title: A regeneratable, label-free, localized surface plasmon resonance (LSPR) aptasensor for the detection of ochratoxin A.
abstract: Binding of an analyte on the surface of a nanoparticle typically promotes a change in the local refractive index, which gives rise to a shift in the wavelength of the localized surface plasmon resonance (LSPR) absorption band. The magnitude of the LSPR wavelength change is dependent on both the location of the analyte relative to the surface of the nanoparticle and the degree of alteration of the refractive index. We have employed this phenomenon as the basis for designing a new, label-free approach for the detection of the toxic mold mycotoxin, ochratoxin A (OTA) that employs a gold nanorod (GNR) and an aptamer target binding mechanism. In this system, binding of OTA causes an accumulation of OTA and G-quadruplex structure of the aptamer. This process results in a longitudinal wavelength shift of the LSPR peak associated with a change in the local refractive index near the GNR surface. By using this method, OTA can be quantitatively detected at concentrations lower than 1 nM. In addition, the results of this effort show that aptamer functionalized GNR substrate is robust in that it can be regenerated for reuse over seven times by heating in methanol at 70 °C to remove OTA. Moreover, the proposed biosensor system exhibits high selectivity for OTA over other mycotoxins. Finally, the sensor can be employed to detect OTA in ground corn samples with excellent recovery levels.
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Gwangju 500-712, Republic of Korea.
authors.forename: Jin-Ho
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Gwangju 500-712, Republic of Korea.
authors.forename: Ju-Young
authors.initials: JY
authors.lastname: Byun
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Gwangju 500-712, Republic of Korea.
authors.forename: Hyoyoung
authors.initials: H
authors.lastname: Mun
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Gwangju 500-712, Republic of Korea.
authors.forename: Won-Bo
authors.initials: WB
authors.lastname: Shim
authors.affiliation: Immune Therapy Research Center, Korea Research Institute of Bioscience & Biotechnology (KRIBB), 125 Gwahak-ro, Yuseong-gu, Daejeon 305-806, Republic of Korea.
authors.forename: Yong-Beom
authors.initials: YB
authors.lastname: Shin
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Gwangju 500-712, Republic of Korea.
authors.forename: Taihua
authors.initials: T
authors.lastname: Li
authors.affiliation: Department of Chemistry, School of Physics and Chemistry, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Gwangju 500-712, Republic of Korea; Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Gwangju 500-712, Republic of Korea. Electronic address: mkim@gist.ac.kr.
authors.forename: Min-Gon
authors.initials: MG
authors.lastname: Kim
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D009183:Mycotoxins / Q000032:analysis*; D043942:Nanotubes / Q000737:chemistry*; D009793:Ochratoxins / Q000032:analysis*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D003313:Zea mays / Q000737:chemistry / Q000382:microbiology
chemical_list: D052157:Aptamers, Nucleotide; D009183:Mycotoxins; D009793:Ochratoxins; C025589:ochratoxin A; D006046:Gold
keywords: Aptamer; Gold nanorod; Label-free detection; Localized surface plasmon resonance; Ochratoxin A; Small molecule