Cerium oxide mimetic enzyme based colorimetric detection of potential oesophageal cancer biomarkers

Oesophageal cancer (OC) is a prevalent malignant tumor that poses a significant threat to individuals. Current mainstream detection method is endoscopy, which requires professional operators and expensive instruments. Therefore, it is crucial to develop a rapid, easy-to-operate, and low-cost detection method. In this study, an RNA colorimetric biosensor was successfully constructed using cerium oxide mimetic enzyme. The sensor is constructed on 96-well plates, which are immobilized with DNA-RNA-DNA complexes in microtiter wells when target RNA is present. This immobilization is based on the principle of base complementary pairing. The CeO₂ immobilized has the unique advantage of catalyzing the bluing of 3,3',5,5'-tetramethylbenzidine (TMB) directly without the need any additional oxidant in microtiter wells. This property allows for the detection of RNA and enables the visualization of multiple sample assays. Furthermore, the RNA colorimetric sensor demonstrates good selectivity, immunity to interference, and high stability. Under optimal conditions, the sensor exhibited linearity in the range of 10^-13 to 10^-9 M with a detection limit of 33.26 fM. Therefore, this study presents a new detection method for oesophageal cancer screening.