(180ag) Interaction of Sedimenting Drops in a Miscible Solution – Formation of Heterogeneous Toroidal-Spiral Particles

Interaction of Sedimenting Drops in a Miscible
Solution ? Formation of Heterogeneous Toroidal-Spiral Particles

Magdalena Szymusiak¹,Vishal
Sharma¹, Hao Shen¹, Ludwig C. Nitsche¹, Ying
Liu¹*

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

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

Abstract

With a view
toward enabling eventual applications in multi-drug-delivery and chemotherapy,
we used the selfassembly of polymeric particles with
a novel internal structure. The well-defined toroidal-spiral (TS) channels form
due to drop interaction during their sedimentation in a miscible bulk solution,
and are solidified by photopolymerization. Such
particles would potentially offer an independent and quantitatively predictable
pathway for protein encapsulation and sustained release, in addition to
diffusion of smaller molecules through the polymer matrix. The generation of TS
particles by single drops has been studied first in which case the entrainment
of the bulk solution within the spiral-shaped channels offered a
mechanism for encapsulating active agents under benign flow conditions (low shear
with only an aqueous phase). The interaction of horizontally and vertically
displaced polymeric drops provides a better control of the amount of
encapsulation with the known volume of the drop and concentration of the active
compounds. Multiple drops
also offer the flexibility to encapsulate multiple active compounds without
concern of their mutual compatibility in one solution. Furthermore, the
understanding of multiple drop interaction is essential for mass production of
TS particles by using parallel and sequential arrays of sedimenting
drops.