Imagine what the implications would be if many diseased or non-functioning human body parts could be replaced without using implant surgery or prostheses, but by using manufactured body parts. It would mean that:
- Life expectancy will increase substantially, and even accidental death due to damage to body parts could be significantly reduced.
- Celebrities and entertainers who use cosmetic surgery in order to stay youthful could purchase and change body parts as is they were used clothing.
- Criminal characters could impersonate others or change their physical features in order to avoid capture.
- Some people may change their ethnic or racial features in order to fare better in a racially biased world.
Before going too far into this discussion, it is necessary to recognize that significant differences exist between functional complexities of body parts. For example, although the functions of legs, arms, ears, nose, teeth, and certain body parts are complicated, some of these body parts could be manufactured. However, even from a layman’s viewpoint, the functions of body parts such as the heart, the kidneys, the brain, or the lungs are so complex that they will probably be impossible to manufacture.
Currently, surgical solutions for replacing diseased or non-functioning body parts involve the use of implants and prostheses. Within the past decade, research reports suggest that CAD/CAM and 3D printing technology are on the verge of creating certain human body parts. Is it reasonable to expect this technology to succeed?
What Obstacles Prevent The Creation Of Replaceable Body Parts?
It is common knowledge that many human body parts, including even complicated body parts, can be replicated with 3D printers. For example, the Wake Forest Institute for Regenerative Medicine used a 3D printer to create a kidney-shaped structure, based on a medical CT scan of a real kidney. However, the printed kidney was non-functional, because it lacked the intricate inner cellular structures (with dimensions on the order of 150 to 200 microns) that a real kidney requires. Similarly, it is possible to print a complicated organ such as a liver, but it will be non-functional.
Tissue engineering has made great progress in finding biocompatible materials for body parts which can be used in 3D printers. However, there is a major obstacle to overcome in order to create a functioning body part. This obstacle is termed “vascularization”. Vascularization requires that networks of veins, arteries, and capillaries that a functioning body part requires should be replicated in the 3D-printed body part. Without the presence of these networks, the body part cannot nourish the body’s tissues and filter out waste. Actually, published medical articles indicate that this obstacle of vascularization is much more complicated than it seems. In addition to the obstacle of vascularization, an additional obstacle of tissue rejection exists, which makes organ implantation between human bodies quite risky. Because history indicates that insurmountable problems eventually get solved by human ingenuity, it is not a good idea to dismiss as fictional the possibility that 3D printers could create functional body parts.
Have Any Functional Body Parts Been Created with 3D Printing?
The most common body parts that 3D printers can produce are prostheses and implants which do not suffer significantly from the obstacle of vascularization.
Body parts which fall into this category include body parts which rely on bone tissue. Some of these body parts are prosthetic legs, hip implants, and dental implants.
The following list highlights some of the notable achievements in 3D printing of more complex body parts, and the use of 3D printing for use in surgical procedures:
- Bio-printing of human bone tissue has made it possible to print prosthetic arms and legs. However, it is a challenge to print replacement fingers or arms because the printed parts lack functional nerve endings and blood flow network.
- A patient’s skull was printed and replaced in a surgical procedure at University Medical Center Utrecht, in Holland.
- Ears were printed at Cornell University by using ink jells containing living cells. The printed ear was injected with bovine cartilage cells and rat collagen and incubated for 3 months in order to make it usable. The success of this procedure remains to be seen.
- 3D printing has been used to print synthetic skin directly onto the wounds of burn victims at the Wake Forest School of Medicine. The ink used for printing consists of enzymes and collagen which were layered with tissue and skin cells after printing, in order to form the skin graft.
- Queensland University of Technology in Brisbane, Australia has used 3D printing to regenerate breast tissue with fat cells drawn by liposuction from the stomach area. The fat tissue was injected into a scaffold which dissolved into regenerated breast fatty tissue in two to three years. This procedure is benefitting women with mastectomies.
What Progress Is Being Made In 3D Printing Of More Complicated Body Parts?
If 3D printing of simpler functional body parts becomes a reality, the next step will be to print human organs, and perhaps to imagine printing a hybrid human being who can exchange worn out and defective organs with new ones. It is not surprising that research is ongoing to print functional human organs such as a kidney, liver, and other vital organs.
What Realistic Expectations For 3D Printing Of Body Parts Are Reasonable?
As crazy as the idea sounds, who knows whether human ingenuity and imagination could create a replaceable human body?
Perhaps the idea that this could happen in the future is not too fictional to become reality, but it is highly unlikely that technology can marry the physical body to the non-physical part of human life (such as memory, love, hate, emotions, or reasoning).
Because it is outside the scope of this article to address the origin of life or theological issues, it is up to the reader to determine how far 3D printing of body parts could go.