Surface Modification of Porous Polycaprolactone for Enhanced Applications in Graded Implant Prototyping

This study focuses on developing of cost-effective, scalable polycaprolactone (PCL) substrates (electrospun (blend) fiber mats, 3D porous scaffolds, braided textiles, melt spun fiber mats and 3D prints), for implant prototyping, particularly through CS-g-PCL (chitosan-grafted PCL) modification via co-crystallization. While CS-g-PCL enables further functionalization, such as nanoparticle-based growth factor release, its synthesis was costly due to long purification times. This challenge was addressed by optimization of synthesis and purification conditions, increasing yield up to fivefold and supporting its use with PCL substrate modification. Interconnected 3D porous PCL scaffolds were fabricated through blending, annealing, and leaching. Blends with polyethylene oxide, sucrose, or NaCl were tested, all proving suitable. CS‑g-PCL modification via dip-coating improved functionality, blending it in reduced structural integrity due to increased solubility. Scaffold morphology and porosity were optimized by varying composition and processing parameters, evaluated via SEM, porosimetry, and XRM. Braided textiles and 3D porous PCL performed best overall in terms of mechanical strength, modifiability, and growth factor release. Electrospun mats had strong release efficiency but were limited by weak mechanical properties. CS-g-PCL modification was successfully visualized and quantified; however, effectiveness varied by scaffold type. Best results were seen in electrospun mats, braided textiles, and 3D porous PCL. Braided textiles and 3D porous scaffolds, modified with CS-g-PCL and growth factor systems, showed promising in vitro TGF‑β3 release and good cell viability. Although some findings from previous studies (e.g., increased cell vitality) were not replicated, no adverse effects were observed. Overall, interconnected 3D porous PCL and braided textiles emerged as the most promising scaffolds, combining fabrication ease, reliable CS-g-PCL modification, efficient growth factor release, and suitability for load-bearing implant applications.