3D bioprinting is a rapidly growing field, but what exactly does it entail? While the capabilities of bioprinting have not yet reached the level depicted by popular culture, we are on the brink of a bioprinting revolution and fully transplantable organs should be feasible within the next decade. The potential of 3D bioprinters is immeasurable, with promise in altering the very limits of the human lifespan itself. For those curious about this new technology, here are some basics of bioprinting.
Technology - how it works
A bioprinter works in a similar way as a 3D printer. It moves in the x, y and z directions to deposit materials in a layer-by-layer fashion but in this case, instead of extruding molten plastic, it extrudes biomaterials and cells. The three most common types of bioprinting technology are (1) the extrusion based system, (2) laser-assisted deposition system and (3) inkjet based bioprinting system. Depending on the desired end-user application, each technology platform offers its own set of advantages and disadvantages. Extrusion-based bioprinters are the simplest in design and can be very affordable but does not offer the highest resolution. On the other hand, while laser-assisted bioprinters can provide a high precision and resolution, it is quite cost prohibitive and sophisticated.
Materials - what it prints
The materials used in bioprinters often also coined as “bioinks” include a variety of natural or synthetic biopolymers. These materials have a unique crosslinking chemistry that will allow them to transform from the liquid to a solid state. Some biopolymers exhibit thermosensitivity meaning they would change state when the temperature changes. A good example is agarose which is in liquid state at higher temperatures (>40 oC) and solidifies into a gel at lower temperatures, just like Jello. Other biopolymers such as alginate, a natural polymer derived from brown seaweed, turns into a gel when it is crosslinked in the presence of calcium ions (Ca2+).
Cells - the living things
What makes a bioprinter unique is that it is used to print cells. What kind of cells? Any and many. Scientists have experimented with all kinds of mammalian cells from skin to muscle to stem cells for growing 3D tissues and tissue models. Cells and biopolymers serve as building blocks for creating a 3D tissue. The bioprinter allows precise and specific deposition of cells, as individuals and/or groups of cells into specific locations within the engineered tissue.
The primary application of bioprinting has been for tissue engineering and drug discovery. The goal of tissue engineering is to regenerate and/or replace damaged tissues and organs in the future. Today, bioprinted 3D tissue and organ models are being used in the pharmaceutical industry for drug screening applications. Bioprinted 3D tissue models provide a better mimicry to living tissues in our body compared to current 2D cell culture techniques and reduces our reliance on animal models which do not correspond well to human physiology. Today bioprinted human skin models are gaining popularity for cosmetics testing. In the future, fully functional bioprinted organs such as a 3D printed kidney or heart can be used for organ transplants.
To learn more about bioprinting, take this introductory online course.