Tumor-Targeted Folic Acid-Modified Porfimer Conjugated Poly (Ethylene Glycol) Nanoparticles for Radiosensitized Treatment of Cancer

Folic acid-modified porfimer conjugated poly (ethylene glycol) nanoparticles (FPP NPs), as the novel radiosensitizer, for tumor-targeted radiosensitized treatment (RST) were synthesized and characterized. Diamino poly (ethylene glycol) was covalently conjugated with folic acid and porfimer (also known as photofrin) in its terminal ends and self-assembled in aqueous solution to form FPP NPs. FPP NPs were characterized by FTIR spectrometer, zetasizer and transmission electron microscopy. FT-IR spectra of folic acid-modified porfimer conjugated poly (ethylene glycol) suggested that folic acid and porfimer were successfully covalently bound to poly (ethylene glycol) by amide bonds between carboxyl group and amino group. The average size and zeta potential of these nanoparticles were about 75nm and -13.5mV, respectively. And FPP NPs exhibited morphological features close to spherical shape by transmission electron microscopy observation. The loading efficiency and encapsulation efficiency of porfimer in FPP NPs were 8.52% and 45.67%, respectively. The experiments on reactive oxygen species (ROS) generation and cell viability showed that the nanoparticles could successfully suppress the growth of cancer cells by producing ROS with γ-ray irradiation. Furthermore, in vivo studies showed that FPP NPs exhibited the excellent tumor inhibition effect even at a half dose of free porfimer. These results suggested that FPP NPs would have potential for RST of the cancer.