Triphasic 3D In Vitro Model of Bone-Tendon-Muscle Interfaces to Study Their Regeneration

Abstract

The transition areas between different tissues, known as tissue interfaces, have limited ability to regenerate after damage, which can lead to incomplete healing. Previous studies focussed on single interfaces, most commonly bone-tendon and bone-cartilage interfaces. Herein, we develop a 3D in vitro model to study the regeneration of the bone-tendon-muscle interface. The 3D model was prepared from collagen and agarose, with different concentrations of hydroxyapatite to graduate the tissues from bones to muscles, resulting in a stiffness gradient. This graduated structure was fabricated using indirect 3D printing to provide biologically relevant surface topographies. MG-63, human dermal fibroblasts, and Sket.4U cells were found suitable cell models for bones, tendons, and muscles, respectively. The biphasic and triphasic hydrogels composing the 3D model were shown to be suitable for cell growth. Cells were co-cultured on the 3D model for over 21 days before assessing cell proliferation, metabolic activity, viability, cytotoxicity, tissue-specific markers, and matrix deposition to determine interface formations. The studies were conducted in a newly developed growth chamber that allowed cell communication while the cell culture media was compartmentalised. The 3D model promoted cell viability, tissue-specific marker expression, and new matrix deposition over 21 days, thereby showing promise for the development of new interfaces.

Multimaterial and multiscale scaffold for engineering enthesis organ

“…The other parameters are comparable with data reported in the literature regarding electrospun PLGA mats with aligned fibers [ 46 , 47 ] . When comparing data with the literature, the enthesis scaffolds show improved mechanical properties: Balestri et al [ 48 ] fabricated an in vitro model of a bone–tendon–muscle interface that recorded an elastic modulus of hundreds of kPa; Criscenti et al [ 12 ] provided an enthesis scaffold fabricated by electrospun PLGA onto PCL grids registering Young’s modulus as less than 100 MPa.…”

Snail Mucus-Enhanced Adhesion of Human Chondrocytes on 3D Porous Agarose Scaffolds

“…First, 1.5 mg/mL SMu solution in 0.5% (v/v) acetic acid was prepared and prewarmed at 45 °C. The prewarmed SMu was then aliquoted in different volumes (25,50, and 75% (v/v)) with respect to the agarose solution, as indicated in Table 1. The agarose solution was prepared accordingly and allowed to cool until 45 °C, and the prewarmed SMu was then added to the agarose solution and stirred for 30 min.…”

“…Although agarose hydrogels exhibit desirable properties for tissue engineering applications, especially cartilage regeneration, the major drawback of this polymer is the lack of cell adhesion properties . To address this limitation, researchers chemically modify agarose or combine it with bioactive polymers such as collagen, , chitosan, ,, and gelatin. , For example, Been et al designed a composite agarose and soluble eggshell (as a collagen) scaffold for cartilage regeneration. The composite scaffold reduced inflammatory response, promoted cell proliferation, and increased ECM deposition, thereby promoting cartilage regeneration .…”