The invention discloses a
label-free ratio
fluorescence type antigen detection method. The method comprises the following steps: designing a single-stranded
DNA which comprises a recognition
DNA sequence for
CRISPR and an
aptamer of a
target antigen, and constructing a component A by spacing the recognition
DNA sequence and the
aptamer through a plurality of continuous T basic groups; by taking a
target antigen as a target, modifying an
antibody of the
target antigen on a 96-well plate to construct a component B; connecting the surface-carboxylated
silicon dioxide microspheres with
a DNA chain of which the
tail end is modified with amino groups, and complementarily
pairing auxiliary DNA with DNA with amino groups to form double chains, so as to construct a component C; adding the component A, the component B, the component C,
copper ions,
ascorbic acid,
DAPI dye and
exonuclease III into an object to be detected; and detecting
red fluorescence and blue
fluorescence of an object to be detected, and detecting the target
antigen by a ratio
fluorescence method. According to the ratio fluorescence method, the intensities of two kinds of fluorescence are compared to serve as
signal parameters, the accuracy is higher, the sensitivity is higher, and the selectivity is better; and moreover, the sensitivity is improved, the defect that a traditional method needs to
label an
antibody is overcome, and the detection cost is saved.