Role of α and β relaxations in collapsing dynamics of a polymer chain in supercooled glass-forming liquid.

Understanding the effect of glassy dynamics on the stability of bio-macromolecules and investigating the underlying relaxation processes governing degradation processes of these macromolecules are of immense importance in the context of bio-preservation. In this work, we have studied the stability of a model polymer chain in a supercooled glass-forming liquid at different amounts of supercooling in order to understand how dynamics of supercooled liquids influence the collapse behavior of the polymer. Our systematic computer simulation studies find that, apart from long time relaxation processes (α relaxation), short time dynamics of the supercooled liquid, known as β relaxation, is also correlated with the stability of the model polymer. We also show that anti-plasticizing effect found in this context can be rationalized using the β-relaxation process and how it is modified due to changes in the specific interactions between the biomolecules and the solvent molecules or changes in the local packing around the biomolecules. Our results corroborate with other recent results which suggest that it is important to take in to account both the α and β relaxation times while choosing appropriate bio-preservatives. We believe that our results will have implications in understanding the primary factors in protein stabilization in the context of bio-preservation.