Knee osteoarthritis (KOA) remains a major clinical challenge due to the limited regenerative capacity of articular cartilage and the poor stability and bioavailability of therapeutic growth factors. In this study, we engineered a phosphatidylserine (PS)-modified RADA16-I self-assembling peptide nanocarrier for the encapsulation and sustained intra-articular delivery of fibroblast growth factor 18 (FGF18). Nuclear magnetic resonance (NMR)