Osteochondral defects, involving the simultaneous damage of bone and cartilage tissues, remain one of the most difficult challenges in regenerative medicine. Current treatment methods often fail to restore the native structural and functional gradient between the rigid subchondral bone and the elastic cartilage, resulting in poor mechanical integration and limited long-term outcomes.
To address this issue, we have developed an innovative gradient composite biomaterial that mimics the natural bone–cartilage interface. The structure is based on a mechanically stable poly(lactic acid) (PLA) scaffold coated with sequential polymer–ceramic layers and polysaccharide. Within these layers, calcium phosphate ceramics are incorporated in a controlled gradient, from a high ceramic content at the bone-facing side to a polymer-rich surface mimicking cartilage.
This multilayered design supports osteogenic and chondrogenic cell adhesion and differentiation, enabling spatially controlled regeneration of both tissues. Additionally, the gradient layers can serve as carriers for therapeutic cells, growth factors, or bioactive molecules, providing localized and sustained release. The scaffold also enables in situ immunostaining of molecular markers, allowing non-invasive monitoring of tissue integration and healing progress.