Retractable DNA Nanoprobes for Ultrasensitive SERS Detection and Imaging of the VEGF

Vascular endothelial growth factor (VEGF) is a key signaling protein in the regulation of angiogenesis, and the dysregulation of its expression is associated with the development of various diseases such as tumorigenesis. The traditional fluorescence detection methods for the VEGF are prone to photobleaching and are easily interfered by autofluorescence of the sample, resulting in insufficient detection stability and accuracy. In order to develop a stable and accurate method for VEGF detection, an ultrasensitive surface-enhanced Raman scattering biosensor was constructed in this study by designing a scalable Au/DNA/SiO₂ nanoprobe (named ADSNP). In the ADSNP, we labeled the Prussian blue (PB) Raman molecules, whose characteristic peaks are in the silent region, effectively avoiding signal interference from the biomolecules. Meanwhile, the distance modulation between Raman molecules and Au nanoparticles was achieved by using stretchable DNA nanostrands, which in turn responded to different concentrations of the VEGF. Assisted by the aptamer nucleic acid amplification strategy, trace VEGF would cause a high Raman signal response. In addition, the ADSNP can image the VEGF in living cancer cells. Therefore, this study provides a feasible method for the identification and detection of cancer markers in cells, as well as a potential value for observing cellular biochemical responses.