A review on additive manufacturing of lattice structures in tissue engineering

Lattice structures are composed of interconnected porous unit cells that are arranged in a periodic and regular fashion. Their light wight and high specific strength alongside many other superior mechanical properties, have made them an excellent candidate for tissue engineering applications. In tissue engineering, porous structures (scaffolds) are employed for regeneration of living and healthy tissues and organs. Via their specific architecture, lattice structures can provide a proper environment for cells to attach to and colonize. Additive Manufacturing (AM) offers great flexibility in fabrication of lattice structures for tissue engineering. AM can apply complex design of unit cells and duplication patterns, to generate high quality lattice structures with good accuracy. In addition, biocompatibility and biodegradability of lattice structures that are main concerns in tissue engineering, can be addressed with a wide range of material choices in different AM methods. In this review, additive manufacturing of lattice structures in tissue engineering is discussed, with a focus on materials and AM methods that have been studied in the existing literature. Furthermore, various designs of unit cells in the AM of lattice structures, the effect of AM process parameters, challenges and future of this field are reviewed.