Fabrication of dense anisotropic collagen scaffolds using biaxial compression

Abstract

In vitro studies of cell-matrix interactions and the engineering of replacement materials for collagenous connective tissues require biocompatible scaffolds that replicate the high collagen density (15-25%/wt), aligned fibrillar organization, and anisotropic mechanical properties of native tissues. However, methods for creating scaffolds with these characteristics are currently lacking. We developed a new apparatus and method to create high density, aligned, and porous collagen scaffolds using a biaxial compression with porogens technique. These scaffolds have a highly directional structure and mechanical properties, with the tensile strength and modulus up to 100 times greater in the direction of alignment. We also demonstrated that the scaffolds are a suitable material for cell culture, promoting cell adhesion, viability, and an aligned cell morphology comparable to the cell morphology observed in native aligned tissues.

Surgical and tissue engineering strategies for articular cartilage and meniscus repair

“…Scaffold-free approaches have also been used to generate zonal tissue and anisotropy; for example, anisotropic menisci with zonal variations have been produced using the self-assembling process 107 . These studies [104][105][106][107] suggest that recapitulating zonal and anisotropic properties of cartilage and menisci might be necessary to impart native functional properties to a tissue-engineered product.…”

“…Advances in scaffold-based and scaffold-free approaches have also focused on the recapitulation of native tissue architecture [104][105][106][107] . For example, stiffness gradient hydrogels (0.005-0.06 MPa) derived from poly(ethylene glycol) and chondroitin sulfate yield constructs with stiffness-dependent glycosaminoglycan gradients that mimic the glycosaminoglycan gradient found in articular cartilage between the superficial and deep zones 104 .…”

“…In another study, bi-layered poly(ε-caprolactone) scaffolds with porous layers and aligned fibrous layers supported the development of zonal arrangement of engineered cartilage 105 . Collagen density and the alignment of porous collagen scaffolds can also be tailored via biaxial compression 106 , which might be useful for engineering anisotropy in the meniscus. Scaffold-free approaches have also been used to generate zonal tissue and anisotropy; for example, anisotropic menisci with zonal variations have been produced using the self-assembling process 107 .…”

Driving Hierarchical Collagen Fiber Formation for Functional Tendon, Ligament, and Meniscus Replacement

“…In an effort to engineer tissues with higher concentrations of collagen, plastic compression of collagen gels has been investigated. In these systems, low density collagen gels are compressed, forcing water out and producing densified gels [34][35][36][37]. While these culture systems result in collagen densities similar to native tissue (100-250 mg/ml) and develop larger fiber-like morphologies, they lack the fibril level organization and do not replicate native tissue hierarchy [34][35][36][37].…”

Genipin‐crosslinked decellularized annulus fibrosus hydrogels induces tissue‐specific differentiation of bone mesenchymal stem cells and intervertebral disc regeneration

“…As it has long been identified that cellular physiology of disc cells is largely affected by the mechanical environment in AF tissues (Vergroesen et al, 2015), many engineered scaffolds have been fabricated for AF biomechanical restoration and pain relief, including natural scaffolds (Zitnay et al, 2018), synthetic polymers (Christiani, Baroncini, Stanzione, & Vernengo, 2019), and their combination (Yang et al, 2017). Among various types of scaffolds, in situ tissue-derived biomaterials, which closely mimic the prominent features of the native tissue microarchitecture and support an appropriate, tissue-specific cell phenotype, have their innate advantages in native tissue repair (Bejleri & Davis, 2019).…”