Folic Acid-Conjugated, SERS-Labeled Silver Nanotriangles for Multimodal Detection and Targeted Photothermal Treatment on Human Ovarian Cancer Cells

The effectiveness of a therapeutic agent for cancer stands in its ability to reduce and eliminate tumors without harming the healthy tissue nearby. Nanoparticles peripherally conjugated with targeting moieties offer major improvements in therapeutics through site specificity. In this study we demonstrate this approach by targeting the folate receptor of NIH:OVCAR-3 human ovary cancer cell line. Herein we used silver nanotriangles which were biocompatibilized with chitosan (bio)polymer, labeled with para-aminothiophenol (pATP) Raman reporter molecule, and conjugated with folic acid. The nanoparticles conjugation and efficient labeling was investigated by localized surface plasmon resonance (LSPR), zeta potential, and surface-enhanced Raman scattering (SERS) measurements. Conjugated particles were proven to be highly stable in aqueous and cellular medium. The targeted uptake of conjugated nanoparticles by human ovary cancer cells was confirmed by dark field microscopy and scattering spectra of the particles inside cells. Comparative studies revealed specific internalization of the conjugated nanoparticles in comparison with similar bare nanoparticles. Moreover, the SERS identity of the particles was proven to be highly conserved inside cells. Targeted cancer cell treatment conducted by irradiating the nanoparticle-treated cells with a continuous wave-nearinfrared (cw-NIR) laser in resonance with their plasmonic band proved an efficient therapeutic response. By integrating the advantages of multimodal optical imaging and SERS detection with hyperthermia capabilities through site specificity, these nanoparticles can represent a real candidate for personalized medicine.