(449e) Measuring the Elasticity of Semiflexible DNA-Linked Colloidal Chains Via Thermal Fluctuations

Flexibility is a crucial parameter in determining the equilibrium configuration of microstructures. In this talk, we will focus on the influence of variable flexibility on the shape and morphology of DNA-linked colloidal chains. These multilink chains are comprised of magnetic colloidal particles which are linked together with DNA.

The flexural rigidity, or bending stiffness, is used to describe the chain's resistance to bending forces. We have previously shown that the properties of the linker molecules greatly influence the overall chain flexibility1. In particular, by adjusting the length of the linker molecule, we can tune the overall flexibility of the chain. We have recently constructed a technique to measure the flexural rigidity of a chain by observing its Brownian motion in an aqueous solvent. The measured flexural rigidities unveil a wealth of information about properties of linker molecules and the linking kinetics.

In this talk we will show that these linked colloidal chains often result is a chain with varying flexural rigidity along its backbone. We will compare these results with those of chain assumed to be a linear homogenous elastic filament2-4. We will also elucidate how the properties of the linker molecules and linking kinetics affect the overall chain elasticity.

1. Biswal SL, Gast AP. Mechanics of semiflexible chains formed by poly(ethylene glycol)-linked paramagnetic particles. Physical Review E 2003; 68: 021402/1-/9.

2. Goubault C, Jop P, Fermigier M et al. Flexible magnetic filaments as micromechanical sensors. Phys Rev Lett 2003; 91: 4.

3. Cebers A. Flexible magnetic filaments. Current Opinion in Colloid & Interface Science 2005; 10: 167-75.

4. Cebers A, Cirulis T. Magnetic elastica. Phys Rev E 2007; 76.