Squeezing single cells to measure deformability

Understanding the mechanical behaviors of cells at the single cell level is crucial for studying biological functions from the bottom up. For example, variations in deformability, a basic mechanical characteristic of cells, may have ties to disease occurrence.

Microfluidic devices are important for their ability to measure such mechanical properties. Zhang et al. designed a pneumatic polydimethylsiloxane (PDMS) membrane within a tunable microfluidic chip to controllably squeeze single cells in the lateral direction.

“Our PDMS membrane, inspired by the Quake valve, allows lateral displacements under increasing air pressure, creating squeezing actions on cells,” said author Ziyu Han. “Since a series of deformations are all acted in the lateral direction, conventional microscopic imaging can be easily integrated into this system and subsequent image processing can be carried out for cell contour extraction and cell deformation studies.”

After imposing a series of deformations using the membrane, the researchers extracted and analyzed the contour changes of cells using computer vision. They compared two types of cells, which showed different performances under increased squeezing.

The team plans to examine more types of cells by combining the tunable microfluidic chip with conventional methods like atomic force microscopy. They also aim to integrate the pneumatic PDMS membrane structure with various single cell sensing strategies, such as fluorescence detection or electrical sensing.

“Cell mechanics is of vital importance in cell phenotyping, and new methods and strategies are needed to characterize cell mechanical behaviors,” said Han. “This is an interdisciplinary field that can bring together scientists from both biology and engineering to further develop our knowledge.”

Source: “Tunable microfluidic chip for single-cell deformation study,” by Ruiyun Zhang, Xuexin Duan, Shuaihua Zhang, Wenlan Guo, Chen Sun, and Ziyu Han, Nanotechnology and Precision Engineering (2023). The article can be accessed at https://doi.org/10.1063/10.0017649 .