Aptamer type biosensor for quickly detecting circulating tumor cells

The invention belongs to the technical field of biological detection, particularly relates to an aptamer type biosensor for quickly detecting circulating tumor cells, and also relates to a preparation method and application of the sensor. The aptamer type biosensor comprises a piezoelectric substrate, a reflecting grating array and an interdigital transducer, wherein a chromium film and a gold film are attached to the piezoelectric substrate in sequence; aptamers are wrapped on the surface of the gold film; the aptamers are oligonucleotide single chains of which the base sequences are shown as SEQ ID NO: 1. The aptamer type biosensor for quickly detecting the circulating tumor cells disclosed by the invention is high in sensitivity, high in specificity and high in affinity, and can be used for early diagnosis of tumor metastasis in an auxiliary manner.