In-Vitro Allergy Detection Using A Silver Nanoparticle Modified Nanostructured Biosensor

IgE (Immunoglobulin E) in the serum of an asthma patient is a useful index for allergy diseases. In this study, a nanostructured biosensor having uniformly deposited gold nanoparticles (GNPs) as the sensing electrode was used for fast and low serum consuming detection of the IgE in allergy patients' serum. To enhance the charge transferring efficiency of the biosensor, silver nanoparticles (SNPs) were deposited on the GNP layer. The group 2 allergen, Der p2, was used as the probe to detect IgE. To ensure the specificity of detection, the affinity purified goat anti-Human IgE antibody was further immobilized to the IgE. After immobilizing the anti-IgE on the sensor, the electrochemical impedance spectroscopy (EIS) analysis was implemented to examine the concentration of the target IgE in terms of a Nyquist plot. Blood serum samples with known allergy levels detected by the commercially available ImmunoCAP were used for the verification of the sensor. It is observed that the difference of the charge transfer resistance (Delta R-et) 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 patient's allergy level with low sample consumption, short sample preparation time, and quick processing.