Degradable polyesters constitute one of the most popular choices for biomedical applications, as they degrade to components present in the human metabolome, and thus get eliminated via natural pathways. In addition, the use of FDA-approved materials to build nanoplatforms can make more feasible their clinical translation. In the case of amphiphilic block copolymers, minor tuning of the hydrophobic segment (i.e. altering the ratio of one polyester to the other) can allow accessing unique architectures, as well as defining the physicochemical properties of the nano-assembly (e.g. softness of the material). A change in the physicochemical profile (e.g. Tg) is directly reflected on the behaviour of the polymer in water. For instance, reaching the vesicular morphology can potentially occur through a different mechanism. Aside from the polymer nature, the process of self-assembly is strongly affected by several physicochemical parameters. Starting from the most simple way to assemble particles, namely the top-down film hydration, the thickness of the film, as well as the shearing stress during the hydration process are all parameters demonstrated to affect both the speed of formation and the quality of particles size distribution. The question of controlling self-assembly with bottom-up techniques like solvent displacement becomes far more complex. This is due to the contribution of the solvent where the polymer is dissolved. Additionally, parameters like temperature, and the rate of phase addition have been demonstrated to play a pivotal role in guiding the assembly. The self-assembly profile of a series of PEGylated polyesters is investigated here employing both bottom-up and top down approaches. We show how experimental processing (e.g. choice of solvent) can exert control over the nanoparticle morphology while we also follow how different polyesters reach the vesicular morphology under a distinct growth mechanism.

Experimental study on the self-assembly of polyesters

2019 Fall National Meeting

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