Human apolipoprotein E4 (APOE4) is a major risk factor for Alzheimer's disease (AD) and can greatly increase the morbidity. In this work, an ultrasensitive sandwich-type electrochemical immunosensor for the quantitative detection of APOE4 was designed based on fractal gold (FracAu) nanostructures and enzyme amplification. The FracAu nanostructures were directly electrodeposited by hydrogen tetrachloroaurate (HAuCl4) on polyelectrolytes modified indium tin oxide (ITO) electrode. The sensing performances of the modified interface were investigated by cyclic voltammetry (CV). After functionalization with HRP-labeled APOE4 antibody, the human APOE4 could be detected quantitatively by current response. The current response has a linear relationship with the logarithm of human APOE4 concentrations in a range from 1.0 to 10,000.0 ng/mL, with a detection limit of 0.3 ng/mL. The fabricated APOE4 electrochemical immunosensor exhibits strong specificity, high sensitivity, low detection limit and wide linear range. The detection of human APOE4 provides a strong support for the prevention of AD and early-stage warning for those susceptible populations.
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http://dx.doi.org/10.1016/j.bios.2015.04.068 | DOI Listing |
Anal Chim Acta
February 2025
School of Chemistry and Chemical Engineering, University of Jinan, Jinan, 250022, PR China; Department of Chemistry, Sungkyunkwan University, Suwon, 16419, Republic of Korea. Electronic address:
Background: Estriol (E3) is a common estrogen responsible for regulating the female reproductive system, but excessive amount can pose health risks to humans and wild life. Therefore, sensitive and accurate detection of estriol level is crucial. A novel competitive ECL immunosensor based on a dual signal amplification strategy of AuNPs@GO@SmMoSe and Gd(MoO) was fabricated for ultrasensitive detection of estriol.
View Article and Find Full Text PDFMikrochim Acta
January 2025
College of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, 26 Yuxiang Road, Shijiazhuang, 050018, P. R. China.
An aptamer-antibody sandwich electrochemical immunosensor was studied. FeO/MWCNTs-COOH/Nafion was modified and fixed on a glassy carbon electrode to amplify electrical signals. The antibody was coupled with AuNPs to form conjugates.
View Article and Find Full Text PDFBiosensors (Basel)
January 2025
School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Hangzhou 310018, China.
The sensitive detection of inflammatory biomarkers in gingival crevicular fluid (GCF) is highly desirable for the evaluation of periodontal disease. Luminol-based electrochemiluminescence (ECL) immunosensors offer a promising approach for the fast and convenient detection of biomarkers. However, luminol's low ECL efficiency under neutral conditions remains a challenge.
View Article and Find Full Text PDFBiosensors (Basel)
January 2025
State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210092, China.
Herein, a sensitive electrochemiluminescence (ECL) immunosensor is designed by immobilizing ruthenium-tagged immune complexes at flexible poly-ethylene-glycol (PEG) chains on the electrode surface, which offers more freedom for the collision of the ruthenium complex at the electrode during the initial ECL reaction. The electrochemical characterizations confirm the loose structure of the assembled layer with the immune complex, providing an increase in the current and the resultant enhanced ECL emissions. Comparing the sensors with the rigid structure, a 34-fold increase in the maximal ECL emission is recorded when PEG3400 is used as a linker.
View Article and Find Full Text PDFAnal Methods
January 2025
Defence Research and Development Establishment, Jhansi Road, Gwalior, Madhya Pradesh 474002, India.
A sandwich electrochemical immunosensor was proposed for the sensitive detection of protective antigen ( PA) toxin based on cadmium sulphide nanocrystals (CdS NCs) and polypyrrole-gold nanoparticle-modified multiwalled carbon nanotubes (PPy-AuNPs/MWCNTs). Herein, PPy-AuNPs/MWCNTs were used as a biocompatible and conducting matrix for immobilization of rabbit anti-PA antibody [RαPA antibody, capturing antibody (Ab1)] and to facilitate excellent electrical conductivity. PPy-AuNPs/MWCNTs were synthesized through a one-step chemical reaction of pyrrole and Au on the surface of MWCNTs.
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