An electrochemical non-enzymatic immunosensor for ultrasensitive detection of microcystin-LR using carbon nanofibers as the matrix

Abstract

a b s t r a c tThis work designed an ultrasensitive non-enzymatic immunosensor for microcystin-LR (MC-LR) detection using carbon nanofibers (CNFs) as immobilization matrix and gold nanoparticles (AuNPs) as an electrochemical label. The carboxylic group functionalized CNFs could well disperse in water for at least three months, and CNFs modified electrode showed high conductivity and enhanced electron transfer. The immunosensor was constructed by immobilizing MC-LR antigen on CNFs modified electrode. With a competitive immunoassay format, the coated MC-LR antigen competed for MC-LR antibody with added target MC-LR to form antibody-antigen immunocomplex. Subsequently, the immunocomplex reacted with AuNPs labeled secondary antibodies, and the bound AuNPs were finally electro-oxidized in 0.1 M HCl to produce AuCl 4 − for differential pulse voltammetric detection of MC-LR. Under optimal conditions, the immunosensor exhibited a wide linear response to MC-LR ranging from 0.0025 to 5 g L −1 with a detection limit of 1.68 ng L −1 at a signal to noise of 3. This method showed good accuracy, acceptable precision and reproducibility. The assay results of MC-LR in polluted water were in a good agreement with the reference values. The proposed ultrasensitive immunoassay showed the promising application in environmental monitoring and public health.

Direct Electrochemical Nano‐immunosensor for Microcystin‐LR in Seawater

“…Liquid crystal molecules have been used efficiently as redox probes in the development of label‐free immunosensors by our group in previous studies . The response of the proposed immunosensor at different Br‐Py concentrations (0.5, 1.0, 3.0 and 5.0 mmol L −1 ) was tested (Figure ‐B).…”

“…It was based on the affinity between this cyanotoxin and the corresponding monoclonal and polyclonal antibodies. Since then, several electrochemical immunosensorshave been developed for the detection of this substance .…”

“…The progress achieved in the field of nanotechnology has strongly influenced the development of immunosensors with improved analytical performance. Various nanomaterials have been explored in the construction of microcystin immunosensors, including metal nanoparticles , graphene , carbon nanotubes , metal nanorods and carbon nanofibers . These nanostructures improve the electron transfer efficiency and increase the surface area available for the immobilization of biomolecules.…”

Ultrasensitive electrochemical microcystin-LR immunosensor using gold nanoparticle functional polypyrrole microsphere catalyzed silver deposition for signal amplification

“…With the development of nanoscience and nanotechnology, quantum dot (QD) [16,17] and metallic nanoparticle [18][19][20] have been used as signal tags for signal enhancement and develop ultrasensitive enzyme-free MC-LR immunoassay. The QD-based detection requires harsh detection conditions, including nanocrystals dissolution, high potential accumulation, and deoxygenation, which is not suitable for application.…”

Electrochemical immunosensor based on carboxylated single‐walled carbon nanotube‐chitosan functional layer for the detection of cephalexin

“…Electrochemical immunosensor combines specific ELISA with highly sensitive sensing technology, good selectivity, and fast analyzing ability (Gayathri, Mayuri, Sankaran, & Kumar, 2016;Jing et al, 2016;Zhang, Li, Ma, Zhang, & Zheng, 2016). In recent years, the rapid development of nanomaterials technologies have drawn much research attention.…”