Inner filter effect regulated upconversion sensing platform for non-invasive detection of two gastric cancer relevant substances.

Gastric cancer is the fifth most common cancer in the world. The concentrations of D-Pro and D-Ala in the saliva of patients with early gastric cancer were significantly higher than those of healthy people. Urease has also been found to be closely associated with gastric cancer. Therefore, monitoring the concentration of D-amino acids and urease is of great significance for the diagnosis and treatment of gastric cancer. In this study, multi-peak emission UCNPs (ES-UCNPs) was synthesized based on emulsion self-assembly strategy. Polyethylenimine (PEI) modified copper-based Prussian blue analogues (PEI-CuFc) exhibit enhanced the stability and peroxidase-like catalytic activity. And we developed a colorimetric-luminescent dual-mode sensing platform for two gastric cancer relevant substances by utilizing PEI-CuFc nanozymes to regulate the luminescence spectrum through IFE mechanism. Notably, besides serving as the foundation for emulsion self-assembly, sodium dodecyl sulfate (SDS) effectively improved the catalytic activity of PEI-CuFc, significantly amplifying the detectable signal and thereby enhancing assay sensitivity. To our knowledge, this study presents the first report of simultaneous detection of these two gastric cancer relevant substances in a single assay. The detection limits fall within the clinically relevant concentration range of early gastric cancer biomarkers, offering a promising approach for non-invasive early diagnosis of gastric cancer.