A 3D printer printing the letters "3D."

Image source: Getty Images.

3D printing is taking the world by storm and promises to transform nearly every industry and touch upon many facets of our lives. This incredible technology -- which uses a digital model to build an object layer by layer -- isn't new, but it's made such rapid advances in the last several years that its applications have ballooned in size and scope.

Here are nine things that many folks probably didn't know could be 3D-printed.

Schematic of kidneys inside human body.

Image source: Getty Images.

1. Human tissues and organs

3D printing's most amazing healthcare application has to be the printing of living human and animal cells to form tissues and organs, which is often called "bioprinting." 

The Wake Forest Institute for Regenerative Medicine in North Carolina has bioprinted human tissues and select flat, non-solid organs that have been transplanted into patients. Organovo (NASDAQ:ONVO) uses the tech to produce human liver tissue assays to help pharmaceutical companies speed up the new drug-development process. Last month, 3D Systems (NYSE:DDD) announced it was entering the bioprinting field via a partnership with United Therapeutics. The burgeoning industry's ultimate goal is to print fully functional solid organs (such as the liver, kidneys, and heart) that can be transplanted into people in need. 

Colorful coral reef and fish.

Image source: Getty Images.

2. Coral reefs

Coral reefs on ocean floors across the globe have been experiencing a bleaching crisis, which is destroying them and their brilliant colors. Scientists largely blame the warming of the climate. Reefs are crucial to marine life, which in turn is crucial to us humans at the top of the food chain.

Many experts believe that 3D printing offers the best hope of slowing the damage to the reefs. The tech can replicate their natural texture and structure, which is vital to attracting sea life. The first experimental installation of 3D-printed coral reef was submerged in the Persian Gulf in 2012. Such installations are now also in place in the Mediterranean, the Caribbean, and Australia. Fabien Cousteau, grandson of the legendary ocean explorer Jacques Cousteau, began the project in the Caribbean in January. 

White pills spilling out of a container onto a blue table.

Image source: Getty Images.

3. An FDA-approved drug

In August 2015, the U.S. Food and Drug Administration gave the green light to a 3D-printed drug -- a first ever. The drug is Aprecia Pharmaceuticals' Spritam, an epilepsy drug that became available in March 2016.

The privately held, suburban Philadelphia-based company manufactures Spritam using its ZipDose 3D-printing tech, which produces a porous formulation that quickly disintegrates with a sip of liquid. The formulation is targeted at the many epilepsy patients who have a condition that makes it difficult for them to swallow pills.

Pair of adidas' Futurecraft 4D running shoes.

adidas' Futurercraft 4D. Image source: adidas.

4. A mass-produced athletic shoe

Last month, adidas AG (OTC:ADDYY) announced that it's teaming with 3D printing start-up Carbon to produce a new line of running shoes with 3D-printed midsoles. Unless another industry player makes a quick dash soon, adidas will become the first athletic shoe company to make a mass-market shoe with a 3D-printed midsole.

Adidas plans to offer 5,000 pairs of its new shoe for retail sale later this year, produce more than 100,000 pairs by the end of 2018, and then quickly ramp to making millions per year. The most awesome thing for athletes, as well as for folks who just want a great-fitting and comfortable shoe, is that customized versions of the shoe are on the horizon.

Dubai skyline at sunset.

Dubai skyline. Image source: Getty Images,

5. Complex buildings, including a planned skyscraper

3D printing has enormous potential across mainstream architecture. Many experts believe the tech could significantly speed up building construction, unleash previously impossible design possibilities, and reduce cost.

There have already been some rather complex buildings constructed using 3D printing, including the world's first fully functional 3D-printed office building in Dubai, an approximately 2,400-square-foot single-story structure that was completed last year. The most ambitious project within this realm was announced earlier this year: Dubai-based construction technologies company Cazza plans to build the world's first 3D-printed skyscraper in the United Arab Emirates. 

D-Shape's founder stands with arms outstretched on the bridge his company 3D-printed.

D-Shape founder Enrico Dini. Image source: D-Shape Enterprises. 

6. A bridge

The world's first 3D-printed bridge opened to the public in December. The pedestrian bridge was designed by a team led by the Institute of Advanced Architecture of Catalonia, installed by ACCIONA Construction, and produced by Enrico Dini's D-Shape technology. The bridge spans a stream in Castilla-La Mancha Park in Alcobendas, Madrid. It's printed in micro-reinforced concrete, and is 12 meters long and 1.75 meters wide, or approximately 39.4 feet by 5.7 feet.  

The bridge's organic design fits in with the surrounding nature. The use of a computational design method allowed the team to maximize the structural performance, while minimizing the amount of material use. 

An Arkyd-6 spacecraft with Earth in background.

Image source: Planetary Resources.

7. Objects made from asteroid material

In January 2016, privately held Planetary Resources and its 3D printing partner, 3D Systems, awed space fans at the Consumer Electronics Show when they showed off the first object ever 3D-printed from asteroid material, a model of a spacecraft. The material, sourced from an impact, has a composition similar to refinery-grade steel. 

Planetary Resources is building spacecraft for asteroid mining, a nascent industry that's expected to boom in the coming years. Its two Arkyd-6 spacecraft are slated to launch on prospecting missions this year.

The International Space Station orbiting Earth.

The International Space Station orbiting Earth. Image source: Getty Images.

8. Objects 3D-printed in space

The ultimate success of the space economy depends upon it being self-sufficient. That means items needed in space -- a list that will grow exponentially when humans colonize other planets -- will need to be produced in space.  

Neither 3D Systems nor any of the other companies that currently sell 3D printers has the capability to make one that can be used in a zero-gravity environment. Enter Made In Space to the rescue! Last March, as part of a NASA contract, the start-up equipped the International Space Station with a specially designed permanent 3D printer and related equipment. The "Additive Manufacturing Facility" is available to NASA and other entities to use. 

Close-up of a man's hands using  a cell phone in a parking lot.

Image source: Getty Images.

9. Electronic components for consumer and industrial applications

Electronic circuitry is another amazing "ink" that is being used in 3D printers. Xerox is one notable entity working on printing conductive materials, but privately held Optomec is currently the company to watch here. 

The Albuquerque, New Mexico-based company's Aerosol Jet technology enables its customers to 3D-print integrated electronics onto plastic, ceramic, and metallic structures at incredibly fine resolutions. This tech is being used for the high-volume production of 3D-printed antennas and sensors that are integrated into products ranging from mobile devices to industrial components. General Electric (NYSE:GE) -- which has been ramping up its 3D-printing muscle lately -- invested in Optomec last year.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.