▎ 摘　　要

NOVELTY - Aptamer nano colorimetric biosensor comprises an aptamer and a nano material, where aptamer is adsorbed on the nano material, and aptamer including nucleotide sequence selected from sequences including 18-88 nucleobases of (SEQ ID NOs: 1-5), given in the specification. The nano material has peroxidase-like activity, and peroxidase-like activity is enhanced when the aptamer is adsorbed on the nano material. USE - Aptamer nano colorimetric biosensor used in manufacture of product for diagnosis of sepsis and detecting Escherichia coli. ADVANTAGE - The aptamer nano colorimetric biosensor has good specificity and high sensitivity, and applied to detection of Escherichia coli and preparation of products for diagnosing sepsis. The Escherichia coli is detected in simple and convenient manner, which quickly and accurately realize qualitative and quantitative detection of the Escherichia coli, reduces the detection time of the Escherichia coli, and reduces the detection cost. DETAILED DESCRIPTION - Aptamer nano colorimetric biosensor comprises an aptamer and a nano material, where aptamer is adsorbed on the nano material, and aptamer including nucleotide sequence selected from sequences including 18-88 nucleobases of (SEQ ID NOs: 1-5), that is atccgtcacacctgctct. The nano material has peroxidase-like activity, and peroxidase-like activity is enhanced when the aptamer is adsorbed on the nano material. INDEPENDENT CLAIMS are included for: (1) Product for diagnosing sepsis, which comprises the aptamer nanopigmented biosensor. (2) Method for detecting Escherichia coli, which involves mixing an aptamer and the protein gold nanocluster, performing primary incubation, then adding escherichia coli with a known concentration, performing secondary incubation, then adding hydrogen peroxide and 3,3',5,5'-tetramethyl benzidine, performing tertiary incubation, and then detecting absorbance at a wavelength of 652nm to obtain a relation between the concentration of the escherichia coli and the absorbance; mixing the aptamer and the protein gold nanocluster, performing primary incubation, adding a sample to be detected, performing secondary incubation, adding hydrogen peroxide and 3,3',5,5'-tetramethylbenzidine, performing tertiary incubation, detecting absorbance at the wavelength of 652nm, and calculating the concentration of escherichia coli in the sample to be detected according to the relationship between the concentration of enterobacter and the absorbance obtained.