A White Light Reflectance Spectroscopy Label-Free Biosensor for the Determination of Fungicide Carbendazim

Georgios Koukouvinos,Evangelia Livaniou,Chrysoula-Evangelia Karachaliou,Sotirios Kakabakos

doi:10.3390/iecb2020-07021

Georgios Koukouvinos, Evangelia Livaniou + Show 2 more

Open Access

https://doi.org/10.3390/iecb2020-07021

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Publication Date: Nov 2, 2020
Citations: 1	License type: CC BY 4.0

Affiliation: National Centre of Scientific Research "Demokritos"

Abstract

Carbendazim is a broad-spectrum benzimidazole-type fungicide effective against fungi that compromise the safety/quality of food products. Despite its potential usefulness, carbendazim constitutes a major environmental pollutant, being hazardous for humans and animals; therefore, reliable determination of carbendazim levels in water, soil, and food samples remains a highly desirable analytical goal. Herein, an optical (white light reflectance spectroscopy, WLRS) label-free biosensor for fast and sensitive determination of carbendazim is presented. The transducer is a SiO2/Si chip, on which a suitable benzimidazole-conjugate has been immobilized; determination is based on the competitive immunoassay format: A mixture of an in-house developed anti-carbendazim antibody with the calibrators/samples is pumped over the chip, followed by biotinylated secondary antibody and unlabeled streptavidin. The WLRS platform allows for real-time monitoring of biomolecular interactions carried out onto the SiO2/Si chip by transforming the shift in the reflected interference spectrum caused by the immunoreaction to effective biomolecular adlayer thickness. The sensor is capable of detecting carbendazim levels within 28 min (LoD: 20 ng/mL; intra- and inter-assay CVs: ≤6.9% and ≤9.4%, respectively). Excellent analytical characteristics and short analysis time combined with its small size render the proposed WLRS biosensor ideal for future point-of-need determination of carbendazim in food and environmental samples.

Highlights

Fungal pathogens cause significant damages to the food crops every year resulting in poor yield, deficient food quality and huge economic loss; the use of fungicides gains ground to circumvent these problems [1]
Carbendazim determination is based on the competitive immunoassay format, i.e., a mixture of the antibody with the calibrators or the samples is pumped over the chip surface followed by reaction with biotinylated secondary antibody/streptavidin for signal enhancement
Due to the competitive nature of the assay, the two most crucial parameters to optimize were the concentration of benzimidazole-conjugate used for coating and the concentration of anti-carbendazim antibody, since their combination determines the highest signal and the assay sensitivity

Summary

Introduction

Fungal pathogens cause significant damages to the food crops every year resulting in poor yield, deficient food quality and huge economic loss; the use of fungicides gains ground to circumvent these problems [1]. Proceedings 2020, 4, x FOR PEER REVIEW this context, carbendazim has been documented to induce infertility, embryotoxicity, teratogenicity, hepatocellular dysfunction, endocrine-disrupting effects, disruption of haematological functions and mutagenicity [2]. Due to its afore-mentioned severe toxicities and its persistence in food and the environment, carbendazim has been officially banned in most of European Union, USA and Australia. Some countries, such as UK, Portugal, India, China and Brazil are still permitting the production and use of carbendazim in various formulations [5], raising a growing concern for the health and safety of humans and animals

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