Three dimensional (3D) bioprinting is the use of 3D printing like techniques to combine cells, growth factors, and biomaterials to fabricate biomedical parts that maximally imitate natural tissue characteristics. Generally, 3D bioprinting uses the layer-by-layer method to deposit materials known as bioinks to create tissue-like structures that are later used in medical and tissue engineering fields. Bioprinting covers a broad range of biomaterials.
In addition, 3D bioprinting has begun to incorporate the printing of scaffolds. These scaffolds can be used to regenerate joints and ligaments.
The process principally involves preparation, printing, maturation, and application.
- Pre-bioprinting involves creating the digital model that the printer will produce. The technologies used are computed tomography (CT) and magnetic resonance imaging (MRI) scans.
- Bioprinting is the actual printing process, where bioink is placed in a printer cartridge and deposition takes place based on the digital model.
- Post-bioprinting is the mechanical and chemical stimulation of printed parts so as to create stable structures for the biological material.
Several 3D bioprinting methods exist, based on extrusion, inkjet, acoustic, or laser technologies. Despite the various types, a typical bioprinting process has a more-or-less standard series of steps:
- 3D Imaging: To get the exact dimensions of the tissue, a standard CT or MRI scan is used. 3D imaging should provide a perfect fit of the tissue with little or no adjustment required on the part of the surgeon.
- 3D Modeling: A blueprint is generated using AutoCAD software. The blueprint also includes layer-by-layer instruction in high detail. Fine adjustments may be made at this stage to avoid the transfer of defects.
- Bioink Preparation: Bioink is a combination of living cells and a compatible base, like collagen, gelatin, hyaluronan, silk, alginate or nanocellulose. The latter provides cells with scaffolding to grow on and nutriment to survive on. The complete substance is based on the patient and is function-specific.
- Printing: The 3D printing process involves depositing the bioink layer-by-layer, where each layer has a thickness of 0.5 mm or less. The delivery of smaller or larger deposits highly depends on the number of nozzles and the kind of tissue being printed. The mixture comes out of the nozzle as a highly viscous fluid.
- Solidification: As deposition takes place, the layer starts as a viscous liquid and solidifies to hold its shape. This happens as more layers are continuously deposited. The process of blending and solidification is known as crosslinking and may be aided by UV light, specific chemicals, or heat.
- For pharmaceutical development, 3D bioprinting offers a means of testing drugs faster, at a lower cost, and with better biological relevance to humans than animal testing.
- In the biomedical devices field, 3D bioprinting has enabled new developments such as sugar stents to help surgeons join veins with fewer complications, and systems for improved drug delivery, among others.
- As bioprinting evolves, it will become possible to use a patient’s own cells to 3D print skin and bone grafts, organ patches, and even full replacement organs.
- Personalized and regenerative medicine continues to grow in popularity, and 3D bioprinting will give doctors and researchers the tools to better target treatments and improve patient outcomes.
- 3D bioprinting technologies enable the digital fabrication of living constructs encapsulating cells, biomolecules, and biological moieties in spatially patterned structures.
- 3D bioprinting can be used to print tissues and organs to help research drugs and pills