Micropipette Aspiration

One of the oldest and most reported techniques is micropipette aspiration (or suctioning), which has been employed for characterizing nuclear mechanics in both isolated nuclei or intact cells. Here, mechanical properties are evaluated by applying a controlled negative pression (i.e., aspiration) to the nucleus and measuring its deformation. Dahl et al. (2005), performing micropipette aspiration on isolated nuclei of TC7 cells (African green monkey kidney epithelium), demonstrated the distinct roles of chromatin and Lamin B in the viscoelastic nuclear response. Successively, Pajerowski et al., applying this technique to the entire cell body, discovered a positive correlation between nuclear stiffness and progression of cell differentiation. Moreover, they assessed how chromatin and Lamin differently regulate nuclear rheology and deformability (Pajerowski et al., 2007). Neelam et al. employed micropipette aspiration (to the whole cell) to investigate the structural elements involved in the maintenance of nuclear shape and position in homeostasis. They observed that elastic forces developed in response to mechanical perturbation and necessary to restore initial nuclear position and shape are mainly linked to the action of intermediate filaments network composed by vimentin, Lamin A/C, and SUN-domain proteins (Neelam et al., 2015).