A dual-signal electrochemical immunosensor for the detection of HPV16 E6 oncoprotein based on PdBP dendritic ternary nanospheres and MBSi-Chi nanocomposites

Abstract

Cervical cancer is a common cancer in women. HPV16 E6 oncoprotein is a reliable biomarker for cervical cancer. Although there are other methods for detecting E6 oncoprotein, the electrochemical method has more advantages, such as low cost, convenience and speed. In this study, a novel dual-signal electrochemical immunosensor for quick and sensitive detection of E6 oncoprotein based on a high efficiency catalyst and signal label was developed. Herein, to achieve quick detection, palladium–boron–phosphorus dendritic ternary nanospheres (PdBP NSs) not only acted as a catalyst to catalyze H₂O₂, but also as a support material to capture antibodies. Moreover, to realize sensitive detection, nanocomposites of mesoporous silica nanoparticles loaded with methylene blue and coated with chitosan (MBSi-Chi) were synthesized as a signal label, which can produce electrochemical signal. Under optimal conditions, the label-free immunosensor exhibited a linear range of 100 fg mL⁻¹ to 4 ng mL⁻¹ with a detection limit of 72.8 fg mL⁻¹ (S/N = 3), and the sandwich-type immunosensor presented a linear range of 50 fg mL⁻¹ to 4 ng mL⁻¹ with a detection limit of 34.1 fg mL⁻¹ (S/N = 3). The as-prepared dual-signal immunosensor had desirable specificity, stability and repeatability, implying its potential applications in clinical laboratory.