Fabrication of hollow poly(lactic acid) microcapsules from microbubble templates.

Hollow microcapsules are expected to be integral components of drug delivery systems in medical and pharmaceutical applications. Among the methods studied, the bubble template method (Makuta et al. Mater. Lett. 2009, 63, 703-705) should easily fabricate uniform hollow microcapsules covered with biodegradable polymers. In this study, we clarified the two conditions required to fabricate uniform hollow microcapsules using the bubble template method: the stability of uniformly sized microbubbles in a liquid droplet and the release of hollow microcapsules from the droplet. Furthermore, our experiments evaluated the radius distributions of template microbubbles and fabricated hollow poly(lactic acid) microcapsules.