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The flexibility of thermoelectric generators (TEGs) is important for low-contact thermal resistance to curved heat sources. However, approaches that depend on soft materials, which are used in most existing studies, have the problem of low performance in terms of the substrate’s thermal conductivity and the thermoelectric conversion efficiency of the thermoelectric (TE) elements. In this study, we propose a method to fabricate “Origami-TEG”, a TEG with an origami structure that enables both flexibility and the usage of high-performance rigid materials by self-folding. By applying the principle of the linkage mechanism to self-folding, we realized a fabrication process in which the TE element-mounting process and the active-material-addition process were separated in time. The fabricated origami-TEG showed similar internal resistance and maximum output power when attached to heat sources with flat and curved surfaces. Furthermore, it exhibited high-performance stability against both stretching and bending deformations.

A hollow microneedles array using biodegradable hyaluronic acid as the material for the microneedle array was fabricated. We proposed a method in which gelatinous hyaluronic acid was affixed to a core and then released after drying. A polylactic acid which has high tensile strength and high affinity for hyaluronic acid was used as the core material. Using this method, we succeeded at fabricating a highly safe hollow microneedle array. An opening was formed in the needle tip by coating the tip of the core with a hydrophobic UV curable resin. The diameter of the needle tip could be reduced by using a conical core, and the needle tip was sharpened by cutting it with a femtosecond laser. The mechanical strength of hyaluronic acid hollow microneedle was evaluated using the surface of artificial skin.