Multi-material and Multi-dimensional 3D Printing for Biomedical Materials and Devices

Abstract

In recent years, Additive Manufacturing (AM) has evolved into a "multi-x" era, such as multi-part design, multi-material, multi-process, multi-mode, multi-scale, multi-dimension, and multi-function. These emerging new features of AM present both tremendous opportunities and challenges for developing and regulating new and novel biomedical materials and devices. This paper focuses on two aspects, namely multi-material and multi-dimension AM. In multi-material 3D printing, the layering step is the key. Modifying the layering method yet without changing the solidifying or bonding principles governing the AM process can enable and significantly advance multi-material 3D printing. In multi-dimensional 3D printing, typically 4D printing and 5D printing, the meaning of "D" is suggested to refer to space-time dimension rather than the number of degrees of freedom in physical space. It is proposed in this paper that an alternative dimension (or 5D) for future 3D printing processes can be that of scale. Scale here refers the different levels of resolution that are used simultaneously within a print. In such a scale dimension, continuous printing of cross-scale or varied resolution design features in a single build process without affecting the overall printing speed and time would be highly desirable. This is probably the first paper reflecting on multi-material 3D printing from the perspective of layering and on multi-dimensional 3D printing with regard to its future development.

Future trends of additive manufacturing in medical applications: An overview

“…During the development of the bibliographical foundation of the document, using the methodology with the chosen search criteria, it was discovered that some authors had differing opinions on how particular technologies were addressed. In certain documents, terms such as “multi-axis”, “multi-dimensional”, and “multi-material” were used when referring to 4DP, 5DP, and 6DP technologies [207] . It must be clarified that a significant scientific faction adopted the “X” DP terminology.…”

Powder Bed Fusion 3D Printing in Precision Manufacturing for Biomedical Applications: A Comprehensive Review

“…Printing many materials in 3D organ printing poses challenges because of the different properties of the materials. Precision control over materials is necessary for organ printing [231]. Material thermal properties vary, and the combination of multiple materials can result in cracking, porosity, and poor interlayer adhesion [232].…”

3D/4D printed bio-piezoelectric smart scaffolds for next-generation bone tissue engineering

“…Hybrid 3D printing, known as multi-step 3D printing or multi-process 3D printing, is a fresh field of research in which basic 3D printing is enhanced with complementary processes to create objects with multi-material and multifunctionality [139][140][141]. In comparison to a single 3D printing technique, hybrid 3D printing has demonstrated numerous outstanding advantages in developing novel tissue scaffolds: (i) programmable integration of multiple biomaterials, including spatial control of material (cell), geometry, scale, and dimension [142]; (ii) designable couplings of multiple biofunctions such as antibacterial, osteogenic, angiogenic, and anti-tumor [143]; (iii) process flexibility enhancement to eliminating the limitations of a single 3D printing technique while integrating the advantages of traditional manufacturing, such as a subtractive process machine interlocking root structures [144]. (iv) Expanded clinical applications for bone tissue repair, such as holistic osteochondral repair in joints with vastly different mechanical and biological requirements [145].…”