An aptamer-based fluorescence probe for facile detection of lipopolysaccharide in drinks

Abstract

Bacterial toxin contamination is a serious food safety issue. Rapid, facile detection of bacterial toxins in food is crucial to control their harmful effects on human health. In this study, a facile, selective, and cost-effective method with a 6-carboxy-X-rhodamine labeled lipopolysaccharide binding aptamer (ROX-LBA)/GO fluorescent probe was developed based on the specific recognition characteristics of aptamers and the super fluorescence quenching efficiency of graphene oxide (GO) and used for the detection of lipopolysaccharides (LPS). ROX-LBA is adsorbed on the GO surface because of its strong p-p stacking interactions in the flexible single-stranded state, and fluorescence is quenched by GO via Förster resonance energy transfer (FRET). After adding LPS, the aptamer binds to LPS and forms a LPS/ROX-LBA complex, which exhibits weak binding affinity with GO. ROX-LBA cannot effectively combine with GO, and fluorescence is restored. The concentration of LPS can be quantitatively analyzed by observing fluorescence changes in the sensing system. The fluorescence intensity proportionally increases with LPS concentration (25-1600 ng mL À1 ), and the detection limit is 15.7 ng mL À1 . Hence, the proposed method provides an alternative strategy for the specific detection of endotoxin in drink samples (e.g., apple juice and beer) and could be widely applied to quantify various bacterial toxins by replacing the aptamer sequences.

Aptamer-based biosensors for the diagnosis of sepsis

“…Also, there were some studies using aptamers labeled with 6-carboxyfluorescein (6-FAM) to detect LPS. For instance, Zhang et al designed a 6-FAM labeled aptamer as a fluorescent probe to detect LPS, by combining the advantages of the aptamer's specific binding ability and the fluorescence quenching effect of GO [ 58 ]. However, the linear range of this probe for LPS was 25–1600 ng/mL and the lower LOD was 15.7 ng/mL.…”

“…Some cross-reactivity towards the unspiked human serum [ 56 , 60 , 65 , 67 ] Fluorescence quenching efficiency The concentration of LPS can be quantitatively analyzed by observing fluorescence changes Little consumption of sample. Low recovery of serum sample [ 58 , 59 ] Field-Effect Transistor-Based Approach The graphene surface immobilized aptamer is unfolded without IL-6 and it would fold after binding with the target. These aptamer structural changes bring the negative charges in IL-6 to the proximity of the graphene-liquid interface Low-voltage operation (< 1 V), inherent gain amplification, biocompatibility and miniaturization [ 63 , 64 ] Electrochemical Electrochemical sensors are constructed using various nanomaterials Gold disk electrodes: Short detection time and little cross-interaction reactivity to plasmid DNA, RNA, proteins, saccharides, and/or lipids which are most likely to coexist with LPS assay Gra AuNPs: Overcome the disadvantage of limited nicking endonuclease recognition and integrate molecular biological technology and nano-biotechnology with electrochemical detection to cascade signal amplification, which can detect target LPS down to the femtogram level Gold atomic cluster: Simple sensor fabrication compared with other electrochemical sensors for LPS RGO/AuNPs: Short LPS detection time within 35 min.…”

A rapid aptamer‐based fluorescence assay for the detection of lipopolysaccharides using SYBR Green I

“…A few groups have utilized the fluorescence quenching property of graphene oxide (GO) and reduced graphene oxide (rGO) for this purpose. [11] In this technique, the aptamers are labelled with fluorescent reporter probes. The reporter probes experience quenching when the aptamer binds to GO or rGO.…”

Aptamer-Based Biosensing with a Cationic AIEgen

“…[17] Indeed, quite a few aptamer-based fluorescent sensors have been described. [8,16,[18][19][20][21] However, these sensors generally incorporate conventional dyes that are vulnerable to fluorescence quenching when they form aggregates at overly high concentration. This phenomenon, known as 'aggregationcaused quenching' (ACQ), is a notorious issue that restricts the usefulness of conventional dyes in biomolecular applications.…”