’Tis the season for eerie-looking experiments: check out these uncannily ocular copper dendrites growing inside a hydrogel scaffold. Dhruv Bhandari, currently a master’s student in materials science at Cornell University, captured the image when he was a research intern at the Swiss Federal Institute of Technology, Lausanne (EPFL), this past summer. There, he worked on 3D-printing metals using a technique called vat photopolymerization. The process begins with a 3D-printed polymer gel scaffold, which is then infused with metal ions. Exposing the ions to a reductant—sodium borohydride in this case—causes the metal to start precipitating within the gel. Once the composite is finished growing, it’s heated to remove the polymer, leaving behind the pure metal. The EPFL team published a paper about its printing technique in September (Adv. Mater. 2025, DOI: 10.1002/adma.202504951).
Submitted by Dhruv Bhandari
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Brianna Barbu Brianna Barbu is a physical sciences reporter at C&EN. Bri is a DC-based science reporter covering organic chemistry and related topics. She also makes up 1/3 of C&EN’s structures team and is a regular contributor to the Chemsitry in Pictures blog and Newscripts. Bri studied chemistry and creative writing at Hope College and earned a master’s degree in organic materials chemistry from the University of Michigan in 2019 before escaping the lab to pursue a career in journalism. Prior to joining C&EN, she was a 2021 AAAS Mass Media fellow at Discover magazine. When she’s not contemplating the weird world of carbon-based molecules, Bri enjoys swimming, crocheting, reading novels with her cat, and playing D&D.
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