3D printing has already transformed how we build—from customized prosthetics to space-ready tools. But researchers at École Polytechnique Fédérale de Lausanne (EPFL) have now taken the technology to an entirely new level. Their pioneering method doesn’t just print—it grows metals and ceramics from inside a simple water-based gel, leading to materials that are both incredibly dense and structurally intricate.
This could redefine the future of energy devices, biomedical implants, and high-precision sensors—applications where strength, lightness, and complexity are crucial.
The Problem with Traditional 3D Printing
Most 3D printing methods rely on vat photopolymerization—a process where liquid resin is selectively hardened by light. While great for creating precise shapes, it’s mostly limited to polymers—not metals or ceramics.
Scientists have tried converting printed polymers into metal or ceramic structures later, but these methods often lead to porous, weak, and shrunken materials. The shrinkage can warp parts, and the porosity drastically reduces their mechanical strength—making them unsuitable for high-performance applications.
The EPFL Breakthrough: Growing Metals Inside Hydrogels
Led by Dr. Daryl Yee, the team at EPFL’s Laboratory for the Chemistry of Materials and Manufacturing tackled this issue with a creative twist. Instead of infusing metal precursors before printing, they flip the process entirely.
Here’s how it works:
- Step 1: Print a Hydrogel Scaffold
A hydrogel—a soft, water-based gel—is 3D printed into any desired shape. Think of it as a blank sponge ready to soak up metals. - Step 2: Infuse with Metal Salts
The printed hydrogel is then soaked in a solution of metal salts (like iron, copper, or silver). - Step 3: Chemical Transformation
These metal salts are chemically converted into metal nanoparticles that spread throughout the hydrogel. - Step 4: Repeat the Process
The infusion can be repeated 5–10 times to achieve very high metal concentrations. - Step 5: Heat and Finalize
A final heating step burns away the hydrogel, leaving behind a dense, metallic or ceramic structure in the same shape as the original gel.
The result? A solid, high-density material—as intricate as the printed hydrogel, but far stronger and more compact than anything produced by earlier techniques.
Strength that Redefines Limits
To test their innovation, the researchers created mathematical lattice structures called gyroids using iron, silver, and copper. These shapes are known for their complex, interwoven geometries that balance strength and lightness—perfect for testing this new material’s capabilities.
The results were striking:
- The gyroids could withstand 20 times more pressure than those made with traditional methods.
- Shrinkage dropped dramatically—from 60–90% down to just 20%.
In essence, these new materials are not only stronger but also retain their shape and precision far better than before.
Why This Matters
The implications are vast. The method’s ability to create strong, lightweight, and complex 3D architectures makes it ideal for:
- Biomedical implants – durable yet biocompatible devices.
- Energy conversion systems – metallic catalysts and electrodes for efficient chemical-to-electrical energy transformations.
- Sensors and microdevices – intricate geometries for detecting environmental or biological signals.
- Cooling and energy systems – high-surface-area metals for heat management in advanced technologies.
It also introduces a revolutionary concept in additive manufacturing:
Material selection happens after printing, not before.
This means one hydrogel design could potentially be transformed into different materials (iron, silver, ceramics, etc.)—a level of flexibility unheard of in 3D printing so far.
Looking Ahead: Automation and Industry Applications
The only challenge? Time.
Each infusion cycle takes a while, making the process slower than other 3D printing-to-metal methods. But the EPFL team is already on it—developing robotic automation to speed up the repetitive steps.
Their next goal is to increase density even further and make the method more industry-ready. Once perfected, this could become the foundation for a new generation of manufacturing—where complex metal and ceramic components are grown, not built.
A Step Toward the Future of Manufacturing
From soft gels to ultra-strong metals, this research represents a remarkable leap in materials science. It’s not just about creating stronger 3D-printed objects—it’s about rethinking how materials are formed at the most fundamental level.
As Dr. Yee aptly summarizes:
“Our work not only enables high-quality metals and ceramics with an accessible, low-cost 3D printing process; it also introduces a new paradigm—where material selection occurs after 3D printing, rather than before.”
With such innovation, the line between printing and growing is beginning to blur—and the next industrial revolution might just be born from water and light.
Source: Ecole Polytechnique Fédérale de Lausanne (EPFL) – Advanced Materials, 2025