Testing nano-scale mechanics

Let's have a look on mechanical testing. This is a very simple process, you can try it yourself. The only thing to do, is to poke something with your fingers and "check" its mechanical properties (stiffness). How is it? Soft, hard? Nano-mechanical testing of a single living cell, is the same process,... but instead your fingers, which would destroy hundreds or thousands of cells, regardless of sensing anything, the tip of an AFM is an ideal choice. You can see on the following short video, how living cells can be "poked"... :)

Upon gently poking living cells, their mechanical parameters can be measured harmlessly. As stiffness is altered in cancerous cells, cellular mechanics has great importance in cancer research. 

How it works 2

The second operation mode of the atomic force microscope, is different: basically the cantilever oscillates near its resonant frequency, and the amplitude of this oscillation is detected by the same laser/photodiode system. Here is a quick movie how it works:

A versatile nanomechanical tester ... the AFM

Single cell nanomechanics and manipulation is not a trivial task. Among the available techniques to address and measure nanomechanical parameters, the most versatile is the atomic force microscope. The microscope uses a very sharp “tip” to scan or test the desired sample’s surface. Soon after its invention, it became the most reliable and accurate nanoforce-tool in the research of cellular bio-nanomechanics, due to the ability to operate in liquid environment and at human body temperature. Nevertheless, the ability of nanometer scale mechanical manipulation and measurement in a liquid environment on living cells is an absolute advantage compared to conventional cellular imaging techniques. It has two basic operation modes, one being the simple contact mode: the sharp tip is simply feels the surface of the desired specimen. Here is a short video of how it works.