Anatomical meniscus construct with zone specific biochemical composition and structural organization

Abstract

A PCL/hydrogel construct that would mimic the structural organization, biochemistry and anatomy of meniscus was engineered. The compressive (380 ± 40 kPa) and tensile modulus (18.2 ± 0.9 MPa) of the PCL scaffolds were increased significantly when constructs were printed with a shifted design and circumferential strands mimicking the collagen organization in native tissue (p<0.05). Presence of circumferentially aligned PCL strands also led to elongation and alignment of the human fibrochondrocytes. Gene expression of the cells in agarose (Ag), gelatin methacrylate (GelMA), and GelMA-Ag hydrogels was significantly higher than that of cells on the PCL scaffolds after a 21-day culture. GelMA exhibited the highest level of collagen type I (COL1A2) mRNA expression, while GelMA-Ag exhibited the highest level of aggrecan (AGG) expression (p<0.001, compared to PCL). GelMA and GelMA-Ag exhibited a high level of collagen type II (COL2A1) expression (p<0.05, compared to PCL). Anatomical scaffolds with circumferential PCL strands were impregnated with cell-loaded GelMA in the periphery and GelMA-Ag in the inner region. GelMA and GelMA-Ag hydrogels enhanced the production of COL 1 and COL 2 proteins after a 6-week culture (p<0.05). COL 1 expression increased gradually towards the outer periphery, while COL 2 expression decreased. We were thus able to engineer an anatomical meniscus with a cartilage-like inner region and fibrocartilage-like outer region.

One‐Step Photoactivation of a Dual‐Functionalized Bioink as Cell Carrier and Cartilage‐Binding Glue for Chondral Regeneration

“…While the mechanical properties of both gels are relatively low for applications in large tissue defects subjected to continuous mechanical loads, several reinforcing strategies based on the combination or coprinting with stiff thermoplastic support scaffolds have already been reported in the literature to address this common limitation for bioinks. [ 51 – 54 ] Further analysis into the gene expression over the 28 day culture period showed that both collagen type II and type I expression was upregulated in the GelMA and GelMA-Tyr hydrogels ( Figure 3D,E ). It was also observed that the collagen type II expression is significantly higher in the GelMA-Tyr samples (0.8-fold) after 28 days as compared to GelMA (0.3-fold).…”

Mesenchymal stem cells loaded on 3D-printed gradient poly(ε-caprolactone)/methacrylated alginate composite scaffolds for cartilage tissue engineering

“…Collagen II is mainly produced by chondrocytes, aggrecan is mainly distributed in the ECM, and SOX9 is the earliest markers for MSC differentiation into chondrocytes [ 44 ]. Collagen X is commonly associated with chondrocyte hypertrophy and is expressed in MSCs that undergo chondrogenesis after 21 days of culture [ 45 ]. Moreover, the PMA-gradient scaffold exhibited significantly higher expression levels of collagen II, collagen X and SOX9 in comparison to the other networks, and the expression of aggrecan was slightly lower than DL-PMA networks.…”

Meniscal Regenerative Scaffolds Based on Biopolymers and Polymers: Recent Status and Applications

“…A mixture of agarose and GelMA hydrogel was found to induce aggrecan expression and produce a high ratio of collagen type II/collagen type I in human fibrochondrocyte-hydrogel constructs. Moreover, the construct consisting of the blended hydrogel combined with the PCL scaffold perfectly mimicked the natural meniscal interior region (Bahcecioglu et al, 2019). Hyaluronic acid (HA) is a natural hydrophilic GAG that is found in connective tissue, such as cartilage ECM, and is especially abundant in synovial fluid (Zamboni et al, 2018;Shah et al, 2019).…”

“…Thus, gelatin modified with GelMA has also been studied as a polymeric meniscal scaffold. A study showed that GelMA in the construct significantly enhanced the adhesion of chondrocytes and the secretion of type II collagen ( Bahcecioglu et al, 2019 , 2019a ).…”

“…Among natural polymers, agarose represents a natural and neutral, transparent polysaccharide that has excellent water solubility, biocompatibility, tunable mechanical properties and controllable self-gelation properties ( Salati et al, 2020a ) and plays an important role in the inner region in meniscal tissue repair ( Bahcecioglu et al, 2019 , 2019a , b ). Experiments have shown attractive GAG expression in the agarose-impregnated interior meniscal region.…”