Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 8: Cell Motility: Neuronal Growth

AKB 8.1: Talk

Tuesday, March 28, 2006, 10:15–10:30, ZEU 260

Optical Neuron Guidance and Growth Cone Motility — •Daniel Koch, Timo Betz, Allen Ehrlicher, Michael Gögler, Björn Stuhrmann, and Josef Käs — Institut for Soft Matter Physics, University of Leipzig, Linnestr. 5, 04103 Leipzig, Germany

Understanding and controlling neuronal growth is a main research focus in the life sciences. All molecular stimuli for neuronal growth eventually address the polymeric cytoskeleton of the growth cone, a highly motile structure at the tip of an advancing neurite. However, the detailed molecular mechanisms underlying growth cone motility still need to be resolved. We have shown that optical forces induced by a highly focused infrared laser beam influence the motility of a growth cone by biasing the polymerization-driven intracellular machinery. In actively extending growth cones, a laser spot placed at specific areas of the neurite’s leading edge affects the direction taken by a growth cone. In an optical tweezers setup simultaneous phase contrast and fluorescence imaging, real-time shape detection, and automated laser irradiation are combined to control growth cone motility. Additionally we use high resolution edge detection in combination with a cross-correlation algorithm to extract the actin cytoskeletal dynamics in a growth cone in order to shed light on the mechanisms underlying optical neuron guidance. These novel techniques allow the investigation and manipulation of a natural biological process, the cytoskeleton driven morphological changes in a growth cone, with potential applications in the formation of neuronal networks and in understanding growth cone motility.