A research team led by Professor JIANG Changlong from Hefei Institutes of Physical Science of the Chinese Academy of Sciences, has developed an innovative real-time multi-scenario fluorescence detection technology for monitoring methylglyoxal.

The team designed and fabricated a sensor by embedding upconversion optical probes into three-dimensional porous hydrogels. This sensor, integrated with the color recognition capabilities of a smartphone, enables rapid and on-site detection of methylglyoxal.

"That means that in the future your phone can help save the flavor of your wine and keep an eye on your health," said KANG Xiaohui, a member of the team.

Their findings have been published in Analytical Chemistry.

Methylglyoxal is a dicarbonyl compound found in both wine fermentation and human metabolism. In wine, excessive methylglyoxal can result in undesirable flavors, such as astringency, while in humans, elevated concentrations are linked to an increased risk of diabetes. Therefore, developing reliable real-time methods to monitor its concentration is important for both wine quality and diabetes management.

Three-dimensional hydrogels are known for their stretchability and biocompatibility. However, many fluorescent hydrogels suffer from interference due to autofluorescence and background noise, which limits their effectiveness in biological applications.

In this study, the researchers utilized upconversion nanoparticles (UCNPs), which help eliminate background fluorescence interference and significantly enhance detection sensitivity.

The hydrogel sensor developed by the research team is based on a probe made from UCNPs and modified eosin B (mEB), operating through a fluorescence resonance energy transfer (FRET) mechanism. When methylglyoxal interacts with mEB, the upconversion fluorescence shifts from red to green, allowing for precise detection. 

Researchers embedded the probe in a hydrogel, and employed 3D printing technology to create a portable and reversible fluorescent sensor.

The results demonstrated that the detection limits (LOD) for the upconversion fluorescent probe and the hydrogel sensor were 59 nM and 75.4 nM, respectively.

This sensing patch offers an innovative and effective solution for flavor standardization in wine production and for health monitoring in diabetes patients, according to the team.

Figure 1. Design and fabrication of the hydrogel sensing patch based on upconversion probes and its sensing response mechanism. (Image by KANG Xiaohui)

Figure 2. Reversible detection of methylglyoxal using the hydrogel sensing patch. (Image by KANG Xiaohui)