Flash and Bone

Flexible, sticky and adaptable, cells are the ultimate building blocks – forming lifelong structures during development, or moulding into shape inside wounds. Helping this process along, bioengineers make tiny scaffolds to guide cells while they knit together. But making their structures biocompatible – welcoming to cells and tissues – is a challenge. Here researchers use a technique called two-photon polymerisation, aiming precise laser blasts inside a wobbly hydrogel. Chemicals inside react to each flash of light and harden into patterns, allowing the team to create structures like this model femur (grey). They find a balance between biocompatibility, so the structures attract living cells, and photo reactivity, allowing precise design. The sight of human cells (highlighted in turquoise with nuclei in purple) swarming over the femur, raises hopes for similar tiny structures helping with injuries in the future.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Image from work by Wanwan Qiu and colleagues
• Institute for Biomechanics, ETH Zurich, Swtizerland
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Advanced Materials, January 2026