Meniscal injuries are among the most common disorders affecting the knee joint and remain a major clinical challenge due to the limited intrinsic healing capacity of the meniscus, particularly in its avascular inner zone. Current treatments, including partial meniscectomy and meniscal repair, often fail to restore full function and may increase the risk of long-term joint degeneration and osteoarthritis. In this context, there is a clear need for alternative strategies capable of providing a functional meniscal substitute. This thesis aimed to develop a hydrogel-based, 3D-printed scaffold for full meniscus replacement using acrylate-endcapped urethane-based polyethylene glycol (AUP) macromers. These synthetic, photo-crosslinkable polymers were selected for their tunable chemical composition and their potential to generate scaffolds with adjustable physicochemical and mechanical properties. The central hypothesis was that combining tailored polymer chemistry, controlled scaffold architecture, and suitable fabrication techniques could yield constructs that better approximate the native meniscus while remaining reproducible and processable. To test this hypothesis, several fabrication routes were explored, including extrusion-based 3D printing, injection-based indirect manufacturing, and digital light processing (DLP). Across these approaches, the effects of polymer molar mass, functionality, concentration, and scaffold architecture on swelling behavior, gel fraction, morphology, and compressive mechanical performance were systematically investigated. The results showed that both material composition and scaffold design strongly influenced the final properties of the constructs. Increased polymer concentration and higher functionality generally produced stiffer networks, while architectural parameters such as pore size, strut diameter, and printing pattern significantly affected compressive response. DLP further enabled the fabrication of scaffolds with improved geometric fidelity and reproducibility. In addition, this thesis examined the influence of dehydration and post-processing on scaffold performance. Different drying methods significantly altered scaffold microstructure, swelling capacity, and compressive properties after rehydration, demonstrating that post-processing is not merely a practical handling step but an important parameter in scaffold design. Overall, this work demonstrates that AUP-based hydrogels represent a versatile platform for the development of porous, reproducible, and mechanically tunable scaffolds for meniscus replacement. While the obtained constructs showed promising static mechanical properties, fatigue resistance under prolonged cyclic loading remains a key limitation for future clinical translation. Nevertheless, this thesis provides a strong foundation for the further development of clinically relevant synthetic scaffolds for full meniscus replacement.
Development of a Hydrogel-Based 3D Printed Scaffold for Full Meniscus Replacement
MEAZZO, MARTINA
2026-06-25
Abstract
Meniscal injuries are among the most common disorders affecting the knee joint and remain a major clinical challenge due to the limited intrinsic healing capacity of the meniscus, particularly in its avascular inner zone. Current treatments, including partial meniscectomy and meniscal repair, often fail to restore full function and may increase the risk of long-term joint degeneration and osteoarthritis. In this context, there is a clear need for alternative strategies capable of providing a functional meniscal substitute. This thesis aimed to develop a hydrogel-based, 3D-printed scaffold for full meniscus replacement using acrylate-endcapped urethane-based polyethylene glycol (AUP) macromers. These synthetic, photo-crosslinkable polymers were selected for their tunable chemical composition and their potential to generate scaffolds with adjustable physicochemical and mechanical properties. The central hypothesis was that combining tailored polymer chemistry, controlled scaffold architecture, and suitable fabrication techniques could yield constructs that better approximate the native meniscus while remaining reproducible and processable. To test this hypothesis, several fabrication routes were explored, including extrusion-based 3D printing, injection-based indirect manufacturing, and digital light processing (DLP). Across these approaches, the effects of polymer molar mass, functionality, concentration, and scaffold architecture on swelling behavior, gel fraction, morphology, and compressive mechanical performance were systematically investigated. The results showed that both material composition and scaffold design strongly influenced the final properties of the constructs. Increased polymer concentration and higher functionality generally produced stiffer networks, while architectural parameters such as pore size, strut diameter, and printing pattern significantly affected compressive response. DLP further enabled the fabrication of scaffolds with improved geometric fidelity and reproducibility. In addition, this thesis examined the influence of dehydration and post-processing on scaffold performance. Different drying methods significantly altered scaffold microstructure, swelling capacity, and compressive properties after rehydration, demonstrating that post-processing is not merely a practical handling step but an important parameter in scaffold design. Overall, this work demonstrates that AUP-based hydrogels represent a versatile platform for the development of porous, reproducible, and mechanically tunable scaffolds for meniscus replacement. While the obtained constructs showed promising static mechanical properties, fatigue resistance under prolonged cyclic loading remains a key limitation for future clinical translation. Nevertheless, this thesis provides a strong foundation for the further development of clinically relevant synthetic scaffolds for full meniscus replacement.
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