Mapping Selenium Nanoparticles Distribution Inside Cells through Confocal Raman Microspectroscopy

Selenium nanoparticles (SeNPs) exhibit significant potential in biomedical applications due to their antimicrobial, anticancer, and anti-inflammatory properties. In this study, we synthesized biocompatible SeNPs and employed confocal Raman microspectroscopy to map their distribution within human dermal fibroblast (HDF) cells. SeNPs possess a distinctive Raman band placed outside the cellular fingerprint region, which facilitates its detection and precise Raman imaging. Viability assays revealed that SeNPs exhibit cytotoxic effects only at the highest concentrations and for long exposure times while resulting in no harmful effects during all of the other treatments. For the first time, we achieved three-dimensional (3D) Raman mapping of SeNPs within cells, providing insights into their cellular penetration. Additionally, two-dimensional (2D) Raman mapping performed at different times and at sublethal concentrations demonstrated dynamic uptake and confirmed internalization. These findings highlight the effectiveness of SeNPs for biomedical imaging and therapeutic applications, offering an additional approach to studying nanoparticle-cell interactions.