Lateral Flow Immunoassay Based on Polydopamine-Coated Gold Nanoparticles for the Sensitive Detection of Zearalenone in Maize

Abstract

In this work, polydopamine-coated gold nanoparticles (Au@PDAs) were synthesized by the oxidative self-polymerization of dopamine (DA) on the surface of AuNPs and applied for the first time as a signal-amplification label in lateral flow immunoassays (LFIAs) for the sensitive detection of zearalenone (ZEN) in maize. The PDA layer functioned as a linker between AuNPs and anti-ZEN monoclonal antibody (mAb) to form a probe (Au@PDA-mAb). Compared with AuNPs, Au@PDA had excellent color intensity, colloidal stability, and mAb coupling efficiency. The limit of detection of the Au@PDA-based LFIA (Au@PDA-LFIA) was 7.4 pg/mL, which was 10-fold lower than that of the traditional AuNP-based LFIA (AuNP-LFIA) (76.1 pg/mL). The recoveries of Au@PDA-LFIA were 93.80–111.82%, with the coefficient of variation of 1.08–9.04%. In addition, the reliability of Au@PDA-LFIA was further confirmed by the high-performance liquid chromatography method. Overall, our study showed that PDA coating can chemically modify the surface of AuNPs through a simple method and can thus significantly improve the detection sensitivity of LFIA.

On-Site Detection of Carcinoembryonic Antigen in Human Serum

“…The average ζ-potential for GNPs is −15.6 ± 1.4 mV, which is reduced by the formation of the PDA layer around them, reaching as low as −29.2 ± 2.3 mV. This is mainly attributed to the abundance of hydroxyl groups in the PDA layer [20]. After the immobilization of Abs on the nanoparticles' surface, due to the positive charge of Abs at pH 7.5, the ζ-potential is increased slightly (−28.0 ± 1.6 mV).…”

“…The GNP@PDA was then synthesized as stated by an earlier work [20], with some modifications. In brief, the pH of the prepared GNPs (1 mL) was set to 7.5 by adding 0.1 mol/L K 2 CO 3 solution, followed by the addition of 5 µL of 3% H 2 O 2 .…”

“…The mouse monoclonal antibody against human CEA (mAb) was conjugated to the GNPs (OD = 1) or corresponding GNP@PDA via simple mixing [20]. To this end, different values of mAb were added dropwise to 1 mL of GNPs or GNP@PDA solution, and after gentle shaking at 4 • C overnight, the mixture was blocked with 2% BSA for 1 h. Subsequently, via centrifugation at 9000 rpm for 20 min, the conjugates were re-suspended in 50 µL of 0.005 mol/L borate buffer containing 5% sucrose and 1% BSA.…”

“…The other approach is the utilization of functional polymers for the encapsulation of GNPs, which not only stabilize nanoparticles, but also provide an active layer for subsequent immobilization of Abs. In this regard, Xu et al [20] modified the surface of GNPs with a polydopamine layer (GNP@PDA) and used it in a competitive-type LFIA for the sensitive detection of zearalenone in maize, where there was an indirect relation between the visual signal and the target concentration. To the best of our knowledge, the efficiency and behavior of the GNP@PDA tag has not been investigated in a sandwich-type LFIA, and its advantageous quantification via smartphone-based module has not yet been reported.…”

Biosensor Technologies for Early Detection and Quantification of Plant Pathogens

“…Lateral flow immunoassays, based on colloidal gold nanoparticles, have been developed for several plant pathogens including for Potato Virus X in potato ( Drygin et al, 2012 ), Fusarium species in maize ( Xu et al, 2019 ) and Pantoea stewartii subsp. stewartii (Pss) bacteria in maize ( Zhang et al, 2014 ; Feng et al, 2015 ).…”