Silicones are widely used polymers in areas as diverse as electronics, household uses, and medicine. Microspheres made from silicones could have a wide range of possible applications, for example for sensors, chromatography, and drug delivery. Synthesis of such spheres is usually achieved using emulsion polymerization, but the particles are relatively large and have a wide distribution of sizes.
Kenneth S. Suslick, University of Illinois at Urbana-Champaign, IL, USA, and colleagues have prepared micrometer-sized polydimethylsiloxane (PDMS) microspheres (pictured) with a narrow size distribution by ultrasonic spray pyrolysis (USP). The approach uses ultrasound to generate a mist of polymer precursor, which is carried through a heated tube by an inert gas.
The resulting microspheres show minimal aggregation and have a low cytotoxicity. The researchers were able to include magnetic Fe3O4 nanoparticles during the synthesis to give magnetic microspheres. They also sucessfully doped the microspheres with a fluorescent dye (Nile red) as a proof-of-concept for imaging applications. The improved, easy synthesis can also be applied to other silicones. Drug delivery studies using more polar substrates are underway.
- Magnetic, Fluorescent, and Copolymeric Silicone Microspheres,
Jacqueline M. Rankin, Nitin K. Neelakantan, Kimberly E. Lundberg, Elissa M. Grzincic, Catherine J. Murphy, Kenneth S. Suslick,
Adv. Sci. 2015.