Collaborative micromanipulation using multiple bubble microrobots in an open reservoir

Abstract

Micromanipulation of bio-microobjects is useful in tissue engineering, and requires high-throughput, scalable, cell-friendly assembly of mesoscale structures with micron resolution. One potential method of achieving such functionality is manipulation by independently actuated multiple microrobots in cell-culture media. In this work, nine opto-thermocapillary flow-addressed bubble (OFB) microrobots were independently actuated in saline solution in an open reservoir. Laser heating generated the bubble microrobots in a fluid medium, and controlled the actuation of the microrobots. The microrobots were controlled using a computer-generated holographic (CGH) control system. The collaborative manipulation of four glass beads was demonstrated using two to three OFB microrobots. The microobjects were transported over several millimetres by moving the microscope stage for coarse motion, and by CGH control for fine actuation of the microrobots. Following transportation, the microobjects were assembled into a particular geometry. Independent actuation of multiple microrobots in saline solution along with collaborative long-range manipulation demonstrates the capability of the system to assemble cell-laden microgels over a large area with potential microscale accuracy, making this suitable for tissue engineering applications. This work also shows that the system is scalable, as tasks can be assigned to the required number of microrobots, and the system is compatible with a traditional open-reservoir cell-culturing environment.