High-resolution cell manipulation for longstanding load on red blood cells

A high-resolution cell manipulation system is presented for investigating red blood cell deformation under long-standing load in this paper. Because the low Reynolds number in microfluidic system, cell position can be manipulated by controlling the flow in a microchannel. A high-speed vision system is embedded in the system for providing cell present position as the feedback signal for the controller while a syringe pump actuated by a piezoelectric actuator is employed for flow control in the channel. The system is utilized for applying longstanding load on human red blood cells. The longstanding load is generated by manipulating a cell into a constriction channel where the cross-sectional size is smaller than the size of the cell. The cell has to deform due to the geometrical constraints of the constriction. Both the system performance and cell response to longstanding load have been evaluated. The manipulation system successfully achieves cell positioning as accurate as 0.24 μm while red blood cells are found always exponentially shrink with respect to time, and an average shrinkage of 1.82μm in 5 minutes is observed. Details of system construction and discussion on the cell response are presented.