In situ synthesis of twin monodispersed alginate microparticles

By applying the microfluidic emulsification and sorting processes, the formation of twin monodispersed droplets can be achieved in one step. The purpose of this study was to accurately separate the smaller of the twin droplets from the larger one to obtain two monodispersed microparticles. A bi-T-junction hybrid microchannel design was employed to control both emulsification and separation. The results show that the droplet sizes are comparable to the channel diameter and can be tuned by varying the shear rate of the oil phase relative to the aqueous phase. Due to the fact that the separation efficiency is close to 100% in this system, both of the collected larger and smaller droplets are highly monodispersed (RSD < 2% and 6%, respectively), and have high reproducibility. In addition, the proposed microfluidic device was employed to present a facile one-step synthetic approach for the preparation of twin monodispersed alginate microparticles entrapping quantum dots and Fe3O4 nanoparticles. The proposed microfluidic chip is capable of generating relatively uniform twin microparticles with sizes that can be well controlled. It is a simple, low cost, and high throughput process. In the future this apparatus could be applied to manufacture various twin monodispersed composite microvehicles to act as a smart drug delivery system.