▎ 摘　　要

NOVELTY - Preparing prostate-specific antigen (PSA) aptamer sensor based on screen printing electrodes involves modifying composite of gold nanoparticles (AuNPs) and graphene airgel on the surface of screen-printed electrodes, realizing modification on the surface of the screen-printed electrode by forming a gold-sulfur bond between the composite material and the sulfhydryl-modified PSA aptamer, and constructing PSA aptamer sensor. USE - Method for preparing PSA aptamer sensor based on screen printing electrodes is used as tumor marker of prostate cancer in the micro-nano biological detection field. ADVANTAGE - The composite material of AuNPs and graphene airgel is modified on the surface of the screen-printed electrode, and the aptamer is realized on the sensor by forming a gold-sulfur (AuS) bond with the sulfhydryl-modified DNA single-stranded aptamer. The modification of the PSA aptamer sensor is constructed by blocking the active site of excess gold with MCH. A certain concentration of PSA and UA is selected to incubate the sensor, and the EIS test method is used to detect PSA by recording its impedance change, and the detection limit of the sensor is obtained. The screen printing technology is used, which has the characteristics of large-scale batch manufacturing and low cost, and combined with the good physical and electrical properties of nanomaterials. The electrochemical sensor for the detection of prostate specific antigen is prepared to realize its convenient, efficient and low-cost detection, which provides a new way for the detection of prostate cancer patients outside of hospitals and laboratories. The method enables to solve the defect of the existing technology, provide a simple and portable, and realize instant monitoring and fast detection based on the screen printing aptamer sensor of the electrode. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) a PSA aptamer sensor based on a screen printing electrode, which is prepared based on the method for preparing PSA aptamer sensor based on screen-printed electrodes; and (2) a method for performing detection method of a PSA aptamer sensor based on electrode screen printing, which involves: (a) using the PSA aptamer sensor based on screen-printed electrodes, preparing different concentrations of antigen test solutions with pure phosphate-buffered saline (PBS), taking 10-15 microliter (μL) and dropping them into the working electrode area of the aptamer sensor, incubating at room temperature for 2-3 hours, rinsing the surface of the working electrode slowly with PBS for 3-5 times, blow-drying gently with nitrogen at a small flow rate, and storing at 0-4℃; and (b) using PBS to prepare a test electrolyte solution containing potassium ferricyanide, potassium ferrocyanide and potassium chloride, clamping the sensor to be tested to the electrochemical workstation, immersing the working area of the electrode completely in the electrolyte solution, performing detection and obtain impedance values, using curves of different colors to represent different PSA detection concentrations, and drawing electrochemical impedance spectra and linear fitting graphs.