The invention relates to an
aptamer specifically combined with beta-lactoglobulin and application of the
aptamer, and belongs to the technical field of biological detection. According to the
aptamer and the preparation method thereof, a
binding domain base, participating in recognition, of the aptamer is predicted through molecular docking firstly, then the
binding domain base is subjected to directional
mutation, the aptamer with the recognition performance improved is obtained, the affinity of the aptamer to beta-lactoglobulin is 10.6 nM, and the aptamer has no recognition capacity on alpha-
lactalbumin,
casein,
bovine serum albumin, immune
globulin G,
lactose and the like and can be used for preparing the aptamer with the recognition performance improved. Therefore, the aptamer disclosed by the invention has good sensitivity and specificity on the beta-lactoglobulin. On the basis, a
fluorescence polarization method is directly constructed by utilizing the characteristic that the beta-lactoglobulin is a biomacromolecule, when the beta-lactoglobulin exists, an aptamer marked by a
fluorophore FAM recognizes the beta-lactoglobulin to form an aptamer beta-lactoglobulin compound, and the
fluorescence polarization value is relatively large, so that the beta-lactoglobulin compound can be used for identifying the beta-lactoglobulin. Therefore, the
specific detection of the low-concentration beta-lactoglobulin is realized.