▎ 摘　　要

NOVELTY - Detecting glypican-3 (GPC3) comprises weighing and placing graphene oxide in ultrapure water, adding copper (II) nitrate and sodium hydroxide, and then adding hydrazine hydrate in a nitrogen-filled environment to obtain reduced graphene oxide-cuprous oxide nanocomposite (RGO-Cu2O NCs) solution. The screen-printing electrode (SPE) is placed in sulfuric acid, activated by cyclic voltammetry, immersed the activated SPE in chloroauric acid solution under constant potential deposition, and rinsed with ultrapure water to obtain gold nanoparticles/ screen printing electrode (AuNPs/SPE). USE - Method for detecting glypican-3 (GPC3) used as an electrochemical signal probe. ADVANTAGE - The obtained RGO-Cu2O nano-material has high specific surface area, high electron transfer efficiency, excellent peroxidase property, high load capacity, and can catalyze decomposition of hydrogen peroxide. DETAILED DESCRIPTION - Detecting glypican-3 (GPC3) comprises weighing and placing graphene oxide in ultrapure water, adding copper (II) nitrate and sodium hydroxide, and then adding hydrazine hydrate in a nitrogen-filled environment to obtain reduced graphene oxide-cuprous oxide nanocomposite (RGO-Cu2O NCs) solution. The screen-printing electrode (SPE) is placed in sulfuric acid, activated by cyclic voltammetry, immersed the activated SPE in chloroauric acid solution under constant potential deposition, and rinsed with ultrapure water to obtain gold nanoparticles/ screen printing electrode (AuNPs/SPE). The obtained RGO-Cu2O NCs solution is added dropwise on Au/SPE, incubated at a constant temperature, and then washed with phosphate-buffered saline (PBS) to obtain RGO-Cu2O NCs/AuNPs/SPE. The glypican-3 (GPC3) solution is added on RGO-Cu2O NCs/AuNPs/SPE, and then incubated and washed with PBS to obtain GPC3apt/RGO-Cu2O NCs/Au NPs/SPE. A bovine serum albumin (BSA) solution is added to the surface of GPC3apt/RGO-Cu2O NCs/Au NPs/SPE, incubated to block non-specific binding sites, washed and dried to obtain an electrochemical sensing interface for use. The standard GPC3 solution is added dropwise on the obtained electrochemical sensing interface, and incubated at constant temperature to obtain GPC3/GPC3apt/RGO-Cu2O NCs/Au NPs/SPE electrode. The prepared electrode is put into PBS buffer, scanned with differential pulse voltammetry (DPV), and recorded the change of the response current value of the sensor. After adding the hydrogen peroxide solution to the PBS buffer using the amperometry (i-t) method to scan, and recorded the change of the response current value of the sensor. The different concentrations of GPC3 is detected respectively, recorded the peak current, drawn two working curves according to the relationship between the peak current and GPC3 concentration, and then calculated the minimum detection limit of the method. The different kinds of human serum samples and GPC3 standard solution are mixed at a ratio of 1:1 to make the actual sample solution to be tested, dropped the actual sample solution to be tested on the prepared sensing interface, and then incubated and washed to get the working electrode. The working electrode is put into the PBS buffer, scanned with DPV, and recorded the response current value of the sensor. The concentration of GPC3 according to the obtained working curve in the actual serum sample is calculated. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the electrochemical aptamer sensor based on RGO-Cu2O nanomaterials for dual-signal detection of GPC3.