Self-Assembled Toroidal-Spiral Particles: Parallel Pathways for Multi-Drug Release

Self-Assembled Toroidal-Spiral Particles: Parallel Pathways for Multi-Drug Release

Vishal Sharma¹, Magdalena Szymusiak¹, Hao Shen¹, Ludwig C. Nitsche¹, Ying Liu^1*

¹ Department of Chemical Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA.

 ^* To whom correspondence should be addressed. E-mail: liuying@uic.edu

Abstract

New concepts in chemotherapy focus on localized delivery of multiple drugs on independent schedules for synergistic effects. These concepts often involve complex techniques and/or harsh conditions for small molecules or drugs during fabrication. We describe self-assembly of polymeric particles, whereby competitive kinetics of viscous sedimentation, diffusion and cross linking yield a controllable toroidal-spiral (T-S) structure. Diffusion through these T-S channels and the polymer matrix offers parallel release pathways for molecules of different sizes. Precursor polymeric droplets form the T-S shape while sedimenting through a less dense, miscible solution and are then cross-linked using ultra violet light into solid particles. The dimensions of the channels are controlled by Weber number, Reynolds number, and viscosity ratio during impact on the surface and subsequent sedimentation. Self-assembly of these T-S particles occurs in a single step under benign conditions for delicate macromolecules, and appears conducive to scale up. Experimental and simulation data on release kinetics show sustained release from the internal channels of the T-S particle. The release of small molecules through these internal channels relies on diffusion, which can be tailored through channel length and width.