Sensitive Detection of Chloramphenicol Based on Fluorescence Resonance Energy System by Upconversion Nanoparticles Aptamer Sensor
In this study,hydrophilic rare earth-doped upconversion nanoparticles(UCNPs)and gold nanoparticles(AuNPs)were used as donors and acceptors of fluorescent energy,respectively.Based on the fluorescence resonance energy transfer(FRET)system,an aptamer sensor to detect chloramphenicol(CAP)was established.The results showed that UCNPs had strong emission at 547 nm under excitation at 980 nm.AuNPs were prepared by the trisodium citrate reduction method and an obvious absorption peak appeared at 519 nm.UCNPs were connected to chloramphenicol aptamers through the streptavidin-biotin amplification system to form fluorescent donor probes(UCNPs-apt),and AuNPs were linked to the sulfhydryl-modified chloramphenicol complementary chains to form fluorescent acceptor probes(AuNPs-cDNA).Due to the complementary base pairing of aptamer and cDNA,the distance between UCNPs-apt and AuNPs-cDNA was narrowed.At this time,the FRET phenomenon resulted in the fluorescence quenching of UCNPs and partial fluorescence recovery after CAP was added.Under the optimal detection conditions,the CAP concentration had a good linear relationship with the fluorescence recovery value.The detection range was 0.01-10 ng/mL,and the detection limit was 5 pg/mL.This method was used to carry out recovery experiments on milk samples.The recovery rate was 93.5％-99.4％,and the relative standard deviation was 1.18％-2.84％.The method indicated simple,highly selective and sensitive,minimal autofluorescence,rather low interference background characteristics.
Upconversion nanoparticlesGold nanoparticlesFluorescence resonance energy transferChloramphenicolAptamer
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