A 3D bioprinted bone structure with radial porosity gradient using PCL and alginate bioinks

IntroductionBone tissue engineering is still facing various challenges. Utilizing three-dimensional scaffolds mimicking bone structure with interconnected pores containing bone inducers may overcome some of the constraints.MethodsIn this study, a 3D printed scaffold with radial gradient porosity has been fabricated as a bone tissue scaffold using a bioprinter, called PioneerX4. PioneerX4 is a home-made 3D bioprinting machine that builds up 3D constructs by coordinating the motion of a print module. This device is able to print up to 4 different bioinks in each station. A novel strategy to enhance regional cell differentiation is to design and mimic gradient pore size mimicking real bone structure. Here, a combination of PCL is used as structural material and as a bioink, alginate is printed between them. The diameter of PCL and alginate strands varies in the range of 285 μm and 432 μm which proves enough print accuracy. The scaffold consists of three regional parts distinguished by different porosities including 66.8%, 58.8%, and 25.9% from the inner part to the outer, respectively.ResultsThe compressive modulus of the PCL printed scaffold is about 19.2±2.2 Mpa. Nano Hydroxyapatite was synthesized using conventional chemical wet method and used as a carriers for controlled releasing of dexamethasone. It is showed that about 90% of the total drug released in the first week

Keywords:

Bioprinting , Bioink , Bone tissue engineering , Radial porosity gradient