A Highly Sensitive Aptamer-Nanogold Catalytic Resonance Scattering Spectral Assay for Melamine

Abstract

The aptamer (ssDNA) was used to label nanogold (NG) particle to fabricate an aptamer-nanogold (NGssDNA) probe for melamine. The probe was stabile in pH 6.6 Na(2)HPO(4)-NaH(2)PO(4) buffer solutions and in the presence of high concentration of electrolyte. Upon addition of melamine, it interacted with the probe to form big NGssDNA-melamine aggregations that led to the resonance Rayleigh scattering (RRS) intensity at 566 nm increased greatly. The increased RRS intensity (ΔI) is linear to melamine concentration in the range of 1.89-81.98 μg/L, with a detection limit of 0.98 μg/L melamine. The unreacted probe in the aptamer reaction solution exhibited strong catalytic effect on the slow Cu(2)O particle reaction between glucose and Fehling reagent, but the catalytic activity of NG aggregations is very weak. When melamine concentration increased, the unreacted probe decreased, the RRS peak intensity at 614 nm decreased. The decreased RS intensity is linear to melamine concentration in the range of 0.63-47.30 ng/L melamine, with a detection limit of 0.38 ng/L. The aptamer-modified nanogold catalytic RRS assay was applied to determination of melamine in milk, with high sensitivity and selectivity, simplicity and rapidity.

Current Advances and Prospects on Implementation of Highly Sensitive Aptamer-based Dual System for Melamine Detection: New Promising Tool of Great Affinity

“…For MA detection, the most commonly used aptamers are in form of poly-Ts aptamer (ssDNA) with purified sequence 5'TTTT TTTTTTTTTTTTTTTTTTTTTTTTTTT [58]. Yun et al used the selected MA aptamer 5′-TTTTTTTTTTTTTTTTTTTT-3' to detect melamine in milk sample.…”

“…The increase of MA decreases the unreacted NGssDNA and the RRS intensity decrease linearly accompanied by color changes from red to blue. While using this method in MA detection, the results ranged between 1.89-81.89 µg/l with LOD 0.98 µg/l determined by the NGssDNA probe [58]. For label free MA aptasensor, the AuNPs are incubated with anti-MA aptamer for 15 min followed by purification using centrifugation at 10,000 rpm for 5 min to obtain the aptamer-protected AuNPs.…”

“…This method is based on competitive recognition of bisphenol with immobilized aptamer fixedon the surface of the electrode. MA detection in milk using ssDNA aptamer with sequence of 5'-TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT-3' [58] is highly effective. Aptamer detection and identification for various harmful microorganisms in clinical practice such as Pseudomonas sp.…”

“…Aptamer, nanoparticle or aptamer-modified NPs showed efficiency in detection of MA in food or beverages with a sensitivity of 1.89-81.89 µg/l and 0.98 µg/l in short time [58]. However, AuNPs by SERS showed the concentration range of 0.31-5.0 mg/l in milk with a limit of detection of 0.17 mg/l within 30 min by improving time of detection but its LOD is of anxiety.…”

A facile and sensitive peptide-modulating graphene oxide nanoribbon catalytic nanoplasmon analytical platform for human chorionic gonadotropin

“…Wang et al 9 used Cu 2+ -ion-modified graphene oxide (GO) nanoparticles as a heterogeneous catalyst mimicking functions of horseradish peroxidase (HRP), and a simple colorimetric method was proposed to detect 30-140 μM ascorbic acid. 10 Our research group has established some sensitive resonance Rayleigh scattering (RRS) and surface enhanced Raman scattering methods for rapid detection of melamine, 11 PDGF 12 and Cu, 13 based on the nanoparticle probe aggregation and catalysis. Graphene oxide nanoribbons (GONRs) were prepared by using the method of facile unzipping of nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs) with the help of microwave energy, 14,15 which exhibited good water solubility and has been used in nanoanalysis.…”