title: A reusable aptamer-based evanescent wave all-fiber biosensor for highly sensitive detection of Ochratoxin A.
abstract: Although aptamer-based biosensors have attracted ever-increasing attentions and found potential applications in a wide range of areas, they usually adopted the assay protocol of immobilizing DNA probe (e.g., aptamer, aptamer-complementary oligonucleotides) on a solid sensing surface, making it critical and challengeable to keep the integration of nucleic acid surface during the regeneration and the restoration to its original DNA probe form after repeated uses. In order to address the issue, we report a novel aptamer-based biosensing strategy based on an evanescent wave all-fiber (EWA) platform. In a simple target capturing step using aptamer-functionalized magnetic microbeads, signal probes conjugated with streptavidin are released and further detected by a EWA biosensor via a facial dethiobiotin-streptavidin recognition. Apart from the inherent advantages of aptamer-based evanescent wave biosensors (e.g. target versatility, sensitivity, selectivity and portability), the proposed strategy exhibits a high stability and remarkable reusability over other aptasensors. Under the optimized conditions, the typical calibration curve obtained for Ochratoxin A has a detection limit of 3nM with a linear response ranging from 6nM to 500nM. The dethiobiotin-streptavidin sensing surface instead of the traditional nucleic acid one can be reused for over 300 times without losing sensitivity.
authors.affiliation: School of environment, Tsinghua University, Beijing 100084, China.
authors.forename: Ruoyu
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Tsinghua University, Beijing 100084, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xiang
authors.affiliation: School of environment, Tsinghua University, Beijing 100084, China. Electronic address: xhzhou@mail.tsinghua.edu.cn.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhou
authors.affiliation: School of environment, Tsinghua University, Beijing 100084, China.
authors.forename: Lan-Hua
authors.initials: LH
authors.lastname: Liu
authors.affiliation: School of environment, Tsinghua University, Beijing 100084, China.
authors.forename: Hanchang
authors.initials: H
authors.lastname: Shi
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D001483:Base Sequence; D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D005336:Fiber Optic Technology / Q000295:instrumentation; D057230:Limit of Detection; D009183:Mycotoxins / Q000032:analysis*; D009793:Ochratoxins / Q000032:analysis*; D055100:Optical Fibers
chemical_list: D052157:Aptamers, Nucleotide; D009183:Mycotoxins; D009793:Ochratoxins; C025589:ochratoxin A
keywords: Aptamer; Evanescent wave; Ochratoxin A; Optical fiber biosensor; Reusability