To strengthen the colloidal network of fibril clusters adsorbed at the W/W interface, we separately added 0.15% sodium alginate and 0.15% fibril clusters from the droplet and continuous phases, and generated W/W emulsion through electrospray. After the alginate-laden dextran-rich droplets are sprayed into the cluster-laden PEG-rich continuous phase, the anionic sodium alginate molecules are complexed with cationic fibril clusters through electrostatic attraction at the W/W interface. As sodium alginate molecules continuously diffuse across the W/W interface and react with fibril clusters, a core-shell structured capsules are formed, until the completed consumption of the sodium alginate in the droplet phase. By transferring the capsules into the calcium chloride solution, the fibril cluster/alginate complexes are solidified into microcapsules (Fig. ). SEM observation confirms that the capsules are intact, composed of multilayered fibrils on their surface (Fig. ). These capsules with hollow chambers (Fig. ) can maintain stable in cell-culture medium for over several months.