Label‐free Electrochemical Impedance Detection of Rotavirus Based on Immobilized Antibodies on Gold Sononanoparticles

Currently, rotaviruses (RVs) are the leading cause of severe childhood gastroenteritis worldwide. This study proposes a sensitive and simple label-free assay for determining rotaviruses using, for the first time, electrochemical impedance spectroscopy (EIS). The immunosensor is fabricated by self-assembled monolayers (SAMs) of cysteamine on gold sononanoparticles (AuSNPs) modified glassy carbon electrode. The electron transfer resistance (Ret) of the electrode interface was adopted as a parameter for the detection of rotavirus. Using the proposed immunosensor, a good linear relationship (r2=0.993) between impedance change and logarithmic value of rotaviruses in a wide range of 4.6 to 4.6×104 PFU mL−1 was found, with a low limit of detection (LOD) 2.3 PFU mL−1 and a total analysis time of 55 min. Working parameters of the immunosensor, such as pH, antibodies concentration and immune-reaction time, have been investigated and optimized. No obvious interferences from non-target viruses such as hepatitis A virus (HAV) and enterovirus were found. In addition, the electrochemical impedance immunosensor has exhibited good sensitivity, selectivity and stability.