The effect of NaCl on the self-assembly of elastin-like block co-recombinamers: Tuning the size of micelles and vesicles

Herein we present a study of the effect of the addition of NaCl on the size and shape of thermally driven elastin-like block co-recombinamer (ELbcRs) self-assembled nano-objects. Many researchers are currently using NaCl to tune the transition temperature (Tt) of elastin-like recombinamers (ELRs). However, this method is used without a complete understanding of the potential changes in the self-assembly process that might result. Therefore, although salts other than NaCl are used for comparison in this study, the main effort is directed towards the effect of NaCl as this salt is widely and routinely used to control Tt in ELR purification protocols and their applications. Dynamic light scattering (DLS) was used to follow the formation and determine the size of the nano-objects assembled, whereas static light scattering (SLS) was performed to study the molecular weight and gyration radius of the aggregates. Cryo-transmission electron microscopy (Cryo-TEM) was used to corroborate the data obtained by light scattering. These results support the use of NaCl as a highly interesting means of controlling the dimensions of ELbcR-based self-assembled nanoparticles in aqueous solution.