A Novel Eosinophilia Diagnostics Using Label‐free Impedimetric Aptasensor for Soluble Interleukin‐5 Receptor Alpha

Abstract

Recently, interleukin‐5 receptor alpha (IL‐5RA) was reported to be a key surface molecule in the regulation of eosinophil proliferation. In this study, a highly sensitive aptamer for IL‐5RA was applied to an electrochemical biosensor. The rod‐shaped gold electrodes with circular gold surface were used. The aptasensor specifically detected membrane‐bound IL‐5RA on human eosinophils according to the number of the eosinophils. We further examined the usability of soluble IL‐5RA (sIL‐5RA) in the serum as a novel biomarker for the diagnosis of eosinophil‐related diseases. When eosinophilic inflammation occurs, the concentration of sIL‐5RA in the blood is highly elevated. To diagnose eosinophilic inflammation, the aptasensor was calibrated in phosphate‐buffered saline (PBS) to detect sIL‐5RA. The detection limit of the aptasensor in PBS was 1.69 pg/mL, which is lower than that of commercially available ELISA kits. The dynamic range of the aptasensor was 10–10,000 pg/mL, with high specificity over other serum proteins and interleukin family members. The aptasensor was capable of distinguishing between patients with eosinophilic asthma (EA) and normal controls (NCs) based on serum sIL‐5RA levels. Consequently, the fabricated aptasensor will contribute to the development of novel diagnostic systems for IL‐5RA‐related diseases.

Review—Interleukins Profiling for Biosensing Applications: Possibilities and the Future of Disease Detection

“…IL-5RA is a biomarker for eosinophilic inflammation and the concentration of sIL-5RA in blood in the case of eosinophilic inflammation is highly elevated. 200 For instance, Youn et al, Developed the aptasensor for IL-5RA utilizing rod-shaped gold electrodes with a circular gold surface. Its detection limit in PBS has been reported to be 1.69 pg mL −1 which is lower than ELISA kits available commercially.…”

Immobilization Techniques for Aptamers on Gold Electrodes for the Electrochemical Detection of Proteins: A Review

“…Here, gold nanoparticles were electrodeposited on the gold electrode in order to increase the electroactive area to obtain a higher aptamer-packing density and therefore an improved sensitivity. While the lysozyme aptasensor [61] showed significant interference from neutravidin and white wine, the aptasensor for interleukin-5 receptor alpha (IL-5RA) [62] demonstrated a drastic increase of the charge transfer resistance when tested with spiked serum.…”

“…The regeneration of the aptasensor can be realized by immersion in deionized water for 5 min at 95 °C . Nonspecific binding was tested with Youn et al [62] also investigated an AuNPs modified aptasensor for interleukin-5 receptor alpha (IL-5RA). It was composed of a 5 thiolated aptamer with a C 10 spacer that was immobilized on an AuNP modified gold electrode with subsequent backfilling of mercaptohexanol.…”

“…The aforementioned gold nanoparticles were obtained by the electrodeposition of HAuCl 4 from acidic solutions (6 mM HAuCl 4 and 100 mM KNO 3 [62], 1 mM HAuCl 4 and 0.5 M H 2 SO 4 [61,81]). If shape directing agents are used during the electrodeposition, shapes other than spheres can be obtained that exhibit a larger surface area and roughness.…”

Biosensors Made of Synthetic Functional Nucleic Acids Toward Better Human Health

“…To conclude the section on biosensors for noncancer biomarkers, it is noteworthy that biosensors were also developed for type 2 diabetes (vaspin, gHSA, HbA1c), Barrett’s esophagus (fractalkine), phenylketonuria ( l -phenylalanine), asthma/allergies, periodontal disease (ODAM), acute kidney injury (neutrophil gelatinase-associated lipocalin), and biomarkers for multiple diseases (tumor necrosis factor-α, lysozyme, C-reactive protein, cytochrome C, and interleukin-5 receptor alpha). Two remarkable studies described electrochemical aptasensors for continuous real-time measurement of drugs in human whole blood or in animals where the sensor was implanted directly in the circulatory system .…”