Upconversion fluorescence immunoassay for imidaclothiz by magnetic nanoparticle separation

Abstract

A sensitive fluorescence immunoassay for the detection of imidaclothiz was established by using magnetic nanoparticles (MNPs) as concentration elements and upconversion nanoparticles (UCNPs) as signal labels. The NaYF/Yb,Er UCNPs and MNPs were conjugated with imidaclothiz monoclonal antibody and imidaclothiz antigen, respectively. Imidaclothiz could compete with the antigen-conjugated MNPs for binding to the antibody-conjugated UCNPs and resulted in a decreased fluorescence signal when the MNPs were separated by an external magnet. Under the optimal conditions, the concentration of imidaclothiz producing 50% inhibition of the signal (IC), limit of detection (LOD, IC), and the linear assay range (IC-IC) were 14.59, 0.74, and 0.74-289.30 ng mL, respectively. The immunoassay exhibited no obvious cross-reactivity with analogues of imidaclothiz except for imidacloprid, with 89.2% cross-reactivity. The average recoveries measured in paddy water, pear, soil, peach, rice, tomato, wheat, and pakchoi were 75.7-105.2%, and the relative standard deviations (RSDs) were less than 11.2%. In addition, the results of the immunoassay correlated well with that of high-performance liquid chromatography (HPLC) for authentic samples. Graphical abstract Development of an upconversion fluorescence immunoassay for the detection of imidaclothiz by using antibody-modified upconversion nanoparticles (UCNPs) as the detection probe and antigen-modified magnetic nanoparticles (MNPs) as the capture probe.

Optical-Based (Bio) Sensing Systems Using Magnetic Nanoparticles

“…Furthermore, MNPs can be adopted to utilize as contrast agents for magnetic resonance imaging (MRI) [100,109,110]. Magneto-fluorometric methods for sensing of numerous materials such as heavy metals [111,112], toxins [113], drugs [114,115], pesticide [116], biological materials i.e. DNA [117,118], cell [119,120], bacteria [121], etc.…”

Competitive and noncompetitive immunoassays for the detection of benzothiostrobin using magnetic nanoparticles and fluorescein isothiocyanate-labeled peptides

“…Black polystyrene 96well microtiter plates with a nonbinding surface treatment were purchased from Corning Costar Corporation (NY, USA). Anti-benzothiostrobin mAb 4E 8 [27] and MNPs [28] were prepared previously and stored in the laboratory. The phage-displayed peptides (C3-3, CSGLAEFMSC and N6-18, CPDIWPTAWC) were isolated from a cyclic 8-amino-acid random peptide library previously [11].…”

“…The mAb was conjugated to the MNPs according to the method previously described [28]. Briefly, 10 mg of MNPs were thoroughly dispersed in 5 mL of 0.05 M, pH 7.4 sodium borate buffer (BB) by ultrasonication for 1 h. Subsequently, 100 mg sodium borohydride (NaBH 4 ) and 1.25 mL of glutar-aldehyde (25%) were added and the mixture was shaken for 1 h. The MNPs were separated by a magnetic separator and washed three times with BB.…”

Evaluation of an Element-Tagged Duplex Immunoassay Coupled with Inductively Coupled Plasma Mass Spectrometry Detection: A Further Study for the Application of the New Assay in Clinical Laboratory

“…However, the problems of waste disposal, limited stability and radioisotopes pollution restricted the use of the RIA method [6]. Regarding the problem, a variety of sophisticated non-radioactive immunoassays had gradually been proposed, including enzyme linked immunosorbent assay (ELISA), fluorescence immunoassay (FIA), time resolved fluorescence immunoassay (TAFIA), chemiluminescent immunoassay (CLIA), and electrochemiluminescent immunoassay (ECLIA) [4,[7][8][9][10][11][12]. However, these conventional immunoassay methods are often significantly limited for simultaneous multianalyte quantification.…”