期刊
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
卷 267, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.saa.2021.120618
关键词
Bacillus cereus; Aptamer; Up-conversion nanoparticles; Magnetic separation; Food
类别
资金
- National Natural Science Foundation of China [31972154, 31901772]
- China Postdoctoral Science Foundation [2019M651748]
A sensitive luminescent bioassay for the detection of Bacillus cereus (B. cereus) was established using up-conversion fluorescence and magnetic separation technology. The method showed good quantitative ability and high specificity for B. cereus, with good reproducibility and stability.
A sensitive luminescent bioassay for the detection of Bacillus cereus (B. cereus), a common bacterium, harmful to human health, was established based on up-conversion fluorescence and magnetic separation technology. Herein, aptamers (Apt) are modified on the surface of magnetic nanoparticles (MNPs) to form Apt-MNPs capture probes. The aptamer complementary strands (cDNA) are connected to upconversion nanoparticles (UCNPs) to form UCNPs-cDNA signal probes. In the absence of analyte, the UCNPs-cDNA-Apt-MNPs complex will be formed due to the specific binding between the aptamer and the complementary strand. In the presence of B. cereus, the amount of free UCNPs-cDNA increased in the system, which ultimately increased the fluorescence intensity of the solution. Hence, when the UCNPs-cDNA-Apt-MNPs system was excited by a 980 nm near-infrared light, a decrease in the fluorescence of the complex was observed at 548 nm due to the detachment of UCNPs-cDNA. Therefore, based on this principle, the calibration curve is constructed between the concentration of the analyte (B. cereus) and the fluorescence intensity. The results show that the method has a good quantitative ability for B. cereus in the range of 49-49 x 106 cfu/mL under the optimal conditions with a detection limit of 22 cfu/mL. Moreover, the proposed detection method also exhibits a high degree of specificity. The spiked recovery rate of the actual sample was in the range of 90.54%-111.28%, with good relative standard deviation values (2.12%-3.13%), indicating that the method has good reproducibility and stability. This study demonstrates that the constructed method can be used successfully for the rapid detection of B. cereus in food. (C)& nbsp;2021 Elsevier B.V. All rights reserved.
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