The invention discloses a capillary SERS (Surface Enhanced
Raman Scattering) sensor based on
CRISPR / Cas13a (Clustered Regularly Interspaced Short Palindromic Repeats /
CRISPR associated 13a), a preparation method of the capillary SERS sensor and application of the capillary SERS sensor to detection of a
hepatocellular carcinoma marker miR-221, the method comprises the following steps: 1) adopting a seed growth method, firstly synthesizing a decahedral gold nano seed, and on the basis, continuing to react and grow to obtain
dumbbell-shaped gold and
silver nano rods (DS Au-AgNRs); (2) dispersing the DS Au-AgNRs prepared in the step (1) into a PVP
ethanol solution, and assembling the DS Au-AgNRs onto an aminated capillary tube by utilizing the interaction of PVP groups on the surfaces of nano-particles and amino groups on the inner wall of the capillary tube, so as to obtain a capillary tube SERS (Surface Enhanced
Raman Scattering) substrate; and 3) modifying the surface of the capillary SERS substrate prepared in the step 2) with a single-stranded
DNA modified with sulfydryl and Raman
signal molecules (Cy5) through a gold-
sulfur bond to construct the SERS sensor.The capillary SERS sensor provided by the invention has the advantages of high sensitivity, high specificity, convenience in sampling, low cost and the like, and is expected to provide a novel method with a prospect for early diagnosis of HCC.