▎ 摘　　要

NOVELTY - Electrochemical immune sensor comprises a graphene strip (GNR), 3,4,9,10-perylene tetracarboxylic acid (PTCA) fixed on the surface of graphene ribbon (GNR) by pi - pi stacking, bovine serum albumin (BSA) fixed on the surface of the graphene strip (GNR) by means of amide bond, primary antibody (PAb) immobilized on the surface of 3,4,9,10-perylenetetracarboxylic acid (PTCA) by means of amide bond, gold nanoparticles (Au-NPs), ferrocene derivatives (Fc-SH) immobilized on the surface of gold nanoparticles (Au-NPs) through Au-S bonds and secondary antibody (SAb) adsorbed on the surface of gold nano particles (Au-NPs) by means of electrostatic. USE - Used as electrochemical immune sensor. ADVANTAGE - The sensor improves the sensing performance, has good analytical performance and a wide linear range of (10-2x 104 CFU/ml) and low detection limit of 6 CFU/ml with ideal specificity. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the immunesensor, comprising (i) dispersing 50 mg carbonnano-tube (CNT) in concentrated sulfuric acid/phosphoric acid (volume ratio of 9: 1) in the glass bottle for 1 hour, adding 250 mg potassium permanganate, heating the formed mixture to 65 degrees C, heat preserving for 2 hours, pouring into the ice water containing hydrogen peroxide to make the reaction quenching, filtering, washing and drying to obtain the initial graphene oxide nano-belt (GONR), adding aqueous ammonia and hydrazine solution in the GONR dispersion liquid, heating for 10 hours at 60 degrees C, filtering and washing to obtain GNR, ultrasonically processing 50 mg GNR in 100 ml ethanol containing 20.0 mg PTCA for 1 h, and continuously stirring the solution for 2 hours at room temperature, filtering the obtained mixture by nylon film (0.22 mm), washing for many times and drying to form PTCA/GNR; (ii) dropping the 0.2 mol L-1sodium citrate (400 l) to 0.2 mg/ml chloroauric acid solution (12 ml), and heating for 2 hours at 60 degrees C, centrifuging to obtain gold nano-particle and drying, adding 20 mu l SAb to 1 ml gold nanoparticle solution and incubating for 2 hours, adding 1 mM Fc-SH solution (20 mu l) to SAb gold nanoparticle solution to obtain SAb-AuNPs-Fc, adding 20 mu l SAb to 1 ml gold nanoparticle solution and incubate for 2 hours and adding 1 mM Fc-SH solution (20 mu l) to SAb gold nanoparticle solution to obtain SAb-AuNPs-Fc; (iii) dropping 12 l PTCA/GNR suspension (0.5 mg/ml) on the polished glass carbon electrode (GCE) surface, and using carbodiimide/N-hydroxysuccinimide (EDC/NHS) mixture to activate the carboxy group, dropping 12 mu l primary antibody (PAb) on the surface of activated PTCA/GNR/GCE, denoted as PAb/PTCA/GNR/GCE, rinsing PAb/PTCA/GNR/GCE with phosphate buffer (PBS) to remove unbound PAb, incubating with bovine serum albumin (BSA) to prepare BSA/PAb/PTCA/GNR/GCE; (iv) dropping the 0.2 mol/l sodium citrate (400 l) to 0.2 mg/ml chloroauric acid solution(12 ml), and heating for 2 hours at 60 degrees C, centrifuging to obtain gold nano-particle AuNPs and drying, adding 20 l SAb (0.05 mg/ml) incubation for 2 hours in the 1 ml gold nano-particle solution, adding 1 mM Fc-SH solution(20 l) in the SAb gold nano-particle solution toobtain SAb-Au NPs-Fc