Over 20 million people in Europe suffer from osteoarthritis which can lead to extensive damage to the knee and hip cartilage. Stem cells offer a promising way forward but a key challenge has been to design a ‘smart material’ that is biologically effective for cartilage tissue regeneration. Now researchers have identified a blend of naturally occurring fibers such as cellulose and silk that makes progress towards affordable and effective cell-based therapy for cartilage repair a step closer.