Signatures of glassy dynamics in highly ordered lipid bilayers with emergence of soft dynamic channels.

This article focuses on characterizing spatial and dynamic heterogeneity within the liquid-ordered (Lo) phase of biological lipid membranes using molecular simulations and advanced analytical frameworks. Employing the non-affine displacement (NAD) parameter, originally developed for amorphous solids, the study reveals that highly ordered lipid bilayers composed of DPPC, DOPC, and cholesterol exhibit glass-like dynamics with transient "soft fluid channels" that facilitate molecular mobility despite tight packing. Through analyses including mean squared displacement, overlap functions, dynamic susceptibility, and Van Hove functions, the research demonstrates Arrhenius-like relaxation behavior indicative of strong glass-forming properties in the Lo phase near physiological temperatures. These findings suggest that dynamic heterogeneities and localized fluid channels within ordered membrane domains may play a critical role in biological functions such as protein interactions and signaling.