Centres for Doctoral Training

The Biophysics of knotted DNA

Supervisors:

Sean Colloms, MVLS, School of Molecular Biosciences 

Manlio Tassieri, School of Engineering

Project summary: 

DNA can become knotted, and these topological entanglements can interfere with genome function, yet their physical behaviour remains poorly understood. This interdisciplinary PhD will investigate the biophysics of DNA knots across scales, from single molecules to entangled DNA solutions, combining molecular biology, optical tweezers and advanced microrheology.

Using site-specific recombination, the student will generate defined knotted DNA molecules and probe how knot topology influences elasticity, force transmission, friction and relaxation dynamics at the single-molecule level. Complementary studies on DNA solutions will explore how molecular topology shapes collective viscoelastic behaviour and emergent soft-matter properties.

The project brings together expertise in DNA topology, polymer physics and microrheology to establish a new framework linking molecular entanglement to mechanics. The student will receive training in cutting-edge biophysical methods, including optical trapping, microfluidics, broadband microrheology and quantitative modelling.

This project offers an exciting opportunity to work at the interface of molecular biosciences, engineering and soft matter physics, with relevance to chromosome biology, genome stability and the physics of topological materials.