Engineering articular cartilage : Biomimicking materials for cartilage tissue substitution

Abstract

Articular cartilage can be damaged due to injury or disease. It has limited regenerative capacity and current treatment methods still face challenges, including immune responses, difficulties in repairing large-area defects, and issues related to tissue integration. This thesis focuses on the new strategies of articular cartilage, specifically cartilage substitution. In this work, the material options suitable for cartilage substitution are presented, with particular attention to their mechanical properties and biocompatibility, in order to identify substitutes that can mimic native cartilage as closely as possible. Also, the fabrication and processing of these materials are discussed.

Articular cartilage is divided into five distinct zones: superficial zone, middle zone, deep zone, calcified cartilage, and subchondral bone. The composition, biomechanics, and cell biology of these zones are described in detail in this thesis. Non-biodegradable materials are assigned to each cartilage zone with soft tissue, and biodegradable materials are assigned to the subchondral bone region, resulting in a multilayered biomaterial with potential for cartilage substitution. To illustrate such a structure, a bilayered substitute was also produced and subjected to compression and dissolution tests. The layered material consisted of a bioactive glass scaffold with a GelMA hydrogel layer on top.

The results of the experiments showed that the hydrogel layer cast on top of the bioactive glass remained attached to the glass layer for three days in solution, indicating that such a structure would remain intact in a physical environment. From dissolution tests, the mass loss and water absorption were determined, and from compression tests, the Young’s modulus and compressive strength of the substitute were determined.