title: A homogeneous and "off-on" fluorescence aptamer-based assay for chloramphenicol using vesicle quantum dot-gold colloid composite probes.
abstract: In this work, a novel homogeneous and signal "off-on" aptamer based fluorescence assay was successfully developed to detect chloramphenicol (CAP) residues in food based on the fluorescence resonance energy transfer (FRET). The vesicle nanotracer was prepared through labeling single stranded DNA binding protein (SSB) on limposome-CdSe/ZnS quantum dot (SSB/L-QD) complexes. It was worth mentioning that the signal tracer (SSB/L-QD) with vesicle shape, which was fabricated being encapsulated with a number of quantum dots and SSB. The nanotracer has excellent signal amplification effects. The vesicle composite probe was formed by combining aptamer labeled nano-gold (Au-Apt) and SSB/L-QD. Which based on SSB's specific affinity towards aptamer. This probe can't emit fluoresce which is in "off" state because the signal from SSB/L-QD as donor can be quenched by the Au-aptas acceptor. When CAP was added in the composite probe solution, the aptamer on the Au-Apt can be preferentially bounded with CAP then release from the composite probe, which can turn the "off" signal of SSB/L-QD tracer into "on" state. The assay indicates excellent linear response to CAP from 0.001 nM to 10 nM and detection limit down to 0.3 pM. The vesicle probes with size of 88 nm have strong signal amplification. Because a larger number of QDs can be labeled inside the double phosphorus lipid membrane. Besides, it was employed to detect CAP residues in the milk samples with results being agreed well with those from ELISA, verifying its accuracy and reliability.
authors.affiliation: State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China.
authors.forename: Yang-Bao
authors.initials: YB
authors.lastname: Miao
authors.affiliation: Key Laboratory of Asymmetric Synthesis and Chirotechnology of Sichuan Province, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, PR China; University of Chinese Academy of Sciences, Beijing 10049, PR China.
authors.forename: Hong-Xia
authors.initials: HX
authors.lastname: Ren
authors.affiliation: State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China. Electronic address: ganning@nbu.edu.cn.
authors.forename: Ning
authors.initials: N
authors.lastname: Gan
authors.affiliation: State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China.
authors.forename: You
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China. Electronic address: caoyuting@nbu.edu.cn.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Cao
authors.affiliation: State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo 315211, PR China.
authors.forename: Tianhua
authors.initials: T
authors.lastname: Li
authors.affiliation: Faculty of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing 210000, PR China.
authors.forename: Yinji
authors.initials: Y
authors.lastname: Chen
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry; D002701:Chloramphenicol / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D017979:Gold Colloid / Q000737:chemistry*; D057230:Limit of Detection; D008081:Liposomes / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry*; D018036:Selenium Compounds / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D052157:Aptamers, Nucleotide; D019187:Cadmium Compounds; D017979:Gold Colloid; D008081:Liposomes; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; D002701:Chloramphenicol; C058667:cadmium selenide; C031238:zinc sulfide
keywords: Chloramphenicol; Fluorescence aptasensor; Homogeneous assay; Off–on; liposome−quantum dot