• Smart Materials for Dynamic Bone Healing: The Future of 4D Printing in Tissue Engineering and Regenerative Medicine
  • zahra amiri,1 Azizeh Rahmani Del Bakhshayesh,2 Ahmad Mehdipour,3,* sara bazdar,4
    1. Department of Tissue Engineering, Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences
    2. Department of Tissue Engineering, Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences
    3. Department of Tissue Engineering, Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences
    4. Department of Tissue Engineering, Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences


  • Introduction: Bone tissue is one of the largest tissues in the body. Sometimes unexpected events like accidents, trauma, and surgeries lead to some deformities in bone tissue. In large-scale defects, there are some challenges for bone healing, so bone tissue engineering and using synthetic or natural biomaterials are used to overcome these challenges. 3d and 4d printing are the newest types of scaffold fabrication in tissue engineering. In 4D printing, polymers stimulate under different conditions like pH, water, temperature and leading to visualize some shape changes in printed scaffolds.
  • Methods: Polymers like polycaprolactone(PCL), poly lactic acid (PLA), polyurethane(PU) and propylene glycol diacetate (PGDA) are categorized as shape memory polymers. The composition of these polymers with other polymers or hydrogel can provide a shape memory effect for materials.
  • Results: In 4D printing for the spine, the scaffold is printed in a flat space and after stimulation transforms into a curved shape. To achieve this goal, Using A collagen hydroxyapatite scaffold containing microchannels can be a suitable choice to print for bone graft that can promote new bone formation in spinal fusion. In addition we can use PLA/Fe3O4 for printing to achieve shape memory effects for spinal bones that can be stimulated under hot water and magnetic fields. Also we can suggest using 3d printed polylactide-co-trimethylene carbonate (PLMC) scaffolds contain polydopamine nanoparticles for bone tissue engineering that can demonstrate shape recovery properties under NIR irradiation along with osteogenic potential. Pla in combination with hydroxyapatite also can be used to construct the porous bone scaffold with shape memory activity.
  • Conclusion: In conclusion, it seems that using these dynamic scaffolds with smart properties or shape memory activity may be useful for bone tissue engineering to transform into a defect site that leads to better healing in bone tissue deformities. This marks a significant advancement in regenerative medicine.
  • Keywords: tissue engineering- bone tissue - 4d printing- bone regeneration