3D printing in cell culture systems and medical applications

Abstract

3D printing plays an important role in various biomedical research applications including, but not limited to, culture systems and implantable devices. In this review, we discuss recent development in the applications of 3D printing technologies for clinically motivated research, particularly focusing on the fabrication of constructs subsequently incorporated with cells. Applications of this technology include pharmaceutical delivery, bioreactor culture platforms, acellular scaffolds, imaging modalities, and organ-on-a chip systems. Emphasis is placed on technological developments not possible without 3D printing technologies: where traditional manufacturing approaches would be cumbersome to demonstrate research objectives. The clinical applications of 3D printing are rapidly moving from the research to production phases and will certainly continue to grow, with ever increasing numbers of therapies becoming commercialized. The work discussed here holds promise for various applications in structural improvements, drug delivery, and physiology research.

FIG. 1.

Application of 3D printing for the fabrication of bioreactor culture platforms, tissue/disease model developments, and implants. (a) A 3D-printed miniaturized, modular spinning bioreactor for culture and development of brain organoids from iPSCs (top picture). Further application of this platform includes the study of organoid exposure to Zika virus (ZIKV) (bottom), and as a testing platform for potential ZIKV antiviral drugs (left). Adapted with permission from Qian et al., Cell 165, 1238 (2016). Copyright 2016 Elsevier. (b) 3D printing of tough, elastic poly(ethylene glycol) (PEG)-alginate-nanoclay hydrogels for reconstruction of living tissues with high fracture toughness. (i) A hydrogel mesh hosting human embryonic kidney (HEK) cells, showing high viability (green cells). (ii) and (iii) Shapes of printed objects were almost completely recovered following stretching (ii) and compressive strain (iii). Adapted with permission from Hong et al., Adv. Mater. 27, 4034 (2015). Copyright 2015 John Wiley and Sons. (c) A dual-chamber fluidic bioreactor setup as a model of the interactions between cartilage and the subchondral bone. (i) The geometry of each construct allows the chondral and osseous sides to be exposed exclusively to chondrogenic and osteogenic medium, respectively. (ii) An assembly of a bioreactor can accommodate multiple constructs placed in the custom 3D-printed microfluidic plate. Adapted with permission from Lin et al., Mol. Pharm. 11, 2203 (2014). Copyright 2014 American Chemical Society. (d) 3D printing of anterior cruciate ligament surgical implant in a rabbit model. The printed porous PLA scaffolds loaded with MSCs suspended in hydrogel shows significant bone ingrowth and bone-graft interface formation within the bone tunnel in vivo after 4 and 12 weeks in the rabbit models. Adapted from Ref. .

FIG. 2.

3D-printing applications in microfluidics, organs-on-chips systems, and cellular imaging. (a) 3D-printed microfluidic device for the production of hydrogel microcapsules for neuronal stem cell culture. (i) 3D-printed co-extrusion microdevice; scale bar = 5 mm. (ii) Zoomed-in view of the co-extrusion device; scale bar = 500 μm. (iii) Diagram of the co-extrusion setup. Blue: alginate solution, green: intermediate solution, orange: cell suspension, and (iv) immunostaining of a fixed neuronal capsule after 13 days in culture: 4′,6-diamidino-2-phenylindole (DAPI)/nuclei (top) and tubulin subunit beta3 staining (bottom), indicating mature neurites. Scale bar = 50 μm. Adapted with permission from Alessandri et al., Lab Chip 16, 1593 (2016). Copyright 2016 The Royal Society of Chemistry. (b) A 3D-printed microfluidic device as a model of the neuroprotective blood-brain barrier (BBB)-on-a-Chip. (i) Schematic of the fluidic platform, (ii) the assembled device, with red dye for fluid visualization, (iii) schematic of the cross-section of the neuronal chamber, containing co-culture of brain microvascular endothelial cells (BMECs) and rat primary astrocytes, and (iv) immunostaining of claudin-5 and ZO-1 expression in BMECs in the chamber, demonstrating well-organized tight junctions that restrict paracellular transport across the BBB. Scale bar = 50 μm. Adapted with permission from Wang et al., Biotechnol. Bioeng. 114, 184 (2017). Copyright 2016 John Wiley and Sons.