A reagentless electrochemical immunosensor for sensitive detection of carcinoembryonic antigen based on the interface with redox probe-modified electron transfer wires and effectively immobilized antibody

Abstract

Convenient and sensitive detection of tumors marked in serum samples is of great significance for the early diagnosis of cancers. Facile fabrication of reagentless electrochemical immunosensor with efficient sensing interface and high sensitivity is still a challenge. Herein, an electrochemical immunosensor was easily fabricated based on the easy fabrication of immunoassay interface with electron transfer wires, confined redox probes, and conveniently immobilized antibodies, which can achieve sensitive and reagentless determination of the tumor marker, carcinoembryonic antigen (CEA). Carboxyl multi-walled carbon nanotubes (MWCNTs) were firstly modified with an electrochemical redox probe, methylene blue (MB), which has redox potentials distinguished from those of redox molecules commonly existing in biological samples (for example, ascorbic acid and uric acid). After the as-prepared MB-modified MWCNT (MWCNT-MB) was coated on the supporting glassy carbon electrode (GCE), the MWCNT-MB/GCE exhibited improved active area and electron transfer property. Polydopamine (PDA) was then in situ synthesized through simple self-polymerization of dopamine, which acts as the bio-linker to covalently immobilize the anti-CEA antibody (Ab). The developed immunosensor could be applied for electrochemical detection of CEA based on the decrease in the redox signal of MB after specific binding of CEA and immobilized Ab. The fabricated immunosensor can achieve sensitive determination of CEA ranging from 10 pg/ml to 100 ng/ml with a limit of detection (LOD) of 0.6 pg/ml. Determination of CEA in human serum samples was also realized with high accuracy.

Highly Sensitive Electrochemical Detection of Paraquat in Environmental Water Samples Using a Vertically Ordered Mesoporous Silica Film and a Nanocarbon Composite

“…Porous materials have been used as important functional building blocks for the development of various high-performance sensors and nanofluidic osmotic power generators [ 14 , 15 , 16 ], taking advantage of the high porosity and surface area [ 17 , 18 ], efficient enrichment ability [ 19 , 20 ] and rapid mass transfer [ 21 ], as well as their ease of hybridization [ 22 , 23 , 24 ]. In particular, vertically ordered mesoporous silica films (VMSF) consisting of ultrasmall and uniform pores (2~3 nm), perpendicular silica nanochannels and high porosity exhibit unique characteristics in terms of their good molecular accessibility, high permselectivity (e.g., size [ 25 ], charge [ 26 ] and lipophilicity [ 27 ]) and excellent anti-fouling capacity [ 28 ].…”

Simple immunosensor for ultrasensitive electrochemical determination of biomarker of the bone metabolism in human serum

“…Chitosan (CS), the product from natural polysaccharide chitin obtained through the removal of part of the acetyl group, has the characteristics of easy degradation and good biocompatibility. Numerous amino groups in CS can be used to immobilize functional substances such as proteins or nanoparticles (Qiu et al, 2009;Zhang J. et al, 2022). However, direct modification of electrodes using CS suffers from high interfacial resistance as CS is a nonconductive material.…”

A simple electrochemical immunosensor based on a chitosan/reduced graphene oxide nanocomposite for sensitive detection of biomarkers of malignant melanoma

“…The introduction of functional nanomaterials to improve the performance of electro-chemical immunosensors has attracted much attention in recent years. 15,16 Graphene based materials have recently attracted great interests due to the unique structure, multidimensional scale (e.g. zero dimension-0D graphene quantum dots, [17][18][19] two dimensional-2D graphene nanosheets, [20][21][22] three-dimensional-3D graphene foam [23][24][25] ) and rich properties, such as good electrical conductivity, high surface area, and good hybridization ability with other functional materials etc.…”