Abstract: A composition comprising a glycosaminoglycan component, and one or more extracellular matrix components forming a precipitate with the glycosaminoglycan component, wherein the precipitate has a glycosaminoglycan to hydroxyproline ratio from about 1:10 to about 100:1. In particular, it is a GAG-rich composition with controllable and high glycosaminoglycan (GAG) content that mimics the extracellular matrix (ECM) of GAG-rich native tissues. Also provided is a method of making and using the aforesaid composition. Further provided is a method of treating a tissue disorder in a subject using the aforesaid composition. The composition may be used as scaffolds for applications such as microcarriers, 3D culture substrates, swelling agent, volume filling agent, replacement of nucleus pulposus, cartilage, and other GAG-rich tissues.