Development of a multifunctional fluorescent probe for smartphone-assisted detection of formaldehyde in food in 100% aqueous solution and diabetic models.

Formaldehyde (FA), a biological metabolic intermediate, poses severe health risks, including carcinogenicity, cardiovascular disease, and neurological disorders, upon excessive accumulation. Its illicit use as a food preservative exacerbates public health risks, necessitating efficient detection methods for food safety. To tackle the drawbacks of existing techniques and existing fluorescent probes, such as poor aqueous solubility, we developed a naphthalimide-based fluorescent probe (FYY) for FA detection in 100% aqueous solution. The probe exhibits excellent stability, rapid kinetics (5 min), a low detection limit (1.92 μM), and outstanding resistance to interferences. When integrated with a smartphone platform, it allows portable, on-site FA quantification in food samples. Method validation demonstrated high accuracy, with relative standard deviations (RSDs) below 3.97%. Furthermore, probe FYY was also successfully used to image both exogenous and endogenous FA in HeLa cells. By establishing a diabetic cell model, we observed elevated FA concentrations, indicating a possible connection between FA and metabolic dysregulation in diabetes. This work not only provides a flexible tool for FA detection in biomedical research but also establishes a practical platform for food safety monitoring and health diagnostics.