A Modulated Helical Nanofilament Phase

Modifications to a Biphenolic Antibacterial Compound: Activity against ESKAPE Pathogens

Forty-four analogs of honokiol, a compound with known antibacterial activity, especially with respect to oral bacteria, were synthesized to explore the structure-activity relationships against the ESKAPE pathogens. Compounds with high therapeutic indices (hemolysis20 /MIC) were identified. In particular, ester-linked compounds that would be less than environmentally durable than biaryl ether antibacterials such as the broadly used triclosan were found to be active. MRSA mutants could be generated against some, but not all, of the highly active compounds. Based on gene sequencing results, membrane permeability, intracellular sodium, and intracellular pH assays revealed overlapping mechanisms of action.

Multidimensional Helical Nanostructures in Multiscale Nanochannels

We have investigated the various morphological changes of helical nanofilament (HNF; B4) phases in multiscale nanochannels made of porous anodic aluminum oxide (AAO) film. Single or multihelical structures could be manipulated depending on the AAO pore size and the higher-temperature phase of each molecule. Furthermore, the nanostructures of HNFs affected by the chemical affinity between the molecule and surface were drastically controlled in surface-modified nanochannels. These well-controlled hierarchical helical structures that have multidimensions can be a promising tool for the manipulation of chiral pores or the nonlinear optical applications.

Physico-chemical confinement of helical nanofilaments

Helical nanofilaments (HNFs) have attracted much interest because of their unique optical properties, but there have been many hurdles to overcome in using them for the practical applications due to their structural complexity. Here we demonstrate that the molecular configuration and layer conformation of a modulated HNF (HNFs(mod)) can be studied using a physicochemical confinement system. The layer directions affected by the chemical affinity between the mesogen and surface were drastically controlled in surface-modified nanochannels. Furthermore, an in situ experiment using grazing-incidence X-ray diffraction (GIXD) was carried out to investigate in detail the structural evolution through thermal transitions. The results demonstrate that the HNF(mod) structure can be perfectly controlled for functional HNF device applications, and a combined system with chemical and physical confinement effects will be helpful to better understand the fundamentals of soft matter.