title: Magnetic nanobead-based immunoassay for the simultaneous detection of aflatoxin B1 and ochratoxin A using upconversion nanoparticles as multicolor labels.
abstract: A novel and sensitive immunoassay for the simultaneous detection of aflatoxin B(1) (AFB(1)) and ochratoxin A (OTA) in food samples was developed by using artificial antigen-modified magnetic nanoparticles (MNPs) as immunosensing probes and antibody functionalized upconversion nanoparticles (UCNPs) as signal probes. NaY(0.78)F(4):Yb(0.2), Tm(0.02) and NaY(0.28)F(4):Yb(0.7),Er(0.02) UCNPs were prepared and functionalized, respectively, with immobilized monoclonal anti-AFB(1) antibodies and anti-OTA antibodies as signal probes. Based on a competitive immunoassay format, the detection limit for both AFB(1) and OTA under optimal conditions was as low as 0.01 ng mL(-1), and the effective detection range was from 0.01 to 10 ng mL(-1). The proposed method was successfully applied to measure AFB(1) and OTA in naturally contaminated maize samples and compared to a commercially available ELISA method. The high sensitivity and selectivity of this method is due to the magnetic separation and concentration effect of the MNPs, the high sensitivity of the UCNPs, and the different emission lines of Yb/Tm and Yb/Er doped NaYF(4) UCNPs excited by 980 nm laser. Multicolor UCNPs have the potential to be used in other applications for detecting toxins in the field of food safety and other fields.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.
authors.forename: Shijia
authors.initials: S
authors.lastname: Wu
authors.forename: Nuo
authors.initials: N
authors.lastname: Duan
authors.forename: Changqing
authors.initials: C
authors.lastname: Zhu
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Ma
authors.forename: Miao
authors.initials: M
authors.lastname: Wang
authors.forename: Zhouping
authors.initials: Z
authors.lastname: Wang
mesh_terms: D016604:Aflatoxin B1 / Q000032:analysis*; D015374:Biosensing Techniques / Q000295:instrumentation*; D002273:Carcinogens / Q000032:analysis; D003124:Colorimetry / Q000295:instrumentation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis*; D007118:Immunoassay / Q000295:instrumentation*; D018189:Immunomagnetic Separation / Q000295:instrumentation*; D009793:Ochratoxins / Q000032:analysis*; D013194:Staining and Labeling
chemical_list: D002273:Carcinogens; D009793:Ochratoxins; C025589:ochratoxin A; D016604:Aflatoxin B1