Polyphenol briged bimetallic-heterostructure inducing chiral peroxidase nanozyme activity for enantiomers identification in gastric cancer

D -alanine ( D -Ala) and D -proline( D -Pro) levels dramatically increase in the bio-fluids of gastric cancer (GC) patients, which are suggested to be potential biomarkers associated with GC. Therefore, monitoring the concentrations of D -Pro and D -Ala in the body fluids of GC patients is of great significance. In this study, a highly sensitive Surface Enhanced Raman Scattering (SERS) sensor has constructed based on bimetallic heterostructure nanoenzyme (3-MPBA: Co-TA@Ag NPs) for D -AAs detection in GC bio-fluids. Attributing to the formation of Ag-Co bimetallic dual active centers, the electron transfer behaviors accelerated boron hydroxyl group ionization in neutral pH, as well as the ultra-robust hydroxyl alcohol esterification reaction occurred between D -Ala and D -Pro and 3-MPBA. By simply testing different absorbance intensities at various concentrations and sample, a sensor for noninvasive detection of D -Pro/Ala is constructed with good specificity and efficiency. Besides, the quantitative determination of D -Pro/Ala (limits of detection (LOD) 2.37 μM and 2.15 μM for D -Pro/Ala. Furthermore, based on the differential level of D -Pro/Ala in GC bio-fluids, the differentiation of saliva samples with D -Pro/Ala can also be implemented by the proposed method, showing great potential in GC diagnosis.