Determination of avian influenza A (H9N2) virions by inductively coupled plasma mass spectrometry based magnetic immunoassay with gold nanoparticles labeling

Avian influenza viruses are the pathogens of global poultry epidemics, and may even cause the human infections. Here, we proposed a novel inductively coupled plasma mass spectrometry (ICP-MS) based immunoassay with gold nanoparticles (Au NPs) labeling for the determination of H9N2 virions. Magnetic-beads modified with anti-influenza A H9N2 hemagglutinin mono-antibody (mAb-HA) were utilized for the capture of H9N2 virions in complex matrix; and Au NPs conjugated with mAb-HA were employed for the specific labeling of H9N2 virions for subsequent ICP-MS detection. With a sandwich immunoassay strategy, this method exhibited a high specificity for H9N2 among other influenza A virions such as H1N1 and H3N2. Under the optimized conditions, this method could detect as low as 0.63   ng   mL −   1 H9N2 virions with the linear range of 2–400   ng   mL −   1 , the relative standard deviation for seven replicate detections of H9N2 virions was 7.2% (c   =   10   ng   mL −   1 ). The developed method was applied for the detection of H9N2 virions in real-world chicken dung samples, and the recovery for the spiking samples was 91.4–116.9%. This method is simple, rapid, sensitive, selective, reliable and has a good application potential for virions detection in real-world samples.