Optical Tweezing of Cells with the NanoTracker 2: Manipulation and Force Measurements

Introduction

In the last decades, optical traps (also known as optical tweezers) employing highly focused laser beams to trap and manipulate objects on the nano- and microscale have proven to be versatile tools in many biological and biophysical studies. The technique relies on the transfer of momentum from light entering a refractive particle which allows its stabilization in a trapping potential. From particles in the tens of nanometers range up to whole cells, a variety of objects can be held and accurately positioned. With advanced setups like JPK's NanoTracker™ 2, forces acting on the trapped objects can be measured with high precision down to single piconewtons and below. This opens up a broad range of possible experiments in the context of cellular research. Some fundamental applications will be introduced in this note.

More detailed information on the tapping mechanism itself and the working principle of optical traps can be found in our technical notes (e.g. "Quantitative force measurements with optical tweezers: The JPK NanoTracker™")