Speaker
Description
Introduction
The field of regenerative medicine increasingly demands scalable, patient-specific soft tissue constructs. While hydrogel-based bioprinting provides a favorable environment for cell viability, it often lacks mechanical integrity - especially critical for replicating the elastic nature of soft tissues. Traditional scaffold-integrated bioprinting has improved structural support but remains largely focused on hard tissue applications due to limited flexibility. To overcome these limitations, we introduce 3D-Melt-Spin-Bioprinting (MSB) - a novel fabrication platform that synergizes textile engineering with drop-on-demand bioprinting to create highly elastic, mechanically tunable scaffolds suitable for soft tissue regeneration.
Materials and Methods
MSB scaffolds were fabricated from various polymers including PLA, TPU, PETG, and PCL. The process enabled precise control over fiber diameter (down to 50 µm), porosity, and mechanical properties, achieving elastic moduli between 0.7 and 212 MPa. TPU scaffolds demonstrated exceptional stretchability (up to 200%) and resilience under cyclic loading. Human mesenchymal stem cells (hMSCs) were printed into these scaffolds using bioinks at a concentration of 1 × 10⁶ cells/ml. Scaffold-bioink compatibility was analyzed via wettability, morphology (actin/DAPI staining), proliferation (CTB assay), and rheological profiling of the bioink. To evaluate the potential for differentiation into multiple cell lines, hMSCs were differentiated into adipogenic, osteogenic and chondrogenic lineages under adapted culture conditions (in Collagen I gels or by spheroid culture). Differentiation was evaluated by histologic staining and qPCR analysis.
Results
MSB technology enabled the fabrication of 1–5 cm³ scaffolds with defined architecture and high elasticity. TPU-based scaffolds outperformed other materials in fatigue resistance and sustained mechanical integrity. The fabricated scaffolds were compared with warp-knitted structures of similar size and density. Bioprinting into PCL scaffolds, followed by culture under varying media conditions, demonstrated effective cellular integration and robust differentiation of hMSC into adipogenic, chondrogenic, and osteogenic lineages. Real-time qPCR and histological staining confirmed expression of lineage-specific markers. For scalability, a custom DLP-printed perfusion bioreactor was developed. Within this system, multiple hMSC islands, cultured in 1 cm³ constructs, maintained viability and proliferation under dynamic conditions.
Discussion
This study presents MSB as a flexible, scalable, and biocompatible platform for soft tissue engineering. The textile-like fabrication process provides unique advantages - precise architectural control and elasticity - unavailable in traditional scaffold or hydrogel systems alone. Trilineage differentiation within these constructs highlights the system's regenerative potential. While the current design addresses many challenges in soft tissue biofabrication, further development is needed to support vascularization for larger tissue volumes. Early experiments incorporating sacrificial bioprinted channels show promise. Future work will focus on integrating endothelial cells (e.g., HUVECs) to facilitate vascular network formation and optimizing long-term culture within dynamic bioreactors.
Conclusion
3D-Melt-Spin-Bioprinting offers a robust and versatile platform for generating personalized, elastic scaffolds capable of supporting complex tissue regeneration. The successful integration and differentiation of hMSCs underscore its potential for clinical applications in soft tissue repair. Ongoing research aims to enhance vascularization and functional tissue maturation to fully realize its therapeutic utility.
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