Superwettable Dendritic Gold Nanostructured Electrode Arrays for Electrochemical Enzyme-Linked Immunosorbant Assay (ELISA)

摘要

Hydrophobic/hydrophilic patterning on dendritic gold nanostructures (Au-DNs) provides an attractive platform for biosensing. However, the rapid fabrication of superwettable Au-DNs without hydrophobic molecular modifications remains highly challenging. Here, we used a simple heating method to convert Au-DNs electrodeposited on indium tin oxide (ITO)-coated glass from superhydrophilic to superhydrophobic. Nine gapped rings (each with a diameter of 2 mm, width of 160 mu m, and gap of 0.5 mm) were etched on the superhydrophobic Au-DNs/ITO electrode (2 cm x 3 cm) with a laser engraver. The laser-etched rings are hydrophilic and combine with the enclosing superhydrophobic regions to form superwettable microwells that serve as an array of working electrodes. The superwettable Au-DNs/ITO electrode arrays were used as the working electrode for electrochemical enzyme-linked immunosorbant assay (ELISA) detection of human immunoglobulin (IgG). In the electrochemical ELISA, the capture antibody (goat anti-human IgG) was immobilized onto the Au-DNs/ ITO electrode, and the labeled antibody was labeled with horseradish peroxidase. After the immunoreaction, 10 mu L of droplets containing hydrogen peroxide were added to the superwettable microwells. Differential pulse voltammetry was used to measure the peak currents of the droplets at approximately -0.07 V. The calibration curve of peak current intensity versus IgG concentration is linear in the range of 5-250 ng/mL, with a detection limit of 3.61 ng/mL. The electrochemical immunosensor exhibits high selectivity, reproducibility and recovery, and was applied to detect IgG in real serum samples, demonstrating its promising application in clinical diagnosis.

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