Osteochondral Tissue Engineering Strategies

Osteochondral tissue engineering seeks to restore the integrated structure and function of articular cartilage and the underlying subchondral bone. The inherent gradient of mechanical stiffness, biochemical composition and cellular phenotypes across the cartilage–bone interface presents a critical design challenge. Contemporary approaches harness biomaterials with spatially controlled properties, cellular therapies and biofabrication techniques to mimic the zonal architecture of native tissue. Scaffold designs range from bilayer and trilayer constructs to gradient matrices that seamlessly transition from a cartilage‐mimetic region enriched in glycosaminoglycans and collagen type II to a bone‐mimetic region incorporating mineral components and osteogenic cues. Strategies employ natural or synthetic polymers, composite ceramics and supramolecular hydrogels, often combined with stem cells and growth‐factor delivery. Advanced manufacturing, particularly extrusion‐based and multi‐nozzle three‐dimensional printing, enables patient‐specific geometries and localised presentation of biochemical signals. Emphasis on interfacial integration, mechanical matching and controlled biodegradation has driven preclinical success in small and large animal models. Translation towards clinical application requires scalable fabrication, long‐term safety and functional restoration under load‐bearing conditions.

Research from Nature Portfolio

Recent studies have demonstrated the feasibility of fabricating full‐thickness osteochondral substitutes via combined plotting of a cell‐laden hydrogel and a mineralised phase. A dual‐phase construct comprising an alginate–methylcellulose bioink with embedded chondrocytes and a calcium phosphate cement matrix was shown to recreate the calcified cartilage region. Cells retained high viability during printing and culture, underwent redifferentiation and produced cartilage‐specific extracellular matrix components. The proximal mineralised zone modulated ionic exchange to support chondrogenic matrix deposition while maintaining a clear transition between cartilage and bone regions. This approach underlines the potential of compartmentalised bioprinting to engineer functionally graded osteochondral grafts ready for in vivo evaluation.

Research from all publishers

Innovations in gradient scaffold design have emphasised bioinspired transitions in porosity, composition and growth‐factor distribution. A recent scaffold incorporated continuous gradients of pore size, bioactive ceramics and osteochondrogenic factors to mimic the native osteochondral interface. This construct directed cell distribution and lineage commitment, promoting simultaneous cartilage and bone regeneration in preclinical defect models.

Another study developed an extracellular matrix‐mimicking scaffold composed of modified polysaccharides and polypeptides, engineered to form reversible and covalent networks. Zone‐specific incorporation of chondrogenic and osteogenic drugs created discrete microenvironments, resulting in formation of hyaline‐like cartilage with lacunae structure and dense subchondral bone with high mineral density in rabbit defects. The bioinspired design emphasises precise spatial control over biochemical and mechanical cues to achieve heterogeneous tissue repair.

Osteochondral Tissue Engineering Strategies publication trend

The graph below shows the total number of articles in osteochondral tissue engineering strategies across all publications each year (not limited to Nature Index journals).

Technical terms

Osteochondral: Relating to both cartilage and underlying bone, especially at joint surfaces.

Scaffold: A three‐dimensional structure designed to support cell attachment, growth and tissue formation.

Gradient scaffold: A biomaterial that exhibits continuous variation in composition or properties to mimic tissue interfaces.

Extracellular matrix (ECM): The network of proteins and polysaccharides that provides structural and biochemical support to cells.

Chondrogenesis: The process of cartilage formation by differentiation of progenitor cells into chondrocytes.

References

1. Bioinspired gradient scaffolds for osteochondral tissue engineering. Exploration (2023).
2. Enhanced osteochondral repair with hyaline cartilage formation using an extracellular matrix-inspired natural scaffold. Science Bulletin (2023).
3. Osteochondral Regeneration with 3D‐Printed Biodegradable High‐Strength Supramolecular Polymer Reinforced‐Gelatin Hydrogel Scaffolds. Advanced Science (2019).
4. Osteochondral tissue engineering: scaffolds, stem cells and applications. Journal of Cellular and Molecular Medicine (2012).
5. 3D bioprinting dual-factor releasing and gradient-structured constructs ready to implant for anisotropic cartilage regeneration. Science Advances (2020).
6. 3D Bioprinting of osteochondral tissue substitutes – in vitro-chondrogenesis in multi-layered mineralized constructs. Scientific Reports (2020).