• nanocomposite
• ionic-crosslinking
• graphene oxides
• gellan gum
• articular cartilage
• 3D Bio-printing
• PEGDA
• photo-crosslinking

Articular cartilage is a complex multi-layered structure organized into four zones, namely superficial, middle, deep and calcified layers. Zonal organization plays an important role in cartilage structure and function. Its mechanical properties are varying with depth, and the compression modulus of the superficial and deep zone can achieve the value of 0.28 ± 0.16 MPa and 0.73 ± 0.26 MPa, respectively. There exists a need for a new class of scaffolds that may allow for the engineering a new tissue with zonal properties. To address this need, we developed mechanically tunable nanocomposites hydrogel for mimicking compression mechanical properties of the layers of the articular cartilage. Gellan gum (GG)/poly (ethylene glycol) di-acrylate hydrogels (PEGDA) where prepared and its mechanical properties were tuned by changing PEGDA and photoinitiator concentrations. Double crosslinking also has been tested with two UV light duration (5,10) min and ionic crosslinking with magnesium chloride solution. After the target compressive mechanical properties have been reached, nanoparticles have been added to the hydrogels to increase its chondrogenicity.