to realize high performance, high selectivity, low cost, and eco-friendly. To improve the performance especially for chromatographic method, we solved several problems such as complicating preparation of the purification process for biopharmaceutical as well as the low recovery rate, low reproducibility, and costly of separation analysis. Ultimately, we achieved a simple and rapid separation, which solved these problems.
In present, the multifunctioning detecting device for specific antibodies of an autoimmune disease and selective separation and concentration of nanoparticles based on chemical surface properties of the particles such as vesicles (exosome) and virus (SARS-CoV-2) have been worked on. What is more, we are starting a business venture from Kyoto university to develop our product as a super high-performance purification device of biopharmaceutical.
