Novel coaxial atomization processes for microfabrication of multi- layered biodegradable microcapsules

摘要

The coaxial atomization process was studied experimentally and theoretically to overcome the existing limitation in microencapsulation. The coaxial electrospray process and the coaxial flow focusing process were explored and a novel coaxial electro-flow focusing process that combined these two processes was proposed. This novel process formed a coaxial liquid jet in the core of a high-speed co-flowing gas stream under an axial electric field and the liquid jet eventually broke up into fine microcapsules. The effects of main process parameters on the formation of meniscus attached to the mouth of the coaxial needle were tested. A theoretical model was further implemented for instability analysis of the coaxial jet to guide the process control and optimization. As a result, stable cone-jet configurations in a wide range of process parameters were obtained and good morphologies of microcapsules were achieved. The reported research represents the first step toward quantitative control and optimization of the coaxial atomization process for microfabrication of multi-layered microcapsules in multimodal imaging and image-guided therapy.