Development of an Au/ZnO thin film surface plasmon resonance-based biosensor immunoassay for the detection of carbohydrate antigen 15‐3 in human saliva

► Au/ZnO thin film SPR sensor showed linear response to saliva CA15-3 concentration. ► Non-specific protein binding might decrease sensitivity for the Biacore SPR system. ► Au/ZnO SPR has better resolution in detecting low saliva CA15-3 concentration.