Nanopillars probe cell nuclei

Researchers in California in the US say they have used vertical nanopillars made from quartz to probe the cell nucleus and look at how it deforms under applied mechanical strain. Such experiments are important for better understanding this organelle and the role it plays in disease.

 

Nuclear envelope deforms around nanopillars

The nucleus is the largest organelle in the cell and is responsible for its mechanical strength. When the nucleus is damaged and deforms, diseases like dilated cardiomyopathy, muscular dystrophy and Hutchinson-Gilford progeria can set in.
Probing the mechanical properties of the cell nucleus is no easy task, however, and the most common techniques to do this (micropipette aspiration, atomic force microscopy and parallel plate compression) are very invasive and time consuming.

Nanopillars push and deform cell nucleus

Now, a team of researchers led by Bianxiao Cui and Yi Cui of Stanford University are saying that vertical nanopillars can be used to push and deform the cell nucleus thanks to the cell’s own adhesion forces, and that the deformation which occurs can be quantified to measure the mechanical strength of the nucleus quickly and non-invasively.
The nanopillars can deform the nucleus over distances of just nanometres as opposed to microns in previous such techniques. Micron-scale deformation is mostly only seen in cancerous cells in which cell nuclei become very deformed. The nuclei from patients with Hutchinson-Gilford progeria or lamin A deficiency, however, often deform by only a few hundred nanometres.
The Stanford researchers made their nanopillars from silicon dioxide. They first created a metal mask on a quartz substrate by electron-beam lithography. Next, they carved the spots in the substrate using a technique called anisotropic reactive ion etching. The spots underneath the metal mask are protected from etching, explains Bianxiao Cui, and become vertical nanopillars.