Target MicroRNA-Responsive DNA Hydrogel-Based Surface-Enhanced Raman Scattering Sensor Arrays for MicroRNA-Marked Cancer Screening

On the basis of a target microRNA (miRNA)-responsive DNA hydrogel, a novel surface-enhanced Raman scattering (SERS) sensor array with nine sensor units that can detect multiple cancer-related miRNAs in one sample was developed. The target miRNA-responsive DNA hydrogel was first formed in each sensor unit to realize the construction of the DNA hydrogel-based SERS sensor array. Initially, because of the blocking of the streptavidin (SA)-modified sensor units by the formed DNA hydrogel, the SERS tags (biotin/4-mercaptobenzonitrile-functionalized AuAg alloy nanoparticles (B/M-AuAgNPs)) could not pass through the hydrogel and bind to the SA-modified sensor surface; thus, obvious Raman signals could not be observed. After the introduction of the target miRNA, DNA hydrogels of the corresponding sensor unit were disintegrated accordingly, and SERS tags were able to pass through the hydrogel to be captured onto the SA-modified detection surface, thus resulting in strong Raman signals and the detection of target miRNA. The assay is validated under clean buffer conditions as well as in serum. This target miRNA-responsive DNA hydrogel-based SERS sensor array has attractive application prospects in cancer typing via blood miRNA measurements.