Advanced optical methods and materials for fabricating 3D tissue scaffolds

Three-dimensional(3D)printing,also known as additive manufacturing(AM),has undergone a phase of rapid development in the fabrication of customizable and high-precision parts.Thanks to the advancements in 3D printing technologies,it is now a reality to print cells,growth factors,and various biocompatible materials altogether into arbitrarily complex 3D scaffolds with high degree of structural and functional similarities to the native tissue environment.Additionally,with overpowering advantages in molding efficiency,resolution,and a wide selection of applicable materials,optical 3D printing methods have undoubtedly become the most suitable approach for scaffold fabrication in tissue engineering(TE).In this paper,we first provide a comprehensive and up-to-date review of current optical 3D printing methods for scaffold fabrication,including traditional extrusion-based processes,selective laser sintering,stereolithography,and two-photon polymerization etc.Specifically,we review the optical design,materials,and representative applications,followed by fabrication performance comparison.Important metrics include fabrication precision,rate,materials,and application scenarios.Finally,we summarize and compare the advantages and disadvantages of each technique to guide readers in the optics and TE communities to select the most fitting printing approach under different application scenarios.