A sensitive immunoassay for simultaneous detection of foodborne pathogens using MnO2 nanoflowers-assisted loading and release of quantum dots. (30th August 2020)

• Record Type: Journal Article
• Authors: Xue, Li; Huang, Fengchun; Hao, Li; Cai, Gaozhe; Zheng, Lingyan; Li, Yanbin; Lin, Jianhan
• Is Part Of: Food chemistry. Volume 322(2020)
• Publication Date: 2020-08-30
• Subjects: Fluorescent immunoassay -- Manganese dioxide nanoflowers -- Quantum dots -- Simultaneous detection -- Pathogenic bacteria; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2020.126719
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: It's the first time to combine MnO2 NFs with QDs to amplify biological signals. Releasing QDs from fluorescent bacteria effectively enhanced fluorescent signals. The detection limit for E. coli and Salmonella was as low as 10 1 CFU/mL. The mean recovery was ∼96% for E. coli and Salmonella in spiked samples. Abstract: In this study, a sensitive immunoassay using immunomagnetic nanobeads (MNBs), manganese dioxide nanoflowers (MnO2 NFs) and quantum dots (QDs) was developed for simultaneous detection of E. coli O157: H7 and Salmonella typhimurium. MnO2 NFs were synthesized, functionalized and incubated with QDs to obtain QDs@MnO2 nanocomposites, followed by modification with antibodies (pAbs) to obtain pAb-QDs@MnO2 nanocomposites (QM NCs). Target bacteria were first conjugated with MNBs and QM NCs to form MNB-bacteria-QM complexes. Then, QDs were quickly released from the complexes using glutathione to reduce MnO2 to Mn 2+ . Finally, fluorescent intensity at characteristic wavelength was measured by optical detector to determine target bacteria. This immunoassay could simultaneously and quantitatively detect E. coli from 1.5 × 10 1 to 1.5 × 10 6 CFU/mL with detection limit of 15 CFU/mL and Salmonella from 4.0 × 10 1 to 4.0 × 10 6 CFU/mL with detection limit of 40 CFU/mL in 2 h. The mean recovery for both bacteria in spiked chicken samples was ∼96%.