Abstract
In this work, we have developed a simple and rapid colorimetric assay for the detection of immunoglobulin E (IgE) using functional nucleic acids (FNAs) and a solid-phase competition enzyme-linked immunosorbent assay (ELISA). The FNAs including aptamer of recombinant IgE, G-quadruplex and its complementary fragments were immobilized on 96-well microplates to achieve recognition and detection of IgE in biological samples. The G-quadruplex DNAzyme catalyzed 2,2′-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS)-hemin-H2O2 system was used to improve the sensitivity of colorimetric assay. In the presence of IgE, the hairpin structure and G-quadruplex would be destroyed, resulting in the inactivation of DNAzyme and subsequent reduction of its absorbance. This cost-effective approach detected IgE in the linear range from 5.0 pg/mL to 500 ng/mL, with the limit of detection (LOD) of 2.0 pg/mL, under optimal conditions. Moreover, the developed method was successfully applied to the rapid detection of IgE in human urine, indicating a great potentiality of this approach in clinical diagnosis and other biomedical applications.
Highlights
Proteins, the natural biomolecules, often serve as biosignaling molecules, molecular indicators, and biomarkers
We hypothesized that the formation of a stable hairpin structure based on the aptamer of immunoglobulin E (IgE), G-quadruplex and its partial complementary sequence could be efficiently used for aptamer of IgE, G-quadruplex and its partial complementary sequence could be efficiently used for detection of protein (Figure 1A)
These results indicated that the proposal is feasible, and structures were destroyed. These results indicated that the proposal is feasible, and the designed functional nucleic nucleic acid acid (FNA) the designed FNAs include G-quadruplex fragments that can be effectively used for the include G-quadruplex fragments that can be effectively used for the determination of IgE
Summary
The natural biomolecules, often serve as biosignaling molecules, molecular indicators, and biomarkers. Several traditional immunoassays, such as enzyme immunoassay [1], fluoroimmunoassay [2], chemiluminescence immunoassay [3], lateral-flow assay [4], and protein microarrays [5], are commonly used for protein detection. These techniques rely on ELISA and antibody specificity. Most of these approaches suffer from several shortcomings, such as lack of robustness and variable stability of the employed antigens
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