Upconversion nanoparticles–based targeted imaging of MCF-7 breast cancer cells.

Upconversion nanoparticles (UCNPs) doped with lanthanides are introduced as a significant tool in bioimaging applications. Here in, a comparative study has been performed to understand the cell internalization capacity of folic acid (FA) and arginine-glycine-aspartic acid-lysine (RGDK) ligands. To achieve this goal, polyacrylic acid (PAA) coated UCNPs (NaYF₄:Yb³⁺, Er³⁺) are conjugated with various surface ligands such as FA and RGDK through a straightforward ligand exchange procedure. Ligand conjugation to UCNPs was characterized with a transmission electron microscope (TEM), Fourier-transform infrared (FT-IR) spectroscopy, zeta potential measurements, nuclear magnetic resonance (NMR) spectroscopy, and NanoDrop measurements. The cellular uptake of the nanoparticles was investigated on the breast cancer MCF-7 cell line. The obtained results demonstrated that folic acid and RGDK functionalized UCNPs showed remarkably higher cellular uptake, which clearly indicates that the specific targeting of UCNPs provides a better quality of sub-cellular imaging at lower energy band region. [ABSTRACT FROM AUTHOR]