▎ 摘　　要

NOVELTY - Preparing carcino-embryonic antigen immune electrochemical sensor with gold nano-particle-polydiallyldimethylammonium chloride-graphene (AuNPs-PDDA-GR) based composite material comprises (i) preparing AuNPs-PDDA-GR/ glassy carbon electrode GCE, (ii) preparing physically adsorbed carcino-embryonic antigen antibody (anti-CEA)/AuNPs-PDDA-GR/GCE, (iii) preparing bovine serum albumin (BSA)/anti-CEA/AuNPs-PDDA-GR/GCE, and (iv) preparing the immune electrochemical sensor. USE - The sensor is useful for detecting CEA (claimed). ADVANTAGE - The sensor has a linear range of 0.1 pg-10 ng/ml and has a detection limit of 0.05 pg/ml. DETAILED DESCRIPTION - Preparing carcino-embryonic antigen immune electrochemical sensor with gold nano-particle-polydiallyldimethylammonium chloride-graphene (AuNPs-PDDA-GR) based composite material comprises (i) polishing glassy carbon electrode (GCE) sequentially with 1 mu m, 0.3 mu m, 0.05 mu m aluminum oxide polishing powder to a diameter of 4 mm, carrying out ultrasonic cleaning with ethanol and ultrapure water for 3 minutes, blowing with nitrogen, dispersing 10 mu l AuNPs-PDDA-GR droplets, applying to the surface of the electrode, drying at room temperature to form film, washing with phosphate buffer saline (PBS) solution of pH 7.4 to remove unbound AuNPs-PDDA-GR to obtain AuNPs-PDDA-GR/GCE, (ii) applying 50 mu l 1-2.5 mu g/l carcino-embryonic antigen antibody (anti-CEA) standard solution drop-wise on to the electrode surface, incubating in a refrigerator at 4 degrees C for 12 hours, removing and washing with PBS solution of pH 7.4 to obtain physically adsorbed anti-CEA/AuNPs-PDDA-GR/GCE, (iii) adding 50 mu l 1-3 wt.% bovine serum albumin (BSA) drop-wise on the electrode surface, coating at 37 degrees C for 1 hours, blocking non-specific binding site with PBS fo pH 7.4 and rinsing the electrode to obtain BSA/anti-CEA/AuNPs-PDDA-GR/GCE, and (iv) adding 50 mu l 0.1 pg-10 ng/ml standard solution for carcino-embryonic antigen (CEA) of different concentration drop-wise with an antibody for specific recognition, incubating for 60 minutes at 37 degrees C and rinsing the electrode surface with PBS of pH 7.4 to obtain product. An INDEPENDENT CLAIM is also included for detecting CEA, comprising (i) carrying out the detection on electrochemical workstation, taking the immune sensor prepared by the above method in a three-electrode system as a working electrode, taking silver/silver chloride electrode as reference electrode, taking platinum electrode a counter electrode and testing in 10 ml 2x 10-4 mol/l potassium ferricyanide and 0.1 mol/l potassium chloride solution in PBS of pH 7.4, (ii) detecting different concentrations of CEA standard solution not binding specifically to electrode by differential pulse voltammetry series at the scanning potential range of -0.2 to 0.6 V the scanning speed of 100 mV/seconds, recording differential pulse in voltammogram and drawing a working curve according to the peak current values obtained by CEA and the linear logarithm of concentration, and (iii) detecting the sample solution in place of standard CEA solution.