title: Nanospherical Brush as Catalase Container for Enhancing the Detection Sensitivity of Competitive Plasmonic ELISA.
abstract: Plasmonic enzyme-linked immunosorbent assay (pELISA) based on catalase (CAT)-mediated gold nanoparticle growth shows great potential for the determination of disease-related biomarkers at ultralow concentrations by using sandwich formats. However, the relatively low sensitivity of this strategy using competitive formats limits its adoption for hapten detection. Herein, we present an improved competitive pELISA for ultrasensitive detection of ochratoxin A (OTA), where silica nanoparticles carrying poly(acrylic acid) brushes (SiO2@PAA) were used to decrease the affinity of competing antigens to anti-OTA monoclonal antibodies and amplify the signal as a "CAT container" (SiO2@PAA@CAT). The developed competitive pELISA exhibits extremely high sensitivity for OTA with detection limits of 10(-18) and 5 × 10(-20) g/mL by the naked eye and microplate reader, respectively. These values are at least 7 orders of magnitude lower than that of competitive CAT-based pELISA (10(-11) g/mL by the naked eye) and 8 orders of magnitude lower than that of horseradish peroxidase-based conventional ELISA (10(-11) g/mL by the microplate reader), respectively. Reliability and robustness of the proposed method were evaluated using actual agricultural products and human serum samples. This study demonstrated the potential of this modified method in practical applications involving the ultrasensitive detection of mycotoxins or other haptens.
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University , Nanchang 330047, P. R. China.|Jiangxi-OAI Joint Research Institute, Nanchang University , Nanchang 330047, P. R. China.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University , Nanchang 330047, P. R. China.|College of Life Science, Nanchang University , Nanchang 330031, P. R. China.|Jiangxi-OAI Joint Research Institute, Nanchang University , Nanchang 330047, P. R. China.
authors.forename: Rui
authors.initials: R
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University , Nanchang 330047, P. R. China.
authors.forename: Hengyi
authors.initials: H
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University , Nanchang 330047, P. R. China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Lai
authors.affiliation: State Key Laboratory of Food Science and Technology, Nanchang University , Nanchang 330047, P. R. China.|College of Life Science, Nanchang University , Nanchang 330031, P. R. China.|Jiangxi-OAI Joint Research Institute, Nanchang University , Nanchang 330047, P. R. China.
authors.forename: Yonghua
authors.initials: Y
authors.lastname: Xiong
mesh_terms: D002374:Catalase / Q000737:chemistry* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006046:Gold / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry; D015394:Molecular Structure; D009793:Ochratoxins / Q000032:analysis*
chemical_list: D009793:Ochratoxins; C025589:ochratoxin A; D006046:Gold; D002374:Catalase