Amphoteric β-1,3-glucans possessing both amino groups and carboxylic acid groups on the C6 positions of glucose units were designed and synthesized from naturally produced curdlan. The amphoteric polysaccharides showed the isoelectric point and the pH responsive interconversion between the original triple helix and single-stranded random structures. Since the pH dependences are comparable to the typical properties of proteins, the polysaccharides can be considered as a new class of giant amino acids. Utilizing the pH responsiveness, pH-controlled catch-and-release has been realized for cationic peptides or anionic DNA. We believe that the amphoteric polysaccharide can act as a new potential polymer to construct stimuli-responsive smart materials on the basis of the polysaccharide scaffold.

The amphoteric curdlan and a cationic polythiophene can form two distinct complexes as a function of medium pH. On the basis of such an environment-induced sequential interconversion of the amphoteric curdlan/polythiophene complex, we have successfully demonstrated the application of the complex as a naked-eye-detectable multicolor fluorogenic pH probe.The development of fluorogenic sensor molecules has attracted much attention because they can allow for highly sensitive detection of analytes by simple and practical procedures. To develop such fluorescent sensors, conjugated polymers are appreciated by many researchers in this field as potential candidates due to the unique physical properties of these polymers.1 Such polymers have an extended π-conjugated structure, resulting in the delocalization of electrons between the repeating monomer units. Such an electronic structure provides the polymers with semiconductivity, optoelectronic properties, light absorption, emission ability, etc. As observed in their doping effect leading to semiconductive polymers, the electronic structure of the conjugated polymers is extremely sensitive even to very small environmental perturbations. This is a remarkable advantage in constructing highly sensitive fluorogenic sensor molecules composed of conjugated polymers. In addition, the electronic structure of the conjugated polymer is sensitive to its conformational change. On the basis of such useful physical properties, the development of the conjugatedpolymer-based molecular sensors is making remarkable progress.2 Recently, water-soluble conjugated polymers have been applied to the fluorogenic sensor toward biological analytes, 3 nucleic acids, 4 proteins, 5 ions, 6 pH, 7 etc. because they possess one of the highest sensitivities as probes for biologically important circumstances.In the last decade, our research group became interested in the unique function and broad application of β-1,3-glucans. 8These polysaccharides form a triple-stranded helical structure; the helix can be reversibly converted between a single-stranded random coil and a triple helix by changes in solvent, pH, temperature, etc. Utilizing such a structural interconversion, we have already reported that the β-1,3-glucans, schizophyllan and curdlan, act as unique one-dimensional helical host molecules toward various guest molecules with different features, including nucleic acids, 9 conductive polymers, 10,11 dyes, 12 and nanoparticles. 13 In addition, we established a method to introduce stimuli-responsive motifs into the side chain of β-1,3-glucans.14 Most recently, we reported the development of amphoteric curdlans (ACs, Figure 1). 15 In that study, we found that (1) ACs showed an isoelectric point (pI) and the net charge is controllable by pH change, (2) owing to such a pH responsiveness, ACs displayed unique protein-like pH-responsive structural conversion, and (3) pH-responsive catch-and-release of the ionic drug model molecules, such as cationic peptide and anionic DNA, was successfully carried out ...

Purpose We recently reported that children and adolescents with a history of Kawasaki disease (KD) had slight but significant elastic arterial stiffness even when no coronary artery lesions (CALs) were present. Moreover, we hypothesized that KD-related arteriopathy may also cause peripheral artery dysfunction. The objective of this study was to assess the involvement of radial artery pulse waves, especially reflection waves from the peripheral arteries using the radial artery augmentation index (rAI) in patients without CALs after KD. Materials and methods We first collected the rAI data from 312 subjects (149 consecutive patients of KD and 163 control subjects). Next, 225 cases between 6 and 15 years old were selected. Finally, 41 pairs were included for analysis. The rAI values of these two groups were compared and analyzed. Acute-phase data were also collected to reveal the possible correlation with rAI in the convalescent period. Results Multivariable analysis revealed the history of KD was positively correlated with rAI@75 value in children from 6 to 15 years old. After pairing the height and gender, the KD group also had significantly higher rAI and rAI@75 than the control group (rAI 60.63±13.77 vs 54.56±13.17, p =0.028; rAI@75 63.61±15.21 vs 55.68±14.86, p =0.003). With regard to acute-phase condition, nonresponse to initial treatment was also linked to elevated rAI during the convalescent period. Conclusions During the convalescent period, the rAI increased in KD patients without acute CALs. Furthermore, nonresponse to initial treatment in acute phase conferred higher rAI to KD subjects than respondent cases. Elevated rAI means the reflection wave from the peripheral vascular is stronger or earlier. This small but significant change may indicate the existence of peripheral artery stiffness during the convalescent period.

The semi‐artificial branched‐polysaccharides, amylose‐grafted curdlans, were synthesized utilizing an enzymatic polymerization. Both a curdlan main chain and amylose side chains on the polysaccharides maintain the original helical structure as well as the molecular binding ability. Thanks to the difference in their molecular recognition properties between β‐1,3‐glucan chain and α‐1,4‐glucan chain, the amylose‐grafted curdlans can provide two different orthogonal binding sites within one polymeric system. When a water‐soluble polythiophene was mixed with the amylose‐grafted curdlan, the polythiophene was twisted in two different modes and therein, fluorescence energy of the polythiophene wrapped by the amylose side chains was successfully transferred to the polythiophene wrapped by the curdlan main chain. We thus concluded that in the dendritic superstructure of this polysaccharide, a self‐organized “Janus‐type FRET system” was successfully constructed.