Extracellular Vesicles-Enhanced 3D (Bio)Printing for Bone Regeneration: A Systematic Review

Three-dimensional (3D) (bio)printing has emerged as a relevant approach in bone tissue regeneration, enabling the precise fabrication of biomimetic scaffolds. The incorporation of extracellular vesicles (EVs) into 3D-(bio)printed constructs represents a promising cell-free strategy to enhance bone regeneration. EVs, as natural mediators of intercellular communication, contribute to osteogenesis, angiogenesis, and immune modulation. This review aims to evaluate current evidence on the use of EVs-enhanced 3D (bio)printing for bone regeneration. The literature search was conducted across different databases. <i>In vitro</i> and <i>in vivo</i> studies using EVs-containing (bio)printed constructs to assess osteogenic differentiation and/or bone regeneration were included. Out of 552 articles, 35 met the inclusion criteria. Most EVs were derived from bone marrow mesenchymal stem cells and were incorporated into scaffolds either before or after printing. Extrusion-based bioprinting was the most commonly used method. Nearly all studies reported enhanced osteogenic differentiation and bone formation in EV-treated groups, underscoring their therapeutic potential. EVs-based bioinks retain the regenerative benefits of stem cells while avoiding challenges associated to cell-based therapies. Despite encouraging results, standardization in EV isolation, storage, and delivery remains crucial for clinical translation. This review highlights the growing significance of EVs in regenerative medicine and identifies key areas for future research and development.