Nanomechanics of lung epithelial cells

Nanobiotechnology provides powerful tools for manipulating cells with nanometric resolution and with simultaneous measurement of force with pN resolution. We review the application of atomic force microscopy (AFM) and magnetic tweezers for probing cell nanomechanics. AFM measures the mechanical properties of the cell by indenting its surface by means of a flexible cantilever with a sharp tip at its end. Magnetic tweezers probe cell mechanics by twisting or pulling a magnetic microbead bound to the cell surface. The stress-strain relationship allows us to compute the complex shear modulus of the cell. Lung epithelial cells probed with AFM and magnetic tweezers exhibit a power-law dynamics with a weak exponent. This dynamics conforms to the rheology of soft glassy materials, suggesting that cytoskeleton internal disorder and matrix agitation could govern the mechanical behaviour of the cell.