Detection of allergies using a silver nanoparticle modified nanostructured biosensor

The IgE (Immunoglobulin E) in the serum of an asthma patient is a useful index for the detection of allergy diseases. In this study, a nanostructured biosensor with uniformly deposited gold nanoparticles (GNPs) is used as the sensing electrode for fast and low serum consuming detection of the IgE in an allergy patientʹs serum. To enhance the charge transfer efficiency of the biosensor, silver nanoparticles (SNPs) were deposited on the GNP layer. The group 2 allergen, Der p2, was used to indicate IgE. To ensure the specificity of detection, affinity purified goat anti-human IgE antibody was further immobilized to the IgE. After immobilizing the anti-IgE, electrochemical impedance spectroscopy (EIS) analysis was implemented to examine the concentration of the target IgE which was displayed in terms of a Nyquist plot. Blood serum samples with known allergy levels detected by the commercially available ImmunoCAP were used for verification of the sensor results. It is observed that the difference in the charge transfer resistance (ΔRet) between the Der p2 immobilized electrode and the anti-IgE bonded electrode for each individual serum sample closely correlates to its ImmunoCAP class. The blood serum detection results indicate that the presented nanostructured biosensor is able to detect a patientʹs allergy level with low sample consumption, short sample preparation time, and quick processing.