Hydrogel microrobots actuated by optically generated vapour bubbles

A novel hydrogel microrobot made of poly(ethylene glycol) diacrylate (PEGDA) is reported. This disk-shaped microrobot is optothermally actuated by laser-induced bubbles. A pulsed laser is used to smoothly actuate an 80-μm-diameter bubble microrobot at up to 320 μm s(-1). A single microrobot or a pair of microrobots working in cooperation were used to assemble 20-μm-diameter polystyrene beads into different patterns. The microrobots were also used to assemble patterns made of single yeast cells and cell-laden agarose microgels. The patterned yeast cells and cell-laden microgels were cultured, and the cells successfully multiplied.