Hydrodynamic vertical rotation method for a single cell in an open space

Rotation of a single cell is an indispensable cell manipulation technique for genetic studies and clinical applications. Conventional contact manipulation methods for rotation of a cell use complex control systems and tools, while conventional non-contact manipulation methods have limitations regarding the operating space or range of the rotated cell size. Here, we report on a convenient, non-contact, and open space method for a wide range of single cell sizes (micrometer scale to millimeter scale) rotating in a vertical plane (out-of-plane) of an open space. This method uses a vertical microscale recirculation zone for capturing and rotating the cell. We fabricated a micro-orifice on the surface of a microfluidic chip to generate the micro-recirculation zone and then carried out experiments on vertical rotations of Xenopus oocyte, embryoid body, brine shrimp oocyte, and zebrafish oocyte using this chip. We demonstrated the rotation of four types of cells in the vertical plane between the air–liquid interface and the top surface of the microfluidic chip; then, we conducted a simulation to analyze the dynamics of the vertical rotation of the Xenopus oocyte qualitatively. Our results indicated rotation speed of the four types of cells was controllable by the micro-recirculation zone. The size and density of oocytes also affected the process of capturing and rotation. We expect this method opens new research opportunities in three-dimensional cell manipulation, imaging, and analysis.