Abstract
Background Cell mechanics focuses on the mechanical properties of the cells and how they affect biological behaviors of cells. Mechanical property change of cells can reflect specific diseases and conditions. Therefore, detecting the changes in cell mechanical properties can potentially be associated with diagnosis and treatment of diseases.MethodsMechanical properties of living and dead human corneal epithelial cells (HCECs) were investigated with nano-indentation method using atomic force microscopy (AFM). Sneddon model was adopted to analyze the contacts between pyramidal AFM tip and soft materials. Polyacrylamide (PAAm) substrates with different stiffness were fabricated and human corneal epithelial cells (HCECs) were cultured on them. By applying nano-indentation to HCECs, we examined the distribution of elasticity across cells, and studied the differences between living and dead cells. Findings The central part of a cell, closer to nucleus, was more compliant than the outer regions, toward the surface of the cell’s lipid bilayer. Also, HCECs became stiffer as the stiffness of the substrate increased. Moreover, it was found that dead cells have much higher elastic moduli and exhibited elastic behavior, while living cells showed highly viscoelastic behavior.InterpretationAFM probing is an effective tool for characterizing cell mechanical behavior. More indentation results should be made in further studies to form statistical model of elasticity distribution for HCECs. This study can be extended to investigate the mechanical behaviors of benign and malignant cells or drug interactions on cells, which can establish more probable mechanical property–disease connections.
Mechanical property measurements of growing lysozyme crystal by atomic force microscopy with laser confocal differential interference microscopy
