Synthesis and Shape Control of Uniform Polymer Microparticles by Tailored Adsorption of Poly(ethylene oxide)‐b‐Poly(ε‐caprolactone) Copolymer

Abstract

This paper introduces a straightforward and robust polymerization method for the synthesis of uniform polymer microparticles having controlled surface chemistry as well as tailored particle shapes. Uniform polystyrene (PS) microparticles are produced by dispersion polymerization, in which amphiphilic poly(ethylene oxide)‐b‐poly(ε‐caprolactone) (PEO‐b‐PCL) copolymers anchor on to the growing polymer particles and stabilize them by steric repulsion. We have observed that, when PEO‐b‐PCL copolymers are incorporated at the proper concentration range, the total number of particles remains unchanged after the formation of primary particles, which is essential for maintaining size uniformity. Otherwise, nonuniform PS microparticles are produced mainly as a result of the coagulation or secondary formation of particles. To show the diversity of our particle synthesis technology, shape‐controlled microparticles, such as dimples and Janus particles, are also produced by using temperature‐mediated swelling and phase separation. Finally, we show that PEO‐b‐PCL copolymers play a key role in regulating the surface wettability of the seed particles, thereby facilitating the formation of anisotropic microparticles.

Microparticles, Microspheres, and Microcapsules for Advanced Drug Delivery

“…These microparticles with a certain shape and phase anisotropy, created by alloying the distinct properties (hydrophilic, hydrophobic) of the separated excipients, are used as multifunctional imaging probes and sensors [6,7]. The anisotropic response to external signals has also been exploited in the preparation of color-changing traffic signals.…”

Polydopamine Nanomaterials for Overcoming Current Challenges in Cancer Treatment

“…According to the published work in the last few years, nanoparticles with anisotropic morphologies have become a fast-moving research topic in biomedicine [ 38 ]. In order to overcome the limitations associated with the regular isotropic particles within biomedical applications, a number of anisotropic morphologies have been engineered: triangles, dimple-shaped, cubes, rods, discs, stars, walnuts, bowls/cups, etc., [ 39 , 40 , 41 , 42 , 43 , 44 ]. Research in the field of nanoparticles-based drug delivery systems shows that due to the morphology of certain anisotropic particles, minimal repulsive interactions with cancer cells occur, thus accelerating their cellular uptake in cancer cells, thereby ensuring efficient and fast tumor penetration, which is an important property of an efficient drug nanocarrier [ 45 , 46 , 47 , 48 ].…”