Shear reversible cell/microsphere aggregate as an injectable for tissue regeneration

Injectable delivery systems have been widely used in tissue engineering as they can deliver cells into the body in a minimally invasive manner. In this study, it is hypothesized that microspheres with a similar size of cells could effectively form a shear reversible aggregate in the presence of cells and the aggregate could be useful to engineer tissues. Alginate microspheres are prepared by an emulsion method, followed by modification with a peptide containing the arginine-glycine-aspartic acid (RGD) sequence. RGD-modified alginate microspheres form an aggregate in the presence of chondrocytes, and the aggregation behavior is shear reversible. This cell/microsphere aggregate is useful to deliver chondrocytes into an animal model using a syringe, and effectively regenerates cartilage tissues in vivo.