Polymer-based porous microcarriers as cell delivery systems for applications in bone and cartilage tissue engineering

For tissue regeneration or repair, a suitable temporary scaffold needs to be constructed for delivering regenerative cells to damaged or diseased tissue. Scaffold types are currently categorised into 3D monolithic scaffolds, hydrogels, and microcarriers. Among these scaffolds, microcarrier systems offer an attractive method for cell amplification and enhancement of phenotype expression, and they have emerged as powerful injectable carriers to repair and reconstruct irregular defects in tissues and organs. In this article, several important issues related to polymeric porous microcarriers for tissue engineering are reviewed. The properties of porous microcarriers, including surface chemistry, pore structure, typical particle size, and specific density, and the corresponding effects on cell cultures are discussed. The fabrication techniques and biomaterials investigated for porous microcarriers are summarised, and their advantages and disadvantages are outlined. Recent advancements in the application of porous microcarriers, including bone and cartilage tissue engineering, are also presented.