Detection of Helicobacter pylori (H. pylori) Cytoplasmic Protein (ureB) in Wastewater using an Electrochemical Competitive Immunosensor

Due to the almost-complete dependence on clinical diagnosis, current Helicobacter pylori (H. pylori) epidemiological statistics suffer from fragmented geographical coverage and lagged data updating worldwide. Acquiring information based on the quantitative detection of biomarkers from domestic wastewater provides a promising way for the future H. pylori epidemiological study. Here, we report wastewater-adapted electrochemical competitive immunosensor (WECI). This method focuses explicitly on detecting H. pylori cytoplasmic ureB in wastewater and contains a series of designs to overcome the challenges brought by the complicated analytical matrix. The developed WECI achieved a practical detection range from 10 pg mL $^{-{1}}$ to 5.0 ng mL $^{-{1}}$ ( ${R}^{{2}}$ = 0.996) and showed the corresponding limit of detection (LoD) and limit of quantification (LoQ) of 0.37 and 1.4 pg mL $^{-{1}}$ , respectively. It can be prepared within 6 h and kept highly sensitive for at least six weeks. When testing real wastewater samples, WECI resulted in an average biomarkers recovery rate of 70.9%, which was remarkably higher than the average of 47.0% achieved using qPCR, indicating the excellent applicability toward actual wastewater detection. Our reported WECI is the first study to quantitatively detect H. pylori ureB from wastewater, opening up new vistas for H. pylori epidemiological study.