Shear force imaging of soft samples in liquid using a diving bell concept

Abstract

We present a reliable and easy-to-use system, with a perfect analogy to a diving bell, to perform tuning fork based shear force microscopy on soft cells in liquid. Using the diving bell concept the tuning fork vibrates in air, while the tip is immersed in solution. In this way Q factors of 200 and higher in liquid are routinely obtained. The force feedback is reliable and stable over hours requiring a minimum adjustment of the set-point during imaging. With this system, tip–sample interaction forces are kept below 350 pN, enabling us to image soft dendritic cells in a buffer solution.