3D‐Printed Reinforcement Scaffolds with Targeted Biodegradation Properties for the Tissue Engineering of Articular Cartilage

Abstract

Achieving regeneration of articular cartilage is challenging due to the low healing capacity of the tissue. Appropriate selection of cell source, hydrogel, and scaffold materials are critical to obtain good integration and long-term stability of implants in native tissues. Specifically, biomechanical stability and in vivo integration can be improved if the rate of degradation of the scaffold material matches the stiffening of the sample by extracellular matrix secretion of the encapsulated cells. To this end, a novel 3D-printed lactide copolymer is presented as a reinforcement scaffold for an enzymatically crosslinked hyaluronic acid hydrogel. In this system, the biodegradable properties of the reinforced scaffold are matched to the matrix deposition of articular chondrocytes embedded in the hydrogel. The lactide reinforcement provides stability to the soft hydrogel in the early stages, allowing the composite to be directly implanted in vivo with no need for a preculture period. Compared to pure cellular hydrogels, maturation and matrix secretion remain unaffected by the reinforced scaffold. Furthermore, excellent biocompatibility and production of glycosaminoglycans and collagens are observed at all timepoints. Finally, in vivo subcutaneous implantation in nude mice shows cartilage-like tissue maturation, indicating the possibility for the use of these composite materials in one-step surgical procedures.

Structural Strength Analyses for Low Brass Filler Biomaterial with Anti-Trauma Effects in Articular Cartilage Scaffold Design

“…Traditionally, tensile strength was the main parameter used to measure the requisite strength for vascular supportive [47] structures for scaffold designs [18], as shown in Table 1. The tensile strengths of titanium dioxide and low brass were more than enough to maintain the structure's support because they were four-times higher than tendon and ligament tissues.…”

“…This articular cartilage scaffold was a supportive structure [16,17] requiring a structural integrity [18] feature in the biomimetic design of the tissue engineering environment [19,20]. As shown in Table 1, both titanium dioxide and the low brass filler biomaterials had the requisite tensile strengths to maintain the structural integrity of this supportive structure.…”

“…Finding a biomaterial with better mechanical properties does not seem to be a better choice. Therefore, the scaffold is a supportive structure [16,17] that has become a popular option to improve structural strength and structural integrity [18]. This biomimetic tissue engineering environment [19,20] was invented to treat articular cartilage tissue [21], microfracture [4,22], and osteochondral defects [23,24].…”

“…Firstly, the biomaterials must provide the requisite mechanical strength for the scaffold. Secondly, the flexural strength was required to comply with the structural integrity requirement [16,26,37] for the scaffold's design criteria [18,27]. Lastly, FESEM and XRD were used to study the physical characteristics of the microstructure.…”

3D printed gelatin/decellularized bone composite scaffolds for bone tissue engineering: Fabrication, characterization and cytocompatibility study

“…Hydrogels are widely used as biomaterial inks in 3D printing techniques since their mechanically supportive microenvironment, controllable physical or chemical properties, as well as cellular compatibility allow their use in tissue engineering applications [ 4 , 5 ]. Moreover, hydrogels can mimic the extracellular matrix (ECM) of many tissues with their porous network and provide a suitable microenvironment for cells to migrate and proliferate [ 6 , 7 ]. There are various techniques to fabricate porous hydrogels such as 3D printing [ 8 , 9 ], freeze-drying [ [10] , [11] , [12] ], or porogen-based methods [ 13 , 14 ].…”