Trends in 3D Printing Processes for Biomedical Field: Opportunities and Challenges

Abstract

Keywords: Additive manufacturing; Bioinks; Biomaterials; Bioprinting; Machine learning; Medicine; Polymer.

Fig. 1

Schematic illustration showing the AM process flow and evolution over the years

Fig. 2

Schematic illustration showing the main differences between 3D (bio)printing and 4D (bio)printing

Fig. 3

3D bioplotting of alginate hydrogels: a cultivated Schwann cells mixed with alginate hydrogel and then bioplotted, b cell-incorporated alginate scaffold and staining result showing one strand, and c poor printability of 0.5% alginate printed with a 100-µm needle and staining result of cell-incorporated gel [50]

Fig. 4

Stent configurations: a Stent cell geometries employed; b Stent material/layers used [88]

Fig. 5

3D printed objects fabricated using different AM techniques: a PCL/PEG polyblend scaffold for bone regeneration; [94] b PCL, PVAc and hydroxyapatite composite porous scaffolds employing bone regeneration; [96] c 3D printed nose based on a alginate–chitosan complex hydrogel; [59] d native anatomic and axisymmetric aortic valve geometries printed with PEG-diacrylate hydrogels; [145] e various 3D anatomical geometries based on PEG–alginate–nanoclay hydrogels; [146] f PEG hydrogel microspheres as bilding blocks for 3D printed scaffolds; [115] g vascular structures based on alginate; [147] h 3D-printed artificial trachea scaffolds based on PCL; [148] i 3D printed anterior cruciate ligament screw from PLA-magnesium-α-tocopherol; [149] j 3D scanned models of wrist splints based on PLA; [150]. Reproduced with permission

Fig. 6

Dual-shape change tubes. a Schematic of the basic anatomy of the coral polyp; the image was created based on encyclopedic depictions of the polyp.50 b, c CAD model and image of a 3D printed and photocured tube with cylindrical base and three fingers. d–g Optical snapshots of shape change of the tube at different temperatures. The tube was suspended over a part placed in a tank. When water was added to the tank, the tube shows uniaxial elongation and gripping of the part. Upon heating to 50 °C, the tube shortened and the fingers opened to release the part back to the bottom of the tank. Scale bars are 1 cm [159]

Fig. 7

Examples of the fabricated self-folding tubes (from right to left): schematic illustrations and representative microscope images of single tubes with/without printed cells formed through the described 4D biofabrication process; photograph of a glass vial containing a large number of self-folded tubes, indicating on the possibility of their large-scale production [7]

Fig. 8

The core concepts of AM and ML (adapted from Felix W. Baumann et al. [211])

Fig. 9

The relationship between ML and AM processes. (adapted from Felix W. Baumann et al. [211])