Quantitative gene expression of cartilage markers by chondrocytes in three ELP-HA hydrogel compositions with varied HA concentrations after 7 days of culture in chondrocyte growth medium. HA concentrations were varied from 1.5% to 5% while keeping hydrogel stiffness constant (∼350 Pa). (A) Aggrecan, (B) Sox 9, (C) type II Collagen, (D) type X Collagen, (E) matrix metallopeptidase (MMP13), and (F) type I collagen. Data are presented as average +/- standard deviation (n=3 per group). *p <0.1, **p<0.005 compared to ELP-1.5%HA group.