Application of photonic crystal enhanced fluorescence to detection of low serum concentrations of human IgE antibodies specific for a purified cat allergen (Fel D1)

Abstract

We demonstrate the detection of low concentrations of allergen-specific Immunoglobulin E (IgE) in human sera using a Photonic Crystal Enhanced Fluorescence (PCEF) microarray platform. The Photonic Crystal (PC) surface, designed to provide optical resonances for the excitation wavelength and emission wavelength of Cy5, was used to amplify the fluorescence signal intensity measured from a multiplexed allergen microarray. Surface-based sandwich immunoassays were used to detect and quantify specific IgE antibodies against a highly purified cat allergen (Fel d1). A comparison of the lowest detectable concentration of IgE measured by the PC microarray system and a commercially available clinical analyzer demonstrated that the PCEF microarray system provides higher sensitivity. The PCEF system was able to detect low concentrations of specific IgE (~0.02 kU/L), which is 5 to 17 -fold more sensitive than the commercially available FDA-approved analyzers. In preliminary experiments using multi-allergen arrays, we demonstrate selective simultaneous detection of IgE antibodies to multiple allergens.

Photonic crystals: emerging biosensors and their promise for point-of-care applications

“…PC structures have gained significant attention as sensitive transducers and have been incorporated into biosensors that capture, detect, and quantify various biological molecules, such as pathogens, 7,47,91–96 DNA, 97–101 proteins, enzymes, 102,103 glucose, 42,104–106 cells, 107,108 toxins, 109 and allergens. 110 …”

“…110,179,180 PC structures can enhance fluorescence signals when the optical resonance of the PC surface overlaps with either the excitation or emission spectra of a fluorophore. This enhanced excitation and emission yielded ~7500-fold increase in fluorescence signals.…”

“…181 In a recent study, a PC-enhanced fluorescence (PCEF) microarray platform was used to detect low concentrations of IgE in human sera with a limit of detection of 0.02 kU L −1 , which was comparable to current blood-based IgE detection methods. 110 However, current PC-based allergen platforms rely on fluorescence detection, which limits their use at the POC due to the requirements for labeling, additional instrumentation, and multiple assay preparation steps.…”

A selective and sensitive nanosensor for fluorescent detection of specific IgEs to purified allergens in human serum

“…24,25 Recently, nanomaterials have increasingly been used for food allergy detection. [27][28][29][30] Although the detection limit for the application of photonic crystal enhanced uorescence toward detection of sIgE is very low (0.048 ng mL À1 ), 30 the detection procedures are cumbersome, and substantial, expensive equipment is required, which limit its clinical application. Gold nanoclusters as uorescent labels for the determination of total IgE is more convenient and simple, however, the detection limit is 0.2 ng mL À1 which does not provide adequate levels of sensitivity, and the test results do not suggest which allergen may be mediating the allergic reaction.…”

Portable organic gas detection sensor based on the effect of guided-mode resonance

“…[4][5][6][7] Recent years, optical detection methods based on the effect of guided-mode resonance are often used in biological testing. For example, optical devices combined with micro-nano structures based on this theory have been used in cancer detection, 8,9 serum concentrations of human IgE antibodies detection, 10 and live cell adhesion imaging. [11][12][13] In addition to these biological applications, guided-mode resonance methods can also be used to measure the refractive index of solutions.…”