Responsive photonic hydrogel for colorimetric detection of formaldehyde

Formaldehyde (FA) can damage DNA, cause liver and kidney dysfunction, and ultimately lead to malignant tumors. Therefore, it is essential to develop a method that can conveniently detect FA with high detection sensitivity. Here, a responsive photonic hydrogel was prepared by embedding three-dimensional photonic crystal (PC) into amino-functionalized hydrogel to construct a colorimetric sensing film for FA. The amino groups on the polymer chains of the photonic hydrogel reacts with FA to increase the crosslinking density of the hydrogel, resulting in its volume shrinkage and a decrease in microsphere spacing of the PC. That causes the reflectance spectra blue-shift of more than 160 nm and color change from red to cyan for the optimized photonic hydrogel, achieving the sensitive, selective and colorimetric detection of FA. The constructed photonic hydrogel shows good accuracy and reliability for practical determination of FA in air and aquatic products, providing a new strategy for designing other target analytes responsive photonic hydrogels.

Automated summary

A responsive photonic hydrogel was prepared by embedding a three-dimensional photonic crystal into an amino-functionalized hydrogel, enabling colorimetric detection of formaldehyde (FA). When the hydrogel reacts with FA, it undergoes volume shrinkage and a decrease in microsphere spacing, resulting in a blue shift in reflectance spectra and a color change from red to cyan. This photonic hydrogel shows high sensitivity, selectivity, and accuracy for detecting FA in air and aquatic products, providing a new approach for designing responsive photonic hydrogels for other target analytes.