An Ultrasensitive Electrochemical Immunosensor for Nonylphenol Leachate from Instant Noodle Containers in Southeast Asia

Abstract

Nonylphenols (NPNs) are persistent endocrine disruptors and their release into the environment is causing increasing concern about their impact on human health. Herein, an ultrasensitive electrochemical immunosensor was developed for the detection of NPNs in the leachates from 61 instant noodle containers (INCs) from 8 countries across Southeast Asia. Gold nanoclusters (AuNCs) were self‐assembled with reduced graphene oxide (rGO; polyethylenimine–rGO) and used to modify a glassy carbon electrode (GCE), which showed excellent electrical conductivity. An anti‐NPN antibody was then immobilized on the AuNCs and, if it specifically bound NPN, the reduction in conductivity of the GCE was remarkable. The designed immunosensor has a low detection limit (5.25 ng L−1) and high sensitivity for NPNs in the leachates of INCs. Remarkably, the leaching of estrogen‐like compounds from different plastics of INCs and the correlation between NPN content and total estrogenic activity were thoroughly investigated. High temperatures caused polyethylene and polystyrene INCs to release more estrogen‐like compounds than that of polypropylene INCs; this increased release of NPNs was associated with higher estrogen activity in living cells. These data fill the gap in human and environmental exposure to estrogen‐like compounds through INCs.

An Electrochemical Sensor Based on Gold-Nanocluster-Modified Graphene Screen-Printed Electrodes for the Detection of β-Lactoglobulin in Milk

“…Then, the mixture was centrifuged (3000× g, 5 min), and the supernatant was discarded. The precipitate was washed three times and resuspended in DI water (0.5 mg/mL) [33].…”

“…For example, the experiments of Eissa et al [32] required multiple cyclic voltammetry scans to complete the modification of the sensor and the fixation of the antibody. In this study, we used self-assembly of rGO modified with polyethyleneimine (PEI) and AuNCs to obtain a composite material (PEI-rGO-AuNCs) for the surface modification of the working electrode of a set of screen-printed electrodes, which was successfully proved to detect the nonylphenols with a low detection limit [33]. The electrode surface can be modified by a simple drip coating method.…”

Recent advances in nanomaterial‐assisted electrochemical sensors for food safety analysis

“…The immunosensor displays a low LOD (1.2 × 10 −11 mol L −1 ), and acceptable recoveries (84.6%–100.3%) in real sample detection. So far, widespread reports have demonstrated that label‐free electrochemical immunosensors perform well in analyzing different food safety hazards such as chloramphenicol (El‐Moghazy et al., 2018), tetracycline (El Alami El Hassani et al., 2019), Escherichia coli (Y. Huang et al., 2019; Mathelié‐Guinlet et al., 2019), nonylphenols (M. Lu et al., 2019), parathion (Mehta et al., 2016), ochratoxin A (Kunene et al., 2020; Malvano et al., 2016), and aflatoxin M1 (An et al., 2020). Apart from being labeled on antibodies, nanozymes as electrode modifiers can be used for the design of flexible label‐free immunosensing strategies for food safety hazard analysis.…”

An Electrochemical Molecularly Imprinted Polymer Sensor for Rapid β-Lactoglobulin Detection

“…Excess GSH-modified Au-NCs were added to the PEI-rGO solution. After 3 min of sonication and 5 min of 3000× g centrifugation, the PEI-rGO-Au-NCs was obtained by discarding the supernatants [28][29][30].…”