Biodegradable porous beads and their potential applications in regenerative medicine

This article briefly reviews recent developments in the fabrication of biodegradable porous beads and their potential applications as cell carriers in regenerative medicine. The porous beads can be fabricated from natural (e.g., chitosan, alginate, and collagen) and synthetic (e.g., PLGA and PCL) polymers, as well as inorganic materials (e.g., calcium phosphates). The highly porous structure facilitates not only cell seeding and migration but also transportation of nutrients/oxygen and metabolic wastes, leading to high levels of cell density and viability. The ability to directly inject a suspension of cell-loaded beads using a needle allows for delivery of target-specific cells to the site of defect or disease without surgical incision for tissue regeneration. Comparative studies of porous and non-porous beads clearly show the superiority of porous beads in terms of viability, proliferation, and differentiation of cells, as well as injectability of cell/bead constructs.