Bio Dynamics Using Atomic Force Microscopy

Traditional AFM imaging has been restricted in studying the dynamic processes involved with cell mechanics due to the typically longer acquisition times required to obtain a single image which is usually on the order of minutes. With recent advances in high-speed AFM imaging such as those enabled by Bruker’s Dimension FastScan BioAFM, where images are now obtained in a matter of seconds, we have successfully begun to apply AFM imaging to investigate the mechanics of cell migration. Protrusion formation is one of the essential first steps in this process. The unique combination of high-resolution and high-speed AFM imaging has now allowed us to directly observe the formation and advancement of individual lamellipodia and fillipodia at the leading edge of live stem cells during migration.

Migrating stem cell

This Dimension FastScan BioAFM movie shows the leading edge of a migrating stem cell. Each AFM image in this times-series was collected at a rate of 40 seconds per frame at a resolution of 512 x 128 pixels. In the movie we see two lamellipodia extend in front of the cell, as well as the formation of smaller fillipodia. Then as the cell crawls forward we see a flow of membrane material to the cell front filling in the space between the lamellipodia. These are very classic stages of cell migration that have been traditionally only temporally resolved by optical microscopy techniques like we see in the phase contrast videos of stem cells. However, these optical techniques are limited in these studies as they cannot really resolve the small structures such as the individual fillipodia and lamellipodia on a single cell.  

Check out more videos from the FastScan Bio AFM!