Metamaterials could be one of the most consequential ideas in materials science, and 3D printing is what turned them from theory into objects you can hold, implant, and build a company around. This piece explains what they are, how the field has evolved, and why they matter for medicine’s future. Unlike conventional materials like wood or metal, which derive their properties from their atomic structure, metamaterials derive their unique properties from their design at the microscopic or nanoscopic level. In other words, there could, in theory, be infinite kinds of metamaterials, not limited by natural resources but only by human creativity. One recent example of a metamaterial is “auxetic materials” presented by Dr. Jeong Hun Park. (See video below.) Scientists create these materials by arranging small, often repeating structures (like tiny coils or patterns) in a specific way. The precise structure allows metamaterials to manipulate waves, such as light or sound, or mechanical forces in unusual ways.
What is a brief history of metamaterials?
The prefix “meta” means beyond, and metamaterials earn the name by achieving behaviors that go beyond what any natural material can do, not through their chemistry but through the way their internal structure is arranged.
The intellectual roots run back more than a century. Early work on how waves interact with periodic structures dates to around 1904. In 1967, Soviet physicist Victor Veselago worked out the theory of a material with a negative refractive index, a substance that would bend light “the wrong way”, decades before anyone could make one. [5] Roger Walser coined the term “metamaterials” in 1999, and in the early 2000s the first practical, microwave-frequency metamaterials were finally demonstrated in the lab. [7]
What matters for medicine is what happened next. For its first two decades, the field was dominated by electromagnetic metamaterials, the stuff of optical cloaking, superlenses, and antennas. Much of the historical research related to metamaterials is rooted in microwave engineering and antenna beam shaping that emerged after World War II.[17]
Over the past several years, the center of gravity has shifted to mechanical and acoustic metamaterials, where the engineered property isn’t how a material bends light but how it bends, absorbs energy, changes shape, or transmits force. That mechanical branch is the one now reshaping biomaterials and 3D printing.[1]
What are the key features of metamaterials?
Three ideas define a metamaterial:
Structure determines behavior.
In an ordinary material, properties come from its atoms and bonds. In a metamaterial, they come from a designed repeating unit. The geometry of the building block, repeated in a precise lattice, is what produces the property. Change the geometry, and you change the material, without changing the chemistry at all.
Properties that natural materials don’t have.
Classic examples include a negative refractive index (bending waves backward). In the mechanical world, metamaterials with a negative Poisson’s ratio, so-called auxetic materials, get fatter when you stretch them instead of thinner [6]. A negative index also underpins the “superlens”, an optic that could in principle resolve features smaller than the wavelength of light, long thought impossible [16]. Others can have near-zero or even negative stiffness, or absorb specific frequencies of sound or vibration.
Tunability.
Because the property lives in the geometry, it can be dialed in: stiff here, compliant there, gradient in between — across a single part. This programmability makes metamaterials so attractive for engineering the human body, where tissues vary continuously in their mechanical properties.
What is the relationship between metamaterials and 3D Printing?
The two are deeply intertwined because a metamaterial’s magic lives in microarchitecture that is often impossible to make any other way. Building thousands of precisely shaped, interconnected unit cells, sometimes at the scale of hundreds of microns, with internal features no drill or mold could reach, is exactly what additive manufacturing does well. In practice, 3D printing is the manufacturing method that made metamaterials real, and metamaterials are one of the most compelling reasons to print rather than machine [3].
That relationship has recently gained a fourth dimension. 4D printing produces metamaterials whose geometry changes over time in response to a stimulus (heat, moisture, light, or even acoustic waves), so a flat 3D-printed sheet can fold into a stent, or a scaffold can stiffen as tissue grows into it [4]. When the printed architecture is designed to interact with living cells, researchers increasingly call these structures meta-biomaterials: architected biomaterials whose geometry itself is the functional element [3].
Metamaterials in healthcare: current applications
This is where the field is moving fastest, and it deserves the spotlight. The common thread is control: the ability to program a material’s mechanical response down to specific regions of a single part is what makes metamaterials so powerful for interfacing with the human body.
A few of the most active areas:
Orthopedic and dental implants.
Solid titanium is far stiffer than bone . Ti-6Al-4V has an elastic modulus around 110 GPa, versus roughly 10–30 GPa for cortical bone and under 2 GPa for trabecular bone [10]. That mismatch causes stress shielding: the implant carries the load the bone should, and the surrounding bone weakens and resorbs. 3D-printed lattice and auxetic metamaterials let engineers lower and tune an implant’s effective stiffness toward that of the host bone, while porous architecture invites bone ingrowth for better fixation [2]. Because the same print run can also match a patient’s individual anatomy, the promise is an implant that is simultaneously stiffness-matched, better tolerated, and less likely to fail over a lifetime of loading.
Tissue-engineering scaffolds.
Architected and auxetic scaffolds don’t just hold cells. Their geometry provides mechanical cues that steer stem-cell differentiation down bone or cartilage pathways, a field known as mechanobiology [9]. Newer work uses acoustically responsive architected biomaterials to guide chondrogenic and osteogenic differentiation, aiming at hard-to-treat conditions like osteoarthritis [12].
Biodegradable implants and scaffolds.
Metamaterial architecture also gives designers control over how a temporary implant disappears. A printed scaffold can support healing tissue and then degrade at a rate set by its geometry as much as its chemistry, so the body gradually takes over the load without a second surgery to remove hardware.
Wearable, in-vitro, and implantable devices.
Mechanical metamaterials are being designed into flexible sensors, conformal wearables, and soft implants [1] — a whole class of “mechanical metamaterials for bioengineering.”
Diagnostics and imaging.
Acoustic and electromagnetic metamaterials can sharpen sensitivity in ultrasound and other sensing modalities, enabling smaller, more precise diagnostic devices. Printed sensors built on metamaterial structures can track physiological parameters with higher sensitivity and specificity than a conventional sensor of the same size [19].
Soft surgical robotics.
Metamaterial structures give soft robots programmable flexibility and shape change, useful for minimally invasive tools that must navigate delicate anatomy [13].
The frontier, and the catch
Metamaterials are a genuine new frontier in materials science, and 3D printing is the key that unlocks them. But turning a striking lattice into an approved medical device is its own challenge: a geometry-defined, load-bearing material has to prove it fatigues and performs predictably [11], batch after batch, in terms a regulator can evaluate. That is the harder, less glamorous work of turning a printed structure into a regulator-legible material system. Much of the real progress over the next few years will happen here. A second reason to get fluent in this now: the narrow palette of qualified printing materials is one of the real constraints on healthcare 3D printing, and metamaterials offer a way around it—designing the property you need rather than waiting for a material that happens to have it [15]. (See our companion piece, “Regulator-Legible Material Systems.”)
If you want to go deeper on where architected meta-biomaterials are heading, this is exactly the terrain of 3DHEALS’ “Biomaterials Frontier for 3D Printing” virtual event — where speaker Ebrahim Yarali (MERLN Institute, Maastricht University) presents his work on auxetic, acoustic-responsive architected biomaterials for skeletal regeneration [12]. Details and free registration [8]: https://3dheals.com/biomaterials-frontier/.
References :
1. Kazim, M., Pal, A., & Goswami, D. Mechanical Metamaterials for Bioengineering: In Vitro, Wearable, and Implantable Applications. Advanced Engineering Materials, 2025;27(7):2401806. https://advanced.onlinelibrary.wiley.com/doi/10.1002/adem.202401806
2. Shirzad, M., Zolfagharian, A., Bodaghi, M., & Nam, S.Y. Auxetic metamaterials for bone-implanted medical devices: recent advances and new perspectives. European Journal of Mechanics – A/Solids, 2023;98:104905. https://www.sciencedirect.com/science/article/abs/pii/S0997753822003357
3. Zadpoor, A.A. Meta-biomaterials. Biomaterials Science, 2020;8(1):18–38. https://pubmed.ncbi.nlm.nih.gov/31626248/
4. Alanazi, B.N., Ahmed, H.A., Alharbi, N.S., Ebrahim, N.A.A., & Soliman, S.M.A. Exploring 4D printing of smart materials for regenerative medicine applications. RSC Advances, 2025;15(39):32155–32171. https://pmc.ncbi.nlm.nih.gov/articles/PMC12412672/
5. Veselago, V. The electrodynamics of substances with simultaneously negative values of ε and μ. Soviet Physics Uspekhi, 1968 (orig. 1967). https://iopscience.iop.org/article/10.1070/PU1968v010n04ABEH003699
6. Kolken, H.M.A., & Zadpoor, A.A. Auxetic mechanical metamaterials. RSC Advances, 2017;7:5111–5129. https://doi.org/10.1039/C6RA27333E
7. Ziolkowski, R.W. Metamaterials: the early years in the USA. EPJ Applied Metamaterials, 2014. https://epjam.edp-open.org/articles/epjam/full_html/2014/01/epjam140003/epjam140003.html
8. 3DHEALS — Biomaterials Frontier for 3D Printing (virtual event, Sept 10, 2026). https://3dheals.com/biomaterials-frontier/
9. Yarali, E., Zadpoor, A.A., Staufer, U., Accardo, A., & Mirzaali, M.J. Auxeticity as a Mechanobiological Tool to Create Meta-Biomaterials. ACS Applied Bio Materials, 2023;6(7):2562–2575. https://doi.org/10.1021/acsabm.3c00145
10. Reimagining Orthopaedic Implants: Mechanobiochemical Innovations to Overcome Stress Shielding (review of implant–bone modulus mismatch and stress shielding). https://www.sciencedirect.com/science/article/pii/S0079642526000290
11. Zadpoor, A.A. Mechanical performance of additively manufactured meta-biomaterials. Acta Biomaterialia, 2019;85:41–59. https://doi.org/10.1016/j.actbio.2018.12.038
12. Ebrahim Yarali — researcher profile, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University. https://merlninstitute.com/discover-merln/find-a-merln-member/ebrahim-yarali
13. Zheng, X., Jiang, Y., Mete, M., Li, J., Watanabe, I., Yamada, T., & Paik, J. Metamaterial robotics. Science Robotics, 2025;10(108):eadx1519. https://doi.org/10.1126/scirobotics.adx1519
14. Interview with Dr. Jeong Hun Park: Auxetics for Soft Tissue Engineering. 3DHEALS. https://3dheals.com/interview-with-dr-jeong-hun-park-auxetics-for-soft-tissue-engineering/
Related Links:
Regulator-Legible Material Systems: The Real Frontier in 3D-Printed Biomaterials
3D Printing & Biofabrication For Breast Reconstruction (On Demand, 2024)
3DHEALS Biomaterials 2024 (On Demand, 2024)
Interview with Dr. Jeong Hun Park: Auxetics For Soft Tissue Engineering
Interview with Julien Payen: Lattice Medical
Interview Dr. Mohit Chhaya: BellaSeno
Interview with Esther Valliant: Bioglass for 3D Printing
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