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A multiplexed FRET aptasensor for simultaneous detection of mycotoxins with magnetically controlled graphene oxide/Fe3O4 as single energy acceptor?
摘要： Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are the most common mycotoxins and often coexist in agricultural products, which are known to be a toxic superposition and even carcinogenic effects on humans. We proposed a multiplexed fluorescence resonance energy transfer (FRET) aptasensor for simultaneous detection of mycotoxins with magnetically controlled graphene oxide (GO)/Fe3O4 as single energy acceptor. CdTe quantum dots emitting green (GQDs) and red (RQDs) fluorescence are modified by aptamers specifically for AFB1 and FB1 and used as dual energy donors. Compared with conventional FRET system based on GO quencher, GO/Fe3O4, a single energy acceptor, can not only quench the fluorescence of aptamer-modified GQDs and RQDs with different emission peaks simultaneously, but also be removed by effective magnetic separation to eliminate the interference of background. In the absence of GO/Fe3O4 nanocomposites, the aptamer modified GQDs and RQDs give off strong fluorescence under ultraviolet radiation. The fluorescence of GQDs and RQDs is quenched when GO/Fe3O4 nanocomposites is added to the system owing to the π–π stacking interaction between GO/Fe3O4 nanocomposites and GQDs- and RQDs-labeled aptamer. However, in the presence of AFB1 and FB1, the binding of aptamers to their specific targets will fold their single stranded structures and hinder the contact between base group in aptamers and GO/Fe3O4, which cause the fluorescence recovery of GQDs and RQDs. With the help of one step of magnetic separation, the supernatants can be collected for fluorescence analysis. After optimization of detection conditions, the developed method had a wider linear range of 10 pg mL?1–100 ng mL?1 for AFB1 and 50 pg mL?1–300 ng mL?1 for FB1 and showed no cross-reactivity with other closely related mycotoxins, respectively. The limit of detection for AFB1 and FB1 are calculated to be 6.7 and 16.2 pg mL?1 based on S/N=3. The detection of mycotoxins has been successfully realized in peanut samples and a new application field of FRET system is expected for various targets.
关键词： aptasensor,fluorescence resonance energy transfer,aflatoxin B1,fumonisin B1,simultaneous detection
更新于2025-09-11 14:15:04
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Molecularly imprinted photoelectrochemical sensor for fumonisin B1 based on GO-CdS heterojunction
摘要： A rapid and ultrasensitive molecularly imprinted photoelectrochemical (MIP-PEC) sensing platform based on ITO electrode modified with GO-CdS heterojunction was prepared for ultrasensitive measure of fumonisin B1 (FB1). CdS quantum dots (QDs) were combined with a suitable amount of graphene oxide (GO) to form a heterojunction to enhance signal response with accurately calculating energy levels (VB/CB or HOMO/LUMO). The MIP-PEC sensor was successful fabricated after MIP was immobilized on the electrode with the basis of these results. In the phosphate buffer solution (PBS), it was clearly observed that the non-elution MIP-PEC sensor had almost no photocurrent response, which was due to the slower electron transfer speed. When the MIP-PEC sensor is eluted in ethanol, its photocurrent response was significantly restored, that was because the fact that the template molecules were washed away, and electron donors entered the holes and accelerated the electron transfer. Its photocurrent response was reduced because of holes blocked when the MIP-PEC sensor was hatched in the template molecules culture fluid. This phenomenon fully showed that the MIP-PEC sensor can specifically detect the target. Thus, The work has a linear range from 0.01 to 1000 ng mL?1 with a detection limit of 4.7 pg mL?1 for FB1. Furthermore, the fabricated MIP-PEC sensor will confirm the actual application.
关键词： Photoelectrochemical sensor,Molecularly imprinted polymer,fumonisin B1,GO-CdS heterojunction
更新于2025-09-09 09:28:46