Electrochemical α-fetoprotein immunosensor based on Fe3O4NPs@covalent organic framework decorated gold nanoparticles and magnetic nanoparticles including SiO2@TiO2

Abstract

The early diagnosis of major diseases such as cancer is typically a major issue for humanity. Human α-fetoprotein (AFP) as a sialylated glycoprotein is of approximately 68 kD molecular weight and is considered to be a key biomarker, and an increase in its level indicates the presence of liver, testicular, or gastric cancer. In this study, an electrochemical AFP immunosensor based on Fe 3 O 4 NPs@covalent organic framework decorated gold nanoparticles (Fe 3 O 4 NPs@COF/AuNPs) for the electrode platform and double-coated magnetic nanoparticles (MNPs) based on SiO 2 @TiO 2 (MNPs@SiO 2 @TiO 2 ) nanocomposites for the signal amplification was fabricated. The immobilization of anti-AFP capture antibody was successfully performed on Fe 3 O 4 NPs@COF/AuNPs modified electrode surface by amino-gold affinity, while the conjugation of anti-AFP secondary antibody on MNPs@SiO 2 @TiO 2 was achieved by the electrostatic/ionic interactions. Transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) analysis, cyclic voltammetry (CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy (EIS) techniques were used to characterize the nanostructures in terms of physical and electrochemical features. The limit of detection (LOD) was 3.30 fg mL −1 . The findings revealed that the proposed electrochemical AFP immunosensor can be effectively used to diagnose cancer.

Magnetic Molecularly Imprinted Nanoparticles for Rapid and Selective Detection of Dimethyl Phthalate in Water Using SERS

“…As part of its research effort, molecular imprinting technology uses molecular imprinting polymers (MIPs) to simulate enzyme–substrates or antibody–antigen interactions and to develop a method for specifically identifying imprinted molecules (also known as template molecules). As with synthetic “antibodies”, the molecular imprinting technology process involves binding template molecules with functional monomers, and the cross-linker creates a network of interaction through π–π interactions, hydrogen bonds, electrostatic interactions, and other types of interactions. − Generally speaking, it is a technology that allows the “artificial lock” to be customized in order to recognize a specific key (imprinted molecules) when it is used. In order to obtain specific identification, the template molecule is eluted from the polymer using an appropriate eluent in order to create an “imprinted site” that specifically identifies the template molecule.…”

Sensitive and Label‐Free Electrochemical Immunosensor for Alpha Fetoprotein Based on N‐Doped Hollow Nanocarbon Spheres Decorated with Gold Nanoparticles

“…[1][2][3] As a tumor biomarker, alpha fetoprotein (AFP) is the only primary serologic marker in the early diagnosis of liver cancer. [4][5][6][7][8] The AFP concentration is commonly low to 3.4 ng mL À 1 in normal adults, when it exceeds than 20.0 ng mL À 1 , [9][10][11] the liver cancer is suspected. Consequently, designing simple and effective diagnosis proposal of AFP is essential.…”

“…[25][26][27][28][29] Generally, one of the key aspects in constructing an effective immunosensor is to design suitable carrier to assemble antibodies that are used to specifically recognize target antigens. Up to now, various nanomaterials (e. g., AuNPs@ ZIF-8, [2] gold nanoparticles-dextran-reduced graphene oxide, [6] Cu 3 Pt, [7] and Fe 3 O 4 NPs@ covalent organic framework [11] ) have been developed as carriers to assemble AFP antibody for fabricating electrochemical immunosensors of AFP. For instance, Heiat and Negahdary [30] prepared spindle-shaped Au modified electrode to develop an electrochemical nanoaptasensor for AFP; Li et al [31] constructed an electrochemical aptasensor for AFP based on thionin/ reduced graphene oxide/Au and AFP-aptamer.…”

Au Nanoparticles on Two-Dimensional MoWS2 as Highly Sensitive Surface-Enhanced Raman Spectroscopy Substrates for Adenine Detection

“…The diagnosis of diseases in modern medicine is closely intertwined with the detection of disease biomarkers. − Adenine is one of the most important biological molecules found in both DNA and RNA, which is associated with diseases including gout, hyperuricemia, and kidney stones. − The quantitative detection of adenine is of significance for better understanding its roles in biological processes and further validating its function in clinical diagnosis. Currently, common approaches for detecting adenine include liquid chromatography, visible light absorption spectroscopy, and electrochemical sensing. − However, these methods usually suffer from poor sensitivity or complex operation processes because of the low concentration of adenine in biological fluids and interference from other substances. − As a powerful analytical tool, Raman spectroscopy (RS) offers the potential for fingerprinting biological molecules at an ultralow concentration.…”