Surface coated paramagnetic microspheres can be physically aligned under the influence of a magnetic field and chemically linked by linker molecules into permanently linked linear chains. Our lab has been able to fabricate chains of 1ìm Streptavidin coated paramagnetic particles linked by either bis-biotin-polyethylene glycol (PEG) or bis-biotin-DNA linker molecules. The flexural rigidity or bending stiffness used to describe the chain's resistance to bending forces. We have previously shown how varying the length of the linker molecule results in chains of varying flexibilities [1]. We determined that a shorter linker molecule resulted in a very stiff chain. We have recently explored how the rigidity of the linker moleculer affects the macroscopic mechanics of the chain. This is done by fixing the contour length of the linker molecule and changing its persistence length. In this talk we will present our results and elucidate how the properties of the linker molecules affect the overall chain dynamics.

We characterize the flexural rigidities of these chains linked by different linker molecules by tracking and analyzing the image their Brownian motion. We also perform constrained Brownian dynamics simulation to relate fundamental properties of linker molecules, such as their contour lengths and persistence lengths, to the overall flexural rigidities of these chains.

1. Biswal, S.L. and A.P. Gast, Mechanics of semiflexible chains formed by poly(ethylene glycol)-linked paramagnetic particles. Physical Review E, 2003. 68(2 1): p. 021402/1-021402/9.