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Updated: Jun 18, 2026

DNA Nanotubes as a Versatile Tool to Study Semiflexible Polymers
Published on: October 25, 2017
Buckling, stiffening, and negative dissipation in the dynamics of a biopolymer in an active medium
Norio Kikuchi1, Allen Ehrlicher, Daniel Koch
1Department of Physics, Centre for Condensed Matter Theory, Indian Institute of Science, Bangalore 560 012, India.
Abstract:
We present a generic theory for the dynamics of a stiff filament under tension, in an active medium with orientational correlations, such as a microtubule in contractile actin. In sharp contrast to the case of a passive medium, we find the filament can stiffen, and possibly oscillate or buckle, depending on both the contractile or tensile nature of the activity and the filament-medium anchoring interaction. We also demonstrate a strong violation of the fluctuation-dissipation (FD) relation in the effective dynamics of the filament, including a negative FD ratio. Our approach is also of relevance to the dynamics of axons, and our model equations bear a remarkable formal similarity to those in recent work [Martin P, Hudspeth AJ, Juelicher F (2001) Proc Natl Acad Sci USA 98:14380-14385] on auditory hair cells. Detailed tests of our predictions can be made by using a single filament in actomyosin extracts or bacterial suspensions.
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