A fluorescent sensor based on single band bright red luminescent core-shell UCNPs for the high-sensitivity detection of glucose and glutathione.

As the reliable biomarkers to evaluate the diabetes and neurological disease, sensitive and accurate detection of glucose and glutathione (GSH) in biological samples is necessary for early precaution and diagnosis of related-diseases. The single red upconversion nanoparticles (UCNPs) especially with core-shell structure can penetrate deeper biological tissues and cause less energy loss and thus have higher sensitivity and accuracy. Additionally, an enzyme-controlled cascade signal amplification (ECSAm) strategy will further enhance sensitivity. Herein, using single red UCNPs with core-shell structure as the luminescent material, a fluorescent sensor based on ECSAm was developed for the highly sensitive and accurate detection of glucose and GSH. Under the optimal conditions, the limits of detection for glucose and GSH by fluorescent method were 0.03 μM and 0.075 μM, separately. This assay was used to analyze the content of glucose and GSH in serum samples, and the obtained data was close to that of commercial blood glucose and GSH detection kit. The developed sensor platform based on single red UCNPs with core-shell structure and ECSAm can be a promising method for the accurate and sensitive detection of glucose and GSH in biological samples.