Direct, nano-rheological studies of in-plane lipid dynamics in model and native membranes
- Abstract number
- 59
- Presentation Form
- Poster
- DOI
- 10.22443/rms.mmc2023.59
- Corresponding Email
- [email protected]
- Session
- Poster Session Two
- Authors
- Dr William Trewby (1), Prof Kislon Voïtchovsky (1)
- Affiliations
-
1. Durham University
- Keywords
Nano-rheology, lipid dynamics, AFM,
- Abstract text
Lipids are now known to play an active part in supporting protein function, oncogenesis and disease signalling, in contrast to their previously-assumed passive character. Their assemblies in organelles such as lipid droplets are recognised as being crucial to the proper storage and transport of fats, and dysregulation can lead to severe pathologies including cardiovascular disease. The complex functions of lipids within the body are largely dependent on their in-plane motion, which governs the ability of biomembranes to restructure, as well as the transport of small molecules along and across the lipid layers.
Despite the significance of a holistic understanding of lipid dynamics, experimental techniques rarely have direct access to parameters such as friction or lipid mobility at a molecular level and over a broad range of timescales. Instead, the reliance on either equilibrium fluctuations, chemical modification of the target or experimentally friendly velocities results in spatially averaged measurements that cannot capture fine details of the local interactions encountered by diffusing molecules at the nanoscale.
Here, we develop a novel high-frequency shearing device that can be used to provide highly localised information about molecular mobility in unfunctionalized synthetic and native membranes. Crucially, the technique probes areas of ~10 nm2, allowing for direct energetic measurements on the scale of single proteins. We use this tool to investigate a range of membranes, highlighting non-linear diffusive behaviour that depends sensitively on velocity, confinement and composition. We also combine the technique with high-resolution atomic force microscopy imaging of a natural bovine eye lens to quantify the heterogeneous dynamics within the crowded membrane.