Aqueous Two-Phase Droplet-Templated Colloidosomes Composed of Self-Formed Particles via Spatial Confined Biomineralization.

A facile and green approach is developed for fabricating colloidosomes with well-controlled size and structure from the microfluidic-generated aqueous two-phase system (ATPS) emulsion droplet. Unlike other methods that rely on self-assembly of externally added colloidal particles at the emulsion interface, urease-mediated biomineralization induced by "drainage" is introduced to form CaCO3 particles at the alginate emulsion interface for preparing Ca-alg@CaCO3 colloidosomes. Two types of bioactive molecules (bovine serum albumin and catalase) can be encapsulated with high efficiency (>85%) because of the partitioning effect of the ATPS and high viscosity of alginate solution. The encapsulated bioactive molecules can be controllably released by regulating the compactness of colloidosomes. Moreover, after being freeze-dried or dried at 37 °C, the activity of catalase in colloidosomes is obviously higher than that in alginate hydrogels, which confirms that the Ca-alg@CaCO3 structure has strong protection for inclusions. We believe that the biocompatible and controllable Ca-alg@CaCO3 colloidosomes possess great potential applications in bioencapsulation for foods, daily chemicals, and synthetic protocell formation.