Ratiometric Immunosensor for GP73 Detection Based on the Ratios of Electrochemiluminescence and Electrochemical Signal Using DNA Tetrahedral Nanostructure as the Carrier of Stable Reference Signal

Abstract

DNA tetrahedron nanostructure (DTNs) has the merits of simple synthesis, high yield, structural stability, and mechanical rigidity, and its three-dimensional structure provides a satisfactory biosensing interface to the improvement of the binding efficiency of antigenic proteins and antibodies. Electrochemiluminescence (ECL) reagent, tris-(4,4′-dicarboxylicacid-2,2′-bipyridyl)ruthenium(II) dichloride (Ru(dcbpy) 3 Cl 2 ), was modified on the electrode through the formation of classical sandwich complex of antibody− antigen−antibody. ECL response of the system increased with the increment of the target (golgi protein 73 (GP73) in this study) with high selectivity. Besides, the composed double-stranded DNA (dsDNA) in each side of DTNs could act as an excellent carrier of methylene blue (MB), thus producing a stable electrochemical internal reference signal on the electrode surface to correct the potential interferences. Therefore, a highly selective and reproductive ratiometric immunosensor was developed on the basis of the ratio of ECL of Ru(dcbpy) 3 Cl 2 and electrochemistry of MB. The ratio value of the ECL/ electrochemistry had a linear relationship with GP73 concentration in the range of 15 pg/mL−0.7 ng/mL, and the limit of detection was 15 pg/mL. The proposed ratiometric ECL immunoassay has been applied to detect GP73 in real serum samples with satisfactory results.

The TDs/aptamer cTnI biosensors based on HCR and Au/Ti3C2-MXene amplification for screening serious patient in COVID-19 pandemic

“…As shown in Fig. 1 B, the approximate diameter (6.50 ±0.8 nm) of TDs with uniform nanostructure estimated by TEM characterization was close to the calculated value (6.12 nm)( Lin et al, 2019 ; Zhu et al, 2019a ). The AFM image exhibited TDs nanostructure ( Fig.…”

“…Transmission electron microscopy (TEM), and atomic force microscopy (AFM) were performed to further character the morphology and size of TDs ( Lin et al, 2019 ). As shown in Fig.…”

“…Also it provides the solution-phase-like environment to improve the probe-target recognition efficiency by effective elimination of nonspecific adsorption of non-targets ( Chen et al, 2019 ; Chen et al, 2014 ; Huang et al, 2018 ; Pei et al, 2013 ; Pei et al, 2014 ). Thus it greatly promotes the application of biosensors ( Lin et al, 2019 ; Sun et al, 2019 ; Zhu et al, 2019a ).…”

“…The ratiometry is relied on the ratio of two different signals rather than a single signal for quantitative analysis ( Wu et al, 2017 ), which would improve the accuracy and reduce false results. A novel ratiometric strategy of ECL to EC was recently developed ( Lin et al, 2019 ; Zhu et al, 2019a ).…”

Nanobioconjugates for Signal Amplification in Electrochemical Biosensing

“…The immunosensor response was linear, ranging from 15 pg/mL to 0.7 ng/mL, with a LOD of 15 pg/mL. The device was able to detect the antigen present in real samples [ 144 ].…”