Micro-particle transporting system using galvanotactically stimulated apo-symbiotic cells of Paramecium bursaria

Abstract

It is well known that Paramecium species including green paramecia (Paramecium bursa-ria) migrate towards the anode when exposed to an electric field in a medium. This type of a cellular movement is known as galvanotaxis. Our previous study revealed that an electric stimulus given to P. bursaria is converted to a galvanotactic cellular movement by involve-ment of T-type calcium channel on the plasma membrane [Aonuma et al. (2007), Z. Natur-forsch. 62 c, 93-102]. This phenomenon has attracted the attention of bioengineers in the fields of biorobotics or micro-robotics in order to develop electrically controllable micro-machineries. Here, we demonstrate the galvanotactic controls of the cellular migration of P. bursaria in capillary tubes (diameter, 1-2 mm; length, 30-240 mm). Since the Paramecium cells take up particles of various sizes, we attempted to use the electrically stimulated cells of P. bursaria as the vehicle for transportation of micro-particles in the capillary system. By using apo-symbiotic cells of P. bursaria obtained after forced removal of symbiotic algae, the uptake of the particles could be maximized and visualized. Then, electrically control-led transportations of particle-filled apo-symbiotic P. bursaria cells were manifested. The particles transported by electrically controlled cells (varying in size from nm to μm levels) included re-introduced green algae, fluorescence-labeled polystyrene beads, magnetic mi-crospheres, emerald green fluorescent protein (EmGFP)-labeled cells of E. coli, Indian ink, and crystals of zeolite (hydrated aluminosilicate minerals with a micro-porous structure) and some metal oxides. Since the above demonstrations were successful, we concluded that P. bursaria has a potential to be employed as one of the micro-biorobotic devices used in BioMEMS (biological micro-electro-mechanical systems). © 2009 Verlag der Zeitschrift für Naturforschung, Tübingen.