Effective label-free biosensing system for food allergy diagnostics: comparative detection of standard Ige with ImmunoCAP

Food allergy is a common disease worldwide with over 6% of the population (200-250 million people) suffering from any food allergy nowadays. The most dramatic increase seems to be happening in children and young people. Therefore, improvement in the diagnosis efficiency of these diseases are needed. Immunoglobulin type E (IgE) biomarker determination in human serum is a typical in vitro test for allergy identification. In this work we used a novel biosensor based on label-free photonic transducers called BICELLs (Biophotonic Sensing Cells) for IgE detection. These BICELLs have a thin film of nitrocellulose over the sensing surface, they can be vertical optically interrogated and are suitable for being integrated on-a-chip. The BICELLs sizes used were 100 and 800 µm of diameter. Calibration curves were obtained with IgE standards, by immobilizating anti-IgE antibodies and recognizing with standard IgE calibrators. The results, in similar assay format, were compared with commercial-available ImmunoCAP. The versatility of the interferometric nitrocellulose-based sensing surface was demonstrated since the limit of detections for BICELLs and ImmunoCAP were 0.7 and 0.35 kU/L, respectively.