An Electrochemical Sandwich Immunosensor Based on Signal Amplification Technique for the Determination of Alpha-Fetoprotein

Abstract

The synthesis of Au nanocubes is used to label alpha-fetoprotein antibody (anti-AFP) and horseradish peroxidase (HRP) to form an immune complex for antibody detection. Graphene oxide-methylene blue-gold nanoparticles (GO-MB-AuNPs) nanocomposites were used as the immunosensing platform. This proposed sandwich-type immunoassay shows good performance. This method establishes a feasible amperometric immunoassay method for sensitive analysis of AFP in serum samples. Under the optimal experimental conditions, the DPV current response of the immunosensor is proportional to the logarithmic value of the AFP concentration. The linear detection range can achieve to 0.005-20 ng/mL with a detection limit of 1.5 pg/mL. The proposed immunosensor has good precision, selectivity and stability, and can be used for AFP determination in clinical tests.

Dual-Mode and Label-Free Detection of Exosomes from Plasma Using an Electrochemical Quartz Crystal Microbalance with Dissipation Monitoring

“…Similar impedance increases upon immunosensor fabrication have been reported in literature. 59 − 61 It is interesting to note the extent to which R ct increased for each sensing layer ( Figure 2 C). Here, the net changes in resistance is the increase in R ct upon analyte addition from the previous (pre-analyte) baseline.…”

A sandwich-like configuration with a signal amplification strategy using a methylene blue/aptamer complex on a heterojunction 2D MoSe2/2D WSe2 electrode: Toward a portable and sensitive electrochemical alpha-fetoprotein immunoassay

“…Ab 2 /AuNPs/GCE Pd/APTES-M-CeO 2 -GO-Ab 2 Amp 0.0001-50 3.3×10 -6 (Wei et al, 2016) Ab 1 /GO-MB-AuNPs/GCE AuC-HRP-Ab 2 DPV 0. 005-20 1.5×10 -3 (Shen et al, 2020) Ab 1 /AuNPs-GO/GCE P(VT-co-HEMA)-g-GO/Ab 2 SWV 0.025 -50 1.8×10 -2 (Zhao et al, 2020) Ab 1 /3D AuE HRP/Ab 2 Amp 0.005-50 3.0×10 -3 (Zhong et al, 2015) Ab 1 /rGO-TEPA-Thi-AuNPs/SPCE CMK-3@AuPtNPs-Ab 2 Amp 0.005-100 2.2×10…”

“…In addition, they can be operated with simplicity, high selectivity, high sensitivity, and good stability ( Pei et al., 2019 ; Zhao et al., 2019 ). During the detection of target analytes, the immunocomplex generally forms on the sensing surface via molecular recognition by primary antibody and then signal amplification is performed by the formation of a sandwich immunocomplex with another detection or secondary antibody tagged with enzymes ( Zhong et al., 2015 ; Shen et al., 2020 ), metals ( Wei et al., 2016 ; Liu et al., 2017 ; Wang et al., 2018 ), nanoparticle nanotags ( Wei et al., 2016 ; Putnin et al., 2019 ; Zhao et al., 2020 ; Xiao et al., 2021 ), and redox probes ( Gao et al., 2014 ; Rong et al., 2021 ). The preparation of labeled antibodies requires many steps and costly chemicals; moreover, tagging with biomolecules would cause instability in the detection because they are environmentally sensitive.…”

A Microfluidic Chip-Based MRS Immunosensor for Biomarker Detection via Enzyme-Mediated Nanoparticle Assembly

“…Under the above optimized conditions, we compare the analytical performance of the MRS sensor and conventional pNPP (para-nitrophenylphosphate)-based ELISA for the detection of AFP. AFP is a tumor marker for the diagnosis of primary liver cancer (Jalanko et al, 1978;Shen et al, 2020). A high AFP generally means the occurrence of liver cancer.…”