Mechanical and Electro-Mechanical Stimulation in Cartilage Tissue Engineering

Cartilage tissue engineering seeks to restore or replace damaged articular cartilage by harnessing the body’s natural repair mechanisms and by recreating the complex mechanical environment of a joint. Mechanical stimulation, delivered through dynamic compression, shear or tensile loading, mimics the physiological forces experienced by chondrocytes in vivo and drives matrix synthesis, organisation and maturation. Electro-mechanical approaches extend this paradigm by embedding piezoelectric or conductive materials within scaffolds or by applying direct electrical currents to cell populations. Such stimuli activate mechanotransduction and electro-responsive signalling pathways, upregulating key chondrogenic factors, enhancing extracellular matrix deposition and improving the mechanical properties of neo-tissues. Bioreactor platforms have evolved to provide precise, automated control of loading regimes, enabling systematic optimisation of the magnitude, frequency and duration of both mechanical and electrical cues. Together, these strategies offer a route to generate durable, hyaline-like cartilage constructs with potential application in osteoarthritis treatment, traumatic injury repair and joint arthroplasty, addressing a global burden of disease marked by limited intrinsic healing and high socioeconomic impact.

Research from Nature Portfolio

Researchers have introduced an injectable, biodegradable piezoelectric hydrogel comprising electrospun poly-L-lactic acid nanofibres within a collagen matrix. Activated by external ultrasound, this material generates localised electrical signals that enhance stem cell migration, drive secretion of chondrogenic growth factors and foster hyaline cartilage formation in a rabbit osteochondral defect model, yielding tissue with mechanical properties approaching native cartilage. Innovative bioreactor technology has enabled precise uni- and biaxial loading of human articular chondrocytes encapsulated in gelatin-methacryloyl and hyaluronic acid-methacrylate hydrogels. Intermittent biaxial stimulation upregulates hyaline collagen expression and promotes accumulation of characteristic extracellular matrix, demonstrating the necessity of controlled mechanical regimes for optimising engineered cartilage. Electrotherapeutic strategies have shown that direct electrical stimulation of mesenchymal stem cells, in the absence of exogenous growth factors, induces Ca2+ oscillations and TGF-β1 signalling, triggering condensation and differentiation into hyaline-like chondrocytes, thereby offering a growth-factor-free route to cartilage regeneration.

Mechanical and Electro-Mechanical Stimulation in Cartilage Tissue Engineering publication trend

The graph below shows the total number of articles in mechanical and electro-mechanical stimulation in cartilage tissue engineering across all publications each year (not limited to Nature Index journals).

Technical terms

Piezoelectric hydrogel: A polymeric scaffold that converts mechanical forces into electrical signals to stimulate cells.

Mechanotransduction: The process by which cells sense and convert mechanical stimuli into biochemical responses.

Bioreactor: A system that provides controlled mechanical or electrical stimulation to cell-seeded constructs under defined culture conditions.

Hydrogel: A water-swollen polymer network used to support cell growth and differentiation in three dimensions.

Chondrogenesis: The differentiation of progenitor cells into cartilage-producing chondrocytes and the subsequent formation of cartilage matrix.

Mesenchymal stem cell: A multipotent progenitor capable of differentiating into bone, cartilage and other mesenchymal tissues under appropriate stimuli.

References

1. Injectable and biodegradable piezoelectric hydrogel for osteoarthritis treatment. Nature Communications (2023).
2. A novel bioreactor system for biaxial mechanical loading enhances the properties of tissue-engineered human cartilage. Scientific Reports (2017).
3. Electrical stimulation drives chondrogenesis of mesenchymal stem cells in the absence of exogenous growth factors. Scientific Reports (2016).
4. Regeneration of Humeral Head Using a 3D Bioprinted Anisotropic Scaffold with Dual Modulation of Endochondral Ossification. Advanced Science (2023).
5. Progress in biomechanical stimuli on the cell-encapsulated hydrogels for cartilage tissue regeneration. Biomaterials Research (2023).