Fig. 5: Surface-enhanced Raman Scattering for targeting miR-17.
From: Biomarkers and point of care screening approaches for the management of preeclampsia
The SERS-based assay for the quantification of miR-17 uses silver nanoparticle probes modified with split DNA strands complementary to miR-17 sequence. A typical SERS detection can be achieved by functionalization of plasmonic nanoparticles with Raman dyes (Malachite green in this study) and DNA sequences or antibodies that conjugate with the targets. The mechanism is based on the ‘hotspots’ formation between the plasmonic nanoparticles when aggregation occurs after the bind of targets. The Raman signal at the ‘hotspot’ region can be amplified because of the crosstalk between the electromagnetic field and charge transfer between two nanoparticles142. DNA sequences functionalized on AgNPs can hybridize with the target hsa-miR-17-5p from 3’ to 5’ end to form a triplex structure without overhung base pair. In the presence of hsa-miR-17-5p, the SERS-active, DNA-functionalized AgNPs will aggregate. Therefore, the SERS output from the malachite green reporter significantly increases compared to the absence of hsa-miR-17-5p due to plasmonic coupling between the nanoparticles caused by their hybridization to the miRNA target. Using this method miR-17 can be detected across a range of 1 pM to 1 nM (n = 5). The error bars represent the standard deviation calculated from five spectra, with each spectrum being the average of 10 consecutive 1 second scans124. Created with BioRender.com
