(717a) 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.