Bioprinting: Why do we need it?

What is bioprinting and what is it used for?

What is bioprinting?

3D bioprinting is a rapidly growing field, but what exactly does it entail? Much like a 3D printer, it leverages the concept of additive manufacturing to create layers of tissue-like structures often including cells. By using the same tools in 3D design and deposition, scientists can use bioprinting technology to create intricate and sophisticated structures needed to build tissues and organs. 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: What is a bioprinter?

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 is a bioink?

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+).

Can we bioprint an organ?

What makes a bioprinter unique is that it can be 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 constructs that could serve as a foundation for creating more complex organs. While we may not be able to print and grow a fully functional organ just yet, a bioprinter enables precise and specific deposition of cells, as individuals and/or groups of cells into specific locations within the 3D tissue construct.

Application: What is bioprinting used for?

The primary application of bioprinting has been for tissue engineering and drug discovery. The ultimate 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 can be used for organ transplants.