Cyclodextrin functions as a host molecule that can include external guest molecules in its hydrophobic cavity in water. In our laboratory, we have found that per-O-methylated β-cyclodextrin (TMe-β-CD) forms a stable 2:1 inclu­sion complex with 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS). The inclusion complex has a strong hydrophobic cavity around the porphyrin scaffold, similar to the environment of heme in heme proteins. We have synthesized a per-O-methylated β-CD dimer having pyridine linker (Py3CD) to make a biomimetic model compound of hemoglobin (Hb) and myoglobin (Mb). The inclusion complex of Py3CD with iron complex of TPPS (FeTPPS) is the first biomimetic Hb/Mb model complex in water. The complex, hemoCD, showed a very high CO binding affinity in vivo. When hemoCD was injected to animals (mice and rats) after exposure to CO, hemoCD captured CO during circulation and was excreted in urine without showing any toxic effect. These properties seem appropriate for the use of hemoCD as an inject­able antidote against CO poisoning. We have just started the drug development to implement hemoCD as a CO antidote for clinical use.

The growing demand for lithium-ion batteries requires improved performance and productivity. The formation of electronic conduction paths by carbon nanotubes (CNTs) is an important factor influencing electrode performance. However, only a few methods have been reported to allow direct and quantitative evaluation of CNT dispersion. Conventional ion milling for cross-sectional preparation exposes only CNTs in the interstices of active materials, limiting accurate assessment. In this study, we applied a fracturing method to prepare electrode cross sections, thereby exposing more CNTs in the observation area and enabling clear visualization of CNT networks. Furthermore, low-accelerating-voltage SEM enhanced the contrast between binders and CNTs, facilitating their separation and enabling quantitative evaluation of CNT linear density when combined with machine-learning-based image analysis. This study demonstrates a direct and quantitative method for assessing CNT distribution in lithium-ion battery electrodes.

Active matter often exhibits ordered collective motion, such as in bacterial colonies or swarms of fish and birds. Understanding the mechanisms underlying the complicated collective behaviors is significant to develop innovative chemical systems. We discovered that Pt catalytic particles with simpler structures exhibit a unique collective motion, that is, repetitive cluster formation and disintegration in an aqueous ethanol solution. In this study, the collective behavior of Pt particles is demonstrated in mixtures containing inert particles. Two distinct types of cluster formation were observed by varying the mixing ratio of the Pt and Au particles: Pt/Au mosaic-like clusters and Pt/Au core–shell clusters. In contrast, no Pt/silica cluster formation was observed in the silica particles mixed with Pt particles. In the Pt/Au core–shell clusters observed in this study, the thickness of the Au particle shell could be controlled by adjusting the concentration of the Au particle. This finding suggests that the spatial separation of Pt and Au particles can be realized under controlled conditions.

As grinding progresses, powders exhibit high surface activity due to the generation of ions and radicals, and interfacial effects become pronounced. Mechanochemical reactions that effectively utilize this surface activity have been applied to the synthesis of functionalized powders. In this study, a mechanochemical polymerization process was carried out continuously modifying the surface of silica particles by grinding silica sand in the presence of methyl methacrylate (MMA) using a dry bead mill. The effects of grinding conditions on the MMA conversion, particle size distribution, specific surface area, and chemical composition were investigated. As a result, the possibility of continuously producing surface-modified particles with polymer coatings accompanied by fine grinding was demonstrated. Furthermore, it was confirmed that optimizing the milling atmosphere and grinding conditions is crucial for improving the efficiency of polymer-modified powder production in this process.

3D printing has emerged as a promising technology for the production of personalized medicines, enabling freeform design and on-demand manufacturing. Selective laser sintering (SLS) is a solvent-free powder bed fusion technique capable of simultaneously fabricating dosage forms and inducing drug amorphization. However, the optimization of printing parameters and the reuse of powder materials remain key challenges for pharmaceutical applications. In this study, printlets containing either acetaminophen or indomethacin were fabricated using an SLS 3D printer with Kollidon^® VA64 as a thermoplastic polymeric excipient. The effects of SLS process parameters on printlet formability and drug dissolution were evaluated. The results demonstrated that printing temperature strongly influenced formability, with optimal values varying between formulations. Although the reuse of powder was not feasible due to physicochemical changes in the drug upon heat exposure, high manufacturing efficiency was achieved by maximizing the number of printlets produced per batch. Furthermore, indomethacin was successfully amorphized during the printing process, leading to a marked improvement in its dissolution behavior. These findings suggest that SLS 3D printing can serve as a one-step manufacturing platform for preparing amorphous solid dispersions and enabling flexible design of dosage forms for poorly water-soluble drugs.