Strategies for Replicating Anatomical Cartilaginous Tissue Gradient in Engineered Intervertebral Disc

Abstract

A critical challenge in fabricating a load bearing tissue, such as an intervertebral disc, is to simulate cellular and matrix alignment and anisotropy, as well as a specific biochemical gradient. Towards this goal, multilamellar silk fibroin scaffolds having criss-cross fibrous orientation were developed, where silk fibers in inner layers were crosslinked with bioactive molecule chondroitin sulfate. Upon culturing goat articular chondrocytes under static and dynamic conditions, lamellar scaffold architecture guided alignment of cells and the newly synthesized extracellular matrix (ECM) along the silk fibers. The dynamic culture conditions further improved the cellular metabolic rate and ECM production. Further the synergistic effect of chemical composition of scaffold and hydrodynamic environment of bioreactor contributed in developing a tissue gradient within the constructs, with an inner region rich in collagen II, glycosaminoglycan (GAG), and stiffer in compression, whereas an outer region rich in collagen I and stiffer in tension. Therefore, a unique combination of chemical and physical parameters of engineered constructs and dynamic culture conditions provides a promising starting point to further improve the system towards replicating the anatomical structure, composition gradient, and function of intervertebral disc tissue.

Role of chondroitin sulphate tethered silk scaffold in cartilaginous disc tissue regeneration

“…Articular chondrocytes were isolated from the goat cartilage by enzymatic treatment with 0.1% w/v type II collagenase (Gibco) for 16 h at 37 °C [2]. Once isolated the cells were resuspended in a culture medium containing Dulbecco's modified Eagle medium (Cellclone) with 10% fetal bovine serum (Biological Industries), 100 U ml −1 penicillin-streptomycin, 2.5 μg ml −1 gentamycin and 5 μg ml −1 amphotericin, 5 ng ml −1 fibroblast growth factor-2 (FGF-2) (Millipore) and 1 ng ml −1 transforming growth factor β1 (TGFβ1) (Millipore).…”

Extrusion-based 3D printing of poly(propylene fumarate) scaffolds with hydroxyapatite gradients

“…Recent work in the tissue engineering community has sought to recapitulate the complexities of the osteochondral interface by fabricating scaffolds with gradients of extracellular matrix (ECM) [2], bioactive molecules [3], and pore size gradients [4, 5]. Biologically, calcium phosphate concentrations gradually increase from the uncalcified region of cartilage to underlying region of subchondral bone [1].…”

Preparation and properties of dopamine‐modified alginate/chitosan–hydroxyapatite scaffolds with gradient structure for bone tissue engineering

“…21 Therefore, it is of significance in the development of biomaterials for osteochondral application to adequately mimic the gradient structure of natural osteochondral tissue. This gradient structure of bone tissue is of critical importance to ensure the biological tissue work properly.…”

“…This gradient structure of bone tissue is of critical importance to ensure the biological tissue work properly. 21 Therefore, it is of significance in the development of biomaterials for osteochondral application to adequately mimic the gradient structure of natural osteochondral tissue. 22 Some methods have been developed to prepare the gradient scaffolds, including thermally induced phase separation and porogen leaching, electrospinning, rapid prototyping technology, freeze-drying, and so on.…”