MXene catalytic amplification-fluorescence/absorption dimode aptamer sensor for the detection of trace Pb2+ in milk

Abstract

Lead ion (Pb2+) is a toxic heavy metal, which is very harmful to organisms. Therefore, the establishment of a rapid, simple, and sensitive method is of great significance to food safety and human health. It was found that MXeneTi3C2 nanosheet (NS) has a strong catalytic effect on the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) via H2O2 to form the oxidized product (TMBOX); it has a strong fluorescence peak at 415 nm and an absorption (Abs) peak at 295 nm. The aptamer of Pb2+ (Aptpb) can be adsorbed on the surface of an NS to form MXene-Apt conjugates, which reduces its catalytic active sites and inhibits its catalytic activity. When the target Pb2+ is added, it specifically binds with Aptpb to release MXene NSs to enhance the dimode signals. Therefore, a new MXene catalytic fluorescence/absorption dimode aptamer biosenering platform was fabricated for the determination of trace Pb2+ in milk and water samples, with the fluorescence assay linear range (LR) of 5.0 × 10−2-2.0 nmol/L.

Advances in MXene-based luminescence sensing strategies

“…2). 34 In this work, it was discovered that Mxene Ti 3 C 2 nanosheets could effectively catalyze the oxidation reaction of 3,3,5,5-tetramethylbenzidine (TMB) to obtain TMBOX (the oxidation product of TMB). TMBOX showed an UV absorption peak at 295 nm and a strong fluorescence emission peak at 415 nm.…”

A fluorescence aptamer sensor utilizing WS2 nanosheets for sensitive detection of patulin: enhanced specificity and wide applicability

“…24,25 Aptamers offer versatility in functionalization and engineering, facilitating various signaling methods like colorimetric, uorometric, and electrochemical detections in devices known as aptasensors. [26][27][28] FL aptasensors, in particular, are modied with uorescent materials to achieve a specic spatial conguration that can bind or sense targets, leading to changes in FL intensity useful for target assays. 29,30 Cy3 is a cyanine dye with well-separated excitation bands, high sensitivity to the surroundings, and high energy transfer efficiency, making it a perfect choice for excitonic coupling experiments and uorescent labeling use.…”

Highly catalytic nanoenzyme of covalent organic framework loaded starch- surface-enhanced Raman scattering/absorption bi-mode peptide as biosensor for ultratrace determination of cadmium

“…They also have a high affinity for many metal ions and have become excellent receptors for use in methodologies which exploit molecular recognition chemistry. Among them, absorption, fluorescence and electrochemical methods are used frequently in chemical analysis ( 1 , 2 ). Zhuang et al ( 3 ) reported a peptide fluorescent probe TP-2 (TPE-TrP-Pro-GlN-His-Glu-NH 2 ), which utilized an aggregation-induced emission effect and afforded high selectivity in the determination of Hg 2+ , the detection limit (DL) being 41 nM.…”