Time-Resolved <i>In Situ</i> Small-Angle X-ray Scattering to Determine the Kinetics of Formation of Liquid Crystalline Structure in the Core of Polymeric Nanoparticles during and after Turbulent Mixing.

Abstract

The encapsulation of liquid crystalline phases, formed from biocompatible amphiphiles, into nanoparticles has emerged as a promising delivery strategy for hydrophilic and hydrophobic therapeutics. Strategies to characterize these delivery systems as a function of formulation parameters and aqueous environment post-manufacture are well-documented. A critical gap remains regarding the assembly kinetics and <i>in situ</i> dynamics of these systems using industrially relevant manufacturing techniques. Systematically investigating these characteristics is challenging: computational simulations are time-intensive and costly, while current <i>in situ</i> quantification techniques are limited in scalability and batch size. We here combine synchrotron small-angle X-ray scattering with Flash NanoPrecipitation, a scalable turbulent mixing technology, to capture time-resolved measurements of the formation of liquid crystal phases under nanoconfinement during and after nanoprecipitation. This technique reveals that self-assembly occurs in two steps, with internal liquid crystal self-assembly occurring on longer time scales (seconds to minutes) than initial nanoprecipitation (milliseconds) as a function of formulation parameters.