If you’ve heard about 3D printing in the news, it’s probably because someone has printed something remarkable. Items like bike parts, miniature toys, or even VR goggle pieces are just some examples of things that can be made in a 3D printer. The scope of your project depends on the size and sophistication of your 3D printer and your own imagination. A quick browse through YouTube will show you that with the right software, you can print just about any solid object that will fit in the printer’s manufacturing bay.
So what happens when the worlds of medicine and 3D printing combine? It’s a question that more and more engineers and doctors are beginning to ask. While organs and inanimate objects are two very different things, the limits of 3D printers are only just being explored. By combining the rules of 3D printing with our understanding of the human body, we can achieve breakthroughs the likes of which the printing and medical industries have never seen before.
History of medical printing
Medical printing history is commonly thought to have begun in the 1970s, but inventor Charles Hull came up with the term stereolithography in 1984. Stereolithography is the process of using light to bind molecules together and form hardened 3D solids. The medical industry still makes good use of stereolithography today in order to create models in preparation for analysis, diagnosis, and implantation. Intricate layer by intricate layer, a model can be produced to give a static imitation of a body part based on initial data gathered (usually from a computer). Since the invention of stereolithography, researchers and inventors alike have been searching for a way to bring organs to life outside the human body.
The next ambitious project that 3D printing engineers are tackling is bioprinting. Organ failure is a common medical issue in today’s world. The human body has a limited ability to completely regenerate or heal compromised organs. Transplants from person to person are currently the preferred method of solving severe organ and internal damage. Even so, this method doesn’t have a one-hundred percent success rate due to a number of factors, not the least of which is that donor organs are in short supply. This is where 3D bioprinting comes in.
3D bioprinting is the use of 3D printing techniques to create organs or other biomedical materials from their base cells. Those organs or materials would then serve as acceptable substitutes for damaged parts within the human body. That means that people who are waiting for an adequate transplant wouldn’t have to do much waiting at all. 3D bioprinting would still take time to ensure the printing was a success, but it would be a far better solution for someone who doesn’t know when or if they will ever get an acceptable transplant. The ultimate goal with bioprinting is to improve transplant efficiency, success rate, and affordability.
How 3D Bioprinting works
Organs are no simple subject. Just ask any doctor or surgeon and they’ll tell you just how delicate and complicated our organs are. Cells, arteries, and muscles all have to work in concert with little to no error to ensure someone is living a healthy and productive life. Replicating organ architecture and function are the greatest hurdles researchers are trying to overcome. Creating a life-size organ isn’t a problem, but getting cells to do what we want them to do can be tricky, especially when you get down to the biochemical level.
The basis of bioprinting is first being able to replicate organ structure, texture, and properties at the cellular level. While replicating organ function is still a long way off, organ structure is a crucial first step on the road to success. To accomplish that, many scientists and inventors are turning to a relatively new invention called bioink.
Bioink is the industry term for the materials that a 3D bioprinter use to create and grow a particular organ. Bioinks are a gelatinous material that can envelop living cells as an organ is being constructed. With a little mixture of water, these bioinks can become a good balance of flexibility and sturdiness. This is done in order to improve the similarities between naturally grown organs and 3D printed organs. Bioinks would replicate the complex structures of different organs and enable them to conduct the same tasks as naturally-grown organs. Think of it this way:
- Patient cells >>> bioink >>> bioprinter >>> bioprinted organ
This way, there is little chance of the body rejecting the new organ. The body would recognize the bioprinted organ as the same damaged organ, but much healthier and part of the patient's own body. However, we cannot simply lump cells together and expect a pair of working lungs or kidneys to grow out of them. As we mentioned earlier, the true hurdle is getting those bioprinted organs to imitate naturally-grown organ function.
Bioinks require a different set of rules in production than traditional 3D printed materials. Certain bioinks provide properties that allow cells to thrive without overgrowing or developing complications. Outside of our body, cells are very delicate and vulnerable to environmental conditions. One has to be aware of:
- Printing Temperature - Usually low at around the 30°C / 86℉ mark
- Printing pressure - What type of nozzle is used and the forces used to print
- Type of bioink - Many forms of bioink involving gelatin exist
- Cell environment - Cells need food to live, grow, and multiply
The list goes on but the lesson to be learned is that 3D bioprinting is its own beast within the 3D printing industry. We only wish things were as simple as pressing the “print” button. Now that we’ve looked at some of the materials and conditions involved, let’s take a look at the printers themselves.
Types of Bioprinters
Bioprinters are a very small subset of a still relatively new 3D printing industry. Your average consumer isn’t going to get much use out of these 3D bioprinters without the right expertise and materials. Bioprinter sale is primarily limited to laboratories, organizations, or universities that are experimenting with ways to either improve the printer itself or bioprinting techniques in general.
Here are the three most common types of bioprinters, most of which use some form of bioink:
- Extrusion printers - Use pressure and nozzle diameter to print layer by layer
- Inkjet printers - Use heat to expel ink droplets onto a printing surface
- Laser focused printers - Use lasers to heat biomaterials onto a receiver in droplet form
There are pros and cons to each of the three types. Most disadvantages have to do with cost and how each printer deals with the delicacy of bioinks and actual cells. The pinpoint accuracy of laser focused printers means they are today’s preferred machines. However, extrusion printers are gaining traction because of their ability to directly print cells layer by layer. This method ensures cells are interacting with each other as soon as they are printed in even portions.
Westworld and its bioprinting implications
A work of fiction that sparks questions in 3D bioprinting is Westworld. We’ll give you a quick premise if you haven’t seen it yet. In the near future, Westworld is an 1800s, western-themed amusement park staffed by “hosts.” These hosts are near-human-like robots who act out whatever narrative the guests (real humans) wish to embark on. That all seems well and good until some of the hosts begin retaining the memories they had before they are “killed” or “recycled.” The word you’re probably looking for is sentience, a word that reminds us of films such as Terminator, Alien, Battlestar Galactica, or Blade Runner.
But what do bioprinting and Westworld have in common? The creation of complex organic material from scratch. In Westworld, hosts are born and recycled in laboratories most likely using advanced, yet-to-be-determined, bioprinting techniques. Since there are many other host/guest driven theme parks in the Westworld universe, one can safely assume that hosts are “printed” at a rapid rate to keep up with demand. Our hope is that at some point, our bio-printing techniques can be just as fast and efficient as Westworld’s (perhaps without the world-altering problems that ensue).
Westworld vs. the Real-World
So how far are we from a world like Westworld? In terms of the reality of the hosts, very far off. Creating organic life that thinks and acts as humans do is a concept currently beyond our reach. While bioprinting concepts and techniques exist, we still have yet to standardize them in a way that will become common practice.
Current practices focus on individual body parts and materials to be used in already sentient beings - us - and is gaining momentum, but creating a “host” grown in the lab like Westworld is still science fiction. Sure, organs and limbs are one thing, but entire personalities like the hosts in Westworld is something entirely different.
Furthermore, the evolution of those personalities as actual humans interact with them is just something we can’t comprehend right now. Authors, writers, and other creative minds have imagined artificial intelligence in thousands of possible ways. However, the technology and materials used to recreate those scenarios simply doesn’t exist. (See our HP Tech Takes article on OpenAI
so get an idea of just how close we are, though.)
So why is Westworld, in particular, gripping audiences around the world? Credit is certainly due in large part to the acting, direction, and progression of the story. However the underlying point is that the beings we seemingly grow in labs, which then start forming their own personalities, motives, etc., unnerve us. That unnerving factor is capitalized by the fact that these beings are indistinguishable from humans.
How are 3D printing and bioprinting working together?
Bioprinted organs cannot be created using the same methods as a 3D printed bike part or a miniature toy. However, most areas of medicine already employ some form of 3D rendering like stereolithography in order to spot problems within the body. The areas where industrial 3D printing and bioprinting overlap is in the design process. Design won’t be as simple as creating a 3D image that looks like an organ. The key to advancing bioprinting technology will be going down to the smallest possible detail, layer by layer, to ensure the organ architecture is medically sound.
A term you might hear being used in bioprinting and 3D printing terminology is voxel. A voxel is the 3D cousin of the 2D pixel. A voxel represents a certain value within a 3D space, but with many more properties than a pixel. You can give that voxel different color properties, material strength, and flexibility. A single voxel by itself doesn’t represent much, but when combined with other voxels, it can create complex structures. Understanding how each voxel fits in a puzzle will be one of the keys to making a 3D bioprinted organ work the way we need it to.
How is HP using 3D printing?
HP’s technology appears in just about every industry you can think of - from print media to gaming. One area that they are carrying the torch in is 3D printing. HP Multi Jet Fusion (HP MJF)
is currently the pinnacle of HP’s 3D printing technology, set to transform the way the world designs and manufactures. While not designed for bioprinting, HP Jet Fusion 3D Printing Solutions (powered by HP MJF technology) are helping unlock new applications
in medical and healthcare industries all over the world – including medical devices and equipment, customized prosthetics and orthotics, dental aligners and anatomical models.
Don’t expect to see the HP Multi Jet Fusion pumping out organs, though. HP Multi Jet Fusion is outfitted specifically for industrial-level production of intricate and complex parts. But perhaps the lessons to be learned here is that whether you’re creating a bike pedal or a kidney, the design processes are similarly complex. Taking the time to ensure our designs are precise will better the chances of bioprinting success.
Bioprinting in today's news
Now that we’ve exhausted your brain on bioprinting and all it has to offer, where are we today? Currently, the rush is to develop ever more intricate bioprinters and bioinks that take into account the delicacies of our organs.
- In August of 2019, UPM Biomedicals developed a new hydrogel called GrowDex-T® that allows for improved imaging of cells in 3D 
- In September of 2019, BrinterTM introduced a 3D bioprinter whose unique feature can be used to test for drug toxicity 
- Researchers at Carnegie Mellon University released the designs for a smaller, DIY bioprinter as open source. The projected cost for this printer is around $500 
It seems like there is a new aspect of bioprinting being invented every month. The prospects and advantages of bioprinting looking bright for the future. Let’s just try and avoid the more mind-bending storylines that Westworld offers.