Graphene Oxide‐Doped Gellan Gum–PEGDA Bilayered Hydrogel Mimicking the Mechanical and Lubrication Properties of Articular Cartilage

Abstract

Articular cartilage (AC) is a specialized connective tissue able to provide a low‐friction gliding surface supporting shock‐absorption, reducing stresses, and guaranteeing wear‐resistance thanks to its structure and mechanical and lubrication properties. Being an avascular tissue, AC has a limited ability to heal defects. Nowadays, conventional strategies show several limitations, which results in ineffective restoration of chondral defects. Several tissue engineering approaches have been proposed to restore the AC's native properties without reproducing its mechanical and lubrication properties yet. This work reports the fabrication of a bilayered structure made of gellan gum (GG) and poly (ethylene glycol) diacrylate (PEGDA), able to mimic the mechanical and lubrication features of both AC superficial and deep zones. Through appropriate combinations of GG and PEGDA, cartilage Young's modulus is effectively mimicked for both zones. Graphene oxide is used as a dopant agent for the superficial hydrogel layer, demonstrating a lower friction than the nondoped counterpart. The bilayered hydrogel's antiwear properties are confirmed by using a knee simulator, following ISO 14243. Finally, in vitro tests with human chondrocytes confirm the absence of cytotoxicity effects. The results shown in this paper open the way to a multilayered synthetic injectable or surgically implantable filler for restoring AC defects.

Graphene Oxide and Reduced Graphene Oxide Nanoflakes Coated with Glycol Chitosan, Propylene Glycol Alginate, and Polydopamine: Characterization and Cytotoxicity in Human Chondrocytes

“…Both materials are generally featured by a nanometric thickness and a large lateral dimension, from hundreds of nanometers up to tens of microns, making them versatile for several applications. For example, GO and rGO have been used as electrical dopant agents in conductive composite materials [ 5 , 6 ], for mechanical reinforcement of polymeric matrices [ 7 ], or as lubricant agents to improve the wear of scaffolds to be used as substitutes for load-bearing joints [ 8 , 9 ].…”

An Engineered Protein Adhesive with Properties of Tissue Integration and Controlled Release for Efficient Cartilage Repair

“…Articular cartilage plays a crucial role in load‐bearing and friction reduction during the movement of the synovial joint. [ 1 ] Its avascular and aneural nature, high water content, high level of organization, and biomechanical properties make it a unique structure in the human body. [ 2 ] Damage to the cartilage may lead to joint dysfunction and even disability.…”

Biological Characterization of Polymeric Matrix and Graphene Oxide Biocomposites Filaments for Biomedical Implant Applications: A Preliminary Report

“…New efforts applied to tissue engineering (TE) aim to replace or at least repair organs and tissues through transplants (allo, auto and xenotransplantation) [ 1 , 2 , 3 ]. Among the TE developed approaches, the use of nanomaterials has shown promising results to solve challenges related to surgical clinics [ 4 ].…”

“…Recently, in order to improve these problems, carbon nanostructures such as graphene (Gr) and graphene oxide (GO) are providing new perspectives for TE. These can be applied in drugs and genes delivery of, as well as in the articular repair and bone defects [ 3 , 7 , 8 , 9 , 10 ] due to their physical characteristics such as mechanical strength, flexibility, elasticity [ 11 ], low density [ 12 ], structural support, self-lubricating properties and anti-wear due to its laminar structure which supports in the surface lubrication. Furthermore, these can be applied to mediate cell proliferation, differentiation and migration and improve the bone repair effect [ 7 , 13 , 14 , 15 , 16 ].…”

“…On the other hand, GO is a graphene-derived nanosheet structured by epoxy, hydroxyl and carboxyl groups on its surface that make it more hydrophilic. These groups also promote biological interactions with nanosheets allowing their use for neural regeneration in tissue engineering [ 22 ] and providing a compatible environment for chondrogenic cell proliferation [ 3 ].…”