We investigated the effects of the distance between redox site of multicopper oxidase from Pyrobaculum aerophilum (McoP) and the electrode surface on efficient electron transfer to optimize biodevice performance. The O₂ reduction peak current densities of the electrode on which McoP was directly immobilized using C-terminus His-tagged and Cys residue introduced McoP, and the electrode on which McoP was immobilized using C-terminus His-tagged McoP and self-assembled monolayer (SAM) were 203.6 µA/cm² and 167.4 µA/cm², respectively. The O₂ reduction current per unit enzyme activity of McoP was 88.9 mA/units in the electrode on which McoP was directly immobilized using C-terminus His-tagged and Cys residue introduced McoP, and 68.4 mA/units in the electrode on which McoP was immobilized using C-terminus Histagged McoP and SAM. McoP was directly immobilized onto Au electrode while controlling McoP orientation using cysteine residue on the C-terminus of McoP. As a result, O₂ reduction current was increased. Improving the electron transfer efficiency between redox site of McoP and electrode surface was achieved by reducing the distance between them.

Cerium oxide (CeO₂, ceria) particles were supported on cotton and nylon fabrics by immersing the fabrics into the solution containing cerium chloride (CeCl₃) with bubbling of ozone (O₃) gas. The amount of supported ceria on the fabrics was increased with increasing of [CeCl₃] concentration and immersing period. Ultraviolet-visual (UV-vis) spectra of the fabrics revealed that ultraviolet (UV) shielding properties were enhanced by the supporting of the particles and the properties were kept after washing with water and SDS solution. The exposure to UV light reduced stretching strength and breaking extension of the nylon fabric supported by titanium oxide (TiO₂, titania) particles, but they never reduced those of the fabrics supported by ceria particles.

We have developed a device for the simultaneous measurements of viscosity and light transmittance. In general, aqueous solutions of associative polymers often show gelation and/or phase separation. Viscometry and light transmittance have been standard methods in order to evaluate the gelation and phase separation,respectively. However, so far, a unified device to evaluate the both phenomena simultaneously has not been available, although such a device should bring numerous benefits to understanding the mechanism of the gelation and phase separation of aqueous associative polymers. In this study, constitution of the device and several examples of the device are presented.