The invention relates to a double-
signal aptamer sensor and a preparation method and application thereof, and belongs to the technical field of sensors. The dual-
signal aptamer sensor comprises a first compound, a second compound and a third compound, wherein the first compound comprises Au dimers and functionalized cDNA (
complementary deoxyribonucleic acid) modified on the Au dimers; the first compound is Fe3O4 (at) SiO2-CDs, and the second compound is Fe3O4 (at) SiO2-CDs and an
aptamer apt of
aflatoxin B1, wherein the aptamer apt of
aflatoxin B1 is modified on the Fe3O4 (at) SiO2-CDs; the Fe3O4 (at) SiO2-CDs comprise Fe3O4 (at) SiO2 and CDs which are modified on the Fe3O4 (at) SiO2; the first compound and the second compound are connected through complementary base
pairing to form an
assembly. Due to the introduction of the Raman
signal probe, the Raman signal of the
assembly is enhanced, meanwhile, the Au dimers have a
quenching effect on the
fluorescence of the magnetic substrate, and the
fluorescence signal of the
assembly is weakened. After the target is added, the aptamer is preferentially specifically combined with the target, the assembly is disassembled, the Au dimers fall off from the Fe3O4 (at) SiO2-CDs, and through
magnetic separation, a Raman signal of
precipitation is reduced along with the addition of the target, and a
fluorescence signal is recovered. The dual-mode detection is realized by measuring the change of Raman and fluorescence signals of the
precipitation part along with the target addition amount.