Graphene Oxide Covalently Grafted Fe₂B@SiO₂ Nanoparticles for Epirubicin Loading and Releasing.

In this work, stable superparamagnetic core-shell Fe₂B@SiO₂ nanoparticles were prepared by "one pot" chemical reduction of ferric ion salts with NaBH₄ and silica shell coating in the presence of citric acid stabilizer. The X-ray (XRD) and selection of electron diffraction (SAED) revealed that Fe₂B@SiO₂ nanoparticles were chiefly composed of silica shell and Fe₂B with a small amount of α-Fe. Then, graphene oxide (GO) was assembled onto core-shell Fe₂B@SiO₂ nanoparticles for Epirubicin (EPI) loading and releasing, and the adsorption isotherm of EPI on Fe₂B@SiO₂@GO was analyzed. The results showed, the adsorption process includes two steps, due to the π-π stacking effect of EPI on the Fe₂B@SiO₂@GO. The EPI loading efficiency of the magnetic nanoparticles was as high as 90%, while the EPI-loaded core-shell Fe₂B@SiO₂ nanoparticles showed an obvious pH controlled drug release behavior, and showed lower cumulative release rate when pH is 7.4 than that when pH is 5.7. The prepared nanoparticles demonstrated potential application in killing tumor cells while minimizing the toxicity to normal tissues.