Opto-thermal diffusiophoresis of soft biological matter: from physical principle to molecular manipulation

Transport of ions and molecules under external field gradients is fundamental phenomena relevant to many biological systems including molecular motors in nature. As inspired from such biological transport, novel optical manipulation by using local solute gradient and the creation of self-propulsive particles are being developed using this technology. In this review article, we describe the basic principles behind those transport phenomena under a temperature and a solute concentration gradient and discuss novel manipulation tools for soft biological materials. The control of such micron-scale transport will bring new insight in design principles of functional materials showing autonomous motion as seen in molecular motors.