Dielectrophoretic Microfluidic Chip Integrated With Liquid Metal Electrode for Red Blood Cell Stretching Manipulation

Cellular mechanical properties are closely related to cell physiological functions and status, and their analysis and measurement help understand cell mechanism. In this study, a microfluidic platform was built to measure the mechanical properties of cells by using dielectrophoretic (DEP) force. The electrodes generally used to stretch cells are made of indium tin oxide, Au, and Pt, which have inherent disadvantages. In this paper, galinstan alloy liquid metal was first introduced as microelectrode to form non-uniform electric filed for red blood cell stretching manipulation. The liquid metal microelectrode is easy to manufacture, low in price, stable at high voltage, and reusable. An effective microfluidic chip integrated with liquid metal electrode was designed and simulated, and a series of experiments to capture and stretch red blood cells was performed. The length of the red blood cells increased from 6 μm to 8 μm under the DEP force from 0 pN to 103 pN. This work also revealed the potential use of liquid metal as microelectrode to manipulate the microparticles and cells in a microfluidic chip.