Formation of organized molecular film and helical nanofibers of ferrocene derivatives having R‐12‐hydroxystearyl chains with asymmetric carbon was investigated. The 12‐hydroxystearyl chain, which induces “thixotropy” due to the formation and breakage of intermolecular hydrogen bonds, was introduced into the ferrocenyl unit. The structure of this derivative as a monolayer on the water surface and its Langmuir‐Blodgett (LB) film properties were analyzed. The monolayer showed a two‐dimensional phase transition, corresponding to the formation of fibrous morphology. In the LB multilayers, intermolecular hydrogen bonding between hydroxyl groups at the 12‐position of the chain and crystalline packing was observed. Raman mapping revealed the difference in surface morphology of each derivative depending on the number of 12‐hydroxystearyl chains. The derivative having the single chain showed a right‐handed helical morphology in the film and this behavior is similar to those having two and three chains. In circular dichroism spectra, the film showed a positive Cotton effect. Since the helical chains easily entangle with each other to form a sponge‐like organization, it was expected that the solvent uptake was the origin of gelation induction to its contact solvent.

sorption denaturation 11, 12. Among the monolayers formed at the air/water interface, the Langmuir monolayer 13 15 is a quasi-equilibrium state formed by external compression. On the other hand, the Gibbs monolayer 16 is formed in the equilibrium state between micelles and the interfacial adsorption film due to the presence of surfactant molecules in the aqueous solution Fig. 1. In general, the former is described by the surface pressure-area π-A isotherm 17 , and the latter by the surface pressure-time π-t isotherm 18. Langmuir films are water-insoluble monolayers 19 spread from an organic solvent. On the other hand, Gibbs monolayers are formed by water-soluble surfactant molecules 20. Biomolecules such as enzymes and proteins have abundant hydrophobic units, even though they are water-soluble in general, and their aqueous solution causes molecular adsorption at the air/water interface over time 21. During this time, it is thought that a conformational transition from a hydrophilic Abstract: Using glucose oxidase and salmon testis-derived DNA molecules, we sought to extend the recently proposed idea of interfacial adsorption denaturation. The surface pressure-time (π-t) isotherm of the glucose oxidase Gibbs monolayer exhibited a rapid increase in surface pressure and a relatively prompt transition to a liquid condensed film. The appearance of this rapid liquid expansion phase occurred much earlier than that previously identified for lysozyme, trypsin, cytochrome C, and luciferase. This experimental finding was linked to the number of hydrophobic residues in the constituent unit, and the number of hydrophobic residues in glucose oxidase was the highest among these biomolecules. On the other hand, DNA molecules do not have such hydrophobic groups, or present a positive surface on the π-t curve. However, interfacial adsorption occurred, and the existence of molecules at the air/water interface was confirmed, even in the two-dimensional gas phase state. Furthermore, it was confirmed that an increase in surface pressure was detected during the formation of a mixed film of DNA molecules and biomolecules, forming a stable Gibbs monolayer. This mimic the behavior of mixed monolayer formation with matrix molecules in Langmuir monolayers. Moreover, it was clarified that the interfacial adsorption denaturation behavior changed when pH dependence was evaluated considering the isoelectric point of the biomolecular group.

No abstract

The activity maintenance characteristics of proteases adsorbed and immobilized on a monolayer of organo-modified singlewalled carbon nanotubes (SWCNTs) were evaluated in this study. After forming a monolayer on the water surface of the organo-modified SWCNTs, protease was introduced into the subphase, and monolayer immobilization was attained by postadsorption. The protease-adsorbed organo-SWCNT multilayers were immersed in an aqueous solution of luminescent casein, and fluorescence emission was observed. Proteases had cleaved the molecular chain of luminescent casein, which causes luminescence. Although the protease in the aqueous solution could cleave the molecular chain only up to approximately room temperature, the protease immobilized on the solid substrate could cleave the chain up to 160°C, indicating sharp emission spectra.

IntroductionThe global pandemic during the last few years 1,2) has changed the lives of humankind; the threat of the virus to the human body 3,4) was highlighted again. However, owing to human wisdom, vaccines have been successfully developed to avoid the risk of aggravation due to infectious diseases 5,6) . Although protecting the innate health of the body through continuous vaccination at regular intervals is important, it is also important to prevent the entry of bacteria/viruses inside the body through everyday regular precautions, such as washing hands.At present, attention is on solvents and materials with antibacterial 7) , sterilizing 8) , and disinfecting properties 9) . Most of them are expected to be effective when applied with liquid substances. On the contrary, other materials are also present that utilize selective adsorption of fungi to surfaces 10) . Similar to fullerene 11,12) , carbon nanotubes 13,14) , and graphene 15,16) , nanodiamond 17−19) which is an allotrope of nanocarbon material, is claimed to have antibacterial properties 20) .The detonation method 18) , which uses explosives such as ＊ Correspondence to: Atsuhiro Fujimori,