Experimental study on preparation of coaxial drug-loaded tissue-engineered bone scaffold by 3D printing technology

In order to combine the drug with the tissue-engineered bone scaffold and make the drugs on the scaffolds stable to achieve sustained-release stepwise function, a new method for preparing coaxial drug-loaded tissue engineering bone scaffolds using coaxial three-dimensional printing technology is proposed, in which inner layer material can carry drugs and the outer material can adjust the drug sustained-release rate. The coupling mechanism of both shape control and property control in the process of coaxial three-dimensional printing micro-structural unit is presented. Design-Expert software is introduced for experimental design. The influences of extrusion speed, filling speed, and delamination height on the forming quality are analyzed, and a coaxial gradient composite scaffold model with controllable micro-structure is established. The macro-structure, mechanical properties, in vitro degradation rate, and drug release rate of the scaffolds were analyzed. The experimental results show that the proposed forming technology and process parameter optimization can effectively improve the forming quality of the coaxial scaffold. At the same time, this design of the coaxial structure can effectively slow down the degradation rate of the scaffold and enables stable and long-time drug release. Furthermore, the presented method provides a new technical approach for the further implementation of implantable drug delivery systems for the effective treatment of bone tuberculosis.