Surface-enhanced Raman scattering for HSP 70A mRNA detection in live cells using silica nanoparticles and DNA-modified gold nanoparticles.

Real-time monitoring of mRNA in living cells is crucial for understanding dynamic biological processes. Traditional methods such as northern blotting, PCR, and sequencing require cell lysis and do not allow for continuous observation. Fluorescence-based techniques have advanced this field, but they are limited by photobleaching, which hinders long-term monitoring. In this study, we designed a dual-probe system combining fluorescence and surface-enhanced Raman scattering (SERS) signals to monitor mRNA in living cells. Our system uses silica nanoparticles (SiNPs) with DNA sequences which are hybridized with fluorescent DNA sequences and DNA-modified gold nanoparticles (AuNPs) to detect heat shock protein 70A mRNA, which can be induced by photothermal damage from laser exposure. Following nanoparticle uptake and induction of heat shock, we observed a time-dependent decrease in fluorescence intensity and increase in SERS intensity, indicating successful mRNA monitoring in living cells. These findings suggest that our dual-probe system with SiNPs and AuNPs is a promising nanotechnological platform for sensitive, long-term monitoring of gene expression in living cells, offering significant potential for future biological and medical research.