Injectable and self-healable glowing hydrogel achieves ultra-sensitive detection of formaldehyde

Researchers from the Institute of Polymer Science and Engineering at National Taiwan University have developed a multifunctional hydrogel sensor for detecting formaldehyde.

Detecting volatile organic compounds (VOCs) is important for protecting both the environment and human health. Recently, researchers at National Taiwan University have created a new type of glowing (luminescent) hydrogel that can detect VOCs with high sensitivity. The study is published in Small.

These special hydrogels are made from a flexible material network combining modified gelatin and a sugar-based compound (PG/PDA). Surface-modified europium-containing laponite particles (Eu³⁺(TTA)@Lap) are added into this PG/PDA network to give the hydrogels their glowing and sensing properties.

The hydrogels glow differently when they are exposed to specific VOCs, creating unique light patterns that reveal which compounds are present. In particular, the PG/PDA/Eu³⁺(TTA)@Lap hydrogel shows outstanding ability to detect formaldehyde, a common air pollutant, with a detection limit as low as 39 parts per billion (ppb), which is much lower than the World Health Organization’s safe limit of 80 ppb.

This high sensitivity comes from an “antenna effect,” where the added organic compound helps the europium ions glow more strongly.

In addition to their sensing performance, the hydrogels can heal themselves after damage and can be injected into various shapes or environments, making them highly adaptable.

Overall, this innovative glowing hydrogel system offers a powerful and flexible platform for detecting formaldehyde and other harmful VOCs.

“This injectable and self-healable hydrogel sensor opens new possibilities for safer, long-term environmental monitoring,” says Prof. Yi-Cheun Yeh, corresponding author of the study.