By Pierre-Antoine Arrighi – email@example.com
3D printing is a manufacturing technique using a repetitive process of disposing layers after layers, it offers a great flexibility on the type of objects you can build, which can actually be very complex and detailed: much like a human organ for instance. Of course, scientists are now able with 3D printing to build research gears and accessories, and also tools with very specific features, all of that at a relatively cheap cost [1,2,3].
However, what are current scientific achievements? This article presents recent progress and challenges that are making science move forward faster in various scientific fields from Physics, Biology, or Chemistry to Medicine.
More than the ability to build advanced labware for a fraction of the market price, 3D printers have produced 3D printed objects that have revolutionized various scientific fields.
In fact, turning computer data into physical objects, 3D printers inspire creativity enabling real innovations and surely unexpected discoveries in a wide range of scientific applications.
Energy: 3D printed batteries.
Figure 1. Stack of printed electrodes. Scale bar is 200 µm.
A team based at Harvard University and the University of Illinois at Urbana-Champaign printed precisely interlaced stacks of tiny battery electrodes, each less than the width of a human hair. This 3D printed system (Figure 1) exhibits high area energy and power densities and may find potential application in autonomously powered microdevices .
Physics of materials: 3D printed granular molecules.
Shape of a granular material is an inexhaustible parameter, making its systematic exploration infeasible. A smart paper shows that the role of particle shape can, however, be explored efficiently when granular design is viewed in the context of artificial evolution. By introducing a mutable representation for particle shapes, the authors demonstrate with computer simulation and 3D-printing particles how shapes can be evolved. This approach facilitates the exploration of the role of arbitrary particle geometry in jammed systems, and invites the discovery and design of granular matter with optimized properties .
Zoology: 3D printed titanium bugs.
Figure 2. Close view of the printed titanium bugs.
3D bugs have been printed to demonstrate new potential for entomologists studying the anatomy of miniature creatures by enabling them to physically handle the insects and study their features up close (Figure 2). Zoologists believe this technology will soon enable them to determine characteristics, such as gender, and examine surface characteristics which are otherwise difficult due to the insect size .
(i)3D printed metal parts.
Figure 3. Titanium 3D structure.
As the space industry needs to be more green, the European Space Agency is currently developing 3D-printed metal components (Figure 3 ) for use in spacecraft, planes, and even nuclear fusion applications. The Amaze project (loose acronym for Additive Manufacturing Aiming Towards Zero Waste and Efficient Production of High-Tech Metal Products) brings together 28 institutions to develop new metal components which are lighter, stronger and cheaper than conventional parts .
(ii)3D printer into space.
A robotic arm designed by R. Hague from The University of Nottingham.
NASA is preparing to launch a 3D printer into space next year, a toaster-sized game changer that will greatly reduce the need for astronauts to load up with every tool, spare part or supply they might ever need. Nasa selected Made in Space’s 3D printer for a space test scheduled to go ahead in 2014, after considering 3D printer designs from more than a dozen companies .
Chemistry: 3D printed chemical reactions.
A custom 3D printer in which molecules can take “plans” for molecules and print them. Cronin group in the University of Glasgow proposed using a build-it-yourself 3D printer called Fab@Home to fabricate plastic reaction vessels from a quick-drying silicone polymer . Thanks to this system, Cronin and his colleagues were able to produce an organic heterocycle and two inorganic nanoclusters that had never been seen before. This 3D printer may soon become a common, but still potentially revolutionary, sight in chemical laboratories .
When a part of a body cannot achieve its duty anymore, one can rely on 3D bioprinting transplants. Bioprinting means “biological printing.” It is a very new and promising achat viagra en ligne pas cher area of pharmaceutical and medical research that involves “printing” biological matter and material for use in prosthetics, replacement organs, veins and human tissues.
Prosthetics are a great fit for 3D printing because they are mostly made of plastics and they require to be very specifically designed to best fit their user. It is now economically possible to make every model a tailored one, all dedicated to the body’s properties of the future owner. For example, Some successes have been reached for the fabrication of outer organs such as ears , skin , or robotic arms and hands (Figure 4).
Recently, a skull surgery transplant  was even successfully carried out, using 3D printing to create a missing portion of a patient’s skull. Let’s finally highlight the achievements of a US company, Bespoke Innovations which is using 3D printed to create reliable and custom-made prosthetic legs .
Another very rising and promising application is tissue manufacturing . The fabrication of a 3D functional tissue made of several cell types is a 3-step process :
1- Cells are sorted, multiplied and differentiated.
2- Cells or cell aggregates are embedded to enable subsequent hierarchical tissue building.
3- The obtained 3D structures are matured in a perfusion reactor to create a vasculature system.
3D printing of cell aggregates thus allows bioengineers to assemble complex tissues. Proof-of-principles include for instance pieces of both blood vessel and liver tissues [15,16, 17,18,19] .
Organs and organs-on-chip.
A whole 3D printed heart from the recipients’ own cells.
Tissue engineering techniques should soon be available for inner organs . To go further, scientists have focused on devices called “organs-on-chip” [20,21]. It consists in recreating 3D functional bodies of humans or model organisms as a whole allowing observation as well as manipulation. A device is produced thanks to standard microfabrication techniques derived from chip industry. Then, cells are seeded mimicking the studied organ. Finally, experiments are achieved by varying some key parameters (e.g. drug concentration, mechanical stress, electric potential). The approach is characterized by better precision, reproducibility, and throughput. Up to now, breast, lung, eye, kidney, brain, liver, gut, and bone have been investigated (Figure 5) [20,21,22]. Finally, this represents a relevant and direct method to study human physiology .
For a long time, the 3D printing techniques has been extensively used in science and medicine but as these fields are relatively away from the public’s attention, not a lot of light has been shed on the recent advances. The future is indeed full of outstanding promises: from prototyping and customizing labware, repairing a broken limb to building cheap and efficient prosthetics, or even replacing a damaged organ like a heart or an ear.
L. K. Wolf, 3D printers move into research labs. Chemical & Engineering News, 91, 44-45, 2013.
J. M. Pearce, Building research equipment with free, open-source hardware. Science, 337, 1303-1304, 2012.
C. Zhang, et al., Open-source 3D-printable optics equipment. PLoS One, 8, e59840, 2013.
 K. Sun, et al.,3D printing of interdigitated Li-ion microbattery architectures. Advanced Materials, 25, 4539–4543, 2013.
M. Z. Miskin, et al., Adapting granular materials through artificial evolution. Nature Materials, 12, 326-331, 2013.
 http://www.aniwaa.com/3d-printing-in-space-coming-to-reality-in-2014/ http://www.nasa.gov/mission_pages/station/research/experiments/1115.html
 C. J. Richmond, et al., A flow-system array for the discovery and scale up of inorganic clusters. Nature Chemistry, 4, 1037-1043, 2012.
J. Evans, Print your own lab. Chemistry&Industry, 1, 16-18, 2013.
M. S. Mannoor, 3D Printed Bionic Ears. NanoLetters, 13, 2634–2639, 2013.
D. L. Elbert, Bottom-up tissue engineering. Current Opinion in Biotechnology, 22, 674-680, 2011.
 C. Khatiwala, et al., 3D cell bioprinting for regenerative medicine research and therapies. Gene Therapy and Regulation, 7, 1230004-1230023, 2012.
J. M. Kelm, et al., A novel concept for scaffold-free vessel tissue engineering: Self-assembly of microtissue building blocks. Journal of Biotechnology, 148, 46–55, 2010.
G. Forgacs, Perfusable vascular networks. Nature Materials, 11, 746-747, 2012.
E. Cimetta, et al., Bioengineering heart tissue for in vitro testing. Current Opinion in Biotechnology, 24, 926-932, 2013.
C. Lumi, et al., Human-on-chip for therapy development and fundamental science. Current Opinion in Biotechnology, 25, 45-50, 2014.
 V. Mironov, et al., Organ printing: from bioprinter to organ biofabrication line. Current Opinion in Biotechnology, 22, 667–673, 2011.
D. Huh, et al., From 3D cell culture to organs-on-chips. Trends in Cell Biology, 21, 745-754, 2011.