A colorimetric method for determination of the prostate specific antigen based on enzyme-free cascaded signal amplification via peptide-copper(II) nanoparticles
Biotinylated peptide-Cu2+ nanoparticles (Cu-P NPs) were synthesized via “one-pot” self-assembly. The peptide P conststs of a hydrophobic dipeptide (FF), a tripeptide (KGH), and a biotin moiety attached to the terminal amino group of the Lys residue. The Cu-P NPs contain abundant catalytically active Cu2+ ions which are liberated by acid-induced dissolution. The released Cu2+ ions catalyze the oxidization of 3,3′,5,5′-tetramethylbenzidine (TMB) by H2O2 because of their intrinsic peroxidase activity, and this results in the formation of a blue-green coloration. Based on the streptavidin–biotin interaction, the Cu-P NPs were employed to establish an enzyme-free colorimetric method for determination of prostate-specific antigen (PSA) as a model biomarker. Under optimal conditions, the linear response range is 0.001–1 ng mL−1, with a limit of detection as low as 1 pg mL−1.
KeywordsColorimetric immunoassay Enzyme-free amplification Cu2+ ion Peptide self-assembly Prostate specific antigen
We acknowledge the financial support of the Henan Province University Innovation Talents Support Program (18HASTIT005), the Science & Technology Foundation of Anyang City, and the First Class Discipline-Chemistry of Guizhou Education University (2019YLXKB03).
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