Fabrication of hollow-centered sodium-alginate-based hydrogels embedded with various particles

We prepared shape-controllable, sodium alginate-based hydrogels containing various particles inside the hydrogels. Centrifugal injection method was employed to obtain smaller sized gels, compared to that fabricated by conventional method. A conventionally-fabricated gel beads were spherically-shaped, in which the shape was determined by the droplets of sodium alginate solution from syringe needle. The shape of the gels was easily manipulated to obtain hollow-cylindrical gels by simple use of embedding particles and by changing the concentration of sodium alginate, calcium chloride, and the embedding components. As a result, the hollow-centered gels with the unique shape were obtained.