Table 3.
Summary of the Key Properties of Natural and Synthetic Polymers.
| Polymer | Gelation Mechanism | Printing Method | Printing Concentration (w/v) | Cell Viability Rate (%) | Application | Ref. |
|---|---|---|---|---|---|---|
| Natural | ||||||
| Collagen Type I | Self-assembly neutralization in acid medium + thermal gelation (37 °C), photopolymerization, chemical modification |
Inkjet, extrusion |
35 mg/mL | High | Cardiovascular tissue [4], Skin [49], cartilage [50], bone [51], liver [52], nerve regeneration model [53], cornea [54]. |
4 |
| Fibrin | Enzymatic thrombin + CaCl2 + and genipin | Inkjet, extrusion |
10 to 60 mg/mL | 75% | Neural constructs [55], skin [56], blood vessels [57], cardiac tissues [58]. | 55 |
| Hyaluronic Acid | Photopolymerization, click chemistry, chemical group functionalization (thiol, methacrylate etc.), crosslinking agents (gold, PEG) |
Extrusion | 2.5% | 64.4 ± 12.2% (21 days) |
Bone and cartilage engineering [5], tumor models [59]. |
5 |
| Alginate | Divalent ions | Inkjet, extrusion, laser |
1.5 to 3% | High (90 to 95%) (10 weeks) |
3D-printed ear [9], vascular tissue [60], and bone printing [61]. | 9 |
| Agarose | Thermal crosslinking (31 to 36 °C) | Inkjet, extrusion |
0.3% | 97% | Arterial bifurcation [29] | 29 |
| Chitosan | Chemical crosslinking Schiff-base reaction (genepin, glutaraldehyde) photo crosslinking |
Extrusion | 90:10 (ratio of chitosan to EDTA- modified chitosan) |
95.6 ± 1.3% (36 h) |
Cartilage engineering [62], drug delivery [63], wound repair [64]. | 62 |
| Silk | Physical crosslinking (hydrophobic, hydrophilic, and hydrogen-bonding interactions), photo polymerization, enzymatic (horseradish peroxidase) | Extrusion | 30% (chemically modified by methacrylate) |
High (4 weeks) | Tracheal ring [65]. | 65 |
| Gelatin | Thermal gelation (4 °C), chemical crosslinking by Schiff-base reaction (glutaraldehyde), photopolymerization |
Extrusion | 10% | 78.57 ± 3.57% (Day 8) |
Bioprinted ovaries [66]. | 66 |
| Gelatin Methacrylate | Photo crosslinking, ionic interactions | Digital light printing, extrusion |
13.3% | High (Day 10) | Nerve guidance conduit [67]. |
67 |
| Matrigel | Thermal gelation (37 °C) |
Inkjet, laser |
2% | 100% (72 h) |
Co-cultures of ovarian tumor and human fibroblast cells [68]. |
68 |
| Synthetic | ||||||
| PEG | Physical, chemical, photo crosslinking | Extrusion | 20% | High | Alveolar model [69]. | 69 |
| Poloxamers (Pluronic (F-127)) | Self-assembly (thermal gelation > 37 °C), photo crosslinking | Extrusion | 20% (17% pure F-127, 3% acrylated F-127) | 86.3% (Day 14) |
Chondrocyte culturing [70]. |
70 |
| Silicone | Chemical crosslinking | Inkjet, extrusion | Commercially available silicone (Ecoflex 50, Ecoflex30) | High (120 h) | Meniscus implants [71]. | 71 |