(427f) Visualizing and Predicting the Buckling of Semiflexible Chains

The compression and buckling of semi-flexible filaments, such as F-Actin and microtubules, are necessary for the mechanical stability and transport in cellular systems. Here we present results on the buckling instabilities in model semi-flexible chains. Micron-sized paramagnetic particles can be aligned using a magnetic field and linked together with DNA to form model semi-flexible chains. A magnetic field is applied to compress and buckle these chains. Chains rotate and deform under the influence of magnetic, viscous and elastic stresses. We take advantage of the micron size scale of the colloids and image chain buckling with details using optical microscope.

The buckling behaviors can be divided into two stages. Initially, buckling shows periodic structures followed by a conformational rearrangement into quasi-stable structure, such as U-shapes, S-shapes and other complex shapes. In the initial stage of chain buckling, the size of chains exhibits a great change. We discuss the effect of magnetic field strength and flexibility of chains having on the rapid change of chain size. Different chain properties and buckling field strength also affect the conformation of quasi-stable structures. We introduce a way to predict the overall size and detailed structures of the equilibrium shape of buckling.