Table 3 Bioprinting used to assemble building blocks
From: Utilizing bioprinting to engineer spatially organized tissues from the bottom-up
Bioprinting technique | Printing mechanism | Bioinks | Building blocks | Cell viability (optimal condition) | Printing resolution | References |
|---|---|---|---|---|---|---|
Inkjet bioprinting | Valve-based printing approach | 1.5% (w/v) alginate hydrogel containing hiPSC or hESCs-derived HLCs | Droplets for liver tissues | Around 55% for 23 days | 100 μm | [64] |
Micro-droplet jetting including microfluidic chips | 20% (w/v) gelatin hydrogel containing single human breast cancer cell or HUVEC | Droplets for cancer disease models | 87% after 7 days | 10 μm, 0.1nL | ||
Oil-immersed nozzle printer into a lipid-in-oil bath | 8:1 (v:v) mixture of 15 mg/ml ULGT-agarose to Fmoc-dipeptide solution containing HEKs or oMSCs | Droplets for cartilage-like tissues | 91% after printing | < 200 μm, 1nL | [66] | |
Ejection within a gentle acoustic field | 0.5 wt% agarose hydrogel containing mESC, RAJI, HL-1, 3T3 or AML-12 | Droplets encapsulating single cell | > 89.8% after printing | around 37 μm | [67] | |
Extrusion-based bioprinting | Extrude with gel-loaded syringes on the heated stage | 13 wt% F127 and 6%wt alginate hybrid gel containing hMSCs | Filaments for cartilage or bone tissues | Around 83% after 7 days | 400 μm | [68] |
Extrude layer-by-layer and dual-crosslink | 5-20 wt% methacrylated Ad-HA and CD-HA | Filaments for guiding cell growth | – | 100–500 μm (adjustable) | [69] | |
Freeform reversible embedding of soft hydrogels | 17.5 wt% PEG-αMA hydrogel containing HPAAFs | Filaments for PAH research models | Around 60% after 21 days (300 μm) | 300 μm or 500 μm | [70] | |
Extrude into perfusable silicone chips | 10 mg/mL fibrinogen, 7.5 wt% gelatin, 1 wt% transglutaminase containing hMSCs and hNDFs | Filaments for vasculature | 90% after printing | 200 μm | [71] | |
Temperature-controlled extrusion and post-printing crosslinking | 5%/7.5%/10% (w/v) gelatin, 1% (w/v) alginate containing ESCs | Filaments for cell viability test |  > 90% after printing | 150 μm | [72] | |
Extrude through a printhead with seven branches | 5 wt% GelMA and 1 wt% alginate containing HDFs, HepG2, hMSCs or HUVECs | Filaments for gradient structures | Around 80% after 7 days | 100–200 μm | [73] | |
Extrude through coaxial nozzles with two inlets | 1% (w/v) alginate and 1% (w/v) gelatin containing Min6 and HepG2 | Filaments for perfusable network | Around 80% after 7 days | 50 μm | [74] | |
Compact bioink in syringe reservoir and extrude through nozzle | 10% (w/v) collagen containing cardiac spheroids of hiPSC-CM and hDNFs | Elongated microtissues for cardiac tissues | Around 90% after 7 days | 600 μm | [22] | |
Light projection bioprinting | Photo-crosslinking of methacrylate via image projection | 20 wt% PEGDA containing HUVECs or fibrin gel containing hepatocytes | Vascularized alveolar or hepatic units | – | 5pL | [4] |
|  | 2.5% (w/v) GelMA and 1% (w/v) GMHA containing hiPSC-induced HLCs | Hepatic models | 65% after 7 days | < 200 μm | [16] | |
|  | 10% (w/v) GelMA containing fibroblasts | Customized shape and size microgel |  > 90% after 48 h | 10 μm | [43] | |
|  | 10% (w/v) GelMA and 10% (w/v) cartilage microtissues containing chondrocytes | Cartilage microtissues |  > 90% after 20 days | 200 μm | [57] | |
|  | 2.5% (w/v) GelMA, 1% (w/v) HA containing HUVECs and fibroblasts | Vascularized tissues at microscale | > 80% after 7 days | 20 μm | [75] | |
Photo-crosslinking of norbornene via image projection | 3–9 wt% PEG8NB along with PEG4SH | Micro scaffolds for cell culture | – | 50 μm | [76] |