A landing shock absorbing device 18 disposed in a foot mechanism 6 of a leg of a robot, wherein an inflatable bag-like member 19 is provided at a bottom face side of the foot mechanism 6. The movable member includes a movable member body disposed substantially horizontally and formed with the insertion holes into which contact pins are inserted, respectively, and a projection piece projecting upward from the movable member body. Suitable additives for use as solution stability additives in accordance with the present invention are selected from the group consisting of acetic acid, glycolic acid, and mixtures thereof. The shape and the location of the magnet unit in the reactor unit are adjusted in a preferable manner to collect the desired biological component.