A team of researchers from Hefei Institutes of Physical Science of the Chinese Academy of Sciences has developed a fluorescence detection technology for monitoring methylglyoxal — which is a dicarbonyl compound found in both wine fermentation and human metabolism.

To develop the technology, the researchers built a sensor by embedding upconversion optical probes into three-dimensional porous hydrogels. The resulting sensor, imbued with the color-recognition capabilities of a smartphone, allows for quick, on-site detection of methylglyoxal.

Source: Kang Xiaohui

The team explained that in wine, excessive amounts of methylglyoxal can produce undesirable flavors — like astringency. Meanwhile, in humans, elevated concentrations of methylglyoxal are associated with an increased risk of diabetes. As such, the technology promises to be important for both wine quality and diabetes management.

While three-dimensional hydrogels are known for their stretchability and biocompatibility, many fluorescent hydrogels encounter interference due to autofluorescence and background noise, thereby limiting their effectiveness in biological applications.

To remedy this, the team used upconversion nanoparticles (UCNPs) to help eliminate background fluorescence interference and also enhance detection sensitivity.

The researchers created the hydrogel sensor using a probe composed of UCNPs and modified eosin B (mEB), which operates based on fluorescence resonance energy transfer (FRET). Upon interaction with methylglyoxal, the mEB causes the upconversion fluorescence to shift from red to green, thus enabling precise detection. The probe was embedded in a hydrogel, and 3D printing technology was used to create a portable and reversible fluorescent sensor. The results revealed that the detection limits for the upconversion fluorescent probe and the hydrogel sensor were 59 nM and 75.4 nM, respectively. According to the team, this sensing patch offers an effective approach for flavor standardization in wine production and health monitoring for diabetes patients.

The findings are detailed in the article, “Visual Detection of Methylglyoxal in Multiple Scenarios via NIR-Excitable Reversible Ratiometric Fluorescent Hydrogel Sensor,” which appears in the journal Analytical Chemistry.