Although 3-D printers have been around since 1984, the technology has only been considered new and cutting-edge here in the 2010s. Last year, the global market for 3-D printers and services was worth $2.2 billion -- a 29% year-over-year jump from 2011 -- and it is projected to continue climbing to $8.4 billion by 2020.

One of the most exciting developments in 3-D printing is bioprinting -- the printing of human tissues -- which could eventually lead to the production of 3-D-printed organs and eliminate the need for organ transplant waiting lists.

Organovo (NASDAQ:ONVO), the only publicly traded 3-D bioprinting company, has captured the public's imagination with visions of a future in which replacement body parts can be printed.


Organovo's 3D bioprinter. Source: Company website.

Let's not get ahead of ourselves yet, though. Organovo currently has only one main product in development: a 3-D-printed liver assay for lab tests, which can survive for 40 days and be tested with multiple doses of the same drug -- two key features that older two-dimensional cell cultures lack.

If successful, Organovo's 3-D-printed liver assays could be a game-changing product for the pharmaceutical industry, since 25% of failed or withdrawn drugs between 1990 and 2010 were caused by unexpected liver toxicity during late-stage trials. After the expected approval of its liver assay in late 2014, Organovo might one day develop an entire 3-D-printed liver before moving to other organs such as the heart.

Although that future could be decades away, Organovo's bioprinting technology could also disrupt the health-care industry in more subtle ways. Let's look at three possible disruptions that could affect companies such as Boston Scientific (NYSE:BSX), Osiris Therapeutics (NASDAQ:OSIR), and Hanger (NYSE:HGR).

Customized organic stents
Boston Scientific, St. Jude Medical, and Abbott Laboratories are leading makers of medical stents, tubes that are placed into blood vessels and inflated. They can either prop open constricted arteries or slowly release a drug to prevent fibrosis (growth of excess tissue) and blood clots.

As we can see from Boston Scientific's most recent quarter, demand for newer drug-eluting stents is easily outpacing demand for older metal ones.



Bare Metal

Percentage of Quarterly Revenue

Boston Scientific Stent Sales

$262 million

$15 million


Source: Quarterly reports.

However, metal or plastic stents can still be rejected by the body as foreign objects, causing inflammation, abnormal tissue buildup, and infection. In addition, stents can migrate to other parts of the body over time and cause internal bleeding.

3-D-bioprinted stents could instead be produced from biocompatible polymers, which could have a milder effect on the body. They could also be custom-fit for each patient's individual needs.

This idea is far from perfect, though -- introducing more organic or biocompatible tissue matter into a body could spur more unwanted tissue growth, the very problem that drug-eluting stents aim to resolve.

Bioprinted stem cell skin grafts
Meanwhile, companies such as Osiris Therapeutics market repair products derived from stem cell tissue.

Osiris' Grafix, which is produced from adult bone marrow stem cells, is a three-dimensional cellular matrix that can be applied directly to chronic wounds such as burns and diabetic foot ulcers. The result is something out of a sci-fi film -- an organic bandage that grows into a patient's skin.


Source: Company website.

However, Osiris' cutting-edge technology hasn't made a profit for the company yet, although it reported a strong 220% year-over-year surge in product revenue last quarter.

Three-dimensional bioprinting could be the answer for Osiris and other companies looking to create similar products. By printing out stem cells, instead of harvesting them, production costs could be reduced and the rate of production could rise dramatically.

That idea was already put into practice earlier this year by scientists at Heriot-Watt University in Edinburgh, Scotland, who have been experimenting with a new method of printing clusters of stem cells at one time.

Bioprinted prosthetic limbs
Although much of the media's attention has been focused on bioprinted organs, bioprinted prosthetic limbs could also soon become a reality. Today, amputees can be fitted with prosthetic limbs manufactured by companies such as Hanger. Hanger's technology has advanced to a level previously believed unreachable -- in 2011, it fitted an amputee with a $95,000 bionic leg that relies on microprocessors, sensors, and gyroscopes to allow the patient to climb stairs, walk backward, and even ride a bike.


Hanger's Genium bionic leg. Source: Company website.

Yet in the future, entire limbs could be completely bioprinted, eliminating the need for artificial limbs. We might even see even cutting-edge bionic systems.

At this year's Royal Society's annual Summer Science Exhibition in London, a team of scientists from the University of Nottingham in England demonstrated a new type of 3-D bioprinting technology, which uses a polymer called polylactic acid and alginate, a gel-like substance, to produce a scaffold shaped like a bone. The 3-D bioprinter then coats the "bone" with adult human stem cells, which can grow into various tissue types.

Actually connecting those bones to human tissue, however, would be the tough part. But considering that we can now bioprint living cells for stem cell grafts, it's not hard to imagine that blood vessels, nerve endings, and muscles could eventually be reconnected as well. There are also neurological hurdles to overcome, as the wiring to a new hand or foot would have to be perfect for the bioprinted prosthetic limb to function properly. Double arm and double leg transplants have been performed in the past, but patients have had to take anti-rejection drugs constantly.

Bioprinted limbs could be extremely expensive because of their use of human tissue, but there is evidence suggesting that regular 3-D-printed prosthetics are already more cost-effective than conventional ones. In September, South African carpenter and amputee Richard Van As and Seattle designer Ivan Owen invented Robohand, a 3-D-printed robotic hand that costs $500, compared with the $10,000-$15,000 price tag for a below-the-elbow prosthesis.

The Foolish takeaway
Stents, skin grafts, and artificial limbs are all sectors that could be significantly disrupted by the rise of 3-D printing and bioprinting.

It's been 63 years since the first major organ transplant ever -- Dr. Richard Lawler's transplant of a kidney -- was successfully performed. Since then, doctors have been able to replace more parts of the body than ever imagined.

However, there are two major flaws: These parts have to either be manufactured with man-made materials or transplanted from a donor. The rise of 3-D bioprinting could nullify both of those flaws, ushering in a brave new world where people simply print out living spare parts for their bodies.
