Material and biological characterization of 3D knitted bioresorbable poly (D,L-lactide) (PLA) and polycaprolactone (PCL) scaffolds for soft tissue regeneration: from fabrication to in vivo performance.

Background: Soft-tissue reconstruction is crucial in fields such as plastic surgery and oncology to address the repair of damaged tissues. Knitted scaffolds from bioresorbable copolymers, specifically poly(D,L-lactide) (PLA) and polycaprolactone (PCL), offer mechanical and biological properties that are essential for tissue engineering. This study assessed three-dimensional knitted scaffolds fabricated from melt-spun PLA and PCL multifilaments for soft tissue engineering applications. It examined the impact of the PLA/PCL ratio on the knitted scaffold structure, mechanical properties, and biological responses to determine the optimal composition for adipose tissue reconstruction.

Results: Knitted scaffolds fabricated with the PLA/PCL blends (PLA₇₀/PCL₃₀ and PLA₉₀/PCL₁₀) exhibited distinct mechanical and biological profiles. PLA₇₀/PCL₃₀ scaffolds with a higher PCL content showed enhanced elasticity and porosity, whereas PLA₉₀/PCL₁₀ scaffolds maintained better structural integrity and stiffness. Biological assays confirmed the biocompatibility of all scaffolds in vitro, with no cytotoxic effects. The scaffolds supported adipogenic differentiation in vitro, although PLA₇₀/PCL₃₀ exhibited slightly reduced efficacy. Vascularization was evident using chorioallantoic membrane assays, in which blood vessel formation and penetration were observed, regardless of the scaffold composition. In vivo implantation in rat models revealed effective adipocyte integration, structural stability, and minimal inflammatory response, with PLA₉₀/PCL₁₀ scaffolds outperforming PLA₇₀/PCL₃₀ in terms of vascularization and less macrophage infiltration of connective tissue.

Conclusion: PLA/PCL knitted scaffolds offer a promising solution for enhancing graft volume maintenance and improving long-term outcomes, with tunable mechanical properties and biodegradability. The PLA₉₀/PCL₁₀ scaffold is a superior candidate for adipose tissue reconstruction, balancing the structural stability with biological compatibility. These findings underscore the potential of PLA/PCL scaffolds for reconstructive surgery. Future studies should focus on scalability and long-term biocompatibility to facilitate clinical translation.