An Innovative Nanobody-Based Electrochemical Immunosensor Using Decorated Nylon Nanofibers for Point-of-Care Monitoring of Human Exposure to Pyrethroid Insecticides

Abstract

A novel ultrasensitive nanobody-based electrochemical immunoassay was prepared for assessing human exposure to pyrethroid insecticides. 3-Phenoxybenzoic acid (3-PBA) is a common human urinary metabolite for numerous pyrethroids, which broadly served as a biomarker for following the human exposure to this pesticide group. The 3-PBA detection was via a direct competition for binding to alkaline phosphatase-embedded nanobodies between free 3-PBA and a 3-PBA-bovine serum albumin conjugate covalently immobilized onto citric acid-decorated nylon nanofibers, which were incorporated on a screen-printed electrode (SPE). Electrochemical impedance spectroscopy (EIS) was utilized to support the advantage of the employment of nanofibrous membranes and the success of the immunosensor assembly. The coupling between the nanofiber and nanobody technologies provided an ultrasensitive and selective immunosensor for 3-PBA detection in the range of 0.8 to 1000 pg mL–1 with a detection limit of 0.64 pg mL–1. Moreover, when the test for 3-PBA was applied to real samples, the established immunosensor proved to be a viable alternative to the conventional methods for 3-PBA detection in human urine even without sample cleanup. It showed excellent properties and stability over time.

Alkaline Phosphatase‐based Electrochemical Analysis for Point‐of‐Care Testing

“…The electrochemical signals of 1-NP can be selectively detected in the presence of 1-NPP because their oxidation potentials do not overlap, similar to the PAPP/PAP couple [25]. Recent studies have used Au [26] and carbon-based [27][28][29] electrodes to detect 1-NP. Cyclic voltammetry of 1-NP shows only one oxidation peak because of its irreversible conversion to an electropolymerized derivative [18,30].…”

“…Nbs have several advantages, such as ease of cloning and expression, thermal and chemical stability, and high solubility, compared to traditional antibodies [48,49]. In 2020, A. Y. El-Moghazy et al applied ALP-linked Nbs to an electrochemical POCT device [29]. They assessed human exposure to pyrethroid pesticides by detecting 3-phenoxybenzonic acid (3-PBA), which is a metabolite from the hydrolysis of numerous pyrethroid pesticides.…”

Photothermal-Induced Electrochemical Interfacial Region Regulation Enables Signal Amplification for Dual-Mode Detection of Ovarian Cancer Biomarkers

“…To date, an immunoassay has been a predominant analytical method in the early diagnosis of tumor markers, which relies on the strict recognition between antigens and antibodies to ensure detection specificity. , Recently, various immunoassays have been developed for the detection of tumor markers, including fluorescence, chemiluminescence, electrochemiluminescence, photoelectrochemical, etc. Among them, electrochemical immunosensors have attracted substantial attention benefiting from their high sensitivity, fast response, simple setup, and easy miniaturization. , To further improve the analytical performance of an immunosensor, it is of paramount importance for developing an effective signal amplification strategy to meet the demand of high sensitivity in clinical diagnosis.…”

Detection of Cardiovascular CRP Protein Biomarker Using a Novel Nanofibrous Substrate

“…Some of the previous efforts in developing biosensors based on nanofibers involved citric acid-decorated nylon nanofibers for the detection of 3-phenoxybenzoic acid (3-PBA), a common human urinary metabolite [14], and polyvinyl alcohol-co-ethylene (PVA-co-PE)-based nanofibrous membranes for the detection of chloramphenicol (CAP) residues in milk [15]. One of the aspects of polyvinyl alcohol (PVA) and carbon nanotube (CNT)-based nanofibrous biological recognition elements is that they offer spatial confinement similar to the intracellular environment through porosity.…”