Rapid fluorescence detection of immunoglobulin E using an aptamer switch based on a binding-induced pyrene excimer

Abstract

Immunoglobulin E (IgE) is an important immunoglobulin related to allergic reactions and some diseases such as atopic dermatitis, allergic asthma, etc. Sensitive and rapid detection of IgE is desired for disease diagnosis and therapeutics. Taking advantage of a binding-induced pyrene excimer, we developed a sensitive fluorescent aptamer switch for IgE sensing by using a pyrene-labeled aptamer. The aptamer having four base pairs at the stem was labeled with a single pyrene molecule at the 3 0 end and 5' end and used as an affinity probe. The binding of IgE brought the pyrene moiety at each terminal of the aptamer into proximity, generating an excimer and showing a distinct fluorescence peak. The measurement of the fluorescence peak of the excimer allowed the sensitive detection of IgE. We optimized the experimental conditions such as temperature, incubation time, and metal cations. The detection limit for IgE was about 1.6 nM. This assay displayed good specificity and allowed for the detection of IgE spiked in a diluted human serum sample. This fluorescent aptamer sensor has potential for its application in rapid sensing of IgE.

[2]Catenanes Displaying Switchable Gin-Trap-Like Motion

“…Pyrene and its excimer have long been applied to provide fluorescence outputs in response to changes in distance associated with altered molecular structures . Accordingly, we synthesized [2]­catenane 19 , an analogue of 1 , in the hope that its “folded” and “linear” conformations, with significant changes induced in the positions of the two m -xylyl rings, would be reported by the fluorescence signals of the pyrene side arms (Scheme ).…”

Recent Advances in Excimer-Based Fluorescence Probes for Biological Applications

“…Human immunoglobulin E (lgE) plays a pivotal role in various allergic reactions. Bai and co-workers [ 36 ] used pyrene ( 3 ) as fluorophore ( Figure 7 ) for lgE sensing. A aptamer-based probe was constructed with four base pairs at the stem to which pyrene was labeled at the 3′ and 5′ end, respectively ( Figure 8 ).…”

“… ( A ) The fluorescence spectra of the probe IgE-4bp-2Py (50 nM) in the absence and the presence of IgE (50 nM). ( B ) The fluorescence intensity (485 nm) at different concentrations of IgE [ 36 ]. …”

Aptamers against Immunoglobulins: Design, Selection and Bioanalytical Applications

“…The method can be multiplexed using different fluorophores with non-overlapping emission peaks, providing a robust, simple and high-throughput option [136]. Molecular Light Switch Complex 100-800 100 [128] Fluorescence enhancement using a DNA aptamer 92-37,000 57 [130] Amplification through allostery-triggered enzymatic recycling amplification NA 5 [131] Fluorescent oligonucleotide probe based on G-quadruplex scaffold for signal-on ultrasensitive protein assay 4.72-7560 0.095 [132] Fluorescence anisotropy 1000-60,000 350 [133] Fluorescence anisotropy assay NA 20 [134] Fluorescence protection assay 100-50,000 100 [136] Aptamer-barcode-based assay based on instantaneous derivatization chemiluminescence coupled to magnetic beads 4.88-20,000 4.6 [137] Competitive fluorescence quenching assay 350-35,000 170 [138] Rapid fluorescence detection of immunoglobulin E using an aptamer switch based on a binding-induced pyrene excimer NA 1600 [139] 6.1.…”