Palladium Nanoparticles-Based Fluorescence Resonance Energy Transfer Aptasensor for Highly Sensitive Detection of Aflatoxin M1 in Milk

Abstract

A highly sensitive aptasensor for aflatoxin M1 (AFM1) detection was constructed based on fluorescence resonance energy transfer (FRET) between 5-carboxyfluorescein (FAM) and palladium nanoparticles (PdNPs). PdNPs (33 nm) were synthesized through a seed-mediated growth method and exhibited broad and strong absorption in the whole ultraviolet-visible (UV-Vis) range. The strong coordination interaction between nitrogen functional groups of the AFM1 aptamer and PdNPs brought FAM and PdNPs in close proximity, which resulted in the fluorescence quenching of FAM to a maximum extent of 95%. The non-specific fluorescence quenching caused by PdNPs towards fluorescein was negligible. After the introduction of AFM1 into the FAM-AFM1 aptamer-PdNPs FRET system, the AFM1 aptamer preferentially combined with AFM1 accompanied by conformational change, which greatly weakened the coordination interaction between the AFM1 aptamer and PdNPs. Thus, fluorescence recovery of FAM was observed and a linear relationship between the fluorescence recovery and the concentration of AFM1 was obtained in the range of 5–150 pg/mL in aqueous buffer with the detection limit of 1.5 pg/mL. AFM1 detection was also realized in milk samples with a linear detection range from 6 pg/mL to 150 pg/mL. The highly sensitive FRET aptasensor with simple configuration shows promising prospect in detecting a variety of food contaminants.

Occurrence and analysis of mycotoxins in domestic Chinese herbal medicines

“…Since then, this group has proposed another accurate fluorescent sensing method for the determination of AFB 1 in grape juice and human serum samples based on a hairpin structure of a G-quadruplex oligonucleotide-aptamer chimera (Taghdisi et al 2018 ). A highly sensitive aptasensor utilising the fluorescence resonance energy transfer for AFM 1 detection in milk samples was recently developed (Li et al 2017a ). Another group established a surface plasmon resonance (SPR) method using an SPR sensor chip for simultaneous detection of AFB 1 , OTA, ZEN, and DON in corn (Wei et al 2019 ).…”

Aptasensors for mycotoxins in foods: Recent advances and future trends

“…The detection was carried out by 3 steps within 40 min, displaying an LOD of 4.5 ppb in real rice seed samples. In addition, large PdNPs with strong absorption covering the whole UV‐Vis spectrum were introduced as the fluorescence quencher to construct a FL aptasensor for AFM 1 determination based on FRET between FAM and PdNPs (Li, Yang, et al., 2017). The close proximity of PdNPs and FAM resulted from the strong coordination reaction between PdNPs and nitrogen groups of aptamers could cause 95% fluorescence quenching of FAM, which was recovered upon the binding of target AFM 1 to the specific aptamers, exhibiting a linear detection range of 5–150 pg/ml and an LOD of 1.5 pg/ml for AFM 1 .…”

Photosensitizer Modulated Turn – off Fluorescence System and Molecular Logic Functions for Selective Detection of Arsenic (III)

“…[23][24][25][26] Recent synthetic advancements have led to the fabrication of nanorange materials with desired dimensions and topological features. [27][28][29][30][31] The metal surface with larger aspect ratio and anisotropic structural features shows relatively higher folds of enhancements in intensity. [32,33] However, in order to develop a selective fluorimetric sensor for detecting heavy metal ion, even more sensitive optical device needs to be designed.…”

“…The radiative and non radiative energy transfer depends on separation of fluorophore from metal surface and structural orientation of colloidal particles in relation to the oscillating dipole [23–26] . Recent synthetic advancements have led to the fabrication of nanorange materials with desired dimensions and topological features [27–31] . The metal surface with larger aspect ratio and anisotropic structural features shows relatively higher folds of enhancements in intensity [32,33] .…”