Bioprinting-based approaches for tendon reconstruction: A decade of advancement

Table 2 Principal advances and remaining challenges in tendon bioprinting

Aspect	Advancement	Impact
Bioprinting techniques	Extrusion, laser-assisted, and inkjet approaches with improving control of spatial deposition	Supports fabrication of organised tendon-like and interface constructs
Bioink development	Collagen-, gelatin-, fibrin-, and ECM-derived bioinks combined with synthetic reinforcement	Balances biological activity with structural stability
Biological integration	Cell-laden and tissue-specific bioinks; ADMSCs and MSCs printed within the bioink; distinguished from constructs seeded after fabrication	Supports zonal organisation and tendon-bone interface regeneration in preclinical models
Preclinical evidence	Rabbit and rat tendon-to-bone models using multilayered or gradient constructs (Table 1)	Improved histological organisation and mechanical performance vs repair-only controls; relative contribution of architecture, bioink and cells not yet separated; human efficacy unestablished
Technical challenges	Vascularisation, in vitro mechanical properties, in vivo durability under cyclic loading, reproducibility, scale-up	Research focuses on vascular strategies, robust composite constructs, and reproducible workflows
Clinical and regulatory	Classification as device vs cell-based advanced therapy; potency, sterility and cell-source governance; RMAT and ATMP pathways; cost-effectiveness	Translational barriers distinct from technical ones; no bioprinted tendon construct has yet reached clinical evaluation

ADMSCs: Adipose-derived mesenchymal stem cells; ATMP: Advanced Therapy Medicinal Product; ECM: Extracellular matrix; MSCs: Mesenchymal stem cells; RMAT: Regenerative medicine advanced therapy.