3D printing for regenerative medicine: From bench to bedside

Abstract

Organ shortage is a severe challenge worldwide. Three-dimensional (3D) printing, a rapidly developing engineering and materials science tool, holds considerable promise in generating implantable organ scaffolds that may reduce or eliminate organ shortage. However, translation of 3D printing into clinical therapies has been astonishingly slow and certainly has not matched the pace of technology development. This review outlines challenges and opportunities for the application of 3D printing in tissue and organ regeneration, with emphasis on in vivo applications of 3D-printed scaffolds. Three-dimensional-printed scaffolds for the regeneration of complex tissues and organs, including bone, cartilage, tooth, and skin, serve as prototypes for 3D printing of other tissues and organs such as the liver, kidney, or heart. The aspiration to reduce or eliminate organ shortage appears to hinge on the translation of 3D bioprinting technologies into preclinical studies and clinical trials. The remaining challenges of cell survival, directed differentiation, angiogenesis, and metabolic exchange are far from trial and need to be addressed. Three-dimensional-printed materials will remain a biomaterials and engineering showcase unless applications in preclinical and clinical models are realized. In balance, 3D printing holds considerable promise in regenerative medicine as a unique approach to address organ shortage.

Printing of Three-Dimensional Tissue Analogs for Regenerative Medicine

“…bone morphogenic proteins) in 3-D printed scaffolds, and development of osteoinductive 3-D scaffolds 54 . However, large-size bone defects hardly heal without cell delivery, thus introducing cells within the scaffolds are necessary.…”

“…For this reason, extrusion printing technique is often chosen as a fabrication method. Sintering-based techniques are also popular for scaffolds with even higher mechanical properties 6, 54 . To promote bone formation, Osteoblasts 47, 86, 89 and mesenchymal stem cells (MSCs) 8, 92 can be embedded within the scaffolds during printing procedure or seeded on the scaffold surfaces.…”

“…Collagen I, fibrin, and commercially-available acellular dermal substitute (such as Matriderm) are some examples of popular scaffold materials for skin tissue engineering. Most of skin printing approaches incorporate keratinocytes, fibroblasts, and/or stem cell-derived skin cells as 5, 43, 44, 48, 51, 54, 59, 82 .…”

“…Addressing these complexities requires interdisciplinary approaches that pursue the integration of technologies from the fields of engineering, materials science, biology, chemistry and medicine. For a comprehensive review of 3-D bioprinting technology and issues related to how to integrate all these diverse fields, several excellent review articles have been published recently 1, 54, 63 . This review summarizes the most recent development of 3-D cell printing technologies to construct live tissues and its applications in disease modeling.…”

Direct Writing of Three-Dimensional Macroporous Photonic Crystals on Pressure-Responsive Shape Memory Polymers

“…[1][2][3][4] In 3D printing, successive layers of materials (e.g., polymers, ceramics, and metal alloys) are laid down under computer control through processes like inkjet printing, extrusion, and sintering. Beyond conventional manufacture of macroscopic objects (e.g., customized shoes, automobile parts, and even guns), 3D printing has also been extensively exploited for fabricating microscopic devices with unique optical, electrical, magnetic, and biological properties.…”